JP6473287B2 - Electrostatic latent image developing carrier, two-component developer and replenishment developer using the same, process cartridge including two-component developer, and image forming apparatus - Google Patents

Description

  The present invention relates to a carrier for developing an electrostatic latent image used in electrophotography and electrostatic recording, a two-component developer and a replenishment developer using the carrier, a process cartridge including the two-component developer, and an image forming apparatus. .

  In recent years, the toner has a small particle size for high quality output images, high temperature offset resistance, low temperature fixability for energy saving, and high temperature and high humidity during storage and transportation after production. High heat-resistant storage stability is required. In particular, since power consumption during fixing accounts for much of the power consumption in the image forming process, it is very important to improve low-temperature fixability.

  Conventionally, toner prepared by a kneading and pulverizing method has been used. The toner produced by the kneading and pulverization method is difficult to reduce the particle size, the shape is irregular and the particle size distribution is broad, so the quality of the output image is not sufficient, and the fixing energy is high. There were problems such as. In addition, when a wax (release agent) is added to improve the fixability, the toner produced by the kneading and pulverization method cracks at the interface of the wax during pulverization, so that a large amount of wax exists on the toner surface. Resulting in. For this reason, there is a problem in that, while the releasing effect is produced, the toner (filming) is likely to adhere to the carrier, the photoreceptor and the blade, and the overall performance is not satisfactory.

  Therefore, in order to overcome the above-mentioned problems caused by the kneading and pulverizing method, a toner manufacturing method by a polymerization method has been proposed. The toner produced by the polymerization method can be easily reduced in particle size, the particle size distribution is sharper than that of the toner produced by the pulverization method, and the release agent can be included. There is an advantage. The production method of the toner by the polymerization method includes a method for improving low-temperature fixability and high-temperature offset resistance, improvement of powder flowability and transferability when a small particle size toner is used, and heat-resistant storage stability. In addition, methods for the purpose of improving low-temperature fixability and high-temperature offset resistance have been developed and studied. However, the conventional technique cannot be said to be sufficient to satisfy the high level of low-temperature fixability required in recent years.

  Therefore, for the purpose of obtaining a high level of low-temperature fixability, a toner containing a crystalline polyester resin and a release agent, and a resin and wax that are incompatible with each other and having a sea-island phase separation structure has been proposed. (For example, Patent Document 1). In addition, a toner containing a crystalline polyester resin, a release agent, and a graft polymer has been proposed (for example, Patent Document 2). However, although these proposed technologies provide heat-resistant storage stability, high-temperature offset resistance, and a high level of low-temperature fixability, the dispersibility of the crystalline polyester resin and the release agent is not sufficient. There is a problem that will occur. In addition, although the toner added with these crystalline polyester resins is excellent in low-temperature fixability, it is inferior in the blocking property of the toner image after fixing, and when the printed matter on which the toner image is printed is stored at high temperature, There is a problem that fusion and peeling are likely to occur. Therefore, the present situation is that there is a demand for a toner having no filming and having excellent low-temperature fixability, high-temperature offset resistance, heat-resistant storage stability, and blocking resistance of a toner image after fixing.

  On the other hand, in the carrier, prevention of toner filming, formation of a uniform surface, prevention of surface oxidation, prevention of decrease in moisture sensitivity, extension of developer life, prevention of adhesion to the surface of the photoreceptor, photosensitivity For the purpose of protecting the body from scratches or wear, controlling the charge polarity, adjusting the charge amount, etc., the surface of the carrier core material is coated with a coating made of a resin having a low surface energy, such as a fluororesin or a silicone resin. Life has been extended.

Examples of carriers coated with a low surface energy resin include a carrier coated with a room temperature curable silicone resin and a positively chargeable nitrogen resin (see Patent Document 3), and a coating material containing at least one modified silicone resin. A carrier (see Patent Document 5), a carrier having a resin coating layer containing a room temperature curable silicone resin and a styrene / acrylic resin (see Patent Document 5), and the core particle surface is coated with two or more layers of silicone resin. Carrier (see Patent Document 6) in which there is no adhesion, Carrier in which silicone resin is applied in multiple layers on the surface of core particles (see Patent Document 7), Carrier whose surface is coated with a silicone resin containing silicon carbide (Patent Document 8) A positively chargeable carrier coated with a material exhibiting a critical surface tension of 20 dyn / cm or less (see Patent Document 9) , Such as a carrier coated with a coating material containing a fluorine alkyl acrylate (Patent Document 10) are known.
In addition, a coating liquid containing a siloxane-based material having a condensation-reactive silanol group or a precursor thereof (for example, a hydrolyzable group such as a halosilyl group or an alkoxysilyl group) is converted into a polysiloxane material using a titanium-based catalyst. It is known that a coating layer formed by condensation is provided on the surface of carrier core particles.
For example, Patent Document 11 discloses a material obtained by coating a silicone resin containing an organotitanium catalyst around core particles, and diisopropoxybis (acetylacetonate) is an example of a titanium catalyst. Tetraisopropoxytitanium, isopropoxy (2-ethylhexanediolato) titanium, bis (acryloyloxy) isopropoxyisostearoyloxytitanium, bis (2,4-pentanedionato) (1,3-propanedionate) They are listed as having the same effect as titanium.
Patent Document 12 discloses organopolysiloxane, organosilane, titanium (for example, tetraisopropoxy titanium), tin (for example, dibutyltin diacetate), zinc, cobalt, iron, aluminum-based compounds, and amines. There is disclosed a coating obtained by coating the surface of core material particles with a coating agent mainly composed of a coating composition comprising at least one curing catalyst selected from the group consisting of:
Patent Document 13 discloses a silicone resin or modified silicone resin in which the surface of the core material particle contains a quaternary ammonium salt catalyst, an aluminum catalyst, or a titanium catalyst (specifically, the diisopropoxybis (acetylacetonate)). What is coated with is disclosed.
Patent Document 14 discloses a radical having at least one functional group selected from the group consisting of an organopolysiloxane having a vinyl group at the terminal and a hydroxyl group, an amino group, an amide group, and an imide group on the magnetic particle surface. An electrostatic charge image developing carrier is disclosed in which a copolymer with a copolymerizable monomer is coated with a thermosetting resin crosslinked with an isocyanate compound.
Further, in Patent Document 15, in a dry two-component developer carrier having a resin coating layer on the surface of the core material, the friction charging ability of the coating layer is closer to the core material in the thickness direction of the resin coating layer. A carrier that is high and contains at least a silicone resin in the coating layer and has a different firing temperature in the thickness direction is disclosed.
Further, Patent Document 16 has a resin coating layer made of a silicone resin containing conductive fine particles on the surface of a carrier core material coated with a silane coupling agent, and the average particle diameter a of the conductive fine particles is 0. A carrier that is 15 to 0.5 μm and is equal to or more than b of the average thickness of the resin coating layer is disclosed.
Patent Document 17 discloses a coating resin layer containing a silicone resin containing conductive fine particles after the surface of a core material having an arithmetic average roughness Ra of 0.6 to 0.9 μm is coated with a silane coupling agent. A carrier for coating is disclosed.
Furthermore, Patent Document 18 discloses a filled ferrite carrier obtained by filling a void in a porous ferrite core material with a silicone resin containing an aminosilane coupling agent.

As described above, the life of the carrier has been extended by coating the surface of the core material particles constituting the carrier with a resin having a low surface energy, such as a fluororesin or a silicone resin.
However, in recent years, there has been a tendency for toner to be fixed at a low temperature in order to reduce power consumption, and in addition to an increase in printing speed, toner spent on the carrier is more likely to occur. In addition, toners tend to contain many additives in order to satisfy the demand for higher image quality, and these components are spent on the carrier to reduce the toner charge amount, allowance for toner scattering and background contamination. Is currently decreasing.
In a full-color electrophotographic system, carrier resistance and carrier charging ability when the toner spent on the carrier and the coating layer (coating) formed on the core particles constituting the carrier are scraped or peeled off ("scraping / peeling"). As a result, the amount of developer pumped up changes, causing problems such as the occurrence of abnormal images such as white spots and background stains due to the carrier adhering to the image area, fluctuations in image density, and toner scattering.
The present invention has been made in view of the above-described problems of the prior art, has characteristics capable of meeting the demand for low-temperature fixing, and has a toner spent property even for toners containing many additives. It is an object to provide a carrier that is suppressed and has excellent wear resistance (scraping / peeling) of a coating layer (coating film) formed on a carrier core material (core material particles).

As a result of intensive studies, the inventors of the present invention have configured the coating layer formed on the carrier core material (core material particles) as a constituent component of a binder resin, an aminosilane coupling agent, and fine particles, and the volume average particle diameter d of the fine particles. Is controlled to 500 nm or more and 900 nm or less, and is obtained by X-ray photoelectron spectroscopy (XPS) in the film thickness direction of the coating layer, and the N content on the outermost surface of the carrier and the N content in the depth direction d / 10 The inventors have found that the above problems can be solved by controlling the amount, and have reached the present invention.
That is, the above-described problem is a carrier for an electrostatic charge image developer having a coating layer containing at least a binder resin, an aminosilane coupling agent, and fine particles obtained by covering aluminum oxide with a conductive layer on core particles, The fine particles are surface-treated with the aminosilane coupling agent, the conductive layer contains tin, phosphorus or tungsten, and the fine particles have a volume average particle diameter d of 500 nm or more and 900 nm or less, and The N content ratio calculated by the following formula (1) based on the N content obtained by X-ray photoelectron spectroscopy (XPS) of the carrier is 100 / a when the content ratio of the fine particles is a weight%. This is solved by the carrier for developing an electrostatic latent image characterized by the above.
N content ratio = [N content in depth direction d / 10] / [N content on outermost surface of carrier] (1)
[N content: Carrier is filled into a 4mmφ hole, sputtered with Ar ions, and measured by XPS]

  The carrier for developing an electrostatic latent image according to the present invention has characteristics capable of meeting the demand for low-temperature fixing, and suppresses the toner spent property even for a toner containing many additives, and also has a carrier core. The coating layer (coating) formed on the material has excellent wear resistance (scraping / peeling).

It is a schematic diagram which shows the structural example of the process cartridge which concerns on this invention.

As described above, the electrostatic latent image developing carrier of the present invention has a static layer having a coating layer containing at least a binder resin, an aminosilane coupling agent, and fine particles obtained by covering aluminum oxide with a conductive layer on core particles. A carrier for a charge image developer, wherein the fine particles are surface-treated with the aminosilane coupling agent, the conductive layer contains tin and phosphorus or tungsten, and the volume average particle diameter d of the fine particles is The N content ratio calculated by the following formula (1) based on the N content obtained by X-ray photoelectron spectroscopy (XPS) of the carrier is 500 nm or more and 900 nm or less is the content ratio of the fine particles. When it is defined as a weight%, it is 100 / a or more.
N content ratio = [N content in depth direction d / 10] / [N content on outermost surface of carrier] (1)
[N content: Carrier is filled into a 4mmφ hole, sputtered with Ar ions, and measured by XPS]

The electrostatic latent image developing carrier of the present invention (hereinafter sometimes abbreviated as “carrier”) will be described in detail.
The carrier of the present invention has a coating layer on the carrier core material, and the coating layer contains fine particles as a component. It is extremely important that the volume average particle diameter d of the fine particles is 500 nm or more and 900 nm or less. That is, when fine particles are contained in the coating layer, unevenness due to the fine particles appears on the surface of the coating layer. The height of the irregularities appearing on the surface of the coating layer is determined by the size of the fine particles, and the larger the fine particles, the larger the irregularities on the surface.
As described above, low-temperature fixing is indispensable for toners in recent years, and with this low-temperature fixing property, the toner is easily deformed and melted due to stress due to friction with the carrier. Toner spent easily occurs. As the toner spent on the carrier advances, the exposed area of the carrier surface layer decreases and the ability to charge the toner decreases. As a result, the Q / M (Q is the toner charge amount and M is the toner weight) of the entire developer is reduced, and toner scattering and non-image area contamination (background contamination) are likely to occur.
However, by providing unevenness on the carrier surface layer, the toner spent tends to adhere to the concave portions of the carrier surface layer, and the convex portions become difficult to be spent due to friction between carriers. For this reason, when the height of the convex portion is sufficient, an exposed portion of the carrier surface layer can be secured even if toner spent occurs, so that a decrease in the charging ability of the developer can be minimized.
Here, when the volume average particle diameter d of the fine particles is less than 500 (nm), the carrier surface layer is not sufficiently uneven, and the entire carrier surface layer is covered with the toner spent, thereby sufficiently suppressing the decrease in charging ability of the developer. I can't. In addition, when the volume average particle diameter exceeds 900 (nm), the average particle diameter of the fine particles becomes too large with respect to the average particle diameter of the carrier, so that the fine particles are easily separated from the carrier, and the resistance of the carrier is reduced. Problems such as carrier adhesion are likely to occur.

The volume average particle diameter of the fine particles can be measured with an automatic particle size distribution analyzer CAPA-700 (manufactured by Horiba Seisakusho). As a pretreatment for the measurement, 300 ml of a toluene solution is added to 30 ml of aminosilane (SH6020: manufactured by Toray Dow Corning Silicone) 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 under the following measurement conditions.
[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: For the density of inorganic fine particles, enter the true specific gravity value measured using a dry automatic bulk density meter Accupic 1330 (manufactured by Shimadzu Corporation).

  The carrier coating layer of the present invention contains an aminosilane coupling agent as a component. And the N content ratio calculated by the formula (1) based on the N content obtained when the carrier is analyzed in the thickness direction of the coating layer by X-ray photoelectron spectroscopy (XPS) It is extremely important that the content ratio is 100% by weight or more, where the content ratio is a weight%. That is, the content of N in the lower layer, which is d / 10 in the depth direction, needs to be increased by 100 / a times or more with respect to the content of N on the outermost surface of the carrier.

As described above, by providing the carrier surface layer with sufficiently high irregularities, it is possible to minimize the decrease in developer charging ability even if toner spent occurs, but if the spent amount is very large It may not be enough.
Even when the reduction in charging capacity is not sufficiently suppressed as described above, charging is performed when the carrier surface layer is scraped by friction or the like by increasing the content of N in the lower layer relative to the content of N on the outermost surface of the carrier. The characteristics can be increased. In particular, the convex portions are easily scraped by friction between carriers, and the charging capability with time is easily increased by increasing the content of N in the lower layer relative to the content of N on the outermost surface of the carrier. For this reason, even if the charging ability of the concave portion of the carrier surface layer is reduced due to the toner spent, it is offset by the increase of the charging ability of the convex portion, and the charging ability of the developer can be kept constant. Further, the higher the content of the fine particles in the coating layer, the larger the area that is the convex portion of the carrier surface layer, and thus the effect of increasing the charging ability is greater.
Here, when the content of N in the lower layer of d / 10 does not increase 100 / a times or more in the depth direction with respect to the content of N on the outermost surface of the carrier, Since the charging capability cannot be sufficiently increased, the charging capability of the developer cannot be kept constant.

The N content ratio (= [N content on the outermost surface of the carrier] / [N content in the depth direction d / 10]) is calculated based on the N content obtained by XPS. The XPS measurement in the depth direction is performed while sequentially analyzing while cutting by sputtering. From the inventors' experience, it is considered that measurement under the following conditions is most desirable from the viewpoint of accuracy and reproducibility.
<XPS measurement conditions>
Measuring device: Axis-Ultra manufactured by Kratos
Measurement light source: Al (monochromator)
Measurement output: 150W (15kV 10mA)
Analysis area: 900 × 600μm ²
Measurement mode: Electrostatic mode Pass energy: (wide scan) 160eV (narrow scan) 40eV
Energy Step: (wide scan) 1.0eV (narrow scan) 0.2eV
Relative sensitivity coefficient: Uses the relative sensitivity coefficient of Kranos <Sputtering conditions>
Acceleration voltage / current: 3.5kV 20mA
AMPL: (1.6, 1.6)
Gas pressure: (STC) 3.0 × 10 ^-7 Pa
Sputtering rate: 3.16nm / min (SiO ₂ conversion)

  That is, quantitative analysis for each carrier thickness was performed under the above conditions. The depth in the depth direction can be inferred from the sputtering rate. All measurements in the present invention were performed at 0 seconds, 0.5 minutes, 5.5 minutes, 15.5 minutes, 35.5 minutes, and 55.5 minutes. Further, it was assumed that the linearity was established between the two points of the measurement, and the determination was made by plotting the average of the five sample measurements.

  In the present invention, the content ratio of the aminosilane coupling agent in the coating layer is preferably 1% by weight or more and 5% by weight or less. When the content ratio of the aminosilane coupling agent is less than 1% by weight, the N content in the XPS measurement in the depth direction is not easily inclined, and sufficient chargeability cannot be obtained for the entire carrier. On the other hand, when the content ratio exceeds 5% by weight, the charging capacity of the concave portion in the unevenness of the carrier surface layer becomes larger in the charging capacity of the entire carrier, so that the amount of charge decrease during toner spent becomes large and the developer charging It becomes difficult to keep the amount constant.

  The aminosilane coupling agent is not particularly limited, but r- (2-aminoethyl) aminopropyltrimethoxysilane, r- (2-aminoethyl) aminopropylmethyldimethoxysilane, N-β- (N-vinylbenzylamino) Ethyl) -r-aminopropyltrimethoxysilane hydrochloride, 3-aminopropylmethyldiethoxysilane, 3-aminopropyltrimethoxysilane, and the like, and two or more of them may be used in combination.

  In the present invention, the volume average particle diameter of the carrier is preferably 20 μm or more and 45 μm or less. When the volume average particle diameter of the carrier is less than 20 μm, the magnetization per particle is weakened, so that carrier adhesion may occur. On the other hand, if it exceeds 45 μm, the impact force when the carriers collide with each other increases, and the stress on the convex portion of the carrier surface layer increases, so that the convex portion of the carrier surface layer is sufficient due to embedding of the fine particles or scraping of the fine particles. It is difficult to maintain a constant charge amount of the developer during toner spent.

  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 can be used. Further, methanol is used for the dispersion, and the refractive index of methanol is set to 1.33, and the refractive indexes of the carrier and the core material are set to 2.42.

  In the present invention, the content ratio of the fine particles in the coating layer is preferably 50% by weight or more and 70% by weight or less. When the content of the fine particles is less than 50% by weight, it is difficult to keep the charging ability of the carrier constant during toner spent because the area of the convex portion of the carrier surface layer is not sufficient. On the other hand, when the content of the fine particles exceeds 70% by weight, the conductive fine particles in the resin layer are too much, so that the conductive fine particles are easily peeled off. A problem will occur.

  In the present invention, it is desirable to use conductive fine particles as the fine particles. The conductive fine particles are not particularly limited, but it is suitable to cover a certain amount of base particles such as aluminum oxide with a conductive layer such as tin oxide or ITO.

Examples of the white inorganic pigment used as the base particles of the conductive fine particles include commercially available titanium dioxide, aluminum oxide, silicon dioxide, zinc oxide, barium sulfate, zirconium oxide, alkali metal titanate, or muscovite. it can. In more detail, taking titanium dioxide as an example, the size of the particles is not limited, and even in the shape of a sphere, needle, etc., the crystal form is also anatase, rutile and amorphous. Can also be used.
Among these, the white inorganic pigment that is the core particle of the conductive fine particles is preferably aluminum oxide. Aluminum oxide can supply a charge that is not excessive or insufficient compared to other white inorganic pigments, and high image area ratio printing on low speed machines due to increased charge at low image area ratio printing density on high speed machines. Optimum charging can be obtained in a wide range up to charge reduction at density.

The conductive fine particles in the present invention can be produced by various methods, for example, obtained by uniformly depositing a tin salt hydrate layer containing a hydrate of phosphorus or tungsten salt on the surface of white inorganic pigment particles. It can manufacture by baking the covered layer.
In order to uniformly deposit a tin salt hydrate layer containing a hydrate of phosphorus or tungsten salt on the surface of the white inorganic pigment particles, for example, these phosphorus salts (for example, phosphorus pentoxide and POCl ₃ ) or tungsten salts (for example, , Tungsten chloride, tungsten oxychloride, sodium tungstate, tungstic acid, etc.) and tin salts (eg, tin chloride, tin sulfate, tin nitrate, etc., stannates such as sodium stannate, potassium stannate, tin, etc.) PH adjusting agent (for example, for depositing / depositing the dripped phosphorus or tungsten and tin on the pigment particle surface in the form of hydrate with an acidic aqueous liquid in which an organic tin compound such as an alkoxide is dissolved and contained) Base aqueous solution) in the aqueous solution in which the white inorganic pigment particles are dispersed. This can be carried out while preventing dissolution and surface alteration of the white inorganic pigment particles. At this time, the doping ratio of phosphorus or tungsten to SiO ₂ can be adjusted by adjusting the dropping amount of phosphorus or tungsten and the dropping amount of tin chloride solution. Of course, however, the isoelectric point of tin hydrate, ie, tin hydroxide or stannic acid, and the isoelectric point of phosphorus or Wangsten components are not necessarily the same, and the solubility of them at a specific pH is not necessarily different. It is preferable to pay attention to.

  In addition, for the purpose of reducing the aggressiveness of the white inorganic pigment particles during the dropping operation and the extreme hydration reaction of phosphorus or tungsten and tin and homogenizing the coating layer, for example, water-soluble substances such as methanol and methyl ethyl ketone are used. An organic solvent can be mixed and used. Firing of the obtained hydrate can be preferably performed at 300 to 850 ° C. in a non-oxidizing atmosphere, and as a result, the volume resistivity of the powder is very low compared to that heated in air. Can be suppressed.

  It is important that the powder specific resistance of the conductive fine particles is 2 to 15 (Ωcm). When the carrier is formed, the prescription amount of the conductive fine particles is determined with the aim of the resistance value. However, when the powder specific resistance is 2 (Ωcm) or less, the prescription amount decreases and the strength of the carrier film decreases. And it becomes fragile. On the other hand, when the powder specific resistance is 15 (Ωcm) or more, the amount of the prescription increases, so that there are too many conductive fine particles in the resin layer, so that the conductive fine particles are easily peeled off. The powder specific resistance of the conductive fine particles can be measured using, for example, an LCR meter (manufactured by Yokogawa Hewlett Packard).

In the present invention, the resin covering the surface of the core particle includes a repeating unit (A portion) represented by the following general formula (1) and a repeating unit (B portion) represented by the following general formula (2), A resin obtained by heat-treating an acrylic copolymer obtained by radical copolymerization is desirable.
Here, A part contains the monomer component (monomer A component) which produces | generates the repeating unit represented by General formula (1). Moreover, B part contains the monomer component (monomer B component) which produces | generates the repeating unit represented by General formula (2).

[In Formula (1), R ¹ represents a hydrogen atom or a methyl group, an R ² alkyl group having 1 to 4 carbon atoms, and m represents an integer of 1 to 8. X represents 10 to 90 mol%. ]

[In the formula (2), R ¹ represents a hydrogen atom or a methyl group, R ² represents an alkyl group having 1 to 4 carbon atoms, R ³ represents an alkyl group having 1 to 8 carbon atoms, or 1 to 1 carbon atoms. 4 represents an alkoxy group, and m represents an integer of 1 to 8. Y represents 10 to 90 mol%. ]

In said A part (and monomer A component), X = 10-90 mol%, Preferably it is 10-40 mol%, More preferably, it is 20-30 mol%.
The A portion (monomer A component) has an atomic group having many methyl groups in the side chain; tris (trimethylsiloxy) silane, and the ratio of the A portion (monomer A component) to the entire resin increases. The surface energy of the coating layer on the carrier core material (core material particles) is reduced, and adhesion of the resin component, wax component, etc. of the toner is reduced.
When the A portion (monomer A component) is less than 10 mol%, a sufficient surface energy reduction effect cannot be obtained, and the adhesion of the toner component increases rapidly. On the other hand, when the A part (monomer A component) is more than 90 mol%, the toughness due to the effect of the B part (monomer B component) is insufficient, and the adhesion between the core particles and the coating layer is reduced. The durability of the coating layer is deteriorated.

R ² in the general formulas (1) and (2) is an alkyl group having 1 to 4 carbon atoms, and the monomer A component that generates such an A moiety is not limited. Examples include tris (trialkylsiloxy) silane compounds represented by the following structural formulas (3) to (11).
In the following formulae, Me is a methyl group, Et is an ethyl group, and Pr is a propyl group.
_{CH 2 = CMe-COO-C} 3 H 6 -Si (OSiMe 3) 3 ··· (3)
_{CH 2 = CH-COO-C} 3 H 6 -Si (OSiMe 3) 3 ··· (4)
_{CH 2 = CMe-COO-C} 4 H 8 -Si (OSiMe 3) 3 ··· (5)
_{CH 2 = CMe-COO-C} 3 H 6 -Si (OSiEt 3) 3 ··· (6)
_{CH 2 = CH-COO-C} 3 H 6 -Si (OSiEt 3) 3 ··· (7)
_{CH 2 = CMe-COO-C} 4 H 8 -Si (OSiEt 3) 3 ··· (8)
_{CH 2 = CMe-COO-C} 3 H 6 -Si (OSiPr 3) 3 ··· (9)
_{CH 2 = CH-COO-C} 3 H 6 -Si (OSiPr 3) 3 ··· (10)
_{CH 2 = CMe-COO-C} 4 H 8 -Si (OSiPr 3) 3 ··· (11)

  The production method of the monomer component A for generating the A moiety is not particularly limited. For example, a method of reacting tris (trialkylsiloxy) silane with allyl acrylate or allyl methacrylate in the presence of a platinum catalyst; A method of reacting methacryloxyalkyltrialkoxysilane and hexaalkyldisiloxane in the presence of a carboxylic acid and an acid catalyst described in Japanese Patent No. 217389 can be applied.

The monomer B component (including the precursor) for generating the B moiety is a radically polymerizable bifunctional [when R ³ in the general formula (2) is an alkyl group] or a trifunctional [general formula ( When R ^{3 in} 2) is also an alkoxy group], Y = 10 to 90 mol%, preferably 10 to 80 mol%, more preferably 15 to 70 mol%. If the B component is less than 10 mol%, sufficient toughness cannot be obtained. On the other hand, when it exceeds 90 mol%, the coating becomes hard and brittle, and film scraping tends to occur. Moreover, environmental characteristics deteriorate. That is, it is conceivable that a large number of hydrolyzed cross-linking components remain as silanol groups and deteriorate the environmental characteristics (humidity dependency).

  As monomer B component, 3-methacryloxypropyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltriethoxysilane, 3-methacryloxypropylmethyldimethoxysilane , 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltri (isopropoxy) silane, and 3-acryloxypropyltri (isopropoxy) silane.

As a technology for improving durability by crosslinking a coating, Japanese Patent No. 3691115 discloses that the surface of magnetic particles is selected from the group consisting of an organopolysiloxane having a vinyl group at least at the terminal, a hydroxyl group, an amino group, an amide group, and an imide group. A carrier for developing an electrostatic charge image is described in which a copolymer with a radical copolymerizable monomer having at least one functional group is coated with a thermosetting resin crosslinked with an isocyanate compound. At present, sufficient durability against peeling or scraping (peeling or scraping) is not obtained.
The reason for this is not clear enough, but in the case of a thermosetting resin obtained by crosslinking the above-mentioned copolymer with an isocyanate compound, the isocyanate in the copolymer resin is understood from the structural formula. There are few functional groups (active hydrogen-containing groups such as amino group, hydroxy group, carboxy group, mercapto group, etc.) per unit weight that react (crosslink) with the compound, and two-dimensional or three-dimensional dense crosslinking at the crosslinking point Since the structure cannot be formed and the wear resistance of the coating is small, it is presumed that if the coating is used for a long time, the coating is easily peeled off or scraped off and sufficient durability is not obtained.
When the film is peeled off or scraped off, the image quality changes due to a decrease in carrier resistance and carrier adhesion occurs. Also, peeling or scraping of the coating reduces the fluidity of the developer and causes a decrease in the amount of pumping, resulting in a decrease in image density, background contamination due to TC increase, and toner scattering.

  The coating layer in the present invention contains, as a binder resin, a repeating unit (part A) represented by the general formula (1) and a repeating unit (part B) represented by the general formula (2), and a radical. A resin obtained by heat-treating an acrylic copolymer obtained by copolymerization is preferably used. Therefore, the resin used in the present invention is a copolymer resin having a large number of bifunctional or trifunctional crosslinkable functional groups (points) (2 to 3 times more per weight) than the resin unit weight. Since this is further cross-linked by condensation polymerization, the coating layer (coating) is extremely tough and difficult to scrape, and it is considered that high durability can be achieved.

  In addition, the crosslinking by the siloxane bond of the present invention has a higher binding energy and is more stable against heat stress than the crosslinking by the isocyanate compound as described in the above-mentioned Japanese Patent No. 3691115. It is inferred that the temporal stability of the layer (coating) is maintained.

  In the present invention, in order to impart sufficient flexibility and to improve the adhesion between the core material and the resin layer, and between the resin layer and the conductive fine particles, it is further represented by the following general formula (12). Repeating unit (C portion). Here, C part contains the monomer component (monomer C component) which produces | generates the repeating unit represented by General formula (12), what is called an acrylic component.

[In Formula (12), R ¹ represents a hydrogen atom or a methyl group, R ² represents an alkyl group having 1 to 4 carbon atoms, and Z represents 30 to 80 mol%. ]
That is, R ² is an aliphatic hydrocarbon group having 1 to 4 carbon atoms, and is a radical polymerizable acrylic compound having an acryloyl group or a methacryloyl group that is a methyl group, an ethyl group, a propyl group, and a butyl group. is there.

  As the contents of the component A and the component B in the copolymer resin when the component C is included, X is 10 to 40 mol%, Y is 10 to 40 mol%, and the content Z of the C component is 30 to 80 mol%, preferably 35 to 75 mol%, and 60 mol% <Y + Z <90 mol%, and more preferably 70 mol% <Y + Z <85 mol%.

  When the C portion (including the monomer C component) is larger than 80 mol%, either X or Y becomes 10 or less, so that the water repellency, hardness, and flexibility (film) of the carrier coating layer (film) It becomes difficult to achieve both (shaving).

  As the monomer C component for generating the C moiety, that is, the acrylic compound (monomer), acrylic acid ester and methacrylic acid ester are preferable. Specifically, methyl methacrylate, methyl acrylate, ethyl methacrylate, ethyl acrylate, butyl Methacrylate, butyl acrylate, 2- (dimethylamino) ethyl methacrylate, 2- (dimethylamino) ethyl acrylate, 3- (dimethylamino) propyl methacrylate, 3- (dimethylamino) propyl acrylate, 2- (diethylamino) ethyl methacrylate, 2 -(Diethylamino) ethyl acrylate and the like are exemplified. Of these, alkyl methacrylate is preferable, and methyl methacrylate is particularly preferable. One of these compounds may be used alone, or a mixture of two or more may be used.

The copolymer resin is an acrylic copolymer obtained by radical copolymerization of each monomer containing the A component and the B component, and has many crosslinkable functional groups per unit weight of the resin. Thus, since the crosslinking component B is subjected to condensation polymerization by heat treatment, the coating layer is considered to be extremely tough and difficult to scrape, so that high durability can be achieved.
In addition, since the crosslinking by the siloxane bond in the present invention has a larger binding energy and is more stable against heat stress than the crosslinking by the isocyanate compound as described in the aforementioned patent 3691115, the resin layer It is inferred that the stability over time is maintained.

  It is preferable that the binder resin composition constituting the coating layer further includes a silicone resin having a silanol group and / or a functional group capable of generating a silanol group by hydrolysis. Examples of the functional group capable of generating a silanol group by hydrolysis and / or hydrolysis include a negative group such as an alkoxy group or a halogeno group bonded to an Si atom, and such a functional group. The silicone resin having can be subjected to polycondensation directly with the crosslinking component B of the copolymer or with the crosslinking component B in a state of being changed to a silanol group. The toner spent property is further improved by adding a silicone resin component to the copolymer.

  The silicone resin having a silanol group and / or a functional group capable of generating a silanol group by hydrolysis used in forming the coating layer is at least a repeating unit represented by the following general formula (13). It is preferable to contain one.

[In Formula (13), A ¹ represents a hydrogen atom, a halogen atom, a hydroxy group, a methoxy group, a lower alkyl group having 1 to 4 carbon atoms, or an aryl group (such as a phenyl group or a tolyl group), and A ² represents carbon. A C 1-4 alkylene group or an arylene group (such as a phenylene group) is shown. ]

Carbon number of the aryl group in Formula (13) is 6-20, Preferably it is 6-14. This aryl group includes an aryl group derived from benzene (phenyl group), an aryl group derived from a condensed polycyclic aromatic hydrocarbon such as naphthalene, phenanthrene, and anthracene, and a chain polycyclic aromatic such as biphenyl and terphenyl. An aryl group derived from a group hydrocarbon is included. The aryl group may be substituted with various substituents.
The carbon number of the arylene group is 6 to 20, preferably 6 to 14. The arylene group includes an arylene group derived from benzene (phenylene group), an arylene group derived from a condensed polycyclic aromatic hydrocarbon such as naphthalene, phenanthrene, and anthracene, and a chain polycyclic aroma such as biphenyl and terphenyl. An arylene group derived from a group hydrocarbon is included. The arylene group may be substituted with various substituents.

A commercially available product can be used as the silicone resin having a functional group capable of generating a silanol group and / or a silanol group by hydrolysis. Such commercially available silicone resins are not particularly limited, but include KR251, KR271, KR272, KR282, KR252, KR255, KR152, KR155, KR211, KR216, KR213 (above, manufactured by Shin-Etsu Silicone), AY42-170, SR2510, SR2400, SR2406, SR2410, SR2405, SR2411 (manufactured by Toray Dow Corning Co., Ltd.) (manufactured by Toray Silicone Co., Ltd.) and the like.
As described above, various silicone resins can be used. Among them, methyl silicone resin is particularly preferable because of low toner spent property and small environmental fluctuation of charge amount.

  The weight average molecular weight of the silicone resin is 1,000 to 100,000, preferably 1,000 to 30,000. If the molecular weight of the resin used is greater than 100,000, the viscosity of the coating solution may increase excessively during coating, and the coating film uniformity may not be sufficiently obtained, or the density of the coating layer may not be sufficiently increased after curing. If it is less than 1,000, problems such as brittleness of the coating layer after curing tend to occur.

  The content ratio of the silicone resin is 5% to 95% by weight, preferably 10% to 60% by weight, based on the copolymer resin. If it is less than 5% by weight, the effect of improving the spent property and the like cannot be obtained.

  Further, as the binder resin composition constituting the coating layer, a resin other than the silicone resin having the silanol group and / or the hydrolyzable functional group can be contained. Such resin is not particularly limited, but acrylic resin, amino resin, polyvinyl resin, polystyrene resin, halogenated olefin resin, polyester, polycarbonate, polyethylene, polyvinyl fluoride, polyvinylidene fluoride, polytrifluoroethylene, Polyhexafluoropropylene, copolymers of vinylidene fluoride and vinyl fluoride, fluoroterpolymers such as terpolymers of tetrafluoroethylene, vinylidene fluoride, and non-fluorinated monomers, having silanol groups or hydrolyzable functional groups The silicone resin etc. which do not carry out are mentioned, You may use together 2 or more types. Among them, an acrylic resin is preferable because it has high adhesion to the core material particles and conductive fine particles and low brittleness.

  The acrylic resin preferably has a glass transition point of 20 to 100 ° C, more preferably 25 to 80 ° C. Since such an acrylic resin has an appropriate elasticity, when the developer is triboelectrically charged, a shock is applied to the resin layer due to the friction between the toner and the carrier or the friction between the carriers. It can be absorbed and deterioration of the resin layer and the conductive fine particles can be prevented.

  Further, the binder resin composition constituting the coating layer further preferably contains a crosslinked product of an acrylic resin and an amino resin. Thereby, fusion | melting of resin layers can be suppressed, maintaining moderate elasticity. The amino resin is not particularly limited, but a melamine resin and a benzoguanamine resin are preferable because the charge imparting ability of the carrier can be improved. Further, when it is necessary to appropriately control the charge imparting ability of the carrier, another amino resin may be used in combination with the melamine resin and / or benzoguanamine resin.

  As the acrylic resin capable of crosslinking with the amino resin, those having a hydroxyl group and / or a carboxyl group are preferable, and those having a hydroxyl group are more preferable. Thereby, adhesiveness with core material particle | grains or electroconductive fine particles can be improved, and the dispersion stability of electroconductive fine particles can also be improved. In this case, the acrylic resin preferably has a hydroxyl value of 10 mgKOH / g or more, and more preferably 20 mgKOH / g or more.

Moreover, in order to promote the condensation reaction of the said B part which is a crosslinking component, a titanium-type catalyst, a tin-type catalyst, a zirconium-type catalyst, and an aluminum-type catalyst can be used. Of these seed catalysts, titanium-based catalysts give excellent results, but titanium alkoxides and titanium chelates are particularly preferred.
This is presumably because the effect of accelerating the condensation reaction of the silanol group derived from the B portion, which is a crosslinking component, is large, and the catalyst is difficult to deactivate. Examples of the titanium alkoxide catalyst include titanium diisopropoxybis (ethyl acetoacetate) represented by the following structural formula (14). Examples of the titanium chelate catalyst include the following structural formula (15). And titanium diisopropoxybis (triethanolaminate) represented by

  The coating layer comprises a copolymer containing the A component and the B component, a titanium diisopropoxybis (ethylacetoacetate) catalyst, and if necessary, a resin other than the copolymer containing the A component and the B component. , A composition for a coating layer containing an aminosilane coupling agent, fine particles and a solvent. Specifically, it may be formed by condensing silanol groups while coating the core particles with the coating layer composition, or after coating the core particles with the resin layer composition, It may be formed by condensation.

  The method for condensing the silanol groups while coating the core particles with the coating layer composition is not particularly limited, but the core particles are coated with the resin layer composition while applying heat, light, etc. And the like. Further, the method of condensing the silanol group after coating the core material particles with the resin layer composition is not particularly limited, and examples thereof include a method of heating after coating the core material particles with the resin layer composition. .

  In general, a resin having a large molecular weight has a very high viscosity, and when applied to a substrate having a small particle size, it is easy to cause aggregation of the particles and non-uniformity of the resin layer, and it is extremely difficult to produce a coated carrier. Therefore, the weight average molecular weight of the copolymer resin used in the present invention is preferably 5,000 to 100,000, more preferably 10,000 to 70,000, and 30,000 to 40,000. More preferably it is. When the weight average molecular weight is less than 5,000, the strength of the resin layer is insufficient, and when it exceeds 100,000, the liquid viscosity becomes high and the carrier productivity is deteriorated.

  In the present invention, the coating layer has no film defects, and the average film thickness is preferably 0.30 to 0.90 μm. If the average film thickness is less than 0.30 μm, the coating layer is likely to be destroyed by use, and the film may be scraped. If the average film thickness exceeds 0.90 μm, the coating layer is not a magnetic substance, so that the carrier adheres to the image. May occur, and the resistance adjusting effect described later is not sufficiently exhibited.

  In the present invention, the core particle is not particularly limited as long as it is a magnetic substance, but is not limited to ferromagnetic metals such as iron and cobalt; iron oxides such as magnetite, hematite and ferrite; various alloys and compounds; Examples thereof include resin particles dispersed in the resin. Of these, Mn-based ferrite, Mn-Mg-based ferrite, Mn-Mg-Sr ferrite, and the like are preferable from the viewpoint of environmental considerations.

The two-component developer of the present invention (hereinafter sometimes abbreviated as “developer”) includes the carrier of the present invention and a color toner. The color toner (hereinafter sometimes abbreviated as “toner”) may be either monochrome or color. That is, the toner contains a binder resin and a colorant, and may be either a monochrome toner or a color toner.
Further, the toner particles may contain a release agent in order to be applied to an oilless system in which toner fixing prevention oil is not applied to the fixing roller. Such toner generally tends to cause filming. However, since the carrier of the present invention can suppress filming, a developer using the toner maintains good quality for a long period of time. be able to.
Further, color toners, particularly yellow toners, generally have a problem that color stains occur due to scraping of the coating layer of the carrier, but the developer of the present invention can suppress the occurrence of color stains.

  The toner can be produced using a known method such as a pulverization method or a polymerization method. For example, when a toner is manufactured using a pulverization method, first, a melt-kneaded product obtained by kneading a toner material is cooled, pulverized, and classified to prepare base particles. Next, in order to further improve transferability and durability, an external additive is added to the base particles to produce a toner.

  The apparatus for kneading the toner material is not particularly limited, but is a batch type two roll; a Banbury mixer; a KTK type twin screw extruder (manufactured by Kobe Steel), a TEM type twin screw extruder (manufactured by Toshiba Machine). Continuous twin-screw extruders such as a twin-screw extruder (manufactured by KCK), a PCM-type twin-screw extruder (manufactured by Ikekai Tekko), a KEX-type twin-screw extruder (manufactured by Kurimoto Iron Works); Examples thereof include a continuous single-screw kneader such as manufactured by Buss Co., Ltd.

Further, when the cooled melt-kneaded product is pulverized, it is roughly pulverized using a hammer mill, a rotoplex, etc., and then finely pulverized using a fine pulverizer using a jet stream, a mechanical pulverizer or the like. be able to. In addition, it is preferable to grind | pulverize so that an average particle diameter may be set to 3-15 micrometers.
Furthermore, when classifying the crushed melt-kneaded material, a wind classifier or the like can be used. In addition, it is preferable to classify so that the average particle diameter of the base particles is 5 to 20 μm.
In addition, when an external additive is added to the base particle, the external additive adheres to the surface of the base particle while being pulverized by mixing and stirring using a mixer.

The binder resin used for the toner material is not particularly limited, but is a homopolymer of styrene such as polystyrene, poly-p-styrene, polyvinyltoluene or the like; a styrene-p-chlorostyrene copolymer, a styrene-propylene copolymer. Polymer, styrene-vinyltoluene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-methacrylic acid copolymer, styrene-methyl methacrylate copolymer, styrene-methacrylic acid Ethyl copolymer, styrene-butyl methacrylate copolymer, styrene-α-chloromethyl methacrylate copolymer, styrene-acrylonitrile copolymer, styrene-vinyl methyl ether copolymer, styrene-vinyl methyl ketone copolymer , Styrene-butadiene copolymer, styrene -Styrene copolymers such as isoprene copolymer and styrene-maleic acid ester copolymer; polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polyester, polyurethane, epoxy resin, polyvinyl Examples include butyral, polyacrylic acid, rosin, modified rosin, terpene resin, phenol resin, aliphatic or aromatic hydrocarbon resin, aromatic petroleum resin, and the like.
The binder resin for pressure fixing is not particularly limited, but polyolefins such as low molecular weight polyethylene and low molecular weight polypropylene; ethylene-acrylic acid copolymer, ethylene-acrylic acid ester copolymer, styrene-methacrylic acid copolymer. Olefin copolymers such as ethylene-methacrylate copolymer, ethylene-vinyl chloride copolymer, ethylene-vinyl acetate copolymer, ionomer resin; epoxy resin, polyester, styrene-butadiene copolymer, polyvinylpyrrolidone, Examples thereof include methyl vinyl ether-maleic anhydride copolymer, maleic acid-modified phenol resin, phenol-modified terpene resin, and the like, and two or more of them may be used in combination.

  Colorants (pigments or dyes) used for the toner material are not particularly limited, but include cadmium yellow, mineral fast yellow, nickel titanium yellow, navel yellow, naphthol yellow S, Hansa Yellow G, Hansa Yellow 10G, Benzidine Yellow GR, Yellow pigments such as quinoline yellow lake, permanent yellow NCG and tartrazine lake; orange pigments such as molybdenum orange, permanent orange GTR, pyrazolone orange, vulcan orange, indanthrene brilliant orange RK, benzidine orange G, indanthrene brilliant orange GK ; Bengala, Cadmium Red, Permanent Red 4R, Resol Red, Pyrazolone Red, Watching Red Calcium Salt, Lake Red D, Red pigments such as Reliant Carmine 6B, Eosin Lake, Rhodamine Lake B, Alizarin Lake, Brilliant Carmine 3B; Purple Pigments such as Fast Violet B, Methyl Violet Lake; Cobalt Blue, Alkaline Blue, Victoria Blue Lake, Phthalocyanine Blue, No Metal Blue pigments such as phthalocyanine blue, phthalocyanine blue partially chlorinated, First Sky Blue, Indanthrene Blue BC; Green pigments such as chrome green, chromium oxide, pigment green B, malachite green lake; carbon black, oil furnace black, channel black Azine dyes such as lamp black, acetylene black and aniline black, black pigments such as metal salt azo dyes, metal oxides and composite metal oxides It is, may be used in combination of two or more thereof.

  The release agent used for the toner material is not particularly limited, but polyolefins such as polyethylene and polypropylene, fatty acid metal salts, fatty acid esters, paraffin wax, amide wax, polyhydric alcohol wax, silicone varnish, carnauba wax, ester wax. Etc., and two or more of them may be used in combination.

  Further, a charge control agent may be further contained as a toner material. The charge control agent is not particularly limited, but nigrosine; an azine dye having an alkyl group having 2 to 16 carbon atoms (see Japanese Patent Publication No. 42-1627); I. Basic Yellow 2 (C.I. 41000), C.I. I. Basic Yellow 3, C.I. I. Basic Red 1 (C.I. 45160), C.I. I. Basic Red 9 (C.I. 42500), C.I. I. Basic Violet 1 (C.I. 42535), C.I. I. Basic Violet 3 (C.I. 42555), C.I. I. Basic Violet 10 (C.I. 45170), C.I. I. Basic Violet 14 (C.I. 42510), C.I. I. Basic Blue 1 (C.I. 42025), C.I. I. Basic Blue 3 (C.I. 51005), C.I. I. Basic Blue 5 (C.I. 42140), C.I. I. Basic Blue 7 (C.I. 42595), C.I. I. Basic Blue 9 (C.I. 52015), C.I. I. Basic Blue 24 (C.I. 52030), C.I. I. Basic Blue 25 (C.I. 52025), C.I. I. Basic Blue 26 (C.I. 44045), C.I. I. Basic Green 1 (C.I. 42040), C.I. I. Basic dyes such as Basic Green 4 (C.I. 42000); lake pigments of these basic dyes; I. Solvent Black 8 (C.I. 26150), quaternary ammonium salts such as benzoylmethylhexadecyl ammonium chloride and decyltrimethyl chloride; dialkyltin compounds such as dibutyl and dioctyl; dialkyltin borate compounds; guanidine derivatives; vinyl having an amino group Polyamine resins such as polycondensation polymers and condensation polymers having amino groups; described in JP-B-41-20153, JP-B-43-27596, JP-B-44-6397, and JP-B-45-26478 Metal complex salts of monoazo dyes; salicylic acids described in JP-B-55-42752 and JP-B-59-7385; dialkylsalicylic acid, naphthoic acid, dicarboxylic acid Zn, Al, Co, Cr, Fe, etc. Metal complexes of Examples thereof include honed copper phthalocyanine pigments; organic boron salts; fluorine-containing quaternary ammonium salts; calixarene compounds, and the like. For color toners other than black, white metal salts of salicylic acid derivatives are preferred.

  The external additive externally added to the toner base particles is not particularly limited, but inorganic particles such as silica, titanium oxide, alumina, silicon carbide, silicon nitride, boron nitride; average particle diameter obtained by the soap-free emulsion polymerization method Examples thereof include resin particles such as 0.05 to 1 μm polymethyl methacrylate particles and polystyrene particles, and two or more kinds may be used in combination. Among these, metal oxide particles such as silica and titanium oxide whose surfaces are hydrophobized are preferable. Furthermore, by using a combination of hydrophobized silica and hydrophobized titanium oxide, the amount of added hydrophobized titanium oxide is higher than that of hydrophobized silica. A toner having excellent charging stability can be obtained.

  By applying the carrier of the present invention to a replenishment developer composed of a carrier and a toner and applying it to an image forming apparatus that forms an image while discharging excess developer in the developing device, a stable image can be obtained over a very long period of time. Quality is obtained. That is, the deteriorated carrier in the developing device and the non-deteriorated carrier in the replenishing developer are replaced, and the charge amount is kept stable over a long period of time, so that a stable image can be obtained. This method is particularly effective when printing a large image area. When printing a large image area, carrier charge deterioration due to toner spent on the carrier is the main carrier deterioration. However, when this method is used, the carrier replenishment amount increases when the image area is large, and the deteriorated carrier is replaced. Increases frequency. Thereby, a stable image can be obtained for an extremely long period of time.

  The mixing ratio of the replenishment developer is preferably 2 to 50 parts by mass of toner with respect to 1 part by mass of the carrier. When the amount of toner is less than 2 parts by mass, the amount of replenishment carrier is excessive, the carrier is excessively supplied, and the carrier concentration in the developing device becomes too high, so that the charge amount of the developer tends to increase. Further, when the developer charge amount increases, the developing ability decreases and the image density decreases. On the other hand, if the amount exceeds 50 parts by mass, the carrier ratio in the replenishment developer decreases, so that the replacement of carriers in the image forming apparatus decreases, and the effect on carrier deterioration cannot be expected.

The process cartridge of the present invention comprises an electrostatic latent image carrier, a charging member for charging the surface of the electrostatic latent image carrier, and an electrostatic latent image formed on the electrostatic latent image carrier. It has a developing part that develops using a developer, and a cleaning member that cleans the electrostatic latent image carrier. FIG. 1 shows an example of the process cartridge of the present invention.
In FIG. 1, an electrostatic latent image carrier [photoconductor] (11), a charging device (12) for charging the photoconductor (11), and a photoconductor (11) are formed on a process cartridge (10). The electrostatic latent image is developed using the developer of the present invention to form a toner image, and the toner image formed on the photoreceptor (11) is transferred to a recording medium, and then the photoreceptor ( 11) A cleaning device (14) for removing the toner remaining on the surface is integrally supported. The process cartridge (10) is detachable from the main body of an image forming apparatus such as a copying machine or a printer.

  The image forming apparatus according to the present invention includes an electrostatic latent image carrier, a charging unit that charges the latent image carrier, an exposure unit that forms an electrostatic latent image on the latent image carrier, and the electrostatic latent image. Developing means for developing the electrostatic latent image formed on the image carrier using a developer to form a toner image, and transferring the toner image formed on the electrostatic latent image carrier to a recording medium Transfer means, and fixing means for fixing the toner image transferred to the recording medium, and other means appropriately selected as necessary, for example, static elimination means, cleaning means, recycling means, control The developer of the present invention is used as a developer.

That is, as the image forming method in the present invention, the step of forming an electrostatic latent image on the electrostatic latent image carrier and the electrostatic latent image formed on the electrostatic latent image carrier are used as the developer of the present invention. And developing the toner image to form a toner image, transferring the toner image formed on the electrostatic latent image carrier to a recording medium, and fixing the toner image transferred to the recording medium. What has is used preferably.
Hereinafter, a method for forming an image using the image forming apparatus equipped with the process cartridge (10) will be described.
First, the photosensitive member (11) is rotationally driven at a predetermined peripheral speed, and the charging device (12) uniformly charges the peripheral surface of the photosensitive member (11) to a predetermined positive or negative potential. Next, exposure light is irradiated onto the peripheral surface of the photoreceptor (11) from an exposure apparatus (not shown) such as a slit exposure type exposure apparatus or an exposure apparatus that performs scanning exposure with a laser beam, and electrostatic latent images are sequentially formed. The Further, the electrostatic latent image formed on the peripheral surface of the photoconductor (11) is developed by the developing device (13) using the developer of the present invention to form a toner image. Next, the toner image formed on the peripheral surface of the photoconductor (11) is synchronized with the rotation of the photoconductor (11), and the photoconductor (11) and the transfer device (not shown) are fed from the paper feed unit (not shown). ) Are sequentially transferred onto the transfer paper fed during (). Further, the transfer paper onto which the toner image has been transferred is separated from the peripheral surface of the photoreceptor (11), introduced into a fixing device (not shown) and fixed, and then copied as a copy (copy) of the image forming apparatus. Printed out. On the other hand, after the toner image is transferred, the surface of the photoconductor (11) is cleaned by the cleaning device (14) to remove the remaining toner, and then the charge is removed by a static eliminator (not shown). Used for image formation.

  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. “Parts” represents parts by weight.

(Manufacture example 1 of core particle)
MnCO ₃ , Mg (OH) ₂ , Fe ₂ O ₃ , and SrCO ₃ powder were weighed and mixed to obtain a mixed powder. This mixed powder was calcined in a heating furnace at 850 ° C. for 1 hour in the air atmosphere, and the obtained calcined product was cooled and pulverized to obtain a powder having a particle size of 3 μm or less. This powder was made into a slurry by adding 1 wt% of a dispersant together with water, and the slurry was supplied to a spray dryer and granulated to obtain a granulated product having an average particle size of about 41 μm. This granulated product was loaded into a firing furnace and fired at 1120 ° C. for 4 hours in a nitrogen atmosphere. The obtained fired product was pulverized with a pulverizer, and the particle size was adjusted by sieving to obtain spherical ferrite particles 1 (core material particles 1) having a volume average particle size of about 36 μm. It was subjected to component analysis of the core particles 1, MnO: 40.0mol%, MgO : 10.0mol%, Fe 2 O 3: 50mol%, SrO: was 0.4 mol%.

(Structural example 2 of core particle)
Spherical ferrite particles 2 having a volume average particle size of about 20 μm (core material particles) in the same manner as in Production Example 1 except that the average particle size of the granulated product from the slurry was about 24 μm in Production Example 1 of the core material particles. 2) was obtained.

(Manufacture example 3 of core material particles)
Spherical ferrite particles 3 having a volume average particle size of about 45 μm are the same as those of Core Material Production Example 1 except that the average particle size of the granulated product from the slurry is adjusted to about 50 μm in the adjustment of Production Example 1 of the core material particles. (Core particle 3) was obtained.

(Manufacture example 4 of core particle)
Spherical ferrite particles 4 having a volume average particle size of about 18 μm are the same as those of Core Material Production Example 1 except that the average particle size of the granulated product from the slurry was adjusted to about 22 μm in the preparation of Core Material Production Example 1. (Core particle 4) was obtained.

(Manufacture example 5 of core particle)
Spherical ferrite particles 5 having a volume average particle size of about 47 μm are the same as those of Core Material Production Example 1 except that the average particle size of the granulated product from the slurry is adjusted to about 53 μm in the adjustment of Production Example 1 of the core material particles. (Core particle 5) was obtained.

(Manufacture example 6 of core particle)
MnCO ₃ , Mg (OH) ₂ , and Fe ₂ O ₃ powder were weighed and mixed to obtain a mixed powder. This mixed powder was calcined in a heating furnace at 900 ° C. for 3 hours in an air atmosphere, and the obtained calcined product was cooled and pulverized to obtain a powder having a particle diameter of approximately 2 μm. This powder was made into a slurry by adding 1 wt% of a dispersant together with water, and the slurry was supplied to a spray dryer and granulated to obtain a granulated product having an average particle size of about 41 μm. This granulated product was loaded into a firing furnace and fired at 1250 ° C. for 5 hours in a nitrogen atmosphere. The obtained fired product was pulverized with a pulverizer, and the particle size was adjusted by sieving to obtain spherical ferrite particles (core material particles 6) having a volume average particle size of about 36 μm. Was subjected to component analysis of the core particles 6, MnO: 46.2mol%, MgO : 0.7mol%, Fe 2 O 3: was 53 mol%.

(Production Example 1 of Conductive Fine Particles)
100 g of aluminum oxide (AKP-30 manufactured by Sumitomo Chemical Co., Ltd.) was dispersed in 1 liter of water to form a suspension, and this liquid was heated to 65 ° C. To the suspension, 155 g of stannic chloride and 4.65 g of phosphorus pentoxide dissolved in 1 liter of 2N hydrochloric acid and 12% by weight aqueous ammonia for 3 hours so that the pH of the suspension is 7-8. It was dripped over 6 minutes. After dropping, the cake obtained by filtering and washing the suspension was dried at 110 ° C. Next, this dry powder was treated in a nitrogen stream at 500 ° C. for 5 hours to obtain conductive fine particles 1. The obtained conductive fine particles 1 had a volume average particle diameter of 600 nm and a powder specific resistance of 6 Ω · cm.

(Production example 2 of conductive fine particles)
In the conductive fine particle production example 1, a volume average particle diameter of 500 nm and a powder specific resistance of 23Ω are exactly the same as in the production example 1 except that 80 g of stannic chloride and 2.4 g of phosphorus pentoxide are dropped over 1 hour and 36 minutes. A conductive fine particle 2 of cm was obtained.

(Production Example 3 of Conductive Fine Particles)
100 g of aluminum oxide (AKP-20 manufactured by Sumitomo Chemical Co., Ltd.) was dispersed in 1 liter of water to form a suspension, and this liquid was heated to 65 ° C. To this suspension, a solution of 498 g of stannic chloride and 14.94 g of phosphorus pentoxide dissolved in 1 liter of 2N hydrochloric acid and 12 wt% aqueous ammonia was added so that the suspension had a pH of 7-8. The solution was added dropwise over a period of 58 minutes. After dropping, the cake obtained by filtering and washing the suspension was dried at 110 ° C. Next, this dry powder was treated in a nitrogen stream at 500 ° C. for 5 hours to obtain conductive fine particles 3. The obtained conductive fine particles 3 had a volume average particle diameter of 900 nm and a powder specific resistance of 4 Ω · cm.

(Production Example 4 of Conductive Fine Particles)
In the adjustment of the conductive fine particle production example 1, the volume average particle diameter is 450 nm, the powder ratio is exactly the same as in the production example 1 except that 52 g of stannic chloride and 1.56 g of phosphorus pentoxide are dropped over 1 hour and 2 minutes. Conductive fine particles 4 having a resistance of 63 Ω · cm were obtained.

(Production Example 5 of Conductive Fine Particles)
100 g of aluminum oxide (AKP-20 manufactured by Sumitomo Chemical Co., Ltd.) was dispersed in 1 liter of water to form a suspension, and this liquid was heated to 65 ° C. To this suspension, a solution of 601 g of stannic chloride and 18.03 mg of phosphorus pentoxide dissolved in 1 liter of 2N hydrochloric acid and 12 wt% aqueous ammonia was added for 12 hours 1 so that the pH of the suspension would be 7-8. It was added dropwise over a period of minutes. After dropping, the cake obtained by filtering and washing the suspension was dried at 110 ° C. Next, this dry powder was treated in a nitrogen stream at 500 ° C. for 5 hours to obtain conductive particles 5. The obtained conductive particles 5 had a volume average particle size of 950 nm and a powder specific resistance of 3 Ω · cm.

(Binder Resin Synthesis Example 1)
300 g of toluene was charged into a flask equipped with a stirrer, and the temperature was raised to 90 ° C. under a nitrogen gas stream. Next, CH ₂ = CMe—COO—C ₃ H ₆ —Si (OSiMe ₃ ) ₃ [wherein Me is a methyl group. ] 8-4 g (200 mmol: Silaplane, TM-0701T / manufactured by Chisso Corporation), 3-methacryloxypropylmethyldiethoxysilane 39 g (150 mmol), A mixture of 65.0 g (650 mmol) of methyl methacrylate and 0.58 g (3 mmol) of 2,2′-azobis-2-methylbutyronitrile was added dropwise over 1 hour. After completion of the dropwise addition, a solution prepared by dissolving 0.06 g (0.3 mmol) of 2,2′-azobis-2-methylbutyronitrile in 15 g of toluene was further added (2,2′-azobis-2-methylbutyrate). The total amount of ronitrile (0.64 g = 3.3 mmol) was mixed at 90 to 100 ° C. for 3 hours and radical copolymerized to obtain methacrylic copolymer 1. The resulting methacrylic copolymer 1 had a weight average molecular weight of 33,000.
Subsequently, it diluted with toluene so that the non volatile matter of this methacrylic copolymer solution might be 25 weight%. The viscosity of the copolymer solution thus obtained was 8.8 mm ² / s, and the specific gravity was 0.91.
In addition, the weight average molecular weight was calculated | required in standard polystyrene conversion using the gel permeation chromatography. The viscosity was measured at 25 ° C. according to JIS-K2283. The non-volatile content was calculated according to the following formula by weighing 1 g of the coating composition in an aluminum dish and measuring the weight after heating at 150 ° C. for 1 hour.
Non-volatile content (%) = (weight before heating−weight after heating) × 100 / weight before heating

[Example 1]
(Manufacture of carrier 1)
(Preparation of coating layer forming solution)
A coating layer forming solution was prepared based on the following formulation. First, aminosilane, conductive fine particles 1 and toluene are dispersed with a homomixer for 3 minutes, and then the remaining raw materials excluding the titanium catalyst are added and dispersed with a paint shaker for 1 hour together with 1000 parts of 0.5 mm Zr beads, and then meshed. Then, the beads were removed and allowed to stand for 10 minutes to obtain a coating layer forming solution.
<Prescription of coating layer forming solution>
-Methacrylic copolymer 1 (solid content 25 wt%): 54.0 parts by weight-Silicone resin solution [solid content 20 wt%
(SR2410: manufactured by Toray Dow Corning Silicone Co.)]: 582 parts by weight Titanium catalyst [solid content: 95% by weight (TC-750:
Matsumoto Fine Chemical Co., Ltd.)]: 15.7 parts by weight Aminosilane [100 wt% solid content
(SH6020: manufactured by Toray Dow Corning Silicone Co.)]: 10.8 parts by weight-Conductive fine particles 1: 200 parts by weight-Toluene: 800 parts by weight [Carrier]
[Spherical ferrite particle 1 (core material particle 1)]: 5000 parts by weight as the core material particles, and a solution obtained by adding a titanium catalyst to the coating layer forming solution is applied to the surface of the core material particles using a Spira coater (manufactured by Okada Seiko Co., Ltd.). ) At a coater temperature of 70 ° C. and dried. The obtained dried body (ferrite powder bulk) was baked by standing at 240 ° C. for 1 hour in an electric furnace under a nitrogen atmosphere. After cooling, the ferrite powder bulk was crushed using a sieve having an aperture of 63 μm to obtain [Carrier 1] having a volume average particle size of 36 μm.
The N content ratio calculated by analyzing the N content in the depth direction of the carrier by X-ray photoelectron spectroscopy (XPS) of the carrier 1 (= [N content on the outermost surface of the carrier] / [in the depth direction d / 10) The N content]) was 2.00. On the other hand, the content ratio a of the conductive fine particles was 56.2% by weight, and the N content ratio of the carrier 1 was 100 / a (= 1.78) or more. In the present invention, it is essential that the N content ratio is larger than 100 / a.
In addition, the value of 100 / a shows the numerical value which rounded off three decimal places. The same applies to the following embodiments.
The XPS measurement method and measurement conditions are the same as described above. Sputtering was performed by irradiating Ar ions obliquely upward from 45 degrees because the detector was in the sample vertical direction. Since Ar ions are sufficiently smaller than the carrier, the upper part of the carrier can be cut off.
Regarding the N content ratio of carrier 1 and the content ratio of conductive fine particles, the volume average particle diameter (600 nm) of fine particles, the volume average particle diameter of carrier (36 μm), and the content ratio of aminosilane (3.0 wt%) are listed below. 1 is shown collectively.

[Example 2]
(Manufacture of carrier 2)
[Carrier 1] having a volume average particle size of 36 μm is the same as [Example 1] except that the conductive fine particles 1 (200 parts by weight) are changed to the conductive fine particles 2 (200 parts by weight) in the production of the carrier 1. 2] was obtained.
The N content ratio of Carrier 2 was 1.83. On the other hand, the content ratio a of the conductive fine particles was 56.2% by weight, and the N content ratio of the carrier 2 was 100 / a (= 1.78) or more.
Regarding the N content ratio of carrier 2 and the content ratio of conductive fine particles, the volume average particle diameter (500 nm) of fine particles, the volume average particle diameter of carrier (36 μm), and the content ratio of aminosilane (3.0 wt%) are listed below. 1 is shown collectively.

[Example 3]
(Manufacture of carrier 3)
[Carrier 1] having a volume average particle size of 36 μm is the same as [Example 1] except that the conductive fine particles 1 (200 parts by weight) are changed to the conductive fine particles 3 (200 parts by weight) in the production of the carrier 1. 3] was obtained.
The N content ratio of Carrier 3 was 2.50. On the other hand, the content ratio a of the conductive fine particles was 56.2% by weight, and the N content ratio of the carrier 3 was 100 / a (= 1.78) or more.
Regarding the N content ratio of carrier 3 and the content ratio of conductive fine particles, the volume average particle diameter of fine particles (900 nm), the volume average particle diameter of carrier (36 μm), and the content ratio of aminosilane (3.0 wt%) are listed below. 1 is shown collectively.

[Example 4]
(Manufacture of carrier 4)
[Carrier 4] having a volume average particle size of 36 μm is the same as [Example 1] except that the amount of aminosilane (10.8 parts by weight) is changed to 3.5 parts by weight in the production of Carrier 1. Got.
The N content ratio of Carrier 4 was 2.00. On the other hand, the content ratio a of the conductive fine particles was 57.4% by weight, and the N content ratio of the carrier 4 was 100 / a (= 1.74) or more.
Regarding the N content ratio of carrier 4 and the content ratio of conductive fine particles, the volume average particle diameter of fine particles (600 nm), the volume average particle diameter of carrier (36 μm), and the content ratio of aminosilane (1.0 wt%) are shown in the following table. 1 is shown collectively.

[Example 5]
(Manufacture of carrier 5)
[Carrier 5] having a volume average particle size of 36 μm is exactly the same as [Example 1] except that the amount of aminosilane (10.8 parts by weight) is changed to 18.3 parts by weight in the production of Carrier 1. Got.
The N content ratio of Carrier 5 was 2.22. On the other hand, the content ratio a of the conductive fine particles was 55.1% by weight, and the N content ratio of the carrier 5 was 100 / a (= 1.82) or more.
Regarding the N content ratio of carrier 5 and the content ratio of conductive fine particles, the volume average particle diameter (600 nm) of fine particles, the volume average particle diameter of carrier (36 μm), and the content ratio of aminosilane (5.0 wt%) are listed below. 1 is shown collectively.

[Example 6]
(Manufacture of carrier 6)
[Carrier 6] having a volume average particle size of 36 μm was the same as in [Example 1] except that the amount of aminosilane (10.8 parts by weight) was changed to 1.0 part by weight in the production of Carrier 1. Got.
The N content ratio of the carrier 6 was 2.00. On the other hand, the content ratio a of the conductive fine particles was 57.8% by weight, and the N content ratio of the carrier 6 was 100 / a (= 1.73) or more.
Regarding the N content ratio of carrier 6 and the content ratio of conductive fine particles, the volume average particle diameter (600 nm) of fine particles, the volume average particle diameter of carrier (36 μm), and the content ratio of aminosilane (0.3 wt%) are shown in the following table. 1 is shown collectively.

[Example 7]
(Manufacture of carrier 7)
[Carrier 7] having a volume average particle size of 36 μm is the same as in [Example 1] except that the amount of aminosilane (10.8 parts by weight) is changed to 22.0 parts by weight in the production of Carrier 1. Got.
The N content ratio of the carrier 7 was 2.09. On the other hand, the content ratio a of the conductive fine particles was 54.5% by weight, and the N content ratio of the carrier 7 was 100 / a (= 1.83) or more.
Regarding the N content ratio of carrier 7 and the content ratio of conductive fine particles, the volume average particle diameter (600 nm) of fine particles, the volume average particle diameter of carrier (36 μm), and the content ratio of aminosilane (6.0 wt%) are shown in the following table. 1 is shown collectively.

[Example 8]
(Manufacture of carrier 8)
[Carrier 8] having a volume average particle size of 36 μm was produced in the same manner as in [Example 1], except that the prescription amount (200 parts by weight) of the conductive fine particles 1 was changed to 156 parts by weight in the production of the carrier 1. Obtained.
The N content ratio of the carrier 8 was 2.00. On the other hand, the content ratio a of the conductive fine particles was 50.1% by weight, and the N content ratio of the carrier 8 was 100 / a (= 2.00 [rounded off 1.996]) or more.
Regarding the N content ratio of carrier 8 and the content ratio of conductive fine particles, the volume average particle size (600 nm) of fine particles, the volume average particle size of carrier (36 μm), and the content ratio of aminosilane (3.5 wt%) are shown in the following table. 1 is shown collectively.

[Example 9]
(Manufacture of carrier 9)
[Carrier 9] having a volume average particle size of 36 μm was produced in the same manner as in [Example 1] except that the formulation amount (200 parts by weight) of the conductive fine particles 1 was changed to 362 parts by weight in the production of carrier 1. Obtained.
The N content ratio of the carrier 9 was 2.17. On the other hand, the content ratio a of the conductive fine particles was 69.9% by weight, and the N content ratio of the carrier 9 was 100 / a (= 1.43) or more.
Regarding the N content ratio of carrier 9 and the content ratio of conductive fine particles, the volume average particle diameter (600 nm) of fine particles, the volume average particle diameter of carrier (36 μm), and the content ratio of aminosilane (2.1 wt%) are shown in the following table. 1 is shown collectively.

[Example 10]
(Manufacture of carrier 10)
[Carrier 10] having a volume average particle size of 36 μm was produced in the same manner as in [Example 1], except that the prescription amount (200 parts by weight) of conductive fine particles 1 was changed to 150 parts by weight in the production of carrier 1. Obtained.
The N content ratio of the carrier 10 was 2.40. On the other hand, the content ratio a of the conductive fine particles was 49.1% by weight, and the N content ratio of the carrier 10 was 100 / a (= 2.04) or more.
Regarding the N content ratio of carrier 10 and the content ratio of conductive fine particles, the volume average particle diameter of fine particles (600 nm), the volume average particle diameter of carrier (36 μm), and the content ratio of aminosilane (3.5 wt%) are shown in the following table. 1 is shown collectively.

[Example 11]
(Manufacture of carrier 11)
[Carrier 11] having a volume average particle diameter of 36 μm was produced in the same manner as in [Example 1] except that the prescription amount (200 parts by weight) of conductive fine particles 1 was changed to 380 parts by weight in the production of carrier 1. Obtained.
The N content ratio of the carrier 11 was 2.33. On the other hand, the content ratio a of the conductive fine particles was 70.9% by weight, and the N content ratio of the carrier 11 was 100 / a (= 1.41) or more.
Regarding the N content ratio of carrier 11 and the content ratio of conductive fine particles, the volume average particle diameter (600 nm) of fine particles, the volume average particle diameter of carrier (36 μm), and the content ratio of aminosilane (2.0 wt%) are shown in the following table. 1 is shown collectively.

[Example 12]
(Manufacture of carrier 12)
In the production of the carrier 1, the volume average particle size of 20 μm is exactly the same as in Example 1 except that the spherical ferrite particles 1 (core material particles 1) are changed to spherical ferrite particles 2 (core material particles 2). [Carrier 12] was obtained.
The N content ratio of the carrier 12 was 2.17. On the other hand, the content ratio a of the conductive fine particles was 56.2% by weight, and the N content ratio of the carrier 12 was 100 / a (= 1.78) or more.
Regarding the N content ratio of carrier 12 and the content ratio of conductive fine particles, the volume average particle diameter (600 nm) of fine particles, the volume average particle diameter of carrier (20 μm), and the content ratio of aminosilane (3.0 wt%) are listed below. 1 is shown collectively.

[Example 13]
(Manufacture of carrier 13)
In the production of the carrier 1, the volume average particle diameter of 45 μm is exactly the same as in Example 1 except that the spherical ferrite particles 1 (core material particles 1) are changed to spherical ferrite particles 3 (core material particles 3). [Carrier 13] was obtained.
The N content ratio of the carrier 13 was 2.00. On the other hand, the content ratio a of the conductive fine particles was 56.2% by weight, and the N content ratio of the carrier 13 was 100 / a (= 1.78) or more.
Regarding the N content ratio of carrier 13 and the content ratio of conductive fine particles, the volume average particle diameter (600 nm) of fine particles, the volume average particle diameter of carrier (45 μm), and the content ratio of aminosilane (3.0 wt%) are shown in the following table. 1 is shown collectively.

[Example 14]
(Manufacture of carrier 14)
In the production of the carrier 1, the volume average particle size of 18 μm is the same as in Example 1 except that the spherical ferrite particles 1 (core material particles 1) are changed to spherical ferrite particles 4 (core material particles 4). [Carrier 14] was obtained.
The N content ratio of the carrier 14 was 2.17. On the other hand, the content ratio a of the conductive fine particles was 56.2% by weight, and the N content ratio of the carrier 14 was 100 / a (= 1.78) or more.
Regarding the N content ratio of carrier 14 and the content ratio of conductive fine particles, the volume average particle diameter (600 nm) of fine particles, the volume average particle diameter of carrier (18 μm), and the content ratio of aminosilane (3.0 wt%) are shown in the following table. 1 is shown collectively.

[Example 15]
(Manufacture of carrier 15)
In the production of the carrier 1, the volume average particle size of 47 μm is exactly the same as in Example 1 except that the spherical ferrite particles 1 (core material particles 1) are changed to spherical ferrite particles 5 (core material particles 5). [Carrier 15] was obtained.
The N content ratio of the carrier 15 was 2.00. On the other hand, the content ratio a of the conductive fine particles was 56.2% by weight, and the N content ratio of the carrier 15 was 100 / a (= 1.78) or more.
Regarding the N content ratio of carrier 15 and the content ratio of conductive fine particles, the volume average particle diameter (600 nm) of fine particles, the volume average particle diameter of carrier (47 μm), and the content ratio of aminosilane (3.0 wt%) are shown in the following table. 1 is shown collectively.

[Example 16]
(Manufacture of carrier 16)
In the production of the carrier 1, the conductive fine particles 1 (200 parts by weight) produced in the conductive fine particle production example 1 [using aluminum oxide (AKP-30 manufactured by Sumitomo Chemical)] were used as the conductive fine particle production example 3 [aluminum oxide. [Carrier 16] having a volume average particle size of 36 μm was exactly the same as [Example 1] except that the conductive fine particles 3 (200 parts by weight) produced in (Use of AKP-20 manufactured by Sumitomo Chemical) were used. Obtained.
The N content ratio of the carrier 16 was 2.80. On the other hand, the content ratio a of the conductive fine particles was 56.2% by weight, and the N content ratio of the carrier 16 was 100 / a (= 1.78) or more.
Regarding the N content ratio of carrier 16 and the content ratio of conductive fine particles, the volume average particle diameter (500 nm) of fine particles, the volume average particle diameter of carrier (36 μm), and the content ratio of aminosilane (3.0 wt%) are listed below. 1 is shown collectively.

[Example 17]
(Manufacture of carrier 17)
(Preparation of coating layer forming solution)
A coating layer forming solution was prepared based on the following formulation. First, aminosilane, conductive fine particles 1 and toluene are dispersed with a homomixer for 3 minutes, and then the remaining raw materials excluding the titanium catalyst are added and dispersed with a paint shaker for 1 hour together with 1000 parts of 0.5 mm Zr beads, and then meshed. Then, the beads were removed and allowed to stand for 10 minutes to obtain a coating film forming solution.
<Prescription of coating layer forming solution>
・ Silicon resin solution [solid content 20% by weight
(SR2410: manufactured by Toray Dow Corning Silicone)]: 649 parts by weight Titanium catalyst [solid content 95% by weight
(TC-750: manufactured by Matsumoto Fine Chemical Co.)] 15.7 parts by weight Aminosilane [solid content: 100% by weight
(SH6020: manufactured by Toray Dow Corning Silicone Co.)] 10.8 parts by weight-Conductive fine particles 1: 200 parts by weight-Toluene: 800 parts by weight [Carrier]
[Spherical ferrite particle 1 (core material particle 1)]: 5000 parts by weight as the core material particles, and a solution obtained by adding a titanium catalyst to the coating layer forming solution is applied to the surface of the core material particles using a Spira coater (manufactured by Okada Seiko Co., Ltd.). ) At a coater temperature of 70 ° C. and dried. The obtained dried body (ferrite powder bulk) was baked by standing at 240 ° C. for 1 hour in an electric furnace under a nitrogen atmosphere. After cooling, the ferrite powder bulk was crushed using a sieve having an aperture of 63 μm to obtain [Carrier 17] having a volume average particle size of 36 μm.
The N content ratio of the carrier 17 was 2.00. On the other hand, the content ratio a of the conductive fine particles was 56.3 wt%, and the N content ratio of the carrier 17 was 100 / a (= 1.78) or more.
Regarding the N content ratio of carrier 17 and the content ratio of conductive fine particles, the volume average particle diameter (600 nm) of fine particles, the volume average particle diameter of carrier (36 μm), and the content ratio of aminosilane (3.0 wt%) are shown in the following table. 1 is shown collectively.

[Example 18]
(Manufacture of carrier 18)
A volume average particle size of 36 μm was produced in the same manner as in [Example 1] except that the spherical ferrite particles 1 (core material particles 1) were changed to spherical ferrite particles 6 (core material particles 6) in the production of the carrier 1. [Carrier 18] was obtained.
The N content ratio of the carrier 18 was 2.00. On the other hand, the content ratio a of the conductive fine particles was 56.2% by weight, and the N content ratio of the carrier 18 was 100 / a (= 1.78) or more.
Regarding the N content ratio of carrier 18 and the content ratio of conductive fine particles, the volume average particle diameter (600 nm) of fine particles, the volume average particle diameter of carrier (36 μm), and the content ratio of aminosilane (3.0 wt%) are shown in the following table. 1 is shown collectively.

[Comparative Example 1]
(Manufacture of carrier 19)
[Carrier 1] having a volume average particle size of 36 μm is the same as in [Example 1] except that the conductive fine particles 1 (200 parts by weight) are changed to the conductive fine particles 4 (200 parts by weight). 19].
The N content ratio of the carrier 19 was 1.83. On the other hand, the content ratio a of the conductive fine particles was 56.2% by weight, and the N content ratio of the carrier 19 was 100 / a (= 1.78) or more.
Regarding the N content ratio of carrier 19 and the content ratio of conductive fine particles, the volume average particle diameter (450 nm) of fine particles, the volume average particle diameter of carrier (36 μm), and the content ratio of aminosilane (3.0 wt%) are shown in the following table. 1 is shown collectively.

[Comparative Example 2]
(Manufacture of carrier 20)
[Carrier 1] having a volume average particle size of 36 μm is the same as [Example 1] except that the conductive fine particles 1 (200 parts by weight) are changed to the conductive fine particles 5 (200 parts by weight) in the production of the carrier 1. 20].
The N content ratio of the carrier 20 was 2.50. On the other hand, the content ratio a of the conductive fine particles was 56.2% by weight, and the N content ratio of the carrier 20 was 100 / a (= 1.78) or more.
Regarding the N content ratio of carrier 20 and the content ratio of conductive fine particles, the volume average particle diameter (950 nm) of fine particles, the volume average particle diameter of carrier (36 μm), and the content ratio of aminosilane (3.0 wt%) are shown in the following table. 1 is shown collectively.

[Comparative Example 3]
(Manufacture of carrier 21)
(Coating layer)
A coating layer forming solution was prepared based on the same formulation as in Example 2. However, unlike the preparation of Example 2, all the raw materials except for the titanium catalyst were added simultaneously and dispersed with a homomixer for 5 minutes to obtain a coating layer forming solution.
[Carrier]
[Spherical ferrite particle 1 (core material particle 1)]: 5000 parts by weight as the core material particles, and a solution obtained by adding a titanium catalyst to the coating layer forming solution is applied to the surface of the core material particles using a Spira coater (manufactured by Okada Seiko Co., Ltd.). ) And then dried at a coater internal temperature of 60 ° C. The obtained dried body (ferrite powder bulk) was fired in an electric furnace in a nitrogen atmosphere 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 21] having a volume average particle size of 36 μm.
The N content ratio of the carrier 21 was 1.50. On the other hand, the content ratio a of the conductive fine particles was 56.2% by weight, and the N content ratio of the carrier 21 was smaller than 100 / a (= 1.78).
Regarding the N content ratio of carrier 21 and the content ratio of conductive fine particles, the following table is shown together with the volume average particle size (500 nm) of fine particles, the volume average particle size of carrier (36 μm), and the content ratio of aminosilane (3.0 wt%). 1 is shown collectively.

[Comparative Example 4]
(Manufacture of carrier 22)
(Coating layer)
A coating layer forming solution was prepared based on the same formulation as in Example 3. However, unlike the preparation of Example 3, all the raw materials except for the titanium catalyst were added simultaneously and dispersed for 5 minutes with a homomixer to obtain a coating layer forming solution.
[Carrier]
[Spherical ferrite particle 1 (core material particle 1)]: 5000 parts by weight as the core material particles, and a solution obtained by adding a titanium catalyst to the coating layer forming solution is applied to the surface of the core material particles using a Spira coater (manufactured by Okada Seiko Co., Ltd.). ) And then dried at a coater internal temperature of 60 ° C. The obtained dried body (ferrite powder bulk) was fired in an electric furnace in a nitrogen atmosphere 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 22] having a volume average particle size of 36 μm.
The N content ratio of the carrier 22 was 1.67. On the other hand, the content ratio a of the conductive fine particles was 56.2% by weight, and the N content ratio of the carrier 22 was smaller than 100 / a (= 1.78).
Regarding the N content ratio of carrier 22 and the content ratio of conductive fine particles, the volume average particle diameter of fine particles (900 nm), the volume average particle diameter of carrier (36 μm), and the content ratio of aminosilane (3.0 wt%) are shown in the following table. 1 is shown collectively.

[Production of Toner 1]
Materials necessary for the production of toner 1 were synthesized and prepared as follows.
-Synthesis of polyester resin A-
Into a reaction vessel equipped with a cooling tube, a stirrer and a nitrogen introduction tube, 65 parts of a 2-mole addition product of ethylene oxide of bisphenol A, 86 parts of a 3-mole addition product of propion oxide of bisphenol A, 274 parts of terephthalic acid and 2 parts of dibutyltin oxide And reacted at 230 ° C. for 15 hours under normal pressure. Next, it was made to react under reduced pressure of 5-10 mmHg for 6 hours, and the polyester resin was synthesize | combined. The obtained polyester resin A has a number average molecular weight (Mn) of 2,300, a weight average molecular weight (Mw) of 8,000, a glass transition temperature (Tg) of 58 ° C., an acid value of 25 mgKOH / g, and a hydroxyl value of It was 35 mgKOH / g.

-Synthesis of styrene acrylic resin A-
Into a reaction vessel equipped with a cooling tube, a stirrer and a nitrogen introduction tube, 300 parts of ethyl acetate, 185 parts of styrene, 115 parts of acrylic monomer and 5 parts of azobisisobutylnitrile were added, and the temperature was 65 ° C. (atmospheric pressure). ) For 8 hours. Next, 200 parts of methanol was added and stirred for 1 hour, and then the supernatant was removed and dried under reduced pressure to synthesize styrene-acrylic resin A. The obtained styrene acrylic resin A had Mw of 20,000 and Tg of 58 ° C.

-Synthesis of prepolymer (polymer capable of reacting with active hydrogen group-containing compound)-
In a reaction vessel equipped with a cooling tube, a stirrer and a nitrogen introduction tube, 682 parts by mass of bisphenol A ethylene oxide 2 mol adduct, 81 parts by mass of bisphenol A propylene oxide 2 mol adduct, 283 parts by mass of terephthalic acid, trimellitic anhydride 22 parts by mass and 2 parts by mass of dibutyltin oxide were charged and reacted at 230 ° C. for 8 hours under normal pressure. Subsequently, it was made to react under reduced pressure of 10-15mHg for 5 hours, and the intermediate polyester was synthesize | combined.
The obtained intermediate polyester has a number average molecular weight (Mn) of 2,100, a weight average molecular weight (Mw) of 9,600, a glass transition temperature (Tg) of 55 ° C., an acid value of 0.5, and a hydroxyl value of 49.

Next, 411 parts by mass of the intermediate polyester, 89 parts by mass of isophorone diisocyanate, and 500 parts by mass of ethyl acetate were charged in a reaction vessel equipped with a cooling pipe, a stirrer, and a nitrogen introduction pipe, and reacted at 100 ° C. for 5 hours. Thus, a prepolymer (polymer capable of reacting with the active hydrogen group-containing compound) was synthesized.
The free isocyanate content of the obtained prepolymer was 1.60% by mass, and the solid content concentration of the prepolymer (after standing at 150 ° C. for 45 minutes) was 50% by mass.

-Synthesis of ketimine (the active hydrogen group-containing compound)-
In a reaction vessel equipped with a stir bar and a thermometer, 30 parts by mass of isophoronediamine and 70 parts by mass of methyl ethyl ketone were charged and reacted at 50 ° C. for 5 hours to synthesize a ketimine compound (the active hydrogen group-containing compound). The amine value of the obtained ketimine compound (the active hydrogen machine-containing compound) was 423.

-Preparation of master batch-
1,000 parts of water, DBP oil absorption 42 mL / 100 g, pH 9.5 carbon black Printex 35 (Degussa) 540 parts, and 1,200 parts of polyester resin A, Henschel mixer (Mitsui Mining) And mixed. Next, the obtained 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.

-Preparation of aqueous medium-
Aqueous medium was prepared by mixing and stirring 306 parts of ion-exchanged water, 265 parts of a 10% by mass suspension of tricalcium phosphate, and 1.0 part of sodium dodecylbenzenesulfonate, and dissolving them uniformly.

-Measurement of critical micelle concentration-
The critical micelle concentration of the surfactant was measured by the following method. Surface tension meter Sigma (KSV
Analysis was performed using an analysis program in the Sigma system. Surfactant was added dropwise by 0.01 wt% with respect to the aqueous medium, and the interfacial tension after stirring and standing was measured. From the obtained surface tension curve, the surfactant concentration at which the interfacial tension did not decrease even when the surfactant was dropped was calculated as the critical micelle concentration. When the critical micelle concentration of sodium dodecylbenzenesulfonate with respect to the aqueous medium was measured with a surface tension meter Sigma, it was 0.05 wt% with respect to the weight of the aqueous medium.

-Preparation of toner material liquid-
In a beaker, 70 parts of polyester resin A, 10 parts by weight of prepolymer and 100 parts of ethyl acetate were added and dissolved by stirring. As a release agent, 5 parts of paraffin wax (HNP-9 melting point 75 ° C., manufactured by Nippon Seiki Co., Ltd.), 2 parts of MEK-ST (Nissan Chemical Industry Co., Ltd.), and 10 parts of masterbatch were added. After 3 passes under the condition that the liquid feeding speed is 1 kg / hour, the peripheral speed of the disk is 6 m / second, and 80% by volume of zirconia beads having a particle diameter of 0.5 mm are filled, the ketimine 2.7 is used. A part by mass was added and dissolved to prepare a toner material solution.

―Preparation of emulsion or dispersion―
150 parts by mass of the aqueous medium phase is placed in a container, and stirred at a rotational speed of 12,000 rpm using a TK homomixer (manufactured by Tokushu Kika Kogyo Co., Ltd.), and 100 parts by mass of the solution or dispersion of the toner material is added thereto. The mixture was added and mixed for 10 minutes to prepare an emulsified dispersion (emulsified slurry).

―Removal of organic solvent―
100 parts by mass of the emulsified slurry was charged into a Kolben equipped with a stirrer and a thermometer, and the solvent was removed at 30 ° C. for 12 hours while stirring at a stirring peripheral speed of 20 m / min.

-Washing-
After 100 parts by mass of the dispersion slurry was filtered under reduced pressure, 100 parts by mass of ion-exchanged water was added to the filter cake, mixed with a TK homomixer (10 minutes at a rotational speed of 12,000 rpm), and then filtered. To the obtained filter cake, 300 parts by mass of ion-exchanged water was added, mixed with a TK homomixer (10 minutes at 12,000 rpm), and then filtered twice. To the obtained filter cake, 20 parts by mass of a 10% by mass aqueous sodium hydroxide solution was added, mixed with a TK homomixer (30 minutes at 12,000 rpm), and then filtered under reduced pressure. To the obtained filter cake, 300 parts by mass of ion-exchanged water was added, mixed with a TK homomixer (at 12,000 rpm for 10 minutes), and then filtered. To the obtained filter cake, 300 parts by mass of ion-exchanged water was added, mixed with a TK homomixer (10 minutes at 12,000 rpm), and then filtered twice. Furthermore, 20 mass parts of 10 mass% hydrochloric acid was added to the obtained filter cake, mixed with a TK homomixer (at a rotation speed of 12,000 rpm for 10 minutes) and then filtered.

-Surfactant adjustment-
To the filter cake obtained by the above washing, 300 parts by mass of ion-exchanged water was added, and the electrical conductivity of the toner dispersion was measured by mixing with a TK homomixer (10 minutes at 12,000 rpm). The surfactant concentration of the toner dispersion was calculated from a calibration curve for surfactant concentration prepared in advance. From this value, ion-exchanged water was added so that the surfactant concentration was the target surfactant concentration of 0.05 wt%, and a toner dispersion was obtained.

―Surface treatment process―
The toner dispersion liquid adjusted to the predetermined surfactant concentration was heated for 10 hours at a heating temperature T1 = 55 ° C. in a water bath while mixing at 5000 rpm with a TK homomixer. Thereafter, the toner dispersion was cooled to 25 ° C. and filtered. Further, 300 parts by mass of ion-exchanged water was added to the obtained filter cake, mixed with a TK homomixer (10 minutes at 12,000 rpm), and then filtered.

―Dry―
The obtained final filter cake was dried with a circulating dryer at 45 ° C. for 48 hours, and sieved with an opening of 75 μm mesh to obtain toner base particles 1.

―External treatment―
Further, with respect to 100 parts by weight of toner base particles 1, 3.0 parts by weight of hydrophobic silica having an average particle diameter of 100 nm, 0.5 parts by weight of titanium oxide having an average particle diameter of 20 nm, and hydrophobicity having an average particle diameter of 15 nm. 1.5 parts of silica fine powder was mixed with a Henschel mixer to obtain [Toner 1].

<Create developer>
930 parts by weight of each of [Carrier 1] to [Carrier 21] obtained in Examples 1 to 8 and Comparative Examples 1 to 3 and 70 parts by weight of toner 1 were mixed, and turbulent mixer was used for 5 minutes at 81 rpm. Stirring was carried out to prepare evaluation developers 1 to 21, respectively.
The replenishment developer was prepared using the carrier and the toner so that the toner concentration was 900% by mass.

  Using the obtained developer, developer characteristic evaluation 1 [Evaluation by measuring the amount of change in the charge amount of the carrier after each initial and 100,000 sheets running at an image area ratio of 40% and 100%] and development Agent characteristic evaluation 2 [Measurement of charge amount of carrier after initial and 1 million runnings at 0.5% image area ratio and evaluation of carrier adhesion after running 1 million sheets] was performed. The evaluation results are shown in Table 2 below.

<Developer property evaluation 1>
Using the developer thus obtained, image evaluation was performed using RICOH Pro C901 (Ricoh Digital Color Copier / Printer Multifunction Machine). Specifically, first, using the developers 1 to 21 of Examples and Comparative Examples, the charge amount of the carrier after the initial and 100,000 sheets of running was measured at an image area ratio of 40%, and the change of the charge amount was measured. The amount was calculated. Further, the charge amount of the carrier after initial and 100,000 running was measured at an image area ratio of 100%, and the change amount of the charge amount was calculated.
The initial charge amount of the carrier is determined by using a blow-off device TB-200 (manufactured by Toshiba Chemical Co., Ltd.) by mixing the carrier 1 to 21 and the toner 1 at a weight ratio of 93: 7 and frictionally charging the sample. It was measured. The charge amount of the carrier after running 100,000 sheets was measured in the same manner as above except that the carrier from which the toner of each color in the developer after running was removed using a blow-off device. The initial charge amount was evaluated according to the following criteria.
30.0 to less than 40.0: ◎ (very good)
25.0 or more and less than 30.0, or 40.0 or more and less than 45.0: ○ (good)
20.0 or more and less than 25.0, or 45.0 or more and less than 50.0: Δ (usable)
Less than 20.0, or 50.0 or more: x (defect)
In addition, the Q / M (toner charge amount, Q: toner charge amount, M: toner weight) difference between the initial and 100,000 sheets was evaluated according to the following criteria.
0 or more and less than 5.0: ◎ (very good)
5.0 or more and less than 10.0: ○ (good)
10.0 to less than 15.0: △ (can be used)
15.0 or more: x (defect)

<Developer property evaluation 2>
Using the developer thus obtained, image evaluation was performed using RICOH Pro C901 (Ricoh Digital Color Copier / Printer Multifunction Machine). Specifically, first, using the developers 1 to 21 of Examples and Comparative Examples, measurement of the charge amount of the carrier after initial and 1,000,000 sheets of running and 1 million sheets with an image area ratio of 0.5%. The carrier adhesion after running was evaluated.
The initial charge amount of the carrier is determined by using a blow-off device TB-200 (manufactured by Toshiba Chemical Co., Ltd.) by mixing the carrier 1 to 21 and the toner 1 at a mass ratio of 93: 7 and friction charging the sample. It was measured. The charge amount of the carrier after running 1 million sheets was measured in the same manner as above except that the carrier from which the toner of each color in the developer after running was removed using a blow-off device. The Q / M difference after the initial and 1 million sheets was evaluated according to the following criteria.
0 or more but less than 5.0: ◎ (very good)
5.0 or more and less than 10.0: ○ (good)
10.0 to less than 15.0: △ (available)
15.0 or more: × (defect)

The carrier adhesion (solid portion) was evaluated by the following method.
・ Development gap (photosensitive member-developing sleeve): 0.3 mm
・ Doctor gap (developing sleeve-doctor): 0.65mm
-Photoconductor linear velocity: 440 mm / sec
(Development sleeve linear velocity) / (photosensitive member linear velocity): 1.80
-Write density: 600 dpi
・ Charging potential (Vd): -600V
-Potential after exposure of the portion corresponding to the image portion (solid document): -100V
・ Development bias: DC-500V

The number of carriers attached to a solid image (30 mm × 30 mm) of RICOH Pro C901 under the above-described development conditions was counted on the photoconductor to evaluate the solid carrier adhesion.
The symbols described in the table are ◎: very good, ○: good, Δ: usable, ×: poor.
The physical properties of the developer are shown in Table 1, and the developer evaluation results are shown in Table 2.

From the results of Table 2, the volume average particle diameter d of the fine particles constituting the coating layer is 500 nm or more and 900 nm or less, and in the depth direction d / 10 with respect to the outermost surface of the carrier obtained by X-ray photoelectron spectroscopy (XPS). All of the carriers (Examples 1 to 18) of the present invention having an N content ratio of 100 / a (content ratio% of fine particles) or more have very good or usable properties.
On the other hand, in the case of Comparative Example 1 (450 nm) in which the volume average particle diameter d of the fine particles was less than 500 nm, defects occurred in the charging stability evaluation after outputting 100,000 sheets with a 100% image area ratio.
Further, in the case of Comparative Example 2 (950 nm) in which the volume average particle diameter d exceeds 900 nm, defects occurred in the carrier adhesion evaluation after outputting 1 million sheets with an image area ratio of 0.5%. Further, in the case of Comparative Example 3 in which the N content ratio (1.50) in the depth direction d / 10 is smaller than 100 / a (1.78), after outputting 100,000 sheets at a 100% image area ratio In both the charging stability evaluation and the carrier adhesion evaluation after outputting 1 million sheets at an image area ratio of 0.5%, defects occurred. In the case of Comparative Example 4 in which the volume average particle diameter d is 900 nm and the N content ratio (1.67) in the depth direction d / 10 is smaller than 100 / a (1.78), A defect occurred in both the charging stability evaluation after outputting 1 million sheets at the% image area ratio and the carrier adhesion evaluation.
As described above, the carrier of the present invention has characteristics that can meet the demand for low-temperature fixing, and suppresses the toner spent property even on a toner containing many additives, and on the core material particles. The formed coating layer has excellent wear resistance (scraping / peeling). That is, the carrier of the present invention is used for continuous paper passing at a printing density of a high image area ratio using a toner that has been easily spent due to low-temperature fixing or a toner that contains a large amount of additives for high image quality. Is excellent in charging stability and can maintain high image quality over a long period of time. By using the carrier of the present invention, a highly reliable two-component developer and replenishment developer, a process cartridge including the two-component developer, and an image forming apparatus can be provided.

10 Process cartridge 11 Electrostatic latent image carrier [photosensitive member]
12 Charging device 13 Developing device 14 Cleaning device

JP 2004-46095 A JP 2007-271789 A Japanese Patent Laid-Open No. 55-127469 Japanese Patent Laid-Open No. 55-157751 JP-A-56-140358 JP-A-57-96355 JP 57-96356 A JP 58-207054 A JP-A-61-1110161 JP-A-62-273576 JP 2001-92189 A Japanese Patent Laid-Open No. 06-222621 JP 2006-337828 A Japanese Patent No. 3691115 Japanese Patent No. 3439587 JP 2012-177873 A JP 2012-189880 A JP 2012-215875 A

Claims (10)

A carrier for an electrostatic charge image developer having a coating layer containing at least a binder resin, an aminosilane coupling agent, and fine particles obtained by covering aluminum oxide with a conductive layer on core particles,
The fine particles are surface-treated with the aminosilane coupling agent,
The conductive layer includes tin and phosphorus or tungsten,
The volume average particle diameter d of the fine particles is 500 nm or more and 900 nm or less, and the N content calculated by the following formula (1) based on the N content obtained by X-ray photoelectron spectroscopy (XPS) of the carrier A carrier for developing an electrostatic latent image, wherein the ratio is 100 / a or more when the content ratio of the fine particles is a weight%.
N content ratio = [N content in depth direction d / 10] / [N content on outermost surface of carrier] (1)
[N content: Carrier is filled into a 4mmφ hole, sputtered with Ar ions, and measured by XPS]   2. The electrostatic latent image developing carrier according to claim 1, wherein the content ratio of the aminosilane coupling agent in the coating layer is 1% by weight or more and 5% by weight or less.   3. The electrostatic latent image developing carrier according to claim 1, wherein the content ratio “a” of the fine particles in the coating layer is 50% by weight or more and 70% by weight or less.   4. The electrostatic latent image developing carrier according to claim 1, wherein the fine particles are conductive fine particles. An acrylic resin obtained by radical copolymerization, wherein the binder resin includes a repeating unit (A portion) represented by the following general formula (1) and a repeating unit (B portion) represented by the general formula (2). The carrier for developing an electrostatic latent image according to any one of claims 1 to 4, wherein the carrier is a resin obtained by heat-treating a copolymer.
[In Formula (1), R1 represents a hydrogen atom or a methyl group, R2 represents an alkyl group having 1 to 4 carbon atoms, and m represents an integer of 1 to 8. X represents 10 to 90 mol%. ]
[In Formula (2), R1 represents a hydrogen atom or a methyl group, R2 represents an alkyl group having 1 to 4 carbon atoms, R3 represents an alkyl group having 1 to 8 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms. Represents a group, and m represents an integer of 1 to 8. Y represents 10 to 90 mol%. ]   6. The electrostatic latent image developing carrier according to claim 1, wherein the carrier has a volume average particle diameter of 20 μm or more and 45 μm or less.   A two-component developer comprising the carrier according to any one of claims 1 to 6 and a color toner.   A developer for replenishment comprising 2 to 50 parts by weight of toner with respect to 1 part by weight of the carrier according to claim 1.   The developer according to claim 7 or 8, wherein an electrostatic latent image carrier, a charging member for charging a surface of the electrostatic latent image carrier, and an electrostatic latent image formed on the electrostatic latent image carrier. A process cartridge comprising: a developing unit that develops the toner using a toner; and a cleaning member that cleans the electrostatic latent image carrier.   An electrostatic latent image carrier, a charging unit for charging the latent image carrier, an exposure unit for forming an electrostatic latent image on the latent image carrier, and an electrostatic latent image carrier formed on the electrostatic latent image carrier. A developing unit that develops the electrostatic latent image using the developer according to claim 7 to form a toner image, and transfers the toner image formed on the electrostatic latent image carrier to a recording medium. An image forming apparatus comprising: a transfer unit that fixes the toner image transferred to the recording medium.