JP4825721B2 - Electrophotographic developer, image forming method, process cartridge, and image forming apparatus - Google Patents

Description

  The present invention relates to an electrophotographic developer, an image forming method, a process cartridge, and an image forming apparatus.

  In an electrophotographic image forming method, an electrostatic latent image is formed on an image carrier (also referred to as a photoconductor) by charging and exposure, and then developed with a developer containing toner to produce a visible image. A toner image is formed. Further, the toner image is transferred onto the recording material and then fixed onto the recording material. On the other hand, toner remaining on the image carrier without being transferred to the recording material is cleaned by a cleaning member such as a blade disposed in pressure contact with the surface of the image carrier.

  It is known that toner used in electrophotography can be produced by a pulverization method. The pulverization method is a method for producing a toner by melt-kneading a thermoplastic resin as a binder resin to which a colorant and additives used as necessary are added, followed by pulverization and classification. However, the toner obtained in this way has a large particle size and it is difficult to form a high-quality image.

  Therefore, toners are manufactured using a polymerization method or an emulsion dispersion method. As a polymerization method, a suspension polymerization method is known in which a monomer, a polymerization initiator, a colorant, a charge control agent, and the like are added to an aqueous medium containing a dispersant while stirring to form oil droplets and then polymerized. It has been. Also known is an association method in which particles obtained by emulsion polymerization or suspension polymerization are aggregated and fused. However, in such a method, although the particle diameter of the toner can be reduced, it is limited to the polymer obtained by radical polymerization of the main component of the binder resin. A toner having an epoxy resin as a main component of a binder resin cannot be produced.

  On the other hand, there is known a method for producing a toner by using an emulsification dispersion method in which a mixture of a binder resin, a colorant and the like is mixed with an aqueous medium and emulsified (see, for example, Patent Documents 1 and 2). . Thereby, in addition to being able to cope with the reduction in the particle size of the toner, the selection range of the binder resin is widened. However, when such a method is used, fine particles are generated and emulsification loss occurs.

  A method for producing a toner by emulsifying and dispersing a polyester resin and then aggregating and fusing the obtained particles is known (for example, see Patent Documents 3 and 4). Thereby, since generation | occurrence | production of microparticles | fine-particles can be suppressed, an emulsification loss can be reduced. However, the toner obtained by using the polymerization method or the emulsification dispersion method tends to be spherical due to the interfacial tension of the droplets generated in the dispersion step. For this reason, when the blade cleaning method is used, there is a problem that the spherical toner rotates between the cleaning blade and the photosensitive member and enters the gap and is not easily cleaned.

  A method is known in which high-speed stirring is performed before the polymerization is completed and mechanical force is applied to the particles to make the particles indefinite (for example, see Patent Document 5). However, when such a method is used, there is a problem that the dispersion state becomes unstable and the particles tend to coalesce. Also known is a method of obtaining aggregated particles having a particle diameter of 5 to 25 μm by aggregating particles using polyvinyl alcohol having a specific degree of saponification as a dispersant. However, the aggregate particles obtained in this way have a problem that the particle diameter tends to be large.

  There is known a method in which a filler is added to an organic solvent together with a toner composition to make particles irregular (see, for example, Patent Document 6). However, when a filler is added to the toner, the viscoelasticity of the toner increases, and the lower limit of fixing is observed. In addition, when the filler is present on the toner surface, there is almost no increase in the viscoelasticity of the toner. However, if a substance such as a filler is present on the toner surface layer, the seepage of the wax is inhibited or the binder resin is dissolved. Inhibiting the removal, constant temperature fixing property, and hot offset property are also observed.

  Furthermore, a charge control agent in which ions such as metal cations existing between layers of the layered inorganic mineral are modified with ions such as organic cations has been developed, and it has been proposed to use this for electrophotographic toners (for example, patent documents). 7, 8, 9, 10).

  On the other hand, for the carrier, prevention of filming of toner components on the carrier surface, formation of a uniform carrier surface, prevention of surface oxidation, prevention of moisture sensitivity deterioration, extension of developer life, prevention of carrier adhesion to the photoreceptor surface, photosensitivity For the purpose of protecting the body from scratches or abrasion by the carrier, controlling the charge polarity or adjusting the charge amount, a hard and high-strength coating layer is usually provided by coating with an appropriate resin material. ing.

  For example, those coated with a specific resin material (for example, see Patent Document 11), or those in which various additives are added to the coating layer (for example, Patent Documents 12, 13, 14, 15, 16, 17, 18, 19), an example in which an additive is further attached to the carrier surface (see, for example, Patent Document 20), or an example in which a conductive layer larger than the thickness of the coating layer is contained in the coating layer. (For example, refer to Patent Document 21) and the like have been proposed. In addition, a benzoguanamine-n-butyl alcohol-formaldehyde copolymer as a main component is used for a carrier coating material (for example, see Patent Document 22), and a cross-linked product of a melamine resin and an acrylic resin is used as a carrier coating material (for example, Patent Document 23) has been proposed.

  Furthermore, there is an increasing demand for faster and more beautiful image forming apparatuses, and the speed of machines in recent years has increased significantly. Along with this, the stress received by the developer has also increased dramatically, and it has become impossible to obtain a sufficient life even with a carrier that has been long-lived in the past. In addition, carbon black has been conventionally used as a carrier resistance adjusting agent. However, there is a concern about color stains caused by film removal and / or migration of carbon black into a color image due to carbon black detachment. As a countermeasure, various methods have been proposed and exerted certain effects.

  For example, a carrier has been proposed in which a conductive material (carbon black) is present on the surface of the core material and no conductive material is present in the resin coating layer (see, for example, Patent Document 24). In addition, a carrier is proposed in which the coating resin layer has a carbon black concentration gradient in the thickness direction, the carbon black concentration decreases toward the surface of the coating resin layer, and there is no carbon black on the surface of the coating resin layer. (For example, see Patent Document 25). In addition, a two-layer coated carrier is proposed in which an inner coating resin layer containing conductive carbon is provided on the surface of core material particles, and a surface coating resin layer containing a white conductive material is further provided thereon. (For example, refer to Patent Document 26).

In general, as a resistance adjusting agent other than carbon black, for example, titanium oxide, zinc oxide and the like are known. However, a sufficient resistance reducing effect to replace carbon black cannot be obtained, and the problem has been solved. There is a need for improvement. For the purpose of imparting conductivity, a method for producing a powder in which the surface of white inorganic pigment particles is provided with a lower layer of tin dioxide and an upper layer of indium oxide containing tin dioxide (for example, Patent Document 27). reference). And the composition (for example, refer patent document 28) containing the same powder and resin is proposed.
JP-A-5-66600 JP-A-8-21655 JP-A-10-020552 JP 11-007156 A Japanese Patent Laid-Open No. 62-266550 JP 2005-49858 A JP-T-2003-515795 Special table 2006-500605 gazette JP-T-2006-503313 JP 2003-202708 A JP 58-108548 A JP 54-1555048 A JP 57-40267 A JP 58-108549 A JP 59-166968 A Japanese Patent Publication No. 1-19584 Japanese Examined Patent Publication No. 3-628 JP-A-6-202381 JP 2003-345070 A JP-A-5-273789 JP-A-9-160304 JP-A-8-6307 Japanese Patent No. 2683624 Japanese Unexamined Patent Publication No. 7-140723 JP-A-8-179570 JP-A-8-286429 Japanese Patent No. 2959927 Japanese Patent No. 2959928

  As described above, many techniques have been disclosed for toner and carrier. However, when used as an electrophotographic developer, the proposed carbon black-containing carrier is insufficient in durability and carrier adhesion suppressing effect. In other words, regarding the durability, there are problems such as spent (accumulation) of toner on the carrier surface, destabilization of the charge amount, and reduction of the coating layer due to coating resin scraping, and a decrease in resistance value. When used in a forming apparatus, a good image can be obtained initially, but there is a problem that the image quality of a copied image is lowered as the number of copies increases, and there is room for improvement.

  In addition, the electrophotographic developer corresponding to high speed and high image quality of recent image forming apparatuses is insufficient for resistance to high stress, and color smear in color copy has become a problem, and further improvement is necessary. There is. As a drastic measure against color stains, it is obvious that the most effective method is to eliminate carbon black that causes color stains. However, simply removing carbon black makes it difficult to adjust the electrical resistance of the carrier, as described above. In general, when a carrier having high electrical resistance is used as a developer, the image density of a large area of a copy image is very thin, and only the edge portion is expressed darkly, so that the so-called edge effect is sharply used. It becomes the image that was. In addition, when the image is a character or a thin line, the edge effect produces a clear image, but when the image is halftone, the image is very poorly reproducible. In the above-mentioned Patent Documents 24 to 28, a carrier not containing carbon black is proposed, but it cannot be said that the carrier has sufficient performance as a conventional carbon black-containing carrier.

  As can be seen from the above patent documents, as a two-component electrophotographic developer combining a toner and a carrier, the charge stability of the carrier as described above, the low-temperature fixability of the toner, and the edge of the image during image formation There has not yet been proposed an electrophotographic developer that is excellent in overall performance in consideration of suppression of effects and that exhibits stable performance even in long-term image formation.

  The present invention has been made in view of the above-described prior art, and is an electrophotographic developer capable of forming a fine image over a long period of time while suppressing both the charge stability and the low-temperature fixability and suppressing the edge effect. An object is to provide an image forming method, a process cartridge, and an image forming apparatus using the electrophotographic developer.

The inventors of the present invention completed the following invention.
The present invention is an electrophotographic developer comprising a toner and a carrier, wherein the toner contains a resin, a colorant, and a layered inorganic mineral in which at least part of interlayer ions is modified with organic ions, and at least The average circularity formed by dispersing and / or emulsifying the oil phase and / or the monomer phase containing the toner composition and / or toner composition precursor in an aqueous medium is 0.925 to 0.970. A negatively chargeable toner, wherein the carrier is an electrophotographic developer wherein the surface of the core is coated with a coating layer containing a binder resin, an ionic liquid, and inorganic fine particles.

In a preferred aspect of the present invention, the ratio (W) of the inorganic fine particles to the core material is within a range where the coverage (C) by the inorganic fine particles to the core material represented by the following formula satisfies 50% or more,
Coverage (C) = (Ds × ρs × W) / (4 × Df × ρf) × 100
(However, Ds: Volume average particle diameter of core material, ρs: True specific gravity of core material, Df: Volume average particle diameter of inorganic fine particles, ρf: True specific gravity of inorganic fine particles)
The electrophotographic developer, wherein the ratio (Df / h) of the volume average particle diameter (Df) of the inorganic fine particles to the film thickness (h) of the coating layer is 0.5 to 1.5. is there.

A preferable aspect of the present invention is the electrophotographic developer, wherein the carrier has a volume resistivity of 10 ¹⁰ Ω · cm to 10 ¹⁶ Ω · cm.

  A preferable aspect of the present invention is the electrophotographic developer, wherein the carrier has a volume average particle diameter of 20 μm to 65 μm.

  A preferable aspect of the present invention is the electrophotographic developer, wherein the binder resin contains at least a silicone resin.

  A preferable aspect of the present invention is the electrophotographic developer, wherein the binder resin is a mixed system of an acrylic resin and a silicone resin.

A preferable aspect of the present invention is the electrophotographic developer, wherein a magnetic moment in an applied magnetic field of 1 kOe (10 ³ / 4π · A / m) is 40 Am ² / kg to 90 Am ² / kg.

  The present invention includes a step of forming an electrostatic latent image on an image carrier, a step of developing the electrostatic latent image with a developer to form a visible image, and transferring the visible image to a recording member. An image forming method comprising: a step; and a step of fixing the visible image transferred to the recording member, wherein the developer is the electrophotographic developer according to the invention. It is.

  The present invention is:

The present invention relates to a photosensitive member that is detachably disposed on a main body of an image forming apparatus and forms an electrostatic latent image on a surface by exposure, and a charging unit that charges the surface of the photosensitive member to form an electrostatic latent image, and the photosensitive member A process cartridge comprising at least one of developing means for developing an electrostatic latent image formed on a surface with a developer, and cleaning means for removing dirt on the surface of the photoreceptor,
The developer is a process cartridge according to the electrophotographic developer of the present invention.

  The present invention includes at least a photosensitive member that forms an electrostatic latent image on the surface, a developing unit that converts the electrostatic latent image on the surface of the photosensitive member into a visible image using a developer, and a visible image on the surface of the photosensitive member. An image forming apparatus comprising a transfer means for transferring to a transfer material and a fixing means for fixing a visible image on the transfer material, wherein the developer is the electrophotographic developer of the invention. The image forming apparatus is characterized.

  According to the present invention, an electrophotographic developer capable of simultaneously forming charge stability and low-temperature fixability, suppressing an edge effect and forming a fine image over a long period of time, and image formation using the electrophotographic developer A method, a process cartridge, and an image forming apparatus can be provided.

  The best mode for carrying out the present invention will be described with reference to the drawings as necessary. Note that it is easy for a person skilled in the art to make other embodiments by changing or correcting the present invention within the scope of the claims, and these changes and modifications are included in the scope of the claims. The following description is an example of a preferred embodiment of the present invention, and does not limit the scope of the claims.

  The electrophotographic developer of the present invention is a two-component electrophotographic developer containing a toner and a carrier, and the toner is a layered inorganic material in which at least part of resin, colorant, and interlayer ions is modified with organic ions. Contains minerals. The toner has an average circularity of 0.925 formed by dispersing and / or emulsifying an oil phase and / or monomer phase containing at least a toner composition and / or a toner composition precursor in an aqueous medium and granulating. This is a negatively chargeable toner of ˜0.970. On the other hand, the carrier is a carrier in which the surface of the core material is coated with a coating layer containing a binder resin, an ionic liquid, and inorganic fine particles. The negatively chargeable toner may be expressed as “toner”, the electrophotographic developer carrier as “carrier”, and the electrophotographic developer as “developer”.

  It has been known that a toner having a stable quality can be obtained by adding a layered inorganic mineral modified with organic ions to the toner. However, in a two-component electrophotographic developer, if image formation is continued for a long time, the charge amount of the carrier tends to increase. However, in the electrophotographic developer of the present invention, an increase in charge amount is prevented by adding an ionic liquid to the carrier coating layer.

  As a result, the carrier in the electrophotographic developer of the present invention is capable of preventing toner spent accumulated on the carrier and suppressing the increase in charge, and having excellent durability and no fine edge effect. An electrophotographic developer that can be formed over a long period of time without causing any problems. An electrophotographic developer comprising this carrier and the above-described negatively chargeable toner can be suitably used as an oilless dry developer.

Hereinafter, the present invention will be described more specifically.
[Modified layered inorganic mineral]
The toner used in the developer of the present invention will be described in detail later. First, a layered inorganic mineral (modified layered inorganic mineral) contained in the toner, in which at least a part of ions between layers is modified with organic ions, will be described. A layered inorganic mineral refers to an inorganic mineral formed by superposing layers having a thickness of several μm, and modifying means introducing an organic ion into ions existing between the layers. As the layered inorganic mineral, for example, a smectite group (montmorillonite, saponite, etc.), a kaolin group (kaolinite, etc.), magadiite, and kanemite are known. Specific examples include layered inorganic substances described in JP-T-2006-500605, JP-T-2006-503313, and JP-A-2003-202708. Such a material structure is included in the intercalation in a broad sense.

  The hydrophilicity of the modified layered inorganic mineral varies depending on the modified layered structure. In other words, if the layered inorganic mineral is used in a toner that is dispersed and granulated in an aqueous medium without being modified, the layered inorganic mineral migrates into the aqueous medium, and the toner may be deformed (in a non-spherical shape). However, by using a modified layered inorganic mineral, the hydrophobicity becomes high and the toner is easily deformed at the time of granulation, and it is dispersed and refined to sufficiently exhibit the charge adjusting function. That is, such a modified inorganic mineral makes the particles finer at the time of production of the toner and makes the shape of the particles irregular, and it is particularly present in the surface portion of the toner particles to perform a charge control function and contribute to low-temperature fixing. . At this time, the content of the modified layered inorganic mineral in the toner material is preferably 0.05 to 5% by mass.

  The modified layered inorganic mineral used in the present invention is preferably one having a smectite basic crystal structure modified with an organic cation. In addition, a metal anion can be introduced by substituting a part of the divalent metal of the layered inorganic mineral with a trivalent metal. However, when the metal anion is introduced, the hydrophilic property is high, so at least a part of the metal anion is used. A layered inorganic compound in which is modified with an organic anion is desirable.

Examples of the organic ion modifier for the layered inorganic mineral in the modified layered inorganic mineral include quaternary alkylammonium salts, phosphonium salts, imidazolium salts and the like, and among them, quaternary alkylammonium salts are desirable. Examples of the quaternary alkylammonium include trimethylstearylammonium, dimethylstearylbenzylammonium, dimethyloctadecylammonium, oleylbis (2-hydroxyethyl) methylammonium and the like. The organic ion modifier branched, unbranched or cyclic alkyl _(C 1 _{~C 44),} alkenyl _(C 1 _{~C 22),} alkoxy _(C 8 _{~C 32),} hydroxyalkyl _(C 2 _{~C 22)} , Sulfates, sulfonates, carboxylates or phosphates having ethylene oxide, propylene oxide and the like. A carboxylic acid having an ethylene oxide skeleton is desirable.

  The layered inorganic mineral has moderate hydrophobicity by modifying at least part of the ions in the layered inorganic mineral with organic ions, and the modified layered inorganic mineral contains the toner composition and / or the toner composition precursor. When contained in the oil phase, the oil phase develops a non-Newtonian viscosity, and the toner can be deformed. At this time, the content of the modified layered inorganic mineral in the toner material is preferably 0.05 to 5% by mass as described above.

  The modified layered inorganic mineral can be selected as appropriate, and examples thereof include montmorillonite, bentonite, hectorite, attapulgite, sepiolite, and mixtures thereof modified with organic ions. Among these, organically modified montmorillonite or bentonite is preferable because the viscosity can be easily adjusted without affecting the toner characteristics and the addition amount can be reduced.

  As commercial products of layered inorganic minerals in which at least some of the ions between layers are modified with an organic cation, Bentone 3, Bentone 38, Bentone 38V (above, manufactured by Leox), Thixogel VP (manufactured by United catalyst), Kraton 34, Quatium 18 bentonite such as Clayton 40, Clayton XL (above, Southern Clay), etc .; Bentone 27 (made by Leox), Thixogel LG (made by United catalyst), Clayton AF, Clayton APA (above, made by Southern Clay), etc. Stearalkonium bentonite; quaternium 18 / benzalkonium bentonite such as Clayton HT and Clayton PS (manufactured by Southern Clay). Particularly preferable modified layered inorganic minerals include Clayton AF and Clayton APA.

  On the other hand, as a layered inorganic mineral in which at least some of the ions between layers are modified with an organic anion, DHT-4A (manufactured by Kyowa Chemical Industry Co., Ltd.) is modified with an organic anion represented by the following general formula (1). preferable. Examples of the following general formula (1) include Hytenol 330T (manufactured by Daiichi Kogyo Seiyaku Co., Ltd.).

_{R 1 (OR 2) n OSO} 3 M ... formula (1)
[Wherein, R ₁ represents an alkyl group having 13 carbon atoms, and R ₂ represents an alkylene group having 2 to 6 carbon atoms. n represents an integer of 2 to 10, and M represents a monovalent metal element]
By using the modified layered inorganic mineral having moderate hydrophobicity as described above, the oil phase containing the toner composition and / or the toner composition precursor is non-new in the production process of the toner containing the modified layered inorganic mineral. It has a Tonian viscosity and can deform the toner during toner formation.

[Career]
On the other hand, in the case of a two-component developer of toner and carrier, the mechanism of the toner containing a modified layered inorganic mineral is unknown, but there is a problem that the charging performance of the carrier over time may change. That is, the charge amount (charging) tends to increase with the toner consumption amount. This is considered to be caused by the accumulation of the toner component on the carrier surface, that is, spent, but the details of the mechanism by which the charge increases are unclear.

  If the spent toner component does not contain the modified layered inorganic mineral, the charge amount generally decreases, but the toner containing the modified layered inorganic mineral increases the charge amount. In a chart with a small image area (toner adhesion area) such as a sentence, the charge amount hardly changes, but in a chart with a large image area (toner adhesion area) such as a photograph or a poster image, the charge amount increases. A chart with a large image area consumes a large amount of toner, and the charge amount increases with the toner consumption amount.

  That is, it is necessary to remove spent matter accumulated on the carrier surface, and for the purpose of achieving this, the carrier in the present invention has a coating layer containing a binder resin and inorganic fine particles on the carrier core material, By providing irregularities on the surface of the carrier with fine particles contained in the carrier coating layer, spents are removed by self-polishing of the carriers. Further, an ionic liquid is contained in the coating layer for the purpose of suppressing the charge rise without being removed. By containing the ionic liquid, a charging leakage effect is obtained, and an increase in charging is suppressed.

  Examples of the inorganic fine particles include inorganic fine particles such as carbon black, titanium oxide, zinc oxide, indium oxide, aluminum oxide, tin oxide-antimony oxide, and tin oxide-indium oxide. If the inorganic fine particles are mixed in the toner due to the shaving of the coating layer, if the inorganic fine particles are colorless or other than white, the color image may be stained. Carbon black, indium oxide, and the like have a charging leakage effect, but it is necessary to pay attention to the problem of color stains.

  Zinc oxide and titanium oxide are white, but they have little charging leakage effect like carbon black and must be added in a large amount to the coating layer. When a large amount of inorganic fine particles are added, there is a problem that the inorganic fine particles are unevenly distributed in the carrier coating layer. When the unevenly distributed portions of the inorganic fine particles are exposed due to the scraping of the coating layer, an electrical leak point starts from that portion, and a local decrease in resistance value occurs. Due to the decrease in resistance value, carrier adhesion to the image area may occur, resulting in an abnormal image such as white spots.

  The ionic liquid is a liquid, and is easily finely dispersed with the coating resin when the coating layer liquid is formed. As a result, the ionic liquid is present in a finely dispersed state in the carrier coating layer, so that a local decrease in resistance value does not occur. In addition, since the ionic liquid is colorless to cloudy, even if the coating layer is scraped and mixed into the toner, color stains do not occur. Thus, by including an ionic liquid in the coating layer, the present invention has a remarkable charge leakage effect. The ionic liquid used in the present invention has general physical properties as an ionic liquid, that is, a liquid state in a wide temperature range of about −100 ° C. to 200 ° C., a high ionic conductivity, and a non-volatile property. Any material can be used as long as it is not flammable or flammable and has thermal stability.

However, in the present invention, it is preferable not to decompose in the temperature range generally used in the electrophotographic developer production process (resin thermosetting and solvent removal), that is, at least in the temperature range of 100 to 300 ° C. The ionic conductivity of the ionic liquid is not particularly limited, but is preferably 1.0 × 10 ³ (s / cm) or more within a temperature range of 10 to 30 ° C. If it is less than 1.0 × 10 ³ (s / cm), a charging leakage effect cannot be expected. When the charge rises, abnormal images such as carrier adhesion (edge carrier adhesion) to the non-image area, white spots, and insufficient image density occur.

  The specific composition of the ionic liquid used in the present invention is not particularly limited as long as it has physical properties as a general ionic liquid. It is preferable that physical properties such as ion conduction characteristics are more suitable. In the present invention, as a method for measuring the ionic conductivity of the ionic liquid, if a measurement is performed at a frequency of 10 kHz and 25 ° C. using a closed conductivity measuring cell and an AC impedance meter (CM-40S, manufactured by Toa Denki Kogyo). Good.

Examples of the ionic liquid include ammonium salts, imidazolium derivatives, pyridinium, phosphonium, and the like as organic cationium salts, and BF ₄ −, PF ₆ —, CF ₃ SO ₃ — (Tf: triflate), as organic acid anions. _{(CF 3 SO 2) 2 N-} (TFSI) , and the like. Of these, salts of ethylmethylimidazolium (EMI) and butylmethylimidazolium (BMI) are preferably used. In this invention, you may use the ionic substance containing the component melt | dissolved in an ionic liquid besides these.

  As the ionic liquid, it is preferable to use the following pyridinium-based (chemical formula 1), imidazolium-based (chemical formula 2), alicyclic amine-based (chemical formula 3), or aliphatic amine-based (chemical formula 4) materials.

（式中のＲ、Ｒ'は同一でも異なっていてもよく、それぞれ水素元素、炭素数１〜８の脂肪族炭化水素残基、炭素数５〜７のシクロアルキル基又はフェニル基を示す。）

(R and R ′ in the formula may be the same or different and each represents a hydrogen element, an aliphatic hydrocarbon residue having 1 to 8 carbon atoms, a cycloalkyl group having 5 to 7 carbon atoms, or a phenyl group.)

（式中のＲ、Ｒ'は同一でも異なっていてもよく、それぞれ水素元素、炭素数１〜８の脂肪族炭化水素残基、炭素数５〜７のシクロアルキル基又はフェニル基を示す。）

(R and R ′ in the formula may be the same or different and each represents a hydrogen element, an aliphatic hydrocarbon residue having 1 to 8 carbon atoms, a cycloalkyl group having 5 to 7 carbon atoms, or a phenyl group.)

（式中のＲ、Ｒ'は同一でも異なっていてもよく、それぞれ水素元素、炭素数１〜８の脂肪族炭化水素残基、炭素数５〜７のシクロアルキル基又はフェニル基を示す。）

(R and R ′ in the formula may be the same or different and each represents a hydrogen element, an aliphatic hydrocarbon residue having 1 to 8 carbon atoms, a cycloalkyl group having 5 to 7 carbon atoms, or a phenyl group.)

（式中のＲ、Ｒ'、Ｒ''、Ｒ'''は同一でも異なっていてもよく、それぞれ水素元素、炭素数１〜８の脂肪族炭化水素残基、炭素数５〜７のシクロアルキル基又はフェニル基を示す。）
イオン性液体の市販品としては、広栄化学工業社製 ピリジニム系イオン性液体としてＩＬ−Ｐ１１、ＩＬ−Ｐ１４や、イミダゾリウム系イオン性液体としてＩＬ−ＩＭ１や、脂環式アミン系イオン性液体としてＩＬ−Ｃ１、ＩＬ−Ｃ３、ＩＬ−Ｃ５、および脂肪族アミン系イオン性液体としてＩＬ−Ａ１、ＩＬ−Ａ２、ＩＬ−Ａ３、ＩＬ−Ａ４、ＩＬ−Ａ５（以上、全て広栄化学工業社製）などを挙げることができる。

(In the formula, R, R ′, R ″, and R ′ ″ may be the same or different, and each is a hydrogen element, an aliphatic hydrocarbon residue having 1 to 8 carbon atoms, or a cyclohexane having 5 to 7 carbon atoms. Represents an alkyl group or a phenyl group.)
Examples of commercially available ionic liquids include IL-P11 and IL-P14 as pyridinium ionic liquids manufactured by Guangei Chemical Industry Co., Ltd., IL-IM1 as imidazolium ionic liquids, and alicyclic amine ionic liquids. IL-C1, IL-C3, IL-C5, and IL-A1, IL-A2, IL-A3, IL-A4, and IL-A5 as aliphatic amine-based ionic liquids (all manufactured by Koei Chemical Co., Ltd.) And so on.

  As described above, the carrier used in the electrophotographic developer of the present invention has a coating layer containing a binder resin and conductive fine particles on a carrier core material. The carrier core material in the present invention (hereinafter sometimes abbreviated as “core material”) is known as a two-component carrier, for example, ferrite, Cu—Zn ferrite, Mn ferrite, Nmmg ferrite, Nmmg. -Sr ferrite, magnetite, iron, nickel, etc. may be appropriately selected according to the use and purpose of use of the carrier and is not limited to the exemplified materials.

The inorganic fine particles contained in the carrier coating layer preferably have a value of 50% or more when expressed by the coverage (C) shown in the following formula (1) with respect to the carrier core material.
Coverage ratio = (Ds × ρs × W) / (4 × Df × ρf) × 100 (1)
(Ds: carrier core material volume average particle diameter, ρs: carrier core material true specific gravity, W: ratio of inorganic fine particles to carrier core material, Df: volume average particle diameter of inorganic fine particles, ρf: true specific gravity of inorganic fine particles)
By doing so, irregularities are formed on the carrier surface, and agitation for frictionally charging the developer reduces the contact with a strong impact on the binder resin due to friction with the toner or friction between the carriers. be able to. As a result, it is possible to suppress toner spent on the carrier.

  The coverage (C) is calculated as follows. The true specific gravity ρf and the carrier core true specific gravity ρs of the inorganic fine particles are measured using a dry automatic bulk density meter Accupic 1330 (manufactured by Shimadzu Corporation). The carrier core particle size Ds (volume average particle size, unless otherwise specified, the particle size of the carrier core material and inorganic fine particles represents the volume average particle size) is a microtrack particle size analyzer (manufactured by Nikkiso Co., Ltd.) The SRA type is used for measurement. Use the one set in the range of 0.7μm or more and 125μm or less. Also, methanol is used for the dispersion, and the refractive index is set to 1.33, and the refractive indexes of the carrier and the core material are set to 2.42.

The particle diameter Df of the inorganic fine particles is determined by measuring the volume average particle diameter with an automatic particle size distribution analyzer CAPA-700 (manufactured by Horiba Seisakusho). As a pretreatment for measurement, 30 ml of aminosilane (SH6020: manufactured by Toray Dow Corning Silicon) and 300 ml of a toluene solution are placed in a juicer mixer. Add 6.0 g of sample, set mixer rotation speed to low and disperse for 3 minutes. An appropriate amount of the dispersion is added to 500 ml of a toluene solution prepared in advance in a 1000 ml beaker and diluted. The diluting solution is continuously stirred with a homogenizer. This diluted solution is measured with an ultracentrifugal automatic particle size distribution analyzer CAPA-700.
[Measurement condition]
Rotation speed: 2000rpm
Maximum particle size: 2.0 μm
Minimum particle size: 0.1 μm
Particle size interval: 0.1 μm
Dispersion medium viscosity: 0.59 mPa · s
Dispersion medium density: 0.87 g / cm ³
Particle density: As the density of inorganic fine particles, a true specific gravity value measured using a dry automatic bulk density meter Accupic 1330 (manufactured by Shimadzu Corporation) is used.

  In the above formula (1), when the coverage (C) is less than 50%, the probability that the surface of the carrier core material is exposed due to film scraping over time is increased, and the resistance is locally reduced. There is a tendency that a carrier having a non-existent state develops in a solid image and white spots occur in the image. In particular, the tendency is large at less than 40%.

Furthermore, as shown in FIG. 1, the ratio (Df / h) between the particle size (Df) of the inorganic fine particles contained in the carrier coating layer and the coating layer thickness (h) is 0.5 to 1.5. As a result, the improvement effect is remarkable. That is, when the ratio (Df / h) of the particle diameter (Df) to the coating layer thickness (h) is 0.5 to 1.5, there are those having a larger particle diameter than the coating film. Since the particles are convex, contact with a strong impact on the binder resin can be reduced in friction with the toner or friction between the carriers by stirring for tribocharging the developer. In FIG. 1, D represents the particle size of each inorganic fine particle, and the above Df is the volume average particle size of the inorganic fine particle. H _{1 to} h ₄ represent film thicknesses at the respective positions of the coating layer, and the above h represents the average coating layer film thickness.

  As a result, it is possible to suppress film scraping of the binder resin, which is a place where charging occurs. Further, as shown in FIG. 1, since there are many particles that are convex on the carrier surface as compared to the coating film, the cleaning effect of efficiently scraping off the spent component of the toner adhering to the carrier surface due to frictional contact between the carriers. In addition, toner spent can be prevented.

  When [Df / h] is less than 0.5, the inorganic fine particles tend to be buried in the binder resin, which is not preferable because the above effect is reduced. Particularly, when [Df / h] is less than 0.4, the effect is remarkably lowered, which is not preferable. When [Df / h] exceeds 1.5, the contact area between the inorganic fine particles and the binder resin is small, so that a sufficient binding force cannot be obtained and the inorganic fine particles are easily detached, which is not preferable. When the inorganic fine particles are detached from the carrier, the resistance is lowered, which is not preferable.

  FIG. 1 is a schematic diagram conceptually showing the relationship between the particle diameter (Df) of conductive fine particles and the coating layer thickness (h) in the coating layer of the carrier for an electrophotographic developer of the present invention. The thickness h of the coating layer of the carrier is obtained from an average value obtained by observing the cross section of the carrier using a transmission electron microscope (TEM), measuring the thickness of the resin portion of the coating layer covering the carrier surface. Specifically, only the thickness of the resin part existing between the surface of the carrier core material and the particles is measured. The thickness of the resin part existing between the particles and the thickness of the resin part on the inorganic fine particles are not included in the measurement. The average of arbitrary 50 point measurements in the carrier cross section is obtained and defined as the thickness h (μm). The particle diameter (Df) of the inorganic fine particles is measured with an ultracentrifugal automatic particle size distribution analyzer CAPA-700 in the same manner as the particle diameter measuring method of the inorganic fine particles described above.

Next, the resistance value (volume resistivity) of the carrier for the electrophotographic developer of the present invention is preferably 10 ¹⁰ to 10 ¹⁶ Ω · cm. Within this range, it can be adjusted as necessary. In an image forming system that requires high image quality such as a color image, it is essential to adjust the resistance value of the carrier. When the resistance value is less than 10 ¹⁰ Ω · cm, carrier adhesion occurs in the non-image area, which is not preferable. On the other hand, when the volume resistivity exceeds 10 ¹⁶ Ω · cm, the edge effect deteriorates to an unacceptable level. In practice, when the value falls below the measurable lower limit of the high resist meter, the volume resistivity value is practically not obtained and is treated as a breakdown.

  The resistance value (volume specific resistance) of the carrier may be measured by a carrier resistance measuring device shown in the schematic diagram of FIG. The resistance value is such that a cell 31 made of a fluororesin container containing an electrode 32a and an electrode 32b having a distance between electrodes of 2 mm and a surface area of 2 × 4 cm is filled with a carrier 33, and manufactured by Sankyo Piotech Co., Ltd .: Tapping machine PTM-1 type The tapping operation is performed for 1 minute at a tapping speed of 30 times / min. A DC voltage of 1000 V is applied between both electrodes, DC resistance is measured by a high resistance meter 4329A (4329A + LJK5HVLVWDQFH0HWHU; manufactured by Yokogawa Hewlett-Packard Co., Ltd.), electric resistivity RΩ · cm is obtained, and LogR is calculated.

  The volume average particle size of the carrier in the present invention is preferably 20 μm to 65 μm. When the volume average particle size is 20 μm or more and 65 μm or less, the effect of improving the carrier adhesion and the image quality is remarkable. This is not preferable when the volume average particle size is less than 20 μm, since problems such as carrier adhesion occur due to a decrease in the uniformity of the particles and a lack of sufficient technology on the machine side. On the other hand, if it exceeds 65 μm, the reproducibility of image details is poor and a fine image cannot be obtained.

  The volume average particle diameter of the carrier can be measured using an SRA type of a Microtrac particle size analyzer (manufactured by Nikkiso Co., Ltd.). What was performed by the range setting of 0.7 micrometer or more and 125 micrometers or less is used. Further, methanol is used for the dispersion, and the refractive index is set to 1.33, and the refractive indexes of the carrier and the core material are set to 2.42.

  It is preferable to contain at least a silicone resin as a binder resin for the carrier. The improvement effect is remarkable because the binder resin of the carrier is at least a silicone resin. This is because the silicone resin has a low surface energy, so that it is difficult for the toner component to be spent and the film is scraped, so that it is difficult to accumulate the spent component.

  The silicone resin in the present invention refers to all generally known silicone resins, including straight silicones composed only of organosilosan bonds, silicone resins modified with alkyd, polyester, epoxy, acrylic, urethane, etc. However, it is not limited to this. For example, taking a commercial product as an example, examples of the straight silicone resin include KR271, KR255, and KR152 manufactured by Shin-Etsu Chemical, SR2400, SR2406, and SR2410 manufactured by Toray Dow Corning Silicon. In this case, it is possible to use the silicone resin alone, but it is also possible to simultaneously use other components that undergo a crosslinking reaction, charge amount adjusting components, and the like. Further, as modified silicone resins, KR206 (alkyd modified), KR5208 (acrylic modified), ES1001N (epoxy modified), KR305 (urethane modified) manufactured by Shin-Etsu Chemical, SR2115 (epoxy modified) manufactured by Toray Dow Corning Silicon Co., Ltd. , SR2110 (alkyd modified) and the like.

  Furthermore, a mixed system of an acrylic resin and a silicone resin can be used as the binder resin for the carrier. By using the acrylic resin in combination with the silicone resin, the improvement effect such as the adhesiveness of the coating layer becomes remarkable. In other words, since acrylic resin has strong adhesiveness and low brittleness, it has very excellent properties in terms of wear resistance, it is difficult to cause deterioration such as coating film scraping and film peeling, and the coating layer must be maintained stably. In addition, the particles contained in the coating layer such as conductive fine particles can be firmly held due to the strong adhesiveness. In particular, a powerful effect can be exerted in holding fine particles having a particle size larger than the coating layer thickness.

  The acrylic resin in the present invention refers to all resins having an acrylic component and is not particularly limited. Moreover, it is possible to use the acrylic resin alone, and it is also possible to simultaneously use at least one other component that undergoes a crosslinking reaction with the acrylic resin. Examples of other components that undergo a crosslinking reaction include amino resins and acidic catalysts, but are not limited thereto. Examples of the amino resin include guanamine and melamine resin, but are not limited thereto. In addition, as the acidic catalyst, any having a catalytic action can be used. For example, it has a reactive group such as a fully alkylated type, a methylol group type, an imino group type, and a methylol / imino group type, but is not limited thereto.

  As described above, acrylic resin has a very excellent property of abrasion resistance due to its strong adhesiveness and low brittleness, but on the other hand, its surface energy is high, so in combination with easily spent toner, Problems such as a decrease in charge amount due to spent (accumulation) may occur. In this case, this problem can be solved by using together a silicone resin that has an effect that it is difficult to spend the toner component due to the low surface energy and the accumulation of the spent component is difficult to progress due to film abrasion. However, since the silicone resin has weak adhesiveness and high brittleness, it also has a weak point that it has poor wear resistance. Therefore, it is important to obtain a good balance between the properties of these two resins. It is possible to obtain a coating film having wear characteristics.

The carrier in the present invention preferably has a magnetic moment in the applied magnetic field of 1 kOe (10 ³ / 4π · A / m) of 40 Am ² / kg or more and 90 Am ² / kg or less. Hereinafter, the strength of the applied magnetic field may be expressed by Oe (Oersted). Note that 1000 Oe (1 kOe) corresponds to 10 ³ / 4π · A / m.

By setting the magnetic moment within the above range, the retention force between the carrier particles is appropriately maintained, so that the dispersion (mixing) of the toner into the carrier or the developer is quickly improved, but the magnetic moment at 1 kOe is 40 Am ^2. If it is less than / kg, carrier adhesion occurs due to insufficient magnetic moment, which is not preferable. On the other hand, when the magnetic moment at 1 kOe exceeds 90 Am ² / kg, the ears of the developer formed at the time of development become too hard, so that the reproducibility of image details is poor and a fine image cannot be obtained.

  The magnetic moment can be measured as follows. Using a BH tracer (BHU-60 / manufactured by Riken Denshi Co., Ltd.), 1.0 g of carrier core particles are packed in a cylindrical cell (inner diameter 7 mm, height 10 mm) and set in an apparatus. The magnetic field is gradually increased to 3 kOe, then gradually decreased to zero, and then the opposite magnetic field is gradually increased to 3 kOe. Further, after gradually reducing the magnetic field to zero, a magnetic field is applied in the same direction as the first. In this way, the BH curve is illustrated, and a magnetic moment of 1 kOe is calculated from the figure.

[toner]
Next, the toner used for the developer of the present invention will be described in detail.
The toner used in the developer of the present invention contains a resin, a colorant, and a layered inorganic mineral obtained by modifying at least some of the ions between layers with organic ions, and at least a toner composition and / or a toner composition precursor. The oily phase and / or monomer phase containing is dispersed and / or emulsified in an aqueous medium and granulated with an average circularity of 0.925 to 0.970 and negatively charged. The toner is highly reliable in cleaning, excellent in low-temperature fixability, and excellent in fine dot reproducibility, so that high-quality image quality can be stably obtained.

  The average circularity of the toner is preferably from 0.925 to 0.970, more preferably from 0.945 to 0965. The circularity is a value obtained by dividing the circumference of a circle having an area equal to the projected area of the sample by the circumference of the sample. The content of particles having a circularity of less than 0.925 in the toner is preferably 15% or less. If the average circularity is less than 0.925, satisfactory transferability and a high-quality image free from dust may not be obtained. If it exceeds 0.970, an image forming apparatus employing blade cleaning or the like may not be used. In addition, poor cleaning of the photosensitive member and the transfer belt may occur, and stains on the image may occur. For example, when forming an image with a high image area ratio, such as a photographic image, toner that has formed an untransferred image due to poor paper feed or the like accumulates on the photoconductor, causing image smudges or touching the photoconductor The charging roller or the like to be charged may be contaminated and the original charging ability may not be exhibited.

  The average circularity can be measured by an optical detection band method in which a suspension containing toner is passed through an imaging unit detection band on a flat plate, a particle image is optically detected by a CCD camera, and analyzed. It can be measured using a flow type particle image analyzer FPIA-2100 (manufactured by Sysmex Corporation).

  In the toner constituting the electrophotographic developer of the present invention, the ratio (Dv / Dn) of the volume average particle diameter (Dv) to the number average particle diameter (Dn) is 1.00 to 1.30. Preferably, such a range makes it possible to obtain high resolution and high image quality. Furthermore, in the case of a two-component developer, even if the toner supply and use is repeated for a long period of time, the variation in the particle diameter of the toner in the developer is reduced, and even in the long-term agitation in the developing device, it is good and stable. Developability is possible. More preferably, Dv / Dn is in the range of 1.00 to 1.20, and a better image can be obtained. If Dv / Dn exceeds 1.30, the variation in the particle size of the toner particles is large, causing variations in the behavior of the toner during development and the like, and the reproducibility of minute dots is impaired. High-quality images cannot be obtained.

  In the toner of the present invention, the volume average particle diameter Dv is preferably 3.0 to 7.0 μm. In general, it is said that the smaller the particle size of the toner, the more advantageous it is to obtain a high-resolution and high-quality image, but it is disadvantageous for transferability and cleaning properties. is there. Further, when the volume average particle diameter is smaller than the above range, in the case of a two-component developer, the toner is fused to the surface of the carrier during a long period of stirring in the developing device, and the charging ability of the carrier is lowered, and as a one-component developer. When used, toner filming on the developing roller and toner fusion to a member such as a blade for thinning the toner are likely to occur.

  In addition, these phenomena are greatly related to the content of fine powder. In particular, when the particle size of 2 μm or less exceeds 20%, it becomes an obstacle to the adhesion to the carrier and the high level of charging stability. Conversely, when the toner particle size is larger than the above range, it becomes difficult to obtain a high-resolution and high-quality image, and the toner particle size when the balance of the toner in the developer is performed. In many cases, fluctuations of It was also clarified that the same applies when the volume average particle diameter / number average particle diameter is larger than 1.30.

  Next, the relationship between toner shape and transferability will be described. When using a full-color copier that transfers images with multicolor development, the amount of toner on the photoconductor increases compared to the case of one-color black toner used in black-and-white copiers. Therefore, it is difficult to improve transfer efficiency. Further, in the case of using an ordinary irregularly shaped toner, a shearing force between the photosensitive member and the cleaning member, between the intermediate transfer member and the cleaning member, and / or between the photosensitive member and the intermediate transfer member, Due to the rubbing force, toner fusing or filming occurs on the surface of the photoreceptor or the intermediate transfer member, and transfer efficiency tends to deteriorate. When generating a full-color image, it is difficult to transfer the four-color toner images uniformly. Furthermore, when an intermediate transfer member is used, problems are likely to occur in terms of color unevenness and color balance, and high-quality full-color images are stabilized. Output is not easy.

  As described above, a toner having a small particle size and a uniform particle size has difficulty in cleaning properties. Therefore, it is preferable that 20-80% of the toner particles have a circularity of 0.950 or less. That is, from the viewpoint of the balance between blade cleaning and transfer efficiency, particles having a toner circularity of 0.950 or less are 20 to 80% of the total toner particles, thereby achieving both cleaning and transferability. Cleaning and transferability are greatly related to the material of the blade and how to apply the blade, and transfer also varies depending on the process conditions, so that the design according to the process can be performed within the above range.

  However, if the toner circularity is 0.950 or less than 20% of all toner particles, cleaning with a blade becomes difficult. On the other hand, when the particles having a circularity of 0.950 or less exceed 80% of the total toner particles, the above-described transferability is deteriorated. This phenomenon is caused by excessively deformed toner shape, so that toner movement during transfer (photosensitive member surface to transfer paper, photosensitive member surface to intermediate transfer belt, first intermediate transfer belt to second intermediate transfer belt) , Etc.) are not smooth, and the toner particles vary in behavior, so that uniform and high transfer efficiency cannot be obtained. In addition, unstable charging and brittleness of particles begin to appear. Furthermore, it becomes a pulverization phenomenon in the developer, which causes a decrease in the durability of the developer.

(Measurement of toner particle size, circularity, etc.)
Hereafter, the measuring method regarding the property of the toner of this invention is shown. The particle ratio of 2 μm or less, the circularity and the average circularity of the toner in the present invention can be measured by a flow type particle image analyzer FPIA-2000 (manufactured by Toa Medical Electronics Co., Ltd.). As a specific measuring method, 0.1 to 0.5 ml of a surfactant, preferably alkyl benzene sulfonate, is added as a dispersant to 100 to 150 ml of water from which impure solids have been removed in advance, and a measurement sample is further added. About 0.1 to 0.5 g. The suspension in which the sample is dispersed is obtained by performing dispersion treatment with an ultrasonic disperser for about 1 to 3 minutes, and measuring the shape and distribution of the toner with the above apparatus at a dispersion concentration of 3000 to 10,000 / μl. .

  The toner particle diameter is determined by a car Coulter counter method. Examples of the measuring device for the particle size distribution of the toner particles include Coulter Counter TA-II and Coulter Multisizer II (both manufactured by Coulter). In the present invention, measurement may be performed by using a Coulter counter TA-II type, connected to an interface (Nikka Giken) that outputs a number distribution and volume distribution, and a PC 9801 personal computer (manufactured by NEC).

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

  As channels, 2.00 to less than 2.52 μm; 2.52 to less than 3.17 μm; 3.17 to less than 4.00 μm; 4.00 to less than 5.04 μm; 5.04 to less than 6.35 μm; 6 Less than 35 to 8.00 μm; less than 8.00 to less than 10.08 μm; less than 10.08 to less than 12.70 μm; less than 12.70 to less than 16.00 μm; less than 16.00 to less than 20.20 μm; Uses 13 channels of less than 40 μm; 25.40 to less than 32.00 μm; 32.00 to less than 40.30 μm, and targets particles having a particle size of 2.00 μm to less than 40.30 μm. The volume-based volume average particle diameter (Dv) obtained from the volume distribution according to the present invention and the number average particle diameter (Dn) obtained from the number distribution and the ratio Dv / Dn are obtained.

(Binder resin)
In particular, the toner in the present invention is preferably granulated by dispersing and / or emulsifying an oil phase and / or monomer phase containing at least a toner composition and / or a toner composition precursor in an aqueous medium. As the resin (binder resin for toner), a polyester resin as described in detail later is preferable.

  According to the study of the present invention, in order to effectively exhibit low-temperature fixability while maintaining heat-resistant storage stability and to impart offset resistance after modification with a prepolymer, the acidic group-containing polyester resin THF The mass average molecular weight of the soluble component is preferably 1,000 to 30,000. This is because when the amount is less than 1,000, the oligomer component increases, the heat-resistant storage stability is deteriorated, and when it exceeds 30,000, the modification with the prepolymer is insufficient due to steric hindrance and the offset resistance is deteriorated.

The molecular weight of the polyester resin is measured by GPC (gel permeation chromatography) as follows. The column was stabilized in a heat chamber at 40 ° C., and THF as a solvent was passed through the column at this temperature at a flow rate of 1 ml / min. Is measured by injecting 50 to 200 μl. In measuring the molecular weight of the sample, the molecular weight distribution of the sample is calculated from the relationship between the logarithmic value of the prepared calibration curve and the number of counts using several types of monodisperse polystyrene standard samples. As a standard polystyrene sample for preparing a calibration curve, for example, Pressure Chemical Co. Or molecular weight made by Toyo Soda Industry Co., Ltd. is 6 × 10 ² , 2.1 × 10 ³ , 4 × 10 ³ , 1.75 × 10 ⁴ , 5.1 × 10 ⁴ , 1.1 × 10 ⁵ , 3.9. It is suitable to use x10 ⁵ , 8.6 × 10 ⁵ , 2 × 10 ⁶ , 4.48 × 10 ⁶ , and use at least about 10 standard polystyrene samples. An RI (refractive index) detector is used as the detector.

  By adjusting the acid value of the polyester resin, which is the first binder resin, to 1.0 to 50.0 (KOHmg / g), particle size control by adding a base compound, low temperature fixability, high temperature offset resistance, heat resistant storage The toner characteristics such as the property and the charging stability can be improved. That is, when the acid value exceeds 50.0 (KOHmg / g), the extension or crosslinking reaction of the modified polyester becomes insufficient, and the high-temperature offset resistance is affected, and when it is less than 1.0 (KOHmg / g) This is because a dispersion stabilizing effect due to the base compound during production cannot be obtained, and the elongation or cross-linking reaction of the modified polyester tends to proceed, resulting in a problem in production stability.

The acid value is measured according to the measurement method described in JIS K0070-1992 under the following conditions. For sample preparation, 0.5 g of polyester is added to 120 ml of THF and dissolved by stirring at room temperature (23 ° C.) for about 10 hours. Further, 30 ml of ethanol is added to prepare a sample solution. The measurement can be performed by measurement with the above apparatus, and specifically, the calculation is performed as follows. Titrate with a pre-standardized N / 10 caustic potash to alcohol solution, and determine the acid value from the consumption of the alcohol potash solution by the following calculation.
Acid value = KOH (ml) x N x 56.1 / sample mass (where N is a factor of N / 10 KOH)
In the case of measuring the acid value of a polyester resin suitably used as an example of the resin for the toner composition in the present invention, details of the measuring method are based on JIS K0070. That is, according to the following method. Note that THF is used as a solvent.
* The acid value is specifically determined by the following procedure.
Measuring device: Potential difference automatic complaint DL-53 Titrator (manufactured by METTLER TOLEDO)
Electrode used: DG113-SC (manufactured by METTLER TOLEDO)
Analysis software: LabX Light Version 1.00.000
Calibration of equipment: Use a mixed solvent of 120 ml of toluene and 30 ml of ethanol Measurement temperature: 23 ° C
*Measurement condition
Stir
SPEED [%] 25
Time [s] 15
EQP titration
Titrant / Sensor
Titrant CH3ONa
Concentration [mol / L] 0.1
Sensor DG115
Unit of measurement mV
Predispensing to volume
Volume [mL] 1.0
Wait time [s] 0
Titrant addition Dynamic
dE (set) [mV] 8.0
dV (min) [mL] 0.03
dV (max) [mL] 0.5
Measure mode Equilibrium controlled
dE [mV] 0.5
dt [s] 1.0
t (min) [s] 2.0
t (max) [s] 20.0
Recognition
Threshold 100.0
Steepest jump only No
Range No
Tendency None
Termination
at maximum volume [mL] 10.0
at potential No
at slope No
after number EQPs Yes
n = 1
comb. termination conditions No
Evaluation
Procedure Standard
Potential 1 No
Potential 2 No
Stop for reevaluation No.

  In the present invention, the heat-resistant storage performance of the polyester resin after modification, that is, the main component of the binder resin depends on the glass transition point of the polyester resin before modification, so the glass transition point of the polyester resin is 35 ° C. to 65 ° C. It is preferable to design to. That is, if it is less than 35 ° C., the heat-resistant storage stability is insufficient, and if it exceeds 65 ° C., it adversely affects low-temperature fixing.

  The glass transition point (Tg) is measured with a Rigaku THRMOFLEX TG8110 manufactured by Rigaku Corporation under a temperature increase rate of 10 ° C./min. A method for measuring Tg will be outlined. As an apparatus for measuring Tg, a TG-DSC system TAS-100 manufactured by Rigaku Corporation was used. First, about 10 mg of a sample is put in an aluminum sample container, placed on a holder unit, and set in an electric furnace. Next, after heating from room temperature to 150 ° C. at a rate of temperature increase of 10 ° C./min, the sample was allowed to stand at 150 ° C. for 10 min, the sample was cooled to room temperature and allowed to stand for 10 min, and the rate of temperature increase to 150 ° C. again under a nitrogen atmosphere. DSC measurement is performed by heating at / min. Tg is calculated from the contact point between the tangent line and the base line of the endothermic curve near Tg, using the analysis system in the TAS-100 system.

  The prepolymer that modifies the polyester resin is an important binder resin component for realizing low-temperature fixability and high-temperature offset resistance, and its mass average molecular weight is preferably 3,000 to 20,000. That is, if the mass average molecular weight is less than 3,000, it becomes difficult to control the reaction rate, and problems in production stability begin to occur. On the other hand, when the mass average molecular weight exceeds 20,000, sufficient modified polyester cannot be obtained and the offset resistance starts to be affected.

  It has been found that the toner acid value is a more important index than the binder resin acid value for low-temperature fixability and high-temperature offset resistance. The toner acid value of the present invention is derived from the terminal carboxyl group of the unmodified polyester. The unmodified polyester preferably has an acid value of 0.5 to 40.0 (KOHmg / g) in order to control low-temperature fixability (fixing lower limit temperature, hot offset occurrence temperature, etc.) as a toner. In other words, when the toner acid value exceeds 40.0 (KOHmg / g), the modified polyester is insufficiently stretched or cross-linked, affecting high-temperature offset resistance, and less than 0.5 (KOHmg / g). In this case, the dispersion stabilizing effect due to the base compound at the time of production cannot be obtained, and the extension or crosslinking reaction of the modified polyester tends to proceed, resulting in a problem in production stability.

  Specifically, the acid value is determined in accordance with the method for measuring the acid value of the polyester resin. When there is THF-insoluble matter, the acid value of the toner is a value when the acid value is measured using THF as a solvent. Measurement is performed under the following conditions in accordance with the measurement method described in JIS K0070-1992. Sample preparation: 0.5 g of toner (0.3 g for ethyl acetate-soluble component) was used in place of the polyester.

  The glass transition point of the toner used in the developer of the present invention is preferably 40 to 70 ° C. in order to obtain low temperature fixability, heat resistant storage stability and high durability. That is, when the glass transition point is less than 40 ° C., blocking in the developing machine and filming to the photoreceptor are liable to occur, and when it exceeds 70 ° C., the low-temperature fixability tends to deteriorate.

  The toner used in the developer of the present invention is a solution or dispersion formed by dissolving or dispersing a binder component composed of a modified polyester resin capable of reacting at least with active hydrogen and a toner composition composed of a colorant in an organic solvent. It is obtained by reacting with a crosslinking agent and / or an extender in a hydrogen medium containing a dispersant and removing the solvent from the resulting dispersion.

  Examples of the reactive modified polyester resin (RMPE) capable of reacting with active hydrogen include a polyester prepolymer (A) having an isocyanate group. Examples of the prepolymer (A) include a polycondensate of a polyol (PO) and a polycarboxylic acid (PC) and a polyester having active hydrogen further reacted with a polyisocyanate (PIC).

  Examples of the group containing active hydrogen in the polyester include a hydroxyl group (alcoholic hydrogen 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.

  An amine is used as a crosslinking agent for the reactive modified polyester resin, and a diisocyanate compound (diphenylmethane diisocyanate or the like) is used as an extender. The amines described in detail later act as a crosslinking agent and an extender for the modified polyester capable of reacting with active hydrogen.

  Modified polyester such as urea-modified polyester obtained by reacting the polyester prepolymer (A) having an isocyanate group with an amine (B) can easily adjust the molecular weight of the polymer component, and is a dry toner, particularly oilless low-temperature fixing. It is convenient to ensure the characteristics (wide releasability and fixability without a release oil application mechanism to the fixing heating medium). Particularly, a polyester prepolymer whose end is modified with urea can suppress adhesion to a heating medium for fixing while maintaining high fluidity and transparency in the fixing temperature range of the unmodified polyester resin itself.

  A preferred polyester prepolymer used in the present invention is a polyester having an active hydrogen group such as an acid group or a hydroxyl group at the terminal, and a functional group such as an isocyanate group that reacts with the active hydrogen. A modified polyester (MPE) such as urea-modified polyester can be derived from this prepolymer, but in the case of the present invention, a preferred modified polyester used as a binder resin is based on a polyester prepolymer (A) having an isocyanate group. , A urea-modified polyester obtained by reacting amines (B) as a crosslinking agent and / or an extender.

  The polyester prepolymer (A) having an isocyanate group is obtained by further reacting a polyester having an active hydrogen group, which is a polycondensate of a polyol (PO) and a polycarboxylic acid (PC), with a polyisocyanate (PIC). Can do.

  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 as described above. Among these, an alcoholic hydroxyl group is preferable.

  Examples of the polyol (PO) include a diol (DIO) and a trivalent or higher polyol (TO), and (DIO) alone or a mixture of (DIO) and a small amount of (TO) is preferable. Diol (DIO) includes alkylene glycol (ethylene glycol, 1,2-propylene glycol, 1,3-propylene glycol, 1,4-butanediol, 1,6-hexanediol, etc.); alkylene ether glycol (diethylene glycol, triethylene glycol, Ethylene glycol, dipropylene glycol, polyethylene glycol, polypropylene glycol, polytetramethylene ether glycol, etc.); alicyclic diols (1,4-cyclohexanedimethanol, hydrogenated bisphenol A, etc.); bisphenols (bisphenol A, bisphenol F, Bisphenol S, etc.); alkylene oxide (ethylene oxide, propylene oxide, butylene oxide, etc.) adduct of the above alicyclic diol; Alkylene oxide phenol compound (ethylene oxide, propylene oxide, butylene oxide, etc.), etc. adducts.

  Among them, preferred are alkylene glycols having 2 to 12 carbon atoms and alkylene oxide adducts of bisphenols, and particularly preferred are alkylene oxide adducts of bisphenols and alkylene glycols having 2 to 12 carbon atoms. It is a combined use. Examples of the trivalent or higher polyol (TO) include 3 to 8 or higher polyhydric aliphatic alcohols (glycerin, trimethylolethane, trimethylolpropane, pentaerythritol, sorbitol, etc.); trivalent or higher phenols (Tris) Phenol PA, phenol novolak, cresol novolak, etc.); alkylene oxide adducts of the above trivalent or more polyphenols.

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

  Dicarboxylic acids (DIC) 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, naphthalene) Dicarboxylic acid and the like). Of 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 (TC) include aromatic polycarboxylic acids having 9 to 20 carbon atoms (such as trimellitic acid and pyromellitic acid).

  In addition, as polycarboxylic acid (PC), you may make it react with a polyol (PO) using the above-mentioned acid anhydride or lower alkyl ester (Methyl ester, ethyl ester, isopropyl ester, etc.). The ratio of the polyol (PO) and the polycarboxylic acid (PC) is usually 2/1 to 1/1, preferably 1 as the equivalent ratio [OH] / [COOH] of the hydroxyl group [OH] and the carboxyl group [COOH]. 5/1 to 1/1, more preferably 1.3 / 1 to 1.02 / 1.

  As polyisocyanate (PIC), aliphatic polyisocyanate (tetramethylene diisocyanate, hexamethylene diisocyanate, 2,6-diisocyanatomethylcaproate, etc.); alicyclic polyisocyanate (isophorone diisocyanate, cyclohexylmethane diisocyanate, etc.); aromatic Diisocyanates (tolylene diisocyanate, diphenylmethane diisocyanate, etc.); araliphatic diisocyanates (α, α, α ′, α′-tetramethylxylylene diisocyanate, etc.); isocyanurates; polyisocyanates such as phenol derivatives, oximes, caprolactams, etc. And a combination of two or more of these.

  The ratio of the polyisocyanate (PIC) is usually 5/1 to 1/1, preferably 4 /, as an equivalent ratio [NCO] / [OH] of the isocyanate group [NCO] and the hydroxyl group [OH] of the polyester having a hydroxyl group. 1 to 1.2 / 1, more preferably 2.5 / 1 to 1.5 / 1.

  When [NCO] / [OH] exceeds 5, low-temperature fixability deteriorates. When the molar ratio of [NCO] is less than 1, when a modified polyester is used, the urea content in the ester becomes low and the hot offset resistance deteriorates.

  The content of the polyisocyanate (3) component in the prepolymer (A) having an isocyanate group at the terminal is usually 0.5 to 40% by mass, preferably 1 to 30% by mass, more preferably 2 to 20% by mass. It is. If it is less than 0.5% by mass, the hot offset resistance deteriorates, and it is disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability. On the other hand, if it exceeds 40% by mass, the low-temperature fixability deteriorates.

  The number of isocyanate groups contained per molecule in the prepolymer (A) having an isocyanate group is usually 1 or more, preferably 1.5 to 3 on average, more preferably 1.8 to 2.5 on average. It is. 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 amines (B), diamine (B1), trivalent or higher polyamine (B2), aminoalcohol (B3), aminomercaptan (B4), amino acid (B5), and amino acids B1-B5 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, diaminecyclohexane, 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 B1 to B5 blocked amino groups (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 mixture of B1 and a small amount of B2.

  Furthermore, if necessary, the molecular weight of the 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 ratio of amines (B) is the equivalent ratio [NCO] / [NHx] of isocyanate groups [NCO] in the prepolymer (A) having isocyanate groups and amino groups [NHx] in amines (B). The ratio is usually 1/2 to 2/1, preferably 1.5 / 1 to 1 / 1.5, more preferably 1.2 / 1 to 1 / 1.2. When [NCO] / [NHx] is more than 2 or less than 1/2, the molecular weight of the polyester is lowered and the hot offset resistance is deteriorated.

  In the present invention, the polyester-based resin (polyester) preferably used as the binder resin is urea-modified polyester (UMPE), but this polyester may contain a urethane bond together with a urea bond. The molar ratio of the urea bond content to 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.

Modified polyester such as urea-modified polyester (UMPE) is produced by a one-shot method or the like. The weight average molecular weight of the modified polyester such as urea-modified polyester (UMPE) is usually 10,000 or more, preferably 20,000 to 10,000,000, and more preferably 30,000 to 1,000,000. If it is less than 10,000, the hot offset resistance deteriorates. The number average molecular weight of the modified polyester such as urea-modified polyester is not particularly limited when the unmodified polyester (PE) described later is used, and may be a number average molecular weight that can be easily obtained to obtain the mass average molecular weight. In the case of a modified polyester such as UMPE alone, the number average molecular weight is usually 2000-15000, preferably 2000-10000, and more preferably 2000-8000. If it exceeds 15000, the low-temperature fixability and the gloss when used in a full-color device are deteriorated.

  In the present invention, the above modified polyester such as polyester modified with urea bond (UMPE) is not only used alone, but can also contain unmodified polyester (PE) as a binder resin component. . The combined use of PE improves low-temperature fixability and gloss when used in a full-color device, and is preferable to single use.

  Examples of PE include polycondensates of polyol PO and polycarboxylic acid PC similar to the polyester component of UMPE, and preferred ones are also the same as in UMPE.

  The mass average molecular weight (Mw) of PE is 10,000 to 300,000, preferably 14,000 to 200,000. Its Mn (number average molecular weight) is 1000 to 10000, preferably 1500 to 6000. For UMPE, not only unmodified polyesters but also those modified with chemical bonds other than urea bonds, such as those modified with urethane bonds, can be used in combination. UMPE and PE are preferably at least partially compatible with each other in terms of low-temperature fixability and hot offset resistance. Accordingly, the polyester component of UMPE and PE preferably have similar compositions.

  The mass ratio of UMPE to PE when PE is contained is usually 5/95 to 80/20, preferably 5/95 to 30/70, more preferably 5/95 to 25/75, and particularly preferably 7/93. ~ 20/80. If the mass ratio of UMPE is less than 5%, the hot offset resistance deteriorates, and it is disadvantageous in terms of both heat-resistant storage stability and low-temperature fixability.

  The hydroxyl value (mgKOH / g) of PE is preferably 5 or more, and the acid value (mgKOH / g) of PE is usually 1 to 30, preferably 5 to 20. By giving an acid value, it tends to be negatively charged, and further, the affinity between the paper and the toner is good when fixing to paper, and the low-temperature fixability is improved. However, when the acid value exceeds 30, there is a tendency to deteriorate with respect to the stability of charging, particularly environmental fluctuation. In the polymerization reaction, if the acid value is touched, it will cause blurring in the granulation process, making it difficult to control the emulsification.

(Measurement method of hydroxyl value)
The conditions of the measuring apparatus are the same as those in the above acid value measurement. Weigh accurately 0.5 g of sample into a 100 ml volumetric flask and add 5 ml of acetylating reagent correctly. Then, it is immersed in a bath at 100 ° C. ± 5 ° C. and heated. After 1-2 hours, the flask is removed from the bath, allowed to cool, water is added and shaken to decompose acetic anhydride. Further, in order to complete the decomposition, the flask is again heated in a bath for 10 minutes or more and allowed to cool, and then the wall of the flask is thoroughly washed with an organic solvent. This solution is subjected to potentiometric titration with an N / 2 potassium hydroxide ethyl alcohol solution using the electrode to determine the OH value (according to JISK0070-1966).

  In the present invention, the glass transition point (Tg) of the binder resin is usually 40 to 70 ° C, preferably 40 to 60 ° C. If it is less than 40 ° C., the heat resistance of the toner deteriorates, and if it exceeds 70 ° C., the low-temperature fixability becomes insufficient. Due to the coexistence of a modified polyester such as a urea-modified polyester resin, the dry toner of the present invention tends to have good heat-resistant storage stability even when the glass transition point is low, as compared with a known polyester-based toner.

(Release agent)
The release agent (wax) used for the toner of the developer of the present invention is preferably a wax having a melting point of 50 to 120 ° C. As a release agent, it works more effectively between the fixing roller and the toner interface in the dispersion with the binder resin, and it is effective against high temperature offset resistance without applying a release agent such as oil to the fixing roller. Indicates. The melting point of the wax in the present invention was the maximum endothermic peak measured by a differential scanning calorimeter (DSC).

  The following materials are mentioned as a wax component which functions as a mold release agent which can be used in the present invention. That is, as specific examples, waxes and waxes include plant waxes such as carnauba wax, cotton wax, wood wax, rice wax, animal waxes such as beeswax and lanolin, mineral waxes such as ozokerite and cercin, And petroleum waxes such as paraffin, microcrystalline, and petrolatum. In addition to these natural waxes, synthetic hydrocarbon waxes such as Fischer-Tropsch wax and polyethylene wax, and synthetic waxes such as esters, ketones and ethers can be used. Furthermore, fatty acid amides such as 12-hydroxystearic acid amide, stearic acid amide, phthalic anhydride imide, chlorinated hydrocarbon, and poly n-stearyl methacrylate, poly n-lauryl methacrylate, which are low molecular weight crystalline polymer resins A crystalline polymer having a long alkyl group in the side chain, such as a polyacrylate homopolymer or copolymer (for example, a copolymer of n-stearyl acrylate-ethyl methacrylate, etc.) can also be used.

(Coloring agent)
As the colorant used in the toner of the developer of the present invention, all known dyes and pigments can be used. For example, carbon black, nigrosine dye, iron black, naphthol yellow S, Hansa yellow (10G, 5G, G), CAD Muum 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, Antimony Zhu, Permanent Red 4R, Para Red, Faise Red, parachlor ortho nitroaniline red, Resol Fast Scarlet G, Brilliant Fast Scarlet, Brilliant Carmine BS, Permanent Red (F2R, F4R, FRL, FRLL, F4RH), Fast Scarlet VD, Belkan Fast Rubin B, Brilliant Scarlet G, Risor Rubin GX, Permanent Red F5R, Brilliant Carmine 6B, Pigment Scarlet 3B, Bordeaux 5B, Toluidine Maroon, Permanent Bordeaux F2K, Helio Bordeaux BL, Bordeaux 10B, Bon Maroon Light, Bon Maroon Medium, Eosin Lake, Rhodamine Lake B, Rhodamine Lake Y, Alizarin Lake, Thioindigo Red B, Thioindigo Maroon, Oil Red, Kinak Don Red, Pyrazolone 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 , Indanthrene Blue (RS, BC), Indigo, Ultramarine, Bitumen, 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 green lake, phthalocyanine green, anthraquinone green, titanium oxide, zinc white, litbon and mixtures thereof can be used. The content of the colorant is usually 1 to 15% by mass, preferably 3 to 10% by mass with respect to the toner.

(Master Badge)
The colorant used in the present invention can also be used as a master batch combined with a resin. As the binder resin to be kneaded together with the production of the masterbatch or the masterbatch, in addition to the above-mentioned modified and unmodified polyester resins, styrene such as polystyrene, poly p-chlorostyrene, and polyvinyltoluene, and polymers of substitution products thereof. Styrene-p-chlorostyrene copolymer, styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-vinylnaphthalene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer Polymer, styrene-butyl acrylate copolymer, styrene-octyl acrylate copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-α -Methyl chloromethacrylate copolymer, styrene -Acrylonitrile copolymer, styrene-vinyl methyl ketone copolymer, styrene-butadiene copolymer, styrene-isoprene copolymer, styrene-acrylonitrile-indene copolymer, styrene-maleic acid copolymer, styrene-maleic acid Styrenic copolymers such as ester copolymers; polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polypropylene, polyester, epoxy resin, epoxy polyol resin, polyurethane, polyamide, polyvinyl butyral, polyacryl Acid resins, rosins, modified rosins, terpene resins, aliphatic or alicyclic hydrocarbon resins, aromatic petroleum resins, chlorinated paraffins, paraffin waxes and the like can be used, and these can be used alone or in combination.

  The master batch can be obtained by mixing and kneading a resin for a master batch and a colorant under a high shear force to obtain a master batch. 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. Can be used as it is, so that it is not necessary to dry and is preferably used. For mixing and kneading, a high shear dispersion device such as a three-roll mill is preferably used.

  A method for producing an electrophotographic toner in which particles comprising a colorant and a resin and particles comprising at least charge control agent particles are mixed together in a container using a rotating body in order to adhere and immobilize the charge control agent on the toner particle surface. However, in this method, the object of the present invention is to include a step of mixing at a peripheral speed of the rotating body of 40 to 150 m / sec in a container without a fixing member protruding from the inner wall of the container. Toner particles are obtained.

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

  In the present invention, the amount of charge control agent used is determined uniquely by the type of binder resin, the presence or absence of additives used as necessary, and the toner production method including the dispersion method, and is uniquely limited. Although it is not a thing, Preferably it is used in 0.1-10 mass parts with respect to 100 mass parts of binder resin. Preferably, the range of 0.2-5 mass parts is good. When the amount exceeds 10 parts by mass, the chargeability of the toner is too high, the effect of the main charge control agent is reduced, the electrostatic attraction 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 and release agents can be melt-kneaded together with the masterbatch and the resin, and of course, they may be added when dissolved and dispersed in an organic solvent.

(External additive)
As the toner used in the present invention, an external additive can be used to assist the fluidity, developability and chargeability of the colored particles, and inorganic fine particles can be preferably used as such an external additive.

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 use ratio of the inorganic fine particles is preferably 0.01 to 5% by mass of the toner, and particularly preferably 0.01 to 2.0% by mass.

  Specific examples of the inorganic fine particles used for the external additive include, for example, silica, alumina, titanium oxide, barium titanate, magnesium titanate, calcium titanate, strontium titanate, zinc oxide, tin oxide, silica sand, clay, Examples thereof include mica, wollastonite, 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, as the fluidity imparting agent, it is preferable to use hydrophobic silica fine particles and hydrophobic titanium oxide fine particles in combination. In particular, when stirring and mixing are performed using particles having an average particle diameter of 50 nm or less, the electrostatic force and van der Waals force with the toner are remarkably improved, so that a desired charge level is obtained. It is clear that even with stirring and mixing inside the developing machine, a fluidity-imparting agent is not detached from the toner, a good image quality that does not generate fireflies and the like can be obtained, and the residual toner can be further reduced became.

  Titanium oxide fine particles are excellent in environmental stability and image density stability, but have a tendency to deteriorate the charge rising characteristics. Therefore, if the amount of titanium oxide fine particles added is larger than the amount of silica fine particles added, the side effects are affected. It can be considered large. However, when the addition amount of the hydrophobic silica fine particles and the hydrophobic titanium oxide fine particles is in the range of 0.3 to 1.5 wt%, the charge rising characteristics are not greatly impaired, and the desired charge rising characteristics can be obtained, that is, repeated copying. It has been found that stable image quality can be obtained and toner blowing can be suppressed even if the process is performed.

(Binder resin production method)
The binder resin can be produced by the following method.

  Polyol (PO) and polycarboxylic acid (PC) are heated to 150-280 ° C. in the presence of a known esterification catalyst such as tetrabutoxytitanate, dibutyltin oxide, etc., and the generated water is distilled off as necessary. Thus, a polyester having a hydroxyl group is obtained. Next, this is reacted with polyisocyanate (PIC) at 40 to 140 ° C. to obtain a polyester prepolymer (A) having an isocyanate group. Further, this A is reacted with amines (B) at 0 to 140 ° C. to obtain a polyester (UMPE) modified with a urea bond. The number average molecular weight of this modified polyester is 1000 to 10000, preferably 1500 to 6000. When reacting PIC and when reacting A and B, a solvent can be used if necessary.

  Usable solvents include aromatic solvents (toluene, xylene, etc.); ketones (acetone, methyl ethyl ketone, methyl isobutyl ketone, etc.); esters (ethyl acetate, etc.); amides (dimethylformamide, dimethylacetamide, etc.) and ethers And those inert to isocyanates (PIC), such as tetrahydrofuran (such as tetrahydrofuran). When polyester (PE) that is not modified with a urea bond is used in combination, PE is produced in the same manner as the polyester having a hydroxyl group, and this is dissolved in the solution after completion of the UMPE reaction and mixed.

(Toner production method in aqueous medium)
The toner of the present invention can be produced by the following method, but is not limited thereto. As the aqueous medium used in the present invention, water alone may be used, but a solvent miscible with water may be used in combination. Examples of the miscible solvent include alcohol (methanol, isopropanol, ethylene glycol, etc.), dimethylformamide, tetrahydrofuran, cellosolves (methylcellosolve, etc.), lower ketones (acetone, methyl ethyl ketone, etc.) and the like.

  In the present invention, a urea-modified polyester (UMPE) or the like can be obtained by reacting a reactive modified polyester such as a polyester prepolymer (A) having an isocyanate group with an amine (B) in an aqueous medium. As a method for stably forming a dispersion comprising a modified polyester such as urea-modified polyester or a reactive modified polyester such as prepolymer (A) in an aqueous medium, a modified polyester such as urea-modified polyester or a pre-polymer can be used in an aqueous medium. Examples thereof include a method in which a composition of a toner raw material composed of reactive modified polyester such as polymer (A) is added and dispersed by shearing force. Reactive modified polyester such as prepolymer (A) and other toner composition (hereinafter referred to as toner raw material), colorant, colorant masterbatch, release agent, charge control agent, unmodified polyester resin, etc. Mixing may be performed when the dispersion is formed in the medium, but it is more preferable to mix the toner raw materials in advance and then add and disperse the mixture in the aqueous medium. In the present invention, other toner materials such as a colorant, a release agent, and a charge control agent do not necessarily have to be mixed when forming particles in an aqueous medium, but after the particles are formed. , May be added. For example, after forming particles not containing a colorant, the colorant can be added by a known dyeing method.

  The dispersion method is not particularly limited, and known equipment such as a low-speed shear method, a high-speed shear method, a friction method, a high-pressure jet method, and an ultrasonic wave can be applied. In order to make the particle size of the dispersion 2 to 20 μm, a high-speed shearing type is preferable. When a high-speed shearing disperser is used, the rotational speed is not particularly limited, but is usually 1000 to 30000 rpm, preferably 5000 to 20000 rpm. The dispersion time is not particularly limited, but in the case of a batch method, it is usually 0.1 to 5 minutes. The temperature during dispersion is usually 0 to 150 ° C. (under pressure), preferably 40 to 98 ° C. Higher temperatures are preferred in that the dispersion of the urea-modified polyester or prepolymer (A) has a low viscosity and is easy to disperse.

  The amount of the aqueous medium used is usually 50 to 2000 parts by mass, preferably 100 to 1000 parts by mass with respect to 100 parts of the toner composition containing polyester such as urea-modified polyester and prepolymer (A). If the amount is less than 50 parts by mass, the dispersion state of the toner composition is poor, and toner particles having a predetermined particle size cannot be obtained. If it exceeds 20000 parts by mass, it is not economical. 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.

  Various dispersants for emulsifying and dispersing the oily phase in which the toner composition is dispersed are used in the liquid containing water. Such a dispersant includes a surfactant, an inorganic fine particle dispersant, a polymer fine particle dispersant and the like.

  As surfactants, anionic surfactants such as alkylbenzene sulfonates, α-olefin sulfonates, phosphate esters, alkylamine salts, amino alcohol fatty acid derivatives, polyamine fatty acid derivatives, amine salt types such as imidazoline, Quaternary ammonium salt type cationic surfactants such as alkyltrimethylammonium salt, dialkyldimethylammonium salt, alkyldimethylbenzylammonium salt, pyridinium salt, alkylisoquinolinium salt, benzethonium chloride, fatty acid amide derivative, polyhydric alcohol Nonionic surfactants such as derivatives, for example, amphoteric surfactants such as alanine, dodecyldi (aminoethyl) glycine, di (octylaminoethyl) glycine and N-alkyl-N, N-dimethylammonium betaine It is below.

  Further, by using a surfactant having a fluoroalkyl group, the effect can be increased in a very small amount. Preferred anionic surfactants having a fluoroalkyl group include fluoroalkyl carboxylic acids having 2 to 10 carbon atoms and metal salts thereof, disodium perfluorooctanesulfonyl glutamate, 3- [omega-fluoroalkyl (C6-C11 ) Oxy] -1-alkyl (C3-C4) sodium sulfonate, 3- [omega-fluoroalkanoyl (C6-C8) -N-ethylamino] -1-propanesulfonic acid sodium, fluoroalkyl (C11-C20) carvone Acids and metal salts, perfluoroalkylcarboxylic acids (C7 to C13) and metal salts thereof, perfluoroalkyl (C4 to C12) sulfonic acids and metal salts thereof, perfluorooctanesulfonic acid diethanolamide, N-propyl-N- ( 2-hydroxyethyl) -Fluorooctanesulfonamide, perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salt, perfluoroalkyl (C6-C10) -N-ethylsulfonylglycine salt, monoperfluoroalkyl (C6-C16) ethyl phosphate, etc. Is mentioned.

  Trade names of the above anionic surfactants include Surflon S-111, S-112, S-113 (Asahi Glass Co., Ltd.), Florard FC-93, FC-95, FC-98, FC-129 (Sumitomo 3M) Manufactured), Unidyne DS-101, DS-102 (manufactured by Daikin Industries, Ltd.), Mega-Fac F-110, F-120, F-113, F-191, F-812, F-833 (manufactured by Dainippon Ink, Inc.) ), Xtop EF-102, 103, 104, 105, 112, 123A, 123B, 306A, 501, 201, 204 (manufactured by Tochem Products Co., Ltd.), Footgent F-100, F150 (manufactured by Neos Co., Ltd.), etc. Can be mentioned.

  Examples of the cationic surfactant include aliphatic primary, secondary or secondary amine acids having a fluoroalkyl group, aliphatic quaternary ammonium salts such as perfluoroalkyl (C6-C10) sulfonamidopropyltrimethylammonium salt, Benzalkonium salt, benzethonium chloride, pyridinium salt, imidazolinium salt and the like can be mentioned.

  Trade names of the above-mentioned cationic surfactants include Surflon S-121 (manufactured by Asahi Glass Co., Ltd.), Florard FC-135 (manufactured by Sumitomo 3M Co., Ltd.), Unidyne DS-202 (manufactured by Daikin Industries Co., Ltd.), MegaFuck F-150 Examples thereof include F-824 (manufactured by Dainippon Ink Co., Ltd.), Xtop EF-132 (manufactured by Tochem Products), and Footgent F-300 (manufactured by Neos).

  In addition, tricalcium phosphate, calcium carbonate, titanium oxide, colloidal silica, hydroxyapatite and the like can be used as an inorganic compound dispersant that is hardly soluble in water.

  Further, the same effect as that of the inorganic dispersant was confirmed for the fine particle polymer. For example, MMA polymer fine particles 1 μm and 3 μm, styrene fine particles 0.5 μm and 2 μm, styrene-acrylonitrile fine particle polymer 1 μm, (PB-200H (manufactured by Kao) SGP (Soken), Technopolymer SB (Sekisui Plastics Industry), SGP -3G (Soken) Micropearl (Sekisui Fine Chemical)).

  In addition, as a dispersant that can be used in combination with the above-described inorganic dispersant and fine particle polymer, dispersed droplets may be stabilized by 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, or (meth) acrylic simple substances containing hydroxyl groups 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-methylol acrylamide, N-methylol methacrylamide, etc., vinyl alcohol or ethers with vinyl alcohol, such as vinyl methyl ether, vinyl ethyl ether, vinyl propyl ether, or esters of compounds containing vinyl alcohol and a carboxyl group For example, pinyl acetate, pinyl propionate, vinyl butyrate, acrylamide, methacrylamide, diacetone acrylamide or acid chlorides such as these methylol compounds, acrylic acid chloride, methacrylic acid chloride, pinylviridine, vinylpyrrolidone, vinylimidazole, ethyleneimine Homopolymers or copolymers such as those having a nitrogen atom or its heterocyclic ring, polyoxyethylene, polyoxypropylene Polyoxyethylene alkylamine, polyoxypropylene alkylamine, polyoxyethylene alkylamide, polyoxypropylene alkylamide, polyoxyethylene nonyl phenyl ether, polyoxyethylene lauryl phenyl ether, polyoxyethylene stearyl phenyl ester, polyoxyethylene nonyl Polyoxyethylenes such as phenyl esters, celluloses such as methyl cellulose, hydroxyethyl cellulose, and hydroxypropyl cellulose can be used.

  In order to produce coalesced particles by stirring and converging the obtained emulsified dispersion (reactant) in a certain temperature range lower than the resin glass transition temperature and the organic solvent concentration range, The shaped toner particles can be produced by gradually raising the temperature in a laminar stirring state and removing the solvent. In addition, when an acid such as calcium phosphate salt or an alkali-soluble substance is used as the dispersion stabilizer, the calcium phosphate salt is removed from the fine particles by a method such as dissolving the calcium phosphate salt with an acid such as hydrochloric acid and washing with water. To do. It can also be removed by operations such as enzymatic degradation. When a dispersant is used, the dispersant can remain on the toner particle surface.

  Furthermore, in order to reduce the viscosity of the dispersion medium containing the toner composition, a solvent in which a polyester such as urea-modified polyester or prepolymer (A) is soluble can be used. The use of a solvent is preferable in that the particle size distribution becomes sharp. The solvent is preferably volatile with a boiling point of less than 100 ° C. from the viewpoint of easy removal of the solvent.

  Examples of such solvents include toluene, xylene, benzene, carbon tetrachloride, methylene chloride, 1,2-dichloroethane, 1,1,2-trichloroethane, trichloroethylene, chloroform, monochlorobenzene, dichloroethylidene, methyl acetate, acetic acid. Ethyl, methyl ethyl ketone, methyl isobutyl ketone and the like can be used alone or in combination of two or more. In particular, aromatic solvents such as toluene and xylene and halogenated hydrocarbons such as methylene chloride, 1,2-dichloroethane, chloroform, and carbon tetrachloride are preferable. The usage-amount of a solvent is 0-300 parts normally with respect to 100 parts of prepolymers (A), Preferably it is 0-100 parts, More preferably, it is 25-70 parts. When a solvent is used, the solvent (solvent) is removed from the resultant reaction product under normal pressure or reduced pressure after the extension and / or crosslinking reaction of the modified polyester (prepolymer) with an amine.

  The elongation and / or crosslinking reaction time is selected, for example, depending on the reactivity of the isocyanate group structure of the prepolymer (A) and the amines (B), but is usually 10 minutes to 40 hours, preferably 2 to 24 hours. It's time. The reaction temperature is generally 0 to 150 ° C, preferably 40 to 98 ° C. Moreover, a well-known catalyst can be used as needed. Specific examples include dibutyltin laurate and dioctyltin laurate. In addition, as an extender and / or a crosslinking agent, the above-described amines (B) are used.

  In the present invention, prior to desolvation from the dispersion (reaction liquid) after the elongation and / or cross-linking reaction, the dispersion is stirred and converged in a certain temperature range lower than the resin glass transition temperature and in the organic solvent concentration range. It is preferable to remove the solvent at 10 to 50 ° C. after preparing the coalesced particles and confirming the shape. The toner is deformed by liquid agitation before the removal of the solvent. In the present invention, since the layered inorganic mineral in which at least a part of the ions between the layers is modified with organic ions is contained, the deformation is surely caused. Since the granulation conditions are not absolute, it is necessary to appropriately select the conditions. In addition, when the concentration of the organic solvent contained in the granulation is high, the viscosity of the emulsified liquid will be lowered, and when the droplets coalesce, the particle shape tends to be spheroidized, so there is a good balance. It is necessary to adjust the viscosity.

  Further, when the concentration of the organic solvent contained in the granulation is low, when the droplets coalesce, the viscosity of the droplets is high and the particles do not become complete particles but come off. For this reason, it is necessary to set an optimum condition, and the toner shape can be appropriately adjusted by selecting a condition. Furthermore, in the present invention, the shape can also be adjusted by the content of a layered inorganic mineral (organic modified layered inorganic mineral) in which at least some of the ions between layers are modified with organic ions. The organically modified layered inorganic mineral is preferably contained in an amount of 0.05 to 10% in the solid content in the solution or dispersion. If it is less than 0.05%, the target oil phase viscosity cannot be obtained, and the target shape cannot be obtained. Since the droplet viscosity is low, even if the droplets coalesce during the stirring and converging, the target coalesced particles cannot be obtained, resulting in a spherical shape. If it exceeds 10%, the manufacturability deteriorates, the viscosity of the droplet becomes too high to form coalesced particles, and further the fixing performance deteriorates.

  On the other hand, the ratio Dv / Dn between the volume average particle diameter Dv and the number average particle diameter (Dn) of the toner described above mainly adjusts, for example, the water layer viscosity, the oil layer viscosity, the characteristics of the resin fine particles, and the addition amount. Can be controlled. In addition, Dv and Dn can be controlled by adjusting, for example, characteristics of resin fine particles, addition amount, and the like.

[Process cartridge]
Next, the process cartridge of the present invention will be described. FIGS. 3 and 4 show an example of a configuration diagram of a process cartridge holding the electrophotographic developer of the present invention. A process cartridge 10 shown in FIG. 3 is configured to integrally support a photosensitive member 11, a charging unit 12, a developing unit 13, and a cleaning unit 14 and to be detachable from the main body of the image forming apparatus.

  FIG. 4 shows an example of a process cartridge in which the state of holding the electrophotographic developer of the present invention is clearly shown. In FIG. 4, reference numerals indicate 1: photoconductor (photoconductor drum), 2: developing device, 3-3: stagnant developer, 3a: toner, 3b: magnetic carrier, 4: developing sleeve, and 5: magnet roller. , 6: Doctor blade, 7: Developer storage case, 7a: Pre-doctor, 8: Toner hopper, 8a: Toner supply port, 9: Toner transport and stirring paddle, 50: Charging roller, 58: Cleaning device, 80: Magnetic field Forming means, D: development area, S: developer accommodating portion.

  In this process cartridge, the photosensitive member is rotationally driven at a predetermined peripheral speed, and the photosensitive member receives a uniform positive or negative electric potential with a positive or negative predetermined potential on its peripheral surface by the charging means during the rotation process. Image exposure is performed from image exposure means such as scanning exposure, and thus electrostatic latent images are sequentially formed on the peripheral surface of the photoreceptor. The formed electrostatic latent images are then developed with toner by the developing means, and the developed toner image is developed. Are sequentially transferred by the transfer unit to the transfer material fed in synchronization with the rotation of the photoconductor between the photoconductor and the transfer unit from the paper feeding unit. The transfer material that has received the image transfer is separated from the surface of the photosensitive member, introduced into an image fixing means outside the process cartridge, fixed on the image, and printed out as a printed matter (copy). The surface of the photoreceptor after the image transfer is cleaned by removing the transfer residual toner by a cleaning unit as necessary, and after being further neutralized, it is repeatedly used for image formation. That is, an image forming method using a process cartridge of this form includes a step of forming an electrostatic latent image on an image carrier, and developing the visible image with a developer composed of at least a carrier and a toner. The electrophotographic developer of the present invention is used as a developer, including a step of forming a visible image and a step of transferring the obtained visible image to a recording member.

  According to the process cartridge of the present invention, since the electrophotographic developer is held, a high-quality image with excellent fine dot reproducibility can be obtained by the toner supplied from the carrier of the electrophotographic developer. Also, it has excellent low-temperature fixability and high reliability in cleaning.

[Image forming apparatus and image forming method]
Next, the image forming apparatus will be described. The image forming apparatus of the present invention includes at least a photoconductor, a developing unit that forms an image on the photoconductor, a transfer unit that transfers an image on the photoconductor to a transfer material, and an image on the transfer material. In the present invention, the image forming apparatus includes a fixing unit for fixing, and includes the above-described components such as the photosensitive member, the charging unit, the developing unit, the cleaning unit, and the discharging unit. Preferably, the photosensitive member, the developing means using the developer of the present invention, and one or more other means are integrally combined as the above-described process cartridge, and this process cartridge is formed in an image of a copying machine or a printer. It is configured to be detachable from the forming apparatus main body.

  In the image forming apparatus having the developing means using the developer of the present invention, the photosensitive member is rotationally driven at a predetermined peripheral speed. In the rotation process, the photosensitive member receives a uniform positive or negative electric potential on its peripheral surface by the charging means, and then receives image exposure light from an image exposure means such as slit exposure or laser beam scanning exposure. An electrostatic latent image is sequentially formed on the peripheral surface of the body, and the formed electrostatic latent image is then developed with toner by a developing unit, and the developed toner image is transferred between the photosensitive member and the transfer unit from the paper feeding unit. Then, the image is sequentially transferred to the transfer material fed in synchronization with the rotation of the photosensitive member by the transfer means. 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 printed material (copy). The surface of the photoreceptor after the image transfer is cleaned by removing the transfer residual toner by the cleaning means, and after being further neutralized, it is repeatedly used for image formation.

  An image forming method using the image forming apparatus of the present invention includes a step of forming an electrostatic latent image on an image carrier, and developing the electrostatic latent image with a developer composed of at least a carrier and a toner to form a visible image. The electrophotographic developer of the present invention is used as a developer, including a step of forming and a step of transferring and fixing the obtained visible image to a recording member.

  According to the image forming apparatus of the present invention, since the electrophotographic developer of the present invention is used, the edge effect is suppressed over a long period of time, and a fine and high-quality image without color stains can be formed. In addition, high reliability is obtained in cleaning, and excellent low-temperature fixability and fine dot reproducibility make it possible to obtain high-quality images over a long period of time.

  Further, according to the image forming method of the present invention, it is possible to narrow the charge amount distribution of the toner particles and suppress variations in the charge amount of the individual toner particles. As a result, it is possible to form a fine and high-quality image that does not cause an edge effect over a long period of time and has no color stains. In addition, high reliability is obtained in cleaning, and excellent low-temperature fixability and fine dot reproducibility make it possible to obtain high-quality images over a long period of time.

(Example)
EXAMPLES Hereinafter, although an Example and a comparative example are given and this invention is demonstrated further more concretely, this invention is not limited to these. Unless otherwise specified, “part” and “%” are based on mass.

Example 1
[Manufacture of carrier 1]
The following raw materials and the like were weighed in a stirring vessel and stirred with a homomixer for 10 minutes to obtain a silicone resin coating film forming solution.
Silicone resin solution [solid content 23% (SR2410: manufactured by Toray Dow Corning Silicone)] 432.2 parts Aminosilane [solid content 100% (SH6020: manufactured by Toray Dow Corning Silicone)]
0.66 part, inorganic oxide fine particle A [aluminum oxide particle size: 0.40 μm, true specific gravity: 3.9]
145 parts-ionic liquid [IL-A2 (manufactured by Guangei Chemical Industry Co., Ltd.) Ionic conductivity: 6.1 x 10 ⁵ s / cm] 20 parts-300 parts of toluene Firing ferrite powder having an average particle size of 35 µm as a core material ( True specific gravity 5.5) Using 5000 parts, apply the above coating film forming solution on the surface of the core material with a Spira coater (manufactured by Okada Seiko Co., Ltd.) at a coater internal temperature of 40 ° C. And dried. The obtained carrier was fired in an electric furnace at 200 ° C. for 1 hour. After cooling, the ferrite powder bulk was crushed using a sieve having an aperture of 63 μm, and the average particle diameter / coating film thickness (D / h): 1.1, volume specific resistance (logarithmic display): 13.9 [Log ( Ω · cm)] [carrier 1] with magnetization at 1 kOe: 68 Am ² / kg. The inorganic oxide fine particles contained in the resin coating layer at this time had a coverage (C) of 93% with respect to the core material.

  In addition, about the average particle diameter measurement of a core material, what was performed by using the SRA type of a micro track particle size analyzer (Nikkiso Co., Ltd.) and the range setting of 0.7 micrometer or more and 125 micrometers or less was used. The average particle size is D50.

  Binder resin coating film thickness measurement can observe the coating film covering the carrier surface by observing the cross section of the carrier with a transmission electron microscope. .

  Magnetization measurement was performed by the following method using VSM-P7-15 manufactured by Toei Industry Co., Ltd. About 0.15 g of the sample was weighed, the sample was filled in a cell having an inner diameter of 2.4 mmφ and a height of 8.5 mm, and measured under a magnetic field of 1000 oersted (Oe).

[Toner]: (Toner 1)
229 parts of bisphenol A ethylene oxide 2-mole adduct, 529 parts of bisphenol A propion oxide 3-mole adduct, 208 parts of terephthalic acid, 46 parts of adipic acid and dibutyltin oxide 2 parts were added and reacted at 230 ° C. under normal pressure for 8 hours. Furthermore, after reacting under reduced pressure of 10 to 15 mmHg for 5 hours, 44 parts of trimellitic anhydride was added to the reaction vessel and reacted at 180 ° C. for 2 hours under normal pressure to synthesize an unmodified polyester resin. The obtained unmodified polyester resin had a number average molecular weight of 2500, a mass average molecular weight of 6700, a glass transition temperature of 43 ° C., and an acid value of 25 mgKOH / g.

  1200 parts of water, 540 parts of carbon black Printex 35 (manufactured by Dexa; DBP oil absorption = 42 ml / 100 mg, pH = 9.5) and 1200 parts of the unmodified polyester resin were used using a Henschel mixer (manufactured by Mitsui Mining). Mixed. The resulting mixture was kneaded at 150 ° C. for 30 minutes using two rolls, then rolled and cooled, and pulverized with a pulverizer (manufactured by Hosokawa Micron Corporation) to prepare a master batch.

  In a reaction vessel equipped with a stirrer and a thermometer, 378 parts of unmodified polyester resin, 110 parts of carnauba wax, 22 parts of salicylic acid metal complex E-84 (manufactured by Orient Chemical Co., Ltd.) and 947 parts of ethyl acetate were charged and stirred. The temperature was raised to 80 ° C., held at 80 ° C. for 5 hours, and then cooled to 30 ° C. over 1 hour. Next, 500 parts of the master batch and 500 parts of ethyl acetate were charged into the reaction vessel and mixed for 1 hour to obtain a raw material solution.

  1324 parts of the obtained raw material solution was transferred to a reaction vessel, and filled with 80% by volume of 0.5 mm zirconia beads using a bead mill Ultra Visco Mill (manufactured by Imex Co., Ltd.). 3 passes under the condition of 6 m / sec. I. Pigment Red and carnauba wax were dispersed to obtain a wax dispersion.

  Next, 1324 parts of a 65 mass% ethyl acetate solution of unmodified polyester resin was added to the obtained wax dispersion. A layered inorganic mineral montmorillonite (Clayton APA Southern Clay modified at least partly with a quaternary ammonium salt having a benzyl group) was added to 200 parts of a dispersion obtained by one pass using Ultraviscomyl under the same conditions as above. 3 parts) (manufactured by Products) are added. K. Using a homodisper (manufactured by Koki Kogyo Co., Ltd.), the mixture was stirred for 30 minutes to obtain a dispersion of toner material.

  The viscosity of the obtained dispersion of toner material was measured as follows. Using a parallel plate type rheometer AR2000 (made by D.A. Instruments Japan Co., Ltd.) equipped with a parallel plate with a diameter of 20 mm, the gap was set to 30 μm, and the toner material dispersion was at 25 ° C. After applying a shear force at a shear rate of 30000 seconds-1 for 30 seconds, the viscosity (viscosity A) when the shear rate was changed from 0 seconds-1 to 70 seconds-1 in 20 seconds was measured. Further, using a parallel plate rheometer AR2000, the viscosity (viscosity B) when a shearing force was applied to the dispersion liquid of the toner material at 25 ° C. at a shear rate of 30000 seconds-1 for 30 seconds was measured. The results are shown in Table 1 below.

  In a reaction vessel equipped with a cooling tube, a stirrer and a nitrogen introduction tube, 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, 22 parts of trimellitic anhydride And 2 parts of dibutyltin oxide were added and reacted at 230 ° C. for 8 hours under normal pressure. Next, it was made to react under reduced pressure of 10-15mHg for 5 hours, and the intermediate polyester resin was synthesize | combined.

  The obtained intermediate polyester resin had a number average molecular weight of 2100, a mass average molecular weight of 9,500, a glass transition temperature of 55 ° C., an acid value of 0.5 mgKOH / g, and a hydroxyl value of 51 mgKOH / g.

  Next, 410 parts of the intermediate polyester resin, 89 parts of isophorone diisocyanate, and 500 parts of ethyl acetate are charged into a reaction vessel equipped with a cooling pipe, a stirrer, and a nitrogen introduction pipe, and reacted at 100 ° C. for 5 hours. Was synthesized. The free isocyanate content of the obtained prepolymer was 1.53% by mass.

  In a reaction vessel equipped with a stir bar and a thermometer, 170 parts of isophoronediamine and 75 parts of methyl ethyl ketone were charged and reacted at 50 ° C. for 5 hours to synthesize a ketimine compound. The amine value of the obtained ketimine compound was 418 mgKOH / g.

  In a reaction vessel, 749 parts of a dispersion of toner material, 115 parts of a prepolymer and 2.9 parts of a ketimine compound are charged and mixed at 5,000 rpm for 1 minute using a TK homomixer (manufactured by Tokushu Kika). A mixture was obtained.

  In a reaction vessel equipped with a stirring bar and a thermometer, 683 parts of water, 11 parts of reactive emulsifier (sodium salt of sulfuric acid ester of methacrylic acid ethylene oxide adduct), Eleminol RS-30 (manufactured by Sanyo Chemical Industries), styrene 83 Parts, 83 parts of methacrylic acid, 110 parts of butyl acrylate and 1 part of ammonium persulfate were stirred at 400 rpm for 15 minutes to obtain an emulsion. The emulsion was heated, heated to 75 ° C. and reacted for 5 hours. Next, 30 parts of a 1% by mass ammonium persulfate aqueous solution was added and aged at 75 ° C. for 5 hours to prepare a resin particle dispersion.

(Dispersion particle size and dispersion particle size distribution of toner material liquid)
The measurement of the dispersoid particle size and dispersion particle size distribution of the toner material liquid was performed using “Microtrac UPA-150” (manufactured by Nikkiso Co., Ltd.), and the analysis software “Microtrac Particle Size Analyzer-Ver. -016EE "(manufactured by Nikkiso Co., Ltd.) was used for analysis. Specifically, the toner material liquid and then the solvent used for the toner material liquid preparation were added to a glass 30 ml sample bottle to prepare a 10 mass% dispersion. The obtained dispersion was subjected to a dispersion treatment for 2 minutes with an “ultrasonic wave disperser W-113MK-II” (manufactured by Honda Electronics Co., Ltd.).

  After measuring the background with the solvent used for the toner material liquid to be measured, the dispersion was dropped, and the dispersed particle size was measured under the condition that the sample loading value of the measuring device was in the range of 1-10. In this measurement method, it is important to measure under the condition that the sample loading value of the measuring device is in the range of 1 to 10 from the viewpoint of measurement reproducibility of the dispersed particle size. In order to obtain the sample loading value, it is necessary to adjust the dripping amount of the dispersion.

Measurement and analysis conditions were set as follows. Distribution display: volume, particle size classification selection: standard, number of channels: 44, measurement time: 60 sec, number of measurements: once, particle permeability: transmission, particle refractive index: 1.5, particle shape: non-spherical, density: As the value of 1 g / cm ³ solvent refractive index, the value of the solvent used in the toner material liquid among the values described in “Guidelines on Input Conditions at Measurement” published by Nikkiso Co., Ltd. was used.

  990 parts of water, 83 parts of resin particle dispersion, 37 parts of 48.5% by weight aqueous solution of dodecyl diphenyl ether disulfonate, Eleminol MON-7 (manufactured by Sanyo Chemical Industries), 1% by weight aqueous solution of sodium carboxymethylcellulose polymer dispersant 135 parts of BS-H-3 (Daiichi Kogyo Seiyaku Co., Ltd.) and 90 parts of ethyl acetate were mixed and stirred to obtain an aqueous medium.

  To 1200 parts of the aqueous medium, 867 parts of the oil phase mixed liquid was added and mixed for 20 minutes at 13000 rpm using a TK homomixer to prepare a dispersion (emulsified slurry). Next, the emulsified slurry was charged into a reaction vessel in which a stirrer and a thermometer were set, and after removing the solvent at 30 ° C. for 8 hours, aging was performed at 45 ° C. for 4 hours to obtain a dispersed slurry.

  The volume average particle diameter (Dv) and the number average particle diameter (Dn) of the toner are measured with a particle size measuring device (“Multisizer III”, manufactured by Beckman Coulter, Inc.) at an aperture diameter of 100 μm, and analyzed with software (Beckman Coulter Multisizer 3). The analysis was performed at Version 3.51). Specifically, 0.5 ml of 10 wt% surfactant (alkylbenzene sulfonate Neogen SC-A; manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) was added to a glass 100 ml beaker, 0.5 g of each toner was added, and the mixture was stirred with a micropartel. Subsequently, 80 ml of ion-exchanged water was added. The obtained dispersion was subjected to a dispersion treatment for 10 minutes with an ultrasonic disperser (W-113MK-II, manufactured by Honda Electronics Co., Ltd.). The dispersion was measured using the Multisizer III and Isoton III (manufactured by Beckman Coulter) as the measurement solution. In the measurement, the toner sample dispersion was dropped so that the concentration indicated by the apparatus was 8 ± 2%. In this measurement method, it is important that the concentration is 8 ± 2% from the viewpoint of the reproducibility of the particle size. Within this concentration range, no error occurs in the particle size.

  After 100 parts by mass of the dispersion slurry was filtered under reduced pressure, 100 parts of ion-exchanged water was added to the filter cake, mixed at 12000 rpm for 10 minutes using a TK homomixer, and then filtered. To the obtained filter cake, 10% by mass hydrochloric acid was added to adjust the pH to 2.8, and the mixture was mixed for 10 minutes at 12,000 rpm using a TK homomixer, followed by filtration. Furthermore, 300 parts of ion-exchanged water was added to the obtained filter cake, mixed for 10 minutes at 12000 rpm using a TK homomixer, and then filtered twice to obtain a final filter cake. The obtained final filter cake was dried at 45 ° C. for 48 hours using a circulating dryer, and sieved with a mesh having a mesh size of 75 μm to obtain toner mother particles.

  To 100 parts of the obtained toner base particles, 1.0 part of hydrophobic silica as an external additive and 0.5 part of hydrophobized titanium oxide are added and mixed using a Henschel mixer (Mitsui Mining Co., Ltd.). The toner was manufactured. This is referred to as [Toner 1].

  7 parts of [Toner 1] and 93 parts of [Carrier 1] thus obtained were mixed and stirred to obtain a developer having a toner concentration of 7% by mass, color stain, carrier adhesion, image density, durability (charge reduction amount, resistance) Change). Table 1 shows the main characteristics of the developer (toner circularity, carrier volume resistivity, coverage, D / h, magnetic moment), and Table 2 shows the evaluation results.

(Evaluation method)
The evaluation methods and conditions in the examples are shown below.
<Cleanability>
The cleaning property was evaluated as follows. The toner remaining on the photoconductor after passing the cleaning process at the initial stage and after printing 1000 sheets and 100,000 sheets is transferred to a white paper using a scotch tape (manufactured by Sumitomo 3M) and measured with a Macbeth reflection densitometer RD514 type. When the difference from the blank was 0.01 or less, it was judged as good (◯), and when it exceeded 0.01, it was judged as bad (x).

<Color stain>
The ΔE value of the color monochromatic image was evaluated after running up to 30,000 image charts of 0.5% image area with a commercially available digital full color printer (image Neo Neo C455 manufactured by Ricoh). A single color image at the initial stage and after 30000 sheets is output, and a ΔE value is obtained according to the following equation. When ΔE is 2 or less, there is no color stain (◯), when ΔE is 2 to 4, color stain is not noticeable (Δ), no change in color tone is indicated, and when ΔE is 4 or more, color stain is clearly noticeable (×) be pointed out.

  After image output, the image density is measured by X-RITE 938 (manufactured by x-rite). CIEEL *, CIEa *, and CIEb * at a point where the yellow image density is 1.4 ± 0.5 are measured at three points to obtain an average value and substituted into the following equation to calculate a ΔE value.

ΔE = √ ((initial L *) ² + (initial a *) ² + (initial b *) ² ) −√ ((post-run L *) ² + (post-run a *) ² + (post-run b *) ² )
<Carrier adhesion>
The developer is set on a commercially available digital full-color printer (image Neo Neo C455 manufactured by Ricoh), and the surface of the photosensitive member is developed with a charging potential of DC 740 V and a developing bias of 600 V (the ground potential is fixed at 140 V), and the dot-forming halftone is developed. The number of carriers attached to the surface was counted by observing with a magnifying glass, and the average number of carriers attached per 100 cm 2 was taken as the edge carrier attached amount. The evaluation was as follows: ◎: 20 or less, ○: 21 or more and 60 or less, Δ: 61 or more and 80 or less, ×: 81 or more, ◎ ○ △ was passed and × was rejected.

  Also, the blank spot evaluation (image part) is set to a charging potential of DC 740 V and a developing bias of 600 V (the background potential is fixed to 140 V), a full-color image (A3 size) is output, and the number of blank spots on the image is counted. . The evaluation was as follows: ◎: 5 or less, ◯: 6 or more and 10 or less, △: 11 or more and 20 or less, ×: 21 or more, ◎ ○ △ was accepted and x was rejected.

<Image density>
After running 300,000 image charts with 50% image area in monochrome mode, the solid image is output to 6000 paper manufactured by Ricoh, and the image density is measured by X-Rite (manufactured by X-Rite). It was. In Table 2 below, 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 ◯, and when it is 1.2 or more and less than 1.4, it is △. In the case of less than 1.2, x is indicated.

<Durability>
The developer was set in a commercially available digital full-color printer (image Neo Neo C455 manufactured by Ricoh Co., Ltd.), and a running evaluation of 300,000 sheets was performed with an image chart of 50% image area in a single color mode. The judgment was made based on the amount of charge reduction of the carrier after the running. The amount of decrease in resistance was evaluated by running 300,000 sheets with an image chart of 0.5% image area in the monochromatic mode. And it judged with the amount of resistance fall of the career which finished this running.

  Here, the amount of change in the charge amount is a room temperature and humidity room (temperature: 23.5 ° C., humidity: 60% RH), which is conditioned for 30 minutes or more in an unsealing system, and the initial carrier of 6.000 g and the toner of 0.452 g. After being added to a stainless steel container, it was sealed, and a sample which was friction-charged with an amplitude of about 1100 times with a YS-LD (a shaker manufactured by Yayoi Co., Ltd.) for 5 minutes on a scale 150 The carrier obtained by removing the toner in the developer after running from the charge amount (Q1) measured by a simple blow-off method [manufactured by Toshiba Chemical Co., Ltd .: TB-200] It means the amount obtained by subtracting the charge amount (Q2) measured by the same method, and the target value is within ± 10.0 (μc / g).

  Here, the amount of resistance change refers to the carrier from which the toner in the developer after running can be removed by the blow-off device from the resistance value (R1) obtained by the resistance measurement method described above for the initial carrier. It means an amount obtained by subtracting the value (R2) measured by the same method as the resistance measuring method, and the target value is 3.0 [Log (Ω · cm)] in absolute value. Further, the cause of the resistance change is scraping of the binder resin film of the carrier, spent toner component, particle detachment in the carrier coating film, etc., and reducing these can suppress the resistance change amount. .

(Example 2)
D / h: 0.9, volume resistivity: 14.1 [Log (Ω), except that the coating layer formulation was changed to a mixed system of acrylic resin and silicone resin as described below. Cm)] and magnetization: 68 Am2 / kg [Carrier 2] was obtained. The inorganic oxide particles contained in the resin coating layer at this time had a coverage of 83% with respect to the core material.
・ Acrylic resin solution (solid content 50%) 34.2 parts ・ Guanamine solution (solid content 70%) 9.7 parts ・ Acid catalyst (solid content 40%) 0.19 parts ・ Silicone resin solution [solid content 20% ( SR2410: manufactured by Toray Dow Corning Silicon Co., Ltd.)] 432.2 parts, aminosilane (100% solids (SH6020: manufactured by Toray Dow Corning Silicon Co.)) 3.42 parts, ionic liquid IL-A2 (Guangei Chemical Co., Ltd.) Kogyo Co., Ltd.) 20 parts [Ion conductivity: 6.1 × 10 ⁵ s / cm]
Inorganic oxide fine particle B (aluminum oxide particle size: 0.37 μm, true specific gravity 3.9)
97 parts [Carrier 2] and [Toner 1] obtained in this way were evaluated as developers by the same method as in Example 1. Table 1 shows the main characteristics of the developer (toner circularity, carrier volume resistivity, coverage, D / h, magnetic moment), and Table 2 shows the evaluation results.

(Example 3)
D / h: 1.9, specific volume resistance: 13.1 [Log (Ω), except that the coating layer formulation described below was changed in the formulation ratio of acrylic resin and silicone resin. Cm)], magnetization: 68 Am2 / kg [Carrier 4] was obtained. The inorganic oxide particles contained in the resin coating layer at this time had a coverage of 83% with respect to the core material.
-Acrylic resin solution (solid content 50%) 17.1 parts-Guanamin solution (solid content 70%) 4.85 parts-Acidic catalyst (solid content 40%) 0.10 parts-Silicone resin solution [solid content 20% ( SR2410: manufactured by Toray Dow Corning Silicone)] 216.2 parts, aminosilane [100% solids (SH6020: manufactured by Toray Dow Corning Silicone)] 1.68 parts, ionic liquid (IL-A2 Guangei Chemical Co., Ltd.) Industrial Co., Ltd. ion conductivity: 6.1 × 10 ⁵ s / cm] 20 parts

Inorganic oxide fine particle B (aluminum oxide particle size: 0.37 μm, true specific gravity 3.9)
97 parts / toluene 1600 parts [Carrier 3] and [Toner 1] thus obtained were developed into a developer in the same manner as in Example 1 and evaluated. Table 1 shows the main characteristics of the developer (toner circularity, carrier volume resistivity, coverage, D / h, magnetic moment), and Table 2 shows the evaluation results.

Example 4
D / h: 0.4, volume resistivity: 16.5 [Log (Ω), except that the coating layer formulation described below was changed in the formulation ratio of acrylic resin and silicone resin.・ Cm)
] [Carrier 5] with a magnetization of 68 Am2 / kg was obtained. The inorganic oxide particles contained in the resin coating layer at this time had a coverage of 83% with respect to the core material.
・ Acrylic resin solution (solid content 50%) 158.8 parts ・ Guanamine solution (solid content 70%) 49.6 parts ・ Acid catalyst (solid content 40 mass%) 0.88 parts ・ Silicone resin solution [solid content 20% (SR2410: manufactured by Toray Dow Corning Silicone)] 743.2 parts, aminosilane (solid content 100% (SH6020: manufactured by Toray Dow Corning Silicone)) 1.68 parts, ionic liquid [IL-A2 ( Koei Chemical Industry Co., Ltd.) Ion conductivity: 6.1 × 10 ⁵ S / cm] 20 parts / Inorganic oxide fine particles B (aluminum oxide particle size: 0.37 μm, true specific gravity 3.9) 97 parts / toluene 1600 parts [Carrier 4] and [Toner 1] obtained above were developed into a developer by the same method as in Example 1 and evaluated. Table 1 shows the main characteristics of the developer (toner circularity, carrier volume resistivity, coverage, D / h, magnetic moment), and Table 2 shows the evaluation results.

(Example 5)
In Example 2, inorganic oxide fine particles B, which is a component of the carrier coating film forming solution, instead of aluminum oxide, 110 parts by mass of titanium oxide (anatase) C [particle size: 0.35 μm, true specific gravity 5.0] [Carrier 5] having D / h: 0.9 and volume resistivity: 16.5 [Log (Ω · cm)] was obtained in the same manner as Example 2 except that it was used. The fine particles contained in the resin coating layer at this time had a coverage of 73% with respect to the core material.

  [Toner 1] and [Carrier 5] obtained above were converted into developers by the same method as in Example 1 and evaluated. Table 1 shows the main characteristics of the developer (toner circularity, carrier volume resistivity, coverage, D / h, magnetic moment), and Table 2 shows the evaluation results.

(Example 6)
D / h: 0.9, volume resistivity: 15. In the same manner as in Example 1 except that the carrier has a mass average particle diameter of 18 μm (true specific gravity 5.7) and the coating layer formulation is as described below. 7 [Log (Ω · cm)] and magnetization: 66 Am 2 / kg [Carrier 6] were obtained. The inorganic oxide particles contained in the resin coating layer at this time had a coverage of 71% with respect to the core material.
-Acrylic resin solution (solid content 50%) 68.4 parts-Guanamin solution (solid content 70%) 19.4 parts-Acidic catalyst (solid content 40%) 0.38 parts-Silicone resin solution [solid content 20% ( SR2410: manufactured by Toray Dow Corning Silicone Co., Ltd.]] 864.4 parts, aminosilane [100% solids (SH6020: manufactured by Toray Dow Corning Silicone Co., Ltd.)] 0.46 parts, ionic liquid [IL-A2 (Guangei) Chemical Industries, Ltd.) Ion conductivity: 6.1 × 10 ⁵ s / cm] 20 parts, inorganic oxide fine particles B [Aluminum oxide particle size: 0.37 μm, true specific gravity 3.9]
195 parts [Carrier 6] and [Toner 1] obtained above were converted into developers by the same method as in Example 1 and evaluated. Table 1 shows the main characteristics of the developer (toner circularity, carrier volume resistivity, coverage, D / h, magnetic moment), and Table 2 shows the evaluation results.

(Example 7)
The mass average particle diameter of the carrier is 71 μm (true specific gravity 5.3), and the coating layer formulation is as described below, in the same manner as in Example 1, D / h: 0.6, volume resistivity: 14.5 [ Log (Ω · cm)] and magnetization: 69 Am 2 / kg [Carrier 7]. The inorganic oxide particles contained in the resin coating layer at this time had a coverage of 78% with respect to the core material.
・ Acrylic resin solution (solid content 50%) 34.2 parts ・ Guanamine solution (solid content 70%) 9.7 parts ・ Acid catalyst (solid content 40% by mass) 0.19 parts ・ Silicone resin solution [solid content 20% (SR2410: manufactured by Toray Dow Corning Silicone)] 292.9 parts / aminosilane (solid content: 100% (SH6020: manufactured by Toray Dow Corning Silicone)) 0.42 parts / ionic liquid [IL-A2 ( Guangei Chemical Industry Co., Ltd.) Ionic conductivity: 6.1 × 10 ⁵ S / cm] 20 parts / Inorganic oxide fine particles B [Aluminum oxide particle size: 0.37 μm, true specific gravity 3.9]
60 parts / toluene 800 parts [Carrier 7] and [Toner 1] obtained above were converted into a developer by the same method as in Example 1 and evaluated. Table 1 shows the main characteristics of the developer (toner circularity, carrier volume resistivity, coverage, D / h, magnetic moment), and Table 2 shows the evaluation results.

(Example 8)
In Example 2, a 35 μm sintered ferrite (true specific gravity 5.4) having a low magnetization was used and the magnetization was changed to 35 Am 2 / kg. Similarly, D / h: 0.9, volume resistivity: 13 [Carrier 8] of 9 [Log (Ω · cm)] was obtained. The inorganic oxide particles contained in the resin coating layer at this time had a coverage of 83% with respect to the core material.

  [Carrier 8] and [Toner 1] obtained above were converted into developers by the same method as in Example 1 and evaluated. Table 1 shows the main characteristics of the developer (toner circularity, carrier volume resistivity, coverage, D / h, magnetic moment), and Table 2 shows the evaluation results.

Example 9
In Example 2, D / h: 0.9, volume resistivity: in the same manner except that 35 μm sintered ferrite (true specific gravity 5.5) having high magnetization was used and the magnetization was changed to 93 Am ² / kg. 14.1 [Log (Ω · cm)] [Carrier 9] was obtained. The inorganic oxide particles contained in the resin coating layer at this time had a coverage of 83% with respect to the core material.

  [Carry 9] and [Toner 1] obtained above were converted into developers by the same method as in Example 1 and evaluated. Table 1 shows the main characteristics of the developer (toner circularity, carrier volume resistivity, coverage, D / h, magnetic moment), and Table 2 shows the evaluation results.

(Example 10)
In Example 1, except that the amount of inorganic fine particles added was reduced from 110 parts to 75 parts, in the same manner as in Example 1, D / h: 1.1, volume resistivity: 13.5 [Log (Ω · cm )], [Carrier 10] having a magnetization of 69 Am ² / kg was obtained. The inorganic oxide particles contained in the resin coating layer at this time had a coverage of 43% with respect to the core material.

[Carrier 10] and [Toner 1] obtained above were converted into developers by the same method as in Example 1 and evaluated. Table 1 shows the main characteristics of the developer (toner circularity, carrier volume resistivity, coverage, D / h, magnetic moment), and Table 2 shows the evaluation results.
(Example 11)
In Example 1, the ionic liquid was changed from IL-A2 [ionic conductivity: 6.1 × 10 ⁵ s / cm] to IL-P14 [ionic conductivity: 1.8 × 10 ³ s / cm] (Guangei Chemical Industry). D / h: 1.1, volume resistivity: 13.8 [Log (Ω · cm)], magnetization: 68 Am ² / kg, except that the volume was increased to 30 parts. [Carrier 11] was obtained. The inorganic oxide particles contained in the resin coating layer at this time had a coverage of 93% with respect to the core material. [Carry 11] and [Toner 1] obtained above were converted into developers by the same method as in Example 1 and evaluated. Table 1 shows the main characteristics of the developer (toner circularity, carrier volume resistivity, coverage, D / h, magnetic moment), and Table 2 shows the evaluation results.
(Example 12)
In Example 1, the ionic liquid was changed from IL-A2 [ionic conductivity: 6.1 × 10 ⁵ s / cm] to IL-IM1 [ionic conductivity: 1.5 × 10 ² s / cm] (Guangei Chemical Industry). D / h: 1.1, volume resistivity: 16.3 [Log (Ω · cm)], magnetization: 68 Am ² / kg, except that the volume was increased to 30 parts. [Carrier 12] was obtained. The inorganic oxide particles contained in the resin coating layer at this time had a coverage of 93% with respect to the core material. [Carrier 12] and [Toner 1] obtained above were converted into developers by the same method as in Example 1 and evaluated. Table 1 shows the main characteristics of the developer (toner circularity, carrier volume resistivity, coverage, D / h, magnetic moment), and Table 2 shows the evaluation results.

(Comparative Example 1)
A carrier coating film forming solution having the following composition was dispersed with a homomixer for 10 minutes to obtain a silicone resin coating film forming solution for a carrier coating layer.
[Composition of carrier coating film forming solution]
Silicone resin solution [solid content 23% (SR2410: manufactured by Toray Dow Corning Silicone)] 432.2 parts Aminosilane [solid content 100% (SH6020: manufactured by Toray Dow Corning Silicone)] 0.66 parts Carbon black MA100R (Mitsubishi Chemical Industry Co., Ltd.) 20 parts Toluene 300 parts As a carrier core material, 5000 parts by mass of 35 μm calcined ferrite powder (true specific gravity 5.5) is used, and the above coating film forming solution Was coated on the surface of the core material at a coater internal temperature of 40 ° C. with a Spira coater (Okada Seiko Co., Ltd.) and dried. The obtained carrier was fired in an electric furnace at 200 ° C. for 1 hour. After cooling, the ferrite powder bulk was crushed using a sieve having an aperture of 63 μm to obtain [Carrier 13] having a volume resistivity of 12.9 [Log (Ω · cm)] and a magnetization of 68 Am ² / kg.

  [Carrier 13] and [Toner 1] obtained above were converted into developers by the same method as in Example 1 and evaluated. Table 1 shows the main characteristics of the developer (toner circularity, carrier volume resistivity, coverage, D / h, magnetic moment), and Table 2 shows the evaluation results.

(Comparative Example 2)
The production of the toner was carried out in the same manner as in Example 1 except that 3 parts of Kraton APA (manufactured by Southern Clay Products) used for toner preparation of Example 1 were changed to 45 parts of MEK-ST-UP (manufactured by Nissan Chemical Industries). And [Toner 2] was obtained.

  [Toner 2] and [Carrier 1] obtained above were converted into developers by the same method as in Example 1 and evaluated. Table 1 shows the main characteristics of the developer (toner circularity, carrier volume resistivity, coverage, D / h, magnetic moment), and Table 2 shows the evaluation results.

(Toner evaluation method and evaluation results)
The obtained toner was measured for volume average particle diameter Dv, number average particle diameter Dn, particle size distribution Dv / Dn, average circularity, shape count SF1, and cleaning properties as follows. Dv and Dn were measured with an aperture diameter of 100 μm using a particle size analyzer Multisizer III (manufactured by Beckman Coulter, Inc.). In addition, Dv / Dn was calculated from the obtained results.

  In the present invention, a flow type particle image analyzer (“FPIA-2100”; manufactured by Sysmex Corporation) is used for measurement of ultrafine toner, and analysis software (FPIA-2100 Data Processing Program for FPIA version 00-10) is used. Analysis was performed. Specifically, 0.1 to 0.5 ml of 10 wt% surfactant (alkylbenzene sulfonate Neogen SC-A; Daiichi Kogyo Seiyaku) is added to a glass 100 ml beaker, and each toner 0.1 to 0 is added. 0.5 g was added and stirred with a microspatel, and then 80 ml of ion-exchanged water was added. The obtained dispersion was subjected to a dispersion treatment for 3 minutes with an ultrasonic disperser (manufactured by Honda Electronics Co., Ltd.). The shape and distribution of the toner were measured using the FPIA-2100 until the density of the dispersion was 5000 to 15000 / μl. In this measurement method, it is important that the concentration of the dispersion liquid is 5000 to 15000 / μl from the viewpoint of measurement reproducibility of the average circularity.

  In order to obtain the dispersion concentration, it is necessary to change the conditions of the dispersion, that is, the amount of surfactant to be added and the amount of toner. The amount of the surfactant varies depending on the hydrophobicity of the toner as in the measurement of the toner particle diameter described above. If it is added in a large amount, noise due to bubbles is generated, and if it is too small, the toner cannot be sufficiently wetted. It will be enough. The amount of toner added varies depending on the particle size, and it is small for small particle sizes and needs to be increased for large particle sizes. When the toner particle size is 3 to 7 μm, the toner amount is 0.1 to 0.3. By adding 5 g, the dispersion concentration can be adjusted to 5000 to 15000 / μl.

  SF1 was measured as follows. After vapor deposition on the toner, 100 or more toners were observed using an ultrahigh resolution FE-SEM S-5200 (manufactured by Hitachi, Ltd.) under the condition of an acceleration voltage of 2.5 keV. Next, SF1 was calculated using the image processing apparatus and image processing software of the image analysis apparatus Luzex AP (manufactured by Nireco).

［評価結果］
表２より、本発明の範囲内である実施例１乃至１３については、キャリアによる色汚れもなく、また、画像濃度、キャリア付着、帯電変化量、抵抗低下量の全ての評価項目においても良好な結果が得られたことが判る。実施例のトナーは、初期から長期にわたり、クリーニング性に優れていた。一方、比較例１では、色汚れが発生し、実用上使用できない結果となった。また、比較例２のトナーは、初期からクリーニング不良が発生し、長期にわたる評価はできなかった。以上のように、実施例に示す現像剤を用いた画像形成技術により、極めて安定した良好な画質の画像を長期にわたって得ることができる。

[Evaluation results]
From Table 2, Examples 1 to 13 that are within the scope of the present invention are free from color smear due to the carrier, and are good in all evaluation items of image density, carrier adhesion, charge change amount, and resistance reduction amount. It turns out that the result was obtained. The toners of the examples were excellent in cleaning properties from the beginning to the long term. On the other hand, in Comparative Example 1, color stains occurred, and the results were not usable practically. Further, the toner of Comparative Example 2 was poorly cleaned from the beginning, and could not be evaluated for a long time. As described above, the image forming technique using the developer shown in the embodiment can provide a very stable and good-quality image over a long period of time.

  Although the embodiments of the present invention have been specifically described above, the present invention is not limited to these embodiments, and these embodiments of the present invention depart from the spirit and scope of the present invention. And can be changed or modified.

The schematic diagram which shows notionally the relationship between the particle diameter (Df) of an inorganic fine particle and the coating layer film thickness (h) in the coating layer of the carrier used for the electrophotographic developer of the present invention Schematic showing the configuration of a carrier resistance measuring device for measuring the volume resistivity of a carrier for an electrophotographic developer The block diagram which shows an example of the process cartridge in this invention The block diagram which shows an example of the process cartridge which showed the place which hold | maintains the electrophotographic developer in this invention

Explanation of symbols

1 Photoconductor (Photoconductor drum)
2 Developing device 3-3 staying developer 3a toner 3b magnetic carrier 4 developing sleeve 5 magnet roller 6 doctor blade 7 developer accommodating case 7a pre-doctor 8 toner hopper 8a toner replenishing port 9: toner transport and stirring paddle D developing area S developing Agent container 10 Process cartridge 11 Photoconductor 12 Charging means 13 Developing means 14 Cleaning means 20 Carrier surface 21 Inorganic fine particles 22 Core material 23 Cover layer 31 Cell 32a, 32b Electrode 33 Carrier 50 Charging roller 58 Cleaning device 80 Magnetic field forming means

Claims (10)

An electrophotographic developer comprising a toner and a carrier,
The toner contains a resin, a colorant, and a layered inorganic mineral in which at least a part of interlayer ions is modified with an organic ion, and at least an oil phase including a toner composition and / or a toner composition precursor, and / or Or a negatively chargeable toner having an average circularity of 0.925 to 0.970, which is formed by dispersing and / or emulsifying the monomer phase in an aqueous medium and granulating.
An electrophotographic developer, wherein the carrier has a core surface coated with a coating layer containing a binder resin, an ionic liquid, and inorganic fine particles. The ratio (W) of the inorganic fine particles to the core material is a range in which the coverage (C) by the inorganic fine particles to the core material represented by the following formula satisfies 50% or more,
Coverage (C) = (Ds × ρs × W) / (4 × Df × ρf) × 100
(However, Ds: Volume average particle diameter of core material, ρs: True specific gravity of core material, Df: Volume average particle diameter of inorganic fine particles, ρf: True specific gravity of inorganic fine particles)
The ratio (Df / h) between the volume average particle diameter (Df) of the inorganic fine particles and the film thickness (h) of the coating layer is 0.5 to 1.5. Electrophotographic developer. The electrophotographic developer according to claim 1, wherein the carrier has a volume resistivity of 10 ¹⁰ Ω · cm to 10 ¹⁶ Ω · cm.   The electrophotographic developer according to claim 1, wherein the carrier has a volume average particle diameter of 20 μm to 65 μm.   The electrophotographic developer according to any one of claims 1 to 4, wherein the binder resin contains at least a silicone resin.   6. The electrophotographic developer according to claim 5, wherein the binder resin is a mixed system of an acrylic resin and a silicone resin. The electrophotographic development according to any one of claims 1 to 6, wherein a magnetic moment in an applied magnetic field of 1 kOe (10 ³ / 4π · A / m) is 40 Am ² / kg to 90 Am ² / kg. Agent. A step of forming an electrostatic latent image on an image carrier, a step of developing the electrostatic latent image with a developer to form a visible image, a step of transferring the visible image to a recording member, A method of fixing a visible image transferred to a recording member,
The image forming method according to claim 1, wherein the developer is an electrophotographic developer according to claim 1. A photosensitive member that is detachably disposed on the main body of the image forming apparatus and forms an electrostatic latent image on the surface by exposure, a charging unit that charges the surface of the photosensitive member to form an electrostatic latent image, and is formed on the surface of the photosensitive member A process cartridge including at least a photosensitive member and a developing unit among a developing unit that develops an electrostatic latent image with a developer and a cleaning unit that removes dirt on the surface of the photosensitive member,
The process cartridge according to claim 1, wherein the developer is an electrophotographic developer according to claim 1.   At least a photoreceptor for forming an electrostatic latent image on the surface, developing means for converting the electrostatic latent image on the surface of the photoreceptor into a visible image using a developer, and transferring the visible image on the surface of the photoreceptor to a transfer material An electrophotographic development according to claim 1, wherein the image forming apparatus includes a transfer unit that performs fixing and a fixing unit that fixes a visible image on the transfer material. An image forming apparatus characterized by being an agent.

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