JP2012053421A - Carrier for two-component developer - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a carrier excellent in toner spent resistance, wear resistance (resistance against scraping or peeling) of a coating film, and to provide developer containing the carrier, a container with developer containing the developer, and an image forming method and a process cartridge using the developer.SOLUTION: A carrier for an electrostatic latent image developer comprises a core particle having magnetism and a resin layer coating the particle surface. The resin layer contains a resin prepared by heat treatment of a copolymer containing at least a trialkoxysilane acrylate or methacrylate and a dialkoxyalkylsilane acrylate or methacrylate. The resin layer contains a crosslinked product obtained by hydrolyzing the above copolymer to produce a silanol group and then condense it by using an organotitanium compound.

Description

  The present invention relates to a carrier in which a coating layer is formed on the surface of core material particles, a manufacturing method thereof, a developer, a container containing a developer, an image forming method, and a process cartridge.

  In electrophotographic image formation, an electrostatic latent image is formed on an electrostatic latent image carrier such as a photoconductive substance, and a charged toner is attached to the electrostatic latent image to form a toner image. After that, the toner image is transferred to a recording medium and fixed to form an output image. In recent years, the technology of copying machines and printers using an electrophotographic system is rapidly expanding from monochrome to full color, and the full color market tends to expand.

  In full-color image formation, generally, color toners of three colors of yellow, magenta, and cyan or four color toners obtained by adding black to this are laminated to reproduce all colors. Therefore, in order to obtain a clear full color image with excellent color reproducibility, it is necessary to smooth the surface of the fixed toner image to reduce light scattering. For these reasons, the image gloss of conventional full-color copying machines and the like is often 10 to 50% of medium to high gloss.

  In general, as a method for fixing a dry toner image on a recording medium, a contact heating fixing method in which a roller or belt having a smooth surface is heated and pressed against the toner is frequently used. Such a method has high thermal efficiency and enables high-speed fixing, and can give gloss and transparency to the color toner. On the other hand, the surface of the heat-fixing member is brought into contact with the molten toner under pressure. Then, in order to peel off, a so-called offset phenomenon occurs in which a part of the toner image adheres to the surface of the fixing roller and is transferred onto another image.

  In order to prevent such an offset phenomenon, the surface of the fixing roller is formed of silicone rubber or fluorine resin having excellent releasability, and further, an oil for preventing toner adhesion such as silicone oil is applied to the surface of the fixing roller. This method is generally adopted. However, such a method is extremely effective in preventing toner offset, but requires a device for supplying oil, and there is a problem that the fixing device is increased in size.

  For this reason, in monochrome image formation, an oilless system in which viscoelasticity at the time of melting is large and toner containing a release agent is used so that the melted toner does not break internally, so that no oil is applied to the fixing roller, or There is a tendency to adopt a system in which a small amount of oil is applied.

  On the other hand, in full-color image formation, as in the case of monochrome image formation, an oilless system tends to be employed for the purpose of downsizing the fixing device and simplifying the configuration. However, in full-color image formation, it is necessary to reduce the viscoelasticity of the toner at the time of melting in order to smooth the surface of the fixed toner image. Therefore, offset occurs more than in the case of monochrome image formation without gloss. This makes it difficult to adopt an oilless system. Further, when a toner containing a release agent is used, adhesion of the toner is increased and transferability to a recording medium is decreased. Furthermore, there is a problem in that the durability is lowered due to the occurrence of toner filming and a decrease in chargeability.

  On the other hand, as a 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 a photoreceptor, photosensitivity The length of the carrier can be increased by coating the surface of the carrier core with a resin having a low surface energy, such as a fluororesin or a silicone resin, for the purpose of protecting the body from scratches or abrasion, controlling the charge polarity, and adjusting the charge amount. Life expectancy has been increasing.

  Examples of a carrier coated with a low surface energy resin include a carrier coated with a room temperature curable silicone resin and a positively chargeable nitrogen resin disclosed in Japanese Patent Application Laid-Open No. 55-127469 of Patent Document 1, A carrier coated with a coating material containing at least one modified silicone resin disclosed in Japanese Patent Application Laid-Open No. 55-157571; a room temperature curable silicone resin disclosed in Japanese Patent Application Laid-Open No. 56-140358 of Patent Document 3; and a styrene / acrylic resin A carrier having a coated resin coating layer, a carrier in which the core particle surface disclosed in JP-A-57-96355 disclosed in JP-A-57-96355 is coated with two or more layers of silicone resin so that there is no adhesion between the layers, Patent Document 5 JP-A-57-96356 discloses a carrier in which a silicone resin is applied in multiple layers on the surface of a core particle, and JP-A-57-96356 discloses A carrier whose surface is coated with a silicon resin containing silicon carbide disclosed in Japanese Patent Laid-Open No. 8-207054, and a positive coated with a material having a critical surface tension of 20 dyn / cm or less disclosed in Japanese Patent Laid-Open No. 61-110161 of Patent Document 7. Examples include a chargeable carrier, a carrier coated with a coating material containing a fluorine alkyl acrylate disclosed in Japanese Patent Application Laid-Open No. 62-273576, and a developer comprising a toner containing a chromium-containing azo dye. .

  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 has been conventionally known that a coating layer formed by condensation is provided on the surface of carrier core particles. For example, JP 2001-92189A discloses a silicone resin containing an organic titanium catalyst as a core material. What is coated around the particle is disclosed. Examples of titanium-based catalysts include diisopropoxybis (acetylacetonate), tetraisopropoxytitanium, isopropoxy (2-ethylhexanediolato) titanium, bis ( (Acryloyloxy) isopropoxyisostearoyloxytitanium, bis (2,4-pentanedionato) (1, - are enumerated as propanedionato isocyanatomethyl) ones same and titanium effect. Japanese Patent Application Laid-Open No. 06-222621 of Patent Document 10 discloses organopolysiloxane, organosilane, titanium (for example, tetraisopropoxytitanium), tin (for example, dibutyltin diacetate), zinc, cobalt, iron, Disclosed is a coating obtained by coating the surface of core material particles with a coating agent mainly composed of a coating composition comprising a curing catalyst which is at least one selected from the group consisting of aluminum compounds and amines. Has been. Furthermore, in JP-A-2006-337828 of Patent Document 11, the surface of the core material particles includes a quaternary ammonium salt catalyst, an aluminum catalyst, or a titanium catalyst (specifically, the diisopropoxybis (acetylacetonate)). What is coated with a contained silicone resin or modified silicone resin is disclosed.

However, in recent years, there has been a tendency for the toner to have a smaller particle size in order to improve the image quality, and with the increase in printing speed, toner spent on the carrier is more likely to occur.
Furthermore, in the case of a developer in which maintenance is facilitated by adding wax to the toner, the amount of toner spent is very large, and the toner charge amount is reduced, and the margin for toner scattering and background contamination is reduced. Currently.

  In a full-color electrophotographic system, if the toner spent on the carrier or the coating film is scraped or peeled off, the carrier resistance or the developer pumping amount will change, the image density, especially the highlight density, will change, and the coating will be scraped. The color toner (especially yellow toner) is stained by the removal of the filler due to the above, and the high image quality cannot be maintained.

  Moreover, when forming a coating layer, there exists a problem that blocking generate | occur | produces or durability falls.

  The present invention has been made in view of the above-mentioned problems of the prior art, a carrier excellent in toner spent property and coating abrasion resistance (scraping / peeling), a developer having the carrier, a developer-containing container having the developer, and the carrier. It is an object to provide an image forming method and a process cartridge using a developer.

The said subject of this invention is solved by following (1)-(21).
(1) A carrier for an electrostatic latent image developer comprising magnetic core particles and a resin layer covering the surface, wherein the resin layer is at least a monomer component represented by the following general formula (1) A resin layer obtained by heat-treating a copolymer containing an A site derived from A and a B site derived from the monomer component B represented by the following general formula (2), the resin layer comprising: A carrier for an electrostatic latent image developer comprising a crosslinked product obtained by hydrolyzing the copolymer to form a silanol group and condensing using an organic titanium system.

（式中において、Ｒ^１、ｍ、Ｒ^２、Ｒ^３、Ｘ、及びＹは以下に該当するものを示す。）
Ｒ^１：水素原子、またはメチル基
ｍ：炭素原子数１〜８のアルキレン基
Ｒ^２：炭素原子数１〜４のアルキル基
Ｒ^３は、炭素数１〜８のアルキル基、または炭素数１〜４のアルコキシ基
Ｘ：１０〜９０モル％
Ｙ：１０〜９０モル％。
（２）前記共重合体は、下記一般式（５）で表される共重合体を含むことを特徴とする前記（１）項に記載の静電潜像現像剤用キャリア。

(In the formula, R ¹ , m, R ² , R ³ , X, and Y are as follows.)
R ¹ : hydrogen atom, or methyl group m: alkylene group having 1 to 8 carbon atoms R ² : alkyl group having 1 to 4 carbon atoms R ³ is an alkyl group having 1 to 8 carbon atoms, or 1 to 1 carbon atoms 4 alkoxy group X: 10 to 90 mol%
Y: 10 to 90 mol%.
(2) The carrier for an electrostatic latent image developer according to item (1), wherein the copolymer includes a copolymer represented by the following general formula (5).

（式中において、Ｒ^１、ｍ、Ｒ^２、Ｒ^３、Ｘ、Ｙ、及びＺは以下に該当するものを示す。
）
Ｒ^１：水素原子、またはメチル基
ｍ：炭素原子数１〜８のアルキレン基
Ｒ^２：炭素原子数１〜４のアルキル基
Ｒ^３：炭素数１〜８のアルキル基、または炭素数１〜４のアルコキシ基
Ｘ：１０〜４０モル％
Ｙ：１０〜４０モル％
Ｚ：３０〜８０モル％
６０モル％＜Ｙ＋Ｚ＜９０モル％。

(In the formula, R ¹ , m, R ² , R ³ , X, Y, and Z are as follows.)
)
R ¹ : hydrogen atom or methyl group m: an alkylene group having 1 to 8 carbon atoms R ² : an alkyl group having 1 to 4 carbon atoms R ³ : an alkyl group having 1 to 8 carbon atoms, or 1 to 4 carbon atoms Alkoxy group X: 10 to 40 mol%
Y: 10 to 40 mol%
Z: 30 to 80 mol%
60 mol% <Y + Z <90 mol%.

(3) The carrier for an electrostatic latent image developer according to (1) or (2), wherein the organic titanium-based catalyst is titanium alkoxide.
(4) The carrier for an electrostatic latent image developer according to the item (1) or (2), wherein the organotitanium catalyst is a titanium chelate.
(5) The carrier for an electrostatic latent image developer according to any one of (1) to (4), wherein the carrier is obtained by coating the coating layer and then performing heat treatment.
(6) The carrier for an electrostatic latent image developer according to any one of (1) to (5), wherein a heat treatment temperature during the heat treatment is 100 to 350 ° C.
(7) The carrier for an electrostatic latent image developer according to any one of (1) to (6), wherein the coating layer further contains conductive particles.
(8) The electrostatic latent image developer carrier according to any one of (1) to (7), wherein the conductive particles are conductive fine particles containing at least barium sulfate.
(9) The ratio of the content of Ba and Si with respect to all elements measured by X-ray photoelectron spectroscopy (XPS), Ba / Si is 0.01 or more and 0.08 or less. The carrier for an electrostatic latent image developer according to any one of items 1) to (8).
(10) The carrier for an electrostatic latent image developer as described in (7) above, wherein the conductive particles are tin oxide fine particles having carbon on the surface.
(11) The electrostatic latent image as described in any one of (1) to (10) above, wherein the volume resistivity is 1 × 10 ⁹ Ω · cm or more and 1 × 10 ¹⁷ Ω · cm or less. Developer carrier.
(12) The carrier for an electrostatic latent image developer according to any one of (1) to (11), wherein the coating layer has an average film thickness of 0.05 μm to 4 μm.
(13) The carrier for an electrostatic latent image developer according to any one of (1) to (12), wherein the core material particles have a weight average particle diameter of 20 μm to 65 μm.
(14) The electrostatic latent image developer carrier according to any one of (1) to (13) above, wherein the magnetization in a magnetic field of 1 kOe is 40 Am ² / kg or more and 90 Am ² / kg or less. .
(15) A developer comprising the carrier and the toner according to any one of (1) to (14).
(16) The developer according to item (15), wherein the toner is a color toner.
(17) A replenishment developer containing 2 to 50 parts by weight of toner with respect to 1 part by mass of the carrier, wherein the carrier is any one of items (1) to (14). A developer for replenishment characterized by being a carrier.
(18) A method for producing a carrier having a step of forming a coating layer on the surface of the core particle, wherein the coating step includes the A site derived from the monomer component A represented by the following general formula (1) and the following general formula It contains a cross-linked product obtained by hydrolyzing a copolymer containing the B moiety derived from the monomer component B represented by the formula (2), generating a silanol group, and condensing using an organic titanium catalyst. A method for producing a carrier, which is a step of forming the coating layer.

（式中において、Ｒ^１、ｍ、Ｒ^２、Ｒ^３、Ｘ、及びＹは以下に該当するものを示す。）
Ｒ^１：水素原子、またはメチル基
ｍ：炭素原子数１〜８のアルキレン基
Ｒ^２：炭素原子数１〜４のアルキル基
Ｒ^３は、炭素数１〜８のアルキル基、または炭素数１〜４のアルコキシ基
Ｘ：１０〜９０モル％
Ｙ：１０〜９０モル％。

(In the formula, R ¹ , m, R ² , R ³ , X, and Y are as follows.)
R ¹ : hydrogen atom, or methyl group m: alkylene group having 1 to 8 carbon atoms R ² : alkyl group having 1 to 4 carbon atoms R ³ is an alkyl group having 1 to 8 carbon atoms, or 1 to 1 carbon atoms 4 alkoxy group X: 10 to 90 mol%
Y: 10 to 90 mol%.

(19) A developer-containing container comprising the developer according to any one of (15) to (17).
(20) 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 may be any of the above items (15) to (17). Development using the developer described above to form a toner image, transferring the toner image formed on the electrostatic latent image carrier to a recording medium, and transferring the toner image to the recording medium And a step of fixing the toner image.
(21) An electrostatic latent image carrier and an electrostatic latent image formed on the electrostatic latent image carrier are developed using the developer according to any one of (15) to (17). The process cartridge is characterized in that the means for supporting is at least integrally supported.

  According to the present invention, a carrier excellent in toner spent property and coating abrasion resistance (scraping / peeling), a developer having the carrier, a developer-containing container having the developer, an image forming method using the developer, and A process cartridge can be provided.

It is a figure which shows the cell used when measuring the volume specific resistance of the carrier of this invention. It is a figure which shows an example of the process cartridge of this invention.

Next, the form for implementing this invention is demonstrated in detail with drawing.
The electrostatic latent image developer carrier of the present invention comprises magnetic core material particles and a resin layer covering the surface thereof, and comprises magnetic core material particles and a coating layer covering the surface of the core material particles. The electrostatic latent image developer carrier, wherein the coating layer hydrolyzes the copolymer represented by the following general formulas (3) and (5) to generate silanol groups, It is a carrier for an electrostatic latent image developer, containing a cross-linked product obtained by condensation.
That is, the carrier of the present invention is a binary system obtained by radical copolymerization of a monomer A component and a monomer B component described below (however, in order to facilitate understanding of the quantitative ratio and the like, indicated by a site derived from each component). An acrylic copolymer (copolymer of the following general formula (3)) or a ternary system obtained by radical copolymerization of the monomer A component, the monomer B component and the monomer C component (the following general formula (4)). The acrylic copolymer (copolymer of general formula (5)) is hydrolyzed to form a silanol group, which is crosslinked and coated by condensation using an organic titanium catalyst, and then heat-treated. The resulting electrostatic latent image developing carrier.

(In the formula, R ¹ , m, R ² , R ³ , X, Y, and Z are as follows.)
R ¹ : a hydrogen atom or a methyl group.
m: alkylene group such as methylene group having 1 to 8 carbon atoms, ethylene group, propylene group, butylene group.
R ² : an alkyl group such as a methyl group having 1 to 4 carbon atoms, an ethyl group, a propyl group, an isopropyl group, and a butyl group.
R ³ : Alkyl group such as methyl group having 1 to 8 carbon atoms, ethyl group, propyl group, isopropyl group and butyl group, or alkoxy group having 1 to 4 carbon atoms such as methoxy group, ethoxy group, propoxy group and butoxy group. Group.

[Monomer A component]

前Ａ成分（Ａ部位）の式中、
Ｒ^１：水素原子、またはメチル基、
ｍ：炭素原子数１〜８のメチレン基、エチレン基、プロピレン基、ブチレン基等のアルキレン基、
Ｒ^２：炭素原子数１〜４の脂肪族炭化水素基であり、メチル基、エチル基、プロピル基、及びブチル基、である。
また、Ａ成分において、Ｘ＝１０〜９０モル％であり、より好ましくは、３０〜７０モル％である。

In the formula of the former A component (A site),
R ¹ : a hydrogen atom or a methyl group,
m: alkylene group such as methylene group having 1 to 8 carbon atoms, ethylene group, propylene group, butylene group,
R ^{2 is} an aliphatic hydrocarbon group having 1 to 4 carbon atoms, and is a methyl group, an ethyl group, a propyl group, or a butyl group.
Moreover, in A component, it is X = 10-90 mol%, More preferably, it is 30-70 mol%.

The A component has an atomic group having a large number of methyl groups in the side chain and tris (trimethylsiloxy) silane. When the ratio of the A component to the entire resin increases, the surface energy decreases, and the resin component of the toner. , Adhesion of wax components and the like is reduced. When the A component is less than 10 mol%, a sufficient effect cannot be obtained, and the adhesion of the toner component increases rapidly. Moreover, when it exceeds 90 mol%, the B component (B site) and the C component (C site) are reduced, the crosslinking does not proceed, the toughness is insufficient, and the adhesion between the core material and the resin layer is reduced. The durability of the carrier coating is deteriorated.
R ² is an alkyl group having 1 to 4 carbon atoms, and examples of such a monomer component include a tris (trialkylsiloxy) silane compound represented by the following formula.
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
_{CH 2 = CH-COO-C} 3 H 6 -Si (OSiMe 3) 3
_{CH 2 = CMe-COO-C} 4 H 8 -Si (OSiMe 3) 3
_{CH 2 = CMe-COO-C} 3 H 6 -Si (OSiEt 3) 3
_{CH 2 = CH-COO-C} 3 H 6 -Si (OSiEt 3) 3
_{CH 2 = CMe-COO-C} 4 H 8 -Si (OSiEt 3) 3
_{CH 2 = CMe-COO-C} 3 H 6 -Si (OSiPr 3) 3
_{CH 2 = CH-COO-C} 3 H 6 -Si (OSiPr 3) 3
_{CH 2 = CMe-COO-C} 4 H 8 -Si (OSiPr 3) 3

  The production method of the monomer A component is not particularly limited, but is described in a method of reacting tris (trialkylsiloxy) silane with allyl acrylate or allyl methacrylate in the presence of a platinum catalyst, or described in JP-A No. 11-217389. It can be obtained by a method of reacting methacryloxyalkyltrialkoxysilane and hexaalkyldisiloxane in the presence of a carboxylic acid and an acid catalyst.

[Monomer B component]

In the formula of the previous B component (B site),
R ¹ : a hydrogen atom or a methyl group,
m: alkylene group such as methylene group having 1 to 8 carbon atoms, ethylene group, propylene group, butylene group,
R ^2: an aliphatic hydrocarbon group having 1 to 4 carbon atoms, a methyl group, an ethyl group, a propyl group, and butyl group,
R ³ : an alkyl group having 1 to 8 carbon atoms (methyl group, ethyl group, propyl group, butyl group, etc.) or an alkoxy group having 1 to 4 carbon atoms (methoxy group, ethoxy group, propoxy group, butoxy group), Show.

That is, the B component is a radically polymerizable bifunctional or trifunctional silane compound, and Y = 10 to 90 mol%, more preferably 30 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. It is also conceivable that a large number of hydrolyzed crosslinking components remain as silanol groups, deteriorating environmental characteristics (humidity dependency).

  Examples of such component B include 3-methacryloxypropyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltriethoxysilane, and 3-methacryloxypropylmethyl. Examples include dimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltri (isopropoxy) silane, and 3-acryloxypropyltri (isopropoxy) silane.

In the case of the ternary acrylic copolymer, in addition to the A component and the B component, the following C component is further copolymerized to be a copolymer represented by the following general formula (3). This hydrolyzes.
As C component, acrylic acid ester and methacrylic acid ester are preferable, and specifically, methyl methacrylate, methyl acrylate, ethyl methacrylate, ethyl acrylate, butyl methacrylate, butyl acrylate, 2- (dimethylamino) ethyl methacrylate, 2- ( Examples include dimethylamino) ethyl acrylate, 3- (dimethylamino) propyl methacrylate, 3- (dimethylamino) propyl acrylate, 2- (diethylamino) ethyl methacrylate, and 2- (diethylamino) ethyl acrylate.
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.

[Monomer C component]

（上式中、Ｒ^１、Ｒ^２は、Ａ成分、Ｂ成分と同様な意味を有する。）

(In the above formula, R ¹ and R ² have the same meanings as the A component and the B component.)

[Ternary acrylic copolymer]

In the case of this ternary acrylic copolymer, the ratio (X, Y, Z) of each component is the same as that of the binary acrylic copolymer as the C component (C site) is added. As a matter of course, the ratio (X, Y, Z) of each component is Z = 30 to 80 mol%. More preferably, it is 35 to 75 mol%, and 60 mol% <Y + Z <90 mol%, and more preferably 70 mol% <Y + Z <85 mol%. That is, X is 10-40 mol%.
The C component imparts flexibility to the coating and improves the adhesion between the core material and the coating.
If the C component is less than 30 mol%, sufficient adhesion cannot be obtained, and if it exceeds 80 mol%, either X or Y becomes 10 or less, so that the water repellency, hardness and flexibility of the carrier film are reduced. It becomes difficult to achieve both (film shaving).

Japanese Patent No. 3691115 discloses a technique for improving durability by crosslinking a coating.
That is, in the one described in Japanese Patent No. 3691115, at least one selected from the group consisting of an organopolysiloxane having a vinyl group at the terminal, a hydroxyl group, an amino group, an amide group, and an imide group on the surface of the magnetic particle. A carrier for developing an electrostatic charge image, characterized by coating a copolymer with a radical copolymerizable monomer having two functional groups with a thermosetting resin crosslinked with an isocyanate compound.・ Currently, sufficient durability is not obtained in cutting.
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. The functional group (active hydrogen-containing group) per unit weight that reacts (crosslinks) with the compound is small, and a two-dimensional or three-dimensional dense crosslinked structure cannot be formed at the crosslinking point. Therefore, if it is used for a long time, the film is easily peeled off or scraped off (the abrasion resistance of the film is small), and it is assumed that 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, which causes a decrease in image density, contamination when toner is increased, and toner scattering.

In the present invention, it is a copolymer resin having a large number of bifunctional or trifunctional crosslinkable functional groups (points) per unit weight of the resin (2 to 3 times greater per unit weight), Since this is further cross-linked by condensation polymerization, it is considered that the coating is extremely tough and difficult to scrape, and high durability is achieved.
Further, it is presumed that the aging stability of the coating is maintained 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.

  Examples of the condensation polymerization catalyst for the crosslinkable monomer B component include titanium-based catalysts, tin-based catalysts, zirconium-based catalysts, and aluminum-based catalysts. In the present invention, among these various catalysts, titanium that gives excellent results is obtained. Among the system catalysts, titanium alkoxide and titanium chelate are based on the knowledge that the most preferable results are obtained as a catalyst. This is considered to be because the effect of promoting the condensation reaction of the silanol group is large and the catalyst is hardly deactivated. An example of a titanium alkoxide catalyst is titanium diisopropoxybis (ethyl acetoacetate) (chemical formula is structural formula 2), and an example of a titanium chelate catalyst is titanium diisopropoxy bis (triethanolaminate). (Chemical formula is structural formula 3).

  The coating layer has a silanol group and / or a hydrolyzable functional group, a silicone resin, a titanium diisopropoxybis (ethylacetoacetate) catalyst, and, if necessary, a silanol group and / or a hydrolyzable functional group. It can form using the composition for coating layers containing resin other than a silicone resin, 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 coating layer composition, It may be formed by condensation. The method of condensing silanol groups while coating the core material particles with the coating layer composition is not particularly limited, but the method of coating the core particles with the coating layer composition while applying heat, light, etc. Etc. Further, the method for condensing the silanol group after coating the core material particles with the coating layer composition is not particularly limited, and examples thereof include a method of heating after coating the core material particles with the coating layer composition. It is done.

  The resin other than the silicone resin having a silanol group and / or a hydrolyzable functional group is not particularly limited, but acrylic resin, amino resin, polyvinyl resin, polystyrene resin, halogenated olefin resin, polyester, polycarbonate, polyethylene, Fluorine such as polyvinyl fluoride, polyvinylidene fluoride, polytrifluoroethylene, polyhexafluoropropylene, copolymers of vinylidene fluoride and vinyl fluoride, terpolymers of tetrafluoroethylene, vinylidene fluoride and non-fluorinated monomers Examples thereof include a terpolymer, a silicone resin having no silanol group or a hydrolyzable functional group, and two or more types may be used in combination. Among them, an acrylic resin is preferable because it has high adhesion to the core particles and conductive 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, when the strong impact is applied to the coating layer due to the friction between the toner and the carrier or between the carriers, the impact is applied. It can be absorbed and maintained without damaging the coating layer.

The coating layer further preferably contains a cross-linked product of an acrylic resin and an amino resin.
Thereby, fusion | melting of coating 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. In addition, 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 the 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 particle can further be improved, and the dispersion stability of electroconductive particle 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.

In the present invention, the coating layer composition preferably contains conductive particles. Thereby, the volume specific resistance of the carrier can be adjusted. Although it does not specifically limit as electroconductive particle, Metal oxides, such as carbon black, ITO, a tin oxide, zinc oxide, barium sulfate, metal salts, etc. are mentioned, You may use 2 or more types together.
It is preferable that the addition amount of electroconductive particle is 0.1-1000 mass% with respect to a silicone resin. When the addition amount of the conductive particles is less than 0.1% by mass, the effect of adjusting the volume specific resistance of the carrier may be insufficient, and when it exceeds 1000% by mass, the conductive fine particles may be retained. It becomes difficult and the surface layer of the carrier is easily destroyed.

  The electrostatic latent image developing carrier particularly preferably contains barium sulfate in the coating layer. By including the barium sulfate in the coating layer, the chargeability with the toner is high, and it becomes difficult for the external additive and the toner resin to be spent on the surface layer. This is presumably because barium sulfate has higher hardness than the resin of the coating layer, so that the adhering additive and resin are easily detached by friction with other carriers. For this reason, the electrostatic latent image developing carrier can maintain the chargeability even after output over a long image area.

Furthermore, another effect can be expected by containing the barium sulfate.
When operating for a long time with a low image area (low toner balance), the carrier coating layer is scraped and the core material is exposed, the resistance of the carrier decreases, the carrier is developed, and white spots appear on the image. There is a problem of generating abnormal images.
However, the presence of the barium sulfate particles dispersed in the resin increases the strength of the coating layer and provides a carrier coat film that is difficult to scrape. Accordingly, even if the developing device is operated for a long time in a state where the toner balance is small, the amount of abrasion of the coating layer is small, and the carrier can be used for a much longer period than the coating layer coated only with resin.

Here, it is preferable that Ba / Si, which is a ratio of the content of Ba and Si to all elements measured by X-ray photoelectron spectroscopy (XPS), is 0.01 or more and 0.08 or less.
If the Ba / Si is less than 0.01, the charging ability by Ba is not sufficient, so that the charge cannot be maintained, and problems such as scumming and toner scattering occur. Further, since the amount of the barium sulfate is small, the coating layer is easily scraped, and the problem of carrier adhesion is likely to occur.
On the other hand, if the Ba / Si exceeds 0.08, the charge amount is too high, so that sufficient developing ability cannot be obtained. Further, since the amount of the barium sulfate with respect to the resin is too large, the dispersed particle size is deteriorated, and the barium sulfate is present in the coating layer in an aggregated state, so that the barium sulfate is easily detached, and background contamination and toner scattering are caused. Cause problems.
In addition, as said Ba / Si ratio, 0.03 or more is preferable. This is because when the use in a higher image area ratio such as a printing industry is expected, a sufficient charge amount may not be obtained if it is less than 0.03.

Moreover, there is no restriction | limiting in particular as content of Ba with respect to all the elements measured by the said X ray photoelectron spectroscopy (XPS), Although it can select suitably according to the objective, 0.2 atomic% (number) -1. It is preferably 2 atomic% (number).
If the content of Ba is less than 0.2 atomic% (number), the charging ability by the Ba is not sufficient, so that charging cannot be maintained, and problems such as scumming and toner scattering may occur. On the other hand, if it exceeds 1.2 atomic% (number), the charge amount is too high, and sufficient developing ability may not be obtained.
The method for adjusting the Ba / Si ratio is not particularly limited, but it is effective to adjust the content of the barium sulfate.

As content of the said barium sulfate, 2 mass parts-12 mass parts are preferable with respect to 100 mass parts of said silicone resins, 4 mass parts-10 mass parts are more preferable, and 6 mass parts-10 mass parts are especially preferable. .
If the content is less than 2 parts by mass, the amount of barium present on the surface is reduced, and sufficient charging ability cannot be obtained, so that problems such as background contamination and toner scattering may occur. When it exceeds the mass part, the amount of barium sulfate in the resin is saturated, and the coating film may be fragile.

  In addition, when dispersing the barium sulfate in the carrier coating solution (coating layer composition), it is important to make the process more dispersible. This is because the surface area of the carrier coat surface naturally increases because the surface area of the barium sulfate increases when finely dispersed even if the amount is the same. In addition, since the strength of the coating layer is increased, the carrier resistance does not decrease even when a stronger stress is applied.

Here, the Ba / Si content ratio, Ba / Si, is measured using an X-ray electron spectrometer (XPS). Details are described below.
Measuring device: AXIS-ULTRA manufactured by Kratos
Measurement light source: Al (monochromator)
Measurement output: 90 W (15 kV, 6 mA)
Measurement area: 900 × 600 μm ²
Pass energy: (wide scan) 160eV, (narrow scan) 40eV
Energy step: (Wide scan) 1.0 eV, (narrow scan) 0.2 eV
Relative sensitivity coefficient: Uses Kratos' relative sensitivity coefficient Because it is a magnetic substance, measurement is performed with MAGNET CONTROLLER turned off.
In the measurement, a sample is put in a cylindrical hole-dipped chip having a depth of 0.3 mm, and a flat portion of the surface is measured. The measurement result is expressed in atomic% (number), and the ratio of the measurement values is used.

Furthermore, the ratio of the average particle diameter D of the barium sulfate contained in the coating layer to the thickness h of the coating layer is preferably 1.0 <D / h <2.0.
When the D / h is less than 1.0, the barium sulfate fine particles are buried in the binder resin, so that the convex barium sulfate is reduced on the carrier surface and the toner toner is sufficiently suppressed. May not be able to get. In addition, since the number of convex particles is small, the binder resin layer is likely to be scraped, and there may be a problem that the resistance decrease is large when the carrier is stirred for a long time.
When the D / h exceeds 2.0, the contact area between the barium sulfate and the binder resin is small, so that sufficient restraining force cannot be obtained, and the barium sulfate may be easily detached. When the barium sulfate is detached, the resistance may be lowered.

The method for measuring the thickness h of the resin part in the coating layer is not particularly limited. For example, the thickness of the resin part of the coating layer covering the carrier surface is observed using a transmission electron microscope (TEM). Can be obtained from the average value. Specifically, only the thickness of the resin part existing between the core material surface and the particles is measured. The thickness of the resin part existing between the particles and the thickness of the resin part on the inorganic fine particles are not included in the measurement. The average of arbitrary 50 point measurements of the carrier cross section can be obtained and used as the thickness h (μm).
There is no restriction | limiting in particular as a measuring method of the average particle diameter (D) of the said barium sulfate, For example, a volume average particle diameter is measured with the automatic particle size distribution measuring apparatus CAPA-700 (made 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 the 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 1,000 ml beaker and diluted. The diluting solution is continuously stirred with a homogenizer. This diluted solution is measured with an ultracentrifugal automatic particle size distribution analyzer CAPA-700.
Measurement conditions Rotational speed: 2,000rpm
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: The density of barium sulfate is the true specific gravity value measured using a dry automatic bulk density meter Accupic 1330 (manufactured by Shimadzu Corporation).

Moreover, as another electroconductive fine particle used for this invention, a tin oxide, for example, the tin oxide fine particle which has carbon on the surface as mentioned above can be used.
When carbon adheres to the surface of the tin oxide fine particles, the resistance over time of the resistance value of tin oxide is brought about. The relationship between the amount of surface carbon and the resistance to conductive tin oxide is not clear, but if the amount of carbon on the surface is too large, the stability of the resistance value of the conductive tin oxide is poor. Further, when the toner is mixed into the toner due to carrier film scraping or the like, there is a problem of color stains as in the case of carbon black, so the surface carbon amount needs to be extremely small. The amount of carbon in the conductive fine particles can be quantitatively analyzed using a high-frequency combustion-infrared absorption method (manufactured by LECO, IR-412 type).

  Tin oxide fine particles (conductive fine particles) having carbon on the surface can be obtained, for example, by immersing tin oxide fine powder in ethanol and then holding it under a nitrogen atmosphere to perform surface modification treatment.

In the present invention, the coating layer composition preferably contains a silane coupling agent. Thereby, electroconductive particle can be disperse | distributed stably.
The silane coupling agent is not particularly limited, but r- (2-aminoethyl) aminopropyltrimethoxysilane, r- (2-aminoethyl) aminopropylmethyldimethoxysilane, r-methacryloxypropyltrimethoxysilane, N -Β- (N-vinylbenzylaminoethyl) -r-aminopropyltrimethoxysilane hydrochloride, r-glycidoxypropyltrimethoxysilane, r-mercaptopropyltrimethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, Vinyltriacetoxysilane, r-chloropropyltrimethoxysilane, hexamethyldisilazane, r-anilinopropyltrimethoxysilane, vinyltrimethoxysilane, octadecyldimethyl [3- (trimethoxysilyl) propyl] ammonium Chloride, r-chloropropylmethyldimethoxysilane, methyltrichlorosilane, dimethyldichlorosilane, trimethylchlorosilane, allyltriethoxysilane, 3-aminopropylmethyldiethoxysilane, 3-aminopropyltrimethoxysilane, dimethyldiethoxysilane, 1, Examples include 3-divinyltetramethyldisilazane and methacryloxyethyldimethyl (3-trimethoxysilylpropyl) ammonium chloride, and two or more of them may be used in combination.

Commercially available silane coupling agents include AY43-059, SR6020, SZ6023, SH6026, SZ6032, SZ6050, AY43-310M, SZ6030, SH6040, AY43-026, AY43-031, sh6062, Z-6911, sz6300, sz6075, sz6079, sz6083, sz6070, sz6072, Z-6721, AY43-004, Z-6187, AY43-021, AY43-043, AY43-040, AY43-047, Z-6265, AY43-204M, AY43-048, Z- 6403, AY43-206M, AY43-206E, Z6341, AY43-210MC, AY43-083, AY43-101, AY43-013, AY43-158E, Z-6920 Z-6940 (Toray Silicone Co., Ltd.).
It is preferable that the addition amount of a silane coupling agent is 0.1-10 mass% with respect to a silicone resin. When the addition amount of the silane coupling agent is less than 0.1% by mass, the adhesion between the core material particles and the conductive particles and the silicone resin is lowered, and the coating layer may fall off during long-term use. If it exceeds 10 mass%, toner filming may occur during long-term use.

  In the present invention, the coating layer preferably has an average film thickness of 0.05 to 4 μm. When the average film thickness is less than 0.05 μm, the coating layer is likely to be broken, and the film may be scraped off.

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.
In the present invention, the core particles preferably have a weight average particle diameter of 20 to 65 μm.
When the weight average particle diameter is less than 20 μm, carrier adhesion may occur. When the weight average particle diameter exceeds 65 μm, the reproducibility of image details may be reduced and a fine image may not be formed.
The weight average particle diameter can be measured using a Microtrac particle size distribution model HRA9320-X100 (manufactured by Nikkiso Co., Ltd.).

The carrier of the present invention preferably has a magnetization of 40 to 90 Am ² / kg in a magnetic field of 1 kOe (10 ⁶ / 4π [A / m]). When this magnetization is less than 40 Am ² / kg, the carrier may adhere to the image, and when it exceeds 90 Am ² / kg, the magnetic ear becomes hard and image blurring may occur.
Magnetization can be measured using VSM-P7-15 (manufactured by Toei Kogyo Co., Ltd.).

The carrier of the present invention preferably has a volume resistivity of 1 × 10 ⁹ to 1 × 10 ¹⁷ Ω · cm. If the volume resistivity is less than 1 × 10 ⁹ Ω · cm, carrier adhesion may occur in the non-image area, and if it exceeds 1 × 10 ¹⁷ Ω · cm, the edge effect may be at an unacceptable level. is there.
The volume resistivity can be measured using the cell shown in FIG. Specifically, first, a carrier (3) is placed in a cell composed of a fluororesin container (2) in which an electrode (1a) and an electrode (1b) having a surface area of 2.5 cm × 4 cm are accommodated at a distance of 0.2 cm. ) And is tapped 10 times with a drop height of 1 cm and a tapping speed of 30 times / minute. Next, a DC voltage of 1000 V is applied between the electrodes (1a) and (1b), and a resistance value r [Ω] after 30 seconds is measured using a high resistance meter 4329A (manufactured by Yokogawa Hewlett-Packard Company). From the following formula 1, the volume resistivity [Ω · cm] can be calculated.

The developer of the present invention has the carrier and toner of the present invention.
The toner contains a binder resin and a colorant, and may be a monochrome toner or a color toner. Further, the toner may contain a release agent for application 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, the developer of the present invention maintains good quality for a long time. Can do.
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.

At this time, the apparatus for kneading the toner material is not particularly limited, but a batch type two roll; Banbury mixer; KTK type twin screw extruder (manufactured by Kobe Steel), TEM type twin screw extruder (Toshiba Machine) A continuous twin screw extruder such as a twin screw extruder (manufactured by KCK), a PCM type twin screw extruder (manufactured by Ikegai Iron Works), a KEX type twin screw extruder (manufactured by Kurimoto Iron Works); Examples thereof include a continuous single-shaft kneader such as Ko Nida (manufactured by Buss).
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 is not particularly limited, but is a homopolymer of styrene such as polystyrene, poly-p-styrene, polyvinyltoluene and the like; and a styrene-p-chlorostyrene copolymer, styrene-propylene copolymer, styrene. -Vinyltoluene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-methacrylic acid copolymer, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate 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-isoprene copolymer Styrene copolymers such as styrene-maleic acid ester copolymer; polymethyl methacrylate, polybutyl methacrylate, polyvinyl chloride, polyvinyl acetate, polyethylene, polyester, polyurethane, epoxy resin, polyvinyl butyral, polyacrylic acid Rosin, modified rosin, terpene resin, phenol resin, aliphatic or aromatic hydrocarbon resin, aromatic petroleum resin and the like, and two or more of them may be used in combination.

  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.

  Although it does not specifically limit as a coloring agent (pigment or dye), Cadmium yellow, mineral fast yellow, nickel titanium yellow, Navels yellow, naphthol yellow S, Hansa yellow G, Hansa yellow 10G, benzidine yellow GR, quinoline yellow lake, Yellow pigments such as 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; bengara, cadmium Red, Permanent Red 4R, Resol Red, Pyrazolone Red, Watching Red Calcium Salt, Lake Red D, Brilliant Carmine Red pigments such as B, eosin lake, rhodamine lake B, alizarin lake, brilliant carmine 3B; purple pigments such as fast violet B, methyl violet lake; cobalt blue, alkali blue, Victoria blue lake, phthalocyanine blue, metal-free phthalocyanine blue, Blue pigments such as phthalocyanine blue partially chlorinated, First Sky Blue, Indanthrene Blue BC; Green pigments such as Chrome Green, Chrome Oxide, Pigment Green B, Malachite Green Lake; Carbon Black, Oil Furnace Black, Channel Black, Lamp Black Azine dyes such as acetylene black and aniline black, black pigments such as metal salt azo dyes, metal oxides and composite metal oxides, etc. It may be.

  The release agent is not particularly limited, but includes 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 and the like. Two or more kinds may be used in combination.

  The toner may further contain a charge control agent. 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 is not particularly limited, but inorganic particles such as silica, titanium oxide, alumina, silicon carbide, silicon nitride, boron nitride, etc .; poly having an average particle size of 0.05 to 1 μm obtained by a soap-free emulsion polymerization method Examples thereof include resin particles such as methyl 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.

[Image forming apparatus and image forming method]
The image forming method of the present invention uses the developer of the present invention to form an electrostatic latent image on the electrostatic latent image carrier and the electrostatic latent image formed on the electrostatic latent image carrier. Development to form a toner image, a step of transferring the toner image formed on the electrostatic latent image carrier to a recording medium, and a step of fixing the toner image transferred to the recording medium.

  FIG. 2 shows an example of the process cartridge of the present invention. The process cartridge (10) comprises a photoreceptor (11), a charging device (12) for charging the photoreceptor (11), and an electrostatic latent image formed on the photoreceptor (11) using the developer of the present invention. A developing device 13 for developing and forming a toner image and a cleaning device (14) for removing the toner remaining on the photoconductor (11) after transferring the toner image formed on the photoconductor (11) to a recording medium. Are integrally supported, and the process cartridge (10) is detachable from a main body of an image forming apparatus such as a copying machine or a printer.

  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.

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.

  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.

[Resin synthesis example]
[Resin Synthesis Example 1] (Binary Copolymer Synthesis Example 1)
500 g of toluene was put into a flask equipped with a stirrer, a condenser, a thermometer, a nitrogen introducing tube, and a dropping device, and the temperature was raised to 90 ° C. under a nitrogen gas stream. Next, 2-methacryloxypropyltris (trimethylsiloxy) silane Silaplane TM-0701T (manufactured by Chisso Corporation) 211 g (500 mmol), 3-methacryloxypropyltrimethoxysilane 124.0 g (500 mmol) and 2,2′- A mixture of 0.58 g (3 mmol) of azobis (2-methylbutyronitrile) was added dropwise over 1 hour. Further, a solution prepared by dissolving 0.06 g (0.3 mmol) of 2,2′-azobis (2-methylbutyronitrile) in 15 g of toluene was added, and then mixed at 90 to 100 ° C. for 3 hours to obtain a resin 1. It was. Resin 1 had a weight average molecular weight of 35,000. Further, the resin 1 solution diluted with toluene so that the nonvolatile content was 25% by mass had a viscosity of 8.5 mm ² / sec and a specific gravity of 0.91.

[Resin Synthesis Example 2] (Binary Copolymer Synthesis Example 2)
Resin 2 was obtained in the same manner as Resin 1 except that 130 g (500 mmol) of 3-methacryloxypropylmethyldiethoxysilane was used instead of 124.0 g (500 mmol) of 3-methacryloxypropyltrimethoxysilane. Resin 2 had a weight average molecular weight of 33,000. Further, the resin 2 solution diluted with toluene so that the nonvolatile content was 25% by mass had a viscosity of 8.6 mm ² / sec and a specific gravity of 0.92.

[Resin Synthesis Example 3] (Binary Copolymer Synthesis Example 3)
3-methacryloxypropyltris (trimethylsiloxy) silane Silaplane TM-0701T (manufactured by Chisso Corporation) and 3-methacryloxypropyltrimethoxysilane were added in amounts of 379.8 g (900 mmol) and 24.8 g (100 mmol), respectively. Resin 3 was obtained in the same manner as Resin 1 except that Resin 3 had a weight average molecular weight of 34,000. In addition, the resin 3 solution diluted with toluene so that the nonvolatile content was 25% by mass had a viscosity of 8.7 mm ² / sec and a specific gravity of 0.90.

[Resin Synthesis Example 4] (Binary Copolymer Synthesis Example 4)
3-methacryloxypropyltris (trimethylsiloxy) silane Silaplane TM-0701T (manufactured by Chisso Corporation) and 3-methacryloxypropyltrimethoxysilane were added in amounts of 42.2 g (100 mmol) and 223.2 g (900 mmol), respectively. Resin 4 was obtained in the same manner as Resin 1 except that Resin 4 had a weight average molecular weight of 37,000. In addition, the resin 4 solution diluted with toluene so that the nonvolatile content was 25% by mass had a viscosity of 8.4 mm ² / sec and a specific gravity of 0.92.

[Resin Synthesis Example 5] (Binary Copolymer Synthesis Example 5)
Instead of 211 g (500 mmol) of 3-methacryloxypropyltris (trimethylsiloxy) silane Silaplane TM-0701T (manufactured by Chisso) and 124.0 g (500 mmol) of 3-methacryloxypropyltrimethoxysilane, 4-acryloxybutyl Resin 5 was obtained in the same manner as Resin 1 except that 168.5 g (250 mmol) of tris (triisopropylsiloxy) silane and 83 g (250 mmol) of 3-methacryloxypropyltriisopropoxysilane were used. Resin 5 had a weight average molecular weight of 39000. Further, the resin 5 solution diluted with toluene so that the nonvolatile content was 25% by mass had a viscosity of 8.9 mm ² / sec and a specific gravity of 0.94.

[Resin Synthesis Example 6] (Ternary Copolymer Synthesis Example 1)
300 g of toluene was put into a flask equipped with a stirrer, a condenser, a thermometer, a nitrogen introducing tube, and a dropping device, and the temperature was raised to 90 ° C. under a nitrogen gas stream. Next, 84.4 g (200 mmol) of 3-methacryloxypropyltris (trimethylsiloxy) silane Silaplane TM-0701T (manufactured by Chisso Corporation), 37.2 g (150 mmol) of 3-methacryloxypropyltrimethoxysilane, methyl methacrylate A mixture of 65.0 g (650 mmol) and 2,2′-azobis (2-methylbutyronitrile) 0.58 g (3 mmol) was added dropwise over 1 hour. Further, a solution prepared by dissolving 0.06 g (0.3 mmol) of 2,2′-azobis (2-methylbutyronitrile) in 15 g of toluene was added, and then mixed at 90 to 100 ° C. for 3 hours to obtain a resin 6. It was. Resin 6 had a weight average molecular weight of 34,000. Moreover, the resin 6 solution diluted with toluene so that the nonvolatile content was 25% by mass had a viscosity of 8.7 mm ² / sec and a specific gravity of 0.91.

[Resin Synthesis Example 7] (Comparative Resin Synthesis Example 1)
3-methacryloxypropyltris (trimethylsiloxy) silane Silaplane TM-0701T (manufactured by Chisso Corporation) and 3-methacryloxypropyltrimethoxysilane were added to 422 g (1000 mmol) and 0 g (0 mmol), respectively. Obtained resin 7 in the same manner as in resin 1. Resin 7 had a weight average molecular weight of 37,000. Moreover, the resin 7 solution diluted with toluene so that the nonvolatile content was 25% by mass had a viscosity of 8.4 mm ² / sec and a specific gravity of 0.91.

[Resin Synthesis Example 8] (Comparative Resin Synthesis Example 2)
3-methacryloxypropyltris (trimethylsiloxy) silane Silaplane TM-0701T (manufactured by Chisso Corporation) and 3-methacryloxypropyltrimethoxysilane were added to 0 g (0 mmol) and 248 g (1000 mmol), respectively. Produced resin 8 in the same manner as resin 1. Resin 8 had a weight average molecular weight of 33,000. Further, the resin 8 solution diluted with toluene so that the nonvolatile content was 25% by mass had a viscosity of 8.7 mm ² / sec and a specific gravity of 0.90.

[Resin Synthesis Example 9] (Comparative Resin Synthesis Example 3)
100 parts of methyl ethyl ketone was put into a flask equipped with a stirrer, a condenser, a thermometer, a nitrogen introduction tube, and a dropping device, and the temperature was raised to 80 ° C. in a nitrogen atmosphere. Next, 32.6 parts of mel methacrylate, 2.5 parts of 2-hydroxyethyl methacrylate, 64.9 parts of 3-methacryloxypropyltris (trimethylsiloxy) silane and 1,1′-azobis (cyclohexane-1-carbohydrate) A solution of 1 part of nitrile) dissolved in 100 parts of methyl ethyl ketone was added dropwise over 2 hours and aged for 5 hours to obtain Resin 9. Resin 9 had a weight average molecular weight of 45,000. Moreover, the resin 9 solution diluted with toluene so that the nonvolatile content was 25% by mass had a viscosity of 9.4 mm ² / sec and a specific gravity of 0.94.

[Resin Synthesis Example 10] (Comparative Resin Synthesis Example 4)
3-methacryloxypropyltris (trimethylsiloxy) silane Silaplane TM-0701T (manufactured by Chisso Corporation), 3-methacryloxypropyltrimethoxysilane and methyl methacrylate were added in amounts of 211 g (500 mmol) and 0 g (0 mmol), respectively. And Resin 10 was obtained in the same manner as Resin 6 except that the content was changed to 50.0 g (500 mmol). Resin 10 had a weight average molecular weight of 34,000. Further, the resin 10 solution diluted with toluene so that the nonvolatile content was 25% by mass had a viscosity of 8.7 mm ² / sec and a specific gravity of 0.91.

[Resin Synthesis Example 11] (Comparative Resin Synthesis Example 5)
3-methacryloxypropyltris (trimethylsiloxy) silane Silaplane TM-0701T (manufactured by Chisso Corporation), 3-methacryloxypropyltrimethoxysilane and methyl methacrylate were added in amounts of 0 g (0 mmol) and 124.0 g, respectively. Resin 11 was obtained in the same manner as Resin 6 except that the amount was changed to 500 mmol) and 50.0 g (500 mmol). The resin 11 had a weight average molecular weight of 32,000. Moreover, the resin 11 solution diluted with toluene so that the nonvolatile content was 25% by mass had a viscosity of 8.5 mm ² / sec and a specific gravity of 0.89.

[Production example of tin oxide fine particles]
After tin oxide fine powder having a BET surface area of 5 m ² / g is immersed in ethanol, it is heated in a nitrogen atmosphere and maintained at a temperature of 250 ° C. for 1 hour to perform surface modification treatment, thereby obtaining tin oxide fine particles 1. It was.

[Example of carrier production]
[Carrier Production Example 1]
A methacrylic copolymer (100 parts) having a weight average molecular weight of 35,000 obtained in Synthesis Example 1 and 4 parts of titanium diisopropoxybis (ethylacetoacetate) TC-750 (manufactured by Matsumoto Fine Chemical Co., Ltd.) as a catalyst were added to toluene. To obtain a resin solution having a solid content of 10 wt%.
Using Mn ferrite particles having a weight average particle diameter of 35 μm as the core material, using a fluidized bed type coating apparatus so that the average film thickness is 0.20 μm on the surface of the core material, Application and drying were controlled at 70 ° C. The obtained carrier was baked in an electric furnace at 180 ° C./2 hours to obtain carrier A.

[Carrier Production Example 2]
Carrier B corresponding to Carrier Production Example 2 was obtained in exactly the same manner as Carrier Production Example 1 except that the resin was changed to the resin of Synthesis Example 2.

[Carrier Production Example 3]
Carrier C corresponding to Carrier Production Example 3 was obtained in exactly the same manner as Carrier Production Example 1 except that the resin was changed to the resin of Synthesis Example 3.

[Carrier Production Example 4]
Carrier D corresponding to Carrier Production Example 4 was obtained in exactly the same manner as Carrier Production Example 1 except that the resin was changed to the resin of Synthesis Example 4.

[Carrier Production Example 5]
Carrier E corresponding to Carrier Production Example 5 was obtained in exactly the same manner as Carrier Production Example 1 except that the resin was changed to the resin of Synthesis Example 5.

[Carrier Production Example 6]
Carrier F corresponding to Carrier Production Example 6 was obtained in exactly the same manner as Carrier Production Example 1 except that the resin was replaced with the resin of Synthesis Example 6.

[Carrier Production Example 7]
Carrier G corresponding to Carrier Production Example 7 was obtained in exactly the same manner as Carrier Production Example 1 except that the catalyst was changed to titanium diisopropoxybis (triethanolaminate) TC-400 (Matsumoto Fine Chemical Co., Ltd.).

[Carrier Production Example 8]
Carrier H corresponding to Carrier Production Example 8 was obtained in exactly the same manner as Carrier Production Example 2, except that the catalyst was changed to titanium diisopropoxybis (triethanolaminate) TC-400 (Matsumoto Fine Chemical Co., Ltd.).

[Carrier Production Example 9]
Carrier I corresponding to Carrier Production Example 9 was obtained in exactly the same manner as Carrier Production Example 3, except that the catalyst was changed to titanium diisopropoxybis (triethanolaminate) TC-400 (Matsumoto Fine Chemical Co., Ltd.).

[Carrier Production Example 10]
Carrier J corresponding to Carrier Production Example 10 was obtained in exactly the same manner as Carrier Production Example 4 except that the catalyst was changed to titanium diisopropoxybis (triethanolaminate) TC-400 (Matsumoto Fine Chemical Co., Ltd.).

[Carrier Production Example 11]
Carrier K corresponding to Carrier Production Example 11 was obtained in exactly the same manner as Carrier Production Example 5 except that the catalyst was changed to titanium diisopropoxybis (triethanolaminate) TC-400 (Matsumoto Fine Chemical Co., Ltd.).

[Carrier Production Example 12]
Carrier L corresponding to Carrier Production Example 12 was obtained in exactly the same manner as Carrier Production Example 6, except that the catalyst was changed to titanium diisopropoxybis (triethanolaminate) TC-400 (Matsumoto Fine Chemical Co., Ltd.).

[Carrier Production Example 13]
A methacrylic copolymer (100 parts) having a weight average molecular weight of 34,000 obtained in Synthesis Example 6, 4 parts of titanium diisopropoxybis (ethylacetoacetate) TC-750 (manufactured by Matsumoto Fine Chemical Co., Ltd.) as a catalyst, and conductivity 80 parts of oxygen-deficient tin oxide-coated barium sulfate powder (product name: Pastorran 4310, manufactured by Mitsui Kinzoku Co., Ltd.) was diluted with toluene to obtain a resin solution having a solid content of 10 wt%.
Using Mn ferrite particles having a weight average particle diameter of 35 μm as the core material, using a fluidized bed type coating apparatus so that the average film thickness is 0.20 μm on the surface of the core material, Application and drying were controlled at 70 ° C. The obtained carrier was baked in an electric furnace at 180 ° C./2 hours to obtain carrier M.

[Carrier Production Example 14]
Carrier N corresponding to carrier production example 12 was obtained in exactly the same manner as carrier production example 6, except that the conductive fine particles were replaced with tin oxide fine particles 1 obtained in the tin oxide fine particle synthesis example.

[Carrier Production Comparative Example 1]
Carrier O corresponding to Carrier Production Comparative Example 1 was obtained in exactly the same manner as Carrier Production Example 1 except that the resin was replaced with Resin 7 of Synthesis Comparative Example 1.

[Carrier Production Comparative Example 2]
A carrier P corresponding to Carrier Production Comparative Example 2 was obtained in exactly the same manner as Carrier Production Example 1 except that the resin was changed to Resin 8 of Synthesis Comparative Example 2.

[Carrier Production Comparative Example 3]
With respect to the resin 9 obtained in Resin Synthesis Comparative Example 3, isophorone diisocyanate / trimethylolpropane adduct (IPDI / TMP system: NCO% = 6.1%) was used as a crosslinking agent in an OH / NCO molar ratio (OH was synthesized). The resin in Example 10 (OH) was adjusted to 1/1 and diluted with MEK to prepare a coating resin solution having a solid ratio of 3% by weight.
Using Mn ferrite particles having a weight average particle diameter of 35 μm as the core material, using a fluidized bed type coating apparatus so that the average film thickness is 0.20 μm on the surface of the core material, Application and drying were controlled at 70 ° C. The obtained carrier was baked in an electric furnace at 180 ° C./2 hours to obtain carrier Q.

[Carrier Production Comparative Example 4]
Carrier R corresponding to Carrier Production Comparative Example 4 was obtained in exactly the same manner as Carrier Production Example 1 except that the resin was changed to Resin 10 of Synthesis Comparative Example 4.

[Carrier Production Comparative Example 5]
Carrier S corresponding to Carrier Production Comparative Example 5 was obtained in exactly the same manner as Carrier Production Example 1 except that the resin was changed to Resin 11 of Synthesis Comparative Example 5.

[Carrier Production Comparative Example 6]
Except for adding 30 parts of a methyl silicone resin (solid content 25%) having a weight average molecular weight of 15,000 made from a bifunctional to trifunctional monomer, the same procedure as in Carrier Production Example 1 was used. Carrier T was obtained.

[Carrier property evaluation]
Hereinafter, a method for evaluating carrier characteristics will be described.

[Weight average particle diameter of core particles]
The particle size distribution of the core particles was measured using a Microtrac particle size distribution model HRA9320-X100 (manufactured by Nikkiso Co., Ltd.).

[Magnetization in a magnetic field of 1 kOe]
About 0.15 g of carrier is filled in a cell with an inner diameter of 2.4 mm and a height of 8.5 mm, and then magnetization is measured in a magnetic field of 1 kOe using VSM-P7-15 (manufactured by Toei Kogyo Co., Ltd.). did.

[Volume resistivity]
The volume resistivity was measured using the cell shown in FIG. Specifically, first, a carrier (3) is placed in a cell composed of a fluororesin container (2) in which an electrode (1a) and an electrode (1b) having a surface area of 2.5 cm × 4 cm are accommodated at a distance of 0.2 cm. And tapping was performed 10 times at a drop height of 1 cm and a tapping speed of 30 times / minute. Next, a resistance r [Ω] 30 seconds after applying a DC voltage of 1000 V between the electrodes (1a) and (1b) was measured using a high resistance meter 4329A (manufactured by Yokogawa Hewlett Packard). From the following [Equation 1], the volume resistivity [Ωcm] was calculated.

[Average film thickness of coating layer]
Using a transmission electron microscope (TEM), the cross section of the carrier was observed, and the average film thickness of the coating layer was measured. The characteristics of the obtained carrier are shown in Table 1.

[Measurement of Ba / Si]
The ratio of the content of Ba and Si in the carrier M, Ba / Si, was measured using an X-ray electron spectrometer (XPS). Details are described below.
Measuring device: AXIS-ULTRA manufactured by Kratos
Measurement light source: Al (monochromator)
Measurement output: 90 W (15 kV, 6 mA)
Measurement area: 900 × 600 (μm ² )
Pass energy: (wide scan) 160eV, (narrow scan) 40eV
Energy step: (wide scan) 1.0 eV, (narrow scan) 0.2 eV
Relative sensitivity coefficient: Uses Kratos' relative sensitivity coefficient Because it is a magnetic substance, measurement is performed with MAGNET CONTROLLER turned off.
In the measurement, the sample was put into a cylindrical hole with a depth of 0.3 mm and a flat part of the surface was measured. The measurement result was expressed in atomic% (number), and Ba / Si was calculated using the ratio of the measurement values. The Ba / Si of carrier M was 0.077.

[Example of toner production]
[Synthesis Example of Polyester Resin A]
443 parts of PO adduct of bisphenol A (hydroxyl value 320), 135 parts of diethylene glycol, 422 parts of terephthalic acid, and 2.5 parts of dibutyltin oxide are placed in a reaction vessel equipped with a thermometer, stirrer, cooler and nitrogen introduction tube. Then, the reaction was carried out at 200 ° C. until the acid value reached 10 to obtain [Polyester Resin A]. The resin had a Tg of 63 ° C. and a peak number average molecular weight of 6000.

[Synthesis example of polyester resin B]
443 parts of PO adduct of bisphenol A (hydroxyl value 320), 135 parts of diethylene glycol, 422 parts of terephthalic acid, and 2.5 parts of dibutyltin oxide are placed in a reaction vessel equipped with a thermometer, stirrer, cooler and nitrogen introduction tube. Then, the reaction was carried out at 230 ° C. until the acid value became 7, to obtain [Polyester Resin B]. The resin had a Tg of 65 ° C. and a peak number average molecular weight of 16000.

Polyester resin A ... 40 parts Polyester resin B ... 60 parts Carnauba wax ... 1 part Carbon black (# 44 manufactured by Mitsubishi Chemical Corporation) ... 10 parts Mixing is performed with a mixer (Henschel 20B manufactured by Mitsui Mining Co., Ltd., at 1500 rpm for 3 minutes), and kneading is performed under the following conditions using a single-screw kneader (Buss small bus co-kneader) (set temperature: inlet 100) The feed amount: 2 kg / Hr) and [base toner A1] were obtained.
Further, the [base toner A1] was kneaded and then cooled by rolling, pulverized by a pulverizer, and further an I-type mill (IDS-2 type manufactured by Nippon Pneumatic Co., Ltd., using a flat impact plate, air pressure: 6.8 atm). / Cm ² , feed amount: 0.5 kg / hr) was finely pulverized, and further classified (132MP manufactured by Alpine) to obtain [base toner particles 1].

(External additive treatment)
To 100 parts of “base toner particle 1”, 1.0 part of hydrophobic silica fine particles (R972: manufactured by Nippon Aerosil Co., Ltd.) was added as an external additive and mixed with a Henschel mixer to obtain toner particles (hereinafter “toner toner”). 1 ”).

[Create developer]
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.
To the carriers A to R (93 parts) obtained in the carrier production example, 7.0 parts of the toner 1 (7.2 μm) obtained in the toner production example was added and stirred for 20 minutes with a ball mill. Developers A to R were prepared.

[Developer characteristics evaluation]
Using the obtained developer, image evaluation was performed using a digital full-color multifunction peripheral, Image Neo C600 (manufactured by Ricoh). Specifically, first, using the developers A to H of the examples and the comparative examples and the toner 1 of the examples, the charge amount of the carrier after the initial and 100,000 sheets running at an image area ratio of 20% and The volume resistivity was measured, and the amount of decrease in charge amount and the amount of change in volume resistivity were calculated.
The initial charge amount (Q1) of the carrier was determined by mixing a carrier A to T and the toner 1 of the example at a mass ratio of 93: 7, and triboelectrically charging a sample with a blow-off device TB-200 (Toshiba Chemical). The measurement was performed using The charge amount (Q2) of the carrier after running was measured in the same manner as described 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 target value of the change amount of the charge amount is 10 μC / g or less.
On the other hand, the volume specific resistance (LogR1) of the initial carrier is a common logarithmic value of the volume specific resistance of the carrier measured in the same manner as [Volume Specific Resistance]. The volume resistivity (LogR2) of the carrier after running was measured in the same manner as described 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 target value of the volume resistivity is 1.5 [Log (Ωcm)] or less in absolute value. Table 2 shows the developer evaluation results.

(Figure 1)
1a Electrode 1b Electrode 2 Fluororesin container 3 Carrier (FIG. 2)
10 Process Cartridge 11 Photoconductor 12 Charging Device 13 Developing Device 14 Cleaning Device

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

Claims (21)

An electrostatic latent image developer carrier comprising magnetic core particles and a resin layer covering the surface thereof, wherein the resin layer is derived from at least the monomer A component represented by the following general formula (1) And a resin obtained by heat-treating a copolymer containing the A portion and the B portion derived from the monomer B component represented by the following general formula (2). A carrier for an electrostatic latent image developer, comprising a crosslinked product obtained by hydrolyzing a polymer to form a silanol group and condensing using an organic titanium system.

(In the formula, R ¹ , m, R ² , R ³ , X, and Y are as follows.)
R ¹ : hydrogen atom, or methyl group m: alkylene group having 1 to 8 carbon atoms R ² : alkyl group having 1 to 4 carbon atoms R ³ is an alkyl group having 1 to 8 carbon atoms, or 1 to 1 carbon atoms 4 alkoxy group X: 10 to 90 mol%
Y: 10 to 90 mol%. The carrier for an electrostatic latent image developer according to claim 1, wherein the copolymer includes a copolymer represented by the following general formula (5).

(In the formula, R ¹ , m, R ² , R ³ , X, Y, and Z are as follows.)
R ¹ : hydrogen atom or methyl group m: an alkylene group having 1 to 8 carbon atoms R ² : an alkyl group having 1 to 4 carbon atoms R ³ : an alkyl group having 1 to 8 carbon atoms, or 1 to 4 carbon atoms Alkoxy group X: 10 to 40 mol%
Y: 10 to 40 mol%
Z: 30 to 80 mol%
60 mol% <Y + Z <90 mol%.   The carrier for an electrostatic latent image developer according to claim 1, wherein the organic titanium-based catalyst is a titanium alkoxide.   The carrier for an electrostatic latent image developer according to claim 1, wherein the organic titanium-based catalyst is a titanium chelate.   The carrier for an electrostatic latent image developer according to any one of claims 1 to 4, wherein the carrier is obtained by coating the coating layer and then heating.   The carrier for an electrostatic latent image developer according to any one of claims 1 to 5, wherein a heat treatment temperature during the heat treatment is 100 to 350 ° C.   The carrier for an electrostatic latent image developer according to claim 1, wherein the coating layer further contains conductive particles.   8. The electrostatic latent image developer carrier according to claim 1, wherein the conductive particles are conductive fine particles containing at least barium sulfate.   The ratio of the content of Ba and Si to all elements measured by X-ray photoelectron spectroscopy (XPS), Ba / Si, is 0.01 or more and 0.08 or less, characterized in that it is 1 to 8 The carrier for an electrostatic latent image developer according to any one of the above.   The carrier for an electrostatic latent image developer according to claim 7, wherein the conductive particles are tin oxide fine particles having carbon on the surface. 11. The electrostatic latent image developer carrier according to claim 1, wherein the volume resistivity is 1 × 10 ⁹ Ω · cm to 1 × 10 ¹⁷ Ω · cm.   The carrier for an electrostatic latent image developer according to claim 1, wherein the coating layer has an average film thickness of 0.05 μm to 4 μm.   13. The carrier for an electrostatic latent image developer according to claim 1, wherein the core material particles have a weight average particle diameter of 20 μm or more and 65 μm or less. The carrier for an electrostatic latent image developer according to claim 1, wherein magnetization in a magnetic field of 1 kOe is 40 Am ² / kg or more and 90 Am ² / kg or less.   A developer comprising the carrier and the toner according to claim 1.   The developer according to claim 15, wherein the toner is a color toner.   A replenishment developer containing 2 to 50 parts by weight of toner with respect to 1 part by mass of the carrier, wherein the carrier is the carrier according to any one of claims 1 to 14. Replenishment developer. A method for producing a carrier having a step of forming a coating layer on the surface of a core particle, wherein the coating step includes an A site derived from a monomer A component represented by the following general formula (1) and the following general formula (2 The coating layer containing a cross-linked product obtained by hydrolyzing a copolymer containing a B site derived from the monomer B component represented by formula (II) to produce a silanol group and condensing using an organic titanium catalyst. A method for producing a carrier, which is a step of forming a film.

(In the formula, R ¹ , m, R ² , R ³ , X, and Y are as follows.)
R ¹ : hydrogen atom, or methyl group m: alkylene group having 1 to 8 carbon atoms R ² : alkyl group having 1 to 4 carbon atoms R ³ is an alkyl group having 1 to 8 carbon atoms, or 1 to 1 carbon atoms 4 alkoxy group X: 10 to 90 mol%
Y: 10 to 90 mol%.   A developer-containing container comprising the developer according to claim 15.   A developer according to any one of claims 15 to 17, comprising: forming an electrostatic latent image on the electrostatic latent image carrier; and forming the electrostatic latent image on the electrostatic latent image carrier. Developing the toner image to form a toner image; transferring the toner image formed on the electrostatic latent image carrier to a recording medium; fixing the toner image transferred to the recording medium; An image forming method comprising:   An electrostatic latent image carrier and means for developing the electrostatic latent image formed on the electrostatic latent image carrier using the developer according to any one of claims 15 to 17 are at least integrally supported. A process cartridge characterized by

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