JP4080409B2 - Electrophotographic toner and image forming apparatus - Google Patents

Description

  The present invention relates to a toner used as a developer for developing an electrostatic image in electrophotography, electrostatic recording, electrostatic printing, and the like, a production method thereof, an image forming method using the toner, and the toner. The present invention relates to a process cartridge having developing means. Furthermore, it is loaded with electrophotographic toners, electrophotographic developers, and electrophotographic developers used in electrophotographic developing apparatuses such as copiers, laser printers, plain paper fax machines, etc. using direct or indirect electrophotographic developing systems. The present invention relates to a process cartridge and an image forming method. Further, electrophotographic toners used in electrophotographic developing apparatuses such as full-color copying machines, full-color laser printers, full-color plain paper fax machines using direct or indirect electrophotographic multicolor image development methods, electrophotographic developers, The present invention relates to a process cartridge loaded with a photographic developer and an image forming method.

  Conventionally, a latent image formed electrically or magnetically in an electrophotographic apparatus, an electrostatic recording apparatus or the like has been visualized with toner. For example, in electrophotography, an electrostatic charge image (latent image) is formed on a photoreceptor, and then the latent image is developed with toner to form a toner image. The toner image is usually transferred onto a transfer material such as paper, and then fixed onto the transfer material such as paper by a method such as heating. The toner used for developing an electrostatic image is generally colored particles containing a colorant, a charge control agent, and other additives in a toner binder. And suspension polymerization.

  In the pulverization method, a colorant, a charge control agent, an offset preventive agent, and the like are melt-mixed and uniformly dispersed in a thermoplastic resin, and the resulting composition is pulverized and classified to produce a toner. According to the pulverization method, a toner having some excellent characteristics can be produced, but there is a limitation in the selection of the toner material. For example, the composition obtained by melt mixing must be capable of being pulverized and classified by economically usable equipment. Because of this necessity, the melt-mixed composition must be made sufficiently brittle. For this reason, when the above composition is actually pulverized into particles, a high-range particle size distribution is likely to be formed, and when attempting to obtain a copy image with good resolution and gradation, for example, The fine powder of 5 μm or less and the coarse powder of 20 μm or more must be removed by classification, and there is a disadvantage that the yield becomes very low. Further, in the pulverization method, it is difficult to uniformly disperse compounding agents such as a colorant and a charge control agent in the thermoplastic resin. The uneven dispersion of the compounding agent adversely affects the fluidity, developability, durability, image quality, and the like of the toner.

  In recent years, in order to overcome these problems in the pulverization method, a method for producing a toner for developing an electrostatic image by polymerizing a monomer has been proposed and implemented. For example, toner particles are obtained by a suspension polymerization method. However, the toner particles obtained by the suspension polymerization method are generally spherical and have the disadvantage of poor cleaning properties. If the cleaning performance becomes poor, residual toner remains on the photoconductor, and if it accumulates, it causes image smudges, and also contaminates the charging roller that contacts and charges the photoconductor, causing the original charge to occur. The ability will not be demonstrated.

  For this reason, a method for obtaining irregular toner particles by associating resin fine particles obtained by an emulsion polymerization method has been proposed (see Patent Document 1). However, the toner particles obtained by the emulsion polymerization method have a problem that a large amount of the surfactant remains on the surface and inside the particles even after the water washing step. As a result, the charging stability of the toner is impaired, the charge amount distribution is widened, and the image is smeared. The remaining surfactant contaminates the photoreceptor, the charging roller, the developing roller, etc., and the original function cannot be exhibited.

  On the other hand, in the process of fixing the image after transfer to transfer paper or the like by a contact heating method using a heating roller or the like, the toner particles do not migrate to the fixing roller or the like even under high temperature conditions, and the releasability is improved. A good thing (hereinafter referred to as “offset resistance”) is required. Here, the offset resistance can be improved by the presence of a release agent on the toner particle surface. In contrast to this, a method has been proposed in which not only the resin fine particles are contained in the toner particles but also the resin fine particles are unevenly distributed on the surface of the toner particles, thereby improving the offset resistance (Patent Document 2,). 3). However, the minimum fixing temperature increases, and the low-temperature fixability (that is, energy-saving fixability) is not sufficient. Further, the method of obtaining irregular toner particles by associating resin fine particles obtained by the emulsion polymerization method causes the following problems. When releasing agent fine particles are associated with each other in order to improve offset resistance, the releasing agent fine particles are taken into the toner particles, and as a result, the offset resistance cannot be sufficiently improved. . Resin fine particles, release agent fine particles, colorant fine particles, etc. are randomly fused to constitute toner particles, so that there is variation in composition (content ratio of constituent components) and molecular weight of constituent resins among the obtained toner particles. As a result, the toner particles have different surface characteristics, and a stable image cannot be formed over a long period of time. Further, in a low-temperature fixing system that requires low-temperature fixing, there is a problem that fixing temperature range cannot be ensured due to occurrence of fixing inhibition due to resin fine particles unevenly distributed on the toner surface.

  On the other hand, a new production method called a dissolution suspension method (EA; Emulsion-Aggregation method) has recently been proposed (see Patent Document 4). Whereas the suspension polymerization method forms polymer particles from monomers, this method is a method of granulating from a polymer dissolved in an organic solvent or the like, and expands the range of resin selection, polarity controllability, etc. There is an advantage. In addition, there is an advantage that the toner structure can be controlled (preparation of the core / shell structure), but the shell structure is a resin-only layer intended to reduce the exposure of pigments and wax to the surface. In particular, the surface state is not devised, nor is such a structure (see Non-Patent Document 1). Therefore, although it has a shell structure, the toner surface is an ordinary resin, and there is no particular ingenuity. When aiming at lower temperature fixing, it is not sufficient in terms of heat-resistant storage stability and environmental charge stability. Met.

  In addition, in any of the suspension polymerization method, emulsion polymerization method and dissolution suspension method, it is common to use a styrene-acrylic acid ester copolymer. Distribution and shape control were difficult. In addition, there was a limit to fixability when aiming at lower temperature fixing.

  In the field of electrophotography, high image quality has been studied from various angles, and among them, the recognition that toner diameter reduction and spheroidization are extremely effective is increasing. However, as the diameter of the toner is reduced, the transferability and the fixing property are lowered, and a tendency to become a poor image is observed. On the other hand, it is known that transferability is improved by making the toner spherical (see Patent Document 5). Under such circumstances, further speeding up of image formation is desired in the field of color copiers and color printers. The “tandem method” is effective for speeding up (see, for example, Patent Document 6). The “tandem method” is a method of obtaining a full-color image on a transfer sheet by sequentially superimposing and transferring an image formed by an image forming unit on a single transfer sheet conveyed to a transfer belt. A tandem color image forming apparatus has a variety of transfer papers that can be used, has high quality of a full color image, and has excellent characteristics that a full color image can be obtained at a high speed. In particular, the characteristic that a full color image can be obtained at a high speed is a characteristic that is not found in other color image forming apparatuses. On the other hand, attempts have been made to achieve high speed while improving image quality using spherical toner. However, in order to cope with higher speeds, quick fixability is required, but a toner that has both fast fixability and low temperature fixability with a spherical toner has not been realized so far.

  Also, during storage and transportation after toner production, the toner may be exposed to harsh environments such as high temperature and high humidity and low temperature and low humidity. Is not aggregated, and there is a demand for a toner that does not cause deterioration in charging characteristics, fluidity, transferability, fixability, or the like, or has extremely low storage stability. So far no means have been found.

  On the other hand, a method of mixing toner particles and inorganic powders such as various metal oxides for the purpose of improving the flow characteristics and charging characteristics of the toner has been proposed. The inorganic powders are called external additives. It is. If necessary, surface treatment with a specific silane coupling agent, titanate coupling agent, silicone oil, organic acid, etc. for the purpose of modifying the hydrophobicity, charging characteristics, etc. of the surface of the inorganic powder, and a specific resin A method of coating has also been proposed. As the inorganic powder, for example, silicon dioxide (silica), titanium dioxide (titania), aluminum oxide, zinc oxide, magnesium oxide, cerium oxide, iron oxide, copper oxide, tin oxide and the like are known. In particular, silica particles obtained by reacting silica or titanium oxide fine particles with an organosilicon compound such as dimethyldichlorosilane, hexamethyldisilazane, or silicone oil to replace the silanol groups on the surface of the silica fine particles with organic groups to make them hydrophobic are used.

  However, these external additives are buried in the toner base or released from the toner surface due to mechanical stress inside the developing machine or the like due to repeated use of a large number of sheets for a long period of time, resulting in deterioration of toner fluidity and charging characteristics. To do. As a result, an appropriate image density may not be obtained, or background stains may be caused. Therefore, it is an important subject to impart appropriate fluidity and charging ability to the toner base itself. In a toner using a toner binder obtained by extending a functional group-containing polyester resin, it has been proposed to improve toner fluidity by using a specific prepolymer (see Patent Documents 7 and 8). However, it is inferior in the selectivity of the material, so that sufficient fluidity cannot be obtained to solve the above problems, and there has been no means so far having both charging characteristics.

Japanese Patent No. 2537503 JP 2000-292773 A JP 2000-292978 A Japanese Patent No. 3141784 JP 9-258474 A JP-A-5-341617 JP 2000-250265 A JP 2000-298376 A Takao Ishiyama and two others "Characteristics and Future Prospects of New Toner" (4th Joint Imaging Society of Japan Society of Electrostatics (2000.7.29))

  In view of the above-mentioned problems of the prior art, an object of the present invention is to provide a sharp charge amount distribution, which does not contaminate the charging device, the developing device, the photosensitive member, and the intermediate transfer member, and has a high quality image, particularly for a long period of time. An object of the present invention is to provide an electrophotographic toner capable of obtaining an appropriate image density even when a large number of sheets are repeatedly used and generating very little background stain, and an image forming method using the same. Also, an electrophotographic toner having excellent fluidity and capable of forming a stable image with no image blur and dust and no transfer omission on any transfer medium, and an image forming method using the same Is to provide. Another object of the present invention is to provide a toner that is compatible with a low-temperature fixing system, has good offset resistance, and does not contaminate the fixing device and the image.

  As a result of intensive studies to solve the above problems, the present inventors dispersed an organic solvent solution / dispersion containing a functional group-containing polyester resin in an aqueous medium containing resin fine particles, and obtained an active hydrogen-containing compound. In the toner obtained through the step of elongation reaction and / or cross-linking reaction with resin, the resin fine particles are dispersed in the organic solvent solution / dispersion liquid, and the resin fine particles are contained in the toner, whereby flow characteristics are obtained. In addition, the inventors have found that a toner capable of solving the above-mentioned problems with excellent charging characteristics and sharp particle size distribution and charge amount distribution can be obtained, and the present invention has been completed based on this finding.

  That is, in the present invention, first, an organic solvent phase in which at least a functional group-containing polyester resin is dissolved and resin fine particles ((A) are dispersed) and an active hydrogen-containing compound are combined with resin fine particles ( B) is dispersed in an aqueous medium phase in which the functional group-containing polyester resin and the active hydrogen-containing compound are subjected to an extension reaction and / or a crosslinking reaction. An electrophotographic toner comprising the resin fine particles (A) therein, and a two-component developer composed of an electrophotographic toner and a carrier.

  In the second aspect of the present invention, the electrostatic image on the electrostatic image carrier is developed by an electrostatic image developing means to form a toner image, and the transfer means is provided on the surface of the electrostatic image carrier via a recording material. Provided is an image forming apparatus that uses the electrophotographic toner or the two-component developer as a developer in an image forming apparatus that abuts and electrostatically transfers the toner image to the recording material.

  Thirdly, the present invention is a process cartridge which constitutes a part of the image forming apparatus and is detachable, and at least the electrostatic charge image carrier and the developing means are integrally supported inside. And a developing cartridge in which the developing means holds the toner for electrophotography.

  According to the present invention, the charge amount distribution is sharp, the charging device, the developing device, the photosensitive member and the intermediate transfer member are not contaminated, and it is appropriate to use a high-quality image, particularly a large number of sheets repeatedly for a long time. An electrophotographic toner that provides image density and generates very little background stains, and has excellent fluidity, and can produce a stable image that is free of image blurring and dust on any transfer media. An electrophotographic toner that can be formed with good reproducibility, and a toner that is compatible with a low-temperature fixing system, has good offset resistance, and does not contaminate a fixing device and an image can be provided. In addition, by using the toner, an image forming apparatus having high-quality image forming performance can be provided.

Hereinafter, the present invention will be described in detail.
[Organic solvent phase]

<Organic solvent>
The organic solvent used for the formation of the organic solvent phase in the present invention can dissolve at least the functional group-containing polyester resin described below, and can disperse the resin fine particles (A) described below uniformly. It can be used without any particular limitation. In particular, since the organic solvent needs to be distilled off after the dispersion step of the organic solvent phase in the aqueous medium phase described later, the boiling point is less than 150 ° C. in order to facilitate the distillation step. It is preferable to use a volatile organic solvent. Specific examples of the organic solvent used in the present invention include, for example, toluene, xylene, benzene, carbon tetrachloride, methylene chloride, 1,2-dichloroethane, 1,1,2-trichloroethane, trichloroethylene, chloroform, monochlorobenzene, acetic acid. Examples thereof include methyl, ethyl acetate, methyl ethyl ketone, acetone, tetrahydrofuran and the like, and these can be used singly or in combination of two or more. Among these, from the viewpoint of safety, methyl acetate and ethyl acetate which are non-halogen solvents are particularly preferable.
The amount of solvent used relative to 100 parts of the toner composition is usually 40 to 300 parts, preferably 60 to 140 parts, and more preferably 80 to 120 parts.

<Functional group-containing polyester resin>
The functional group-containing polyester resin used in the present invention is dissolved in the organic solvent and, as will be described later, undergoes an extension reaction and / or a crosslinking reaction with an active hydrogen-containing compound to be described later in an aqueous medium, resulting in a higher molecular weight toner. It is a component that forms a binder.

  Examples of the functional group-containing polyester resin include polyester prepolymers having a functional group that reacts with active hydrogen such as an isocyanate group. The polyester prepolymer preferably used in the present invention is the polyester prepolymer (A) having this isocyanate group.

  This polyester prepolymer (A) is produced by reacting a polyisocyanate (PIC) with a polyester having a polycondensate of a polyol (PO) and a polycarboxylic acid (PC) and having an active hydrogen group. Examples of the active hydrogen group possessed by the polyester include a hydroxyl group (alcoholic hydroxyl group and phenolic hydroxyl group), an amino group, a carboxyl group, a mercapto group, and the like. Among these, an alcoholic hydroxyl group is preferable.

  Examples of the polyol include diol (DIO) and trivalent or higher polyol (TO), and DIO alone or a mixture of DIO and a small amount of TO is preferable.

  Diols include alkylene glycols (ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, neopentyl glycol, 1,5-pentanediol, 1,6-hexanediol, etc.) Alkylene ether glycol (diethylene glycol, triethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, etc.); alicyclic diol (1,4-cyclohexanedimethanol, hydrogenated bisphenol A, etc.); bisphenol (Bisphenol A, bisphenol F, bisphenol S, etc.); alkylene oxides of the alicyclic diols (ethylene oxide, propylene oxide, butylene) Kisaido etc.) adducts; alkylene oxide (ethylene oxide of the bisphenols, propylene oxide, butylene oxide, etc.) adducts. Among these, alkylene glycols having 2 to 12 carbon atoms and alkylene oxide adducts of bisphenols are preferable. Particularly preferred are alkylene oxide adducts of bisphenols and combinations thereof with alkylene glycols having 2 to 12 carbon atoms.

  Examples of the trihydric or higher polyol include 3 to 8 or higher polyhydric aliphatic alcohols (glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, sorbitol, etc.); trihydric or higher phenols (trisphenol PA, Phenol novolac, cresol novolac, etc.); alkylene oxide adducts of the above trivalent polyphenols and the like.

  Examples of the polycarboxylic acid (PC) include dicarboxylic acid (DIC) and trivalent or higher polycarboxylic acid (TC), and DIC alone or a combination of DIC and a small amount of TC is preferable.

  Dicarboxylic acids include alkylene dicarboxylic acids (succinic acid, adipic acid, sebacic acid, etc.); alkenylene dicarboxylic acids (maleic acid, fumaric acid, etc.); aromatic dicarboxylic acids (phthalic acid, isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid, etc.) ) And the like. Among these, preferred are alkenylene dicarboxylic acids having 4 to 20 carbon atoms and aromatic dicarboxylic acids having 8 to 20 carbon atoms.

  Examples of the trivalent or higher polycarboxylic acid include aromatic polycarboxylic acids having 9 to 20 carbon atoms (such as trimellitic acid and pyromellitic acid). The polycarboxylic acid may be subjected to a condensation reaction with a polyol as the acid anhydride or lower alkyl ester (methyl ester, ethyl ester, isopropyl ester, etc.) described above.

  In order to prepare a polyester having an alcoholic hydroxyl group at the terminal by a polycondensation reaction, the use ratio of the polyol component and the polycarboxylic acid component is equivalent ratio [OH] / [COOH] of hydroxyl group [OH] and carboxyl group [COOH]. In general, the ratio is 2/1 to 1/1, preferably 1.5 / 1 to 1/1, and more preferably 1.3 / 1 to 1.02 / 1.

  Examples of the polyisocyanate (PIC) used to prepare the polyester prepolymer (A) by reacting with the alcoholic hydroxyl group of the polyester include aliphatic polyisocyanates (tetramethylene diisocyanate, hexamethylene diisocyanate, 2,6-di-). Isocyanatomethyl caproate); alicyclic polyisocyanates (isophorone diisocyanate, cyclohexylmethane diisocyanate, etc.); aromatic diisocyanates (tolylene diisocyanate, diphenylmethane diisocyanate, etc.); araliphatic diisocyanates (α, α, α ′, α ′) -Tetramethylxylylene diisocyanate, etc.); isocyanurates; those obtained by blocking the polyisocyanate with phenol derivatives, oximes, caprolactam, etc .; and Combinations of two or more of these and the like.

  The use ratio of the polyisocyanate is usually 5/1 to 1/1, preferably 4/1, as an equivalent ratio [NCO] / [OH] of the isocyanate group [NCO] and the hydroxyl group [OH] of the polyester having a hydroxyl group. To 1.2 / 1, more preferably 2.5 / 1 to 1.5 / 1. If the equivalent ratio is too high, the low-temperature fixability of the obtained toner may be deteriorated. On the other hand, if the equivalent ratio is too low, the urea bond content in the reaction product with amines will be low, and the resulting toner will be resistant to hot offset. This is not preferable because the properties may deteriorate.

  The number of isocyanate groups contained per molecule in the polyester prepolymer (A) having an isocyanate group is usually 1 or more, preferably 1.5 to 3 on average, more preferably 1.8 to 2 on average. Five. If it is less than 1 per molecule, the molecular weight of the urea-modified polyester will be low, and the hot offset resistance will deteriorate.

  As described above, the polyester prepolymer (A) is used by being dissolved in an organic solvent phase. The amount used and the amount of the polyester prepolymer (A) is usually 1 to 80% by weight, preferably as the content in the toner base. Is 3 to 30% by weight, more preferably 3 to 25% by weight, and particularly preferably 5 to 20% by weight.

<Combination of non-reactive low molecular weight polyester>
In the present invention, as a toner binder component, not only the elongation reaction and / or crosslinking reaction product of the functional group-containing polyester resin and the active hydrogen compound described below, but also non-reactive polyester (PE) is contained in the organic solvent phase. It can be dissolved and used together. By using this PE in combination, the low-temperature fixability of the toner of the present invention and the glossiness when used in a full-color apparatus are improved, which is preferable to the case where the elongation reaction and / or crosslinking reaction product is used alone. Examples of PE include a polycondensate of a polyol and a polycarboxylic acid similar to the polyester used for the reaction with the polyisocyanate (PIC), and preferable ones are also the same as described above.

  Moreover, PE may be modified not only with unmodified polyester but also with a chemical bond other than a urea bond, for example, with a urethane bond. When formed into a toner, it is preferable in terms of low-temperature fixability and hot offset resistance that the elongation reaction and / or crosslinking reaction product and PE are at least partially compatible. Therefore, the polyester prepolymer (A) and PE preferably have similar compositions. When PE is contained in the organic solvent phase, the blending amount is usually 5/95 to 80/20, preferably 5/95 to 30/70 as the weight ratio of the polyester prepolymer (A) to PE, and more preferably Preferably it is 5 / 95-25 / 75, Most preferably, it is 7 / 93-20 / 80. When the weight ratio of the polyester prepolymer (A) is too low, hot offset resistance is deteriorated and it is difficult to achieve both heat-resistant storage stability and low-temperature fixability.

  The peak molecular weight measured by GPC (gel permeation chromatography) of PE is usually 1000 to 30000, preferably 1500 to 10000, more preferably 2000 to 8000. If the molecular weight is too low, the heat-resistant storage stability is deteriorated, whereas if it is too high, the low-temperature fixability is deteriorated. The hydroxyl value of PE is preferably 5 or more, more preferably 10 to 120, and particularly preferably 20 to 80. If the hydroxyl value is too low, it is difficult to achieve both heat-resistant storage stability and low-temperature fixability. Moreover, the acid value of PE is 1-30 normally, Preferably it is 5-20. If the acid value is too high, it tends to be negatively charged, which is not preferable.

  The organic solvent phase may further contain a toner binder other than those described above, for example, a conventionally known toner binder such as styrene resin, acrylic resin, epoxy resin, styrene-acrylic acid ester copolymer.

<Resin fine particles (A)>
The resin fine particles (A) are dispersed in the organic solvent phase and function mainly as an internal additive in the process of toner formation, and are the most important components characterizing the present invention.

  As the resin fine particles (A) used in the present invention, known ones can be used without particular limitation. For example, polystyrene, styrene- (meth) acrylic acid ester obtained by soap-free emulsion polymerization, suspension polymerization or dispersion polymerization. Copolymers, vinyl polymers such as (meth) acrylic acid ester polymers; polycondensation polymers such as polysiloxanes, benzoguanamine resins, and polyamides; thermosetting epoxy resins, phenol resins, unsaturated polyester resins, etc. Resin fine particles of a conductive resin. Among these, styrene- (meth) acrylic acid ester-based copolymers or (meth) acrylic acid ester-based polymers are particularly preferable because the effects of the present invention are exhibited. However, it is desirable that the resin fine particles do not dissolve in the organic solvent. For example, 1 part of the resin fine particles is added to 100 parts by weight of the organic solvent to be used, and the mixture is stirred for 12 hours in an environment of 25 ° C., and then filtered and dried. When the weight of the resin fine particles added to the organic solvent is Y (g), if the value of X / Y is 0.80 or more, the resin fine particles can sufficiently exhibit the effects of the present invention. These can be used singly or in combination of two or more. By containing the resin fine particles in the toner particles, the chargeability of the toner particles can be enhanced, the reversely charged toner particles can be reduced, and the background stain of the image can be reduced.

  The amount of the resin fine particles (A) added is preferably 0.1 to 30% by weight, more preferably 0.5 to 5% by weight as the content in the organic solvent phase. By setting the amount within this range, the toner base can be provided with good charging characteristics, and there is an effect of preventing the charging ability from being lowered due to the embedding or releasing of the external additive when the toner is strongly stirred and deteriorated. Further, the effect of the resin fine particles exposed on the toner surface as a lubricant is sufficiently exhibited, and the toner can have excellent fluidity. If the amount of the resin fine particles (A) added is too small, sufficient charging ability and fluidity are hardly exhibited. On the other hand, if the amount is too large, the amount of resin fine particles exposed on the toner surface increases and not only deteriorates the circularity of the toner particles, but also the resin fine particles act as a fixing inhibitor, so that the minimum fixing temperature increases and the low temperature Fixability is impaired.

  The average particle diameter of the resin fine particles dispersed in the organic solvent phase is preferably 0.15 to 2.0 μm, more preferably 0.15 to 0.40 μm. By setting the amount within this range, the spacer effect for preventing the aggregation of the toners is sufficiently exhibited, and the effect of preventing the external additive from being buried when the toner is stored at a high temperature or when the toner is vigorously stirred is exhibited. If the average particle size is too small, toner aggregation and external additives are liable to occur. On the other hand, if it is too large, not only the circularity of the toner particles is deteriorated, but also the minimum fixing temperature is increased and the low temperature fixing property is impaired. Also, the resin fine particles can be more effective if they are as spherical as possible.

  When these resin fine particles are used as an electrophotographic toner, they can be used singly or in combination of two or more kinds having different types and average particle diameters.

  The average particle diameter is a number average particle diameter. The particle size of the resin fine particles used in the present invention can be measured by a particle size distribution measuring apparatus using dynamic light scattering, for example, DLS-700 manufactured by Otsuka Electronics Co., Ltd. or Coulter N4 manufactured by Coulter Electronics. . However, when secondary agglomeration occurs in the resin fine particles as a raw material, it is difficult to dissociate the secondary agglomeration of the particles. Therefore, the particle size is directly determined from a photograph obtained by a scanning electron microscope or a transmission electron microscope. It is preferable to obtain. In this case, at least 100 resin fine particles are observed to determine the average value of the major axis, and this is used as the average particle diameter. The secondary aggregation is not particularly problematic because it is dissociated by mixing and kneading in an organic solvent phase.

  The glass transition point (Tg) of the resin fine particles (A) is preferably 40 to 130 ° C, more preferably 50 to 90 ° C. If the Tg is too low, the long-term storage stability in the toner storage environment deteriorates, and blocking occurs during storage or in the developing machine. On the other hand, if the Tg is too high, the resin fine particles exposed on the toner surface hinder the adhesiveness to the fixing paper, and the lower limit fixing temperature is undesirably increased.

<Combination of inorganic fine particles>
In the present invention, it is preferable to use together with the resin fine particles (A), inorganic fine particles dispersed in an organic solvent phase and functioning mainly as an internal additive in the process of toner formation. By using the inorganic fine particles, the fluidity and charging characteristics of the toner are further improved, and excellent effects such as the fact that the external additive is not buried even when the toner is stored at a high temperature or when the toner is vigorously stirred are exhibited. The average particle size of the inorganic fine particles dispersed in the organic solvent phase is preferably 5 nm to 2 μm, and particularly preferably 5 nm to 500 nm. Moreover, it is preferable that the specific surface area by BET method is 20-500 m < ² > / g.

The amount of the inorganic fine particles used is preferably 0.1 to 30% by weight, more preferably 0.5 to 10% by weight, as the content in the toner base particles.
By setting it within this range, the inorganic fine particles exposed on the toner surface improve the fluidity of the toner, and exhibit excellent effects of appropriate charging characteristics and charging stability due to environmental fluctuations. These inorganic fine particles can be used singly or in combination of two or more.

  The content of inorganic fine particles in the toner base particles is determined by fluorescent X-ray analysis. A calibration curve is prepared by fluorescent X-ray analysis using toner base particles in which the content of inorganic fine particles is clear in advance, and the content of inorganic fine particles in the toner base particles is obtained by fluorescent X-ray analysis using the calibration curve. . For example, ZSX-100E manufactured by Rigaku Corporation can be used as the fluorescent X-ray apparatus. Further, when two or more kinds of inorganic fine particles were used, the total of the analysis values of the inorganic fine particle content was used as the inorganic fine particle content in the toner base particles.

Further, when the inorganic fine particles are present in a certain amount in the vicinity of the surface of the toner base particles, the effects of the present invention can be better provided, and the toner fluidity is particularly greatly improved. The amount of inorganic fine particles present on the surface of the toner base particles is measured as follows.
For the measurement, XPS (X-ray photoelectron spectroscopy) method is used. Here, it is a region of the extreme surface with a toner surface number of about several nm. The measurement method, type of apparatus, conditions, and the like are not particularly limited as long as similar results can be obtained, but the following conditions are preferable.

Apparatus: 1600S type X-ray photoelectron spectrometer manufactured by PHI X-ray source: MgKα (400 W)
Analysis area: 0.8 × 2.0mm
Pretreatment: The sample was packed in an aluminum dish and measured by adhering to a sample holder with a carbon sheet.
Surface atom concentration calculation: Relative sensitivity factor provided by PHI was used.

The obtained result is atomic% (number of atoms%).
Further, when two or more kinds of inorganic fine particles were used, the total of the element concentrations derived from the inorganic fine particles was used as the calculated analysis value.
According to the analysis result of the above method, the concentration of the element derived from the inorganic fine particles obtained by the XPS method in the toner base particles is 0.1 to 15 atomic% (number of atoms%), more preferably 0.5 to 0.5. It is desirable to be 5 atomic%.

  Specific examples of the inorganic fine particles include, for example, silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, tin oxide, silica sand, clay, mica, wollastonite, Examples thereof include diatomaceous earth, chromium oxide, cerium oxide, pengala, antimony trioxide, magnesium oxide, zirconium oxide, barium sulfate, barium carbonate, calcium carbonate, silicon carbide, and silicon nitride. Among these, in particular, silica and titanium oxide exhibit excellent effects in the present invention, and it is more preferable to use a combination of the two.

  In addition, inorganic fine particles that have been surface-treated with a hydrophobizing agent may be used. As the hydrophobic treatment agent, for example, a silane coupling agent, a silylating agent, a silane coupling agent having a fluorinated alkyl group, an organic titanate coupling agent, an aluminum coupling agent and the like are preferable surface treatment agents. It is done. A sufficient effect can be obtained even when a silicone oil is used as a hydrophobizing agent and subjected to a surface treatment.

[Active hydrogen-containing compounds]
As will be described later, the above-mentioned polyester prepolymer (A) having an isocyanate group is made to have a higher molecular weight by an extension reaction and / or a crosslinking reaction with an active hydrogen compound.

  As the active hydrogen compound used in the present invention, amines (B) are preferably used, and a urea-modified polyester resin (UMPE) can be obtained by reaction with the isocyanate group of the polyester prepolymer (A). This has excellent performance as a toner binder.

  As the amines (B), the diamine (B1), trivalent or higher polyamine (B2), amino alcohol (B3), amino mercaptan (B4), amino acid (B5), and amino groups of B1 to B5 were blocked. (B6) etc. are mentioned. Examples of the diamine (B1) include aromatic diamines (phenylenediamine, diethyltoluenediamine, 4,4′-diaminodiphenylmethane, etc.); alicyclic diamines (4,4′-diamino-3,3′-dimethyldicyclohexylmethane, diamino). Cyclohexane, isophorone diamine, etc.); and aliphatic diamines (ethylene diamine, tetramethylene diamine, hexamethylene diamine, etc.) and the like. Examples of the trivalent or higher polyamine (B2) include diethylenetriamine and triethylenetetramine. Examples of amino alcohol (B3) include ethanolamine and hydroxyethylaniline. Examples of amino mercaptan (B4) include aminoethyl mercaptan and aminopropyl mercaptan. Examples of the amino acid (B5) include aminopropionic acid and aminocaproic acid. Examples of the B1 to B5 amino group blocked (B6) include ketimine compounds and oxazolidine compounds obtained from the amines of B1 to B5 and ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.). Among these amines (B), preferred are B1 and a combination of B1 and a small amount of B2.

  Furthermore, if necessary, the molecular weight of a modified polyester such as a urea-modified polyester can be adjusted using an elongation terminator. Examples of the elongation terminator include monoamines (diethylamine, dibutylamine, butylamine, laurylamine, etc.), and those obtained by blocking them (ketimine compounds).

The use ratio of the amines (B) is equivalent to the isocyanate group [NCO] in the prepolymer (A) having an isocyanate group and the amino group [NHx] (x is 1 or 2) in the amines (B). The ratio [NCO] / [NHx] is usually 1/2 to 2/1, preferably 1.5 / 1 to 1 / 1.5, more preferably 1.2 / 1 to 1 / 1.2. . If the equivalent ratio is too high or too low, the molecular weight of the urea-modified polyester becomes low, and the hot offset resistance of the resulting toner deteriorates.
In the present invention, the polyester modified with a urea bond may contain a urethane bond (—O (CO) NH—) together with a urea bond (—NH (CO) NH—). The molar ratio between the urea bond content and the urethane bond content is usually 100/0 to 10/90, preferably 80/20 to 20/80, and more preferably 60/40 to 30/70. When the molar ratio of the urea bond is less than 10%, the hot offset resistance is deteriorated.

<Properties of toner binder, etc.>
In the present invention, as described above, a urea-modified polyester resin obtained by reaction of the polyester prepolymer (A) and the amines (B) is used as a toner binder, and a non-reactive polyester or the like is used. Other components (including resins used in the preparation of the colorant master batch described later) are also used in combination.

  In the present invention, the glass transition point (Tg) of the toner binder is usually 50 to 70 ° C., preferably 55 to 65 ° C. If Tg is too low, the heat-resistant storage stability of the toner is deteriorated. Conversely, if Tg is too high, the low-temperature fixability becomes insufficient. In the dry toner of the present invention, the use of a urea-modified polyester resin or the like tends to have good heat-resistant storage stability even when the glass transition point is low as compared with known polyester toners. As the storage elastic modulus of the toner binder, the temperature (TG ′) at which the measurement frequency is 20 Hz becomes 1000 Pa is usually 100 ° C. or higher, preferably 110 to 200 ° C. When the TG ′ is too low, the hot offset resistance is deteriorated. As the viscosity of the toner binder, the temperature (Tη) at which the measurement frequency is 20 Hz becomes 100 Pa · s is usually 180 ° C. or less, preferably 90 to 160 ° C. If the Tη is too high, the low-temperature fixability deteriorates. That is, TG ′ is preferably higher than Tη from the viewpoint of achieving both low temperature fixability and hot offset resistance. In other words, the difference between TG ′ and Tη (TG′−Tη) is preferably 0 ° C. or more. More preferably, it is 10 degreeC or more, Most preferably, it is 20 degreeC or more. The upper limit of the difference is not particularly limited. Further, from the viewpoint of achieving both heat-resistant storage stability and low-temperature fixability, the difference between Tη and Tg is preferably 0 to 100 ° C. More preferably, it is 10-90 degreeC, Most preferably, it is 20-80 degreeC.

[Aqueous medium phase]
<Aqueous medium>
In the present invention, the aqueous medium in which the resin fine particles (B) described later are dispersed to form an aqueous medium phase may be water alone, or a solvent miscible with water may be used in combination. Examples of miscible solvents include alcohols (methanol, isopropanol, ethylene glycol, etc.), dimethylformamide, tetrahydrofuran, cellosolves (methyl cellosolve, etc.), lower ketones (acetone, methyl ethyl ketone, etc.), and the like. These can be used singly or in combination of two or more.

  Furthermore, in order to reduce the viscosity when the resin component contained in the organic solvent phase is dispersed in an aqueous medium, a solvent in which the polyester prepolymer (A) is soluble can be used in combination. It is preferable to use the solvent in that the particle size distribution of the toner particles becomes sharp. The solvent is preferably volatile with a boiling point of less than 100 ° C. because it can be easily distilled off. Examples of the solvent include toluene, xylene, benzene, carbon tetrachloride, methylene chloride, 1,2-dichloroethane, 1,1,2-trichloroethane, trichloroethylene, chloroform, monochlorobenzene, dichloroethylidene, methyl acetate, ethyl acetate, Examples thereof include methyl ethyl ketone and methyl isobutyl ketone, and these can be used singly or in combination of two or more. Particularly preferred are aromatic solvents such as toluene and xylene; halogenated hydrocarbons such as methylene chloride, 1,2-dichloroethane, chloroform and carbon tetrachloride; and methyl acetate and ethyl acetate. The usage-amount of the solvent with respect to 100 parts of prepolymers (A) is 0-300 parts normally, Preferably it is 0-100 parts, More preferably, it is 25-70 parts. When the solvent is used, after the urea-modified polyester is formed, it is distilled off by heating under normal pressure or reduced pressure like other organic solvents.

<Resin fine particles (B)>
In the present invention, the resin fine particles (B) used by being dispersed in an aqueous medium are usually 5 to 300 nm, preferably 20 to 200 nm. The resin fine particles (B), unlike the resin fine particles (A), are bonded to the surface or the surface layer portion of the dispersed particles formed by dispersing the organic medium in the aqueous medium phase, thereby forming toner particles. Is a component that functions as an external additive.

  The resin fine particles (B) preferably have a glass transition point (Tg) of 40 to 90 ° C, and more preferably in the range of 50 to 70 ° C. If the Tg is too low, toner storage stability is deteriorated, and blocking occurs during storage and in the developing machine. On the other hand, if it is too high, the resin fine particles (B) inhibit the adhesiveness to the fixing paper, and the minimum fixing temperature rises, so that a sufficient fixing temperature range cannot be secured. Inconveniences such as being unable to be removed or being peeled off when the fixed image is rubbed occur.

  The weight average molecular weight is preferably 200,000 or less, more preferably 50,000 or less. The lower limit is usually 4000. If the weight average molecular weight is too high, the resin fine particles inhibit the adhesion to the fixing paper, and the minimum fixing temperature is increased.

  The resin fine particles (B) may be any resin that can form a dispersion in an aqueous medium, and may be a thermoplastic resin or a thermosetting resin. For example, a vinyl resin, a polyurethane resin, an epoxy resin Examples thereof include resins, polyester resins, polyamide resins, polyimide resins, silicon resins, phenol resins, melamine resins, urea resins, aniline resins, ionomer resins, and polycarbonate resins. These can be used singly or in combination of two or more. Among these, vinyl resins, polyurethane resins, epoxy resins, polyester resins, or combinations thereof are preferable because an aqueous dispersion of fine spherical resin particles is easily obtained. Vinyl resins are polymers obtained by homopolymerization or copolymerization of vinyl monomers, such as styrene- (meth) acrylic acid ester copolymers, styrene-butadiene copolymers, (meth) acrylic acid-acrylic acid ester copolymers. Examples thereof include a polymer, a styrene-acrylonitrile copolymer, a styrene-maleic anhydride copolymer, and a styrene- (meth) acrylic acid copolymer.

  The dispersion / blending amount of the resin fine particles (B) in the aqueous medium is preferably 0.5 to 10% by weight with respect to the organic solvent phase. Moreover, More preferably, it is 1-3 weight%.

  In the preparation of the toner of the present invention, the resin fine particles (B) used in the aqueous medium are used for the purpose of controlling (aligning) the toner shape (circularity, particle size distribution, etc.) and are mainly formed. It is unevenly distributed on the surface of the particle. The surface coverage by the resin fine particles (B) with respect to the toner particles is preferably in the range of 1 to 90%, more preferably in the range of 5 to 80%. If the surface coverage is too high, the toner particle surface is almost completely covered with the resin fine particles (B), and the bleed of the wax (release agent) wax inside the toner particles to the toner particle surface is inhibited. As a result, the releasability effect is not exhibited, and there is a problem that an offset to the fixing roll occurs. Conversely, if the surface coverage is too low, the adhesion between the toner particles tends to work, and the toner tends to aggregate. Therefore, the fluidity of the toner is deteriorated, which is not preferable.

[Other ingredients]
<Colorant>
As the colorant used in the present invention, all known dyes and pigments can be used. For example, carbon black, nigrosine dye, iron black, naphthol yellow S, Hansa yellow (10G, 5G, G), cadmium yellow, yellow Iron oxide, ocher, yellow lead, titanium yellow, polyazo yellow, oil yellow, Hansa yellow (GR, A, RN, R), pigment yellow L, benzidine yellow (G, GR), permanent yellow (NCG), Vulcan fast Yellow (5G, R), Tartrazine Lake, Quinoline Yellow Lake, Anthrazan Yellow BGL, Isoindolinone Yellow, Bengala, Red Tan, Lead Zhu, Cadmium Red, Cadmium Mercury Red, Antimon Zhu, Permanent Red 4R , Para red, phisa red, para Lortho Nitroaniline Red, Resol Fast Scarlet G, Brilliant Fast Scarlet, Brilliant Carnmin BS, Permanent Red (F2R, F4R, FRL, FRLL, F4RH), Fast Scarlet VD, Belkan Fast Rubin B, Brilliant Scarlet G, Resol Rubin GX, Permanent Red F5R, Brilliant Carmine 6B, Pigment Scarlet 3B, Bordeaux 5B, Tolujing Maroon, Permanent Bordeaux F2K, Helio Bordeaux BL, Bordeaux 10B, Bon Maroon Light, Bon Maroon Medium, Eosin Lake, Rhodamine Lake B, Rhodamine Lake Y, Alizarin Lake, Thioindigo Red B, Thioindigo Maroon, Oil Red, Quinacridone Red, Lazolone Red, Polyazo Red, Chrome Vermilion, Benzidine Orange, Perinone Orange, Oil Orange, Cobalt Blue, Cerulean Blue, Alkaline Blue Lake, Peacock Blue Lake, Victoria Blue Lake, Metal Free Phthalocyanine Blue, Phthalocyanine Blue, Fast Sky Blue, Indance Ren Blue (RS, BC), Indigo, Ultramarine Blue, Bituminous Blue, Anthraquinone Blue, Fast Violet B, Methyl Violet Lake, Cobalt Purple, Manganese Purple, Dioxane Violet, Anthraquinone Violet, Chrome Green, Zinc Green, Chrome Oxide, Pyridian, Emerald Green , Pigment Green B, Naphthol Green B, Green Gold, Acid Green Lake, Malachite Grits Enlake, phthalocyanine green, anthraquinone green, titanium oxide, zinc white, litbon and mixtures thereof can be used.

  The amount of the colorant used is usually 1 to 15% by weight, preferably 3 to 10% by weight as the content in the toner base of the present invention.

  The colorant used in the present invention can also be used as a master batch combined with a resin. Examples of the binder resin to be kneaded with the production of the master batch or the master batch include, for example, styrene such as polystyrene, poly p-chlorostyrene, polyvinyltoluene, and its substitutes in addition to the urea-modified polyester resin and non-reactive polyester resin. Polymers of: styrene-p-chlorostyrene copolymer, styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer, styrene-acrylic acid Ethyl copolymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, Styrene-α-Chlor Methyl tacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer, styrene-maleic acid Styrene copolymers such as copolymers and styrene-maleic acid ester copolymers; polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, epoxy resin, epoxy polyol resin, polyurethane Polyamide, polyvinyl butyral, polyacrylic acid resin, rosin, modified rosin, terpene resin, aliphatic or alicyclic hydrocarbon resin, aromatic petroleum resin, chlorinated paraffin, paraffin wax, etc. These can be used singly or in combination of two or more.

  This master batch can be obtained by mixing and kneading a resin for a master batch and a colorant under a high shear force. At this time, an organic solvent can be used in order to enhance the interaction between the colorant and the resin. In addition, a so-called flushing method, which is a wet cake of a colorant, is a method of mixing and kneading an aqueous paste containing water of a colorant together with a resin and an organic solvent, transferring the colorant to the resin side, and removing moisture and organic solvent components. Since it can be used as it is, it does not need to be dried and is preferably used.

For mixing and kneading, a high shearing dispersion device such as a three-roll mill is preferably used.
The colorant or masterbatch can be dissolved or dispersed in the organic solvent phase, but is not limited thereto.

<Release agent>
The toner of the present invention may contain a wax together with a toner binder and a colorant. Known waxes can be used, and examples thereof include polyolefin waxes (polyethylene wax, polypropylene wax, etc.); long chain hydrocarbons (paraffin wax, sazol wax, etc.); carbonyl group-containing waxes, and the like. Of these, carbonyl group-containing waxes are preferred. Examples of the carbonyl group-containing wax include polyhydric alcohol carboxylates (carnauba wax, montan wax, trimethylolpropane tribehenate, pentaerythritol tetrabehenate, pentaerythritol diacetate dibehenate, glycerin tribehenate, 1 , 18-octadecanediol distearate, etc.); polyvalent carboxylic esters (tristearyl trimellitic acid, distearyl maleate, etc.); polyvalent amine carboxylic acid amides (ethylenediamine dibehenyl amide, etc.); polyvalent carboxylic acid amides (tri Meritic acid tristearyl amide, etc.); and dialkyl ketones (distearyl ketone, etc.). Among these carbonyl group-containing waxes, polyhydric alcohol carboxylic acid esters such as pentaerythritol tetrabehenate are preferable. The melting point of the wax used in the present invention is usually 40 to 160 ° C, preferably 50 to 120 ° C, more preferably 60 to 90 ° C. A wax having a melting point that is too low adversely affects heat-resistant storage stability. Conversely, a wax having a melting point that is too high tends to cause a cold offset during fixing at a low temperature. The melt viscosity of the wax is preferably 5 to 1000 mPa · s, more preferably 10 to 100 mPa · s, as a measured value at a temperature 20 ° C. higher than the melting point. The wax having a too high melt viscosity has a poor effect of improving hot offset resistance and low-temperature fixability.

The amount of the wax (release agent) used is usually 0 to 40% by weight, preferably 3 to 30% by weight as the content in the toner base of the present invention.
Further, the wax (release agent) can be dissolved or dispersed in the organic solvent phase, but is not limited thereto.

<Charge control agent>
The toner of the present invention may contain a charge control agent as necessary. Any known charge control agent can be used. For example, nigrosine dye, triphenylmethane dye, chromium-containing metal complex dye, molybdate chelate pigment, rhodamine dye, alkoxy amine, quaternary ammonium salt (fluorine) Modified quaternary ammonium salts), alkylamides, phosphorus simple substances or compounds, tungsten simple substances or compounds, fluorine-based activators, salicylic acid metal salts, metal salts of salicylic acid derivatives, and the like. Specifically, Nitronine-based dye Bontron 03, quaternary ammonium salt Bontron P-51, metal-containing azo dye Bontron S-34, oxynaphthoic acid metal complex E-82, salicylic acid metal complex E- 84, E-89 of phenol-based condensate (above, manufactured by Orient Chemical Industries), TP-302, TP-415 of quaternary ammonium salt molybdenum complex (above, manufactured by Hodogaya Chemical Co., Ltd.), quaternary ammonium Copy charge PSY VP2038 of salt, copy blue PR of triphenylmethane derivative, copy charge NEG VP2036 of quaternary ammonium salt, copy charge NX VP434 (above, manufactured by Hoechst), LRA-901, LR-147 which is a boron complex (Nippon Carlit), copper phthalocyanine, perylene, quinacridone, Zone-based pigment, a sulfonic acid group, a carboxyl group, and polymer compounds having a functional group such as a quaternary ammonium salt.

  In the present invention, the amount of charge control agent used is determined by the toner production method including the type of binder resin, the presence or absence of additives used as necessary, and the dispersion method, and is uniquely limited. However, it is preferably used in the range of 0.1 to 10 parts by weight with respect to 100 parts by weight of the binder resin. The range of 0.2 to 5 parts by weight is preferable. When the amount exceeds 10 parts by weight, the chargeability of the toner is too high, the effect of the main charge control agent is reduced, the electrostatic attractive force with the developing roller is increased, the flowability of the developer is reduced, and the image density is reduced. Incurs a decline. These charge control agents can be dissolved and dispersed after being melt-kneaded with a masterbatch or resin, and of course, they may be added when dissolved or dispersed directly in an organic solvent. It is preferable to make it.

[Preparation of toner particles]
Toner particles (base material) can be prepared by the following method.
<Dispersion and reaction of organic solvent phase>
As described above, in the toner particles, the organic solvent phase containing the polyester prepolymer (A) is dispersed in the aqueous medium phase together with the amines (B), and an elongation reaction and / or a crosslinking reaction is performed in the aqueous medium phase. To form a urea-modified polyester.

  The polyester prepolymer (A), the non-reactive polyester, the resin fine particles (A), and the inorganic fine particles together with the colorant or the colorant master batch, the release agent, and the charge control agent are previously dissolved or dispersed in the organic solvent phase. The colorant or the colorant masterbatch, the release agent and the charge control agent may be mixed when dispersed in the organic solvent phase in the aqueous medium. In the present invention, the colorant or the colorant master batch and the charge control agent may be added and blended after the toner particles are formed. For example, the charge control agent is preferably driven after the toner particles are formed, and after the toner particles not containing the colorant are formed, the colorant can be added by a known dyeing method.

  Mixing of the polyester prepolymer (A) in the organic solvent phase and the amines (B) (especially blocked ketimine) may be performed before dispersion in the aqueous medium. When a blocked ketimine or the like is used as the amine (B), the block is removed in the aqueous medium, and the elongation and / or crosslinking reaction with the polyester prepolymer (A) can be performed. Further, the amine (B) may be added after the organic solvent phase is dispersed in the aqueous medium. When the amines (B) are added after the dispersion of the organic solvent phase, the reaction starts from the dispersed particle interface, urea-modified polyester is preferentially generated from the surface of the toner particles to be prepared, and a concentration gradient may be provided inside the particles. it can.

  Examples of a method for stably forming a dispersion of an organic solvent phase and an amine (B) in an aqueous medium include a method in which a shearing force is applied and dispersed.

  The dispersion method is not particularly limited, and known methods such as a low-speed shear method, a high-speed shear method, a friction method, a high-pressure jet method, and an ultrasonic wave can be applied. The particle size of the dispersion is preferably 2 to 20 μm, and for this purpose, it is preferable to use a high-speed shearing method. When a high-speed shearing disperser is used, the number of rotations is not particularly limited, but is usually 1000 to 30,000 rpm, preferably 5000 to 20,000 rpm. The dispersion time depends on the processing amount and is not particularly limited. However, in the case of a batch method, it is usually about 0.1 to 5 minutes. The temperature during dispersion is usually 0 to 150 ° C. (under pressure), preferably 40 to 98 ° C. It is preferable that the temperature during dispersion is high because the viscosity of the polyester prepolymer (A) and the like contained in the organic solvent dispersed phase can be lowered and the dispersion is easy.

  The amount of the aqueous medium (excluding the resin fine particles (B)) used relative to 100 parts of the solid content contained in the organic solvent phase is usually 50 to 2000 parts by weight, preferably 100 to 1000 parts by weight. If the amount used is too small, the dispersed state of the organic solvent phase becomes non-uniform, and toner particles having a predetermined particle diameter cannot be obtained. On the other hand, if it is too much, it is not economical because it is not particularly effective and disadvantageous in terms of cost. Moreover, a dispersing agent can also be used as needed. It is preferable to use a dispersant because the particle size distribution becomes sharp and the dispersion is stable.

  When the dispersant is used, examples of the dispersant include anionic surfactants such as alkylbenzene sulfonates, α-olefin sulfonates, and phosphate esters; alkylamine salts, amino alcohol fatty acid derivatives, polyamine fatty acid derivatives, Cationic surfactants of amine salt type such as imidazoline, and quaternary ammonium salt type such as alkyltrimethylammonium salt, dialkyldimethylammonium salt, alkyldimethylbenzylammonium salt, pyridinium salt, alkylisoquinolinium salt, benzethonium chloride Nonionic surfactants such as fatty acid amide derivatives and polyhydric alcohol derivatives; amphoteric boundaries such as alanine, dodecyldi (aminoethyl) glycine, di (octylaminoethyl) glycine and N-alkyl-N, N-dimethylammonium betaine Active agents.

  Further, by using a surfactant having a fluoroalkyl group, a dispersion effect can be exhibited with a very small amount of use. Preferred examples of the anionic surfactant having a fluoroalkyl group include a fluoroalkylcarboxylic acid having 2 to 10 carbon atoms and a metal salt thereof, disodium perfluorooctanesulfonylglutamate, 3- [ω-fluoroalkyl ( C6-C11) oxy] -1-alkyl (C3-C4) sodium sulfonate, 3- [ω-fluoroalkanoyl (C6-C8) -N-ethylamino] -1-propanesulfonic acid sodium, fluoroalkyl (C11- C20) Carboxylic acid and its metal salt, Perfluoroalkylcarboxylic acid (C7 to C13) and its metal salt, Perfluoroalkyl (C4 to C12) sulfonic acid and its metal salt, Perfluorooctanesulfonic acid diethanolamide, N-propyl -N- (2hydroxy Ciethyl) perfluorooctanesulfonamide, perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salt, perfluoroalkyl (C6-C10) -N-ethylsulfonylglycine salt, monoperfluoroalkyl (C6-C16) ethyl phosphoric acid Examples include esters. As a trade name, Surflon S-111, S-112, S-113 (Asahi Glass Co., Ltd.); Florard FC-93, FC-95, FC-98, FC-129 (Sumitomo 3M Co., Ltd.); Unidyne DS-101 DS-102 (manufactured by Taikin Kogyo Co., Ltd.); Megafac F-l10, F-120, F-113, F-191, F-812, F-833 (Dainippon Ink Co., Ltd.); Xtop EF- 102, 103, 104, 105, 112, 123A, 123B, 306A, 501, 201, 204 (manufactured by Tochem Products); and Fagents F-100, F150 (manufactured by Neos).

  Further, as the cationic surfactant, aliphatic quaternary ammonium such as aliphatic primary amine, secondary amine or secondary amine acid having a fluoroalkyl group, perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salt, etc. Salts, benzalkonium salts, benzethonium chloride, pyridinium salts, imidazolinium salts, and the like. Trade names include Surflon S-121 (Asahi Glass Co., Ltd.), Florard FC-135 (Sumitomo 3M Co., Ltd.); Unidyne DS-202 (Daikin Industries Co., Ltd.); MegaFuck F-150, F-824 (Dainippon Ink) Xetop EF-132 (manufactured by Tochem Products); Footage F-300 (manufactured by Neos) and the like.

  Further, calcium phosphate, calcium carbonate, titanium oxide, colloidal silica, hydroxyapatite and the like can also be used as inorganic compound-based dispersants that are hardly soluble in water.

  Further, the dispersed droplets may be stabilized using a polymer protective colloid. For example, acids such as acrylic acid, methacrylic acid, α-cyanoacrylic acid, α-cyanomethacrylic acid, itaconic acid, crotonic acid, fumaric acid, maleic acid or maleic anhydride; (meth) acrylic monomer containing hydroxyl group Bodies such as β-hydroxyethyl acrylate, β-hydroxyethyl methacrylate, β-hydroxypropyl acrylate, β-hydroxypropyl methacrylate, γ-hydroxypropyl acrylate, γ-hydroxypropyl methacrylate, acrylic acid 3 -Chloro-2-hydroxypropyl, 3-chloro-2-hydroxypropyl methacrylate, diethylene glycol monoacrylate, diethylene glycol monomethacrylate, glycerol monoacrylate, glycerol monomethacrylate, N-methyl Roll acrylamide, N-methylol methacrylamide, etc .; Vinyl alcohol or ethers with vinyl alcohol, such as vinyl methyl ether, vinyl ethyl ether, vinyl propyl ether, etc .; Esters of compounds containing vinyl alcohol and carboxyl groups, such as, for example, Pinyl acetate, vinyl propionate, vinyl butyrate, etc .; acrylamide, methacrylamide, diacetone acrylamide or methylol compounds thereof; acid chlorides such as acrylic acid chloride, methacrylic acid chloride; pinylviridine, vinylpyrrolidone, vinylimidazole, ethyleneimine Homopolymers or copolymers of vinyl monomers such as those having a nitrogen atom such as the above or a heterocyclic ring thereof can be used. Also, polyoxyethylene, polyoxypropylene, polyoxyethylene alkylamine, polyoxypropylene alkylamine, polyoxyethylene alkylamide, polyoxypropylene alkylamide, polyoxyethylene nonyl phenyl ether, polyoxyethylene lauryl phenyl ether, polyoxy Polyoxyethylenes such as ethylene stearyl phenyl ester and polyoxyethylene nonylphenyl ester; celluloses such as methyl cellulose, hydroxyethyl cellulose, and hydroxypropyl cellulose can also be used.

  When using a dispersion stabilizer that is soluble in an acid or alkali such as calcium phosphate, remove the calcium phosphate from the fine particles by dissolving the calcium phosphate with an acid such as hydrochloric acid and then washing with water. To do. In addition, it can be removed by an operation such as enzymatic degradation.

  When a dispersant is used, the dispersant can remain on the surface of the toner particles, but the elongation and / or crosslinking reaction between the polyester prepolymer (A) and the amines (B) is completed. Thereafter, removal by washing or the like is preferable from the viewpoint of the charging characteristics of the toner of the present invention.

  The time required for the elongation and / or cross-linking reaction between the polyester prepolymer (A) and the amines (B) in the dispersed particles of the organic solvent phase dispersed in the aqueous medium depends on the isocyanate group of the polyester prepolymer (A). Although depending on the reactivity with the amines (B), it is usually 10 minutes to 40 hours, preferably about 2 to 24 hours. Moreover, reaction temperature is 0-150 degreeC normally, Preferably it is 40-98 degreeC. Furthermore, a known catalyst can be used for the above reaction as needed, and specific examples include dibutyltin laurate and dioctyltin laurate.

<Shaping process / Toner particle molding>
In order to obtain a desired toner particle shape, a high-viscosity aqueous solution in which a thickener, an activator, or the like is added to the dispersion containing the urea-modified polyester after the elongation and / or crosslinking reaction is further mixed. By using a device that applies a shearing force such as a homomixer or Ebara milder to the mixed dispersion, the dispersed particles can be deformed by utilizing the viscosity difference between the oil phase and the aqueous phase. The conditions at this time include a method for adjusting the shearing force of the apparatus, for example, a method for adjusting the treatment time or the number of treatments, or a viscosity difference between the oil phase and the water phase (for example, a water-insoluble organic solvent in the oil phase). Can be controlled by optimizing the concentration, temperature, thickener, activator and temperature in the aqueous phase.

  In order to remove the organic solvent from the obtained dispersion liquid, a method of gradually elevating the temperature of the entire system and completely evaporating and removing the organic solvent in the droplets can be employed. Alternatively, the dispersion liquid can be sprayed into a dry atmosphere to completely remove the water-insoluble organic solvent in the droplets to form toner particles, and the aqueous dispersant can be removed by evaporation together. As the dry atmosphere, a gas obtained by heating air, nitrogen, carbon dioxide gas, combustion gas, or the like, particularly various air streams heated to a temperature equal to or higher than the boiling point of the highest boiling solvent used is generally used. Sufficient target quality can be obtained by short-time treatment using a spray dryer, belt dryer, rotary kiln or the like.

  When the toner particle has a wide particle size distribution and washing and drying are performed while maintaining the particle size distribution, the particle size distribution can be adjusted by classification into a desired particle size distribution. The classification operation can be performed by removing fine particle portions in a liquid by a cyclone, a decanter, centrifugation, or the like. The classification operation may be performed after the toner particles are obtained as a powder after washing and drying, but it is preferably performed in a liquid in terms of efficiency. Fine particles or coarse particles outside the desired particle size range separated by the classification treatment can be returned to the kneading step and used for forming particles. At that time, fine particles or coarse particles may be in a wet state.

  The dispersant used is preferably removed from the obtained dispersion as much as possible, but it is preferable to carry out it simultaneously with the classification operation described above. By mixing the resulting dried toner particle powder with dissimilar particles such as release agent fine particles, charge control fine particles, fluidizing agent fine particles, and colorant fine particles, or by giving mechanical impact force to the mixed powder By immobilizing and fusing on the surface, it is possible to prevent detachment of the foreign particles from the surface of the resulting composite particle.

  Specific means include a method of applying an impact force to the mixture by blades rotating at high speed, a method of injecting and accelerating the mixture in a high-speed air stream, and causing particles or composite particles to collide with an appropriate collision plate, etc. is there. As equipment, Ong mill (manufactured by Hosokawa Micron Co., Ltd.), I-type mill (manufactured by Nippon Pneumatic Co., Ltd.) is modified to reduce the grinding air pressure, hybridization system (manufactured by Nara Machinery Co., Ltd.), kryptron system (Manufactured by Kawasaki Heavy Industries, Ltd.), automatic mortar and the like.

[Application of external additives]
The toner particles (base material) obtained by the operations and processes as described above are further treated on the surface with an external additive to obtain the toner of the present invention with improved fluidity, developability, chargeability and the like. . As the external additive for assisting, inorganic fine particles can be preferably used. The primary particle diameter of the inorganic fine particles is preferably 5 nm to 2 μm, and particularly preferably 5 nm to 500 nm. Moreover, it is preferable that the specific surface area by BET method is 20-500 m < ² > / g. The proportion of the inorganic fine particles used is preferably 0.01 to 5% by weight, particularly 0.01 to 2.0% by weight, based on the toner particles.

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

  Other than inorganic fine particles, polymer fine particles such as polystyrene, methacrylic ester-based or acrylate-based copolymers obtained by soap-free emulsion polymerization suspension polymerization or dispersion polymerization, silicone resins, benzoguanamine resins, polyamides Polymer particles such as a polycondensation system such as a thermosetting resin can be used.

  The external additive used for improving fluidization and the like is subjected to surface treatment in advance to make it hydrophobic, thereby preventing deterioration of the toner flow characteristics and charging characteristics even under high humidity. be able to. Examples of the surface treatment agent include silane coupling agents, silylating agents, silane coupling agents having a fluorinated alkyl group, organic titanate coupling agents, aluminum coupling agents, silicone oils, and modified silicone oils. Etc. are preferably exemplified.

  Further, for the purpose of improving the cleaning property when removing the developer after transfer remaining on the photosensitive member and the primary transfer medium, toner particles (base material) are made of, for example, zinc stearate, calcium stearate, stearic acid, etc. Fatty acid metal salt; for example, it can be treated with polymer fine particles produced by soap-free emulsion polymerization such as polymethyl methacrylate fine particles and polystyrene fine particles. The polymer fine particles used preferably have a relatively narrow particle size distribution and a volume average particle size of 0.01 to 1 μm.

[Toner shape, etc.]
<Circularity and circularity distribution>
The toner in the present invention preferably has a specific shape and shape distribution, and preferably has an average circularity of 0.950 to 0.990, and an average circularity of 0.960 to 0.985. More preferably, the degree is less than 0.94. A substantially spherical toner within the range of the average circularity is effective for forming a high-definition image having a reproducibility with an appropriate density. The toner having an irregular shape whose average circularity is too low and far from the spherical shape does not satisfy the transferability, and a high-quality image free from dust cannot be obtained. On the other hand, if the average circularity is too high and is closer to a sphere, in a system employing blade cleaning or the like, a cleaning failure occurs on the photosensitive member or the transfer belt and the image Cause dirt. For example, development or transfer with a low image area ratio results in a small amount of residual toner and poor cleaning is not a problem. However, when the image area ratio is high, such as a color photographic image, it is further The toner on which the transferred image is formed may be generated as a transfer residual toner on the photosensitive member, and if this is accumulated, the background stain of the image occurs. In addition, there is a problem that the charging roller or the like that contacts and charges the photosensitive member is contaminated, and the original charging ability is not exhibited.

  The measurement of the circularity is suitably performed by an optical method in which a suspension containing particles is passed through an imaging unit detection zone on a flat plate, and a particle image is optically detected and analyzed by a CCD camera. With this technique, the circularity is defined as a value obtained by dividing the circumference of an equivalent circle equal to the projected area of the particle by the circumference of the particle (projected image). The average circularity value can be automatically measured by a flow type particle image analyzer FPIA-2100 (manufactured by Toa Medical Electronics Co., Ltd.). A specific measurement method will be described later.

<Volume average particle diameter / number average particle diameter>
The toner of the present invention preferably has a volume average particle diameter (Dv) of 2 to 7 μm, more preferably 3 to 7 μm. The ratio [Dv / Dn] to the number average particle diameter (Dn) is preferably 1.25 or less, more preferably 1.10 to 1.25, and particularly 1.10 to 1.20. It is preferable to be within the range. Here, the volume average particle diameter is defined as Dv = [(Σ (nD ³ ) / Σn] ^1/3 (where n is the number of particles and D is the particle diameter).

  By setting the volume average particle diameter (Dv) and the ratio [Dv / Dn] of the toner of the present invention within the above ranges, the toner is excellent in heat-resistant storage, low-temperature fixability, and hot offset resistance. When used in a full-color copying machine, etc., it has excellent image glossiness. Furthermore, in a two-component developer, even if the toner balance for a long time is performed, the fluctuation of the toner particle diameter in the developer is reduced, and the developing device Good and stable developability can be obtained even with long-term stirring. Even when used as a one-component developer, even if the balance of the toner is performed, the fluctuation of the toner particle diameter is reduced, and the toner filming on the developing roller and the toner layer are made thin. The toner is not fused to a member such as a blade, and good and stable developability and an image can be obtained even during long-term use (stirring) of the developing device.

  In general, it is said that the smaller the toner particle size, the more advantageous it is to obtain a high-resolution and high-quality image, but it is disadvantageous in terms of transferability and cleaning properties. . If the volume average particle diameter of the toner is too small, the two-component developer causes the toner to be fused to the surface of the carrier during long-term agitation in the developing device, reducing the charging ability of the carrier, or being used as a one-component developer. In such a case, filming of the toner on the developing roller and fusion of the toner to a member such as a blade for thinning the toner are likely to occur. Further, these phenomena are the same for the toner having a fine powder content larger than the range of the present invention.

  Conversely, when the toner particle size is large, it becomes difficult to obtain a high-resolution and high-quality image, and the toner particle size fluctuates greatly when the balance of the toner in the developer is performed. There are many cases. It was also clarified that the same applies when the volume average particle diameter / number average particle diameter [Dv / Dn] is too large. In addition, if [Dv / Dn] is too small, there are preferable aspects from the viewpoint of stabilizing the behavior of the toner and uniformizing the charge amount, but there are cases where the toner is insufficiently charged and cleaning is also performed. It became clear that it might worsen sex.

  The volume average particle diameter (Dv) and the ratio [Dv / Dn] of the volume average particle diameter (Dv) to the number average particle diameter (Dn) are measured by COULTER TA-II (manufactured by COULTER ELECTRONICS, INC), etc. Is automatically measured. The aperture diameter is 100 μm.

[Two-component developer]
When the toner of the present invention is used for a two-component developer, it may be used by mixing with a magnetic carrier, and the content ratio of the carrier and the toner in the developer is 1 to 10 weights of toner with respect to 100 parts by weight of the carrier. Part is preferable, and the range of 5 to 10 parts by weight is more preferable.

  As the magnetic carrier, conventionally known ones such as iron powder, ferrite powder, magnetite powder, magnetic resin carrier having a particle diameter of about 20 to 200 μm can be used. Examples of the coating material for the magnetic carrier include amino resins such as urea-formaldehyde resin, melamine resin, benzoguanamine resin; urea resin, polyamide resin, and epoxy resin. Polyvinyl and polyvinylidene resins such as acrylic resins, polymethyl methacrylate resins, polyacrylonitrile resins, polyvinyl acetate resins, polyvinyl alcohol resins, polyvinyl butyral resins; polystyrene resins such as polystyrene resins and styrene acrylic copolymer resins; Halogenated olefin resins such as vinyl chloride; polyester resins such as polyethylene terephthalate resin and polybutylene terephthalate resin: polycarbonate resin, polyethylene resin, polyvinyl fluoride resin, polyvinylidene fluoride resin, polytrifluoroethylene resin, polyhexa Fluoropropylene resin, copolymer of vinylidene fluoride and acrylic monomer, copolymer of vinylidene fluoride and vinyl fluoride, tetrafluoroethylene and vinylidene fluoride Fluoro such as terpolymers of emission and non-fluoride monomers including, and silicone resins.

Moreover, you may make conductive powder etc. contain in coating resin as needed. As the conductive powder, metal powder, carbon black, titanium oxide, tin oxide, zinc oxide or the like can be used. These conductive powders preferably have an average particle diameter of 1 μm or less. When the average particle diameter is larger than 1 μm, it becomes difficult to control electric resistance.
The toner of the present invention can also be used as a one-component magnetic toner that does not use a carrier, or a non-magnetic toner.

[Image forming apparatus]
Hereinafter, an image forming apparatus using the electrophotographic toner of the present invention or a two-component developer composed of the toner and a carrier will be described.

<Intermediate transfer member>
An embodiment of an intermediate transfer member of a transfer system in the present invention will be described. FIG. 1 is a schematic configuration diagram of a copying machine according to the present embodiment. Around a photosensitive drum (hereinafter referred to as a photosensitive member) 10 as an image carrier, a charging roller 20 as a charging device, an exposure device 30, a cleaning device 60 having a cleaning blade, a static elimination lamp 70 as a static elimination device, and development. An apparatus 40 and an intermediate transfer member 50 as an intermediate transfer member are provided. The intermediate transfer member 50 is suspended by a plurality of suspension rollers 51 and is configured to run endlessly in the direction of the arrow by a driving unit such as a motor (not shown). A part of the suspension roller 51 also serves as a transfer bias roller for supplying a transfer bias to the intermediate transfer member, and a predetermined transfer bias voltage is applied from a power source (not shown). A cleaning device 90 having a cleaning blade for the intermediate transfer member 50 is also provided. Further, a transfer roller 80 is provided as a transfer means for transferring the developed image onto the transfer paper 100 as the final transfer material, facing the intermediate transfer member 50, and the transfer roller 80 is transferred by a power supply device (not shown). Supplied. Around the intermediate transfer member 50, a corona charger 52 as a charge applying unit is provided.

  The developing device 40 includes a developing belt 41 as a developer carrier, a black (hereinafter referred to as “Bk”) developing unit 45K, a yellow (hereinafter referred to as “Y”) developing unit 45Y, The developing unit 45M is hereinafter referred to as magenta and the cyan (hereinafter referred to as C) developing unit 45C. Further, the developing belt 41 is stretched between a plurality of belt rollers, and is configured to run endlessly in a direction indicated by an arrow by a driving unit such as a motor (not shown). Moves at approximately the same speed as 10.

  Since the structure of each developing unit is common, the following description will be given only for the Bk developing unit 45K, and the other developing units 45Y, 45M, and 45C will be described in the parts corresponding to those in the Bk developing unit 45K in the drawing. Y, M, and C are added after the numbers given to the units, and the description is omitted. The developing unit 45K is disposed so as to immerse the developing tank 42K containing a high-viscosity, high-concentration liquid developer containing toner particles and a carrier liquid component, and the lower part in the liquid developer in the developing tank 42K. And a coating roller 44K for thinning the developer pumped from the pumping roller 43K and applying it to the developing belt 41. The application roller 44K has conductivity, and a predetermined bias is applied from a power source (not shown).

  In addition to the apparatus configuration as shown in FIG. 1, the apparatus configuration of the copying machine according to the present embodiment is an apparatus configuration in which development units 45 for each color are provided around the photoconductor 10 as shown in FIG. It may be.

  Next, the operation of the copying machine according to the present embodiment will be described. In FIG. 1, the photosensitive member 10 is uniformly charged by the charging roller 20 while being driven to rotate in the direction of the arrow, and then the reflected light from the original is imaged and projected by an optical system (not shown) by the exposure device 30 on the photosensitive member 10. An electrostatic charge image is formed on the surface. This electrostatic charge image is developed by the developing device 40 to form a toner image as a visible image. The developer thin layer on the developing belt 41 is peeled off from the belt 41 in a thin layer state by contact with the photosensitive member in the developing region, and moves to a portion where a latent image is formed on the photosensitive member 10. The toner image developed by the developing device 40 is transferred to the surface of the intermediate transfer member 50 at the contact portion (primary transfer region) between the photosensitive member 10 and the intermediate transfer member 50 moving at a constant speed (primary transfer). Transcription). When transferring three or four colors to be superimposed, this process is repeated for each color to form a color image on the intermediate transfer member 50.

  The corona charger 52 for applying an electric charge to the superimposed toner image on the intermediate transfer member is provided at a contact facing portion between the photosensitive member 10 and the intermediate transfer member 50 in the rotation direction of the intermediate transfer member 50. It is installed on the downstream side and on the upstream side of the contact facing portion between the intermediate transfer member 50 and the transfer paper 100. The corona charger 52 gives the toner image a true charge having the same polarity as the charge polarity of the toner particles forming the toner image, and is sufficient for good transfer to the transfer paper 100. Charge is applied to the toner image. The toner image is charged by the corona charger 52 and then transferred to the transfer paper 100 conveyed in the direction of the arrow from a paper supply unit (not shown) by a transfer bias from the transfer roller 80 (two). Next transfer). Thereafter, the transfer paper 100 onto which the toner image has been transferred is separated from the photoconductor 10 by a separation device (not shown), and after a fixing process is performed by a fixing device (not shown), the transfer paper 100 is discharged from the device. On the other hand, after the transfer, the untransferred toner is collected and removed by the cleaning device 60, and the residual charge is discharged by the discharging lamp 70 in preparation for the next charging.

As described above, the static friction coefficient of the intermediate transfer member is preferably 0.1 to 0.6, and more preferably 0.3 to 0.5. The volume resistance of the intermediate transfer member is preferably from several Ωcm to 10 ³ Ωcm. By setting the volume resistance to several Ωcm or more and 10 ³ Ωcm or less, the intermediate transfer member itself is prevented from being charged, and the charge imparted by the charge imparting means is less likely to remain on the intermediate transfer member. Transfer unevenness can be prevented. Further, it is possible to easily apply a transfer bias at the time of secondary transfer.

  The material of the intermediate transfer member is not particularly limited, and all known materials can be used. An example is shown below. (1) A material having a high Young's modulus (tensile modulus) is used as a single-layer belt. PC (polycarbonate), PVDF (polyvinylidene fluoride), PAT (polyalkylene terephthalate), PC (polycarbonate) / PAT ( Polyalkylene terephthalate) blend materials, ETFE (ethylene tetrafluoroethylene copolymer) / PC, ETFE / PAT, PC / PAT blend materials, carbon black dispersed thermosetting polyimide, and the like. These single-layer belts having a high Young's modulus have the advantage that the amount of deformation with respect to stress during image formation is small, and registration is not likely to occur particularly during color image formation. (2) A belt having a two- or three-layer structure in which a belt having a high Young's modulus is used as a base layer and a surface layer or an intermediate layer is provided on the outer periphery thereof. Therefore, the line image has a performance capable of preventing the line image from being lost. (3) Belts having a relatively low Young's modulus using rubber and elastomer, and these belts have an advantage that line images are hardly lost due to their softness. In addition, the width of the belt is made larger than that of the drive roll and the tension roll, and the elasticity of the belt ear protruding from the roll is used to prevent meandering, so that a low cost can be realized without the need for ribs or meandering prevention devices. .

  Conventionally, a fluorine-based resin, a polycarbonate resin, a polyimide resin, or the like has been used for the intermediate transfer belt, but in recent years, an elastic belt in which the entire belt layer or a part of the belt is used as an elastic member has been used. The transfer of a color image using a resin belt has the following problems.

  A color image is usually formed with four colored toners. On one color image, toner layers of 1 to 4 layers are formed. The toner layer receives pressure by passing through the primary transfer (transfer from the photoreceptor to the intermediate transfer belt) and the secondary transfer (transfer from the intermediate transfer belt to the sheet), and the cohesive force between the toners increases. When the cohesive force between the toners increases, the phenomenon of missing characters in the characters and missing edges in the solid portion image tends to occur. Since the resin belt has a high hardness and does not deform according to the toner layer, the toner layer is easily compressed, and the character dropout phenomenon is likely to occur.

  Recently, there is an increasing demand for forming full-color images on various papers, for example, Japanese paper, intentionally irregularities, and forming images on paper. However, a paper with poor smoothness is liable to generate toner and voids at the time of transfer, and transfer loss is likely to occur. When the transfer pressure at the secondary transfer portion is increased to improve the adhesion, the condensing power of the toner layer is increased, and the above-described character void is generated.

  The elastic belt is used for the following purposes. The elastic belt is deformed corresponding to the toner layer and the paper having poor smoothness at the transfer portion. In other words, since the elastic belt deforms following local irregularities, it is possible to obtain a good adhesion without excessively increasing the transfer pressure with respect to the toner layer, and a paper with poor flatness that has no void in characters. In contrast, a transfer image with excellent uniformity can be obtained.

  The elastic belt resin is polycarbonate, fluororesin (ETFE, PVDF), polystyrene, chloropolystyrene, poly-α-methylstyrene, styrene-butadiene copolymer, styrene-vinyl chloride copolymer, styrene-vinyl acetate copolymer. Styrene-maleic acid copolymer, styrene-acrylic acid ester copolymer (for example, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-butyl acrylate copolymer, styrene- Octyl acrylate copolymer and styrene-phenyl acrylate copolymer), styrene-methacrylic acid ester copolymer (for example, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-methacrylic acid). Acid phenyl copolymer, etc.), styrene -Styrenic resins (monopolymer or copolymer containing styrene or styrene-substituted product) such as methyl α-chloroacrylate copolymer, styrene-acrylonitrile-acrylic acid ester copolymer, methyl methacrylate resin, methacrylic acid Butyl resin, ethyl acrylate resin, butyl acrylate resin, modified acrylic resin (for example, silicone-modified acrylic resin, vinyl chloride resin-modified acrylic resin, acrylic / urethane resin, etc.), vinyl chloride resin, styrene-vinyl acetate copolymer, Vinyl chloride-vinyl acetate copolymer, rosin-modified maleic resin, phenol resin, epoxy resin, polyester resin, polyester polyurethane resin, polyethylene, polypropylene, polybutadiene, polyvinylidene chloride, ionomer resin, polyurethane resin, silica One or a combination of two or more selected from the group consisting of carbon resins, ketone resins, ethylene-ethyl acrylate copolymers, xylene resins and polyvinyl butyral resins, polyamide resins and modified polyphenylene oxide resins can be used. . However, it is a matter of course that the material is not limited to the above materials.

  Elastic rubber and elastomer include butyl rubber, fluorine rubber, acrylic rubber, EPDM, NBR, acrylonitrile-butadiene-styrene rubber natural rubber, isoprene rubber, styrene-butadiene rubber, butadiene rubber, ethylene-propylene rubber, ethylene-propylene ter Polymer, chloroprene rubber, chlorosulfonated polyethylene, chlorinated polyethylene, urethane rubber, syndiotactic 1,2-polybutadiene, epichlorohydrin rubber, ricone rubber, fluororubber, polysulfide rubber, polynorbornene rubber, hydrogenated nitrile rubber , Selected from the group consisting of thermoplastic elastomers (for example, polystyrene, polyolefin, polyvinyl chloride, polyurethane, polyamide, polyurea, polyester, fluororesin) It is possible to use one kind or two or more kinds of combinations that. However, it is a matter of course that the material is not limited to the above materials.

  There are no particular restrictions on the conductive agent for adjusting the resistance value. For example, carbon black, graphite, metal powder such as aluminum and nickel, tin oxide, titanium oxide, antimony oxide, indium oxide, potassium titanate, antimony oxide-tin oxide composite Conductive metal oxides such as oxide (ATO) and indium oxide-tin oxide composite oxide (ITO) can be used. The conductive metal oxide may be coated with insulating fine particles such as barium sulfate, magnesium silicate, and calcium carbonate. Of course, the conductive agent is not limited thereto.

  The surface layer material is required to prevent contamination of the photosensitive member by the elastic material and to reduce the surface friction resistance to the transfer belt surface to reduce the adhesion force of the toner to improve the cleaning property and the secondary transfer property. . For example, materials that use one or a combination of two or more of polyurethane, polyester, epoxy resin, etc. to reduce surface energy and increase lubricity, such as fluorine resin, fluorine compound, fluorocarbon, titanium dioxide, silicon carbide, etc. These powders and particles can be used by dispersing one type, two or more types, or a combination of particles having different particle sizes. Further, it is also possible to use a material having a reduced surface energy by forming a fluorine-rich layer on the surface by heat treatment, such as a fluorine-based rubber material.

  The belt manufacturing method is not limited. For example, a centrifugal molding method in which a material is poured into a rotating cylindrical mold to form a belt, a spray coating method in which a liquid paint is sprayed to form a film, and a cylindrical mold are used. Examples include, but are not limited to, a dipping method in which the material is dipped in a solution of the material, a casting method in which it is injected into the inner mold and the outer mold, a method in which a compound is wound around a cylindrical mold and vulcanized and polished. In general, a belt is manufactured by combining a plurality of manufacturing methods.

  As a method for preventing elongation as an elastic belt, there are a method of forming a rubber layer in a core resin layer with little elongation, a method of putting a material for preventing elongation in a core layer, and the like, but the method is limited to a specific manufacturing method is not.

  Materials constituting the core layer for preventing elongation include, for example, natural fibers such as cotton and silk; polyester fibers, nylon fibers, acrylic fibers, polyolefin fibers, polyvinyl alcohol fibers, polyvinyl chloride fibers, polyvinylidene chloride fibers, One or two selected from the group consisting of synthetic fibers such as polyurethane fibers, polyacetal fibers, polyfluoroethylene fibers, and phenol fibers; inorganic fibers such as carbon fibers, glass fibers, and boron fibers; and metal fibers such as iron fibers and copper fibers A combination of two or more species is used to form a woven fabric or a yarn. Of course, the material is not limited to the above.

  The yarn may be twisted in any manner, such as one or a plurality of filaments twisted, a single twisted yarn, various twisted yarns, a double yarn or the like. Further, for example, fibers of a material selected from the above material group may be blended. Of course, the yarn can be used after being subjected to an appropriate conductive treatment. On the other hand, the woven fabric can be any woven fabric such as knitted fabric, and of course, a woven fabric that is interwoven can also be used, and naturally conductive treatment can be applied.

  The production method for providing the core layer is not particularly limited. For example, a method of providing a coating layer on a woven fabric woven in a cylindrical shape on a mold or the like, and a liquid woven woven fabric in a cylindrical shape. Examples thereof include a method in which a coating layer is provided on one or both sides of the core layer by dipping in rubber or the like, and a method in which a yarn is spirally wound around a mold or the like at an arbitrary pitch and a coating layer is provided thereon.

  The thickness of the elastic layer depends on the hardness of the elastic layer, but if it is too thick, the surface expands and contracts and cracks are likely to occur in the surface layer. Also, it is not preferable that the thickness is too large (approximately 1 mm or more) because the amount of expansion and contraction becomes large and the image is stretched.

<Charging device>
FIG. 7 shows a schematic configuration of an example of an image forming apparatus using a contact-type charging device. A photosensitive member as an object to be charged and an image carrier is rotationally driven in the direction of an arrow at a predetermined speed (process speed). The charging roller, which is a charging member brought into contact with the photosensitive drum, is basically composed of a cored bar and a conductive rubber layer formed on the roller concentrically with the outer periphery of the cored bar. In addition, the charging roller is pressed against the photosensitive drum with a predetermined pressure by a pressurizing unit (not shown). In this case, the charging roller rotates following the rotation of the photosensitive drum. . The charging roller is formed to have a diameter of 16 mm by coating a medium resistance rubber layer of about 100,000 Ω · cm on a core metal having a diameter of 9 mm.

  The cored bar of the charging roller and the illustrated power source are electrically connected, and a predetermined bias is applied to the charging roller by the power source. As a result, the peripheral surface of the photoconductor is uniformly charged to a predetermined polarity and potential.

  The shape of the charging member used in the present invention may take any form such as a magnetic brush or a fur brush in addition to the roller, and can be selected according to the specifications and form of the electrophotographic apparatus. In the case of using a magnetic brush, the magnetic brush is composed of various ferrite particles such as Zn—Cu ferrite as a charging member, a non-magnetic conductive sleeve for supporting it, and a magnet roll included therein. In addition, when using a fur brush, for example, as a material of the fur brush, a fur treated with carbon, copper sulfide, metal or metal oxide is used, and this is wound around a metal or other conductive core metal. By charging or pasting, it becomes a charger.

  Of course, the charging device used in the present invention is not limited to the contact type charging device as described above, but an image forming apparatus in which ozone generated from the charging device is reduced can be obtained. Is preferably used.

<Photoconductor>
As an electrophotographic photoreceptor used in the present invention, a conductive support is heated to 50 ° C. to 400 ° C., and a vacuum deposition method, a sputtering method, an ion plating method, a thermal CVD method, a photo CVD is applied on the support. An amorphous silicon photoconductor (hereinafter referred to as “a-Si photoconductor”) having a photoconductive layer made of a-Si can be used by a film forming method such as a plasma CVD method. Among them, a plasma CVD method, that is, a method in which a source gas is decomposed by direct current, high frequency or microwave glow discharge to form an a-Si deposited film on a support is preferably used.

The layer structure of the amorphous silicon photoconductor is, for example, as follows. FIG. 8 is a schematic configuration diagram for explaining a layer configuration. In the electrophotographic photoreceptor 500 shown in FIG. 8A, a photoconductive layer 502 made of a-Si: H, X and having photoconductivity is provided on a support 501. Here, X represents a halogen group element.
An electrophotographic photoreceptor 500 shown in FIG. 8B includes a photoconductive layer 502 made of a-Si: H, X and having photoconductivity, and an amorphous silicon surface layer 503 on a support 501. It is configured. An electrophotographic photoreceptor 500 shown in FIG. 8C has a photoconductive layer 502 made of a-Si: H, X and having photoconductivity on a support 501, an amorphous silicon surface layer 503, And an amorphous silicon based charge injection blocking layer 504. In the electrophotographic photoreceptor 500 shown in FIG. 8D, a photoconductive layer 502 is provided on a support 501. The photoconductive layer 502 includes a charge generation layer 505 made of a-Si: H, X and a charge transport layer 506, and an amorphous silicon-based surface layer 503 is provided thereon.

  The support for the photoreceptor may be conductive or electrically insulating. Examples of the conductive support include metals such as Al, Cr, Mo, Au, In, Nb, Te, V, Ti, Pt, Pd, and Fe, and alloys thereof such as stainless steel. Also, at least the surface on the side where the photosensitive layer is to be formed of an electrically insulating support such as polyester, polyethylene, polycarbonate, cellulose acetate, polypropylene, polyvinyl chloride, polystyrene, polyamide or other synthetic resin film or sheet, glass or ceramic. A conductively treated support can also be used.

  The shape of the support can be a cylindrical or plate-like or endless belt with a smooth or uneven surface, and the thickness thereof is appropriately determined so that a desired photoreceptor for an image forming apparatus can be formed. When flexibility as a photoreceptor for an image forming apparatus is required, it can be made as thin as possible within a range where the function as a support can be sufficiently exhibited. However, the support is usually 10 μm or more from the viewpoints of manufacturing and handling, such as mechanical strength.

  In the amorphous silicon photoconductor that can be used in the present invention, a charge injection blocking layer that functions to block charge injection from the conductive support side is provided between the conductive support and the photoconductive layer as necessary. It is more effective to provide this (FIG. 8C). That is, the charge injection blocking layer has a function of blocking charge injection from the support side to the photoconductive layer side when the photosensitive layer is subjected to a charging process with a certain polarity on its free surface. When charged, it has a so-called polarity dependency that does not exhibit such a function. In order to provide such a function, the charge injection blocking layer contains a relatively large number of atoms for controlling conductivity as compared with the photoconductive layer.

  The layer thickness of the charge injection blocking layer is preferably from 0.1 to 5 μm, more preferably from 0.3 to 4 μm, and most preferably from 0.5 to 5 in view of obtaining desired electrophotographic characteristics and economic effects. It is desirable to be 3 μm.

  The photoconductive layer is formed on the undercoat layer as necessary, and the layer thickness of the photoconductive layer 502 is appropriately determined as desired from the viewpoint of obtaining desired electrophotographic characteristics and economic effects, and preferably It is desirable that the thickness is 1 to 100 μm, more preferably 20 to 50 μm, and most preferably 23 to 45 μm.

  The charge transport layer is a layer mainly having a function of transporting charges when the photoconductive layer is functionally separated. The charge transport layer includes at least silicon atoms, carbon atoms, and fluorine atoms as constituent elements, and is formed of a-SiC (H, F, O) including hydrogen atoms and oxygen atoms as required. It has conductive properties, particularly charge retention properties, charge generation properties, and charge transport properties. In the present invention, it is particularly preferable to contain an oxygen atom.

  The layer thickness of the charge transport layer is appropriately determined as desired from the viewpoint of obtaining desired electrophotographic characteristics and economic effects, and the charge transport layer is preferably 5 to 50 μm, more preferably 10 to 40 μm, Optimally, it is desirably 20 to 30 μm.

  The charge generation layer is a layer mainly having a function of generating charges when the photoconductive layer is functionally separated. This charge generation layer is composed of a-Si: H containing at least silicon atoms as components and substantially no carbon atoms and, if necessary, hydrogen atoms, and has desired photoconductive properties, particularly charge generation properties. , Has charge transport properties.

  The layer thickness of the charge generation layer is appropriately determined as desired from the viewpoint of obtaining desired electrophotographic characteristics and economic effects, etc., preferably 0.5 to 15 μm, more preferably 1 to 10 μm, optimally 1 ˜5 μm.

  If necessary, the amorphous silicon photoreceptor that can be used in the present invention can be provided with a surface layer on the photoconductive layer formed on the support as described above. It is preferable to form a surface layer. This surface layer has a free surface, and is provided to achieve the object of the present invention mainly in moisture resistance, continuous repeated use characteristics, electrical pressure resistance, use environment characteristics, and durability.

  The thickness of the surface layer in the present invention is usually 0.01 to 3 μm, preferably 0.05 to 2 μm, and most preferably 0.1 to 1 μm. If the layer thickness is less than 0.01 μm, the surface layer is lost due to wear or the like during use of the photoreceptor, and if it exceeds 3 μm, electrophotographic characteristics such as an increase in residual potential are observed.

  Amorphous silicon photoconductors have high surface hardness, high sensitivity to long-wavelength light such as semiconductor lasers (770 to 800 nm), etc., and almost no deterioration due to repeated use. Therefore, high-speed copying machines and laser beam printers are used. It is used as an electrophotographic photoreceptor such as (LBP).

<Fixing device>
As the fixing device in the present invention, a so-called surf fixing device that rotates and fixes a fixing film as shown in FIG. 9 is used. In detail, the fixing film is an endless belt-like heat-resistant film, and is fixed and supported by a driving roller, a driven roller, and a heater support provided below the rollers, which are support rotating members of the film. The heating body is arranged in a suspended manner.

  The driven roller also serves as a tension roller for the fixing film, and the fixing film is rotationally driven in the clockwise direction by the rotational driving of the driving roller in the clockwise direction in the drawing. This rotational driving speed is adjusted to a speed at which the transfer material and the fixing film are equal in the fixing nip region L where the pressure roller and the fixing film are in contact with each other.

  Here, the pressure roller is a roller having a rubber elastic layer having good releasability, such as silicon rubber, and a contact pressure of 4 to 10 kg of total pressure against the fixing nip region L while rotating counterclockwise. With pressure contact.

  The fixing film preferably has excellent heat resistance, releasability and durability, and a thin film having a total thickness of 100 μm or less, preferably 40 μm or less is used. For example, at least an image of a single layer film of a heat-resistant resin such as polyimide, polyetherimide, PES (polyether sulfide), PFA (tetrafluoroethylene bar fluoroalkyl vinyl ether copolymer resin), or a composite layer film, for example, a 20 μm thick film The contact surface is coated with a release coating layer of PTFE (tetrafluoroethylene resin), PFA or other fluororesin added with a conductive material to a thickness of 10 μm, or an elastic layer such as fluororubber or silicon rubber. It is a thing.

In FIG. 9, the heating body of the present embodiment is composed of a flat substrate and a fixing heater, and the flat substrate is made of a material having high thermal conductivity and high electrical resistivity such as alumina, and is a surface in contact with the fixing film. Has a fixing heater formed of a resistance heating element in the longitudinal direction. Such a fixing heater is formed by coating an electric resistance material such as Ag / Pd or Ta ₂ N in a linear or belt shape by screen printing or the like. In addition, electrodes (not shown) are formed at both ends of the fixing heater, and the resistance heating element generates heat when energized between the electrodes. Furthermore, a fixing temperature sensor constituted by a thermistor is provided on the surface of the substrate opposite to the surface provided with the fixing heater.

  The temperature information of the substrate detected by the fixing temperature sensor is sent to a control unit (not shown), and the amount of electric power supplied to the fixing heater is controlled by the control unit, and the heating body is controlled to a predetermined temperature.

  Of course, the fixing device used in the present invention is not limited to the surf fixing device as described above, but an image forming apparatus using the fixing device capable of reducing the rise time with high efficiency can be obtained. Is preferably used.

<Developing device>
In the developing device used in the embodiment of the present invention, during development, a vibration bias voltage obtained by superimposing an AC voltage on a DC voltage is applied to the developing sleeve as a developing bias by a power source. The background portion potential and the image portion potential are located between the maximum value and the minimum value of the vibration bias potential. As a result, an alternating electric field whose direction changes alternately is formed in the developing portion. In this alternating electric field, the developer toner and carrier vibrate vigorously, and the toner flies off the electrostatic binding force on the developing sleeve and carrier and flies to the photosensitive drum, and adheres corresponding to the latent image on the photosensitive drum. To do.

  The difference between the maximum value and the minimum value of the vibration bias voltage (voltage between peaks) is preferably 0.5 to 5 KV, and the frequency is preferably 1 to 10 KHz. As the waveform of the vibration bias voltage, a rectangular wave, a sine wave, a triangular wave or the like can be used. As described above, the DC voltage component of the vibration bias is a value between the background part potential and the image part potential, but the value closer to the background part potential than the image part potential is more likely to cover the background part potential region. Or, it is preferable for preventing toner adhesion.

  When the vibration bias voltage waveform is a rectangular wave, the duty ratio is preferably 50% or less. Here, the duty ratio is a ratio of time during which the toner is directed to the photosensitive member during one period of the vibration bias. By doing so, the difference between the peak value at which the toner is directed to the photoreceptor and the time average value of the bias can be increased, so that the movement of the toner is further activated and the potential of the latent image surface is increased. It can adhere to the distribution and improve the roughness and resolution. In addition, since the difference between the peak value of the carrier having a charge opposite to that of the toner and the time average value of the bias toward the photosensitive member can be reduced, the movement of the carrier is reduced, and the background portion of the latent image is reduced. The probability of carriers adhering to the substrate can be greatly reduced.

  Of course, the applied bias of the developing device used in the present invention is not limited as described above. However, in order to obtain a high-definition image without roughness, it is preferable to take the above-described form.

[Process cartridge]
FIG. 10 shows a schematic configuration of an image forming apparatus having a process cartridge used in the embodiment of the present invention. In the drawing, a represents the entire process cartridge, b represents a photoreceptor, c represents a charging unit, d represents a developing unit, and e represents a cleaning unit.

  In the present invention, at least the photosensitive member b and the developing unit d are integrally combined as a process cartridge among the above-described components such as the photosensitive member b, the charging device unit c, the developing unit d, and the cleaning unit e. The process cartridge is configured to be detachable from a main body of an image forming apparatus such as a copying machine or a printer.

  In the image forming apparatus having the process cartridge using the electrophotographic toner of the present invention, the photosensitive member is rotationally driven at a predetermined peripheral speed. In the rotation process, the photosensitive member is uniformly charged with a positive or negative predetermined potential on its peripheral surface by the charging unit, and then receives image exposure light from an image exposing unit such as slit exposure or laser beam scanning exposure. An electrostatic image is sequentially formed on the peripheral surface of the body, and the formed electrostatic image is then developed with toner by a developing unit, and the developed toner image is exposed between the photosensitive member and the transfer unit from the paper feeding unit. The transfer material is sequentially transferred to the transfer material fed in synchronization with the rotation of the body. The transfer material that has received the image transfer is separated from the surface of the photosensitive member, introduced into the image fixing means, and fixed on the image, and printed out as a copy (copy). The surface of the photoconductor after the image transfer is cleaned by removing toner remaining after transfer by a cleaning unit, and after further static elimination, it is repeatedly used for image formation.

[Tandem type color image forming apparatus]
An embodiment of a tandem color image forming apparatus of the present invention will be described. As shown in FIG. 3, the tandem type electrophotographic apparatus includes a direct transfer system in which an image on each photoconductor 1 is sequentially transferred onto a sheet s conveyed by a sheet conveying belt 3 by a transfer apparatus 2; As shown in FIG. 4, the images on the respective photoconductors 1 are once sequentially transferred to the intermediate transfer member 4 by the primary transfer device 2, and then the images on the intermediate transfer member 4 are transferred to the sheet s by the secondary transfer device 5. There are indirect transfer systems that perform batch transfer. The transfer device 5 is a transfer conveyance belt, but there is also a roller-shaped method.

  Comparing the direct transfer type and the indirect transfer type, the former arranges the sheet feeding device 6 on the upstream side of the tandem image forming apparatus T on which the photoconductors 1 are arranged, and the fixing device 7 on the downstream side. There is a drawback in that the size increases in the sheet conveying direction. On the other hand, the latter can set the secondary transfer position relatively freely. The sheet feeding device 6 and the fixing device 7 can be arranged so as to overlap with the tandem image forming apparatus T, and there is an advantage that downsizing is possible.

  In the former, in order not to increase the size in the sheet conveying direction, the fixing device 7 is disposed close to the tandem type image forming apparatus T. For this reason, the fixing device 7 cannot be disposed with a sufficient margin that allows the sheet s to bend, and an impact when the leading edge of the sheet s enters the fixing device 7 (particularly with a thick sheet) or fixing. Due to the difference in speed between the sheet conveyance speed when passing through the apparatus 7 and the sheet conveyance speed by the transfer conveyance belt, there is a drawback that the fixing device 7 tends to affect image formation on the upstream side. On the other hand, in the latter case, the fixing device 7 can be disposed with a sufficient margin that the sheet s can be bent, so that the fixing device 7 hardly affects the image formation.

  In view of the above, recently, an indirect transfer type of tandem type electrophotographic apparatus has attracted attention.

  In this type of color electrophotographic apparatus, as shown in FIG. 4, the transfer residual toner remaining on the photoreceptor 1 after the primary transfer is removed by the photoreceptor cleaning device 8 to clean the surface of the photoreceptor 1. In preparation for another image formation. Further, the transfer residual toner remaining on the intermediate transfer body 4 after the secondary transfer is removed by the intermediate transfer body cleaning device 9 to clean the surface of the intermediate transfer body 4 to prepare for image formation again.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 5 shows an embodiment of the present invention, which is a tandem indirect transfer type electrophotographic apparatus. In the figure, reference numeral 100 is a copying apparatus main body, 200 is a paper feed table on which the copying apparatus is placed, 300 is a scanner mounted on the copying apparatus main body 100, and 400 is an automatic document feeder (ADF) further mounted thereon. The copying machine main body 100 is provided with an endless belt-shaped intermediate transfer member 10 at the center.

Then, as shown in FIG. 5, in the illustrated example, it is wound around three support rollers 14, 15, and 16 so that it can be rotated and conveyed clockwise in the figure.
In this illustrated example, an intermediate transfer body cleaning device 17 for removing residual toner remaining on the intermediate transfer body 10 after image transfer is provided on the left of the second support roller 15 among the three.

  Further, among the three images, four images of yellow, cyan, magenta, and black are arranged on the intermediate transfer member 10 stretched between the first support roller 14 and the second support roller 15 along the conveyance direction. The tandem image forming apparatus 20 is configured by arranging the forming units 18 side by side.

  An exposure device 21 is further provided on the tandem image forming apparatus 20 as shown in FIG. On the other hand, a secondary transfer device 22 is provided on the side opposite to the tandem image forming apparatus 20 with the intermediate transfer body 10 interposed therebetween. In the illustrated example, the secondary transfer device 22 is configured by spanning a secondary transfer belt 24, which is an endless belt, between two rollers 23, and is pressed against the third support roller 16 via the intermediate transfer body 10. The image on the intermediate transfer body 10 is transferred to a sheet.

  A fixing device 25 for fixing the transfer image on the sheet is provided beside the secondary transfer device 22. The fixing device 25 is configured by pressing a pressure roller 27 against a fixing belt 26 that is an endless belt.

  The secondary transfer device 22 described above also has a sheet transport function for transporting the image-transferred sheet to the fixing device 25. Of course, a transfer roller or a non-contact charger may be arranged as the secondary transfer device 22, and in such a case, it is difficult to provide this sheet conveying function together.

  In the illustrated example, a sheet reversing device 28 for reversing the sheet so as to record an image on both sides of the sheet is provided below the secondary transfer device 22 and the fixing device 25 in parallel with the tandem image forming device 20 described above. Is provided.

  Now, when making a copy using this color electrophotographic apparatus, a document is set on the document table 30 of the automatic document feeder 400. Alternatively, the automatic document feeder 400 is opened, a document is set on the contact glass 32 of the scanner 300, and the automatic document feeder 400 is closed and pressed by it.

  When a start switch (not shown) is pressed, when the document is set on the automatic document feeder 400, the document is transported and moved onto the contact glass 32, and then the document is set on the other contact glass 32. At that time, the scanner 300 is immediately driven to travel the first traveling body 33 and the second traveling body 34. Then, the first traveling body 33 emits light from the light source and further reflects the reflected light from the document surface toward the second traveling body 34 and is reflected by the mirror of the second traveling body 34 and passes through the imaging lens 35. The document is placed in the reading sensor 36 and the original content is read.

  When a start switch (not shown) is pressed, one of the support rollers 14, 15 and 16 is rotationally driven by a drive motor (not shown), the other two support rollers are driven to rotate, and the intermediate transfer body 10 is rotated and conveyed. To do. At the same time, the individual image forming means 18 rotates the photoconductor 40 to form black, yellow, magenta, and cyan monochrome images on each photoconductor 40. Then, along with the conveyance of the intermediate transfer member 10, the single color images are sequentially transferred to form a composite color image on the intermediate transfer member 10.

  On the other hand, when a start switch (not shown) is pressed, one of the paper feed rollers 42 of the paper feed table 200 is selectively rotated, and the sheet is fed out from one of the paper feed cassettes 44 provided in multiple stages in the paper bank 43, and the separation roller 45. Then, the sheets are separated one by one into the paper feed path 46, transported by the transport roller 47, guided to the paper feed path 48 in the copying machine main body 100, and abutted against the registration roller 49 and stopped.

  Alternatively, the sheet feed roller 50 is rotated to feed out the sheets on the manual feed tray 51, separated one by one by the separation roller 52, put into the manual feed path 53, and abutted against the registration roller 49 and stopped.

  Then, the registration roller 49 is rotated in synchronization with the composite color image on the intermediate transfer member 10, the sheet is fed between the intermediate transfer member 10 and the secondary transfer device 22, and transferred by the secondary transfer device 22. A color image is recorded on the sheet.

  The image-transferred sheet is conveyed by the secondary transfer device 22 and sent to the fixing device 25. The fixing device 25 applies heat and pressure to fix the transferred image, and then the switching roller 55 is used to switch the discharge roller. The paper is discharged at 56 and stacked on the paper discharge tray 57. Alternatively, it is switched by the switching claw 55 and put into the sheet reversing device 28, where it is reversed and guided again to the transfer position, and an image is recorded also on the back surface, and then discharged onto the discharge tray 57 by the discharge roller 56.

  On the other hand, the intermediate transfer body 10 after the image transfer is removed by the intermediate transfer body cleaning device 17 to remove residual toner remaining on the intermediate transfer body 10 after the image transfer, so that the tandem image forming apparatus 20 can prepare for another image formation.

  Here, the registration roller 49 is generally used while being grounded, but it is also possible to apply a bias for removing paper dust from the sheet.

  In the tandem image forming apparatus 20 described above, the individual image forming means 18 includes, for example, a charging device 60, a developing device 61, and a primary transfer device around a drum-shaped photoconductor 40 as shown in FIG. 62, a photoconductor cleaning device 63, a charge removal device 64, and the like. The reference numerals shown in FIG. 6 will be described. 65 is a developer on the developing sleeve, 68 is a stirring paddle, 69 is a partition plate, 71 is a toner density sensor, 72 is a developing sleeve, 73 is a doctor, 75 is a cleaning blade, and 76 is A cleaning brush, 77 is a cleaning roller, 78 is a cleaning blade, 79 is a toner discharge auger, and 80 is a driving device.

<Example>
EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples and comparative examples, but the present invention is not limited only to these examples. In the following examples, “parts” and “%” are based on weight unless otherwise specified.

<Toner shape>
The toner shapes obtained in Examples and Comparative Examples were measured as follows.
(1) Measurement of volume average particle diameter (Dv) and [Dv / Dn] value Volume average particle diameter (Dv) and ratio of volume average particle diameter (Dv) to number average particle diameter (Dn) [Dv / Dn] Was measured by COULTER TA-II (manufactured by COULTER ELECTRONICS, INC). The aperture diameter was 100 μm.

(2) Measurement of average circularity The average circularity can be measured using a flow type particle image analyzer FPIA-2100 manufactured by Sysmex Corporation. The measurement is performed as follows.
After preparing a 1% NaCl aqueous solution using first grade sodium chloride, 0.1 to 5 ml of a surfactant, preferably alkylbenzene sulfonate, as a dispersant is added to 50 to 100 ml of a 0.45 μm filter, and a sample is added. 1-10 mg is added. This was subjected to a dispersion treatment for 1 minute with an ultrasonic disperser, and measurement was performed using a dispersion liquid in which the particle concentration was adjusted to 5000 to 15000 particles / μl. The diameter of a circle having the same area as a two-dimensional image captured by a CCD camera is assumed to be the equivalent circle diameter, and the equivalent circle diameter of 0.6 μm or more is effective from the accuracy of CCD pixels, and is used for calculating the average circularity. It was. The average circularity can be obtained by calculating the circularity of each particle, adding up the circularity of each particle, and dividing by the total number of particles. The average circularity of each particle can be calculated by dividing the circumference of a circle having the same projected area as the particle image by the circumference of the particle projection image.

<Two-component developer>
When evaluating the image quality and the like of a copied image in this example and the comparative example, the performance of the toner of the present invention as a two-component developer was evaluated.

  As a carrier used for the two-component developer, a ferrite carrier having an average particle diameter of 35 μm coated with a silicone resin with an average thickness of 0.5 μm is used, and 7 parts by weight of each color toner is added to 100 parts by weight of the carrier. A developer was prepared by uniformly mixing and charging using a type of tumbler mixer in which the container was rolled and stirred.

  The carrier was prepared as follows. As a core material, 5000 parts of Mn ferrite particles (weight average diameter: 35 μm), and as a coating material, 450 parts of toluene, 450 parts of silicone resin SR2400 (made by Toray Dow Corning Silicone, nonvolatile content 50%), aminosilane SH6020 ( Using a coating liquid prepared by dispersing 10 parts of Toray Dow Corning Silicone) and 10 parts of carbon black with a stirrer for 10 minutes, the core material, the coating liquid, and a rotating bottom plate disk in the fluidized bed The coating liquid was applied to the core material by applying the coating liquid while forming a swirling flow provided with stirring blades. The obtained coated material was baked in an electric furnace at 250 ° C. for 2 hours to obtain the carrier.

<Image quality evaluation machine for copied images>
In the toners obtained in the following examples and comparative examples, the four color developing sections sequentially develop the developer on each belt photoreceptor, sequentially transfer them to the intermediate transfer body, and transfer the four colors onto paper or the like at once. Type full-color laser printer Ypsio 8000 (manufactured by Ricoh) is equipped with a contact-type charging device, an amorphous silicon photoreceptor, a surf fixing device , and developing means , and the developing means is a vibration in which an alternating voltage is superimposed on a DC voltage as a developing bias. An evaluation machine A that has been improved so that a bias voltage is applied, and that the photosensitive member, the charging device, the developing means, and the cleaning device are integrally combined as a process cartridge. Evaluation was performed by an evaluation machine B in which the fixing device of the evaluation machine A was improved to an oilless surf fixing device. In this example and comparative example, the same developer was put in each of the four color developing sections, and the image quality and the like were evaluated in the single color mode.

<Evaluation items>
The following items were evaluated for the performance of the toners obtained in the examples and comparative examples.
Regarding the evaluation of the image quality of the copied image, the evaluation was performed after running 10,000 image charts having a 7% image area.

(1) External additive burying property After storing for 1 week in an environment of 40 ° C. and 80%, the toner surface after stirring for 1 hour in the developing unit of Evaluation Machine A was subjected to FE-SEM (Hitachi, field emission scanning). Observation with a scanning electron microscope S-4200), the buried state of the external additive was observed. Those with little burial are good, and in Table 2, when burial is almost impossible to confirm, it is ◎, when it is not all but partially burial is ◯, most external additives are Although it is buried but is in a state where the presence of the external additive can be confirmed on the toner surface, it is Δ, and almost all of the external additive is buried, and the presence of the external additive cannot be confirmed on the toner surface. When it is in a state, it is indicated by ×.

(2) Charging stability Using the evaluation machine B, a continuous image output durability test with a 5% image area ratio 5% chart was performed to evaluate the change in the charge amount. 1 g of developer was weighed and the change in charge amount was determined by the blow-off method. In Table 2, when the change in the charge amount is 5 μC / g or less, it is indicated by ◎, when it exceeds 5 μC / g and 10 μC / g or less, it is indicated by ◯, and when it exceeds 10 μC / g, it is indicated by ×.

(3) Image Density Using Evaluator A, 150,000 sheets of 50% image area image charts were output in a single color mode, then a solid image was output to 6000 paper manufactured by Ricoh, and the image density was X-Rite. Measurement was carried out by (manufactured by X-Rite). In Table 2, when the measured value is 1.8 or more and less than 2.2, it is ◎, when it is 1.4 or more and less than 1.8, it is ◯, when it is 1.2 or more and less than 1.4, it is △, And when less than 1.2, it displayed by x.

(4) Image granularity and sharpness Using the evaluation machine B, a photographic image was output in a single color, and the degree of granularity and sharpness was visually evaluated. Table 2 shows that the degree is ◎ when it is the same as offset printing, ◯ when it is slightly worse than offset printing, △ when it is much worse than offset printing, and about the conventional electrophotographic image If it is very bad, it is displayed as x.

(5) Background stain After using the evaluation machine A to output 30,000 image charts of 50% image area in the single color mode, the blank image is stopped during development, and the developer on the photoconductor after development is removed. The tape was transferred, and the difference from the image density of the untransferred tape was measured with a 938 spectrodensitometer (manufactured by X-Rite). The difference between the two image densities is good with no background stain, and in Table 2, when the measured image density is 0.02 or less, ◎, and when 0.03 to 0.06 In the case of .largecircle., 0.07 to 0.12, ".DELTA." And in case of 0.13 or more, "x".

(6) White spots inside character images Using the evaluation machine A, after running 30,000 image charts with a 50% image area in single color mode, the character image is output to a Ricoh type DX OHP sheet. The toner non-transfer frequency at which the inside of the line image of the character part is lost was compared with the stage sample, and was evaluated in five stages of ranks 1 to 5. Also, rank 5 has the least white spots and rank 1 has the most white spots. In Table 2, when it was rank 5, it was indicated by ◎, when it was rank 4, it was indicated by ◯, when it was rank 3, it was indicated by △, and when it was rank 2 or 1, it was indicated by x.

(7) Toner fluidity A powder tester (PT-N type, manufactured by Hosokawa Micron) is loaded with meshes of 75 μm, 45 μm, and 22 μm openings in order from the top, and the toner base particles are placed on the uppermost 75 μm mesh. 2 g was added, and a vibration of 1 mm in the vertical direction was applied for 10 seconds, and the degree of fluidity (aggregation degree) of the toner base particles was calculated from the amount of toner remaining on each mesh by the following formula and evaluated.

Aggregation degree (%) = [{5 × (remaining toner amount (g)} on 75 μm mesh) + 3 × {remaining toner amount (g)} on 45 μm mesh} + {remaining toner amount (g)} on 22 μm mesh] × 10
(If all of the toner base particles 2g pass through the 22 μm mesh, the degree of aggregation is 0%, and if all of the toner base particles remain on the 75 μm mesh, the degree of aggregation is 100%.)
In Table 2, when the degree of aggregation is 8% or less, it is ◎, when it exceeds 8% and 15% or less, it is ◯, when it exceeds 15% and 25% or less, it is Δ, and it exceeds 25% and 40% or less. In the case of, it is indicated by ×, and when it exceeds 40%, it is indicated by xx.

(8) Fixability Using the evaluation machine A, a solid image and a transfer image of plain paper and cardboard (type 6200 made by Ricoh and copy printing paper <135> made by NBS Ricoh) with a solid image of 0.85 ± 0.1 mg / cm ² The fixing performance was evaluated by the toner adhesion amount. The fixing test was conducted by changing the temperature of the fixing belt, and the upper limit temperature at which hot offset did not occur on plain paper was defined as the upper limit temperature for fixing. Further, the minimum fixing temperature was measured with a thick paper. The lower limit fixing temperature was determined as the fixing lower limit temperature at the fixing roll temperature at which the residual ratio of the image density after rubbing the obtained fixed image with a pad was 70% or more. The fixing upper limit temperature is shown in Table 2 as ◎ for 190 ° C or more, ◯ for 180 ° C or more and less than 190 ° C, △ for 170 ° C or more and less than 180 ° C, and less than 170 ° C. In the case of, it is indicated by ×. As for the lower limit fixing temperature, it is shown in Table 2 that it is １３５ when it is 135 ° C. or lower, ◯ when it is higher than 135 ° C. and lower than 145 ° C., Δ when it is higher than 145 ° C. and lower than 155 ° C., and 155 When it exceeded ° C, it was displayed as x.

(Synthesis of organic fine particle emulsion)
In a reaction vessel equipped with a stirrer and a thermometer, 683 parts of water, 11 parts of sodium salt of ethylene oxide methacrylate adduct sulfate (Eleminol RS-30, manufactured by Sanyo Chemical Industries), 83 parts of styrene, 83 parts of methacrylic acid, When 110 parts of butyl acrylate and 1 part of ammonium persulfate were charged and stirred for 15 minutes at 400 rpm, a white emulsion was obtained. This was heated to raise the system temperature to 75 ° C. and reacted for 5 hours. Further, 30 parts of a 1% ammonium persulfate aqueous solution was added, and the mixture was aged at 75 ° C. for 5 hours to give a vinyl resin (a copolymer of styrene-methacrylic acid-butyl acrylate-methacrylic acid ethylene oxide adduct sulfate sodium salt). An aqueous dispersion was obtained. This is designated as [fine particle dispersion 1].

  The volume average particle diameter of [fine particle dispersion 1] measured using LA-920 (manufactured by HORIBA) as a sample was 105 nm. Further, a part of [Fine Particle Dispersion 1] was dried to isolate the resin component. The resin content had a Tg of 59 ° C. and a weight average molecular weight of 150,000.

(Preparation of aqueous phase)
990 parts of water, 80 parts of [fine particle dispersion 1], 37 parts of a 48.5% aqueous solution of dodecyl diphenyl ether disulfonate (Eleminol MON-7, manufactured by Sanyo Chemical Industries), and 90 parts of ethyl acetate were mixed and stirred. A liquid was obtained. This is designated as [Aqueous Phase 1].

(Synthesis of low molecular weight polyester)
In a reaction vessel equipped with a condenser, a stirrer and a nitrogen inlet tube, 229 parts of bisphenol A ethylene oxide 2-mole adduct, 529 parts of bisphenol A propylene oxide 3-mole adduct, 208 parts terephthalic acid, 46 parts adipic acid and dibutyl After charging 2 parts of tin oxide and reacting at 230 ° C. for 8 hours at normal pressure and further 5 hours at a reduced pressure of 10 to 15 mmHg, 44 parts of trimellitic anhydride was added to the reaction vessel, and 180 ° C. and normal pressure. For 2 hours to obtain a polyester. This is referred to as [low molecular polyester 1]. This [low molecular polyester 1] had a number average molecular weight of 2500, a weight average molecular weight of 6700, a Tg of 43 ° C., and an acid value of 25.

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

  Next, 410 parts of [Intermediate polyester 1], 89 parts of isophorone diisocyanate, and 500 parts of ethyl acetate are charged in a reaction vessel equipped with a cooling pipe, a stirrer, and a nitrogen introduction pipe, and reacted at 100 ° C. for 5 hours. An isocyanate group-containing polyester prepolymer was obtained. This is designated as [Prepolymer 1]. This [Prepolymer 1] had a free isocyanate content of 1.53% by weight.

(Synthesis of ketimine)
170 parts of isophoronediamine and 75 parts of methyl ethyl ketone were charged into a reaction vessel equipped with a stirrer and a thermometer, and reacted at 50 ° C. for 5 hours to obtain a blocked amine. This is referred to as [ketimine compound 1]. The amine value of this [ketimine compound 1] was 418.

(Preparation of masterbatch)
1200 parts water, 40 parts carbon black (manufactured by Cabot, Regal 400R), 60 parts polyester resin (manufactured by Sanyo Chemical Industries, RS801), 30 parts water, and mixed with a Henschel mixer (manufactured by Mitsui Mining) The mixture was kneaded at 150 ° C. for 30 minutes using two rolls, rolled and cooled, and pulverized with a pulverizer to obtain a carbon black masterbatch. This is designated as [Masterbatch 1].

(Preparation of oil phase)
A container equipped with a stir bar and a thermometer was charged with 400 parts of [low molecular weight polyester 1], 110 parts of carnauba wax, and 947 parts of ethyl acetate, heated to 80 ° C. with stirring, and maintained at 80 ° C. for 5 hours. Then, it cooled to 30 degreeC over 1 hour. Next, 500 parts of [Masterbatch 1] and 500 parts of ethyl acetate were placed in a container and mixed for 1 hour to obtain a dissolved product. This is referred to as [Raw material solution 1].

  [Raw Material Solution 1] Transfer 1324 parts to a container and use a bead mill (Ultra Visco Mill, manufactured by Imex Co., Ltd.), liquid feeding speed: 1 Kg / hr, disk peripheral speed: 6 m / sec, 0.5 mm zirconia bead filling amount : The wax was dispersed under the conditions of 80% by volume and the number of passes: 3 times. Next, 1324 parts of 65% ethyl acetate solution of [low molecular weight polyester 1] and polymethyl methacrylate resin fine particles MP-1000 (average primary particle size 0.4 μm, manufactured by Soken Chemical Co., Ltd.) as resin fine particles (A) 7 parts were added, and the dispersion liquid was obtained by the number of passes: once using a bead mill under the same conditions as described above. This is designated as [Pigment / Wax Dispersion 1].

(Emulsification)
[Pigment / Wax Dispersion 1] 648 parts, [Prepolymer 1] 154 parts, and [Ketimine Compound 1] 8.5 parts are put in a container and 5,000 rpm using a TK homomixer (manufactured by Tokushu Kika). After mixing for 1 minute, 1200 parts of [Aqueous Phase 1] was added to the container, and the mixture was mixed with a TK homomixer at 10,000 rpm for 20 minutes to obtain an aqueous medium dispersion. This is designated as [Emulsified slurry 1].

(Deorganic solvent)
[Emulsified slurry 1] is put into a container equipped with a stirrer and a thermometer, and after removing the solvent at 30 ° C. for 8 hours, aging is carried out at 45 ° C. for 4 hours to obtain a dispersion in which the organic solvent is distilled off. It was. This is designated as [Dispersion Slurry 1].

(Washing and drying)
[Dispersion Slurry 1] After filtering 100 parts under reduced pressure,
(1) 100 parts of ion-exchanged water was added to the filter cake, mixed with a TK homomixer (rotation speed 12000 rpm for 10 minutes), and then filtered.
(2) 100 parts of 10% aqueous sodium hydroxide solution was added to the filter cake of (1), mixed with a TK homomixer (rotation speed: 12,000 rpm for 30 minutes), and then filtered under reduced pressure.
(3) 100 parts of 10% hydrochloric acid was added to the filter cake of (2), mixed with a TK homomixer (rotation speed: 12000 rpm for 10 minutes), and then filtered.
(4) 300 parts of ion-exchanged water was added to the filter cake of (3), mixed with a TK homomixer (rotation speed: 12000 rpm for 10 minutes), and then filtered twice to obtain a filter cake.
This filter cake was dried at 45 ° C. for 48 hours in a circulating dryer, and sieved with a mesh having a mesh size of 75 μm to obtain toner base particles. This is referred to as [Toner Base 1].

(Mixing of external additives and evaluation of the obtained toner)
100 parts by weight of [Toner Base 1] obtained above and 1.0 part by weight of hydrophobic silica (HDK H2000, manufactured by Clariant Japan) as an external additive are mixed by a Henschel mixer, and passed through a sieve having an opening of 38 μm. The toner was obtained by removing the aggregates. This is referred to as [Toner 1].

The volume average particle diameter (Dv), Dv / Dn, and circularity of [Toner 1] were measured, and the measurement results are shown in Table 1.
7 parts by weight of [Toner 1] with respect to 100 parts by weight of the carrier were uniformly mixed and charged using a type of tumbler mixer in which the container was rolled and stirred to prepare a developer. Table 2 shows the evaluation results for the above evaluation items.

  In the (preparation of oil phase) described in Example 1, in the same manner as in Example 1, except that 1590 parts of resin fine particles (A) were added instead of 1.7 parts of resin fine particles (A). [Toner base 2] and [Toner 2] were obtained. Table 1 and Table 2 show the measured values and evaluation results in the same manner as in Example 1.

In Example 1 (preparation of the oil phase), Example 1 is different from Example 1 except that 3.32 parts of resin fine particles (A) are added instead of 1.7 parts of resin fine particles (A). Similarly, [Toner Base 3] and [Toner 3] were obtained. Table 1 and Table 2 show the measured values and evaluation results in the same manner as in Example 1.

  In the (preparation of oil phase) described in Example 1, in place of 1.7 parts of resin fine particles (A), it was changed to add 105 parts of resin fine particles (A), and the average primary particle diameter was 10 nm. [Toner Base 4] and [Toner 4] were obtained in the same manner as in Example 1 except that 35 parts of hydrophobic silica (HDK H2000, manufactured by Clariant Japan) was added. Table 1 and Table 2 show the measured values and evaluation results in the same manner as in Example 1.

  In the (preparation of oil phase) described in Example 1, in place of 1.7 parts of resin fine particles (A), it was changed to add 105 parts of resin fine particles (A), and the average primary particle diameter was 10 nm. Example 1 except that 35 parts of hydrophobic silica (HDK H2000, manufactured by Clariant Japan) and 18 parts of hydrophobic titanium oxide (MT-150AFM, manufactured by Teika) having an average primary particle size of 15 nm were added. Similarly, [Toner Base 5] and [Toner 5] were obtained. Table 1 and Table 2 show the measured values and evaluation results in the same manner as in Example 1.

  In Example 1 (preparation of oil phase), as resin fine particles (A), instead of 1.7 parts of polymethyl methacrylate resin fine particles MP-1000, polymethyl methacrylate resin fine particles MP-1400 (average primary particle diameter 2 μm, 189 parts by Soken Chemical Co., Ltd.), 114 parts of hydrophobic silica having an average primary particle diameter of 10 nm (HDK H2000, manufactured by Clariant Japan), and hydrophobic titanium oxide having an average primary particle diameter of 15 nm (MT-150AFM, manufactured by Teika) 76 [Toner Base 6] and [Toner 6] were obtained in the same manner as in Example 1 except that the amount of the toner was changed so as to be added. Table 1 and Table 2 show the measured values and evaluation results in the same manner as in Example 1.

  In Example 1 (preparation of oil phase), polymethyl methacrylate resin fine particles MP-1451 (average primary particle size 0. 0) was used instead of 1.7 parts of polymethyl methacrylate resin fine particles MP-1000 as resin fine particles (A). 189 parts of 15 μm, manufactured by Soken Chemical Co., Ltd., 114 parts of hydrophobic silica having an average primary particle diameter of 10 nm (HDK H2000, manufactured by Clariant Japan), and hydrophobic titanium oxide having an average primary particle diameter of 15 nm (MT-150AFM, manufactured by Teika) In addition, in (adjustment of the aqueous phase), instead of 37 parts of a 48.5% aqueous solution of dodecyl diphenyl ether disulfonate (Eleminol MON-7, manufactured by Sanyo Chemical Industries), 45 parts The polymer protective colloid carboxymethylcellulose (cellogen BSH, three [Toner Base 7] and [Toner 7] were obtained in the same manner as in Example 1 except that 15 parts of a 3.0% aqueous solution (made by Yosei Kasei Kogyo) was added. Table 1 and Table 2 show the measured values and evaluation results in the same manner as in Example 1.

  In Example 1 (preparation of oil phase), 189 parts of resin fine particles (A) instead of 1.7 parts of resin fine particles (A), hydrophobic silica having an average primary particle diameter of 10 nm (HDK H2000, manufactured by Clariant Japan) 114 parts and 76 parts of hydrophobic titanium oxide having an average primary particle size of 15 nm (MT-150AFM, manufactured by Teica) were added, and in (adjustment of aqueous phase), 48.5 of sodium dodecyl diphenyl ether disulfonate was added. Instead of 37 parts of a 30% aqueous solution (Eleminol MON-7, manufactured by Sanyo Chemical Industries), 30 parts were replaced with 28 parts of a 3.0% aqueous solution of polymer protective colloid carboxymethylcellulose (Serogen BSH, manufactured by Sanyo Chemical Industries). [Toner Base 8] and [Toner 8] were obtained in the same manner as Example 1 except for the addition. Table 1 and Table 2 show the measured values and evaluation results in the same manner as in Example 1.

  In Example 1 (preparation of oil phase), 189 parts of resin fine particles (A) instead of 1.7 parts of resin fine particles (A), hydrophobic silica having an average primary particle diameter of 10 nm (HDK H2000, manufactured by Clariant Japan) 114 parts and 76 parts of hydrophobic titanium oxide having an average primary particle size of 15 nm (MT-150AFM, manufactured by Teica) were added, and in (Adjustment of aqueous phase), a 48.5% aqueous solution of sodium dodecyl diphenyl ether disulfonate (Eleminol MON-7, manufactured by Sanyo Chemical Industries) 37 parts instead of 30 parts, and added 42 parts of a 3.0% aqueous solution of polymer protective colloid carboxymethylcellulose (Serogen BSH, manufactured by Sanyo Chemical Industries), Except that the TK homomixer rotation speed after mixing [Aqueous Phase 1] was changed from 10,000 rpm to 8,000 rpm. In the same manner as in Example 1, [Toner Base 9] and [Toner 9] were obtained. Table 1 and Table 2 show the measured values and evaluation results in the same manner as in Example 1.

  In Example 9 (adjustment of the oil phase), as the resin fine particles (A), instead of the polymethyl methacrylate resin fine particles MP-1000, poly (styrene-methyl methacrylate) resin fine particles MP-5000 (average primary particle size 0. [Toner Base 10] and [Toner 10] were obtained in the same manner as in Example 9 except that the thickness was changed to 4 μm, manufactured by Soken Chemical Co., Ltd. Table 1 and Table 2 show the measured values and evaluation results in the same manner as in Example 1.

[Comparative Example 1]
[Toner Base 11] and [Toner 11] were obtained in the same manner as in Example 1 except that the resin fine particles (A) were not added in the (preparation of oil phase) described in Example 1. Table 1 and Table 2 show the measured values and evaluation results in the same manner as in Example 1.
In Table 1, the numerical value of “added amount of resin fine particles (A) (% by weight)” indicates the ratio of resin fine particles (A) in the toner.

  According to the present invention, the charge amount distribution is sharp, the charging device, the developing device, the photosensitive member and the intermediate transfer member are not contaminated, and it is appropriate to use a high-quality image, particularly a large number of sheets repeatedly for a long time. As an electrophotographic toner that provides image density and produces very little background stains, it can be used as an electrophotographic toner used in electrophotographic developing devices such as full-color copiers, full-color laser printers, and full-color plain paper fax machines. High availability.

1 is a schematic configuration diagram illustrating an example of an image forming apparatus of the present invention. It is a schematic block diagram which shows the other example of the image forming apparatus of this invention. It is a schematic block diagram which shows the other example of the image forming apparatus of this invention. It is a schematic block diagram which shows the other example of the image forming apparatus of this invention. It is a schematic block diagram which shows the other example of the image forming apparatus of this invention. It is a schematic block diagram which shows the other example of the image forming apparatus of this invention. It is explanatory drawing of the outline of a roller-type contact charging device. It is the schematic which shows the example of a structure of a photoreceptor. FIG. 2 is a schematic explanatory diagram of a surf fixing device. It is a schematic explanatory drawing which shows an example of the process cartridge of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Photoconductor 20 Charging roller 30 Exposure apparatus 40 Developing apparatus 41 Developing belt 42 Developing tank 43 Pumping roller 44 Coating roller 45 Developing unit 50 Intermediate transfer body 51 Suspension roller 52 Corona charger 53 Constant current source 60 Cleaning device 70 Static elimination lamp 80 Transfer Roller 90 Cleaning device 100 Transfer paper

Claims (17)

At least an organic solvent phase in which the functional group-containing polyester-based resin is dissolved and the resin fine particles (A) are dispersed;
An active hydrogen-containing compound,
In the aqueous medium phase in which the resin fine particles (B) are dispersed,
An electrophotographic toner formed from a dispersion obtained by subjecting the functional group-containing polyester resin and the active hydrogen-containing compound to an extension reaction and / or a crosslinking reaction,
An electrophotographic toner comprising the resin fine particles (A) therein.   2. The electrophotographic toner according to claim 1, wherein the resin fine particles (A) comprise a styrene- (meth) acrylic acid ester copolymer or a (meth) acrylic acid ester polymer. The toner for electrophotography according to claim 1 or 2, wherein the average particle diameter of the resin fine particles (A) is characterized in that it is a 0.15～2.0Myuemu. The toner for electrophotography according to any one of claims 1 to 3 , further comprising inorganic fine particles together with the resin fine particles (A). The toner for electrophotography according to claim 4 , wherein the inorganic fine particles are silica, or silica and titanium oxide . 6. The toner base particles according to claim 4 or 5 , wherein the total amount of inorganic fine particles obtained by fluorescent X-ray analysis is 0.1 to 30% by weight based on the toner base particles. Toner for electrophotography.   7. The toner base particle, wherein the element concentration derived from inorganic fine particles on the surface of the toner base particle obtained by XPS method is 0.1 to 15 atomic% (number of atoms%). The toner for electrophotography according to any one of the above. The toner for electrophotography has a volume average particle diameter (Dv) of 2 to 7 μm, and a ratio of the volume average particle diameter (Dv) to the number average particle diameter (Dn): the value of Dv / Dn is 1.25 or less. The toner for electrophotography according to any one of claims 1 to 7 , wherein the toner is an electrophotographic toner. The electrophotographic toner has an average circularity of the toner for electrophotography according to any one of claims 1-8, characterized in that the substantially spherical particles is 0.950 to 0.990 . A two-component electrophotographic developer comprising the electrophotographic toner according to any one of claims 1 to 9 and a carrier comprising magnetic particles. The electrostatic image on the electrostatic image bearing member is developed by an electrostatic image developing means to form a toner image, and a transfer means is brought into contact with the surface of the electrostatic charge image bearing member via a recording material so that the toner image is transferred. An image forming apparatus for electrostatic transfer to a recording material, wherein the electrophotographic toner according to any one of claims 1 to 9 is used as a developer. The electrostatic image on the electrostatic image bearing member is developed by an electrostatic image developing means to form a toner image, and a transfer means is brought into contact with the surface of the electrostatic charge image bearing member via a recording material so that the toner image is transferred. In an image forming apparatus for electrostatic transfer to a recording material, the two-component electrophotographic developer according to claim 10 is used as the developer. The image forming apparatus according to claim 11 or 12 , wherein the electrostatic charge image carrier is charged by bringing a charging member into contact with the electrostatic charge image carrier and applying a voltage to the charging member. The image forming apparatus according to claim 11 , wherein an alternating electric field is applied to the electrostatic image developing unit when developing the latent image on the electrostatic image carrier. The image forming apparatus according to claim 11 , wherein the electrostatic image carrier is an amorphous silicon electrostatic image carrier. A recording material on which an unfixed image is formed after electrostatic transfer includes a heating body provided with a heating element, a film in contact with the heating body, and a pressure member in pressure contact with the heating body through the film. The image forming apparatus according to claim 11 , wherein the fixing unit includes a fixing unit that heat-fixes the unfixed image by passing between the film and the pressure member. A process cartridge which constitutes a part of the image forming apparatus and is detachable, and at least an electrostatic charge image carrier and a developing unit are integrally supported inside, and the developing unit is claimed in claim 1. 10. A process cartridge using the electrophotographic toner according to any one of items 9 to 9 .

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