JP2009080247A - Toner for developing electrostatic charge image, method for forming image using it, and image forming apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a toner superior in image stability without any stain or the like in long period use even when using a high speed printer by suppressing stain of an image not-written part caused by an existence ratio of powder of a specific particle diameter or less, remaining images (ghost), and fading (solid followability) or the like, and having image quality and cleanability. <P>SOLUTION: In the toner used for a method for developing electrostatic charge images and cleaning transfer remaining images with a cleaning blade, an external additive is added to toner mother particles. A value dividing "a BET specific surface area of the toner" by "a spherical supposition specific surface area calculated from a volume middle size (Dv50) of the toner" is 3.0 or less. The volume middle size (Dv50) of the toner is 4.0-7.0 μm. An inequality: Dns≤0.233EXP(17.3/Dv50) wherein Dv50 denotes a volume middle size (μm) of a toner, and Dns denotes the number-of-pieces% of the toner of a particle size of 2.00-3.56 μm is satisfied. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electrostatic charge image developing toner used in electrophotography, electrostatic photography, and the like, and an image forming method and an image forming apparatus using the same.

  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 particular, in office documents, in addition to the development of mapping technology and latent image forming technology for input, the types of character hieroglyphics are more abundant and finer at the time of output. Due to the spread and development, the reproducibility of a latent image with extremely high image quality that has few defects and unclearness in printed images is required. In particular, as a developer used when the electrostatic latent image on the latent image carrier constituting the image forming apparatus is a line image of 100 μm or less (approximately 300 dpi or more), a conventional toner having a large particle diameter is used as a fine line reproducibility. In general, the line image is not clear enough.

  In particular, in an image forming apparatus such as an electrophotographic printer using a digital image signal, a latent image is formed by gathering a certain number of dot units, and the solid portion, the halftone portion, and the light portion have different dot densities. It is expressed by However, if the toner is not arranged faithfully in the dot unit and the mismatch between the position of the dot unit and the position of the actually placed toner occurs, this corresponds to the ratio of the dot density of the black portion and the white portion of the digital latent image. There is a problem that the gradation of the toner image cannot be obtained. Furthermore, when the resolution is improved by reducing the dot size in order to improve the image quality, a phenomenon faithful to the latent image formed from the minute dots becomes more difficult, and the resolution is high and the gradation is poor. There is no denying the tendency for images to lack sharpness.

  Furthermore, with the advent of blue lasers, it is expected that the electrostatic latent image dot size will be further reduced in the future, and there is a demand for a toner for developing an electrostatic charge image corresponding to that, and an image forming method and an image forming apparatus using the same. Has been.

  In view of this, there has been proposed a device intended to improve the image quality by improving the reproducibility of minute dots by regulating the particle size distribution of the developer. Patent Document 1 proposes a toner having an average particle size of 6 to 8 μm, and attempts to form a latent image of fine dots with high reproducibility by reducing the particle size. Patent Document 2 discloses a toner base particle containing a toner having a weight average particle diameter of 4 to 8 μm and further containing 17 to 60% by weight of toner base particles having a particle diameter of 5 μm or less. Patent Document 3 discloses a magnetic toner containing 17 to 60% by number of magnetic toner base particles having a particle size of 5 μm or less. Patent Document 4 discloses toner base particles in which the content of toner base particles having a particle size of 2.0 to 4.0 μm is 15 to 40% by number in the toner particle size distribution.

  Further, Patent Document 5 describes a toner in which particles of 5 μm or less are about 15 to 65% by number. Further, Patent Documents 6 and 7 disclose similar toners. Further, Patent Document 8 contains 17 to 60% by number of toner base particles having a particle size of 5 μm or less, 1 to 30% by number of toner base particles having a particle size of 8 to 12.7 μm, and 16 μm. A toner having a specific particle size distribution in a toner having a volume average particle diameter of 4 to 10 μm and a toner having a specific particle size distribution is described. Further, in Patent Document 9, in the toner particles having a 50% volume particle diameter of 2 to 8 μm, the number of toner particles having a particle diameter of “0.7 × 50% number particle diameter” or less is 10 number% or less. Is described.

  However, all of these toners contain a large amount of particles having a particle size of 3.56 μm or less exceeding the upper limit of the right side of the formula (1) of the present invention. In this relative relationship, it is a toner in which a relatively large amount of fine powder remains with respect to a toner having a predetermined particle diameter. In such a toner, the ratio of fine powder is still large, and the following problems remain.

JP-A-2-284158 JP-A-5-119530 JP-A-1-221755 JP-A-6-289648 JP 2001-134005 A Japanese Patent Laid-Open No. 11-147331 Japanese Patent Laid-Open No. 11-362389 JP-A-2-000877 JP 2004-045948 A

  Further, in recent years, life extension and high-speed printing have been demanded along with market demand for image quality. However, these required characteristics have not been sufficiently satisfied with the conventional toner. If there is a lot of fine powder like conventional toner, the fine powder will contaminate the member with continuous printing, the charge imparting ability to the toner will be reduced and the image will be distorted, and if it is introduced into a high speed printer, toner scattering will be noticeable There were also challenges.

  In order to provide high image printing, the toner particle size distribution needs to be sharp. This is because when the coarse particles are contained, the toner charge amount distribution becomes broad and a phenomenon called “selective development” occurs. “Selective development” is a phenomenon in which, when the toner charge amount distribution is broad, only the toner having the charge amount necessary for development at the time of copying is developed and consumed. Therefore, a good image can be obtained at the initial stage of copying, but the density gradually decreases as the copying continues, and the toner particle size increases, resulting in a rough image. This phenomenon is said to be inferior in selective developability. Furthermore, the coarse powder having a low charge amount tends to significantly reduce the guaranteed life number. Patent Document 10 discloses a toner having a large number of coarse powders having a number variation coefficient of 24.2%. Such a toner is not suitable for stably providing a high-resolution image. Further, Patent Document 11 does not indicate that the particle size distribution is sharp.

JP 2003-255567 A WO2004-088431

  Furthermore, it is necessary to pay attention to toner transfer characteristics in order to provide high-quality printing. The toner having high transfer characteristics refers to toner having high transfer efficiency from the electrophotographic photosensitive member to the intermediate transfer drum or paper, or high transfer efficiency from the intermediate transfer drum to paper. Patent Documents 12 to 14 disclose pulverized toner that does not have a high average circularity from the viewpoint of the manufacturing process, which is insufficient to provide high-quality printing.

Japanese Patent Laid-Open No. 7-098521 JP 2006-091175 A JP 2006-119616 A

  Here, in the electrophotographic apparatus, the toner developed into the electrostatic latent image on the electrostatic charge image holding member is transferred to a printed matter such as paper. In some cases, the image is not transferred directly from the electrostatic charge image holding member to the paper but is transferred via an intermediate transfer member. In this transfer step, the toner is not completely transferred from the electrostatic charge image holding member, and a small amount becomes a transfer residual toner and remains on the electrostatic charge image holding member. Therefore, after the transfer process, a cleaning process for removing the untransferred toner from the electrostatic charge image holding member is required.

  Conventionally, many cleaning blade methods have been used for such a cleaning process. That is, a cleaning blade formed of a material such as urethane rubber having a relatively low elastic modulus is brought into contact with the electrostatic charge image holding member, and the transfer residual toner is scraped off by relative movement of the cleaning blade and the electrostatic charge image holding member. . The leading edge of the cleaning blade is in contact with the electrostatic charge image holding member and blocks the transfer residual toner. The leading edge ridge line is elastically deformed with the movement of the electrostatic charge image holding member in a state of being attached to the electrostatic charge image holding member due to the static frictional resistance force with the electrostatic charge image holding member, and the elastic repulsive force reduces the static frictional resistance force. When it exceeds, it is released and returns to its original shape. Further, the micro-vibration by the above-described process of repeating the elastic deformation once again with the electrostatic charge image holding member in the returned state is repeated. This phenomenon is called “stick and slip”.

  Even if stick-and-slip occurs, the clogged toner remaining after transfer does not leak from the gap between the cleaning blade and the electrostatic charge image holding member, and is used for toner cleaning. It is sometimes difficult to completely dampen easy particles.

  Complete cleaning of small particles requires strict control of the position accuracy of the parts. Further, if many small particles are contained as compared with the average particle diameter, there is a high possibility that the transfer residual toner slips through the cleaning blade. In recent years, there has been a shift from pulverized toner to wet toner, but compared to pulverized toner, wet toner has a smooth surface and is easy to slip through. In recent years, a lot of toners whose surface is smoothed by heat or mechanical treatment have appeared as pulverized toners, and these toners are easily slipped through. Accordingly, an image forming method in which toner particles are difficult to slip through is increasingly desired.

  Regarding the stick-and-slip phenomenon, the vibration width and vibration cycle are static friction resistance force and dynamic friction resistance force between the cleaning blade and the electrostatic charge image holding member (related to the speed at which the cleaning blade returns to its original shape). Depends on. Depending on the vibration width and vibration cycle, toner particles having a specific particle size, shape, and ease of slipping may be particularly easily slipped through. In this way, it is extremely difficult to theoretically handle the phenomenon that a particular particle is particularly easy to slip through, and how the toner, electrostatic charge image holding member, and cleaning blade can be made difficult to slip through. There was not enough knowledge yet.

  The slipped toner particles and free external additives may cause a charging failure of the photosensitive drum due to contamination of the charging roller or the like, and may directly cause an image failure on printing.

  Among the market demands for reducing the particle size of toner for higher resolution, it is necessary to provide technology with stable cleaning performance. As mentioned above, the emergence of wet toner and pulverized toner with a smooth surface have emerged. The need is getting stronger, but there is not enough technology.

  On the other hand, toner generally has an external additive attached to the surface of the toner base particles, but various studies and proposals have been made regarding the type and amount of the external additive. Adequate examination has not been made. Even if the type and amount of the external additive are the same, the image quality varies greatly if the adhesion state and the degree of burying in the toner are different. There are also problems. It is becoming more important to prepare a new toner by consciously and precisely controlling the adhesion state of the external additive as the particle size of the toner is reduced.

  The present invention has been made in view of the above-mentioned background art, and the problem is that the white background portion of the image due to the presence of fine powder having a specific particle size or less, afterimage (ghost), blur (solid followability), etc. Toner that can improve image quality while suppressing, especially good cleanability, no toner scattering even when using a high-speed printing machine, improved problems such as dirt during long-term use, and excellent image stability Is to provide. In addition, the cleaning performance is particularly stable, suppressing the occurrence of dirt and image defects in the device due to poor cleaning, the above problems are less likely to occur even after long-term use, the image quality is good, and the image stability is improved. The object is to provide an excellent image forming method.

  As a result of intensive studies to solve the above-mentioned problems, the present inventor has found that toner particles having a specific particle size or specific It has been found that only a toner having a particle size distribution has a phenomenon that it is more difficult to slip through, and it has been found that the above problem can be solved when a specific relational expression regarding the toner particle size is satisfied.

  Further, by paying attention to the dynamic friction coefficient of the electrostatic charge image holding member, it has been found that a more stable cleaning performance is exhibited by combining the toner forms.

  Furthermore, as a result of intensive studies to solve the above-mentioned problems, the present inventor limits the burying constant described later by precisely controlling the adhesion state of the external additive in the small particle size toner. The present inventors have found that the above problems can be solved and have completed the present invention.

That is, the present invention relates to a toner used in an electrostatic charge image developing method for cleaning a transfer residual toner with a cleaning blade, wherein the toner is obtained by adding an external additive to toner base particles. The value obtained by dividing the “BET specific surface area” by the “spherical assumed specific surface area calculated from the toner volume median diameter (Dv50)” is 3.0 or less, and the toner volume median diameter (Dv50) is 4.0 μm. The relationship between the volume median diameter (Dv50) and the number% (Dns) of the toner having a particle diameter of 2.00 μm to 3.56 μm satisfies the following formula (1). The toner to be used is provided.
(1) Dns ≦ 0.233EXP (17.3 / Dv50)
[In the formula, Dv50 represents the volume median diameter (μm) of the toner, and Dns represents the number% of the toner having a particle diameter of 2.00 μm to 3.56 μm. ]

  The present invention also includes a development step for attaching toner to the electrostatic image on the surface of the electrostatic charge image holding member, a transfer step for transferring the toner on the electrostatic charge image holding member to a transfer material, and a transfer step. And a cleaning step for cleaning residual toner remaining on the electrostatic charge image holding member, wherein the toner is the toner, and the cleaning blade is attached to the electrostatic charge image holding member in the cleaning step. The image forming method is characterized in that the toner remaining after transfer is brought into contact with the toner to be cleaned.

  The present invention also provides the above-described image forming method which includes a step of uniformly charging an electrostatic charge image holding member and using a contact-type charging member in the step of uniformly charging.

  The present invention also provides an image forming apparatus using the above toner.

  The present invention also provides an image forming apparatus using the above-described image forming method.

  According to the present invention, it is possible to suppress the occurrence of dirt and image defects on the parts in the apparatus due to defective cleaning, toner scattering, etc., and to prevent the above problems from occurring even when used for a long period of time, and image formation with excellent image stability. A method can be provided. In addition, it is possible to supply toner with excellent image stability by suppressing the occurrence of stains, afterimages (ghosts), blurring (solid followability), etc. on the white background of the image. In addition, even when an image is formed by the high-speed printing method, the toner particle size distribution is narrow, and even if the toner particle size is reduced, the amount of fine powder is small and the fixability is improved.

  Hereinafter, the present invention will be described. However, the present invention is not limited to the following embodiments, and can be arbitrarily modified and implemented.

  The toner for developing an electrostatic charge image of the present invention (hereinafter sometimes abbreviated as “toner”) is not particularly limited in its production method, and the configuration described below may be arbitrarily adopted. .

<Configuration of toner>
The toner of the present invention is configured using at least a binder resin, a colorant, a wax, an external additive, and the like as appropriate.

  The binder resin constituting the toner of the present invention may be appropriately selected from those known to be usable for toner. For example, styrene resin, vinyl chloride resin, rosin modified maleic acid resin, phenol resin, epoxy resin, saturated or unsaturated polyester resin, polyethylene resin, polypropylene resin, ionomer resin, polyurethane resin, silicone resin, ketone resin, Ethylene-acrylate copolymer, xylene resin, polyvinyl butyral resin, styrene-alkyl acrylate copolymer, styrene-alkyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-butadiene copolymer, styrene-anhydrous malein An acid copolymer etc. can be mentioned. These resins can be used alone or in combination.

  The colorant constituting the toner of the present invention may be appropriately selected from those known to be usable for toner. For example, yellow pigments, magenta pigments, and cyan pigments shown below can be used. As black pigments, carbon black or a mixture of the following yellow pigments / magenta pigments / cyan pigments toned to black is used. .

  Among these, carbon black as a black pigment exists as an aggregate of very fine primary particles, and when dispersed as a pigment dispersion, coarsening of particles due to reaggregation tends to occur. The degree of reagglomeration of carbon black particles correlates with the amount of impurities contained in carbon black (the degree of residual undecomposed organic matter). If there are many impurities, coarsening due to reaggregation after dispersion tends to be severe. showed that. As a quantitative evaluation of the amount of impurities, the ultraviolet absorbance of the toluene extract of carbon black measured by the following method is preferably 0.05 or less, and more preferably 0.03 or less. Generally, carbon black produced by the channel method tends to have a large amount of impurities, and therefore, carbon black produced by the furnace method is preferred as the carbon black in the present invention.

  The ultraviolet absorbance (λc) of carbon black is determined by the following method. First, 3 g of carbon black was sufficiently dispersed and mixed in 30 ml of toluene. Filter using 5C filter paper. Thereafter, the filtrate was put in a quartz cell having a 1 cm square light absorption part, and the value (λs) measured for absorbance at a wavelength of 336 nm using a commercially available ultraviolet spectrophotometer, and the value obtained by measuring the absorbance of toluene alone as a reference using the same method. From (λo), the ultraviolet absorbance is obtained by λc = λs−λo. Examples of commercially available spectrophotometers include an ultraviolet-visible spectrophotometer (UV-3100PC) manufactured by Shimadzu Corporation.

  As yellow pigments, compounds typified by condensed azo compounds, isoindolinone compounds and the like are used. Specifically, C.I. I. CI Pigment Yellow 12, 13, 14, 15, 17, 62, 74, 83, 93, 94, 95, 109, 110, 111, 128, 129, 147, 150, 155, 168, 180, 194, etc. are preferably used. It is done.

  As the magenta pigment, condensed azo compounds, diketopyrrolopyrrole compounds, anthraquinones, quinacridone compounds, basic dye lake compounds, naphthol compounds, benzimidazolone compounds, thioindigo compounds, and perylene compounds are used. Specifically, C.I. I. Pigment Red 2, 3, 5, 6, 7, 23, 48: 2, 48: 3, 48: 4, 57: 1, 81: 1, 122, 144, 146, 166, 169, 17.3, 184, 185, 202, 206, 207, 209, 220, 221, 238, 254, C.I. I. Pigment Violet 19 or the like is preferably used. Among them, C.I. I. Pigment red 122, 202, 207, 209, C.I. I. A quinacridone pigment represented by pigment violet 19 is particularly preferred. Among the quinacridone pigments, C.I. I. A compound represented by CI Pigment Red 122 is particularly preferable.

  As the cyan pigment, copper phthalocyanine compounds and derivatives thereof, anthraquinone compounds, basic dye lake compounds, and the like can be used. Specifically, C.I. I. Pigment blue 1, 15, 15: 1, 15: 2, 15: 3, 15: 4, 60, 62, 66 and the like; I. Pigment Green 7, 36, etc. can be used particularly preferably.

<Method for producing toner mother particles>
The method for producing the toner used in the image forming apparatus of the present invention is not particularly limited. That is, the toner can be produced by a pulverization method or a method of forming particles in an aqueous medium. When a toner is manufactured by a pulverization method, fine particles are generally easily generated, so that a classification step is necessary. In particular, an excessive classification operation may be required in order to satisfy the toner particle size requirement in the present invention, and the yield is remarkably reduced. Such an operation is not preferable from an industrial point of view. The pulverized toner is not excluded as the toner used in the image forming apparatus. On the other hand, it is preferable that the toner of the present invention forms particles in an aqueous medium from the viewpoint that it is difficult to generate fine powder and a classification step is not essential.

  As a production method for obtaining toner particles in an aqueous medium (hereinafter sometimes abbreviated as “wet method”), a method of radical polymerization in an aqueous medium such as a suspension polymerization method or an emulsion polymerization aggregation method (hereinafter referred to as “wet method”). An abbreviated “polymerization method” and the obtained toner may be abbreviated as “polymerized toner”), a chemical pulverization method represented by a melt suspension method, or the like can be suitably used. There is no particular limitation on the method for making the toner have a particle size in the specific range of the present invention. For example, in the production process of the polymerized toner, in the case of the suspension polymerization method, a method in which a high shearing force is applied in the process in which polymerizable monomer droplets are generated, or a dispersion stabilizer or the like is increased.

  As a method for obtaining a toner having a particle size in the specific range of the present invention, any of a polymerization method such as a pulverization method, a suspension polymerization method, an emulsion polymerization aggregation method, a chemical pulverization method represented by a melt suspension method, etc. Production methods can also be used, but in the “pulverization method”, “suspension polymerization method”, and “chemical pulverization method represented by the melt suspension method”, all of them are larger than the particle diameter of the toner. In order to adjust to a small size, if it is attempted to reduce the average particle size, the particle size ratio on the small particle side tends to increase, and an excessive burden is imposed in the classification step and the like. In contrast, the emulsion polymerization agglomeration method has a relatively sharp particle size distribution and is adjusted from a size smaller than the particle size of the toner to a larger size. A toner having a distribution is obtained. Therefore, for the above reasons, it is particularly preferable to produce the toner used in the image forming apparatus of the present invention by the emulsion polymerization aggregation method.

  In the pulverized toner, a classification step is usually essential. However, according to the wet method, particularly the emulsion polymerization aggregation method, the specific particle size distribution of the present invention can be obtained directly without classification. Therefore, in the present invention, it is preferable to produce toner base particles without having a step of removing a part of toner particles having a volume median diameter (Dv50) or less.

<Configuration and production method of toner base particles by emulsion polymerization aggregation method>
Hereinafter, the toner base particles produced by the emulsion polymerization aggregation method will be described in more detail. When a toner is produced by an emulsion polymerization aggregation method, it usually has a polymerization process, a mixing process, an aggregation process, an aging process, and a washing / drying process. That is, generally, a dispersion liquid containing primary polymer particles obtained by emulsion polymerization is mixed with a dispersion liquid such as a colorant, a charge control agent, and wax, and the primary particles in the dispersion liquid are aggregated to form core particles. Then, if necessary, the toner base particles can be obtained by washing and drying the particles obtained by fusing and adhering the resin fine particles or the like as necessary.

[Polymerization process]
As the binder resin constituting the polymer primary particles used in the emulsion polymerization aggregation method, one or more polymerizable monomers that can be polymerized by the emulsion polymerization method may be appropriately used. Examples of the polymerizable monomer include “a polymerizable monomer having an acidic group” (hereinafter sometimes simply referred to as “acidic monomer”), “a polymerizable monomer having a basic group” (hereinafter simply referred to as “basic monomer”). "Polymerizable monomer having a polar group" (hereinafter sometimes referred to simply as "polar monomer") and "polymerizability having neither an acidic group nor a basic group" It is preferable to use “monomer” (hereinafter sometimes referred to as “other monomer”) as a raw material polymerizable monomer. At this time, each polymerizable monomer may be added separately, or a plurality of polymerizable monomers may be mixed in advance and added simultaneously. Furthermore, it is also possible to change the polymerizable monomer composition during the addition of the polymerizable monomer. Further, the polymerizable monomer may be added as it is, or may be added as an emulsion prepared by mixing with water or an emulsifier in advance.

  Examples of the “acidic monomer” include polymerizable monomers having a carboxyl group such as acrylic acid, methacrylic acid, itaconic acid, maleic acid, fumaric acid and cinnamic acid, polymerizable monomers having a sulfonic acid group such as sulfonated styrene, vinyl Examples thereof include polymerizable monomers having a sulfonamide group such as benzenesulfonamide. Examples of the “basic monomer” include aromatic vinyl compounds having an amino group such as aminostyrene, and nitrogen-containing heterocyclic ring-containing polymerizable monomers such as vinylpyridine and vinylpyrrolidone.

  These polar monomers may be used alone or in combination, and may exist as a salt with a counter ion. Among these, it is preferable to use an acidic monomer, and (meth) acrylic acid is more preferable. The proportion of the total amount of polar monomers in 100% by mass of all polymerizable monomers constituting the binder resin as the polymer primary particles is preferably 0.05% by mass or more, more preferably 0.3% by mass or more, and particularly Preferably it is 0.5 mass% or more, More preferably, it is 1 mass% or more. The upper limit is preferably 10% by mass or less, more preferably 5% by mass or less, and particularly preferably 2% by mass or less. When it is in the above range, the dispersion stability of the obtained polymer primary particles is improved, and the particle shape and particle diameter can be easily adjusted in the aggregation step.

  “Other monomers” include styrenes such as styrene, methylstyrene, chlorostyrene, dichlorostyrene, p-tert-butylstyrene, pn-butylstyrene, pn-nonylstyrene, methyl acrylate, acrylic acid Acrylic esters such as ethyl, propyl acrylate, n-butyl acrylate, isobutyl acrylate, hydroxyethyl acrylate, ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, n-butyl methacrylate, methacryl Methacrylates such as isobutyl acid, hydroxyethyl methacrylate, ethylhexyl methacrylate, acrylamide, N-propylacrylamide, N, N-dimethylacrylamide, N, N-dipropylacrylamide, N N- dibutyl acrylamide, acrylic acid amide and the like. A polymerizable monomer may be used independently and may be used in combination of multiple.

  In the present invention, among the above-mentioned polymerizable monomers used in combination, as a preferred embodiment, an acidic monomer and other monomers may be used in combination. More preferably, (meth) acrylic acid is used as the acidic monomer, and a polymerizable monomer selected from styrenes and (meth) acrylic acid esters is used as the other monomer. It is preferable to use (meth) acrylic acid as the monomer, and to use a combination of styrene and (meth) acrylic acid esters as the other monomer, particularly preferably (meth) acrylic acid as the acidic monomer and other monomers. As a combination of styrene and n-butyl acrylate.

  Furthermore, it is also preferable to use a crosslinked resin as the binder resin constituting the polymer primary particles. In that case, a polyfunctional monomer having radical polymerizability is used as a crosslinking agent shared with the above polymerizable monomer. Examples of the multifunctional monomer include divinylbenzene, hexanediol diacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, neopentyl glycol dimethacrylate, neopentyl glycol acrylate, diallyl phthalate, and the like. Is mentioned. In addition, a polymerizable monomer having a reactive group in a pendant group such as glycidyl methacrylate, methylol acrylamide, acrolein or the like can be used as a crosslinking agent. Among them, radically polymerizable bifunctional monomers are preferable, and divinylbenzene and hexanediol diacrylate are particularly preferable.

  These crosslinking agents such as polyfunctional monomers may be used alone or in combination. When a crosslinked resin is used as the binder resin constituting the polymer primary particles, the blending ratio of the crosslinking agent such as a polyfunctional monomer in the total polymerizable monomer constituting the resin is preferably 0.005% by mass or more, More preferably, it is 0.1 mass% or more, More preferably, it is 0.3 mass% or more, Preferably it is 5 mass% or less, More preferably, it is 3 mass% or less, More preferably, it is 1 mass% or less. desirable.

  Known emulsifiers can be used for the emulsion polymerization, but one or more emulsifiers selected from cationic surfactants, anionic surfactants and nonionic surfactants are used in combination. be able to.

  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 the like.

  Examples of the anionic surfactant include fatty acid soaps such as sodium stearate and sodium dodecanoate, sodium dodecyl sulfate, sodium dodecylbenzenesulfonate, and sodium lauryl sulfate.

  Nonionic surfactants include, for example, polyoxyethylene dodecyl ether, polyoxyethylene hexadecyl ether, polyoxyethylene nonyl phenyl ether, polyoxyethylene lauryl ether, polyoxyethylene sorbitan monooleate ether, monodecanoyl sucrose, etc. Is mentioned.

  The amount of the emulsifier is usually 1 to 10 parts by mass with respect to 100 parts by mass of the polymerizable monomer, and these emulsifiers include, for example, partially or fully saponified polyvinyl alcohol such as saponified polyvinyl alcohol, hydroxy One type or two or more types of cellulose derivatives such as ethyl cellulose can be used in combination as a protective colloid.

  Examples of the polymerization initiator include hydrogen peroxide; persulfates such as potassium persulfate; organic peroxides such as benzoyl peroxide and lauroyl peroxide; 2,2′-azobisisobutyronitrile; Azo compounds such as 2′-azobis (2,4-dimethylvaleronitrile); redox initiators and the like are used. One or more of them are usually used in an amount of about 0.1 to 3 parts by mass with respect to 100 parts by mass of the polymerizable monomer. Among them, it is preferable that at least part or all of the initiator is hydrogen peroxide or organic peroxides.

  Moreover, 1 type, or 2 or more types of suspension stabilizers, such as a calcium phosphate, a magnesium phosphate, a calcium hydroxide, magnesium hydroxide, are usually 1-10 mass parts with respect to 100 mass parts of polymerizable monomers. It may be used.

  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 the emulsion polymerization, a known chain transfer agent can be used as necessary. Specific examples of such a chain transfer agent include t-dodecyl mercaptan, 2-mercaptoethanol, diisopropylxanthogen, four Examples thereof include carbon chloride and trichlorobromomethane. The chain transfer agent may be used alone or in combination of two or more, and is usually used in a range of 5% by mass or less based on the total polymerizable monomer. Moreover, a pH adjuster, a polymerization degree adjuster, an antifoaming agent, etc. can be further mix | blended with a reaction system suitably.

  In the emulsion polymerization, the polymerizable monomers are polymerized in the presence of a polymerization initiator, and the polymerization temperature is usually 50 to 120 ° C, preferably 60 to 100 ° C, and more preferably 70 to 90 ° C.

  The volume average diameter (Mv) of the polymer primary particles obtained by emulsion polymerization is usually 0.02 μm or more, preferably 0.05 μm or more, more preferably 0.1 μm or more, and usually 3 μm or less, preferably 2 μm or less. More preferably, the thickness is 1 μm or less. When the particle size is less than the above range, it may be difficult to control the aggregation rate. When the particle size exceeds the above range, the particle size of the toner obtained by aggregation tends to be large, and a toner having a target particle size can be obtained. It can be difficult.

  Tg by the DSC method of the binder resin as the polymer primary particles in the present invention is preferably 40 to 80 ° C, more preferably 55 to 65 ° C. Within this range, the storage stability is good and, in addition, the cohesiveness is not impaired. When Tg is too high, the cohesiveness is poor, and an aggregating agent must be added excessively or the aggregation temperature must be excessively increased. As a result, fine powder may be easily generated. Here, when the Tg of the binder resin overlaps with the caloric change based on other components, for example, the melting peak of polylactone or wax, it is not possible to make a clear judgment, and the toner was prepared in a state in which such other components were excluded. The Tg at the time is meant.

  In the present invention, the acid value of the binder resin constituting the polymer primary particles is not particularly limited, but is preferably 3 to 50 mgKOH / g, more preferably 5 to 30 mgKOH / g, as a value measured by the method of JISK-0070. It is good to be.

  The lower limit of the solid content concentration of the polymer primary particles in the “polymer primary particle dispersion” used in the present invention is preferably 14% by mass or more, and more preferably 21% by mass or more. On the other hand, the upper limit is preferably 30% by mass or less, and more preferably 25% by mass or less. When it is within the above range, it is easy to adjust the aggregation speed of the polymer primary particles empirically in the aggregation process, and as a result, the particle diameter, particle shape, and particle size distribution of the core particles can be easily adjusted to an arbitrary range. It becomes.

[Mixing process]
In the present invention, a dispersion containing polymer primary particles obtained by emulsion polymerization is mixed with a dispersion of a colorant, if necessary, a charge control agent, a wax or the like, and the primary particles in the dispersion are aggregated. It is preferable to obtain toner base particles by washing and drying the particles obtained by fusing them as core particles. Further, it is particularly preferable that toner base particles are obtained by washing and drying particles obtained by fixing or adhering resin fine particles, which will be described later, to the surface of the core particles and then fusing them.

  The colorant is not particularly limited as long as it is a commonly used colorant. Examples thereof include the pigments described above, carbon black such as furnace black and lamp black, and magnetic colorants. The content of the colorant may be an amount sufficient for the obtained toner to form a visible image by development. For example, the content is preferably in the range of 1 to 25 parts by mass in the toner, more preferably 1 to 15 parts by mass, particularly preferably 3 to 12 parts by mass.

The colorant may have magnetism, and examples of the magnetic colorant include a ferromagnetic material that exhibits ferrimagnetism or ferromagnetism in the vicinity of 0 to 60 ° C., which is a use environment temperature of a printer, a copying machine, and the like. Is, for example, magnetite (Fe ₃ O ₄ ), maghemite (γ-Fe ₂ O ₃ ), an intermediate or mixture of magnetite and maghemite, M _x Fe _3-x O ₄ , where M is Mg, Spinel ferrite such as Mn, Fe, Co, Ni, Cu, Zn, Cd, hexagonal ferrite such as BaO.6Fe ₂ O ₃ , SrO.6Fe ₂ O ₃ , Y ₃ Fe ₅ O ₁₂ , Sm ₃ Fe ₅ O garnet-type oxides such as _12, shown rutile oxides such as CrO _2, and, Cr, Mn, Fe, Co, the magnetic near 0 to 60 ° C. of such metal or their ferromagnetic alloys such as Ni Ones, and among them, magnetite, maghemite, or magnetite and maghemite intermediates are preferred.

  When it is contained from the viewpoint of scattering prevention, charge control, etc. while having the characteristics as a non-magnetic toner, the content of the magnetic powder in the toner is 0.2 to 10% by mass, preferably 0.5 to 0.5%. It is 8 mass%, More preferably, it is 1-5 mass%. When used as a magnetic toner, the content of the magnetic powder in the toner is usually 15% by mass or more, preferably 20% by mass or more, and usually 70% by mass or less, preferably 60% by mass or less. It is desirable. If the content of the magnetic powder is less than the above range, the magnetic force required for the magnetic toner may not be obtained, and if it exceeds the above range, it may cause poor fixing properties.

  As a blending method of the colorant in the emulsion polymerization aggregation method, usually, a polymer primary particle dispersion and a colorant dispersion are mixed to form a mixed dispersion, and then aggregated to obtain a particle aggregate. The colorant is preferably used in the state of being emulsified in water by a mechanical means such as a sand mill or a bead mill in the presence of an emulsifier. At this time, the colorant dispersion is preferably added with 10 to 30 parts by weight of the colorant and 1 to 15 parts by weight of the emulsifier with respect to 100 parts by weight of water. The particle diameter of the colorant in the dispersion is monitored while being dispersed, and the volume average diameter (Mv) is finally adjusted to 0.01 to 3 μm, more preferably 0.05 to It is preferable to control within the range of 0.5 μm. The blend of the colorant dispersion at the time of emulsion aggregation is calculated and used so as to be 2 to 10% by mass in the finished toner base particles after aggregation.

  It is preferable to add a wax to the toner used in the present invention in order to impart releasability. The wax may be contained in the polymer primary particles or in the resin fine particles. Any wax can be used as long as it has releasability, and is not particularly limited. Specifically, 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; water Plant waxes such as soy 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 aliphatic alcohols such as eicosanol; glycerin and pentaerythritol Examples include carboxylic acid esters or partial esters of polyhydric alcohols obtained from polyhydric alcohols such as polyhydric alcohols and long chain fatty acids; higher fatty acid amides such as oleic acid amides and stearic acid amides; low molecular weight polyesters and the like.

  In order to improve the fixability among these waxes, the melting point of the wax is preferably 30 ° C. or higher, more preferably 40 ° C. or higher, and particularly preferably 50 ° C. or higher. Moreover, 100 degrees C or less is preferable, 90 degrees C or less is still more preferable, and 80 degrees C or less is especially preferable. If the melting point is too low, the wax tends to be exposed and sticky after fixing, and if the melting point is too high, the fixability at low temperatures is poor. Furthermore, as the wax compound species, ester waxes obtained from aliphatic carboxylic acids and mono- or polyhydric alcohols are preferred, and ester waxes having 20 to 100 carbon atoms are preferred.

  The above 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 used is preferably 4 to 20 parts by mass, particularly preferably 6 to 18 parts by mass, and further preferably 8 to 15 parts by mass with respect to 100 parts by mass of the toner. The wax is contained in “polymer primary particles forming core particles” and / or “resin fine particles fixed or adhered to the surface of the core particles”, etc., but the above value is 100 parts by mass of the total toner obtained. The value of the total wax content, regardless of where it is contained.

  Usually, as the amount of wax used increases, the aggregation control deteriorates and the particle size distribution tends to be broad. Further, when the volume median diameter (Dv50) of the toner is 7 μm or less as in the present invention, that is, when the toner has a small particle size, the exposure of the wax to the toner surface is increased as the amount of wax used increases. May become extremely violent and toner storage stability may deteriorate. However, the toner of the present invention has a particle size distribution that does not cause deterioration of the toner characteristics as compared with conventional toners even when the amount of wax used is large as in the above range.

  As a method of blending the wax in the emulsion polymerization aggregation method, a wax dispersion that has been previously emulsified and dispersed in water at a volume average diameter (Mv) of 0.01 to 2.0 μm, more preferably 0.01 to 0.5 μm, is obtained during emulsion polymerization. It is preferable to add, or to add in an aggregation process. In order to disperse the wax with a suitable dispersed particle diameter in the toner, it is preferable to add the wax as a seed during emulsion polymerization. By adding as a seed, polymer primary particles in which wax is encapsulated can be obtained, so that a large amount of wax does not exist on the toner surface, and deterioration of chargeability and heat resistance of the toner can be suppressed. The wax content in the polymer primary particles is preferably 4 to 30% by mass, more preferably 5 to 20% by mass, and particularly preferably 7 to 15% by mass.

  Further, a wax may be contained in the resin fine particles described later, and in this case as well, it is preferable to add the wax as a seed during emulsion polymerization, as in the case of obtaining the polymer primary particles. The content ratio of the wax in the entire resin fine particles is preferably smaller than the content ratio of the wax in the entire polymer primary particles. Generally, when wax is contained in resin fine particles, the fixability is improved, but on the other hand, the generation amount of fine powder tends to increase. The reason for this is that the fixability is improved because the speed of movement of the wax to the toner surface is increased when heat is applied, but the inclusion of the wax in the resin fine particles broadens the particle size distribution of the resin fine particles. It is considered that the aggregation control becomes difficult, and as a result, an increase in fine powder is caused.

  In the toner used in the present invention, a charge control agent may be blended in order to impart charge amount and charge stability. Conventionally known compounds are used as the charge control agent. Examples thereof include hydroxycarboxylic acid metal complexes, azo compound metal complexes, naphthol compounds, naphthol compound metal compounds, nigrosine dyes, quaternary ammonium salts, and mixtures thereof. The blending amount of the charge control agent is preferably in the range of 0.1 to 5 parts by mass with respect to 100 parts by mass of the resin.

  When a charge control agent is contained in the toner in the emulsion polymerization aggregation method, the charge control agent is blended with a polymerizable monomer or the like at the time of emulsion polymerization, or is blended in the aggregation process with the polymer primary particles and the colorant. The blended primary particles, the colorant, and the like can be blended by a method such as blending after agglomeration to obtain an appropriate particle size as a toner. Of these, the charge control agent is preferably emulsified and dispersed in water using an emulsifier, and used as an emulsified dispersion having a volume average diameter (Mv) of 0.01 μm to 3 μm. The blend of the charge control agent dispersion at the time of emulsion aggregation is calculated and used so as to be 0.1 to 5% by mass in the finished toner base particles after aggregation.

  The volume average diameter (Mv) of polymer primary particles, resin fine particles, colorant particles, wax particles, charge control agent particles, etc. in the above dispersion is measured using a nanotrack by the method described in the examples. , Defined as its measured value.

[Aggregation process]
In the aggregation step in the emulsion polymerization aggregation method, the above-described primary polymer particles, resin fine particles, colorant particles, and charge components such as a charge control agent and wax are mixed at the same time or sequentially. It is possible to prepare a dispersion of the above components, that is, a polymer primary particle dispersion, a resin fine particle dispersion, a colorant particle dispersion, a charge control agent dispersion, and a wax fine particle dispersion. It is preferable from the viewpoint of uniformity.

  In addition, when mixing these different types of dispersions, the aggregation speed of the components contained in each dispersion is different. Are preferably mixed. Since the suitable time required for the addition varies depending on the amount of the dispersion to be mixed, the solid concentration, and the like, it is preferable to adjust appropriately. For example, when the colorant particle dispersion is mixed with the polymer primary particle dispersion, it is preferably added over 3 minutes. Also, when mixing the resin fine particle dispersion with the core particles, it is preferably added over 3 minutes.

  The agglomeration treatment includes a heating method, a method of adding an electrolyte, a method of reducing the concentration of an emulsifier in the system, a method of combining these, and the like. When primary particles are agglomerated under stirring to obtain particle agglomerates that are approximately the size of the toner, the particle size of the particle agglomerates is controlled from the balance between the agglomeration force between the particles and the shearing force due to agitation. However, the cohesive force can be increased by the above method.

As an electrolyte in the case of performing aggregation by adding an electrolyte, either an organic salt or an inorganic salt may be used. Specifically, NaCl, KCl, LiCl, Na ₂ SO ₄ , K ₂ SO ₄ , Li ₂ SO ₄ may be used. Inorganic salts having a monovalent metal cation such as CH ₃ COONa, C ₆ H ₅ SO ₃ Na; inorganic salts having a divalent metal cation such as MgCl ₂ , CaCl ₂ , MgSO ₄ , CaSO ₄ , ZnSO ₄ ; Examples thereof include inorganic salts having a trivalent metal cation such as Al ₂ (SO ₄ ) ₃ and Fe ₂ (SO ₄ ) ₃ . Among these, when an inorganic salt having a divalent or higher polyvalent metal cation is used, it is preferable in terms of productivity because the agglomeration speed is increased. On the other hand, the amount of polymer primary particles and the like that are not incorporated into the core particle is small. As a result, fine powder that does not reach the desired toner particle size is likely to be generated. Therefore, it is preferable to use an inorganic salt having a monovalent metal cation that does not have a strong aggregating action in terms of suppressing the amount of fine powder generated.

  The amount of the electrolyte used varies depending on the type of electrolyte, target particle size, and the like, but is usually 0.05 to 25 parts by mass, preferably 0.1 to 15 parts per 100 parts by mass of the solid component of the mixed dispersion. Part by mass, more preferably 0.1 to 10 parts by mass. When the amount used is less than the above range, the progress of the agglutination reaction is slow, and fine particles of 1 μm or less remain after the agglomeration reaction, or the average particle size of the obtained particle aggregate does not reach the target particle size. In the case of exceeding the above range, it tends to cause rapid agglomeration, making it difficult to control the particle diameter, and may cause problems such as inclusion of coarse powder or amorphous particles in the obtained core particles. is there.

  In addition, it is preferable that the electrolyte is added not intermittently but intermittently or continuously over a certain period of time. The addition time varies depending on the amount used, but is preferably added over 0.5 minutes. Usually, when an electrolyte is added, abrupt aggregation starts as soon as the electrolyte is added, so that there is a tendency that a large amount of polymer primary particles, colorant particles, aggregates, and the like left behind in the aggregation remain. These are considered to be one of the sources of fine powder. According to the above operation, uniform agglomeration can be performed without abrupt agglomeration, so that generation of fine powder can be prevented.

  Moreover, 20-70 degreeC is preferable and, as for the final temperature of the aggregation process in the case of performing aggregation by adding electrolyte, 30-60 degreeC is more preferable. Here, controlling the temperature before the aggregation step is one of the methods for controlling the toner base particles to a specific range of particle sizes. Some colorants added to the aggregating step induce aggregation, such as the above-described electrolyte, and sometimes agglomerate without adding an electrolyte. Therefore, the aggregation can be prevented by cooling the temperature of the polymer primary particle dispersion in advance when mixing the colorant dispersion. This aggregation causes fine powder to be generated. In the present invention, the polymer primary particles are preferably cooled in advance in a range of preferably 0 to 15 ° C, more preferably 0 to 12 ° C, and still more preferably 2 to 10 ° C. Note that this method is not effective only when the electrolyte is added to perform aggregation, and the aggregation is performed without adding an electrolyte, such as a method of controlling the pH or adding a polar organic solvent such as alcohol to perform the aggregation method. The method is also used, and is not particularly limited to the aggregation method.

  The final temperature of the agglomeration step in the case of agglomeration by heating is usually a temperature range of (Tg-20 ° C) to Tg of the polymer primary particles, and a range of (Tg-10 ° C) to (Tg-5 ° C). It is preferable that

  In addition, as a method for preventing abrupt aggregation in order to prevent generation of fine powder, there is a method of adding demineralized water or the like. The method of adding demineralized water or the like is not a method that is actively employed in terms of production efficiency because the coagulation action is not so strong as compared with the method of adding electrolyte, but rather, a large amount of filtrate is used in the subsequent filtration step or the like. Since it will be obtained, it may be unpreferable. However, it is very effective when fine aggregation control is required as in the toner of the present invention. Moreover, in this invention, it is preferable to employ | adopt in combination with the method of adding the said heating method, the method of adding electrolyte, etc. At this time, the method of adding demineralized water after adding the electrolyte is particularly preferable in that the aggregation is easily controlled.

  The time required for agglomeration is optimized by the shape of the apparatus and the processing scale. In order to reach the target particle size of the toner base particles, the temperature at which the aggregation process is completed, for example, the emulsifier It is preferable that the time from a temperature 8 ° C. lower than the temperature during the operation of stopping the growth of the core particles by addition, pH control, etc. (hereinafter abbreviated as “aggregation final temperature”) to the aggregation final temperature is 30 minutes or more. More preferably, it is 1 hour or more. The polymer core particles, colorant particles, or aggregates thereof remaining by extending the time are not left behind, but are taken into the target core particles or agglomerate with each other, so that the target core is obtained. Become particles.

  In the present invention, the toner base particles can be formed by coating (adhering or fixing) resin fine particles on the surface of the core particles as necessary. The volume average diameter (Mv) of the resin fine particles is preferably 0.02 μm to 3 μm, more preferably 0.05 μm to 1.5 μm. In general, the use of the resin fine particles promotes the generation of fine powder that does not reach a predetermined toner particle size. Therefore, the toner coated with the conventional resin fine particles increases in the amount of fine powder that does not satisfy the predetermined toner particle size.

  As the resin fine particles, those obtained by polymerizing a polymerizable monomer similar to the polymerizable monomer used for the above-mentioned polymer primary particles can be used, and among them, a cross-linkage containing a polyfunctional monomer as a raw material. Resins are preferred. The resin fine particles preferably do not contain polylactone and wax. The resin fine particles are usually used as a dispersion liquid dispersed in water or a liquid mainly composed of water with an emulsifier. However, when the charge control agent is added after the aggregation treatment, the resin fine particles are charged into the dispersion liquid containing the particle aggregates. It is preferable to add the resin fine particles after adding the control agent.

  In the present invention, a dispersion liquid containing polymer primary particles obtained by emulsion polymerization is mixed with a dispersion liquid such as a colorant, a charge control agent, and wax, and the primary particles in the dispersion liquid are aggregated to form core particles. It is particularly preferable to obtain toner base particles by washing and drying the particles obtained by fixing or adhering resin fine particles or the like to the surface of the core particles and then fusing them.

  The ratio of the resin fine particles to the whole core particles is preferably 0.5 to 30 parts by weight, particularly preferably 5 to 20 parts by weight with respect to 100 parts by weight of the core particles.

  The resin fine particles may be produced by the same method as the above polymer primary particles, and the structure thereof is not particularly limited, but the polar monomer occupies in 100% by mass of the total polymerizable monomer constituting the binder resin as the resin fine particles. The ratio of the total amount is preferably 0.05% by mass or more, more preferably 0.1% by mass or more, and further preferably 0.2% by mass or more. The upper limit is preferably 3% by mass or less, more preferably 1.5% by mass or less. When it is in the above range, the dispersion stability of the obtained resin fine particles is improved, and it becomes easy to adjust the particle shape and particle diameter in the aggregation process.

  Further, the proportion of the total amount of polar monomers in 100% by mass of the total polymerizable monomer constituting the binder resin as the resin fine particles is in 100% by mass of the total polymerizable monomer constituting the binder resin as the polymer primary particle. It is preferable that the ratio is smaller than the ratio of the total amount of polar monomers in view of easy adjustment of the particle shape and particle diameter in the aggregation process, generation of fine powder can be suppressed, and excellent charging characteristics.

  In addition, the Tg of the binder resin as the resin fine particles is preferably higher than the Tg of the binder resin as the polymer primary particles from the viewpoint of storage stability and the like.

[Aging process]
In the emulsion polymerization aggregation method, in order to increase the stability of the particle aggregate obtained by aggregation, an emulsifier and a pH adjuster are added as a dispersion stabilizer to reduce the aggregation force between the particles, thereby growing the toner base particles. It is preferable to add an aging step for causing fusion between the agglomerated particles after stopping.

  Here, as a method of controlling the particle size within a specific range, which means that the particle size distribution is sharp in the small particle size toner region of the present invention, the stirring rotation speed is reduced before the step of adding an emulsifier or a pH adjuster. A method of reducing the shearing force by stirring.

  In the ripening step, the viscosity of the binder resin is lowered by heating to be circularized, but if heated as it is, the growth of the toner base particle size does not stop, so for the purpose of stopping the particle size growth by heating, usually as a dispersion stabilizer In addition, a method of applying a shearing force by adding an emulsifier or a pH adjusting agent or increasing a stirring rotational speed has been adopted. However, the present inventors have found that these methods result in a state in which the aggregated particles in the dispersion are overdispersed, and rather, the particles that have been collected so far have partially collapsed to generate fine particles. Dispersion stabilizer is not used when manufacturing toner with a particle size, and is a "method of reducing shearing force on aggregated particles by lowering the rotational speed of stirring acting in the direction of promoting particle size growth of aggregated particles" By carrying out before the step of adding, the collapse of the aggregated particles is not promoted, and the coarsening of the aggregated particles can be suppressed, and the particle size distribution of the present invention can be achieved.

  For example, as an example, the toner having a specific particle size distribution of the present invention can be obtained by the above-described method. More specifically, the content of fine powder particles can be adjusted by the degree to which the rotational speed is reduced. For example, when the stirring rotation speed is decreased from 250 rpm to 220 rpm, a toner having a small particle size with a sharper particle size distribution than that of a known toner can be provided, and the toner having a specific particle size distribution of the present invention can be obtained.

  Even before the step of adding the dispersion stabilizer, the toner having a specific particle size distribution of the present invention can be obtained by reducing the stirring rotational speed and reducing the shearing force to the aggregated particles. In consideration of the point that the blending amount of the stabilizer can be adjusted, it is preferable to perform it before the step of adding the dispersion stabilizer.

  The temperature of the aging step is preferably not less than Tg of the binder resin constituting the primary particles, more preferably not less than 5 ° C higher than the Tg, and preferably not more than 80 ° C higher than the Tg, more preferably The temperature is 50 ° C. or higher than Tg. The time required for the aging step varies depending on the shape of the target toner, but after reaching the glass transition temperature of the polymer constituting the primary particles, usually 0.1 to 10 hours, preferably 1 to 6 hours. It is desirable to hold.

  In the emulsion polymerization aggregation method, it is preferable to add an emulsifier or raise the pH value of the aggregate liquid after the above aggregation process, preferably before the aging process or during the aging process. As the emulsifier used here, one or more kinds of emulsifiers that can be used when producing the polymer primary particles can be selected and used, and particularly used when the polymer primary particles are produced. It is preferable to use the same emulsifier.

  The blending amount in the case of blending the emulsifier is not limited, but is preferably 0.1 parts by weight or more, more preferably 1 part by weight or more, further preferably 3 parts by weight or more with respect to 100 parts by weight of the solid component of the mixed dispersion. Moreover, 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 an emulsifier or by increasing the pH value of the flocculation liquid, aggregation of the particle aggregates aggregated in the aggregation process can be suppressed. The generation of coarse particles in the toner can be suppressed.

  In the present invention, when the amount of the wax is increased, the high temperature fixability is improved, but the wax tends to be exposed on the toner surface, so that the chargeability and heat resistance may be deteriorated. The deterioration of performance can be prevented by coating with resin fine particles not containing.

  However, when the resin fine particles contain wax for the purpose of improving the high-temperature fixability, the resin fine particles once attached to the surface of the core particles are easily peeled off. This is because the particle size distribution of the resin fine particles described above becomes wide, and there are large particle size resin fine particles with weak adhesion. Therefore, in order to reduce the peeling off, it is preferable to raise the temperature while adding an aqueous solution in which a dispersion stabilizer and water are mixed in advance in a liquid in which particles having resin fine particles attached to the surface are dispersed. .

  When the “step of starting the temperature rise after the addition of the emulsifier” is adopted, that is, when the maturation step is performed after the cohesive force is sharply reduced, the resin fine particles once adhered due to the rapid decrease in the cohesive force. It may be easy to leave. Therefore, it is preferable to fuse the resin fine particles after adhering them without significantly reducing the cohesive force and suppressing the particle diameter growth.

  Here, in the small particle size toner of the present invention, as a method for controlling the particle size within the specific range (a particle size distribution satisfying the formula (1)) which means that the particle size distribution is sharp, an emulsifier or pH is used. An example is a method in which the number of rotations of stirring is reduced before the step of adding the adjusting agent, that is, the shearing force by stirring is reduced. This method is preferably employed when a system having a weak aggregating action, such as an emulsifier or a pH adjuster, is added at a time to rapidly shift to a stable (dispersed) system. As described above, if a method of raising the temperature while adding an aqueous solution in which a dispersion stabilizer and water are mixed in advance is adopted, the system is too inclined to agglomerate when the stirring rotation speed is lowered, so that the particle size May lead to enlargement.

As an example, the toner having a specific particle size distribution according to the present invention can be obtained by the above-described method. More specifically, the content of fine powder particles can be adjusted by the degree to which the rotational speed is reduced. For example, when the stirring rotational speed is decreased from 250 rpm to 150 rpm, a toner having a small particle size with a sharper particle size distribution than that of a known toner can be provided, and the toner having a specific particle size distribution of the present invention can be obtained. However, this value is naturally
(A) The diameter of the stirring vessel (as a so-called general cylindrical shape) and the maximum diameter of the stirring blade (and its relative ratio)
(B) Height of the stirring vessel (c) Peripheral speed at the tip of the stirring blade (d) Shape of the stirring blade (e) Vary depending on conditions such as the position of the blade in the stirring vessel. About special (c), 1.0-2.5 m / sec is preferable, 1.2-2.3 m / sec is more preferable, 1.5-2.2 m / sec is especially preferable. This is because, within the above range, a suitable shear rate that does not peel off and does not enlarge is given to the particles.

  The temperature of the aging step is preferably not less than Tg of the binder resin as the polymer primary particles, more preferably not less than 5 ° C higher than the Tg, and preferably not more than 80 ° C higher than the Tg, more preferably The temperature is 50 ° C. or higher than the Tg. The time required for the aging step varies depending on the shape of the target toner, but after reaching the glass transition temperature of the polymer constituting the polymer primary particles, usually 0.1 to 5 hours, preferably 1 to It is desirable to hold for 3 hours.

  By such a heat treatment, the polymer primary particles in the aggregate are fused and integrated, and the shape of the toner base particles 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 an aging process, by controlling the temperature and time of the aging process, the shape of the polymer primary particles is agglomerated, a potato type with advanced fusion, a spherical form with further fusion For example, various shapes of toner can be manufactured according to the purpose.

[Washing and drying process]
The particle aggregate obtained through each of the above steps is subjected to solid / liquid separation according to a known method, the particle aggregate is recovered, then washed as necessary, and then dried. Toner mother particles can be obtained.

  Further, an outer layer mainly composed of a polymer is further formed on the surface of the particles obtained by the emulsion polymerization aggregation method by, for example, a spray drying method, an in-situ method, or a submerged particle coating method. It is also possible to obtain encapsulated toner base particles by forming them with a thickness of preferably 0.01 to 0.5 μm.

<Physical properties and shape of toner base particles>
Further, in the emulsion polymerization aggregation method toner, the average circularity measured using a flow type particle image analyzer FPIA-2100 is preferably 0.90 or more, more preferably 0.92 or more, and further preferably 0.94 or more. It is. It is considered that the closer to a sphere, the less the charge amount is localized in the particles, and the developability tends to be uniform. However, making a perfect spherical toner deteriorates the cleaning property, so the average circularity Is preferably 0.98 or less, more preferably 0.97 or less. The average circularity is measured and defined by the method described in the examples.

  In addition, at least one of the peak molecular weights in the gel permeation chromatography (hereinafter sometimes abbreviated as “GPC”) of the tetrahydrofuran (THF) soluble content of the toner is preferably 30,000 or more, more preferably 40,000. More preferably, it is 50,000 or more, preferably 200,000 or less, more preferably 150,000 or less, and still more preferably 100,000 or less. When the peak molecular weight is lower than the above range, the mechanical durability in the non-magnetic one-component development method may be deteriorated. When the peak molecular weight is higher than the above range, the low temperature fixability and the fixing strength are deteriorated. There is a case.

  The THF-insoluble content of the toner is preferably 10% by mass or more, more preferably 20% by mass or more, and preferably 60% by mass or less, more preferably when measured by a weight method using Celite filtration. It is good that it is 50 mass% or less. If it is not within the above range, it may be difficult to achieve both mechanical durability and low-temperature fixability.

  The chargeability of the emulsion polymerization aggregation method toner may be positively charged or negatively charged, but is preferably used as a negatively chargeable toner. Control of the chargeability of the toner can be adjusted by selection and content of the charge control agent, selection and blending amount of the external additive, and the like.

<Pulverized toner>
The method for producing a pulverized toner having a particle size in the specific range of the present invention is not particularly limited, and examples thereof include a method of excessive classification.

  The resin used for producing the pulverized toner may be appropriately selected from those known to be usable for toner. For example, styrene resin, vinyl chloride resin, rosin modified maleic acid resin, phenol resin, epoxy resin, saturated or unsaturated polyester resin, ionomer resin, polyurethane resin, silicone resin, ketone resin, ethylene-acrylate copolymer, xylene Resin, polyvinyl butyral resin, etc. are used. These resins can be used alone or in combination.

  The polyester resin used in the present invention comprises a polyhydric alcohol and a polybasic acid, and at least one of these polyhydric alcohol and polybasic acid contains a trifunctional or higher polyfunctional component (crosslinking component) as necessary. It is obtained by polymerizing a polymerizable monomer composition. In the above, examples of the divalent alcohol used for the synthesis of the polyester resin include ethylene glycol, diethylene glycol, triethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, and neopentyl. Diols such as glycol, 1,4-butenediol, 1,5-pentanediol, 1,6-hexanediol, bisphenol A, hydrogenated bisphenol A, polyoxyethylenated bisphenol A, polyoxypropylenated bisphenol A, etc. Bisphenol A alkylene oxide adducts and others can be mentioned. Among these monomers, it is particularly preferable to use a bisphenol A alkylene oxide adduct as the main component monomer, and among them, an adduct having an average addition number of alkylene oxide of 2 to 7 per molecule is preferable.

  Examples of trihydric or higher polyhydric alcohols involved in the crosslinking of polyester include sorbitol, 1,2,3,6-hexanetetrol, 1,4-sorbitan, pentaerythritol, dipentaerythritol, tripentaerythritol, and sucrose. 1,2,4-butanetriol, 1,2,5-pentanetriol, glycerol, 2-methylpropanetriol, 2-methyl-1,2,4-butanetriol, trimethylolethane, trimethylolpropane, 1, Mention may be made of 3,5-trihydroxymethylbenzene and others.

  On the other hand, examples of the polybasic acid include maleic acid, fumaric acid, citraconic acid, itaconic acid, glutaconic acid, phthalic acid, isophthalic acid, terephthalic acid, cyclohexanedicarboxylic acid, succinic acid, adipic acid, sebacic acid, azelaic acid, malon. Examples thereof include acids, anhydrides of these acids, lower alkyl esters, alkenyl succinic acids such as n-dodecenyl succinic acid and n-dodecyl succinic acid, alkyl succinic acids, and other divalent organic acids.

  Examples of the tribasic or higher polybasic acid involved in the crosslinking of polyester include 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, 1,2,4-cyclohexanetricarboxylic acid, 2, 5,7-naphthalenetricarboxylic acid, 1,2,4-naphthalenetricarboxylic acid, 1,2,5-hexanetricarboxylic acid, 1,3-dicarboxyl-2-methyl-2-methylenecarboxypropane, tetra (methylenecarboxyl) Mention may be made of methane, 1,2,7,8-octanetetracarboxylic acid and anhydrides thereof.

  These polyester resins can be synthesized by a usual method. Specifically, conditions such as reaction temperature (170 to 250 ° C.), reaction pressure (5 mmHg to normal pressure) and the like are determined according to the reactivity of the monomer, and the reaction is terminated when predetermined physical properties are obtained. . The Sp of the polyester resin according to the present invention is preferably 90 to 135 ° C, and more preferably 95 to 133 ° C among them. The range of Tg is, for example, 50 to 65 ° C. when the softening point is 90 ° C., and 60 to 75 ° C. when the softening point is 135 ° C. In this case, when Sp is lower than the above range, an offset phenomenon at the time of fixing is likely to occur. When Sp is higher than the above range, the fixing energy increases, and color toner tends to deteriorate glossiness and transparency. . Further, when Tg is lower than the above range, toner agglomerates and fixation are likely to occur, and when Tg is higher than the above range, the fixing strength at the time of thermal fixing tends to be low, such being undesirable. Sp can be adjusted mainly by the molecular weight of the resin. When the tetrahydrofuran soluble content of the resin is measured by the GPC method, the number average molecular weight is preferably 2000 to 20000, and more preferably 3000 to 12000. Further, Tg can be adjusted mainly by selecting a monomer component constituting the resin. Specifically, Tg can be increased by using an aromatic polybasic acid as a main component as an acid component. That is, among the polybasic acids described above, phthalic acid, isophthalic acid, terephthalic acid, 1,2,4-benzenetricarboxylic acid, 1,2,5-benzenetricarboxylic acid, and the like, anhydrides thereof, lower alkyl esters, etc. It is desirable to use it as a main component.

In the present invention, Sp is defined as a value measured using a flow tester described in JIS K7210 and K6719. Specifically, using a flow tester (CFT-500, manufactured by Shimadzu Corporation), a plunger having an area of 1 cm ² while heating a sample of about 1 g at a preheating time of 50 ° C. for 5 minutes and a heating rate of 3 ° C./min. A load of 30 kg / cm ² is applied by pushing through a die having a hole diameter of 1 mm and a length of 10 mm. Thus, a plunger stroke-temperature curve is drawn, and when the height of the S-shaped curve is h, the temperature corresponding to h / 2 is defined as the softening point. Moreover, the measurement of Tg is defined as what was measured in accordance with the conventional method using the differential scanning calorimeter (DSC7 by Perkin-Elmer company, or DSC120 by Seiko Electronics Co., Ltd.).

  In general, when the acid value of the polyester resin is too high, it is difficult to obtain a stable high charge amount, and the charge stability at high temperature and high humidity tends to deteriorate. Therefore, in the present invention, the acid value is 50 KOHmg / g. It is preferable to adjust to the following, more preferably 30 KOH mg / g or less, and most preferably 3 to 15 KOH mg / g. As a method for adjusting the acid value within the above range, in addition to a method of controlling the blending ratio of alcohol-based and acid-based monomers used at the time of resin synthesis, for example, the acid monomer component is previously converted into a lower alkyl ester by transesterification. Examples include a method of synthesizing using an acid group and a method of neutralizing residual acid groups by blending a basic component such as an amino group-containing glycol in the composition. It goes without saying that can be adopted. In the present invention, the acid value of the polyester resin is measured according to the method of JIS K0070. However, when the resin is difficult to dissolve in the solvent, a good solvent such as dioxane is used.

The polyester resin is represented by the following formulas (a) to (d) when the glass transition temperature (Tg) is plotted as an x-axis variable and the softening point (Sp) is plotted as a y-axis variable on the xy coordinates. Those having physical properties within a range surrounded by a straight line are preferred. The unit of Tg and Sp is “° C.”.
Formula (a) Sp = 4 * Tg-110
Formula (b) Sp = 4 * Tg-170
Formula (c) Sp = 90
Formula (d) Sp = 135

  When the polyester resin having the physical properties surrounded by the straight lines represented by the above formulas (a) to (d) is used for the pulverized toner, the pulverized toner is extremely resistant to mechanical stress and is continuously used. In some cases, the toner can be prevented from aggregating or solidifying due to frictional heat generated, and appropriate chargeability can be maintained over a long period of time.

  The pulverized toner is not particularly limited as long as it is a commonly used colorant. For example, the colorant used for the above-described polymerized toner can be used. The content of the colorant may be an amount sufficient for the obtained toner to form a visible image by development. For example, the content is preferably in the range of 1 to 25 parts by weight in a toner similar to the polymerized toner. More preferably, it is 1 to 15 parts by weight, particularly preferably 3 to 12 parts by weight.

  The pulverized toner may contain other constituent materials. For example, all known charge control agents can be used. For example, there are nigrosine dyes, amino group-containing vinyl copolymers, quaternary ammonium salt compounds, polyamine resins and the like for positive chargeability, and those containing metals such as chromium, zinc, iron, cobalt and aluminum for negative chargeability. Metal azo dyes, salts of salicylic acid or alkylsalicylic acid with the aforementioned metals, metal complexes and the like are known. As a usage-amount, 0.1-25 weight part is good with respect to 100 weight part of resin, More preferably, 1-15 weight part is good. In this case, the charge control agent may be blended in the resin, or may be used in a form adhered to the surface of the toner base particles.

  Among these charge control agents, taking into account the charge imparting ability for the toner and color toner adaptability (the charge control agent itself is colorless or light color and has no color disturbance to the toner), it is an amino group for positive chargeability. Preferred are vinyl-containing copolymers and / or quaternary ammonium salt compounds. For negative chargeability, metal salts and metal complexes of salicylic acid or alkylsalicylic acid with chromium, zinc, aluminum, boron, etc. are preferred.

  Among these, examples of the amino group-containing vinyl copolymer include copolymer resins of amino acrylates such as N, N-dimethylaminomethyl acrylate and N, N-diethylaminomethyl acrylate and styrene and methyl methacrylate. Examples of the quaternary ammonium salt compound include tetraethylammonium chloride, a salt-forming compound of benzyltributylammonium chloride and naphtholsulfonic acid, and the like. For the positively chargeable toner, the above amino group-containing vinyl copolymer and the quaternary ammonium salt compound may be blended alone or in combination.

  As the metal salt and metal complex of salicylic acid or alkyl salicylic acid, among various known substances, chromium, zinc or boron complex of 3,5-ditertiary butyl salicylic acid is particularly preferable. Further, the above colorant and charge control agent may be subjected to a preliminary dispersion treatment, so-called master batch treatment, by pre-kneading with a resin in advance in order to improve dispersibility and compatibility in the toner.

  The pulverized toner preferably contains at least one fine particle additive on the surface of the particles. These are mainly intended to improve the adhesiveness, cohesiveness, fluidity and the like of the toner base particles, and improve the triboelectric chargeability and durability of the toner. Specific examples include organic and inorganic fine particles whose surface may have an average primary particle diameter of 0.001 to 5 μm, particularly preferably 0.002 to 3 μm, such as polyvinylidene fluoride and polytetrafluoroethylene. Fluorine resin powder such as zinc stearate, fatty acid metal salt such as calcium stearate, resin beads mainly composed of polymethyl methacrylate and silicone resin, minerals such as talc and hydrotalcite, silicon oxide, aluminum oxide And metal oxides such as titanium oxide, zinc oxide, and tin oxide.

Among these, silicon oxide fine particles (silica) are more preferable, and silicon oxide fine particles whose surfaces have been subjected to a hydrophobic treatment are particularly desirable. Examples of the hydrophobizing method include a method in which silicon oxide fine particles and organic silicon compounds such as hexamethyldisilazane, trimethylsilane, dimethyldichlorosilane, and silicone oil are reacted or physically adsorbed and chemically treated. . The BET specific surface area is preferably in the range of 20 to ²⁰⁰ m ² / g. The mixing ratio of these fine particle additives to the pulverized toner is preferably in the range of 0.01 to 10% by mass, more preferably 0.05 to 5% by mass, based on the whole toner base particles.

  In the pulverized toner according to the present invention, any other known substance such as a low-melting-point release agent such as low molecular weight polyalkylene, paraffin wax, ester wax, or the like can be contained as other constituent components.

Examples of the method for producing a pulverized toner having a specific particle size distribution of the present invention include the following.
1. Resin, charge control substance, colorant and additives added as necessary are uniformly dispersed with a Henschel mixer or the like.
2. The dispersion is melt-kneaded with a kneader, an extruder, a roll mill or the like.
3. The kneaded product is roughly pulverized with a hammer mill, a cutter mill or the like, and then finely pulverized with a jet mill, an I-type mill or the like.
4). The finely pulverized product is classified with a dispersion classifier, a zigzag classifier or the like.
5). An external additive such as silica is dispersed in the classified product with a Henschel mixer or the like.

  In particular, the above 4. The toner for developing an electrostatic charge image of the present invention can be produced by a pulverization method by performing the classification until the specific particle size distribution of the present invention is obtained.

The pulverized toner of the present invention thus obtained is extremely resistant to mechanical stress, and it is also possible to avoid toner aggregation and solidification due to frictional heat generated during continuous use. It is particularly suitable as a toner for a non-magnetic one-component developing system because it can maintain an appropriate chargeability for a long period of time.

<Suspension polymerization method>
The method for producing a suspension polymerization method toner having a particle size distribution in a specific range of the present invention is not particularly limited. For example, the chemical structure such as the number of polar groups of the binder polymer, the molecular weight distribution, and the suspension state are improved. It is carried out by adjusting the kind and amount of the additive to be added, the stirring strength during suspension polymerization, the method for adding the polymerizable monomer, the kind and amount of the polymerization initiator and chain transfer agent, the polymerization temperature, the degree of classification, and the like.

  Examples of the raw material such as resin used in producing the suspension polymerization toner include those described in the emulsion polymerization aggregation method.

<Chemical grinding method represented by melt suspension method>
A method for producing a toner having a particle size distribution in a specific range of the present invention by a chemical pulverization method typified by a melt suspension method is not particularly limited. For example, the type of binder polymer, chemical structure, molecular weight distribution, etc. The kind and amount of the water additive that makes the suspended state good; the stirring strength at the time of addition of the polymer solution, the addition method, the temperature, etc .; if necessary, the degree of classification is adjusted.

  Examples of the resin used when the toner is manufactured by a chemical pulverization method such as a melt suspension method include those described in the section of the pulverization method. Other materials include those described in the emulsion polymerization aggregation method.

[Particle size distribution of toner base particles]
The toner of the present invention is a toner used in an electrostatic charge image developing method for cleaning a transfer residual toner with a cleaning blade, and has a volume median diameter (Dv50) of 4.0 μm or more and 7.0 μm or less, and It is essential that the relationship between the volume median diameter (Dv50) and the number% (Dns) of the toner having a particle diameter of 2.00 μm to 3.56 μm satisfies the following formula (1).
(1) Dns ≦ 0.233EXP (17.3 / Dv50)
[In the formula, Dv50 represents the volume median diameter (μm) of the toner, and Dns represents the number% of the toner having a particle diameter of 2.00 μm to 3.56 μm. ]

  The volume median diameter (Dv50) and Dns of the toner are measured by the method described in the Examples and are defined as those measured. In the present invention, the “toner” is obtained by blending the “toner base particles” with an external additive described later. Since the above Dv50 or the like is the Dv50 or the like of the “toner”, the “toner” is naturally measured as a measurement sample. However, measurement of the toner base particles before external addition gives substantially the same volume median diameter (Dv50) as that of the toner, so that the toner satisfying the above formula (1) is not only the toner but also the toner base particles. This case is also included in the present invention. Further, in a wet method toner such as an emulsion polymerization aggregation method, a dispersion in a state before filtration and drying is measured by dispersing in a dispersion medium Isoton II so that a dispersoid concentration is 0.03% by mass. However, since substantially the same Dv50 as that of the toner is provided, the toner satisfying the above formula (1) is also included in the present invention when the toner base particles are in the state of dispersion before filtration and drying.

Further, a toner in which the relationship between Dv50 and Dns satisfies the following formula (2) is preferable.
(2) Dns ≦ 0.110EXP (19.9 / Dv50)

  In Expression (1), if “Dns” on the left side is larger than the right side, that is, the amount of coarse powder in a specific region is large, image contamination or the like may occur.

Furthermore, a toner in which the relationship between Dv50 and Dns satisfies the following formula (3) is preferable.
(3) 0.0517EXP (22.4 / Dv50) ≦ Dns

  When Dns satisfies the above formula (1), the effect of the present invention is achieved, and when the condition (2) and / or (3) is satisfied, a more remarkable effect is achieved to solve the problems of the present invention. it can. In the formulas (1), (2), and (3), “EXP” indicates “Exponential”. That is, the base of the natural logarithm, and the right side is the exponent.

  Dv50 is 4.0 μm or more and 7.0 μm or less. Within this range, a high-quality image can be sufficiently provided. The said effect is show | played more that it is 6.8 micrometers or less. Moreover, it is preferable that it is 5.0 micrometers or more at the point which reduces the generation amount of a fine powder, and it is more preferable that it is 5.4 micrometers or more. Further, a toner having a Dns of 6% by number or less is preferable in that it provides a higher quality image and hardly contaminates the image forming apparatus. Further, it is more preferable that the above-mentioned conditions of “Formula (1) to Formula (3)”, “Dv50 is 5.0 μm or more” and / or “Dns is 6% by number or less” are satisfied in combination.

  Further, a value obtained by dividing “the BET specific surface area of the toner”, which will be described later, by “a spherical assumed specific surface area calculated from the volume median diameter (Dv50) of the toner” satisfies a specific condition. The toner of the present invention satisfying the particle size and particle size distribution can reduce consumption, obtain high image quality, prevent cleaning failure in a cleaning process using a cleaning blade, filming on an electrophotographic photosensitive member, The adhesion and accumulation of toner components on the charging roller, charging brush and the like are prevented, toner scattering is suppressed, and image defects do not occur. In addition, since the particle size distribution is sharp, the distribution of the behavior of each particle in the development process and transfer process (due to electric force, physical adhesion, and interstitial force) is small, and a good image with less scattering can be provided. .

  Further, when the toner having the particle size distribution is used, an image forming method in which the transfer residual toner is difficult to pass through between the electrostatic charge image holding member and the cleaning blade in combination with the cleaning blade can be realized. Further, the transfer efficiency is also increased for the same reason. Particles with a small charge amount do not cause smearing of the white background of the image or scatter and stain the inside of the apparatus, and particles with a large charge amount adhere to members such as a layer regulating blade or a roller without being developed. And image defects such as blurring are not caused.

  In order to obtain a toner satisfying the above formula (1), it is preferable to employ an operation in which the aggregation speed is not high compared with the operation normally performed in the aggregation step. Examples of operations that do not cause the aggregation speed to be high include, for example, cooling the dispersion to be used in advance, adding the dispersion over time, adopting an electrolyte that does not have a large aggregating action, continuously using the electrolyte, or There are methods such as intermittent addition, slowing the rate of temperature rise, and long aggregation time. In the aging step, it is preferable to adopt an operation in which the aggregated particles are difficult to redisperse. Examples of the operation in which the agglomerated particles are difficult to finely disperse include, for example, a method in which the number of revolutions for stirring is decreased, a dispersion stabilizer is added continuously or intermittently, and a dispersion stabilizer and water are mixed in advance.

  The toner satisfying the above formula (1) is a step of removing a part of particles having a volume median diameter (Dv50) or less from the finally obtained toner or toner base particles by an operation such as classification. It is preferable for the purpose of simplifying the process. The particle size distribution in the present invention can be obtained without performing an operation such as classification.

  Regarding the reason why the particle size% (Dns) is specified to be 2.00 μm or more and 3.56 μm or less, the lower limit is the measurement limit of the apparatus used for measuring the toner particle size of the present invention. The upper limit value is a critical value of the effect obtained from the results described in the examples. That is, when the number% of the toner having a particle size larger than 3.56 μm is employed, the toner that exhibits the effect of the present invention and the toner that does not exhibit the effect cannot be clearly distinguished by a formula.

  The toner of the present invention having the particle size distribution obtained by the above method has a very sharp charge amount distribution as compared with the conventional toner. The charge amount distribution has a correlation with the particle size distribution of the toner. When the toner has a broad particle size distribution like a conventional toner, the charge amount distribution is also broad. When the charge amount distribution becomes broad, the ratio of particles with low charge or particles with high charge that cannot be controlled by the developing conditions of the toner device increases, causing various image defects. For example, particles with a small charge amount cause stains on the white background of the image or scatter in the apparatus, and particles with a large charge amount are not developed and are layer regulating blades in the developing tank. And accumulated in members such as rollers and cause image defects such as streaks and blurring due to fusion.

  In the development process design in the image forming apparatus, the development process conditions are set so as to conform to the average value of the toner charge amount. In the apparatus, image defects such as scattering and streaking and blurring are caused, and matching with the apparatus is not good. On the other hand, if the charge amount distribution is sharp as in the present invention, the developability can be controlled by bias adjustment or the like, and a clear image can be given without contaminating the members of the image forming apparatus. is there.

  One of the numerical values indicating the “charge amount distribution” of the toner of the present invention “standard deviation of charge amount” is preferably 1.0 or more and 2.0 or less, more preferably 1.1 or more and 1.8 or less. Especially preferably, it is 1.2 or more and 1.5 or less. When the above upper limit is exceeded, toner adheres to the layer regulation blade and is difficult to be transported, and the adhered toner further blocks the transported toner and contaminates members in the image forming apparatus. There may not be. Moreover, when it falls below the lower limit, it may not be preferable from an industrial viewpoint.

  Furthermore, the value “(Dv50) / (Dn50)” obtained by dividing the volume median diameter (Dv50) by the number median diameter (Dn50) is preferably 1.0 to 1.25, more preferably 1.0 to 1. .20, more preferably 1.0 to 1.15, and is preferably closer to 1.0. Since the electrostatic charge image developing toner having a sharp particle size distribution tends to have uniform chargeability between the solid particles, the electrostatic charge image developing toner Dv / Dn for achieving high image quality and high speed. Is preferably in the above range.

<Toner>
[Types of external additives]
The toner base particles are preferably made into a toner by attaching an external additive to the surface thereof in order to control fluidity and developability. External additives include metal oxides and hydroxides such as alumina, silica, titania, zinc oxide, zirconium oxide, cerium oxide, talc and hydrotalcite, titanium such as calcium titanate, strontium titanate and barium titanate. Inorganic fine powders such as acid metal salts, nitrides such as titanium nitride and silicon nitride, carbides such as titanium carbide and silicon carbide; organic fine powders such as acrylic resins and melamine resins, etc. is there.

  Among them, at least one of the external additives is preferably an inorganic fine powder, more preferably silica, titania or alumina, and those subjected to surface treatment with, for example, a silane coupling agent or silicone oil. Particularly preferred is hydrophobic silica, and even more preferred.

  Among them, those having an average primary particle diameter in the range of 1 to 500 nm are preferable, and more preferably in the range of 5 to 100 nm. It is also preferable to use a combination of a small particle size and a large particle size in the particle size range. The total amount of the external additive is preferably in the range of 0.05% by mass to 10% by mass, more preferably in the range of 0.07% by mass to 7% by mass, particularly preferably based on the toner base particles. It is in the range of 1% by mass to 5% by mass. In the present invention, it is essential that the burying constant described later is 3.0 or less. However, the burying constant is a value that should decrease as the amount of the external additive decreases. Therefore, in the present invention, it is preferable that the external additive is added so that the burying constant described later becomes 3.0 or less even when the amount of the external additive is 1% by mass or more. This is particularly suitable because it is easy to achieve the above effect.

  As the external additive, inorganic fine powder is preferable, and silicon oxide (silica) is more preferable. Silica is more preferably hydrophilized than silane coupling agent or polydimethylsiloxane coupling agent. As the silane coupling agent, hexamethyldisilazane (HMDS) or dimethyldichlorosilane is preferable.

The volume average particle diameter of silica is preferably 8 nm to 70 nm, particularly preferably 10 nm to 20 nm. The BET specific surface area is ^preferably a 30m ² / g~300m 2 / ^g, that of 100m ² / g~250m 2 / g is particularly preferred. Silica is not limited to one type and may be used in combination.

  Even when the external additive is silica or hydrophobic silica, the preferable blending range described above is applied to the toner base particles. 1 mass% or more is particularly preferable.

  The amount of the external additive added depends on the particle size and specific surface area of the external additive, but in the present invention where the particle size of the toner base particles is small, it is essential to add 1% by mass or more. As a measure of the amount added, a state in which the toner surface is mostly covered with an external additive is preferable, and a state in which the entire surface is further covered is more preferable. That is, the surface area of the added external additive is preferably at least twice the spherical assumed specific surface area of the toner base particles. The measuring method and definition of “spherical assumed specific surface area” are based on the measuring method and definition described in the examples.

For example, if the volume median diameter (Dv50) is although spherical assume specific surface area of the toner base particles of 6μm is 0.909m ² / g, it, addition of silica having a BET specific surface area of 200 meters ² / g, the toner mother particles 1g hand, the addition of silica 0.01 g, the surface area of the silica is greater than twice the surface area 0.909M ² of 2m ^2, and the toner base particles.

[External condition]
It is also important to observe the surface state of the toner with an electron microscope or the like without relying on the physical property values for the covered state. Whether or not a sufficient amount of the external additive has been added can be determined by electron microscope observation.

  When the adhesion state of the external additive to the toner was examined, if the adhesion was weak, the external additive detached from the toner due to the stick-and-slip phenomenon was not cleaned, and gradually leaked from the cleaning blade and adhered to the drum. Or accumulated on the charging roller.

  Since the toner particle size is small, the stick-and-slip phenomenon tends to become unstable. Moreover, since the amount of the external additive must be increased in accordance with the surface area, leakage from the cleaning blade is likely to occur. For this reason, when the toner particle size is small and the amount of the external additive is large, it has been found that it is important to uniformly adhere and to control the uniform and stable embedding of the external additive on the surface of the toner base particles.

However, it is difficult to judge the buried state of the external additive only by observation with an electron microscope. “BET specific surface area of externally added toner (m ² / g)” is used as an index of the degree of burying, “spherical assumed specific surface area calculated from volume median diameter (Dv50) of toner” (m ² / g) It was found that by adopting the concept of a value divided by (hereinafter abbreviated as “embedding constant”) and setting the value within a specific range, a toner that exhibits the above effects can be obtained. Here, the measurement method and definition of “BET specific surface area of toner” and “spherical assumed specific surface area” are based on the method and definition described in the examples.

  The toner base particles are not truly spherical, and the BET specific surface area of the toner base particles is naturally larger than the assumed spherical specific surface area. Even in the emulsion-polymerized and agglomerated toner, which is said to be relatively close to a sphere, it is often 1.2 times or more according to the results of the inventors.

  If an external additive that covers the toner surface is added and mixed for a short period of time, the burying constant may be 3.5 to 4 or more. In such a state, the external additive is detached from the toner surface, leaks little by little from the cleaning blade, adheres to the charging roller, etc., and an image defect eventually occurs. In particular, in the case of a toner having a small particle diameter, it is important that the external additive is appropriately buried in consideration of the fine vibration of the cleaning blade, and that the particle size distribution of the toner itself is sharp.

  That is, in a toner having a volume median diameter (Dv50) of 4.0 μm or more and 7.0 μm or less, the burying constant is set to 3.0 or less to prevent detachment of the external additive from the toner and to prevent the external additive from slipping through. To prevent. Further, by sharpening the toner particle size distribution so as to satisfy the above formula (1), the fine vibration of the cleaning blade can be stabilized, and the toner and the detached external additive can be prevented from slipping through. Is also suppressed. In the present invention, the burying constant is essential to be 3.0 (2 significant digits) or less, preferably 2.9 (2 significant digits) or less, more preferably 2.8 (2 significant digits) or less. Particularly preferably, it is 2.6 (2 significant digits) or less. The above numerical range is obtained by rounding off the second decimal place.

  On the other hand, the lower limit of the burying constant is not particularly limited, but is preferably 1.1 (2 significant digits) or more, more preferably 1.3 (2 significant digits) or more, and particularly preferably 1.5 (2 significant digits). Digit) or more. If the burying constant is within the above range, a toner having excellent fluidity can be provided.

  In the present invention, a method for dispersing and attaching the external additive to the toner base particles for realizing the above-described embedment constant will be described in more detail. For the external addition, mixers such as the well-known Henschel mixer, the successor FM mixer manufactured by Mitsui Mining Co., Ltd., and the super mixer manufactured by Kawata are widely used. Alternatively, a high-speed type Q mixer manufactured by Mitsui Mining Co., Ltd., a high-share Hosokawa Micron Nobilta, a Nara Machinery Co., Ltd. hybridizer, or the like may be used.

  By stirring in the mixer, the external additive and the toner base particles are mixed in a nearly uniform state, and the external additive adheres lightly to the toner base particles. Further, the external additive is gradually buried in the surface of the toner base particles due to the collision between the toner base particles with the light additive adhering to the surface or between the toner base particles and the stirring blade. However, if the impact force is weak, burial will not proceed. A strong impact force is required. Due to the strong impact force, the temperature of the collision part rises, and the surface of the toner base particles softens slightly, so that the embedding proceeds.

  It has also been measured that the temperature of the mixture of toner base particles and external additive rises due to impact force. However, since the toner base particles exceed the glass transition point, fusion occurs between the toners, so care must be taken not to raise the temperature too much. In the static state, it is known that the fusion occurs gradually even below the glass transition point, while in the case of stirring in the mixer, the fusion is slightly over the glass transition point, for a short time. Since no adhesion occurs, the temperature rise to the vicinity of the glass transition point is acceptable. However, in that case, after mixing, it is necessary not to leave it statically at that temperature but to cool it quickly.

  The collision energy due to agitation varies greatly depending on the amount charged as well as the shape and rotation speed of the mixer. If the charging amount is small, the collision frequency is low, or the temperature rise is small, and the external additive is not buried much.

  Moreover, not only the heat generated by the collision energy but also the wall surface temperature of the mixer can be positively controlled to control the degree of burial and the burial constant. FM mixers, etc. have a structure that allows warm water and refrigerant to flow through the jacket (wall surface). The mixing is performed while flowing the temperature-controlled warm water, so that the degree of burial of the external additive is 3 It can be stably controlled so as to be less than 0.0.

  There is a method in which the temperature of the refrigerant flowing through the jacket is lowered (0 ° C. to 40 ° C.) to stir and bury it for as long as possible while taking away the heat generated by the collision. 70.degree. C.), there is also a method in which the temperature rise of the toner is accelerated and the embedding progresses quickly. In any case, controlling the jacket temperature has the effect of suppressing the influence (seasonal difference) on the degree of burial due to the temperature of the toner at the start of mixing.

  In the present invention, there was an effect by a method of flowing warm water to assist the increase in the temperature of the toner and speed up the embedding. Further, it is possible to add externally while maintaining the temperature of the inner wall surface of the external device used for external addition in the range of (toner glass transition temperature −15 ° C.) to (glass transition temperature of toner). It is particularly preferable in that it can be stably controlled to 3.0 or less.

  A method of making the mixing time constant in order to keep the degree of embedding constant is common, but there is also a method of terminating the mixing when the temperature of the toner reaches a predetermined temperature because of the influence of temperature. There is also a method in which mixing is terminated when either a predetermined time or a predetermined temperature is satisfied.

  In addition to the method using the collision energy described above, Nippon Pneumatic Industrial Co., Ltd. Meteole Inbo is also known as an external addition method, which is different from the present invention. Meteor embo is a device that melts the surface of the toner by passing it through a temperature range far higher than the glass transition point and changes the shape of the toner, or dissolves external additives attached to the surface into the toner. is there. In meteoreinvo, the surface properties of the toner particles themselves change, and many of the external additive particles are completely integrated with the toner particles and taken into the interior.

  In the present invention, when attention is paid to each of the external additive particles, the particles are appropriately buried, and are intended to realize a state where the head is moderately protruded, and are completely taken into the toner like meteorebow. This is different from the case where many external additive particles are present.

<Developer>
The electrostatic image developing toner of the present invention is for a two-component developer in which a magnetic carrier for conveying the toner to the electrostatic latent image portion coexists, and for a magnetic one-component developer in which magnetic powder is contained in the toner. Alternatively, it may be used for any non-magnetic one-component developer that does not use a magnetic carrier or magnetic powder as a developer. However, in order to achieve the effects of the present invention remarkably, a non-magnetic one-component developer is particularly preferred. It is preferable to use it as a toner for use.

  When used as the above two-component developer, the magnetic carrier mixed with the toner to form the developer may be a known magnetic substance such as iron powder, ferrite, or magnetite, or a resin coating on the surface thereof. What was given can be used. Examples of carrier coating resins that can be used include, but are not limited to, styrene resins, acrylic resins, styrene acrylic copolymer resins, silicone resins, modified silicone resins, and fluorine resins. The average particle size of the carrier is not particularly limited, but preferably has an average particle size of 10 to 200 μm. These carriers are preferably used in an amount of 5 to 100 parts by mass with respect to 1 part by mass of the toner.

<Image forming method>
The image forming method of the present invention will be described with reference to FIG. In the image forming method of the present invention, an electrostatic latent image is formed on the electrostatic charge image holding member 1, toner particles having electrostatic charge are attached and developed on the electrostatic latent image pattern, and then in the transfer step, the electrostatic charge image is formed. Toner is transferred from the holding member 1 onto a transfer material such as paper or an intermediate transfer member. The untransferred toner remaining on the electrostatic charge image holding member 1 is then scraped and collected by the cleaning blade 8 in contact with it in a cleaning process. The electrostatic charge image holding member from which the transfer residual toner has been removed returns to the electrostatic latent image forming step.

[Charging process]
The formation of the electrostatic latent image will be described. First, in the charging step for charging the electrostatic charge image holding member 1, when an electrophotographic photosensitive member is used as the electrostatic charge image holding member 1, the surface of the photosensitive member is uniformly charged by discharge from a charging roller, charging brush, corona wire, or the like. Is granted. The amount of charge is generally in the range of about 300 V to 1 KV in terms of the absolute value of the surface potential of the photoreceptor. In the charging step, it is preferable to use a contact charging member such as a charging roller or a charging brush. The reason for this is that, compared to non-contact charging methods such as corona charging, the contact method is charged by the potential balance of the micro area based on Paschen's law, so it is less affected by afterimages and transfer potentials. This is because it is suitable for forming a high image quality with a diameter toner.

  Next, the electrostatic surface image pattern is formed by releasing the charge on the surface of the photoreceptor by exposure to reflected light from the original or laser light. As the electrostatic charge image holding member 1, an electrostatic latent image pattern may be formed by a technique other than charging and exposure to a photosensitive member.

[Development process]
In the development process, the above-described two-component development method, non-magnetic one-component development method, magnetic one-component method and the like are generally used. The toner 6 charged by frictional charging or the like is brought into contact with or brought close to the electrostatic charge image holding member 1 to transfer the toner 6 to the electrostatic latent image pattern.

  Hereinafter, a general case of the non-magnetic one-component development method will be described. From the toner storage chamber 7, the toner 6 is supplied to the developing roller 2. As a supply method, the toner 6 is naturally attached by its own weight, the toner 6 is moved to the vicinity of the developing roller 2 by agitating the agitator 5 and the like, and the adhesion is promoted by a toner roller. In addition, there is a method of sliding and transferring to the developing roller 2, or a combination thereof. The toner 6 adhering to the developing roller 2 is adjusted to uniform adhesion by a toner layer thickness regulating member 3 such as a doctor blade, an elastic blade, or a trimmer roller.

  The toner 6 is charged by frictional charging by friction between the toner 6 and the developing roller 2, the doctor blade 3, the sponge roller 4, and the like, and between the developing roller 2 and the doctor blade 3, and between the developing roller 2 and the sponge roller 4. There is a method of applying a voltage to the toner 6 to promote charging of the toner 6.

  As the developing roller 2, a general conductive rubber roller, a metal cylinder, or the like is used. The surface of the developing roller 2 may be the same as the material, but may be subjected to chemical surface treatment such as coating with a resin or the like, blasting treatment, oxidation, etc. to perform stable charge control. The same applies to the material of the doctor blade 3, and there may be a case where a resin-based elastic member such as urethane rubber is used, or a case where a leaf spring member such as a stainless steel plate or a square bar member is pressed. Further, like the developing roller 2, surface treatment may be performed.

  The developing roller 2 with the toner uniformly attached is brought into contact with or in proximity to the electrostatic charge image holding member 1 to transfer the toner from the developing roller 2 to the electrostatic charge image holding member 1 to develop the electrostatic latent image pattern. A development bias voltage is generally applied between the electrostatic charge image holding member 1 and the developing roller 2 in order to promote transfer and to prevent toner adhesion to a portion that should be white. The development bias potential is generally set to an intermediate potential between the white background portion and the print portion of the latent image pattern. However, an alternating voltage is also applied to promote development, and the development roller 2 and the electrostatic charge image holding member 1 There is also a jumping method in which the toner is reciprocated between the two and finally the development is faithful to the electrostatic latent image pattern.

[Transfer process]
The electrostatic charge image holding member 1 to which toner is adhered and held in the development process transfers most of the toner to a transfer material (not shown) such as paper or an intermediate transfer body in the transfer process. The transfer material comes into contact with the electrostatic charge image holding member 1, and the toner is transferred by applying voltage or charge from the back surface. As a method of applying a voltage from the back surface, there are a method of applying a voltage to a conductive transfer roller or the like, a method of installing a corona wire or the like on the back surface, and transferring toner with a discharge charge.

[Cleaning process]
[[Cleaning blade]]
Untransferred toner that has not been transferred to the transfer material is scraped and collected by the cleaning blade 8 in the cleaning process. The cleaning blade 8 is preferably made of a material having a rubber hardness of 50 to 90. More preferably, it is 60-80. When it is within this range, the following effects are easily exhibited and the effects of the present invention are easily achieved. Here, the rubber hardness measurement method is based on JIS k6301 (spring type A type), and the above-mentioned “rubber hardness” is defined as that measured.

  The material of the cleaning blade 8 is not particularly limited, but urethane rubber, silicone rubber and the like are preferable. One end of the cleaning blade 8 is fixed, and the ridge line of the other free end is pressed against the electrostatic charge image holding member 1. The transfer residual toner accumulates in this contact portion. When a large amount of transfer residual toner accumulates, the toner is moved and stored from the cleaning blade 8 to the recovery chamber. In order to move to the collection chamber, the toner previously scraped off is pushed out by the toner that is sequentially scraped and moves toward the fixed end of the cleaning blade 8. There are many cases. Further, the collected transfer residual toner may be returned to the toner storage chamber 7 in the development process and reused. The electrostatic charge image holding member from which the toner has been removed from the surface returns to the process of forming the electrostatic latent image. When a photoreceptor is used as the electrostatic charge image holding member, the previous electrostatic latent image pattern may be erased by static elimination light before the charge is uniformly applied.

[[Stick and slip phenomenon]]
In the cleaning process, the cleaning blade 8 vibrates slightly due to the stick-and-slip phenomenon described above. When a large amount of toner having a particle size of 2.00 μm or more and 3.56 μm or less is included, cleaning failure is likely to occur, and this should be reduced as much as possible.

  Further, when the relationship with the volume median diameter is examined in detail, it is considered that the following phenomenon occurs with the stick-and-slip phenomenon. Along with the minute vibration, the cleaning blade is lifted up in a state where toner is temporarily sandwiched between the contact portion between the electrostatic charge image holding member and the edge of the edge of the cleaning blade. A slight gap is generated between the charge image holding members. The size of the gap is related to the volume median diameter (Dv50) of the toner, and it seems that the larger the volume median diameter (Dv50), the wider the gap and the higher the probability of the gap.

  Therefore, a toner having a relatively large volume median diameter (Dv50) in a volume median diameter (Dv50) in the range of 4.0 μm to 7.0 μm has a ratio of a particle diameter of 2.00 μm to 3.56 μm. Need to be less. On the other hand, in the toner having a relatively small volume median diameter (Dv50) in the volume median diameter (Dv50) in the range of 4.0 μm to 7.0 μm, the ratio of the particle diameter of 2.00 μm to 3.56 μm is In a small amount, a relatively large range is allowed. As shown in Examples and Comparative Examples, the relationship appears as a relational expression such as the expression (1).

  In addition, since the cleaning failure when a coarse material adheres to the cleaning blade continues to occur at the same location, the linear image failure continues to occur at the same location. The cleaning failure that has been made is a cleaning failure that occurs temporarily and not a long linear image failure. For this reason as well, it is considered that such a cleaning defect is caused by a phenomenon of temporary pinching.

  With regard to the cleaning performance of the toner having a volume median diameter (Dv50) larger than 7 μm, which has been widely used in the past, it is not necessary to consider the ratio of the particle diameter of 2.00 μm to 3.56 μm. This is thought to be because the phenomenon in which the toner is temporarily caught due to the vibration speed and vibration width peculiar to the stick-and-slip phenomenon is difficult to occur with toners larger than 7 μm.

  In recent years, a toner having a small volume median diameter (Dv50) has been used, and even a recent polymerized toner or a pulverized toner whose surface has been smoothed by surface treatment or the like is more temporarily used. The phenomenon of being caught is becoming easy to occur. In particular, with polymerized toner, the slipping phenomenon is more likely to occur as the circularity is higher (closer to a sphere). If the circularity exceeds 0.94, a slip-through phenomenon is more likely to occur. In the case of a toner having a small particle size and a high degree of circularity, the above type of cleaning failure can be improved only by using the particle size distribution in the present invention.

  However, it has been found that the particle size distribution alone is not sufficient, and that the control of the adhesion state of the external additive is more important for the cleaning process of the small particle size toner. The presence of an external additive is important in order to stabilize the stick-and-slip microvibration, and the state in which the external additive is buried in the toner base particles is important. In the case of a toner having a small particle diameter with a volume median diameter (Dv50) of 4.0 μm or more and 7.0 μm or less, the present invention has been able to solve the above-mentioned types of poor cleaning only when the embedding constant is set to 3.0 or less. .

  In addition, if the image forming method of the present invention is used, not only the improvement of the above-mentioned type of cleaning failure is seen, but also the conventionally known “cleaning failure when accumulated and adhered to the cleaning blade” is also observed. Can improve.

  After the cleaning process, the electrostatic charge image holding member 1 from which the toner is removed returns to the electrostatic latent image forming process (developing process). When a photosensitive member is used as the electrostatic charge image holding member 1, the previous electrostatic latent image pattern may be erased by static elimination light before the charge is uniformly applied.

<Combination with device>
Since the toner of the present invention has a sharp charge amount distribution, the contamination (toner scattering) in the image forming apparatus caused by poorly charged toner is very small. This effect is remarkably exhibited particularly in a high-speed type image forming apparatus in which the development process speed for the electrostatic latent image carrier is 100 mm / second or more.

  Further, since the toner of the present invention has a sharp charge amount distribution, the developability is very good, and there are very few toner particles that accumulate without being developed. The effect is exhibited in the apparatus. Specifically, a toner used in an image forming apparatus that satisfies the following formula (4) is preferable in order to sufficiently exhibit the above-described effects of the present invention.

(4) Guaranteed lifetime number of sheets (sheets) x printing rate ≧ 400 (sheets) of a developer filled with developer
In the formula (4), “printing rate” is represented by a value obtained by dividing the sum of the printed portion areas by the total area of the printing medium in the printed matter for determining the guaranteed life number as the performance of the image forming apparatus. The “print rate” of the print% of “5%” is “0.05”.

  Furthermore, since the toner of the present invention has a very sharp particle size distribution, the reproducibility of the latent image is very good. Therefore, the effect of the present invention is sufficiently exerted particularly when used in an image forming apparatus having a resolution of 600 dpi or more for the electrostatic latent image carrier.

  The image forming method of the present invention will be described in more detail with reference to the drawings. FIG. 1 is an explanatory view showing an example of a developing device using a non-magnetic one-component toner that can be used for performing an image forming method using the toner of the present invention. In FIG. 1, the toner 6 of the present invention built in the toner hopper 7 is forcibly brought to a roller-like sponge roller (toner supply auxiliary member) 4 by the stirring blade 5, and the toner is supplied to the sponge roller 4. The The toner taken into the sponge roller 4 is carried to the toner conveying member 2 by the sponge roller 4 rotating in the direction of the arrow, and is rubbed and electrostatically or physically adsorbed. It rotates strongly in the direction of the arrow, and a uniform thin toner layer is formed by a steel elastic blade (toner layer thickness regulating member) 3 and is frictionally charged. Thereafter, the toner is conveyed to the surface of the electrostatic latent image carrier 1 that is in contact with the toner conveying member 2, and the latent image is developed. The electrostatic latent image is obtained, for example, by subjecting an organic photoreceptor to DC charging of 500 V and then exposure.

  The toner on the electrostatic charge image holding member is then transferred to a transfer material such as plain paper in a transfer process. In the transfer process, a method is generally used in which a transfer material is brought into contact with an electrostatic charge image holding member to which toner is electrostatically attached, and an electric field in a direction in which the toner is transferred from the back surface of the transfer material to the transfer material side. As a method for forming an electric field, there are a method for charging a transfer material by corona discharge such as corotron from the back surface of the transfer material, a method for forming an electric field by applying a voltage to a conductive roller or the like. In the case of a method using a conductive roller or the like, the charge of the method of adhering the toner to the transfer material is increased by discharging the charge to the transfer material according to Paschen's law at the time of charge injection from the transfer roller to the transfer material or contact and separation. This is more preferable because the toner can be stably held on the transfer material even after the transfer material is separated from the electrostatic charge image holding member. The toner that is not transferred in the transfer process and remains on the electrostatic charge image holding member is then scraped off by the cleaning blade 8 in the cleaning process. The electrostatic image holding member whose surface has been cleaned is re-formed with an electrostatic latent image, and then returns to the developing step where it comes into contact with the toner conveying member 2 again. When using an organic photoreceptor, as a method for re-forming an electrostatic latent image, the latent image is neutralized as necessary, uniformly charged, and an electrostatic latent image is formed by exposure.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist. In the following examples, “part” means “part by mass”.

<Measurement method and definition of volume average diameter (Mv)>
The volume average diameter (Mv) of particles having a volume average diameter (Mv) of less than 1 μm is handled by using Nitraso Co., Ltd., model: Microtrac Nanotrac 150 (hereinafter abbreviated as “Nanotrack”). In accordance with the instructions, using the company's analysis software Microtrac Particle Analyzer Ver10.1.2.-019EE, using ion-exchanged water with an electric conductivity of 0.5 μS / cm as the dispersion medium, enter the following conditions or the following conditions respectively: And measured by the method described in the instruction manual.

For wax dispersion and polymer primary particle dispersion,
Solvent refractive index: 1.333
-Measurement time: 100 seconds-Number of measurements: 1 time-Particle refractive index: 1.59
-Permeability: Transmission-Shape: True spherical shape-Density: 1.04

For pigment premix liquid and colorant dispersion,
Solvent refractive index: 1.333
-Measurement time: 100 seconds-Number of measurements: 1 time-Particle refractive index: 1.59
・ Transparency: Absorption ・ Shape: Non-spherical shape ・ Density: 1.00

<Measurement method and definition of volume median diameter (Dv50), number median diameter (Dn50)>
As a pre-measurement treatment of the toner finally obtained through the external addition process, it was performed as follows. In a cylindrical polyethylene (PE) beaker having an inner diameter of 47 mm and a height of 51 mm, 0.100 g of toner using a spatula, 20% by weight DBS aqueous solution using a dropper (Daiichi Kogyo Seiyaku Co., Ltd., Neogen S-20A) 0.15 g was added. At this time, toner and a 20% DBS aqueous solution were added only to the bottom of the beaker so that the toner would not scatter on the edge of the beaker. Next, the mixture was stirred for 3 minutes using a spatula until the toner and 20% DBS aqueous solution became a paste. At this time, the toner was prevented from being scattered on the edge of the beaker.

  Subsequently, 30 g of dispersion medium Isoton II was added, and the mixture was stirred for 2 minutes using a spatula to obtain a uniform solution as a whole. Next, a fluororesin-coated rotor having a length of 31 mm and a diameter of 6 mm was placed in a beaker and dispersed using a stirrer at 400 rpm for 20 minutes. At this time, using a spatula at a rate of once every 3 minutes, macroscopic particles visually observed at the gas-liquid interface and the edge of the beaker were dropped into the beaker so as to form a uniform dispersion. Subsequently, this was filtered through a mesh having an opening of 63 μm, and the obtained filtrate was designated as “toner dispersion”.

  Regarding the measurement of the particle diameter during the production process of the toner base particles, the filtrate obtained by filtering the agglomerated slurry with a 63 μm mesh was used as the “slurry liquid”.

  The volume median diameter (Dv50) of the particles is Bocman Coulter's Multisizer III (aperture diameter 100 μm) (hereinafter abbreviated as “Multisizer”), the dispersion medium is Isoton II, and the above-mentioned “ The “toner dispersion liquid” or “slurry liquid” was diluted to a dispersoid concentration of 0.03% by mass and measured with Multisizer III analysis software with a KD value of 118.5. The measurement particle diameter range is from 2.00 to 64.00 μm, and this range is discretized into 256 divisions so as to be equidistant on a logarithmic scale, and the volume calculated based on the statistical values on the basis of the volume is the volume. The median diameter (Dv50) was used.

<Measurement Method and Definition of Number% (Dns) of Toner with Particle Size of 2.00 μm to 3.56 μm>
As a pre-measurement process for the toner after the external addition step, the following procedure was performed. In a cylindrical polyethylene (PE) beaker having an inner diameter of 47 mm and a height of 51 mm, 0.100 g of toner using a spatula, 20% by weight DBS aqueous solution using a dropper (Daiichi Kogyo Seiyaku Co., Ltd., Neogen S-20A) 0.15 g was added. At this time, toner and a 20% DBS aqueous solution were added only to the bottom of the beaker so that the toner would not scatter on the edge of the beaker. Next, the mixture was stirred for 3 minutes using a spatula until the toner and 20% DBS aqueous solution became a paste. At this time, the toner was prevented from being scattered on the edge of the beaker.

  Subsequently, 30 g of dispersion medium Isoton II was added, and the mixture was stirred for 2 minutes using a spatula, and the whole was made into a uniform solution visually. Next, a fluororesin-coated rotor having a length of 31 mm and a diameter of 6 mm was placed in a beaker and dispersed using a stirrer at 400 rpm for 20 minutes. At this time, macroscopic particles visually observed at the gas-liquid interface and the edge of the beaker were dropped into the beaker at a rate of once every 3 minutes so as to form a uniform dispersion. Subsequently, this was filtered with a mesh having an opening of 63 μm, and the obtained filtrate was used as a toner dispersion.

  For the number% (Dns) of toner having a particle size of 2.00 μm or more and 3.56 μm or less, a multisizer (aperture diameter 100 μm) is used, and Isoton II manufactured by the same company is used as a dispersion medium. The “slurry liquid” was diluted to a dispersoid concentration of 0.03% by mass and measured with Multisizer III analysis software with a KD value of 118.5.

  The lower limit particle size of 2.00 μm is the detection limit of the measuring device multisizer, and the upper limit particle size of 3.56 μm is a prescribed channel value in the measuring device multisizer. In the present invention, an area having a particle size of 2.00 μm or more and 3.56 μm or less is recognized as a fine powder area.

  The measurement particle size range is from 2.00 to 64.00 μm, and this range is discretized into 256 divisions so as to be equidistant on a logarithmic scale, and based on the statistical value on the basis of the number, 2.00 To 3.56 μm, the ratio of the particle size component was calculated on the basis of the number and was defined as “Dns”.

<Definition and calculation of spherical specific surface area>
Assuming that the spherical spherical specific surface area of the toner is the volume median diameter Dv50 (μm) measured by Multisizer III and the true specific gravity ρ (g / cm ³ ) of the toner,
Since the volume V of a sphere of diameter Dv50 is, V = [pi × ^(Dv50) is 3/6,
Its mass becomes M = ρ × π × (Dv50 ) 3/6.
On the other hand, the surface area S of a sphere having a diameter of Dv50 is S = π × (Dv50) ² .
Therefore, the spherical assumed specific surface area S / M is
S / M = 6 / (ρ × Dv50).
Furthermore, considering the volume median diameter Dv50 (μm), the true specific gravity ρ (g / cm ³ ) of the toner, and the unit,
[Spherical assumed specific surface area] (m ² / g)
= 6 / [ρ (g / cm ³ ) × Dv50 (μm)].

For example, when the toner has a true specific gravity of 1.1 (g / cm ³ ) and a volume median diameter (Dv50) of 6 μm as a main component, a toner composed mainly of a copolymer containing styrene and butyl acrylate as main monomers is spherical. The assumed specific surface area is 0.909 (m ² / g).

The toner used in this example has a true specific gravity of 1.1 (g / cm ³ ) based on a copolymer mainly composed of styrene and butyl acrylate. Calculated.

<Measurement method and definition of BET specific surface area>
The BET specific surface area was measured using a fully automatic BET specific surface area measuring device Macsorb HM model-1200 series model-1208 manufactured by Mountec Co., Ltd. The toner sample was loaded in the cell at 0.5 ± 0.1 g. The deaeration temperature was 40 ° C. and the deaeration time was 20 minutes. The result is obtained in terms of surface area per unit mass (unit: m ² / g).

  The BET specific surface area of the toner base particles is the result of measuring the toner base particles before external addition alone. The BET specific surface area of the toner is a result of measurement with a toner obtained by externally adding an external additive to toner base particles and removing coarse particles with a sieve.

<Definition of burial constant>
The “embedding constant” is the “spherical assumed specific surface area (m) calculated from the“ volume median diameter (Dv50) of the toner ”obtained from the“ BET specific surface area (m ² / g) of the toner ”obtained by the above measurement method. ² / g) ". "Buried constant" is, because it is divided by ^(m 2 / g) to ^(m 2 / g), the unit is not.

<Measuring method and definition of average circularity>
The “average circularity” in the present invention is measured as follows and is defined as follows. That is, the toner base particles are dispersed in a dispersion medium (Isoton II, manufactured by Beckman Coulter, Inc.) so as to be in the range of 5720-7140 particles / μL, and a flow type particle image analyzer (Sysmex Corporation (formerly Toa Medical Electronics)). (Manufactured by FPIA 2100), measurement is performed under the following apparatus conditions, and the value is defined as “average circularity”. In the present invention, the same measurement is performed three times, and an arithmetic average value of three “average circularity” is adopted as the “average circularity”.
・ Mode: HPF
-HPF analysis amount: 0.35 μL
-HPF detection number: 2000-2500

The following is measured by the above device and automatically calculated and displayed in the above device, and “circularity” is defined by the following formula.
[Circularity] = [Perimeter of a circle with the same area as the projected particle area] / [Perimeter of projected particle image]
And 2000-2500 which is the number of HPF detection is measured, and the arithmetic average (arithmetic mean) of the circularity of each individual particle is displayed on the apparatus as “average circularity”.

<Measurement method and definition of electrical conductivity>
The electrical conductivity was measured using a conductivity meter (a personal SC meter model SC72 and a detector SC72SN-11 manufactured by Yokogawa Electric Corporation) according to an ordinary method according to the instruction manual.

<Measuring method and definition of melting point peak temperature, melting peak half width, crystallization temperature, crystallization peak half width>
From the endothermic curve when the temperature is raised from 10 ° C. to 110 ° C. at a rate of 10 ° C./min using the method described in the company's instruction manual using Seiko Instruments Inc. model: SSC5200, the melting point peak temperature The half-width of the melting peak was measured, and then the crystallization temperature and the half-width of the crystallization peak were measured from the exothermic curve when the temperature was lowered from 110 ° C. to 10 ° C. at a rate of 10 ° C./min.

<Measurement method and definition of solid content concentration>
Using a solid content concentration measuring instrument INFRARED MOISTURE DETERMINATION BALANCE model FD-100, manufactured by Kett Science Laboratory, weighed 1.00 g of a sample containing solid content on a balance, and the conditions of a heater temperature of 300 ° C. and a heating time of 90 minutes The solid content concentration was measured.

<Method of live-action evaluation>
As an apparatus for evaluating the actual image, an A4 size laser printer (A4 size paper longitudinal feed 21 sheets / minute, guaranteed life of 8000 sheets at a printing rate of 5%) was used. The system is a non-magnetic single component rubber development roller contact development system, using an organic photoreceptor as a latent image holding member, uniformly charging the photoreceptor with a charging roller as a contact charging member, and electrostatic latent by laser light. An image is formed and transferred from a photosensitive member to a transfer material such as paper held on a semiconductive belt, and residual toner on the photosensitive member is cleaned with a urethane rubber cleaning blade having a rubber hardness of 70. The resolution to the latent image carrier was 600 dpi. When the speed at which the paper came out of the printer was measured with a stopwatch, the process speed was 120 to 130 mm / sec. 230 g of toner was filled in the process cartridge for this printer, and the actual image was evaluated.

  In the actual image evaluation, an image quality evaluation pattern was printed every 1000 sheets after printing 500 sheets, after printing 1000 sheets, and thereafter 1000 sheets. The running was continued until the toner in the cartridge ran out or a total of 8000 sheets was reached. A pattern with a printing rate of 5% was printed between the image quality evaluation patterns. As necessary, the toner scattering around the developing roller and the contamination of the charging roller were observed and confirmed by disassembling the cartridge.

Example 1
<Preparation of wax / long-chain polymerizable monomer dispersion A1>
Paraffin wax (Nihon Seiki Co., Ltd. HNP-9, surface tension 23.5 mN / m, thermal characteristics: melting point peak temperature 82 ° C., melting heat 220 J / g, melting peak half width 8.2 ° C., crystallization temperature 66 ° C., Crystallization peak half-value width 13.0 ° C.) 27 parts (540 g), stearyl acrylate (manufactured by Tokyo Chemical Industry Co., Ltd.) 2.8 parts, 20 mass% sodium dodecylbenzenesulfonate aqueous solution (Daiichi Kogyo Seiyaku Co., Ltd., Neogen S20A) ( (Hereinafter abbreviated as “20% DBS aqueous solution”) 1.9 parts and 68.3 parts of demineralized water are heated to 90 ° C. and stirred for 10 minutes using a homomixer (Mark II f model manufactured by Tokushu Kika Kogyo Co., Ltd.). did.

  Next, this dispersion was heated to 90 ° C., and circulation emulsification was started under a pressure condition of 25 MPa using a homogenizer (manufactured by Gorin, 15-M-8PA type). Dispersion was carried out until (Mv) reached 250 nm to prepare a wax / long-chain polymerizable monomer dispersion A1 (emulsion solid content concentration = 30.2 mass%).

<Preparation of polymer primary particle dispersion A1>
In a reactor (inner volume 21 L, inner diameter 250 mm, height 420 mm) equipped with a stirrer (three blades), a heating / cooling device, a concentrating device, and a raw material / auxiliary charging device, the wax / long-chain polymerizable unit is added. The monomer dispersion A1 (35.6 parts, 712.12 g) and 259 parts of demineralized water were charged, and the temperature was raised to 90 ° C. under a nitrogen stream while stirring.

  Thereafter, the mixture of the following “polymerizable monomers and the like” and “emulsifier aqueous solution” was added to the solution over 5 hours while continuing to stir the liquid. The time at which this mixture was started to be dropped was designated as “polymerization start”, and the following “initiator aqueous solution” was added over 4.5 hours from 30 minutes after the start of polymerization. Further, after 5 hours from the start of polymerization, the following “additional start” The agent aqueous solution ”was added over 2 hours, and the internal temperature was maintained at 90 ° C. for 1 hour while continuing stirring.

[Polymerizable monomers, etc.]
Styrene 76.8 parts (1535.0 g)
23.2 parts butyl acrylate
Acrylic acid 1.5 parts
Hexanediol diacrylate 0.7 parts
1.0 part of trichlorobromomethane

[Emulsifier aqueous solution]
20% DBS aqueous solution 1.0 part
67.1 parts of demineralized water

[Initiator aqueous solution]
15.5 parts of 8% by weight aqueous hydrogen peroxide solution
15.5 parts of 8 mass% L (+)-ascorbic acid aqueous solution

[Additional initiator aqueous solution]
8 mass% L (+)-ascorbic acid aqueous solution 14.2 parts

  After the completion of the polymerization reaction, the mixture was cooled to obtain a milky white polymer primary particle dispersion A1. The volume average diameter (Mv) measured using Nanotrac was 280 nm, and the solid content concentration was 21.1% by mass.

<Preparation of polymer primary particle dispersion A2>
In a reactor (inner volume 21 L, inner diameter 250 mm, height 420 mm) equipped with a stirrer (three blades), a heating / cooling device, a concentrating device, and each raw material / auxiliary charging device, 1.0 part of a 20 mass% DBS aqueous solution Then, 312 parts of demineralized water was added, the temperature was raised to 90 ° C. under a nitrogen stream, and 3.2 parts of an 8% by mass hydrogen peroxide aqueous solution and 3.2 parts of an 8% by mass L (+)-ascorbic acid aqueous solution were stirred. Added all at once. The time point 5 minutes after the batch addition of these is defined as “polymerization start”.

  A mixture of the following “polymerizable monomers etc.” and “emulsifier aqueous solution” was added over 5 hours from the start of polymerization, and the following “initiator aqueous solution” was added over 6 hours from the start of polymerization. While stirring, the internal temperature was maintained at 90 ° C. for 1 hour.

[Polymerizable monomers, etc.]
92.5 parts of styrene (1850.0 g)
7.5 parts butyl acrylate
Acrylic acid 0.5 part
0.5 parts of trichlorobromomethane

[Emulsifier aqueous solution]
1.5 parts of 20% DBS aqueous solution
66.0 parts of demineralized water

[Initiator aqueous solution]
18.9 parts of 8% hydrogen peroxide solution
8% by mass L (+)-ascorbic acid aqueous solution 18.9 parts

  After completion of the polymerization reaction, the mixture was cooled to obtain a milky white polymer primary particle dispersion A2. The volume average diameter (Mv) measured using Nanotrac was 290 nm, and the solid content concentration was 19.0% by mass.

<Preparation of Colorant Dispersion A>
Carbon black (Mitsubishi Chemical Co., Ltd.) manufactured by a furnace method with a 300 L internal volume equipped with a stirrer (propeller blade) and a toluene extract having an ultraviolet absorbance of 0.02 and a true density of 1.8 g / cm ³ Mitsubishi Carbon Black MA100S) 20 parts (40 kg), 20% DBS aqueous solution 1 part, nonionic surfactant (manufactured by Kao Corp., Emulgen 120) 4 parts, ion-exchanged water 75 parts with an electric conductivity of 2 μS / cm In addition, it was predispersed to obtain a pigment premix solution. The volume average diameter (Mv) of carbon black in the dispersion after pigment premixing measured with Nanotrac was 90 μm.

The pigment premix solution was supplied as a raw material slurry to a wet bead mill and subjected to one-pass dispersion. The inner diameter of the stator was φ75 mm, the separator diameter was φ60 mm, the distance between the separator and the disk was 15 mm, and zirconia beads having a diameter of 100 μm (true density of 6.0 g / cm ³ ) were used as a dispersion medium. Since the effective internal volume of the stator is 0.5 L and the filling volume of the media is 0.35 L, the media filling rate is 70% by mass. The pigment premix liquid is continuously supplied from the supply port at a supply speed of 50 L / hr by a non-pulsating metering pump, and the rotor rotation speed is constant (peripheral speed at the rotor tip is 11 m / sec), and continuously from the discharge port. To obtain a black colorant dispersion A. The volume average diameter (Mv) of the colorant dispersion A measured with Nanotrack was 150 nm, and the solid content concentration was 24.2% by mass.

<Manufacture of toner mother particle A>
Using the following components, toner base particles A were produced by carrying out the following aggregation processes (core material aggregation process, shell coating process), circularization process, washing process, and drying process.
Polymer primary particle dispersion A1 95 parts as solid content (998.2 g as solid content)
Polymer primary particle dispersion A2 5 parts as solid content
Colorant dispersion A 6 parts as colorant solids
20% DBS aqueous solution In the core material agglomeration process, the solid content is 0.2 parts.
20% DBS aqueous solution In the rounding process, 6 parts as solid content

○ Core material aggregation process
Polymer primary particle dispersion A1 and 20% in a mixer (volume 12 L, inner diameter 208 mm, height 355 mm) equipped with a stirring device (double helical blade), heating / cooling device, concentrating device, and each raw material / auxiliary charging device A DBS aqueous solution was charged and mixed uniformly at an internal temperature of 7 ° C. for 5 minutes. Subsequently, with stirring at 250 ° C. at an internal temperature of 7 ° C., 0.52 parts of FeSO ₄ .7H ₂ O as a 5% by mass aqueous solution of ferrous sulfate was added over 5 minutes, and then colorant dispersion A Was added uniformly over 5 minutes, and the mixture was uniformly mixed at an internal temperature of 7 ° C., and a 0.5% by mass aqueous solution of aluminum sulfate was added dropwise over 8 minutes under the same conditions (solid content relative to resin solid content). 0.10 parts). Thereafter, the internal temperature was raised to 54.0 ° C. while maintaining the rotational speed of 250 rpm, the volume median diameter (Dv50) was measured using a multisizer, and grown to 5.32 μm.

○ Shell coating process
Thereafter, with the internal temperature of 54.0 ° C. and the rotation speed of 250 rpm, the polymer primary particle dispersion A2 was added over 3 minutes and held as it was for 60 minutes.

○ Circularization process
Subsequently, the rotational speed was reduced to 150 rpm (a peripheral speed of 1.56 m / second at the tip of the stirring blade, a stirring speed reduced by 40% with respect to the rotational speed of the aggregation process), and then a 20% DBS aqueous solution (6 parts as solid content). Was added over 10 minutes, and then the temperature was raised to 81 ° C. over 30 minutes, and heating and stirring were continued under these conditions until the average circularity reached 0.943. Thereafter, the mixture was cooled to 30 ° C. over 20 minutes to obtain a slurry.

○ Cleaning process
The obtained slurry was extracted and subjected to suction filtration with an aspirator using filter paper of type 5 C (No5C manufactured by Toyo Roshi Kaisha, Ltd.). The cake remaining on the filter paper is transferred to a stainless steel container having an internal volume of 10 L equipped with a stirrer (propeller blade), and 8 kg of ion exchange water having an electric conductivity of 1 μS / cm is added and stirred uniformly at 50 rpm. Thereafter, stirring was continued for 30 minutes.

  Thereafter, the filter paper was suction filtered with an aspirator again using Type 5 C (Toyo Filter Paper No. 5C) filter paper, and the solid matter remaining on the filter paper was again equipped with a stirrer (propeller blade) and had an electrical conductivity of 1 μS / cm. It was transferred to a container with an internal volume of 10 L containing 8 kg of ion-exchanged water, and uniformly dispersed by stirring at 50 rpm and kept stirring for 30 minutes. When this process was repeated 5 times, the electrical conductivity of the filtrate was 2 μS / cm.

○ Drying process
The solid matter obtained here was spread on a stainless steel bat so as to have a height of 20 mm, and dried in a blow dryer set at 40 ° C. for 48 hours to obtain toner mother particles A.

<Manufacture of toner>
External Addition Step To mix toner base particle A and external additive, Mitsui FM mixer FM20C / I (machine number FM201005) manufactured by Mitsui Mining Co., Ltd., upper blade Y0 type and lower blade A0 type were used. The mixing was performed while flowing warm water adjusted to 50 ° C. through the jacket. In addition, it was considered that the temperature of the jacket was warmed by flowing warm water at least 20 minutes before the mixing operation. As a result, the temperature of the inner wall surface of the external device was kept in the range of (the glass transition temperature of the toner—15 ° C.) to (the glass transition temperature of the toner).

To 100 parts by weight (1500 g) of the toner base particle A obtained above, 1.75 parts by weight (26.25 g) of H30TD silica manufactured by Clariant Co., Ltd. was added as an external additive, mixed for 15 minutes at 3000 rpm, and further Maruo calcium. 0.28 parts by weight (4.20 g) of HAP-05NP calcium phosphate fine powder manufactured by the company was added and mixed at 3000 rpm for 5 minutes. The mixture was passed through a 200-mesh sieve to remove coarse particles to obtain a toner. Incidentally, BET specific surface area measured by the external additive alone, H30TD silica 144.4m ² / g, the HAP-05NP calcium phosphate fine powder was 26.47m ² / g.

  The measured values for the toner obtained here are summarized in Table 1.

  The above-mentioned toner was evaluated for actual shooting as described above. There was no particular problem up to 8000 sheets, and the image quality was good. There was no toner scattering, and a small amount of toner and white external additive adhered to the charging roller, but no image defects or other problems were found.

Comparative Example 1
Using the toner base particles A used in Example 1, the following tests were performed.
<Manufacture of toner>
External Addition Step To mix toner base particle A and external additive, Mitsui Henschel Mixer FM10B / I (machine number FM10745) manufactured by Mitsui Mining Co., Ltd., upper blade Z type and lower blade A0 type were used. The mixing was performed while flowing warm water adjusted to 50 ° C. through the jacket. In addition, it was considered that the temperature of the jacket was warmed by flowing warm water at least 20 minutes before the mixing operation.

To 100 parts by weight (500 g) of toner base particle A, 1.75 parts by weight (8.75 g) of H30TD silica manufactured by Clariant Co. as an external additive is added and mixed for 30 minutes at 3000 rpm, and further, HAP-05NP manufactured by Maruo Calcium Co., Ltd. is used. An additional 0.28 parts by weight (1.40 g) of calcium phosphate fine powder was added and mixed at 3000 rpm for 10 minutes. The mixture was passed through a 200-mesh sieve to remove coarse particles to obtain a toner. The mixing ratio of the toner base particles and the external additive is the same as that in Example 1. Incidentally, BET specific surface area measured by the external additive alone, H30TD silica 144.4m ² / g, the HAP-05NP calcium phosphate fine powder was 26.47m ² / g.

  The measured values for the toner obtained here are summarized in Table 1.

  The above-mentioned toner was evaluated for actual shooting as described above. Dirt was seen on the white background from around 3000 sheets. The stain coincided with the charging roller cycle. Since it deteriorated further, it ended with 5000 sheets. As compared with Example 1, the charging roller had more white external additive attached thereto. A large amount of the external additive adhered to the charging roller, resulting in poor charging and appearing in the image.

Example 2
Using the toner base particles A used in Example 1, the following tests were performed.
<Manufacture of toner>
External addition process Instead of 1.75 parts by weight (26.25 g) of H30TD silica manufactured by Clariant, 1.40 parts by weight (21.00 g) of H30TM silica manufactured by Clariant was used, and the mixing for 15 minutes was extended to 20 minutes. A toner was prepared by mixing and sieving in the same manner as in Example 1 except that the calcium phosphate fine powder was not added, and therefore no additional mixing was performed for 5 minutes. In addition, the BET specific surface area measured with the external additive alone was 182.9 m ² / g for H30TM silica.

  The measured values for the toner obtained here are summarized in Table 1.

  The above-mentioned toner was evaluated for actual shooting as described above. There was no particular problem up to 8000 sheets, and the image quality was good. There was no toner scattering, and a small amount of toner and white external additive adhered to the charging roller, but no image defects or other problems were found.

Comparative Example 2
<Preparation of wax / long-chain polymerizable monomer dispersion B1>
Paraffin wax (HNP-9 manufactured by Nippon Seiki Co., Ltd., surface tension 23.5 mN / m, thermal characteristics: melting point peak temperature 82 ° C., melting peak half width 8.2 ° C., crystallization temperature 66 ° C., crystallization peak half width 13 27 ° C. (540 g), 2.8 parts stearyl acrylate (manufactured by Tokyo Chemical Industry Co., Ltd.), 1.9 parts 20% DBS aqueous solution, 68.3 parts demineralized water to 90 ° C. and heated to a homomixer (special The mixture was stirred for 10 minutes using Mark II f model manufactured by Meika Kogyo Co., Ltd.

  Next, this dispersion was heated to 90 ° C., and circulation emulsification was started under a pressure condition of 25 MPa using a homogenizer (manufactured by Gorin, 15-M-8PA type). Dispersion was carried out until (Mv) reached 250 nm to prepare a wax / long-chain polymerizable monomer dispersion B1 (emulsion solid content concentration = 30.2 mass%).

<Preparation of polymer primary particle dispersion B1>
In a reactor (inner volume 21 L, inner diameter 250 mm, height 420 mm) equipped with a stirrer (three blades), a heating / cooling device, and each raw material / auxiliary charging device, the above wax / long-chain polymerizable monomer dispersion B1 35.6 parts (712.12 g) and 259 parts of demineralized water were charged, and the temperature was raised to 90 ° C. under a nitrogen stream while stirring.

  Thereafter, the mixture of the following “polymerizable monomers and the like” and “emulsifier aqueous solution” was added to the solution over 5 hours while continuing to stir the liquid. The time at which this mixture was started to be dropped was designated as “polymerization start”, and the following “initiator aqueous solution” was added over 4.5 hours from 30 minutes after the start of polymerization. Further, after 5 hours from the start of polymerization, the following “additional start” The agent aqueous solution ”was added over 2 hours, and the internal temperature was maintained at 90 ° C. for 1 hour while continuing stirring.

[Polymerizable monomers, etc.]
Styrene 76.8 parts (1535.0 g)
23.2 parts butyl acrylate
Acrylic acid 1.5 parts
Hexanediol diacrylate 0.7 parts
1.0 part of trichlorobromomethane

[Emulsifier aqueous solution]
20% DBS aqueous solution 1.0 part
67.1 parts of demineralized water

[Initiator aqueous solution]
15.5 parts of 8% by weight aqueous hydrogen peroxide solution
15.5 parts of 8 mass% L (+)-ascorbic acid aqueous solution

[Additional initiator aqueous solution]
8 mass% L (+)-ascorbic acid aqueous solution 14.2 parts

  After completion of the polymerization reaction, the mixture was cooled to obtain a milky white polymer primary particle dispersion B1. The volume average diameter (Mv) measured using Nanotrac was 265 nm, and the solid content concentration was 22.3 mass%.

<Preparation of silicone wax dispersion B2>
Alkyl-modified silicone wax (thermal characteristics: melting point peak temperature 77 ° C., heat of fusion 97 J / g, melting peak half width 10.9 ° C., crystallization temperature 61 ° C., crystallization peak half width 17.0 ° C.) 27 parts (540 g) Then, 1.9 parts of a 20% DBS aqueous solution and 71.1 parts of demineralized water were placed in a 3 L stainless steel container, heated to 90 ° C., and stirred for 10 minutes with a homomixer (Mark II f model manufactured by Tokushu Kika Kogyo Co., Ltd.). Next, this dispersion was heated to 99 ° C., and circulation emulsification was started under a pressure of 45 MPa using a homogenizer (manufactured by Gorin Co., Ltd., 15-M-8PA type). ) To 240 nm to prepare a silicone wax dispersion B2 (emulsion solid content concentration = 27.3%).

<Preparation of polymer primary particle dispersion B2>
23.3 parts (466 g) of silicone wax dispersion B2 was added to a reactor (inner volume 21 L, inner diameter 250 mm, height 420 mm) equipped with a stirrer (three blades), a heating / cooling device, and each raw material / auxiliary charging device. ), 1.0 part of 20% DBS aqueous solution and 324 parts of demineralized water were added, the temperature was raised to 90 ° C. under a nitrogen stream, and 3.2 parts of 8% aqueous hydrogen peroxide solution, 8% L (+) − with stirring. 3.2 parts of ascorbic acid aqueous solution was added all at once. The time point 5 minutes after the batch addition of these is defined as “polymerization start”.

  A mixture of the following “polymerizable monomers etc.” and “emulsifier aqueous solution” was added over 5 hours from the start of polymerization, and the following “initiator aqueous solution” was added over 6 hours from the start of polymerization. While stirring, the internal temperature was maintained at 90 ° C. for 1 hour.

[Polymerizable monomers, etc.]
92.5 parts of styrene (1850.0 g)
7.5 parts butyl acrylate
Acrylic acid 1.5 parts
0.6 parts of trichlorobromomethane

[Emulsifier aqueous solution]
20% DBS aqueous solution 1.0 part
67.0 parts of demineralized water

[Initiator aqueous solution]
18.9 parts of 8% hydrogen peroxide solution
8% by mass L (+)-ascorbic acid aqueous solution 18.9 parts

  After completion of the polymerization reaction, the mixture was cooled to obtain a milky white polymer primary particle dispersion B2. The volume average diameter (Mv) measured using Nanotrac was 290 nm, and the solid content concentration was 19.0% by mass.

<Preparation of Colorant Dispersion B>
Carbon black (Mitsubishi Chemical Co., Ltd.) manufactured by a furnace method with a 300 L internal volume equipped with a stirrer (propeller blade) and a toluene extract having an ultraviolet absorbance of 0.02 and a true density of 1.8 g / cm ³ Mitsubishi Carbon Black MA100S) 20 parts (40 kg), 20% DBS aqueous solution 1 part, nonionic surfactant (manufactured by Kao Corp., Emulgen 120) 4 parts, ion-exchanged water 75 parts with an electric conductivity of 2 μS / cm In addition, it was predispersed to obtain a pigment premix solution. The volume average diameter (Mv) of carbon black in the dispersion after pigment premixing measured with Nanotrac was 90 μm.

The pigment premix solution was supplied as a raw material slurry to a wet bead mill and subjected to one-pass dispersion. The stator inner diameter was 75 mmφ, the separator diameter was 60 mmφ, the distance between the separator and the disk was 15 mm, and zirconia beads having a diameter of 100 μm (true density 6.0 g / cm ³ ) were used as the dispersing medium. Since the effective internal volume of the stator is 0.5 L and the filling volume of the media is 0.35 L, the media filling rate is 70% by mass. The pigment premix liquid is continuously supplied from the supply port at a supply speed of 50 L / hr by a non-pulsating metering pump, and the rotor rotation speed is constant (peripheral speed at the rotor tip is 11 m / sec), and continuously from the discharge port. To obtain a black colorant dispersion B. The volume average diameter (Mv) of the colorant dispersion B measured with Nanotrac was 150 nm, and the solid content concentration was 24.2% by mass.

<Manufacture of toner mother particle B>
Using the following components, toner base particles B were produced by carrying out the following aggregation processes (core material aggregation process, shell coating process), circularization process, washing process, and drying process.
Polymer primary particle dispersion B1 90 parts as solid content (958.9 g as solid content)
Polymer primary particle dispersion B2 10 parts as solid content
Colorant dispersion B 4.4 parts as colorant solids
20% DBS aqueous solution In the core material agglomeration step, the solid content is 0.15 parts
20% DBS aqueous solution In the rounding process, 6 parts as solid content

○ Core material aggregation process
Polymer primary particle dispersion B1 and 20% DBS aqueous solution are charged into a mixer (volume 12 L, inner diameter 208 mm, height 355 mm) equipped with a stirrer (double helical blade), heating / cooling device and raw material / auxiliary charging device. The mixture was uniformly mixed for 10 minutes at an internal temperature of 10 ° C. Then at an internal temperature of 10 ° C., allowed to stir at 280 rpm, a 5 mass% aqueous solution of potassium _sulfate, 0.12 parts of a continuously added over 1 minute as K 2 SO _4, the colorant dispersion B 5 The mixture was continuously added over a minute and mixed uniformly at an internal temperature of 10 ° C.

  Thereafter, 100 parts of demineralized water was continuously added over 30 minutes, and then the internal temperature was raised to 48.0 ° C. over 67 minutes (0.5 ° C./min) while maintaining the rotational speed of 280 rpm. Next, after raising the temperature by 1 ° C. every 30 minutes (0.03 ° C./min), hold at 54.0 ° C., measure the volume median diameter (Dv50) using a multisizer, and grow to 5.15 μm. It was.

The stirring conditions at this time are as follows.
(A) Diameter of the stirring vessel (as a so-called general cylindrical shape): 208 mm
(B) Height of stirring container: 355 mm
(C) Peripheral speed at the tip of the stirring blade: 280 rpm, that is, 2.78 m / sec.
(D) Shape of stirring blade: Double helical blade (diameter 190mm, height 270mm, width 20mm)
(E) Position of the blade in the stirring vessel: 5 mm above the bottom of the vessel.

○ Shell coating process
Thereafter, the polymer primary particle dispersion B2 was continuously added over 6 minutes while maintaining the internal temperature at 54.0 ° C. and the rotation speed of 280 rpm, and was maintained as it was for 60 minutes. At this time, the Dv50 of the particles was 5.34 μm.

○ Circularization process
Subsequently, the temperature was raised to 83 ° C. while adding a mixed aqueous solution of 20% DBS aqueous solution (6 parts as a solid content) and 0.04 part of water over 30 minutes, and then the temperature was raised by 1 ° C. every 30 minutes. The temperature was raised to 0 ° C., and heating and stirring were continued under these conditions until the average circularity reached 0.939 over 3.5 hours. Then, it cooled to 20 degreeC over 10 minutes, and obtained the slurry. At this time, the Dv50 of the particles was 5.33 μm and the average circularity was 0.937.

○ Cleaning process
The obtained slurry was extracted and subjected to suction filtration with an aspirator using filter paper of type 5 C (No5C manufactured by Toyo Roshi Kaisha, Ltd.). The cake remaining on the filter paper is transferred to a stainless steel container having an internal volume of 10 L equipped with a stirrer (propeller blade), and 8 kg of ion exchange water having an electric conductivity of 1 μS / cm is added and stirred uniformly at 50 rpm. Thereafter, stirring was continued for 30 minutes.

  Thereafter, the filter paper was suction filtered with an aspirator again using Type 5 C (Toyo Filter Paper No. 5C) filter paper, and the solid matter remaining on the filter paper was again equipped with a stirrer (propeller blade) and had an electrical conductivity of 1 μS / cm. It was transferred to a container with an internal volume of 10 L containing 8 kg of ion-exchanged water, and uniformly dispersed by stirring at 50 rpm and kept stirring for 30 minutes. When this process was repeated 5 times, the electrical conductivity of the filtrate was 2 μS / cm.

○ Drying process
The solid material obtained here was spread on a stainless steel bat so as to have a height of 20 mm, and dried in a blow dryer set at 40 ° C. for 48 hours to obtain toner mother particles B.

<Manufacture of toner>
External Addition Step A toner was prepared by mixing and sieving in the same manner as in Example 1 except that the toner base particles A were replaced with the toner base particles B. Incidentally, BET specific surface area measured by the external additive alone, H30TD silica 144.4m ² / g, the HAP-05NP calcium phosphate fine powder was 26.47m ² / g.

  The measured values for the toner obtained here are summarized in Table 1.

  The above-mentioned toner was evaluated for actual shooting as described above. The image quality was good up to 7000 sheets, but the image was partially faded thereafter. Since the weight reduction (toner consumption) of the cartridge was larger than that in Example 1, it did not reach 8000 sheets, and it was determined that the toner ran out and the running was terminated. Adhesion of toner and white external additive was observed on the charging roller. Compared with Example 1, the amount of toner consumed was large, and fog was seen on a white background. Further, the amount of toner scattering was greater than that in Example 1, and the casing under the developing roller was soiled with toner.

Comparative Example 3
<Manufacture of toner>
External Addition Step A toner was prepared by mixing and sieving in the same manner as in Comparative Example 1 except that the toner base particles A were replaced with the toner base particles B. The mixing ratio of the mother particles and the external additive is the same as that in Example 1. Incidentally, BET specific surface area measured by the external additive alone, H30TD silica 144.4m ² / g, the HAP-05NP calcium phosphate fine powder was 26.47m ² / g.

  The measured values for the toner obtained here are summarized in Table 1.

  The above-mentioned toner was evaluated for actual shooting as described above. Initially, the image quality at 500 sheets and 1000 sheets was good. There was no toner scattering, and no image defects or other problems were observed during the flow of the 5% pattern during the image check. However, the toner was stained with toner and silica on the charging roller at 1000 sheets. Therefore, when a 5% pattern was further flowed, toner smearing occurred on the white background of the printed material at about 1200 sheets. Dirt is generated at a period that coincides with the circumference of the charging roller, and is an image defect due to charging failure due to dirt on the charging roller. The evaluation was stopped here.

Comparative Example 4
<Manufacture of toner mother particles C>
In the agglomeration process (core material agglomeration process / shell coating process), circularization process, washing process, and drying process of “manufacturing toner toner particles B”, “core material agglomeration process”, “shell coating process”, and “circularization process” The toner base particles C were obtained in the same manner as in “Production of toner base particles A” in Example 1 except that “” was changed as follows.

○ Core material aggregation process
Polymer primary particle dispersion A1 and 20% in a mixer (volume 12 L, inner diameter 208 mm, height 355 mm) equipped with a stirring device (double helical blade), heating / cooling device, concentrating device, and each raw material / auxiliary charging device An aqueous DBS solution was charged and mixed uniformly at an internal temperature of 10 ° C. for 10 minutes. Subsequently, the mixture was stirred at 280 rpm at an internal temperature of 10 ° C., and 0.12 part of a 5 mass% aqueous solution of potassium sulfate was continuously added over 1 minute, and then the colorant dispersion B was continuously added over 5 minutes. Mix evenly at a temperature of 10 ° C. Thereafter, 100 parts of demineralized water was continuously added over 30 minutes, and the internal temperature was raised to 34.0 ° C. over 40 minutes (0.6 ° C./min) with the rotation speed being 280 rpm. Subsequently, it hold | maintained for 20 minutes, the volume median diameter (Dv50) was measured using the multisizer, and it was made to grow to 3.81 micrometers.

○ Shell coating process
Thereafter, the polymer primary particle dispersion A2 was added over 6 minutes while maintaining the internal temperature at 34.0 ° C. and the rotation speed of 280 rpm, and the state was maintained as it was for 90 minutes.

○ Circularization process
Subsequently, 20% DBS aqueous solution (6 parts as solid content) was added over 10 minutes while maintaining the rotation speed at 280 rpm (the same stirring speed as the aggregation process rotation speed), and then the temperature was raised to 76 ° C. over 30 minutes. The heating and stirring were continued until the average circularity reached 0.962. Then, it cooled to 20 degreeC over 10 minutes, and obtained the slurry.

<Manufacture of toner mother particles D>
Thereafter, 100 parts of the toner base particles A of Example 1 and 2 parts of the toner base particles C were mixed to obtain a toner base particle mixture D.

<Manufacture of toner>
External Addition Step A toner was prepared by mixing and sieving in the same manner as in Example 1 except that the toner base particles A were replaced with the toner base particles D. Incidentally, BET specific surface area measured by the external additive alone, H30TD silica 144.4m ² / g, the HAP-05NP calcium phosphate fine powder was 26.47m ² / g.

  The measured values for the toner obtained here are summarized in Table 1.

  The above-mentioned actual image evaluation was performed using the toner. During the initial check, smearing occurred at the trailing edge of the solid image. When the cartridge was opened and inspected, the toner was slightly attached to the cleaning blade at the position corresponding to the dirt. The photosensitive drum was removed, the cleaning blade was cleaned, and the toner was lightly dusted on the portion of the blade rubber that contacts the photosensitive drum, and the drum was mounted again to retake the image. The same stain was also generated in the same part, but there was no problem except for the solid image, so a running test was conducted. After that, similar stains occurred during the solid image check.

  Around 3000 sheets, a streak-like image defect occurred during running. The image defect disappeared when the printer was switched off and restarted. Further, when about 500 sheets were printed, a streak defect occurred, and the cartridge was disassembled. As a result, toner was observed in the circumferential direction of the charging roller at the position corresponding to the defect.

  Although the streak defect occurred or disappeared, running was performed up to 8000 sheets. When the cartridge was disassembled after running, adhesion of a plurality of streaky toners in the circumferential direction of the charging roller was observed. There was little adhesion of white external additive. While the toner streaks were thin, the image did not become defective, but when it became darker, the image became defective. However, the tested printer happened to run idle in the cleaning process irregularly, and this caused the toner streaks on the charging roller to be cleaned and the image defect to be improved. It was bad.

Example 3
<Manufacture of toner mother particles E>
The “core material aggregation process”, “shell coating process”, and “circularization process” in the aggregation process (core material aggregation process / shell coating process), circularization process, cleaning process, and drying process of “Manufacture of toner base particles A” The toner mother particles E were obtained in the same manner as in “Production of toner mother particles A” in Example 1 except that “A” was changed as follows.

○ Core material aggregation process
Polymer primary particle dispersion A1 and 20% in a mixer (volume 12 L, inner diameter 208 mm, height 355 mm) equipped with a stirring device (double helical blade), heating / cooling device, concentrating device, and each raw material / auxiliary charging device A DBS aqueous solution was charged and mixed uniformly at an internal temperature of 7 ° C. for 5 minutes. Subsequently, while maintaining the internal temperature at 7 ° C. and continuing stirring at 250 rpm, 0.52 part of 5 mass% aqueous solution of ferrous sulfate was added as FeSO ₄ · 7H ₂ O over 5 minutes, and then the colorant Dispersion A was added over 5 minutes, mixed uniformly at an internal temperature of 7 ° C., and a 0.5% by mass aqueous solution of aluminum sulfate was added dropwise over 8 minutes under the same conditions (based on the resin solid content). Solid content is 0.10 parts). Thereafter, the internal temperature was raised to 55.0 ° C. while maintaining the rotational speed of 250 rpm, the volume median diameter (Dv50) was measured using a multisizer, and grown to 5.86 μm.

○ Shell coating process
Thereafter, the polymer primary particle dispersion A2 was added over 3 minutes while maintaining the internal temperature at 55.0 ° C. and the rotation speed at 250 rpm, and held as it was for 60 minutes.

○ Circularization process
Subsequently, the rotational speed was reduced to 150 rpm (a peripheral speed of 1.56 m / sec at the tip of the stirring blade, a stirring speed reduced by 40% with respect to the rotational speed of the aggregation process), and then a 20% DBS aqueous solution (6 parts as solid content) was added. The mixture was added over 10 minutes, then heated to 84 ° C. over 30 minutes, and heating and stirring were continued until the average circularity reached 0.942. Thereafter, it was cooled to 30 ° C. over 20 minutes to obtain a slurry.

<Manufacture of toner>
External Addition Step Toner base particle A is replaced with toner base particle E, and instead of Clariant H30TD silica 1.75 parts by weight (26.25 g) Clariant H13TM silica 2.40 parts by weight (36.00 g) Example 1 except that the mixing time of the mother particles and silica was changed from 15 minutes to 25 minutes and the additional amount of HAP-05NP calcium phosphate fine powder was changed to 0.25 parts by weight (3.75 g). In the same manner, mixing and sieving were performed to prepare a toner. Incidentally, BET specific surface area measured by the external additive alone, H13TM silica 92.96m ² / g, the HAP-05NP calcium phosphate fine powder was 26.47m ² / g.

  The measured values for the toner obtained here are summarized in Table 1.

  The above-mentioned toner was evaluated for actual shooting as described above. There was no particular problem up to 8000 sheets, and the image quality was good. There was no toner scattering, and a small amount of toner and white external additive adhered to the charging roller, but no image defects or other problems were found. However, compared with Example 1, there was no problem, but the toner consumption was slightly higher and the white external additive was a little more adhered.

Example 4
<Manufacture of toner mother particles F>
In the agglomeration process (core material agglomeration process / shell coating process), circularization process, washing process, and drying process of “manufacturing toner toner particles B”, “core material agglomeration process”, “shell coating process”, and “circularization process” The toner base particles F were obtained in the same manner as in “Production of toner base particles B” in Example 3, except that “” was changed as follows.

○ Core material aggregation process
Polymer primary particle dispersion B1 and 20% in a mixer (volume 12 L, inner diameter 208 mm, height 355 mm) equipped with a stirring device (double helical blade), heating / cooling device, concentrating device, and each raw material / auxiliary charging device An aqueous DBS solution was charged and mixed uniformly at an internal temperature of 10 ° C. for 10 minutes. Subsequently, the mixture was stirred at 280 rpm at an internal temperature of 10 ° C., and 0.12 part of a 5 mass% aqueous solution of potassium sulfate was continuously added over 1 minute, and then the colorant dispersion B was continuously added over 5 minutes. Mix evenly at a temperature of 10 ° C. Thereafter, 0.5 part of demineralized water was continuously added over 26 minutes, and then the internal temperature was raised to 52.0 ° C. over 64 minutes (0.5 ° C./minute) with the rotation speed being 280 rpm. Subsequently, after raising the temperature by 1 ° C. over 30 minutes (0.03 ° C./min), the temperature was maintained for 130 minutes, and the volume median diameter (Dv50) was measured using a multisizer to grow to 6.60 μm. The stirring conditions at this time were the same as in Example 7.

○ Shell coating process
Thereafter, the polymer primary particle dispersion B2 was continuously added over 6 minutes while maintaining the internal temperature at 53.0 ° C. and the rotational speed of 280 rpm, and the state was maintained for 60 minutes. At this time, the Dv50 of the particles was 6.93 μm.

○ Circularization process
Subsequently, the temperature was raised 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, and then raised to 97 ° C. over 60 minutes. Then, heating and stirring were continued under these conditions until the average circularity reached 0.945. Then, it cooled to 20 degreeC over 10 minutes, and obtained the slurry. At this time, the Dv50 of the particles was 6.93 μm and the average circularity was 0.945. The washing / drying steps were performed in the same manner as in Example 7.

<Manufacture of toner>
External Addition Step Toner base particle A is replaced with toner base particle F, the addition amount of Clariant H30TD silica is 1.25 parts by weight (18.75 g), and the addition amount of HAP-05NP calcium phosphate fine powder is 0.00. A toner was prepared by mixing and sieving in the same manner as in Example 1 except that the amount was changed to 2 parts by weight (3.00 g).

  The measured values for the toner obtained here are summarized in Table 1.

  The above-mentioned toner was evaluated for actual shooting as described above. There was no particular problem up to 8000 sheets, and the image quality was good. Although a very small amount of toner and white external additive adhered to the charging roller, there was no toner scattering.

Comparative Example 5
Using the toner base particles F used in Example 4, the following tests were performed.

<Manufacture of toner>
External Addition Step Toner base particle A is replaced with toner base particle F, the addition amount of Clariant H30TD silica is 1.25 parts by weight (6.25 g), and the addition amount of HAP-05NP calcium phosphate fine powder is 0.00. A toner was prepared by mixing and sieving in the same manner as in Comparative Example 1 except that the amount was changed to 2 parts by weight (1.00 g). The mixing ratio of the base particles and the external additive is the same as in Example 4.

  The measured values for the toner obtained here are summarized in Table 1.

  The toner was tested in the live-action evaluation as described above. Dirt was seen on the white background from around 4500 sheets. The stain coincided with the charging roller cycle. Since it deteriorated further, it ended with 6000 sheets. Compared with Example 1, the charging roller had much white external additive attached thereto. A large amount of external additive adhered to the charging roller, resulting in poor charging and appearing in the image.

Comparative Example 6
<Manufacture of toner mother particle G>
The “core material aggregation process”, “shell coating process”, and “circularization process” in the aggregation process (core material aggregation process / shell coating process), circularization process, cleaning process, and drying process of “Manufacture of toner base particles A” The toner mother particles G were obtained in the same manner as in “Production of toner mother particles A” in Example 1 except that “A” was changed as follows.

○ Core material aggregation process
Polymer primary particle dispersion A1 and 20% in a mixer (volume 12 L, inner diameter 208 mm, height 355 mm) equipped with a stirrer (double helical blade), heating / cooling device, concentration device, and each raw material / auxiliary charging device A DBS aqueous solution was charged and mixed uniformly at an internal temperature of 7 ° C. for 5 minutes. Subsequently, while maintaining the internal temperature at 21 ° C. and continuously stirring at 250 rpm, 0.52 parts of FeSO ₄ .7H ₂ O as a 5 mass% aqueous solution of ferrous sulfate was added all at once in 5 minutes, and then the colorant was dispersed. Liquid A was added all at once in 5 minutes, mixed uniformly at an internal temperature of 7 ° C., and 0.5 mass% aqueous aluminum sulfate solution was added in 8 seconds under the same conditions (solid to resin solids). Min is 0.10 parts). Thereafter, the internal temperature was raised to 57.0 ° C. while maintaining the rotational speed of 250 rpm, and the volume median diameter (Dv50) was measured using a multisizer to grow to 6.85 μm.

○ Shell coating process
Thereafter, with the internal temperature of 57.0 ° C. and the rotation speed of 250 rpm, the polymer primary particle dispersion A2 was added all at once in 3 minutes, and held as it was for 60 minutes.

○ Circularization process
Subsequently, 20% DBS aqueous solution (6 parts as solid content) was added over 10 minutes while maintaining the rotation speed at 250 rpm (circumferential speed 2.59 m / sec at the tip of the stirring blade, the same stirring speed as the aggregation process rotation speed). Thereafter, the temperature was raised to 87 ° C. over 30 minutes, and heating and stirring were continued until the average circularity reached 0.942. Thereafter, the mixture was cooled to 30 ° C. over 20 minutes to obtain a slurry.

<Manufacture of toner>
External Addition Step Toner base particle A is replaced with toner base particle G, the addition amount of Clariant H30TD silica is 1.25 parts by weight (18.75 g), and the addition amount of HAP-05NP calcium phosphate fine powder is 0.00. A toner was prepared by mixing and sieving in the same manner as in Example 1 except that the amount was changed to 2 parts by weight (3.00 g).

  The measured values for the toner obtained here are summarized in Table 1.

  The toner was tested in the live-action evaluation as described above. During the initial check, the back edge of the solid image was slightly stained. When the cartridge was opened and inspected, the toner was slightly attached to the cleaning blade at the position corresponding to the dirt. When the photosensitive drum was removed, the cleaning blade was cleaned, the toner was lightly dusted on the portion of the blade rubber that contacts the photosensitive drum, the drum was mounted again, and the image was taken again. In the subsequent image quality check, the trailing edge was smeared about once every three times in the solid image pattern, but a running test was performed up to 8000 sheets.

  Finally, the cartridge was opened and observed. Toner scattering and adhesion of toner and white external additive were observed on the charging roller. Although actual photographs were taken up to 8000 sheets, adhesion of toner and white external additive was observed on the charging roller.

  The toner of the present invention is less likely to cause smearing, residual image (ghost), blurring (solid followability), etc. on the white background of the image, suppresses toner scattering, has good cleaning properties, and has a sharp charge amount distribution. Therefore, it has excellent image stability, narrow particle size distribution, and even if the toner particle size is reduced, the amount of fine powder is small, so the bulk density is improved and the fixing property is good, so it can be used for general printers, copiers, etc. Of course, it is also widely used in image forming methods by high resolution, long life, and high speed printing that have been developed in recent years.

1 is a schematic diagram illustrating an example of a non-magnetic one-component toner developing device using the toner of the present invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electrostatic latent image carrier 2 Toner conveyance member 3 Elastic blade (toner layer thickness regulating member)
4 Sponge roller (toner replenishment auxiliary member)
5 Stirrer blade 6 Toner 7 Toner hopper

Claims (25)

A toner used in an electrostatic charge image developing method for cleaning a transfer residual toner with a cleaning blade, wherein the toner is obtained by externally adding an external additive to toner base particles, and the “BET specific surface area of the toner” is expressed as “ The value divided by the spherical assumed specific surface area calculated from the volume median diameter (Dv50) of the toner is 3.0 or less, and the volume median diameter (Dv50) of the toner is 4.0 μm or more and 7.0 μm or less. And a toner wherein the relationship between the volume median diameter (Dv50) and the number% (Dns) of toner having a particle diameter of 2.00 μm to 3.56 μm satisfies the following formula (1).
(1) Dns ≦ 0.233EXP (17.3 / Dv50)
[In the formula, Dv50 represents the volume median diameter (μm) of the toner, and Dns represents the number% of the toner having a particle diameter of 2.00 μm to 3.56 μm. ] The toner according to claim 1, wherein the relationship between the volume median diameter (Dv50) and the number% (Dns) of toner having a particle diameter of 2.00 μm to 3.56 μm satisfies the following formula (2).
(2) Dns ≦ 0.110EXP (19.9 / Dv50) The toner according to claim 1, wherein the relationship between the volume median diameter (Dv50) and the number% (Dns) of toner having a particle diameter of 2.00 μm to 3.56 μm satisfies the following formula (3).
(3) 0.0517EXP (22.4 / Dv50) ≦ Dns   The toner according to any one of claims 1 to 3, wherein the toner has a volume median diameter (Dv50) of 5.0 µm or more.   5. The toner according to claim 1, wherein the number% (Dns) of the toner having a particle diameter of 2.00 μm to 3.56 μm is 6% by number or less.   The toner according to claim 1, comprising toner base particles formed in an aqueous medium.   The toner according to any one of claims 1 to 6, comprising toner base particles produced by polymerization in an aqueous medium.   The toner according to any one of claims 1 to 7, comprising toner base particles produced by an emulsion polymerization aggregation method.   The toner according to any one of claims 1 to 8, wherein the toner base particles are obtained by fixing or adhering resin fine particles to the core particles.   The toner according to claim 9, wherein the resin fine particles contain a wax.   The core particles are composed of at least polymer primary particles, and the ratio of the total amount of polar monomers in 100% by mass of all polymerizable monomers constituting the binder resin as the resin fine particles constitutes the core particles. The toner according to claim 9 or 10, wherein the toner is smaller than a ratio of a total amount of polar monomers in 100% by mass of all polymerizable monomers constituting the binder resin as polymer primary particles.   The toner according to any one of claims 1 to 11, wherein the wax is contained in an amount of 4 to 20 parts by mass with respect to 100 parts by mass of the toner.   The toner according to any one of claims 1 to 12, which is used in an image forming apparatus having a developing process speed of 100 mm / second or more on a latent image carrier. 14. The toner according to claim 1, wherein the toner is used in an image forming apparatus that satisfies the following formula (4).
(4) Guaranteed lifetime number of sheets (sheets) x printing rate ≧ 400 (sheets) of a developer filled with developer   The toner according to claim 1, wherein the toner is used in an image forming apparatus having a resolution of 600 dpi or more on a latent image carrier.   The toner according to any one of claims 1 to 15, wherein the toner is obtained without a step of removing a part of particles having a volume median diameter (Dv50) or less.   The toner according to claim 1, wherein the standard deviation of the charge amount is 1.0 or more and 2.0 or less.   18. The toner according to claim 1, wherein an external additive is added to the toner base particles in an amount of 1% by mass or more.   19. The toner according to claim 1, wherein at least one of the external additives is an inorganic fine powder.   The toner according to any one of claims 1 to 19, wherein at least one of the external additives is hydrophobic silica.   2. The external addition is performed while maintaining the temperature of the inner wall surface of the external addition device used for external addition in a range of (glass transition temperature of the toner—15 ° C.) to (glass transition temperature of the toner). The toner according to any one of claims 20 to 20.   A developing process for attaching toner to the electrostatic image on the surface of the electrostatic charge image holding member, a transfer process for transferring the toner on the electrostatic charge image holding member to a transfer material, and then, on the electrostatic charge image holding member in the transfer process. An image forming method comprising: a cleaning step of cleaning a transfer residual toner remaining on the toner, wherein the toner is the toner according to any one of claims 1 to 21, and the cleaning step. In the image forming method, the toner remaining on the transfer is cleaned by bringing a cleaning blade into contact with the electrostatic charge image holding member.   The image forming method according to claim 22, further comprising a step of uniformly charging the electrostatic charge image holding member, wherein the contact charging member is used in the step of uniformly charging.   An image forming apparatus using the toner according to any one of claims 1 to 21.   An image forming apparatus using the image forming method according to claim 22 or 23.

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