JP2012058401A - Developer for electrostatic charge image development, developing device, image forming apparatus, image forming method, and process cartridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a carrier having an excellent toner spent property and abrasion resistance (chipping and peeling) of a coating, developer having the carrier, a container including the developer, and an image forming method and a process cartridge using the developer.SOLUTION: A carrier for an electrostatic latent image developer formed of magnetized core material particles and a resin layer that coats the surface of the particles. The resin layer includes resin obtained by subjecting a copolymer including a tris (trialkylsiloxy) silane and a radical polymerizable silane to heating treatment, as well as conductive particulates formed of cerium oxide.

Description

  The present invention relates to a carrier having a coating layer formed on the surface of core material particles, 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.

  As an example of a carrier coated with a resin having a low surface energy, Japanese Patent Application Laid-Open No. 55-127469 of Patent Document 1 describes a carrier coated with a room temperature curable silicone resin and a positively chargeable nitrogen resin. 2 discloses a carrier coated with a coating material containing at least one modified silicone resin, and Japanese Patent Application Laid-Open No. 56-140358 discloses a room temperature curing type. A carrier having a resin coating layer containing a silicone resin and a styrene / acrylic resin is described. In JP-A-57-96355 of Patent Document 4, a core particle surface is coated with two or more layers of a silicone resin, Describes a carrier that has no adhesiveness, and Japanese Patent Application Laid-Open No. 57-96356 of Patent Document 5 discloses a silicone resin on the surface of core particles. JP-A-58-207054 of Patent Document 6 describes a carrier whose surface is coated with a silicone resin containing silicon carbide, and JP-A 61-110161 of Patent Document 7. Describes a positively chargeable carrier coated with a material exhibiting a critical surface tension of 20 dyn / cm or less, and Japanese Patent Application Laid-Open No. 62-273576 of Patent Document 8 discloses a coating material containing a fluorine alkyl acrylate. And a developer comprising a carrier coated with 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. A coating of particles is disclosed, and as an example of a titanium-based catalyst, diisopropoxybis (acetylacetonate) (shown in Preparation Example 1 described herein) is tetraisopropoxytitanium, Isopropoxy (2-ethylhexanediolato) titanium, bis (acryloyloxy) isopropoxyisostearoyloxytitanium Bis (2,4-pentanedionato) (1,3-propanedionato isocyanatomethyl) are enumerated as being the 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)-(16).
(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 an A portion represented by the following general formula (1) And a resin obtained by heat-treating a copolymer containing a B portion represented by the following general formula (2), characterized in that it contains conductive fine particles made of cerium oxide. Carrier for electrostatic latent image developer.

（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（３）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 : a hydrogen atom or a 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 is an alkyl group having 1 to 8 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms,
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 (3).

（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％。
（３）前記被服層中に含まれる前記導電性微粒子はキャリア芯材に対して被覆率が１０〜８０％であることを特徴とする前記（１）項又は（２）項のいずれかに記載の静電潜像現像剤用キャリア。
（４）前記酸化セリウムからなる導電性粒子を含有する前記共重合体の樹脂層を前記芯材粒子に被覆して、しかる後に加熱処理して得られたことを特徴とする前記（１）項乃至（３）項のいずれかに記載の静電潜像現像剤用キャリア。
（５）前記加熱処理時の熱処理温度が１００〜３５０℃であることを特徴とする前記（１）項乃至（４）項のいずれかに記載の静電潜像現像剤用キャリア。
（６）体積固有抵抗が１×１０^８Ω・ｃｍ以上１×１０^１７Ω・ｃｍ以下であることを特徴とする前記（１）乃至（５）項のいずれかに記載の静電潜像現像剤用キャリア。
（７）前記被覆層は、平均膜厚が０．０５μｍ以上４μｍ以下であることを特徴とする前記（１）項乃至（６）項のいずれかに記載の静電潜像現像剤用キャリア。
（８）前記芯材粒子は、重量平均粒径が２０μｍ以上６５μｍ以下であることを特徴とする前記（１）項乃至（７）項のいずれかに記載の静電潜像現像剤用キャリア。
（９）１ｋＯｅの磁場における磁化が４０Ａｍ^２／ｋｇ以上９０Ａｍ^２／ｋｇ以下であることを特徴とする前記（１）項乃至（８）項のいずれかに記載の静電潜像現像剤用キャリア。
（１０）前記（１）項乃至（９）項のいずれか一項に記載のキャリア及びトナーを有することを特徴とする現像剤。
（１１）前記トナーは、カラートナーであることを特徴とする前記（１０）項に記載の現像剤。
（１２）磁性を有する芯材粒子と該芯材粒子表面を被覆する被覆層を形成する工程を有するキャリアの製造方法であって、該樹脂層は、少なくとも一般式（１）で表されるＡ部分と一般式（２）で表されるＢ部分とを含む共重合体を加熱処理して得られた樹脂を含有するものであり、酸化セリウムからなる導電性微粒子を含有することを特徴とするキャリアの製造方法。

(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: 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 an alkoxy group having 1 to 4 carbon atoms,
X: 10 to 40 mol%,
Y: 10 to 40 mol%,
Z: 30 to 80 mol%,
60 mol% <Y + Z <90 mol%.
(3) The conductive fine particles contained in the clothing layer have a coverage of 10 to 80% with respect to the carrier core material. Carrier for electrostatic latent image developer.
(4) Item (1) above, obtained by coating the core resin particles with the resin layer of the copolymer containing the conductive particles made of the cerium oxide, and thereafter heat-treating the core particles. The carrier for an electrostatic latent image developer according to any one of items (3) to (3).
(5) The electrostatic latent image developer carrier according to any one of (1) to (4) above, wherein a heat treatment temperature during the heat treatment is 100 to 350 ° C.
(6) The electrostatic latent image development according to any one of (1) to (5) above, wherein the volume resistivity is 1 × 10 ⁸ Ω · cm or more and 1 × 10 ¹⁷ Ω · cm or less. Agent carrier.
(7) The carrier for an electrostatic latent image developer according to any one of (1) to (6), wherein the coating layer has an average film thickness of 0.05 μm to 4 μm.
(8) The carrier for an electrostatic latent image developer according to any one of (1) to (7), wherein the core material particles have a weight average particle diameter of 20 μm to 65 μm.
(9) The carrier for an electrostatic latent image developer according to any one of (1) to (8) above, wherein magnetization in a magnetic field of 1 kOe is 40 Am ² / kg or more and 90 Am ² / kg or less. .
(10) A developer comprising the carrier and toner according to any one of (1) to (9).
(11) The developer as described in (10) above, wherein the toner is a color toner.
(12) A method for producing a carrier comprising a step of forming a core material particle having magnetism and a coating layer covering the surface of the core material particle, wherein the resin layer is at least represented by A represented by the general formula (1) Containing a resin obtained by heat-treating a copolymer containing a portion and a B portion represented by the general formula (2), characterized by containing conductive fine particles made of cerium oxide Carrier manufacturing method.

（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％。
（１３）前記（１０）項又は（１１）項に記載の現像剤を有することを特徴とする現像剤入り容器。
（１４）静電潜像担持体上に静電潜像を形成する工程と、該静電潜像担持体上に形成された静電潜像を、前記（１０）項又は（１１）項に記載の現像剤を用いて現像してトナー像を形成する工程と、該静電潜像担持体上に形成されたトナー像を記録媒体に転写する工程と、該記録媒体に転写されたトナー像を定着させる工程とを有することを特徴とする画像形成方法。
（１５）静電潜像担持体、該静電潜像担持体上に形成された静電潜像を、前記（１０）項又は（１１）項に記載の現像剤を用いて現像する手段が少なくとも一体に支持されていることを特徴とするプロセスカートリッジ。
（１６）キャリア１質量部に対してトナーを２〜５０重量部の配合割合で含有する補給用現像剤であって、該キャリアが前記（１）項乃至（９）項のいずれかに記載のキャリアであることを特徴とする補給用現像剤。

(In the formula, R ¹ , m, R ² , R ³ , X, and Y are as follows.)
R ¹ : a hydrogen atom or a 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 is an alkyl group having 1 to 8 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms,
X: 10 to 90 mol%,
Y: 10 to 90 mol%.
(13) A developer-containing container comprising the developer according to (10) or (11).
(14) 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 described in the above item (10) or (11). Developing with 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 toner image transferred to the recording medium An image forming method comprising: fixing the toner.
(15) An electrostatic latent image carrier, and means for developing the electrostatic latent image formed on the electrostatic latent image carrier using the developer described in (10) or (11). A process cartridge which is supported at least integrally.
(16) 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 (9). A developer for replenishment characterized by being a carrier.

  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 with drawing.
That is, the carrier of the present invention is obtained by radical copolymerizing the monomer A component for the A portion represented by the following general formula (1) and the monomer B component for the B portion represented by the following structural formula 2. It is a carrier for developing an electrostatic latent image obtained by coating a resin layer composition containing the obtained acrylic copolymer and then heat-treating it.

The resin that covers the surface of the core particle will be described.
Resin that coats the surface of the core particle includes an A part represented by the following general formula (1) and a B part represented by the following general formula (2), and the monomer A component and the B part for the A part It is a resin obtained by heat-treating after coating an acrylic copolymer obtained by radical copolymerization of the monomer B component.
Part A (and monomer A component for it):

前式中、
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のアルキル基であり、メチル基、エチル基、プロピル基、及びブチル基

In the previous formula,
R ¹ : hydrogen atom, or 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 having 1 to 4 carbon atoms, methyl group, ethyl group, propyl group, and butyl group

In A part (and monomer A component), it is 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 tris (trimethylsiloxy) silane having a large number of methyl groups in the side chain, and the ratio of the A portion (monomer A component) to the entire resin increases. The surface energy is reduced and adhesion of toner resin components, wax components, and the like is reduced. If the A portion (monomer A component) is less than 10 mol%, a sufficient effect cannot be obtained, and adhesion of the toner component increases rapidly. Moreover, when it exceeds 90 mol%, while B part (monomer B component) and toughness are insufficient, the adhesiveness of a core material and a resin layer falls, and durability of a carrier film worsens.

R ² is an alkyl group having 1 to 4 carbon atoms, and examples of the monomer A component generating such an A moiety include tris (trialkylsiloxy) silane compounds 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 component A for the A portion is not particularly limited, but a method of reacting tris (trialkylsiloxy) silane with allyl acrylate or allyl methacrylate in the presence of a platinum catalyst, or JP-A-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.

  B part (and monomer B component / precursor monomer B): (crosslinking component)

前式中、
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のアルキル基であり、メチル基、エチル基、プロピル基、及びブチル基
Ｒ^３：炭素数１〜８のアルキル基（メチル基、エチル基、プロピル基、ブチル基など）、又は炭素数１〜４のアルコキシ基（メトキシ基、エトキシ基、プロポキシ基、ブトキシ基）。
即ち、Ｂ部分のためのモノマーＢ成分は、ラジカル重合性の２官能（Ｒ^３がアルキル基の場合）、又は３官能性（Ｒ^３もアルコキシ基の場合）のシラン化合物であり、Ｙ＝１０〜９０モル％であるが、好ましくは１０〜８０モル％であり、より好ましくは１５〜７０モル％である。
Ｂ成分が１０モル％未満だと、強靭さが十分得られない。一方、９０モル％より多いと、被膜は固くて脆くなり、膜削れが発生し易くなる。また、環境特性が悪化する。加水分解した架橋成分がシラノール基として多数残り、環境特性（湿度依存性）を悪化させていることも考えられる。

In the previous formula,
R ¹ : hydrogen atom or 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 having 1 to 4 carbon atoms, methyl group, ethyl group, 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).
That is, the monomer B component for the B portion is a radical polymerizable bifunctional (when R ³ is an alkyl group) or a trifunctional (when R ³ is also an alkoxy group) silane compound, and Y = 10 Although it is -90 mol%, Preferably it is 10-80 mol%, More preferably, it is 15-70 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 the monomer B component include 3-methacryloxypropyltrimethoxysilane, 3-acryloxypropyltrimethoxysilane, 3-methacryloxypropyltriethoxysilane, 3-acryloxypropyltriethoxysilane, and 3-methacryloxypropyl. Examples include methyldimethoxysilane, 3-methacryloxypropylmethyldiethoxysilane, 3-methacryloxypropyltri (isopropoxy) silane, and 3-acryloxypropyltri (isopropoxy) silane.

Japanese Patent No. 3691115 discloses a technique for improving durability by crosslinking a coating.
In this patent 3691115, the magnetic particle surface has 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. Although a carrier for developing an electrostatic image is described in which a copolymer with a radical copolymerizable monomer is coated with a thermosetting resin crosslinked with an isocyanate-based compound, it has sufficient durability in peeling and scraping of the film. 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 The structure cannot be formed, and therefore, when 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.

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 the film is crosslinked by condensation polymerization, it is considered that the coating is extremely tough and difficult to scrape, so that high durability is achieved.
Further, it is presumed that the aging stability of the coating is maintained since the crosslinking by the siloxane bond of the present invention has a larger binding energy and is more stable against heat stress than the crosslinking by the isocyanate compound.

In the present invention, in order to provide 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 (3). C portion can be included.
C part (and monomer C component): (acrylic component)

前式中、
Ｒ^１：水素原子、またはメチル基
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アクリロイル基、またはメタアクリロイル基を有するラジカル重合性アクリル系化合物である。

In the previous formula,
R ¹ : a hydrogen atom or a methyl group R ² : an aliphatic hydrocarbon group having 1 to 4 carbon atoms, having an acryloyl group or a methacryloyl group that is a methyl group, an ethyl group, a propyl group, or a butyl group It is a radically polymerizable acrylic compound.

The content of the A part (monomer A component) and the B part (monomer B component) in the case of containing the C component is X = 10-40 mol%, Y = 10-40 mol%, The content of (monomer C component) is Z = 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%.
If the C part (monomer C component) is greater than 80 mol%, either X or Y will be 10 or less, making it difficult to achieve both water repellency, hardness and flexibility (film scraping) of the carrier film. Become.

  As the acrylic compound (monomer) of the monomer C component for the C portion, 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 is 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 in the present invention is an acrylic copolymer obtained by radical copolymerization of the monomers A and B for the A portion and the B portion, and has many crosslinkable functional groups per unit weight of the resin. In addition to the above, since the crosslinking component B is subjected to condensation polymerization by heat treatment and crosslinked, it is considered that the resin layer is extremely tough and difficult to scrape and is highly durable.
In addition, it is surmised that the cross-linking by the siloxane bond in the present invention has higher binding energy and is more stable against heat stress than the cross-linking by the isocyanate compound, so that the stability of the resin layer with time is maintained. .

The resin layer composition of the present invention preferably contains a silicone resin having a silanol group and / or a functional group capable of generating a silanol group by hydrolysis.
A silicone resin having a silanol group and / or a functional group capable of generating a silanol group by hydrolysis (eg, a negative group such as an alkoxy group or a halogeno group bonded to a Si atom) is a copolymer of the above-mentioned copolymer The crosslinking component B can be subjected to condensation polymerization directly or with the crosslinking component B in a state of being converted to a silanol group. The toner spent property is further improved by adding a silicone resin component to the copolymer.

  In the present invention, the silicone resin having a silanol group used when forming the resin layer and / or a functional group capable of generating a silanol group by hydrolysis is represented by the following general formula (I). It preferably contains at least one repeating unit.

Here, in the above formula (I), A ¹ is 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). ² is an alkylene group having 1 to 4 carbon atoms or an arylene group (such as a phenylene group).

  In the aryl group of the above formula, the carbon number thereof is 6 to 20, preferably 6 to 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. Examples of the arylene group include 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 aromatic such as biphenyl and terphenyl. An arylene group derived from a group hydrocarbon is included. The arylene group may be substituted with various substituents.

  Although it does not specifically limit as a commercial item of the silicone resin which can be used for this invention, KR251, KR271, KR272, KR282, KR252, KR255, KR152, KR155, KR211, KR216, KR213 (above, the Shin-Etsu Silicone company make), 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.
As a weight average molecular weight of a silicone resin, it is 1,000-100,000, Preferably, it is about 1000-30000. 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 resin layer may not be sufficiently increased after curing. If it is less than 1,000, problems such as brittleness of the cured resin layer tend to occur.

The content ratio of the silicone resin is 5% by weight to 80% by weight, preferably 10% by weight to 60% by weight with respect to the copolymer.
When the amount is less than 5% by weight, the effect of improving the spent property or the like cannot be obtained.
In the present invention, a silane coupling agent can also be used to improve the dispersibility of the conductive fine particles and adjust the toner charge amount.
In particular, it is effective to contain an appropriate amount (0.001 to 30% by weight) of the aminosilane coupling agent shown below for the silicone resin in order to adjust the toner charge amount.

Examples of the aminosilane coupling agent include the following.
H ₂ N (CH ₂ ) ₃ Si (OCH ₃ ) ₃ MW 179.3
_{H 2 N (CH 2) 3} Si (OC 2 H 5) 3 MW 221.4
_{H 2 NCH 2 CH 2 CH 2} Si (CH 3) 2 (OC 2 H 5) MW 161.3
_{H 2 NCH 2 CH 2 CH 2} Si (CH 3) (OC 2 H 5) 2 MW 191.3
H ₂ NCH ₂ CH ₂ NHCH ₂ Si (OCH ₃ ) ₃ MW 194.3
H ₂ NCH ₂ CH ₂ NHCH ₂ CH ₂ CH ₂ Si (CH ₃ ) (OCH ₃ ) ₂ MW 206.4
H ₂ NCH ₂ CH ₂ NHCH ₂ CH ₂ CH ₂ Si (OCH ₃ ) ₃ MW 224.4
_{(CH 3) 2 NCH 2 CH} 2 CH 2 Si (CH 3) (OC 2 H 5) 2 MW 219.4
_{(C 4 H 9) 2 NC} 3 H 6 Si (OCH 3) 3 MW 291.6

  The resin layer composition of the present invention can also contain a resin other than the silicone resin having the silanol group and / or the hydrolyzable functional group. Such a resin is not particularly limited, but is an acrylic resin. Amino resin, polyvinyl resin, polystyrene resin, halogenated olefin resin, polyester, polycarbonate, polyethylene, polyvinyl fluoride, polyvinylidene fluoride, polytrifluoroethylene, polyhexafluoropropylene, vinylidene fluoride and vinyl fluoride Polymers, fluoroterpolymers such as terpolymers of tetrafluoroethylene, vinylidene fluoride, and non-fluorinated monomers, silicone resins that do not have silanol groups or hydrolyzable functional groups, etc. May be. 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.

The resin layer composition further preferably contains a cross-linked 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. 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 fine particles can further 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.

In order to accelerate the condensation reaction of the crosslinked part B, a titanium-based catalyst, a tin-based catalyst, a zirconium-based catalyst, and an aluminum-based catalyst can be used. Of these various catalysts, titanium alkoxides and titanium chelates are particularly preferred among the titanium-based catalysts that give excellent results.
This is considered to be because the effect of promoting the condensation reaction of the silanol group derived from the crosslinked portion B is large and the catalyst is hardly deactivated. An example of a titanium alkoxide catalyst is titanium diisopropoxybis (ethyl acetoacetate) represented by the following structural formula 5, and an example of a titanium chelate catalyst is represented by the following structural formula 6. Titanium diisopropoxybis (triethanolaminate) is mentioned.

The resin layer includes a copolymer containing the A part and the B part, a titanium diisopropoxybis (ethylacetoacetate) catalyst, and if necessary, a resin other than the copolymer containing the A part and the B part. And a resin layer composition containing a solvent.
Specifically, it may be formed by condensing silanol groups while coating the core material particles with the resin layer composition, or after coating the core material particles with the resin layer composition, It may be formed by condensation.
The method of condensing silanol groups while coating the core material particles with the resin layer composition is not particularly limited, but the method of coating the core particles with the resin layer composition while applying heat, light, etc. Etc. 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 copolymer resin of the present invention preferably has a weight average molecular weight of 5,000 to 100,000, more preferably 10,000 to 70,000, and 30,000 to 40,000. More preferably. If it is less than 5,000, the strength of the resin layer will be insufficient, and if it is 100,000, the liquid viscosity will be high and the carrier productivity will be poor.

In the present invention, it is particularly important to use cerium oxide as the conductive particles. By containing cerium oxide in the coating film, the film becomes difficult to be scraped, and the wear resistance of the carrier is dramatically improved. Further, it is important that the coverage of cerium oxide is 10 to 80% by mass with respect to the amount of the carrier core material. If the coverage is less than 10%, the effect of increasing the film strength is insufficient, and the improvement of the wear resistance of the carrier is limited. If the coverage is more than 80%, the adhesion between the conductive fine particles and the resin is deteriorated, so that the film is easily peeled off.
The cerium oxide particles used in the present invention preferably have a primary average particle size (number average particle size) of 0.1 nm to 4.0 μm.

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. When the average film thickness exceeds 4 μm, the coating layer is not a magnetic substance, and thus the carrier easily adheres to the image.

  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). The volume specific resistance [Ω · cm] can be calculated from the following mathematical formula (1).

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.

  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 using the carrier of the present invention as a replenishment developer composed of a carrier and 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.

<Synthesis of copolymer>
The weight average molecular weight was determined in terms of standard polystyrene using 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.
Nonvolatile content (%) = (weight before heating−weight after heating) × 100 / weight before heating Hereinafter, synthesis examples of resins used in the present invention will be shown.

(Resin synthesis example 1) <Ternary system>
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. Then this
_{CH 2 = CMe-COO-C} 3 H 6 -Si (OSiMe 3) 3 ( wherein, Me is a methyl group.) 3-methacryloxypropyl tris (trimethylsiloxy) silane 84.4 g (200 mmol represented by : Silaplane TM-0701T / manufactured by Chisso Corporation), 3-methacryloxypropylmethyldiethoxysilane 39 g (150 mmol), methyl methacrylate 65.0 g (650 mmol), and 2,2′-azobis-2- A mixture of 0.58 g (3 mmol) of 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). A 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 a methacrylic copolymer.
The weight average molecular weight of the obtained methacrylic copolymer was 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.

(Resin synthesis example 2) <Ternary system>
Radical copolymerization was carried out in exactly the same manner as in Resin Synthesis Example 1, except that 39 g (150 mmol) of 3-methacryloxypropylmethyldiethoxysilane was replaced with 37.2 g (150 mmol) of 3-methacryloxypropyltrimethoxysilane. As a result, a methacrylic copolymer was obtained.
The weight average molecular weight of the obtained methacrylic copolymer was 34,000. 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 8.7 mm ² / s, and the specific gravity was 0.91.

(Resin synthesis example 3) <Binary system>
500 g of toluene was put into a flask equipped with a stirrer, and the temperature was raised to 90 ° C. under a nitrogen gas stream. Next, 3-methacryloxypropyltris (trimethylsiloxy) silane 126. represented by CH ₂ = CMe—COO—C ₃ H ₆ —Si (OSiMe ₃ ) ₃ (wherein Me is a methyl group). 6 g (300 mmol: Silaplane TM-0701T / manufactured by Chisso Corporation), 173.6 g (700 mmol) of 3-methacryloxypropyltrimethoxysilane, and 2,2′-azobis-2-methylbutyronitrile 58 g (3 mmol) of the mixture 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). A 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 a methacrylic copolymer. The weight average molecular weight of the obtained methacrylic copolymer was 35,000.
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 8.5 mm ² / s, and the specific gravity was 0.91.

(Resin synthesis example 4)
100 parts of MEK (methyl ethyl ketone) was charged into a 500 ml flask equipped with a stirrer, a condenser, a thermometer, a nitrogen inlet tube, and a dropping device. Separately, 32.6 parts of MMA (methyl methacrylate), 2.5 parts of HEMA (2-hydroxyethyl methacrylate) and MPTS (organopolysiloxane-1: 3-methacryloxypropyltris (trimethylsiloxy) at 80 ° C. in a nitrogen atmosphere A solution obtained by dissolving 64.9 parts of silane) and 1 part of V-40 (1,1′-azobis (cyclohexane-1-carbonitrile)) in 100 parts of MEK was dropped into the reaction vessel over 2 hours. And aged for 5 hours.
The copolymer solution was diluted with MEK (methyl ethyl ketone) so that the nonvolatile content was 25% by weight.

[Example of carrier production]
(Carrier Production Example 1)
A methacrylic copolymer having a weight average molecular weight of 33,000 (100 parts) obtained in Synthesis Example 1, 0.05 parts of cerium oxide fine particles (manufactured by C.I. Kasei Co., Ltd., primary particle diameter: 12 nm) as conductive fine particles, and titanium dioxide as a catalyst. 4 parts of isopropoxybis (ethylacetoacetate) TC-750 (manufactured by Matsumoto Fine Chemical 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 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 0.05 part of cerium oxide fine particles (CI Chemical Co., Ltd., primary particle diameter 12 nm) was changed to 0.02 part.

(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 0.05 part of cerium oxide fine particles (CI Chemical, primary particle diameter 12 nm) was changed to 0.15 part.

(Carrier Production Comparative Example 1)
Carrier F 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 the resin of Synthesis Example 4.

(Carrier Production Comparative Example 2)
With respect to the resin obtained in Resin Synthesis Example 4, isophorone diisocyanate / trimethylolpropane adduct (IPDI / TMP system: NCO% = 6.1%) was used as a crosslinking agent in an OH / NCO molar ratio (OH is Synthesis Example 10). OH in resin) 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 160 ° C./1 hour to obtain carrier G.

(Carrier Production Comparative Example 3)
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 H was obtained.

(Carrier Production Comparative Example 4)
Carrier I corresponding to Carrier Production Comparative Example 4 was obtained in exactly the same manner as in Carrier Production Example 1 except that 0.05 part of cerium oxide fine particles (Cai Kasei Co., Ltd., primary particle diameter 12 nm) was changed to 0.01 part.

(Carrier Production Comparative Example 5)
Carrier J corresponding to Carrier Production Comparative Example 5 was obtained in exactly the same manner as in Carrier Production Example 1 except that 0.05 part of cerium oxide fine particles (Cai Kasei Co., Ltd., primary particle diameter: 12 nm) was changed to 0.18 part.

[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 filled in a cell composed of a fluororesin container 2 in which electrodes (1a) and (1b) having a surface area of 2.5 cm × 4 cm are accommodated at a distance of 0.2 cm. 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). Formula (1)

から、体積固有抵抗［Ωｃｍ］を算出した。

From this, 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.

[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 particles 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 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 J (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 J 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 comparative examples and the toner 1 of the examples, the image area ratio is 0.5%, and the initial and after 100,000 sheets and 300,000 sheets of running. The volume resistivity was measured, and the amount of change in volume resistivity was calculated.
The initial volume resistivity (LogR1) of the carrier is a common logarithmic value of the volume resistivity of the carrier measured in the same manner as the above [Volume resistivity]. The carrier specific volume resistance (LogR2) after running 10K sheets and the volume specific resistance (LogR3) of carrier after running 30K sheets use a carrier from which the toner of each color in the developer after running is removed using a blow-off device. The measurement was carried out in the same manner as described above except that. The target value of the volume resistivity is 1.5 [Log (Ωcm)] or less in absolute value.
In addition, image evaluation was performed using the obtained developer 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 comparative examples and the toner 1 of the examples, the charge amount of the carrier after the initial and 100,000 sheets of running with an image area ratio of 20% is determined. Measurements were made to calculate the amount of charge reduction.
The initial carrier charge amount (Q1) was determined by mixing a carrier A to H and the toner 1 of the example at a mass ratio of 93: 7 and triboelectrically charging 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.
The developer evaluation results are shown in Tables 2 and 3.

(Figure 1)
1a Electrode 1b Electrode 2 Fluororesin 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 (16)

A carrier for an electrostatic latent image developer comprising magnetic core material particles and a resin layer covering the surface thereof, wherein the resin layer comprises at least part A represented by the following general formula (1) and the following general An electrostatic latent image characterized by containing a resin obtained by heat-treating a copolymer containing a B moiety represented by formula (2) and containing conductive fine particles made of cerium oxide. Carrier for image developer.

(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 (3).

(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 electrostatic latent image developer according to claim 1, wherein the conductive fine particles contained in the coating layer have a coverage of 10 to 80% with respect to a carrier core material. Career.   The resin material layer of the said copolymer containing the said cerium oxide electroconductive particle was coat | covered with the said core material particle | grain, and it heat-processed after that, and was obtained in any one of Claim 1 thru | or 3 characterized by the above-mentioned. Carrier for electrostatic latent image developer. The carrier for an electrostatic latent image developer according to any one of claims 1 to 4, wherein a heat treatment temperature during the heat treatment is 100 to 350 ° C. 6. The electrostatic latent image developer carrier according to claim 1, wherein the volume resistivity is 1 × 10 ⁸ Ω · cm or more and 1 × 10 ¹⁷ Ω · cm or less.   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.   The electrostatic latent image developer carrier according to claim 1, wherein the core material particles have a weight average particle diameter of 20 μm to 65 μm. 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 10, wherein the toner is a color toner.   A method for producing a carrier, comprising a step of forming a core material particle having magnetism and a coating layer covering the surface of the core material particle, wherein the resin layer includes at least an A portion represented by the general formula (1) Production of a carrier comprising a resin obtained by heat-treating a copolymer containing a B moiety represented by formula (2), comprising conductive fine particles comprising cerium oxide Method.   A developer-containing container comprising the developer according to claim 10. Forming an electrostatic latent image on the electrostatic latent image carrier;
A step of developing the electrostatic latent image formed on the electrostatic latent image carrier using the developer according to claim 10 or 11 to form a toner image;
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.   The electrostatic latent image carrier and the means for developing the electrostatic latent image formed on the electrostatic latent image carrier using the developer according to claim 10 or 11 are supported at least integrally. Process cartridge characterized by. A replenishment developer containing 2 to 50 parts by weight of toner with respect to 1 part by weight of the carrier, wherein the carrier is the carrier according to any one of claims 1 to 9. Replenishment developer

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