JP2010217629A - Electrophotographic carrier, electrophotographic two-component developer and image forming method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a carrier which has a uniform coating layer with a desired low resistance value formed on a surface of a carrier core material, and which suppresses toner spent, film shaving of the carrier coating layer and color staining with a toner caused thereby, even in long-time agitation. <P>SOLUTION: The photographic carrier is made by coating the surface of a core material particle made of a magnetic material with the coating layer containing at least a binder resin and conductive particulates. The binder resin has a segment (A) containing one or two or more kinds of polymerizable vinyl monomer as a structure unit, and a segment (B) containing a partial cleavage structure of cage silsesquioxane as a structure unit, and the conductive particulates are phosphorus-doped conductive tin oxide particulates composed of free particles of tin oxide doped with phosphorus. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a carrier for developing an electrostatic latent image for a two-component developer used for image formation in an electrostatic copying process such as a copying machine, a facsimile machine, and a printer, a developer using the carrier, and an image forming method. .

  Conventionally, dry development methods used in electrophotographic copying machines and the like are two-component development methods in which development is performed using a two-component developer comprising a carrier for developing an electrostatic latent image having magnetic properties and toner, and toner only. There is known a one-component development system in which development is carried out using a toner.

  In the two-component developing system, a two-component developing apparatus having a developing sleeve that is a cylindrical developer carrying member that is normally provided with a magnet roller composed of a magnet body having a plurality of magnetic poles therein and is rotatably supported. Is used. While carrying a carrier for developing an electrostatic latent image with toner attached to the surface of the developing sleeve, it is transported to a developing area opposite to the image carrier and developed with a magnetic brush made of a two-component developer. Is. As described above, in the two-component development system, charging is performed by stirring and mixing the carrier for developing an electrostatic latent image and the toner, so that the chargeability of the toner is stable, and a relatively stable good image can be obtained. It is done.

  The two-component developer is repeatedly used while replenishing toner consumed by development. For this reason, with respect to the carrier, the toner component is prevented from being spent on the carrier surface, the formation of a uniform surface of the carrier, the surface oxidation is prevented, the moisture sensitivity is prevented, the life of the developer is extended, the carrier is prevented from adhering to the photoreceptor surface, For the purpose of protecting the body from scratches or abrasion by the carrier, controlling the charge polarity, or adjusting the charge amount, the carrier core is usually coated with a suitable resin material to provide a hard and high-strength coating. A layer is provided.

  However, durability and carrier adhesion suppression are still insufficient, and especially regarding durability, the spent on the carrier surface of the toner and the resulting unstable charge amount, and the reduction of the coating layer due to film scraping of the coating resin and Along with this, there is a problem such as a decrease in resistance and color stains due to the detachment of additive components, and a good image can be obtained initially, but as the number of copies increases, the image quality of the copied image decreases, Need to improve.

  In particular, it has been attempted to prevent the spent on the carrier surface of the toner by using a resin having a low surface energy such as a silicone resin. It also reduces the adhesion to. In addition, a general silicone resin has a small cohesive force acting between molecules, and cannot be said to have a sufficient film strength. For this reason, although toner spent on the carrier surface is suppressed, peeling of the carrier coating layer (silicone resin) from the core material particles is promoted, causing a decrease in resistance due to the core material exposure.

  For these problems, Patent Document 1 discloses that the coating layer contains an acrylic resin and a silicone resin, and has a low surface energy so as to further cover the acrylic resin portion having high adhesion to the core material. It has been proposed to provide a carrier having a two-layer structure covered with a silicone resin. Furthermore, in Patent Documents 2 and 3, by using an acrylic-modified silicone resin as having both good characteristics of the acrylic resin and the silicone resin, carrier chargeability, core material adhesion, and resistance Improvement of spent is proposed. This method achieves both the purpose of improving the adhesion between the core material and the coating resin, preventing the deterioration of the image quality of the developed image due to the peeling of the coating layer, and preventing the image quality deterioration due to the toner spent. However, in this method, deterioration of the coating layer due to stress during stirring of the developer, for example, film abrasion due to insufficient mechanical strength of the coating layer easily occurs, and there is room for improvement in the durability of the carrier. In general, a silicone resin has a small cohesive force acting between molecules, and the film strength is not sufficient. In other words, the siloxane bond (Si-O) has about 50% ionic bondability compared to the carbon bond (CC) made of 100% covalent bond, and the presence of this ionic bond is a methyl group bonded to the Si atom. It strengthens CH bonds and makes it less susceptible to attack by other molecules and exhibits water repellency (repellency), but at the same time, it reduces the adhesion to carrier core particles. On the other hand, the siloxane (Si-O) bond of the silicon resin has a long distance between bonds and a low electron density, so that the rotation of the bond is easy (the siloxane conclusion is more flexible) and flexible. Further, in the case of a typical dimethylpolysiloxane chain, two methyl groups are bonded and are bulky and vibrate with a relatively large amplitude, so that adjacent molecules are difficult to approach. Therefore, a simple blend of such a silicone resin and another resin, or a bond between the ends of the siloxane chain of the silicone resin and the end of the molecular chain of another polymer material (stretch polymerization) alone, toughness ( It is difficult to achieve a strong bond between the flexibility and flexibility) and the hardness and the surface of the carrier core material.

  On the other hand, in recent years, there is an increasing demand for higher image quality and longer life, and carrier resistance adjustment is one of the important issues in achieving them. Conventionally, in a monochrome machine, conductive carbon black has been used as a carrier resistance adjusting agent. However, carbon black provides low resistance, but when the coating layer is peeled off or abraded due to agitation stress, the black component derived from carbon is mixed into the toner. On the other hand, color stains occur, which is a big problem.

  On the other hand, in patent documents 4-5, it coat | covered by using the conductive metal oxide fine particle in which the conductive layer which consists of a tin oxide and an indium oxide was formed in the surface using white metal oxide fine particle as a base particle. Both the resistance adjustment of the layer and the suppression of color stains are achieved. Further, in Patent Document 6, a conductive layer having a thickness of 5 to 50 mm made of tin oxide in which two or more kinds of white metal oxide fine particles having different average particle diameters are used as base particles and a group V metal is dissolved on the surface thereof is used. Similarly, by using the conductive metal oxide fine particles formed with the coating, both the resistance adjustment of the coating layer and the suppression of color stains are achieved. In this method, since white particles are used, a remarkable effect is exhibited with respect to color stains. On the other hand, for the resistance adjustment, only a thin conductive layer is formed on the surface of the high resistivity metal oxide fine particles, and in order to adjust the resistance of the coating layer to a desired low value, an excessive amount of fine particles. Must be included. For this reason, deterioration in spent resistance due to a decrease in the resin component in the coating layer, reduction in strength of the coating layer due to localization of the fine particles, and further, the conductive layer of the fine particles is worn and resisted by agitation stress over time. There is a problem of rising.

  On the other hand, in Patent Document 7, by adding a certain amount of antimony containing tin oxide and a certain amount of NaB2BO as a sodium component, the resistance value of the coating layer is adjusted low, and the whiteness is improved. The dispersibility of fine particles is improved. The effect of this method is remarkable compared with the conventional method, but it cannot be said that it is sufficient for the recent strong demand for speeding up and long life, and further improvement is desired. . In addition, antimony has been concerned about safety, and in this respect also needs to be improved.

  In this way, means that can simultaneously satisfy the items such as reduction of film abrasion of the coating layer, suppression of toner spent on the carrier surface, furthermore, resistance adjustment of the coating layer and prevention of toner color stains are presented. There is no need for further improvement.

  An object of the present invention is to solve various problems in the prior art and achieve the following objects. That is, the present invention forms a uniform coating layer having a desired low resistance value on the surface of the carrier core material, and also removes the toner spent and the carrier coating layer from being scraped and the resulting toner color stains even during long-term stirring. An object is to provide a carrier that can be suppressed, a developer using the carrier, and an image forming method.

  As a result of intensive studies in view of the above problems, the present inventors have obtained the following knowledge. That is, a binder resin having a segment containing one or more polymerizable vinyl monomers as a structural unit, and a segment containing a partial cleavage structure of a cage silsesquioxane having a specific structure as a structural unit; It has been found that the above problem can be effectively achieved by forming a coating layer containing at least phosphorus-doped conductive tin oxide fine particles composed of single particles of tin oxide doped with phosphorus on the surface of the core material particles.

The present invention is based on the above findings by the present inventors, and means for solving the above problems are as follows. That is,
<1> A carrier obtained by coating the surface of core particles made of a magnetic material with a coating layer containing at least a binder resin and conductive fine particles, wherein the binder resin is one or more polymerizable vinyl monomers. (A), a partially-cleavage structure of a cage silsesquioxane represented by the following general formula (1), and / or a cage silsesqui represented by the following general formula (2) A segment (B) containing a partial cleavage structure of oxan as a structural unit, and the conductive fine particles are phosphorus-doped conductive tin oxide fine particles composed of single particles of tin oxide doped with phosphorus Is a carrier for electrophotography.

（但し、ｎは４以上の整数を表し、置換基Ｒは、水素原子、ハロゲン原子、炭素数１〜１０のアルコキシ基またはアリロキシ基、炭素数１〜２０の飽和炭化水素基、炭素数２〜２０のアルケニル基、炭素数６〜２０のアラルキル基、炭素数７〜２０のアリール基、及びケイ素数１〜１０のケイ素原子含有基のうちいずれかを表す。）

(However, n represents an integer of 4 or more, and the substituent R is a hydrogen atom, a halogen atom, an alkoxy group having 1 to 10 carbon atoms or an allyloxy group, a saturated hydrocarbon group having 1 to 20 carbon atoms, or 2 to 2 carbon atoms. It represents any of 20 alkenyl groups, 6 to 20 carbon atoms aralkyl groups, 7 to 20 carbon atoms aryl groups, and 1 to 10 silicon atom-containing groups.)

（但し、ｎ及びｍはそれぞれ２以上の整数を表し、置換基Ｒ１、Ｒ２は、それぞれ独立に、水素原子、ハロゲン原子、炭素数１〜１０のアルコキシ基またはアリロキシ基、炭素数１〜２０の飽和炭化水素基、炭素数２〜２０のアルケニル基、炭素数６〜２０のアラルキル基、炭素数７〜２０のアリール基、及びケイ素数１〜１０のケイ素原子含有基のうちいずれかを表す。）
＜２＞ 前記結着樹脂は、ＧＰＣ（ゲルパーミエーションクロマトグラフィー）を用いて求めたスチレン換算分子量分布から算出される多分散度が３．０以下であることを特徴とする前記＜１＞に記載の電子写真用キャリアである。
＜３＞ 前記結着樹脂は、質量平均分子量Ｍｗが２０，０００〜２００，０００の範囲にあることを特徴とする前記＜１＞または＜２＞のいずれかに記載の電子写真用キャリアである。
＜４＞ 前記セグメント（Ａ）は、少なくともヒドロキシル基を有する一種又は二種以上の重合性ビニルモノマーの共重合体を含むことを特徴とする前記＜１＞乃至＜３＞のいずれかに記載の電子写真用キャリアである。
＜５＞ 前記セグメント（Ａ）は、アクリル樹脂のセグメントを有し、前記アクリル樹脂のセグメントがアミノ樹脂乃至イソシアネートによって架橋されていることを特徴とする前記＜１＞乃至＜４＞のいずれかに記載の電子写真用キャリアである。
＜６＞ 前記結着樹脂は、前記セグメント（Ｂ）を重合開始物質とするリビングラジカル重合によって、前記セグメント（Ａ）が形成されたことを特徴とする前記＜１＞乃至＜５＞のいずれかに記載の電子写真用キャリアである。
＜７＞ 前記セグメント（Ａ）は、原子移動ラジカル重合法によって重合性ビニルモノマーが重合したことを特徴とする前記＜１＞乃至＜６＞のいずれかに記載の電子写真用キャリアである。
＜８＞ 前記被覆層に無機微粒子を含有し、該無機微粒子の体積平均粒子径が１００ｎｍ以上１μｍ以下であることを特徴とする前記＜１＞乃至＜７＞のいずれかに記載の電子写真用キャリアである。
＜９＞ 前記被覆層は、アミノシランカップリング剤をさらに含むことを特徴とする前記＜１＞乃至＜８＞のいずれかに記載の電子写真用キャリアである。
＜１０＞ 前記電子写真用キャリアに１０００Ｖの直流電圧を印加したときの体積抵抗率が１０［ｌｏｇ（Ω・ｃｍ）］以上１６［ｌｏｇ（Ω・ｃｍ）］以下であることを特徴とする前記＜１＞乃至＜９＞のいずれかに記載の電子写真用キャリアである。
＜１１＞ 前記電子写真用キャリアの体積平均粒径が２０μｍ以上６５μｍ以下であることを特徴とする前記＜１＞乃至＜１０＞のいずれかに記載の電子写真用キャリアである。
＜１２＞ 前記＜１＞乃至＜１１＞のいずれかに記載の電子写真用キャリアと、トナーとからなることを特徴とする電子写真用二成分現像剤である。
＜１３＞ 静電潜像担持体上に静電潜像を形成する静電潜像形成工程と、前記静電潜像を前記＜１２＞に記載の現像剤を用いて現像して可視像を形成する現像工程と、前記可視像を記録媒体に転写する転写工程と、前記記録媒体に転写された転写像を定着させる定着工程とを少なくとも含むことを特徴とする画像形成方法である。

(However, n and m represent an integer greater than or equal to 2, respectively, and substituent R1, R2 is respectively independently a hydrogen atom, a halogen atom, a C1-C10 alkoxy group, or an allyloxy group, C1-C20. It represents any of a saturated hydrocarbon group, an alkenyl group having 2 to 20 carbon atoms, an aralkyl group having 6 to 20 carbon atoms, an aryl group having 7 to 20 carbon atoms, and a silicon atom-containing group having 1 to 10 silicon atoms. )
<2> The binder resin according to <1>, wherein the binder resin has a polydispersity of 3.0 or less calculated from a styrene-converted molecular weight distribution obtained by using GPC (gel permeation chromatography). The carrier for electrophotography described.
<3> The electrophotographic carrier according to either <1> or <2>, wherein the binder resin has a mass average molecular weight Mw in the range of 20,000 to 200,000. .
<4> The segment (A) includes a copolymer of one or two or more polymerizable vinyl monomers having at least a hydroxyl group, according to any one of the items <1> to <3>, It is a carrier for electrophotography.
<5> The segment (A) includes an acrylic resin segment, and the acrylic resin segment is crosslinked with an amino resin or an isocyanate, according to any one of the above items <1> to <4> The carrier for electrophotography described.
<6> The binder resin according to any one of <1> to <5>, wherein the segment (A) is formed by living radical polymerization using the segment (B) as a polymerization initiator. The carrier for electrophotography described in 1.
<7> The electrophotographic carrier according to any one of <1> to <6>, wherein the segment (A) is a polymerizable vinyl monomer polymerized by an atom transfer radical polymerization method.
<8> The electrophotographic film according to any one of <1> to <7>, wherein the coating layer contains inorganic fine particles, and the volume average particle diameter of the inorganic fine particles is from 100 nm to 1 μm. Is a career.
<9> The electrophotographic carrier according to any one of <1> to <8>, wherein the coating layer further includes an aminosilane coupling agent.
<10> The volume resistivity when a DC voltage of 1000 V is applied to the electrophotographic carrier is 10 [log (Ω · cm)] or more and 16 [log (Ω · cm)] or less, <1> to <9> The electrophotographic carrier according to any one of <9>.
<11> The electrophotographic carrier according to any one of <1> to <10>, wherein the electrophotographic carrier has a volume average particle diameter of 20 μm to 65 μm.
<12> An electrophotographic two-component developer comprising the electrophotographic carrier according to any one of <1> to <11> and a toner.
<13> An electrostatic latent image forming step of forming an electrostatic latent image on the electrostatic latent image carrier, and developing the electrostatic latent image using the developer described in <12> to form a visible image The image forming method includes at least a developing step for forming the image, a transfer step for transferring the visible image to a recording medium, and a fixing step for fixing the transferred image transferred to the recording medium.

  According to the present invention, in an electrophotographic carrier, a segment containing one or more polymerizable vinyl monomers as a structural unit, and a partial cleavage structure of a cage silsesquioxane having a specific structure as a structural unit A coating layer containing at least a binder resin having a segment containing and a phosphorus-doped conductive tin oxide fine particle composed of simple particles of tin oxide doped with phosphorus on the surface of the core particle, Has a desired resistance value, a carrier that can maintain good image quality by suppressing toner spent and film layer scraping even in long-term use, toner color stains, a developer using the carrier, and An image forming method is provided.

An example of a powder volume low-efficiency measuring apparatus particularly suitable for measuring the volume low-efficiency of the carrier of the present invention will be shown. 1 is an example of an image forming apparatus suitable for performing the image forming method of the present invention. It is another example of an image forming apparatus suitable for performing the image forming method of the present invention. It is still another example of an image forming apparatus suitable for performing the image forming method of the present invention.

  The materials constituting the electrophotographic carrier of the present invention will be described. Note that it is easy for a person skilled in the art to change or modify the present invention within the scope of the claims to form other embodiments, and these changes and modifications are included in the scope of the claims, The following description is an example of the best mode of the present invention, and does not limit the scope of the claims.

(Career)
The carrier of the present invention is represented by the general formula (1), the surface of core particles (core material) made of a magnetic material, the segment (A) containing at least one or two or more polymerizable vinyl monomers as structural units. And a segment (B) containing as a structural unit a partial cleavage structure of a cage-type silsesquioxane and / or a partial cleavage structure of a cage-type silsesquioxane represented by the general formula (2) It is a carrier coated with a coating layer containing a binder resin and phosphorus-doped conductive tin oxide fine particles composed of single particles of tin oxide doped with phosphorus.

―Carrier core material―
The core material is not particularly limited as long as it has magnetic particles, and examples thereof include ferrite, magnetite, iron, nickel and the like. Further, when considering adaptability to environmental aspects that have been remarkably advanced in recent years, if it is a ferrite, it is not a conventional copper-zinc ferrite, but, for example, manganese ferrite, manganese-magnesium ferrite, manganese-strontium ferrite, manganese- It is preferable to use magnesium-strontium ferrite, lithium ferrite, or the like.

  In addition, for the purpose of controlling the resistance of the core material, for the purpose of increasing the production stability, etc., other elements such as Li, Na, K, Ca, Ba, Y, Ti, Zr, One or more elements such as V, Ag, Ni, Cu, Zn, Al, Sn, Sb, and Bi may be blended. As these compounding quantities, it is preferable that it is 5 atomic% or less of the total amount of metal elements, and it is more preferable that it is 3 atomic% or less.

―Coating layer―
The coating layer contains at least a binder resin and conductive fine particles, and may contain other components such as inorganic fine particles as necessary.

[Binder resin]
As described above, the binder resin includes a segment (A) containing at least one or two or more polymerizable vinyl monomers in a structural unit, a cage silsesquioxane partial cleavage structure, and / or a cage sil It has the segment (B) which contains a sesquioxane partial cleavage structure in a structural unit.

<Segment (A)>
The polymerizable vinyl monomer constituting the segment (A) is not particularly limited as long as it is a polymerizable vinyl monomer, and can be appropriately selected according to the purpose. Examples of the polymerizable vinyl monomer include methyl acrylate, ethyl acrylate, butyl acrylate, isobutyl acrylate, 2-ethylhexyl acrylate, heptyl acrylate, dodecyl acrylate, 2-hydroxyethyl acrylate, 3-acrylic acid 3- Acrylic acid esters such as chloro-2-hydroxypropyl, diethylene glycol monoacrylic acid ester, glycerin monoacrylic acid ester, N-methylolacrylamide; methyl methacrylate, ethyl methacrylate, sec-butyl methacrylate, tert-butyl methacrylate, methacrylic acid Cyclohexyl acid, dodecyl methacrylate, 2-ethylhexyl methacrylate, 2-hydroxyethyl methacrylate, 3-chloro-2-hydroxypropyl methacrylate, diethylene glycol Methacrylic acid esters, glycerol monomethacrylate, methacrylic acid esters such as N- methylol methacrylamide, acrylic acid, methacrylic acid, itaconic acid, crotonic acid, fumaric acid, maleic acid, and maleic anhydride. These polymerizable vinyl monomers may form the segment (A) in the form of a homopolymer or a copolymer.

  By forming the segment (A) with a polymerizable vinyl monomer, particularly an acrylic resin skeleton, the adhesion between the core material and the fine particles contained in the coating layer can be strengthened. Therefore, it is possible to stably maintain the coating layer without giving deterioration such as film scraping or film peeling of the coating layer. Further, the acrylic resin skeleton can firmly hold particles contained in the coating layer such as a core material and conductive particles due to strong adhesiveness. In particular, an acrylic resin skeleton is preferable because it can exert a strong effect in holding fine particles having a particle size larger than the thickness of the coating layer.

  The segment (A) can be further crosslinked by an amino resin or an isocyanate compound to prevent fusion between resins that tend to occur when an acrylic resin is used alone, while maintaining appropriate elasticity, so-called blocking. it can. At this time, the segment (A) may introduce a hydroxyl group, which is a crosslinking point with the amino resin, into the segment (A) skeleton by copolymerizing one or more polymerizable vinyl monomers having a hydroxyl group. I can do it.

  The amino resin is not particularly limited and can be appropriately selected from conventionally known amino resins according to the purpose. Among them, guanamine resin and melamine resin also improve the charge imparting ability of the carrier. This is particularly preferable. Further, when it is necessary to appropriately control the charge imparting ability of the carrier, at least one of guanamine resin and melamine resin may be used in combination with another amino resin.

  Examples of the isocyanate compound include tolylene diisocyanate, diphenylmethane diisocyanate, triphenylmethane triisocyanate, polyphenylmethane polyisocyanate, modified diphenylmethane diisocyanate (modified MDI), hydrogenated xylylene diisocyanate (H-XDI), xylylene diisocyanate ( XDI), hexamethylene diisocyanate (HMDI), trimethylhexamethylene diisocyanate (TMHMDI), tetramethylxylylene diisocyanate (m-TMXDI), isophorone diisocyanate (IPDI), norbornene diisocyanate (NBDI), 1,3-bis (isocyanatomethyl) ) Polyisocyanate such as cyclohexane (H6XDI), 1,5-naphthalene diisocyanate Sulfonates, or trimer compounds of these polyisocyanates, reaction products of these polyisocyanates with polyols. These isocyanate compounds may be used singly or in combination of two or more, and further, blocked isocyanates in which part or all of the isocyanate groups are blocked using a known blocking agent such as a phenol compound or oxime. Kinds may be used.

<Segment (B)>
The segment (B), which is a constituent element of the binder resin, is represented by the partial cleavage structure of a cage silsesquioxane represented by the following general formula (1) and / or the following general formula (2). It has a partial cleavage structure of cage-type silsesquioxane.

但し、ｎは４以上の整数を表し、置換基Ｒは、水素原子、ハロゲン原子、炭素数１〜１０のアルコキシ基またはアリロキシ基、炭素数１〜２０の飽和炭化水素基、炭素数２〜２０のアルケニル基、炭素数６〜２０のアラルキル基、炭素数７〜２０のアリール基、及びケイ素数１〜１０のケイ素原子含有基のうちいずれかを表す。Ｒのうち少なくとも１つ以上はアルコキシ基であることが好ましい。

However, n represents an integer greater than or equal to 4, and the substituent R is a hydrogen atom, a halogen atom, a C1-C10 alkoxy group or an allyloxy group, a C1-C20 saturated hydrocarbon group, C2-C20. Or an aralkyl group having 6 to 20 carbon atoms, an aryl group having 7 to 20 carbon atoms, or a silicon atom-containing group having 1 to 10 silicon atoms. At least one of R is preferably an alkoxy group.

但し、ｎ及びｍはそれぞれ２以上の整数を表し、置換基Ｒ１、Ｒ２は、それぞれ独立に、水素原子、ハロゲン原子、炭素数１〜１０のアルコキシ基またはアリロキシ基、炭素数１〜２０の飽和炭化水素基、炭素数２〜２０のアルケニル基、炭素数６〜２０のアラルキル基、炭素数７〜２０のアリール基、及びケイ素数１〜１０のケイ素原子含有基のうちいずれかを表す。Ｒ１、Ｒ２のうち少なくとも１つ以上はアルコキシ基であることが好ましい。

However, n and m each represent an integer of 2 or more, and the substituents R1 and R2 are each independently a hydrogen atom, a halogen atom, an alkoxy group having 1 to 10 carbon atoms or an allyloxy group, and a saturated group having 1 to 20 carbon atoms. It represents any one of a hydrocarbon group, an alkenyl group having 2 to 20 carbon atoms, an aralkyl group having 6 to 20 carbon atoms, an aryl group having 7 to 20 carbon atoms, and a silicon atom-containing group having 1 to 10 silicon atoms. At least one of R1 and R2 is preferably an alkoxy group.

  The term “silsesquioxane” in the cage silsesquioxane generally refers to sesqui (meaning 3/2), so-called (RSiO3 / 2), and so-called three organic substituents on the Si atom. It means a polysiloxane compound composed of T unit siloxane. As silsesquioxane as a structural unit, amorphous, ladder-type, cage-type, or partial cleavage structures thereof are known. The cage silsesquioxane compound can be synthesized, for example, by the method described in JP-A No. 2004-143449. The cage silsesquioxane compound includes cage silsesquioxane or a derivative thereof.

  As will be described later, the cage silsesquioxane compound has a functional group capable of reacting with at least one of a binder resin and a monomer which is a constituent unit of the binder resin. The sesquioxane compound and the binder resin and at least one of the monomer units constituting the binder resin are chemically bonded.

<Combination of segment (A) and segment (B)>
As a method for forming a chemical bond between an acrylic resin material and a silsesquioxane compound having a cage structure, at least, for example, the general formula (1) and / or the general formula (2) is used. Method of forming a polymer chain by polymerizing an acrylic monomer from the partial cleavage structure (activated oxygen atom group at the partial cleavage end) of the cage-type silsesquioxane compound as a polymerization initiator Is mentioned. By this polymerization method, a vinyl polymer skeleton and a silsesquioxane having a cage structure can be chemically bonded firmly to form a binder resin having a desired strength. By such a reaction, the segment (A) and the segment (B) form a binder resin in a chemically bonded state, and a coating layer having excellent wear resistance and spent resistance is formed.
Furthermore, the partially-cleavage structure of the cage silsesquioxane compound represented by the general formula (1) and / or the general formula (2) is a radical polymerizable double bond (segment (A) is clear from the definition) A hydrolyzable alkoxy group as a precursor of a silanol (SiOH) group, which is well known to be added to such a radically polymerizable group), and can contain the same halogen atom. The polymerizable double bond site and the polymerizable alkenyl group may also be included, but these functional groups also contribute to a close bond between the segment (A) and the segment (B) (provided that the SiH group hydrogen radicals in a high temperature, quite vigorously attack the unsaturated bond of an acrylate monomer (CH ₂ = CH) (in other words, inhibits the polymerizability of the vinyl group) is. of In addition, the silanol (SiOH) group generated in the cage-type silsesquioxane compound represented by the general formula (1) and / or the general formula (2) is self-condensed (by dehydration condensation between silsesquioxane compound molecules). Siloxane bond formation) and the hydroxyl group of the segment (A), and can also bind to amino resins and isocyanates that can be added as a cross-linking agent. In this way, the coupling reaction between the segment (A) and the segment (B) is miscellaneous, and in addition to this, the crosslinking reaction between the segments (A) and the crosslinking between the segments (B) Since the reaction, bonding between the segments (A) and (B) through the cross-linking agent may occur, it is considered that a strong and tough coating can be obtained.

<Polydispersity of binder resin, molecular weight>
The binder resin preferably has a polydispersity of 3.0 or less calculated from a styrene-converted molecular weight distribution determined using GPC (gel permeation chromatography). The polydispersity is an index representing the degree of molecular weight distribution of the binder resin, and when the polydispersity is larger than 3.0, the molecular weight distribution becomes too wide, and the high molecular weight component and the low molecular weight component increase. The above-mentioned problems may be caused in combination, which is not preferable.

  Furthermore, the mass average molecular weight Mw of the binder resin is preferably in the range of 20,000 to 200,000. When the weight average molecular weight Mw is less than 20,000, the strength of the coating layer cannot be maintained sufficiently, the abrasion resistance is deteriorated, and the toner component in the developer is fused on the carrier coating layer. May become noticeable. Furthermore, when Mw exceeds 200,000, the viscosity of the resin solution increases when the core material is coated with the resin solution, and it may be difficult to coat uniformly.

<Living radical polymerization method>
The method for forming the binder resin having such molecular weight and polydispersity is not particularly limited, but a living radical polymerization method in which the segment (A) is polymerized using the segment (B) as a polymerization initiator is preferable. . The living radical polymerization method is a radical polymerization that is maintained without losing the activity of the polymerization reaction at the terminal of the reactant. For example, a cobalt porphyrin complex disclosed in Non-Patent Document 1 is used. Examples using the radical capping agent of a nitroxide compound disclosed in Non-Patent Document 2, examples of using a radical capping agent disclosed in Non-Patent Document 2, using an organic halogen compound disclosed in Patent Documents 8 and 9 as an initiator, and using a transition metal complex as a catalyst Examples thereof include a so-called atom transfer radical polymerization (ATRP) method in which a polymerization reaction is performed.

  These living radical polymerization methods introduce monomers with specific functional groups into controlled positions such as polymer chain ends compared to conventional free radical polymerization methods in which a plurality of monomers are simply copolymerized. There is an advantage that can be. In the carrier of the present invention, it is particularly preferable to form a binder resin using an atom transfer radical polymerization method among the living radical polymerization methods. As described in Non-Patent Document 3, this atom transfer radical polymerization method is a monomer capable of radical polymerization such as an acrylic monomer and a styrene monomer in the presence of a metal salt and an amine compound, for example, an α-haloester group as an initiating group. It is a polymerization method that grows. By using this polymerization method, it is possible to easily control the molecular weight, molecular weight distribution (polydispersity), block copolymerization, and the like of the organic polymer.

  In the living radical polymerization method, inactivation during polymerization is difficult to occur, a polymer having a narrow molecular weight distribution (low polydispersity) can be obtained, and the molecular weight can be freely controlled by the ratio of the monomer and the initiator. The point is a feature. By using the living radical polymerization method as a method for forming the binder resin used in the present invention, the molecular weight distribution is narrowed, the viscosity of the coating layer liquid is low, and the molecular weight and the position and amount of the constituent monomers can be controlled. An optimum binder resin can be provided as the coating layer of the carrier of the present invention. The conventional radical polymerization method is free radical polymerization, and only a polymer having a wide molecular weight distribution and a high polydispersity and a high viscosity can be obtained, and a monomer having a desired functional group is a probability. Therefore, it is difficult to obtain a copolymer at a desired ratio because it is only introduced into the polymer.

<Phosphorus-doped conductive tin oxide fine particles>
In the present invention, the coating layer contains phosphorus-doped conductive tin oxide fine particles composed of single particles of tin oxide doped with phosphorus.
Tin oxide exhibits conductivity by doping with antimony, fluorine, or a Group V metal such as phosphorus. Among them, antimony-doped conductive tin oxide (ATO) doped with antimony is well known, but although ATO is excellent in conductivity, the coloring property (blue black) attributed to antimony is very strong, so the coating layer This is not preferable because the whiteness of the toner is remarkably deteriorated.

  In the present invention, the phosphorus-doped conductive tin oxide fine particles contained in the coating layer are doped with phosphorus in tin oxide, and are excellent in conductivity and low in colorability, and thus form a coating layer with low resistance and low colorability. be able to. Further, by doping with phosphorus, the dispersion stability of the fine particles in the coating layer is also improved, so that a decrease in strength of the coating layer due to aggregation of the fine particles can be suppressed.

As the doping amount of phosphorus (P) with respect to tin oxide (SnO2) in the phosphorus-doped conductive tin oxide fine particles, the molar ratio of phosphorus / tin oxide is preferably 0.005 to 0.2.
When the phosphorus / tin oxide molar ratio is less than 0.005, the conductivity of the phosphorus-doped conductive tin oxide fine particles may not be sufficiently high, and the resistance of the coating layer may not be adjusted to a desired value. Absent. On the other hand, if it exceeds 0.2, the color of the phosphorus-doped conductive tin oxide fine particles becomes deep and the whiteness of the coating layer may be deteriorated, which is not preferable.

  Further, the phosphorus-doped conductive tin oxide fine particles are different from coated conductive fine particles in which fine particles such as metal oxide are used as base particles and a thin conductive layer is formed on the surface of the fine particles. Since it consists of a single particle, the volume resistivity of the coating layer can be adjusted to a desired low value with a smaller addition amount than the coated conductive fine particles. Thereby, the strength reduction by the ratio of the binder resin in a coating layer falling is suppressed.

The content of the phosphorus-doped conductive tin oxide fine particles depends on the conductivity of the phosphorus-doped conductive tin oxide fine particles, the film thickness of the coating layer, the desired resistance value of the coating layer, etc. The range of mass% to 50 mass% is preferable, and the range of 15 mass% to 40 mass% is more preferable.
When the content is less than 10% by mass, the resistance of the coating layer may not be adjusted to a desired value, and when it is more than 50% by mass, other physical properties of the coating layer may be affected. Therefore, it is not preferable.

The volume average particle diameter of the phosphorus-doped conductive tin oxide fine particles is preferably 10 nm to 300 nm, and more preferably 10 nm to 150 nm.
In addition, the volume average particle diameter of the phosphorus-doped conductive tin oxide fine particles can be measured using, for example, a laser Doppler / dynamic light scattering particle size distribution apparatus.

<Aminosilane coupling agent>
If necessary, the coating layer solution may further contain an aminosilane coupling agent. By containing the aminosilane coupling agent, the charge amount of the carrier with respect to the toner can be well controlled. As the aminosilane coupling agent, for example, those represented by the structural formula shown in the following chemical formula (3) are suitable.

  The content of the aminosilane coupling agent is preferably 0.001% by mass to 30% by mass of the entire coating layer, and more preferably 0.001% by mass to 10% by mass. When the content is less than 0.001% by mass, the chargeability is likely to be affected by the environment, and the product yield tends to decrease. When the content exceeds 30% by mass, the coating layer tends to be brittle. The wear resistance of the coating layer may be reduced.

<Inorganic fine particles>
In the present invention, the coating layer preferably further contains inorganic fine particles having a volume average particle diameter of 100 nm to 1 μm. As a result, the coating layer can be significantly prevented from being scraped or peeled off due to a long-term stirring stress.
When the volume average particle size of the inorganic fine particles is larger than 1 μm, the inorganic fine particles are too large, so that it becomes difficult to hold the inorganic fine particles in the coating layer, and the strength of the coating layer is caused by the detachment of the inorganic fine particles. Is not preferred because it may decrease. On the other hand, when it is smaller than 100 nm, the effect of reinforcing the coating layer by the inorganic fine particles cannot be sufficiently obtained, and the coating layer may not be sufficiently scraped or peeled off due to a long-term stirring stress.

  The volume average particle size of the inorganic fine particles can be measured using, for example, a laser Doppler / dynamic light scattering particle size distribution device.

  The inorganic fine particles are not particularly limited as long as the above conditions are satisfied, and can be appropriately selected from conventionally known materials according to the purpose. For example, silica, titanium oxide, alumina, potassium titanate, Examples thereof include barium titanate and aluminum borate, and two or more of them may be used in combination.

  In the present invention, the inorganic fine particles are further preferably metal oxide fine particles whose surface is subjected to conductive treatment. Such a conductive treatment method includes aluminum, zinc, copper, nickel, silver, or an alloy thereof, zinc oxide, titanium oxide, tin oxide, antimony oxide, indium oxide, oxidation on the surface of the metal oxide fine particles. Examples thereof include a method of coating bismuth, tin-doped indium oxide, antimony-doped tin oxide, zirconium oxide, and the like in the form of a solid solution or fusion. Among these, tin oxide, indium oxide, and a method of conducting a conductive treatment using indium oxide doped with tin are particularly preferable.

The content of the inorganic fine particles is appropriately selected depending on the thickness of the coating layer and the material constituting the coating layer, but the range of 1% by mass to 40% by mass of the entire coating layer is preferable, and 15% by mass to 30% by mass. % Range is more preferred.
When the content is less than 1% by mass, the reinforcing effect of the coating layer may not be sufficiently obtained, which is not preferable. On the other hand, if it exceeds 40% by mass, the ratio of the binder resin constituting the coating layer decreases, it becomes difficult to hold the inorganic fine particles firmly in the coating layer, and the inorganic fine particles are liable to be detached. Since the durability of the coating layer may deteriorate, it is not preferable.

  The content of the coating layer in the carrier is preferably 5% by mass or more, and more preferably 5% by mass or more and 10% by mass or less.

The thickness of the coating layer is preferably 0.1 μm to 5 μm, and more preferably 0.3 μm to 2 μm.
Here, the thickness of the coating layer is, for example, 50 or more carrier cross sections using a transmission electron microscope (TEM) or a scanning transmission electron microscope (STEM) after creating a carrier cross section with FIB (focused ion beam). Can be calculated as an average value of the obtained film thicknesses.

―Method of forming carrier coating layer―
The method for forming the coating layer on the carrier is not particularly limited, and a conventionally known coating layer forming method can be used, and the above-described coating layer raw materials including the binder resin or the binder resin precursor are dissolved. The method of apply | coating a coating layer solution on the surface of a core material using the spraying method or the immersion method etc. is mentioned. It is preferable to promote the polymerization reaction of the binder resin or the binder resin precursor by applying the coating layer solution on the surface of the core material and heating the carrier on which the coating layer is formed. The heat treatment may be performed subsequently in the coating apparatus after the coating layer is formed, or may be performed by another heating means such as a normal electric furnace or a firing kiln after the coating layer is formed.

  The heat treatment temperature varies depending on the constituent material of the coating layer to be used, and is not generally determined, but is preferably about 120 ° C. to 350 ° C., and particularly preferably not higher than the decomposition temperature of the constituent material of the coating layer. The decomposition temperature of the coating layer constituting material is preferably an upper limit temperature up to about 220 ° C., and the heat treatment time is preferably about 5 minutes to 120 minutes.

―Physical properties of the carrier―
The volume average particle size of the carrier used in the present invention is preferably in the range of 20 to 65 μm, and more preferably in the range of 20 to 55 μm.
When the volume average particle diameter of the carrier is less than 20 μm, carrier adhesion due to the decrease in uniformity of the core material particles may occur. It is not preferable because a fine image may not be obtained.

  The method for measuring the volume average particle size is not particularly limited as long as it is a device capable of measuring the particle size distribution, and for example, it is measured using a Microtrac particle size distribution analyzer: Model HRA9320-X100 (manufactured by Nikkiso Co., Ltd.). Can do.

The volume resistivity of the carrier used in the present invention is preferably 10 [log (Ω · cm)] or more and 16 [log (Ω · cm)] or less, preferably 10 [log (Ω · cm)] or more and 14 It is more preferably [log (Ω · cm)] or less.
When the volume resistivity is less than 10 [log (Ω · cm)], carrier adhesion occurs in the non-image area, and when the volume resistivity is more than 16 [log (Ω · cm)], it is not preferable at the edge portion during development. A so-called edge effect in which the image density is emphasized becomes remarkable, which is not preferable. The volume resistivity is arbitrarily adjusted within the range by adjusting the film thickness of the carrier coating layer and the content of the phosphorus-doped conductive tin oxide fine particles and the inorganic fine particles (conductive fine particles) as necessary. Is possible.

  Examples of the volume resistivity measuring method include a method using an apparatus as shown in FIG. Specifically, a carrier (3) is filled in a cell comprising a container (2) made of a fluororesin (2) containing an electrode (1a) and an electrode (1b) having a distance between electrodes of 0.2 cm and a surface area of 2.5 cm × 4 cm. Tapping is performed under the conditions of drop height: 1 cm, tapping speed: 30 times / min, tapping frequency: 10 times. Next, a DC voltage of 1000 V was applied between both electrodes, and a resistance value r [Ω] after 30 seconds was measured with a high resistance meter 4329A (manufactured by Yokogawa Hewlett-Packard Co., Ltd .: High Resistance Meter). The volume resistivity R [log (Ω · cm)] can be calculated by calculating as follows.

(Developer)
The developer of the present invention is a two-component developer containing the carrier of the present invention and a toner.
As for the mixing ratio of the toner and the carrier in the developer, the mass ratio of the toner to the carrier is preferably 2.0 to 12.0% by mass, and more preferably 2.5 to 10.0% by mass.
(toner)
The toner in the two-component developer of the present invention is not particularly limited and can be appropriately selected according to the purpose from those used as electrophotographic toner. Usually, the toner includes at least a binder resin and a toner. It contains a colorant, and contains a release agent, a charge control agent, and other components as required.

  The method for producing the toner is not particularly limited and may be appropriately selected depending on the intended purpose. It is a pulverization method, a suspension in which an oil phase is emulsified, suspended or aggregated in an aqueous medium to form toner base particles. Examples include a polymerization method, an emulsion polymerization method, and a polymer suspension method.

―Binder resin―
The binder resin is not particularly limited and may be appropriately selected from known ones according to the purpose. For example, styrene such as polystyrene, poly-p-styrene, polyvinyltoluene, or a homopolymer of a substituted product thereof. Styrene-p-chlorostyrene copolymer, styrene-propylene copolymer, styrene-vinyltoluene copolymer, styrene-methyl acrylate copolymer, styrene-ethyl acrylate copolymer, styrene-methacrylic acid copolymer Polymerization unit, styrene-methyl methacrylate copolymer, styrene-ethyl methacrylate copolymer, styrene-butyl methacrylate copolymer, styrene-α-chloromethacrylate methyl copolymer, styrene-acrylonitrile copolymer Polymer, styrene-vinyl methyl ether copolymer, styrene-vinyl methyl ketone Copolymer, styrene-butadiene copolymer, styrene-isopropyl copolymer, styrene-maleic ester copolymer, and other styrene copolymers; polymethyl methacrylate resin, polybutyl methacrylate resin, polyvinyl chloride resin, Polyvinyl acetate resin, polyethylene resin, polyester resin, polyurethane resin, epoxy resin, polyvinyl butyral resin, polyacrylic acid resin, rosin resin, modified rosin resin, terpene resin, phenol resin, aliphatic or aromatic hydrocarbon resin, aromatic Based petroleum resin and the like. These may be used individually by 1 type and may use 2 or more types together.

―Colorant―
The colorant is not particularly limited and may be appropriately selected from known dyes and pigments according to the purpose. For example, carbon black, nigrosine dye, iron black, naphthol yellow S, Hansa yellow (10G, 5G, G), Cadmium yellow, Yellow iron oxide, Ocher, Yellow lead, Titanium yellow, Polyazo yellow, Oil yellow, Hansa yellow (GR, A, RN, R), Pigment yellow L, Benzidine yellow (G, GR) , Permanent Yellow (NCG), Vulcan Fast Yellow (5G, R), Tartrazine Lake, Quinoline Yellow Lake, Anthrazan Yellow BGL, Isoindolinone Yellow, Bengala, Red Tan, Lead Zhu, Cadmium Red, Cadmium Mercury Red, Antimony Zhu, Permanent Red 4R, Parallel , Faise red, parachloroortho nitroaniline red, risor fast scarlet G, brilliant fast scarlet, brilliant carmine BS, permanent red (F2R, F4R, FRL, FRLL, F4RH), fast scarlet VD, Belkan Fast Rubin B, brilliant Scarlet G, Resol Rubin GX, Permanent Red F5R, Brilliant Carmine 6B, Pigment Scarlet 3B, Bordeaux 5B, Toluidine Maroon, Permanent Bordeaux F2K, Helio Bordeaux BL, Bordeaux 10B, Bon Maroon Light, Bon Maroon Medium, Eosin Lake, Rhodamine Lake B , Rhodamine lake Y, alizarin lake, thioindigo red B, thioindigo maroon, oil Quinacridone red, pyrazolone red, polyazo red, chrome vermilion, benzidine orange, perinone orange, oil orange, cobalt blue, cerulean blue, alkaline blue rake, peacock blue rake, Victoria blue rake, metal-free phthalocyanine blue, phthalocyanine blue, Fast Sky Blue, Indanthrene Blue (RS, BC), Indigo, Ultramarine Blue, Bitumen, Anthraquinone Blue, Fast Violet B, Methyl Violet Lake, Cobalt Purple, Manganese Purple, Dioxane Violet, Anthraquinone Violet, Chrome Green, Zinc Green, Oxidation Chrome, Pyridian, Emerald Green, Pigment Green B, Naphthol Green B, Green Gold, Acid Glee Nlake, Malachite Green Lake, Phthalocyanine Green, Anthraquinone Green, Titanium Oxide, Zinc Hana, Litobon and the like. These may be used individually by 1 type and may use 2 or more types together.
The content of the colorant in the toner is preferably 1% by mass to 15% by mass, and more preferably 3% by mass to 10% by mass.

  The colorant may be used as a master batch combined with a resin. The resin is not particularly limited and may be appropriately selected from known ones according to the purpose. For example, styrene or a substituted polymer thereof, styrene copolymer, polymethyl methacrylate resin, polybutyl Methacrylate resin, polyvinyl chloride resin, polyvinyl acetate resin, polyethylene resin, polypropylene resin, polyester resin, epoxy resin, epoxy polyol resin, polyurethane, polyamide, polyvinyl butyral, polyacrylic acid resin, rosin, modified rosin, terpene resin, fat Aromatic hydrocarbon resin, alicyclic hydrocarbon resin, aromatic petroleum resin, chlorinated paraffin, paraffin and the like. These may be used individually by 1 type and may use 2 or more types together.

-Release agent-
There is no restriction | limiting in particular as said mold release agent, According to the objective, it can select suitably from well-known things, For example, waxes etc. are mentioned suitably.
Examples of the waxes include carbonyl group-containing waxes, polyolefin waxes, and long-chain hydrocarbons. These may be used individually by 1 type and may use 2 or more types together. Among these, a carbonyl group-containing wax is preferable.
Examples of the carbonyl group-containing wax include polyalkanoic acid esters, polyalkanol esters, polyalkanoic acid amides, polyalkylamides, dialkyl ketones, and the like. Examples of the polyalkanoic acid ester include carnauba wax, montan wax, trimethylolpropane tribehenate, pentaerythritol tetrabehenate, pentaerythritol diacetate dibehenate, glycerin tribehenate, 1,18-octadecane. Examples thereof include diol distearate. Examples of the polyalkanol ester include tristearyl trimellitic acid and distearyl maleate. Examples of the polyalkanoic acid amide include dibehenyl amide. Examples of the polyalkylamide include trimellitic acid tristearylamide. Examples of the dialkyl ketone include distearyl ketone. Of these carbonyl group-containing waxes, polyalkanoic acid esters are particularly preferred.
Examples of the polyolefin wax include polyethylene wax and polypropylene wax.
Examples of the long chain hydrocarbon include paraffin wax and sazol wax.

There is no restriction | limiting in particular as melting | fusing point of the said mold release agent, Although it can select suitably according to the objective, 40 to 160 degreeC is preferable, 50 to 120 degreeC is more preferable, and 60 to 90 degreeC is further. preferable.
If the melting point is less than 40 ° C., the wax may adversely affect the heat-resistant storage stability, and if it exceeds 160 ° C., a cold offset may easily occur during fixing at a low temperature.
The melt viscosity of the release agent is preferably 5 cps to 1,000 cps, more preferably 10 cps to 100 cps, as measured at a temperature 20 ° C. higher than the melting point of the wax.
If the melt viscosity is less than 5 cps, the releasability may be lowered, and if it exceeds 1,000 cps, the effect of improving hot offset resistance and low-temperature fixability may not be obtained.

There is no restriction | limiting in particular as content in the said toner of the said mold release agent, Although it can select suitably according to the objective, 1 mass%-40 mass% are preferable, and 3 mass%-30 mass% are more preferable. .
When the content exceeds 40% by mass, the fluidity of the toner may be deteriorated.

―Charge control agent―
The charge control agent is not particularly limited, and a positive or negative charge control agent can be appropriately selected and used depending on whether the charge charged on the photoconductor is positive or negative.
As the negative charge control agent, for example, a resin or compound having an electron donating functional group, an azo dye, a metal complex of an organic acid, or the like can be used. Specifically, Bontron (product numbers: S-31, S-32, S-34, S-36, S-37, S-39, S-40, S-44, E-81, E-82, E -84, E-86, E-88, A, 1-A, 2-A, 3-A) (all manufactured by Orient Chemical Co., Ltd.); Kaya Charge (product numbers: N-1, N-2) Kaya Set Black (Part No .: T-2, 004) (all manufactured by Nippon Kayaku Co., Ltd.); Eisenspiron Black (T-37, T-77, T-95, TRH, TNS-2) (all Also manufactured by Hodogaya Chemical Co., Ltd.); FCA-1001-N, FCA-1001-NB, FCA-1001-NZ (all manufactured by Fujikura Kasei Co., Ltd.), and the like.
As the positive charge control agent, for example, a basic compound such as a nigrosine dye, a cationic compound such as a quaternary ammonium salt, a metal salt of a higher fatty acid, or the like can be used. Specifically, Bontron (part numbers: N-01, N-02, N-03, N-04, N-05, N-07, N-09, N-10, N-11, N-13, P -51, P-52, AFP-B) (all manufactured by Orient Chemical Co., Ltd.); TP-302, TP-415, TP-4040 (all manufactured by Hodogaya Chemical Co., Ltd.); Copy Blue PR , Copy charge (part numbers: PX-VP-435, NX-VP-434) (both manufactured by Hoechst); FCA (part numbers: 201, 201-B-1, 201-B-2, 201-B-3) , 201-PB, 201-PZ, 301) (all manufactured by Fujikura Kasei Co., Ltd.); PLZ (product numbers: 1001, 2001, 6001, 7001) (all manufactured by Shikoku Kasei Kogyo Co., Ltd.), and the like. .
These may be used individually by 1 type and may use 2 or more types together.

  The addition amount of the charge control agent is determined by the toner production method including the type of the binder resin and the dispersion method, and is not limited to a specific value. 1 mass%-10 mass% are preferable, and 0.2 mass%-5 mass% are more preferable. When the addition amount exceeds 10% by mass, the chargeability of the toner is too high, the effect of the charge control agent is reduced, the electrostatic attraction force with the developing roller is increased, the flowability of the developer is reduced, and the image The density may be lowered, and if it is less than 0.1% by mass, the charge start-up property and the charge amount are not sufficient, and the toner image may be easily affected.

  In addition to the binder resin, the release agent, the colorant, and the charge control agent, the toner material includes inorganic fine particles, a fluidity improver, a cleaning property improver, a magnetic material, a metal soap, and the like as necessary. Can be added.

The inorganic fine particles are not particularly limited and can be appropriately selected according to the purpose. For example, silica, titania, alumina, cerium oxide, strontium titanate, calcium carbonate, magnesium carbonate, calcium phosphate, and the like can be used. It is more preferable to use silica fine particles hydrophobized with silicone oil, hexamethyldisilazane, or the like, or titanium oxide subjected to a specific surface treatment.
Examples of the silica fine particles include, for example, Aerosil (product numbers: 130, 200 V, 200 CF, 300, 300 CF, 380, OX50, TT600, MOX80, MOX170, COK84, RX200, RY200, R972, R974, R976, R805, R811, R812, T805, R202, VT222, RX170, RXC, RA200, RA200H, RA200HS, RM50, RY200, REA200) (all manufactured by Nippon Aerosil Co., Ltd.); HDK (Part No .: H20, H2000, H3004, H2000 / 4, H2050EP, H2015EP) , H3050EP, KHD50), HVK2150 (all manufactured by Wacker Chemical Co., Ltd.); Cabozil (Part No .: L-90, LM-130, LM-150, M-5, PTG, MS) 55, H-5, HS-5, EH-5, LM-150D, M-7D, MS-75D, TS-720, TS-610, TS-530) (all manufactured by Cabot) Can do.
The addition amount of the inorganic fine particles is preferably 0.1% by mass to 5.0% by mass and more preferably 0.8% by mass to 3.2% by mass with respect to the toner base particles.

  The method for producing the toner is not particularly limited and may be appropriately selected depending on the intended purpose. Examples thereof include a pulverization method, a monomer containing a specific crystalline polymer and a polymerizable monomer. A polymerization method (suspension polymerization method, emulsion polymerization method) for directly polymerizing the composition in an aqueous phase, a composition containing a specific crystalline polymer and an isocyanate group-containing prepolymer in an aqueous phase with amines Examples include a direct addition / crosslinking polyaddition reaction method, a polyaddition reaction method using an isocyanate group-containing prepolymer, a method of dissolving in a solvent, removing the solvent, and pulverizing, and a melt spraying method.

The pulverization method is, for example, a method of obtaining the toner base particles by melting or kneading the toner material, pulverizing, classifying or the like. In the case of the pulverization method, for the purpose of increasing the average circularity of the toner, the shape may be controlled by applying a mechanical impact force to the obtained toner base particles. In this case, the mechanical impact force can be applied to the toner base particles using a device such as a hybridizer or mechanofusion.
The above toner materials are mixed, and the mixture is charged into a melt kneader and melt kneaded. As the melt kneader, for example, a uniaxial continuous kneader, a biaxial continuous kneader, or a batch kneader using a roll mill can be used. For example, KTK type twin screw extruder manufactured by Kobe Steel, TEM type extruder manufactured by Toshiba Machine Co., Ltd., twin screw extruder manufactured by Casey Kay, PCM type twin screw extruder manufactured by Ikegai Co., Ltd. Used for. This melt-kneading is preferably performed under appropriate conditions so as not to cause the molecular chains of the binder resin to be broken. Specifically, the melt kneading temperature is performed with reference to the softening point of the binder resin. If the temperature is higher than the softening point, cutting is severe, and if the temperature is too low, dispersion may not proceed.

  In the pulverization, the kneaded product obtained by the kneading is pulverized. In this pulverization, it is preferable that the kneaded material is first coarsely pulverized and then finely pulverized. At this time, a method of pulverizing by colliding with a collision plate in a jet stream, pulverizing particles by colliding with each other in a jet stream, or pulverizing with a narrow gap between a mechanically rotating rotor and a stator is preferably used.

In the classification, the pulverized product obtained by the pulverization is classified and adjusted to particles having a predetermined particle diameter. The classification can be performed by removing the fine particle portion by, for example, a cyclone, a decanter, centrifugation, or the like.
After the pulverization and classification are completed, the pulverized product is classified into an air stream by centrifugal force or the like to produce a toner having a predetermined particle size.

The suspension polymerization method is an oil-soluble polymerization initiator, emulsification described later in an aqueous medium in which a colorant, a release agent and the like are dispersed in a polymerizable monomer and a surfactant and other solid dispersants are contained. Emulsified and dispersed by the method. Thereafter, a polymerization reaction is performed to form particles, and then wet processing for attaching inorganic fine particles to the toner particle surfaces in the present invention may be performed. At that time, it is preferable to wash the excess surfactant or the like and apply the treatment to the removed toner particles.
Examples of the polymerizable monomer include acids such as acrylic acid, methacrylic acid, α-cyanoacrylic acid, α-cyanomethacrylic acid, itaconic acid, crotonic acid, fumaric acid, maleic acid or maleic anhydride; acrylamide, Methacrylamide, diacetone acrylamide, or these methylol compounds; vinyl pyridine, vinyl pyrrolidone, vinyl imidazole, ethyleneimine, dimethylaminoethyl methacrylate and other (meth) acrylates that have amino groups are used on the toner particle surface. Functional groups can be introduced.
Further, by selecting a dispersant having an acid group or a basic group as the dispersant to be used, the dispersant can be adsorbed and left on the particle surface to introduce a functional group.

  As the emulsion polymerization method, a water-soluble polymerization initiator and a polymerizable monomer are emulsified in water using a surfactant, and a latex is synthesized by a usual emulsion polymerization method. Separately, a dispersion in which a colorant, a release agent and the like are dispersed in an aqueous medium is prepared, and after mixing, the toner is aggregated to a toner size and heat-fused to obtain a toner. Thereafter, wet processing of inorganic fine particles described later may be performed. A functional group can be introduced on the surface of the toner particles by using a latex similar to the monomer used in the suspension polymerization method.

Among these, since the selectivity of the resin is high, the low-temperature fixability is high, the granulation property is excellent, and the particle size, particle size distribution, and shape can be easily controlled. And a polymer capable of reacting with the active hydrogen group-containing compound is dissolved or dispersed in an organic solvent to prepare a toner solution, and then the toner solution is emulsified or dispersed in an aqueous medium. In the aqueous medium, the active hydrogen group-containing compound and a polymer capable of reacting with the active hydrogen group-containing compound are reacted to form an adhesive substrate in the form of particles, and the organic solvent is What is obtained by removing is suitable.
Examples of the toner material include an adhesive base obtained by reacting an active hydrogen group-containing compound, a polymer capable of reacting with the active hydrogen group-containing compound, a binder resin, a charge control agent, and a colorant. Etc., and further, if necessary, other components such as resin fine particles and a release agent.

  Further, in order to improve the fluidity, storage stability, developability and transferability of the toner, inorganic fine particles such as hydrophobic silica fine powder may be further added to and mixed with the toner base particles produced as described above. For mixing the additives, a general powder mixer is used, but it is preferable to equip a jacket or the like to adjust the internal temperature. In order to change the load history applied to the additive, the additive may be added midway or gradually. In this case, you may change the rotation speed, rolling speed, time, temperature, etc. of a mixer. Alternatively, a strong load may be applied first, then a relatively weak load, or vice versa. Examples of the mixing equipment that can be used include a V-type mixer, a rocking mixer, a Ladige mixer, a Nauter mixer, and a Henschel mixer. Next, the toner is obtained by passing through a sieve of 250 mesh or more to remove coarse particles and aggregated particles.

  The shape, size, etc. of the toner are not particularly limited and can be appropriately selected according to the purpose. The average circularity, volume average particle size, volume average particle size and number are as follows. It is preferable to have a ratio (volume average particle diameter / number average particle diameter) to the average particle diameter.

The average circularity is a value obtained by dividing the perimeter of an equivalent circle having the same projected shape as the toner shape by the perimeter of the actual particles, and is preferably 0.900 to 0.980, for example, 0.950 to 0 .975 is more preferred. In addition, it is preferable that the particles having an average circularity of less than 0.94 is 15% or less.
If the average circularity is less than 0.900, satisfactory transferability and a high-quality image free from dust may not be obtained. If it exceeds 0.980, image formation employing blade cleaning or the like is employed. In the system, defective cleaning occurs on the photoconductor and transfer belt, and in the case of image formation with a high image area ratio such as a photographic image, an untransferred image is formed due to defective paper feeding, etc. As a result, the accumulated toner may become a transfer residual toner on the photoconductor, which may cause background smearing of the image, or may contaminate the charging roller for charging the photoconductor in contact with the original charging ability. It may become impossible to demonstrate.

  The average circularity is measured using a flow particle image analyzer (“FPIA-2100”, manufactured by Sysmex Corporation), and analyzed using analysis software (FPIA-2100 Data Processing Program for FPIA version 00-10). It was. Specifically, 0.1 to 0.5 ml of 10% by weight surfactant (alkylbenzene sulfonate, Neogen SC-A, manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) is added to a 100 ml glass beaker, and each toner 0 is added. 0.1 to 0.5 g was added, and the mixture was mixed with a micropartel, and then 80 mL of ion-exchanged water was added. The obtained dispersion was subjected to a dispersion treatment for 3 minutes with an ultrasonic disperser (manufactured by Honda Electronics Co., Ltd.). The shape and distribution of the toner were measured using the FPIA-2100 until the concentration of the dispersion reached 5,000 to 15,000 / μL. In this measurement method, it is important that the concentration of the dispersion is 5,000 to 15,000 / μL from the viewpoint of measurement reproducibility of average circularity. In order to obtain the concentration of the dispersion, it is necessary to change the conditions of the dispersion, that is, the amount of surfactant to be added and the amount of toner. The amount of the surfactant varies depending on the hydrophobicity of the toner as in the measurement of the toner particle diameter described above. If it is added in a large amount, noise due to bubbles is generated, and if it is too small, the toner cannot be sufficiently wetted. It will be enough. The amount of toner added varies depending on the particle size, and is small when the particle size is small, and needs to be increased when the particle size is large. When the toner particle size is 3 μm to 10 μm, the toner amount is 0.1 g to 0.00. By adding 5 g, the dispersion concentration can be adjusted to 5,000 / μl to 15,000 / μl.

The volume average particle diameter of the toner is not particularly limited and may be appropriately selected depending on the intended purpose. For example, it is preferably 3 μm to 10 μm, and more preferably 3 μm to 8 μm.
When the volume average particle size is less than 3 μm, in the case of a two-component developer, the toner may be fused to the surface of the carrier during long-term agitation in the developing device, and the charging ability of the carrier may be reduced. Therefore, it becomes difficult to obtain a high-resolution and high-quality image, and when the balance of the toner in the developer is performed, the variation in the toner particle size may increase.

  The ratio of the volume average particle diameter to the number average particle diameter (volume average particle diameter / number average particle diameter) in the toner is preferably 1.00 to 1.25, more preferably 1.10 to 1.25.

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

  The coloration of the toner is not particularly limited and may be appropriately selected according to the purpose, and may be at least one selected from black toner, cyan toner, magenta toner, and yellow toner. Can be obtained by appropriately selecting the type of the colorant, and is preferably a color toner.

(Container with developer)
The developer of the present invention can be used in a container.
There is no restriction | limiting in particular as said container, It can select suitably from well-known things, For example, what has a developer container main body and a cap etc. are mentioned suitably.
The developer container body is not particularly limited in size, shape, structure, material, and the like, and can be appropriately selected according to the purpose. For example, the shape is preferably cylindrical. A spiral irregularity is formed on the peripheral surface, the developer as the contents can be transferred to the discharge port side by rotating, and a part or all of the spiral part has a bellows function, Etc. are particularly preferred.
The material of the developer container main body is not particularly limited, and those having good dimensional accuracy are preferable. For example, a resin is preferable. Among them, for example, polyester resin, polyethylene resin, polypropylene resin, polystyrene resin, Preferable examples include vinyl chloride resin, polyacrylic acid, polycarbonate resin, ABS resin, polyacetal resin and the like.
The developer-containing container is easy to store and transport, has excellent handleability, and can be suitably used for replenishing the developer by being detachably attached to an image forming apparatus described later.

(Image forming method and image forming apparatus)
The image forming method of the present invention includes at least an electrostatic latent image forming step, a developing step, a transfer step, and a fixing step, and other steps appropriately selected as necessary, for example, a static elimination step, a cleaning step. , Including recycling process, control process, etc.
The image forming apparatus used in the present invention includes at least an electrostatic latent image carrier, an electrostatic latent image forming unit, a developing unit, a transfer unit, and a fixing unit. It comprises other selected means, for example, static elimination means, cleaning means, recycling means, control means and the like.

-Electrostatic latent image forming process and electrostatic latent image forming means-
The electrostatic latent image forming step is a step of forming an electrostatic latent image on the electrostatic latent image carrier.
The electrostatic latent image carrier (sometimes referred to as “electrophotographic photosensitive member” or “photosensitive member”) is not particularly limited in terms of material, shape, structure, size, etc. Although it can be selected as appropriate, the shape thereof is preferably a drum shape, and examples of the material thereof include inorganic photoreceptors such as amorphous silicon and selenium, organic photoreceptors (OPC) such as polysilane and phthalopolymethine, and the like. Is mentioned. Among these, amorphous silicon or the like is preferable in terms of long life.

  The formation of the electrostatic latent image can be performed, for example, by uniformly charging the surface of the electrostatic latent image carrier and then performing imagewise exposure, and is performed by the electrostatic latent image forming unit. be able to. The electrostatic latent image forming means includes, for example, at least a charger that uniformly charges the surface of the electrostatic latent image carrier and an exposure device that exposes the surface of the electrostatic latent image carrier imagewise. Prepare.

The charging can be performed, for example, by applying a voltage to the surface of the electrostatic latent image carrier using the charger.
The charger is not particularly limited and may be appropriately selected depending on the purpose. For example, a known contact charging device including a conductive or semiconductive roll, brush, film, rubber blade, etc. And non-contact chargers utilizing corona discharge such as corotrons and corotrons.
The charger is preferably one that is arranged in contact or non-contact with the electrostatic latent image carrier and charges the surface of the electrostatic latent image carrier by applying a direct current and an alternating voltage.
Further, the charger is a charging roller disposed in a non-contact proximity to the electrostatic latent image carrier via a gap tape, and the electrostatic latent image is carried by applying a direct current and an alternating voltage to the charging roller. Those that charge the body surface are preferred.

The exposure can be performed, for example, by exposing the surface of the latent electrostatic image bearing member imagewise using the exposure device.
The exposure device is not particularly limited as long as it can expose the surface of the latent electrostatic image bearing member charged by the charger so as to form an image to be formed, and is appropriately selected according to the purpose. For example, various exposure devices such as a copying optical system, a rod lens array system, a laser optical system, and a liquid crystal shutter optical system can be used.
In the present invention, a back light system in which imagewise exposure is performed from the back side of the electrostatic latent image carrier may be employed.

-Development process and development means-
The developing step is a step of developing the electrostatic latent image using the developer of the present invention to form a visible image.
The visible image can be formed, for example, by developing the electrostatic latent image using the developer of the present invention, and can be performed by the developing unit.
The developing means is not particularly limited as long as it can be developed using, for example, the developer of the present invention, and can be appropriately selected from known ones. For example, the developer of the present invention is accommodated. In addition, it is preferable to have at least a developing unit capable of applying the developer to the electrostatic latent image in a contact or non-contact manner, and a developing unit including the developer-containing container is more preferable.

  The developing device may be a single color developing device or a multicolor developing device.For example, a stirrer for charging the developer by friction stirring and a rotatable magnet roller. What has is mentioned suitably.

In the developing device, for example, the toner and the carrier are mixed and agitated, and the toner is charged by friction at that time, and held on the surface of the rotating magnet roller in a raised state to form a magnetic brush. . Since the magnet roller is disposed in the vicinity of the electrostatic latent image carrier (photoconductor), a part of the toner constituting the magnetic brush formed on the surface of the magnet roller is electrically attracted. It moves to the surface of the electrostatic latent image carrier (photoconductor) by force. As a result, the electrostatic latent image is developed with the toner, and a visible image is formed with the toner on the surface of the electrostatic latent image carrier (photoconductor).
The developer accommodated in the developing device is the developer of the present invention.

―Transfer process and transfer means―
The transfer step is a step of transferring the visible image onto a recording medium. After the primary transfer of the visible image onto the intermediate transfer member using an intermediate transfer member, the visible image is transferred onto the recording medium. A primary transfer step of forming a composite transfer image by transferring a visible image onto an intermediate transfer body using two or more colors, preferably full color toner as the toner, and a composite transfer image; A mode including a secondary transfer step of transferring the transfer image onto the recording medium is more preferable.
The transfer can be performed, for example, by charging the latent electrostatic image bearing member (photoconductor) of the visible image using a transfer charger, and can be performed by the transfer unit. The transfer means includes a primary transfer means for transferring a visible image onto an intermediate transfer member to form a composite transfer image, and a secondary transfer means for transferring the composite transfer image onto a recording medium. Embodiments are preferred.
The intermediate transfer member is not particularly limited and may be appropriately selected from known transfer members according to the purpose. For example, a transfer belt and the like are preferable.

The transfer means (the primary transfer means and the secondary transfer means) is a transfer for peeling and charging the visible image formed on the electrostatic latent image carrier (photoconductor) to the recording medium side. It is preferable to have at least a vessel. The number of the transfer means may be one, or two or more.
Examples of the transfer device include a corona transfer device using corona discharge, a transfer belt, a transfer roller, a pressure transfer roller, and an adhesive transfer device.
The recording medium is not particularly limited and can be appropriately selected from known recording media (recording paper).

―Fixing process and fixing means―
The fixing step is a step of fixing the visible image transferred to the recording medium using a fixing device, and may be performed each time the developer of each color is transferred to the recording medium, or the developer of each color. On the other hand, it may be carried out at the same time in a state where these are laminated.
There is no restriction | limiting in particular as said fixing device, Although it can select suitably according to the objective, A well-known heating-pressing means is suitable. Examples of the heating and pressing means include a combination of a heating roller and a pressing roller, a combination of a heating roller, a pressing roller, and an endless belt.
The fixing device includes a heating body including a heating element, a film in contact with the heating body, and a pressure member in pressure contact with the heating body through the film, and the film and the pressure member It is preferably a unit that heats and fixes a recording medium on which an unfixed image is formed. The heating in the heating and pressing means is usually preferably 80 ° C to 200 ° C.
In the present invention, for example, a known optical fixing device may be used together with or in place of the fixing step and the fixing unit depending on the purpose.

The neutralization step is a step of performing neutralization by applying a neutralization bias to the electrostatic latent image carrier, and can be suitably performed by a neutralization unit.
The neutralization means is not particularly limited, and may be appropriately selected from known neutralizers as long as it can apply a neutralization bias to the electrostatic latent image carrier. Preferably mentioned.

The cleaning step is a step of removing the toner remaining on the electrostatic latent image carrier, and can be suitably performed by a cleaning unit.
The cleaning unit is not particularly limited, and may be selected from known cleaners as long as it can remove the toner remaining on the electrostatic latent image carrier. For example, a magnetic brush cleaner Suitable examples include electrostatic brush cleaners, magnetic roller cleaners, blade cleaners, brush cleaners, web cleaners, and the like.

The recycling step is a step of recycling the toner removed by the cleaning step to the developing unit, and can be suitably performed by the recycling unit.
There is no restriction | limiting in particular as said recycling means, A well-known conveyance means etc. are mentioned.

The control step is a step of controlling each step, and each step can be suitably performed by a control means.
The control means is not particularly limited as long as the movement of each means can be controlled, and can be appropriately selected according to the purpose. Examples thereof include devices such as a sequencer and a computer.

  FIG. 2 shows a first example of an image forming apparatus used in the present invention. The image forming apparatus (100A) includes a photosensitive drum (10), a charging roller (20), an exposure device (not shown), a developing device (40), an intermediate transfer belt (50), and a cleaning blade. A cleaning device (60) and a static elimination lamp (70) are provided.

  The intermediate transfer belt (50) is an endless belt stretched by three rollers (51) arranged on the inner side, and can move in the direction of the arrow in the figure. A part of the three rollers (51) also functions as a transfer bias roller capable of applying a transfer bias (primary transfer bias) to the intermediate transfer belt (50). A cleaning device (90) having a cleaning blade is disposed in the vicinity of the intermediate transfer belt 50. Further, a transfer roller (80) capable of applying a transfer bias (secondary transfer bias) for transferring the toner image to the recording paper P is disposed to face the intermediate transfer belt (50). Around the intermediate transfer belt (50), a corona charging device (58) for applying a charge to the toner image transferred to the intermediate transfer belt (50) is provided in the rotational direction of the intermediate transfer belt (50). On the other hand, it is disposed between the contact portion between the photosensitive drum (10) and the intermediate transfer belt (50) and the contact portion between the intermediate transfer belt (50) and the recording paper (P).

  The developing device (40) includes a developing belt (41), a black developing unit (45K), a yellow developing unit (45Y), a magenta developing unit (45M), and a cyan developing unit (45C) provided around the developing belt (41). ). Each color developing unit (45) includes a developer container (42), a developer supply roller (43), and a developing roller (44). The developing belt (41) is an endless belt stretched by a plurality of belt rollers, and can move in the direction of the arrow in the figure. Further, a part of the developing belt (41) is in contact with the photosensitive drum (10).

  Next, a method for forming an image using the image forming apparatus (100A) will be described. First, the surface of the photosensitive drum (10) is uniformly charged using the charging roller (20), and then the exposure light (L) is applied to the photosensitive drum (10) using an exposure device (not shown). Exposure is performed to form an electrostatic latent image. Next, the electrostatic latent image formed on the photosensitive drum (10) is developed with toner supplied from the developing device (40) to form a toner image. Further, the toner image formed on the photosensitive drum (10) is transferred (primary transfer) onto the intermediate transfer belt (50) by the transfer bias applied from the roller (51), and then transferred to the transfer roller (80). ) Is transferred (secondary transfer) onto the transfer paper (95) by the transfer bias applied from (2). On the other hand, after the toner remaining on the surface of the photosensitive drum (10) on which the toner image has been transferred to the intermediate transfer belt (50) is removed by the cleaning device (60), the charge is eliminated by the neutralization lamp (70).

  FIG. 3 shows a second example of the image forming apparatus used in the present invention. In the image forming apparatus (100B), the black developing unit (45K), the yellow developing unit (45Y), the magenta developing unit (45M), and cyan are arranged around the photosensitive drum (10) without providing the developing belt (41). The developing unit (45C) has the same configuration as that of the image forming apparatus (100A) except that the developing unit (45C) is directly opposed.

FIG. 4 shows a third example of the image forming apparatus used in the present invention. The image forming apparatus (100C) is a tandem color image forming apparatus, and includes a copying apparatus main body (150), a paper feed table (200), a scanner (300), and an automatic document feeder: ADF (400). Prepare.
The intermediate transfer belt (50) provided at the center of the copying machine main body (150) is an endless belt stretched around three rollers (14), (15) and (16). , Can move in the direction of the arrow. In the vicinity of the roller (15), a cleaning device (90) having a cleaning blade for removing toner remaining on the intermediate transfer belt (50) on which the toner image has been transferred onto the recording paper is disposed. The yellow, cyan, magenta and black image forming units (120Y), (120C), (120C) are opposed to the intermediate transfer belt (50) stretched by the rollers (14) and (15) and along the transport direction. 120M) and (120K) are juxtaposed. An exposure device (30) is disposed in the vicinity of the image forming unit (120). Further, a secondary transfer belt (24) is arranged on the side of the intermediate transfer belt (50) opposite to the side where the image forming unit (120) is arranged. The secondary transfer belt (24) is an endless belt stretched between a pair of rollers (22) and (23), and a recording sheet and an intermediate transfer belt conveyed on the secondary transfer belt (24). (50) can contact between rollers (16) and (22). Further, in the vicinity of the secondary transfer belt (24), a fixing belt (26) which is an endless belt stretched between a pair of rollers, and a pressure roller (pressed by the fixing belt (26)) ( 27) is provided. A sheet reversing device (28) for reversing the recording paper when an image is formed on both sides of the recording paper is disposed in the vicinity of the secondary transfer belt (24) and the fixing device (25).

  Next, a method for forming a full-color image using the image forming apparatus (100C) will be described. First, an automatic document feeder: a color document is set on the document table (130) of the ADF (400), or the automatic document feeder (400) is opened and placed on the contact glass (32) of the scanner (300). A color document is set, and the automatic document feeder (400) is closed. When a start switch (not shown) is pressed, when a document is set on the automatic document feeder (400), the document is transported and moved onto the contact glass (32). ) When a document is set on the scanner, the scanner (300) is immediately driven, and the first traveling body (33) including the light source and the second traveling body (34) including the mirror travel. At this time, after the reflected light from the original surface of the light irradiated from the first traveling body (33) is reflected by the second traveling body (34), the reading sensor (36) is passed through the imaging lens (35). By receiving the light, the original is read and image information of black, yellow, magenta and cyan is obtained.

The image information of each color is transmitted to the image forming unit (120) of each color, and a toner image of each color is formed. As shown in FIG. 4, each color image forming unit (120) includes a photosensitive drum (10), a charging roller (20) for uniformly charging the photosensitive drum (10), and image information for each color. Based on the above, an exposure device (30) for exposing the photosensitive drum (10) with the exposure light L to form an electrostatic latent image of each color, and developing the electrostatic latent image with a developer of each color to develop a toner image of each color. A developing device (40) for forming the toner image, a transfer roller (80) for transferring the toner image onto the intermediate transfer belt (50), a cleaning device (60) having a cleaning blade, and a static elimination lamp (70). Prepare.
The toner images of the respective colors formed by the image forming units (120) of the respective colors are sequentially transferred (primary transfer) onto the intermediate transfer body (50) which is stretched and moved by the rollers (14), (15) and (16). And superimposed to form a composite toner image.

  On the other hand, in the paper feed table (200), one of the paper feed rollers (142) is selectively rotated to feed recording paper from one of the paper feed cassettes (144) provided in multiple stages in the paper bank (143). The paper is separated one by one by the separation roller (145), sent to the paper feed path (146), transported by the transport roller (147), and guided to the paper feed path (148) in the copying machine main body (150). Stop against the roller (49). Alternatively, the paper feeding roller (51) is rotated to feed out the recording paper on the manual feed tray (54), and separated one by one by the separation roller (52) and guided to the manual paper feeding path (53). ) And stop. The registration roller (49) is generally used while being grounded, but may be used in a state where a bias is applied in order to remove paper dust from the recording paper. Next, by rotating the registration roller (49) in time with the composite toner image formed on the intermediate transfer belt (50), the intermediate transfer belt (50) and the secondary transfer belt (24) are rotated. The recording paper is sent out to transfer the composite toner image onto the recording paper (secondary transfer). The toner remaining on the intermediate transfer belt (50) to which the composite toner image has been transferred is removed by the cleaning device (90).

  The recording paper onto which the composite toner image has been transferred is conveyed by the secondary transfer belt (24), and then the composite toner image is fixed by the fixing device (25). Next, the recording paper is switched on the conveyance path by the switching claw (55), and is discharged onto the paper discharge tray (57) by the discharge roller (56). Alternatively, the conveyance path of the recording paper is switched by the switching claw (55), reversed by the sheet reversing device (28), and an image is similarly formed on the back surface, and then the ejection tray by the ejection roller (56). (57) It is discharged on the top.

  In the image forming method of the present invention, by using the carrier of the present invention, it is possible to provide a stable quality image over a long period of time with little occurrence of toner scattering, background stain, and color stain.

Examples of the present invention will be described below, but the present invention is not limited to the following examples.

<Reagents>
The sources and pretreatment methods of main reagents used for the preparation of carriers are described below. Isobutyltrimethoxysilane (IBTMS; manufactured by Chisso-Amax), 3-methacryloyltrimethoxysilane (S710; manufactured by Chisso-Amax), 2-isobutylbromide (Tokyo Chemical Industry), copper (I) chloride, pentamethyl Diethylenetriamine (PMDETA, manufactured by Tokyo Chemical Industry Co., Ltd.), tetrahydrofuran (THF, manufactured by Nacalai Tesque), methanol (manufactured by Nacalai Tesque), and concentrated sulfuric acid (manufactured by Nacalai Tesque) were all commercially available products. Triethylamine (manufactured by Nacalai Tesque) was used by distilling a commercially available product under a nitrogen stream. Toluene (manufactured by Nacalai Tesque) was used by distilling a commercially available product in the presence of calcium hydride in a nitrogen stream. Methyl methacrylate (MMA; manufactured by Nacalai Tesque) was used by distilling a commercially available product under reduced pressure in the presence of calcium hydride. Commercially available 2-hydroxyethyl methacrylate (HEMA; manufactured by Nacalai Tesque) was distilled under reduced pressure.

(Production Example 1)
<Preparation of binder resin 1>
-Preparation of SQA-1 (ATRP initiation group-substituted cage-type polysilsesquioxane)-
SQA-1 was synthesized by the following method.
A three-necked flask with a 2000 mL slide equipped with a reflux condenser with a ball, a three-way cock, a mechanical stirrer, and a thermometer was purged with nitrogen and placed under a nitrogen stream. Flask containing 18.8 mL of 1N aqueous sodium hydroxide, 132 g (0.530 mol) of S710 (3-methacryloyltrimethoxysilane), 94.9 g (0.530 mol) of isobutyltrimethoxysilane (IBTMS), and 1600 mL of tetrahydrofuran (THF) And reacted at 60 ° C. for 3 hours. After cooling to room temperature, 1.5 mL of concentrated sulfuric acid was added for neutralization. After removing the low boiling point portion with a rotary evaporator, the flask was returned to the original flask again, 1600 mL of methanol and 4 mL of concentrated sulfuric acid were added, and the mixture was stirred at room temperature for 24 hours to conduct a hydrolysis reaction of the 3-methacryloylpropyl group. After confirming the completion of hydrolysis by 1H-NMR, the reaction mixture was neutralized by adding a saturated aqueous solution of sodium bicarbonate. The low boiling point portion was removed with a rotary evaporator, followed by extraction with tetrahydrofuran, washing with saturated brine, and dehydration with anhydrous magnesium sulfate. The low boiling point portion was removed with a rotary evaporator to obtain the target hydroxy-substituted cage polysilsesquioxane (SQH-1). The yield was 80.0 g, and the yield was 68.6%.

  Next, a 1000 mL sliding three-necked flask equipped with a magnetic stir bar, three-way cock, 200 mL dropping funnel, septum cap, and thermometer was degassed, dried, and purged with argon. To this, 80.0 g (364 mmol as Si—OH equivalent) of the cage-type polysilsesquioxane SQH-1 previously synthesized, 40.4 g (400 mmol) of triethylamine (HBr absorbing solvent), and 500 mL of dry diethyl ether were added, Cooled to 0 ° C. or lower with dry ice-methanol. To this, 100 mL THF solution of 83.7 g (364 mL) of 2-isobutyl bromide was dropped over 15 minutes. After stirring at 0 ° C. for 1 hour, the mixture was stirred at room temperature for 18 hours. The ammonium salt was removed by vacuum filtration, the low boiling point was removed with a rotary evaporator, extracted with THF, washed with distilled water, and dehydrated with anhydrous magnesium sulfate. After filtration, the low boiling point portion was removed with a rotary evaporator to obtain the target product SQA-1 (ATRP initiation group-substituted cage polysilsesquioxane). The yield was 127 g, the yield was 94.9%, the number average molecular weight was 1930, and the mass average molecular weight was 2920. The spectrum of the obtained SQA-1 in 1H-NMR (deuterated chloroform, tetramethylsilane internal standard) measurement is 0.55-0.73 (4H), 0.90-1.00 (3H), 1.70. -1.90 (2H), 1.90-1.97 (7H), 4.1-4.2 (2H), and spectrum (peak) in 29Si-NMR (deuterated chloroform, tetramethylsilane internal standard) measurement ) Was -68.

-Production of binder resin 1-
A 500 mL three-necked flask equipped with a magnetic stir bar, Dimroth tube, three-way cock, septum, and thermometer was degassed, dried, and purged with argon. To this, 1.85 g (5.00 mmol; as a polymerization initiating group) of SQA-1, 47.5 g (475 mmol) of MMA, 3.25 g (25.0 mmol) of HEMA, and 0.248 g of copper (I) chloride (2.50 mmoL), 100 mL of toluene was added, and freeze degassing was repeated three times, followed by argon flow. It heated to 70 degreeC using the oil bath, stirring magnetically. After the temperature increase, 0.217 g (1.25 mmol) of PMDETA was added and reacted at 70 ° C. for 23.5 hours. The reaction solution turned dark green. After the reaction, toluene (100 mL) and silica gel # 60 (50 mL) were added, and the mixture was stirred at room temperature for 24 hours. At this point, the color of the solution changed to light yellow. Insoluble matter was filtered under reduced pressure using Hyflo Supercell (manufactured by Nacalai Tesque), and then diluted to 1 L with THF. When this THF solution was added to 6 L of hexane with vigorous stirring and reprecipitated, a colorless solid precipitated. The solid was collected by filtration under reduced pressure, and then dried to a constant weight with a vacuum dryer to obtain [Binder Resin 1]. The yield of [Binder Resin 1] was 16.0 g, the yield was 30.4%, the number average molecular weight was 17,000, the mass average molecular weight was 34000, and the polydispersity was 2.0, 1H-NMR (deuterated chloroform, tetramethyl The measurement results of the silane internal standard were 0.60-1.00, 1.60-2.00, 3.40-3.55, 3.6-4.1.

(Production Example 2)
<Preparation of binder resin 2>
A 2000-mL three-necked flask equipped with a magnetic stir bar, Dimroth tube, three-way cock, septum, and thermometer was degassed, dried, and purged with argon. To this, 10.0 g (27.0 mmol; as a polymerization initiating group) of SQA-1, MMA 123 g (123 mmol), HEMA 8.44 g (64.9 mmol), copper (I) chloride 1.34 g (13.5 mmol), toluene 500 mL was added and freeze deaeration was repeated three times, followed by an argon stream. It heated to 70 degreeC using the oil bath, stirring magnetically. After raising the temperature, 1.17 g (6.75 mmol) of PMDETA was added and reacted at 70 ° C. for 18 hours. The reaction solution turned dark green. After the reaction, 300 mL of toluene and 150 mL of silica gel # 60 were added and stirred at room temperature for 24 hours. At this point, the color of the solution changed to light yellow. Insoluble matters were filtered under reduced pressure using Hyflo Supercell (manufactured by Nacalai Tesque), and then diluted to 3 L with THF. When this THF solution was added to 6-fold volume of hexane with vigorous stirring and reprecipitated, a colorless solid precipitated. After filtration under reduced pressure, it was dried to a constant weight with a vacuum dryer to obtain [Binder Resin 2]. The yield of [Binder Resin 2] was 105.4 g, the yield was 74.4%, the number average molecular weight 15000, the mass average molecular weight 37000, the polydispersity 2.5, 1H-NMR (deuterium chloroform, tetramethylsilane internal Criteria) The measurement results were 0.60-1.00, 1.60-2.00, 3.40-3.55, 3.6-4.1.

(Production Example 3)
<Preparation of binder resin 3>
A 500 mL three-necked flask equipped with a magnetic stir bar, Dimroth tube, three-way cock, 100 mL dropping funnel, septum and thermometer was degassed, dried and purged with argon. To this, 1.85 g of SQA-1 (5.00 mmol; as a polymerization initiating group), 47.5 g (475 mmol) of MMA, 0.248 g (2.50 mmol) of copper (I) chloride, and 100 mL of toluene were added, followed by freeze degassing. Was repeated three times, and then under an argon stream. It heated to 70 degreeC using the oil bath, stirring magnetically. After the temperature increase, 0.217 g (1.25 mmol) of PMDETA was added and reacted at 70 ° C. The reaction solution turned dark green. Seven hours after the start of the reaction, 3.25 g (25.0 mmol) of HEMA was added thereto using a syringe, and the mixture was further reacted at 70 ° C. for 15.5 hours. After the reaction, 100 mL of toluene and 50 mL of silica gel # 60 were added and stirred at room temperature for 24 hours. At this point, the color of the solution changed to light yellow. Insoluble matter was filtered under reduced pressure using Hyflo Supercell (manufactured by Nacalai Tesque), and then diluted to 1 L with THF. When this THF solution was added to 6 L of hexane with vigorous stirring and reprecipitated, a colorless solid precipitated. After filtration under reduced pressure, the product was dried to a constant weight with a vacuum drier to obtain the target [Binder Resin 3]. The yield of [Binder Resin 3] was 23.2 g, the yield was 44.1%, the number average molecular weight 24000, the mass average molecular weight 34000, the polydispersity 1.4, 1H-NMR (deuterated chloroform, tetramethylsilane). Internal standard) The measurement results were 0.60-1.00, 1.60-2.00, 3.40-3.55, 3.6-4.1.

(Production Example 4)
<Preparation of binder resin 4>
A 500 mL sliding three-necked flask equipped with a magnetic stir bar, Dimroth tube, three-way cock, 100 mL dropping funnel, and septum was degassed, dried, and purged with argon. To this, 0.62 g (1.67 mmol; as a polymerization initiating group) of SQA-1, MMA 47.5 g (475 mmol), HEMA 3.25 g (25.0 mmol), copper (I) chloride 0.08 g (0.83 mmol) Toluene (100 mL) was added, and freeze degassing was repeated three times, and then under an argon stream. It heated to 70 degreeC using the oil bath, stirring magnetically. After the temperature increase, 0.072 g (0.42 mmol) of PMDETA was added and reacted at 70 ° C. for 23.5 hours. The reaction solution turned dark green. After the reaction, toluene (100 mL) and silica gel # 60 (50 mL) were added, and the mixture was stirred at room temperature for 24 hours. At this point, the color of the solution changed to light yellow. Insoluble matter was filtered under reduced pressure using Hyflo Supercell (manufactured by Nacalai Tesque), and then diluted to 1 L with THF. When this THF solution was added to 6 L of hexane with vigorous stirring and reprecipitated, a colorless solid precipitated. After filtration under reduced pressure, it was dried to a constant weight with a vacuum dryer to obtain [Binder Resin 4]. The yield of [Binder Resin 4] was 28.0 g, the yield was 52.7%, the number average molecular weight was 79000, the mass average molecular weight was 155000, and the polydispersity was 2.0, 1H-NMR (deuterium chloroform, tetramethylsilane internal The measured value of group) was 0.70-1.10, 1.70-2.05, 3.45-3.60, 3.7-4.2.

(Production Example 5)
<Preparation of binder resin 5>
A 500 mL three-necked flask equipped with a magnetic stir bar, Dimroth tube, three-way cock, 100 mL dropping funnel, septum and thermometer was degassed, dried and purged with argon. To this was added 1.85 g of SQA-1 (5.00 mmol; as a polymerization initiating group), 25.0 g (250 mmol) of MMA, 0.248 g (2.50 mmol) of copper (I) chloride, and 100 mL of toluene, followed by freeze degassing. Was repeated three times, and then under an argon stream. It heated to 70 degreeC using the oil bath, stirring magnetically. After the temperature increase, 0.217 g (1.25 mmol) of PMDETA was added and reacted at 70 ° C. The reaction solution turned dark green. Six hours after the start of the reaction, 3.25 g (25.0 mmol) of HEMA was added thereto using a syringe and further reacted at 70 ° C. for 3 hours. Next, 25.0 g (250 mmol) of MMA was added thereto and reacted at 70 ° C. for 18 hours. After the reaction, 100 mL of toluene and 50 mL of silica gel # 60 were added and stirred at room temperature for 24 hours. At this point, the color of the solution changed to light yellow. Insoluble matter was filtered under reduced pressure using Hyflo Supercell (manufactured by Nacalai Tesque), and then diluted to 1 L with THF. When this THF solution was added to 6 L of hexane with vigorous stirring and reprecipitated, a colorless solid precipitated. After filtration under reduced pressure, it was dried to a constant weight with a vacuum dryer to obtain [Binder Resin 5]. The yield of [Binder Resin 5] was 26.5 g, the yield was 49.9%, the number average molecular weight 22000, the mass average molecular weight 52000, the polydispersity 2.4, 1H-NMR (deuterium chloroform, tetramethylsilane internal The measurement results according to (standard) were 0.60-1.00, 1.60-2.00, 3.40-3.55, 3.6-4.1.

(Production Example 6)
<Preparation of binder resin 6>
A 2000-mL three-necked flask equipped with a magnetic stir bar, Dimroth tube, three-way cock, septum, and thermometer was degassed, dried, and purged with argon. To this, 60.0 g of SQA-1 (163 mmol; as a polymerization initiating group), 570 g (5.69 mol) of MMA, 30.0 g (0.231 mol) of HEMA, and 8.07 g (81) of copper (I) chloride 0.5 mmol) and toluene (1000 mL) were added, and freeze degassing was repeated three times, followed by argon flow. It heated to 70 degreeC using the oil bath, stirring magnetically. After the temperature increase, 14.1 g (81.5 mmol) of PMDETA was added and reacted for 3 hours. The reaction solution turned dark green. The reaction temperature once rose to 90 ° C and then returned to 70 ° C. After the reaction, the contents were divided into three equal portions in a 2 L Erlenmeyer flask, 1000 mL of toluene and 500 mL of silica gel # 60 were added to each, and the mixture was stirred at room temperature for 24 hours. At this point, the color of the solution changed to light yellow. Insoluble matter was filtered under reduced pressure using Hyflo Supercell (manufactured by Nacalai Tesque), and then diluted with THF to a total of 6 L. When this THF solution was added to 6-fold volume of hexane with vigorous stirring and reprecipitated, a colorless solid precipitated. After filtration under reduced pressure, it was dried to a constant weight with a vacuum drier to obtain the target [Binder Resin 6]. The yield of [Binder Resin 6] was 569 g, yield 95.0%, number average molecular weight 25,900, mass average molecular weight 102,000, polydispersity 3.9, 1H-NMR (deuterated chloroform, tetramethyl Silane internal reference) Spectra were 0.60-1.00, 1.60-2.00, 3.40-3.55, 3.6-4.1.

(Production Example 7)
<Preparation of Toner 1>
―Synthesis of organic fine particle emulsion―
In a reaction vessel in which a stir bar and a thermometer are set, 683 parts by mass of water, 11 parts by mass of sodium salt of ethylene oxide methacrylate adduct sulfate (Eleminol RS-30, manufactured by Sanyo Chemical Industries Ltd.), 83 parts by mass of styrene Part, 83 parts by weight of methacrylic acid, 110 parts by weight of butyl acrylate, and 1 part by weight of ammonium persulfate were added and stirred at 400 rpm for 15 minutes to obtain a white emulsion. This emulsion was heated to raise the system temperature to 75 ° C. and reacted for 5 hours. Next, 30 parts by mass of a 1% by mass ammonium persulfate aqueous solution was added, and the mixture was aged at 75 ° C. for 5 hours. An aqueous dispersion was obtained. This is designated as [fine particle dispersion 1].
The volume average particle diameter of the fine particles contained in the obtained [fine particle dispersion 1] was measured with a particle size distribution measuring apparatus (“LA-920”, manufactured by Horiba, Ltd.) using a laser scattering method, and found to be 105 nm. It was. Moreover, a part of [Fine Particle Dispersion 1] was dried to isolate only the resin content. The glass transition temperature (Tg) of this resin was 59 ° C., and the weight average molecular weight (Mw) was 150,000.

-Preparation of aqueous phase-
990 parts by weight of water, 83 parts by weight of [Fine Particle Dispersion 1], 37 parts by weight of 48.5% by weight aqueous solution of sodium dodecyl diphenyl ether disulfonate (Eleminol MON-7, Sanyo Chemical Industries, Ltd.), and 90 parts by weight of ethyl acetate Were mixed and stirred to obtain a milky white liquid. This liquid is referred to as [Aqueous Phase 1].

―Synthesis of low molecular weight polyester―
In a reaction vessel equipped with a cooling tube, a stirrer, and a nitrogen introduction tube, 229 parts by mass of bisphenol A ethylene oxide 2 mol adduct, 529 parts by mass of bisphenol A propylene oxide 3 mol adduct, 208 parts by mass of terephthalic acid, 46 adipic acid 46 Part by mass and 2 parts by mass of dibutyltin oxide were charged and reacted at 230 ° C. for 8 hours under normal pressure. Subsequently, after reacting under reduced pressure of 10 to 15 mmHg for 5 hours, 44 parts by mass of trimellitic anhydride was put in the reaction vessel and reacted at 180 ° C. and normal pressure for 2 hours to synthesize [low molecular weight polyester 1].
The obtained [low molecular polyester 1] has a glass transition temperature (Tg) of 45 ° C., a weight average molecular weight (Mw) of 5,800, a number average molecular weight of 2,600, and an acid value of 24 mgKOH / g.

―Synthesis of polyester prepolymer―
In a reaction vessel equipped with a cooling tube, a stirrer, and a nitrogen introduction tube, 682 parts by mass of bisphenol A ethylene oxide 2 mol adduct, 81 parts by mass of bisphenol A propylene oxide 2 mol adduct, 283 parts by mass of terephthalic acid, 22 parts by mass of merit acid and 2 parts by mass of dibutyltin oxide were added and reacted at 230 ° C. for 8 hours under normal pressure. Subsequently, it reacted for 5 hours under the reduced pressure of 10-15 mmHg, and the [intermediate polyester 1] was synthesize | combined.
The obtained [Intermediate polyester 1] had a number average molecular weight of 2,100, a weight average molecular weight of 9,500, a glass transition temperature (Tg) of 55 ° C., an acid value of 0.5 mgKOH / g, and a hydroxyl value of 51 mgKOH / g. .
Next, 410 parts by mass of [Intermediate Polyester 1], 89 parts by mass of isophorone diisocyanate, and 500 parts by mass of ethyl acetate are placed in a reaction vessel equipped with a cooling pipe, a stirrer, and a nitrogen introduction pipe. Reaction was performed for a while to obtain [Prepolymer 1].
The obtained [Prepolymer 1] had a free isocyanate mass% of 1.74%.

―Synthesis of ketimine―
In a reaction vessel equipped with a stir bar and a thermometer, 170 parts by mass of isophoronediamine and 75 parts by mass of methyl ethyl ketone were charged and reacted at 50 ° C. for 5 hours to synthesize [ketimine compound 1]. The amine value of the obtained [ketimine compound 1] was 418.

-Preparation of master batch (MB)-
1,200 parts by weight of water, carbon black (PBk-7: Printex 60, manufactured by Degussa, DBP oil absorption = 114 ml / 100 mg, pH = 10), 540 parts by weight, and polyester resin (manufactured by Sanyo Chemical Industries, RS801) 1 , 200 parts by mass were added and mixed with a Henschel mixer (Mitsui Mining Co., Ltd.). The obtained mixture was kneaded at 150 ° C. for 30 minutes using two rolls, cooled by rolling, and pulverized with a pulverizer to obtain a master batch. This is designated as [Masterbatch 1].

-Preparation of oil phase-
In a reaction vessel equipped with a stir bar and a thermometer, 300 parts by weight of [low molecular weight polyester 1], 90 parts by weight of carnauba wax, 10 parts by weight of rice wax, and 1000 parts by weight of ethyl acetate were charged and stirred while stirring. After dissolving at 0 ° C., it was rapidly cooled to 4 ° C. at once. Using a bead mill (Ultra Visco Mill, manufactured by Imex Co., Ltd.), the liquid feeding speed is 1 kg / hr, the disk peripheral speed is 6 m / sec, and 0.5 mm zirconia beads are filled by 80% by volume, and dispersion is performed under conditions of 3 passes. And a wax dispersion having a volume average particle size of 0.6 μm was obtained.
Next, 500 parts by weight of “Masterbatch 1” and 640 parts by weight of a 70% by weight ethyl acetate solution of “Low molecular weight polyester 1” were added, mixed for 10 hours, then 5 passes through the bead mill, and ethyl acetate was added to obtain a solid content. “Oil phase 1” adjusted to a concentration of 50% by mass was produced.

―Preparation of polymerized toner―
[Oil Phase 1] 73.2 parts by mass, [Prepolymer 1] 6.8 parts by mass, and [Ketimine Compound 1] 0.48 parts by mass were placed in a container and mixed well with [Emulsified oil phase 1]. 120 parts by mass of aqueous phase 1] was added, mixed for 1 minute with a homomixer, and then allowed to converge with a paddle for 1 hour with gentle stirring to obtain [Emulsion slurry 1].
The obtained [Emulsion slurry 1] was desolvated at 30 ° C. for 1 hour, further aged at 60 ° C. for 5 hours, washed with water, filtered and dried, and then sieved with a mesh of 75 μm, and the volume average particle diameter Toner base particles having a particle size of 6.1 μm, a number average particle size of 5.4 μm, and an average circularity of 0.972 were prepared.
Next, 0.7 parts by mass of hydrophobic silica and 0.3 parts by mass of hydrophobized titanium oxide were mixed with 100 parts by mass of the obtained toner base particles using a Henschel mixer to prepare “Toner 1”.

In the following Examples 1 to 12 and Comparative Examples 1 to 5, the particle diameter of the phosphorus-doped conductive tin oxide fine particles, the particle size distribution of the inorganic fine particles, the particle size distribution of the carrier, and the electric resistance of the carrier are measured as follows. did.
<Measurement of particle size distribution of phosphorus-doped conductive tin oxide fine particles and inorganic fine particles>
Nanotrac particle size distribution analyzer: UPA-EX150 (manufactured by Nikkiso Co., Ltd.) was used to measure the particle size distribution of phosphorus-doped conductive tin oxide fine particles and inorganic fine particles.
<Measurement of carrier particle size distribution>
Microtrac particle size distribution analyzer: The particle size distribution of the carrier was measured using a model HRA9320-X100 (manufactured by Nikkiso Co., Ltd.).
<Measurement of volume resistivity of carrier>
A cell containing two electrodes with a surface area of 2.5 cm x 4 cm separated by a distance of 0.2 cm is filled with a carrier and tapped 10 times with a drop height of 1 cm and a tapping speed of 30 times / minute. It was. Next, a resistance value r [Ω] 30 seconds after applying a DC voltage of 1000 V between the electrodes was measured using a high resistance meter 4329A (manufactured by Yokogawa Hewlett-Packard Co., Ltd.), and the formula R = Log [ r × (2.5 × 4) /0.2]
From this, the volume resistivity R [Log (Ω · cm)] was calculated.

<Preparation of carrier 1>
Binder resin 1 (Mw: 34000 polydispersity: 2.0) 92.4 parts by mass Block polyisocyanate (Mitsui Chemical Polyurethanes, Ltd. Takenate B-882N solid content mass 70%) 34.3 parts by mass Phosphorus dope Conductive tin oxide dispersion (Nissan Chemical Co., Ltd. CX-S204IP Solid content 20% by mass Volume average particle size: 20 nm) 420.0 parts by mass Alumina fine particles (Sumitomo Chemical Co., Ltd. Sumirakondam AA-05 Volume average particle Diameter: 0.5 μm) 36.0 parts by mass Aminosilane coupling agent (Toray Dow Corning Co., Ltd. SH6020 solid content 100% by mass) 3.6 parts by mass Toluene 747.0 parts by mass Dispersed for minutes to prepare a coating layer dispersion. Ferrite powder (saturation magnetic moment at 1 k gauss 65 emu / g) is used as the core material, and the coating layer dispersion is applied to the surface of the core material using a tumbling flow type coating device so that the film thickness becomes 1.0 μm. And dried. The obtained carrier was baked in an electric furnace at 170 ° C. for 1 hour. After cooling, the ferrite powder bulk was crushed using a sieve having an opening of 90 μm to obtain “Carrier 1”.
The obtained carrier 1 had a volume average particle diameter Dv of 39.4 μm, a number average particle diameter Dn of 35.2 μm, and Dv / Dn of 1.12. The volume resistivity of the carrier 1 was 11.33 [log (Ω · cm)], and the film thickness was 1.0 μm.

<Production of Carrier 2>
Binder resin 1 (Mw: 34000 polydispersity: 2.0) 103.2 parts by mass Phosphorus-doped conductive tin oxide dispersion (Nissan Chemical Industry Co., Ltd. CX-S204IP solid content 20% by mass Volume average particle diameter: 200.0) 360.0 parts by mass / alumina fine particles (Sumitomo Chemical Co., Ltd. Sumirakondam AA-04 volume average particle size: 0.4 μm) 60.0 parts by mass / aminosilane coupling agent (Toray Dow Corning Co., Ltd. SH6020 solid) 480 parts by mass / toluene 805.3 parts by mass Using the above materials, “Carrier 2” was produced in the same manner as in Example 1.
The obtained carrier 2 had a volume average particle diameter Dv of 39.7 μm, a number average particle diameter Dn of 35.3 μm, and Dv / Dn of 1.12. The volume resistivity of the carrier 2 was 12.26 [log (Ω · cm)], and the film thickness was 1.0 μm.

<Preparation of carrier 3>
Binder resin 2 (Mw: 37000, polydispersity: 2.5) 134.4 parts by mass Guanamin resin solution (Mitsui Cytec Co., Ltd. Mycoat 106 solid content 77% by mass) 37.4 parts by mass Phosphorus-doped conductivity Tin oxide dispersion (Nissan Chemical Co., Ltd. CX-S204IP solid content 20% by mass Volume average particle size: 20 nm) 360.0 parts by mass Aminosilane coupling agent (Toray Dow Corning Co., Ltd. SH6020 solid content 100% by mass ) 4.8 parts by mass / toluene 796.7 parts by mass “Carrier 3” was produced in the same manner as in Example 1 using the above materials.
The obtained carrier 3 had a volume average particle diameter Dv of 38.6 μm, a number average particle diameter Dn of 34.6 μm, and Dv / Dn of 1.12. The volume resistivity of the carrier 3 was 12.06 [log (Ω · cm)], and the film thickness was 1.0 μm.

<Preparation of carrier 4>
Binder resin 2 (Mw: 37000 polydispersity: 2.5) 108.0 parts by mass Phosphorus-doped conductive tin oxide dispersion (Nissan Chemical Industry Co., Ltd. CX-S204IP solid content 20% by mass Volume average particle diameter: 200.0) 360.0 parts by mass Alumina fine particles (Sumitomo Chemical Co., Ltd. Sumirakondam AA-02 volume average particle size: 0.2 μm) 60.0 parts by mass Toluene 805.3 parts by mass Example 1 using the above materials “Carrier 4” was produced in the same manner as described above.
The obtained carrier 4 had a volume average particle diameter Dv of 39.3 μm, a number average particle diameter Dn of 34.3 μm, and Dv / Dn of 1.15. The volume resistivity of the carrier 4 was 12.55 [log (Ω · cm)], and the film thickness was 1.0 μm.

<Preparation of carrier 5>
Binder resin 3 (Mw: 34000 polydispersity: 1.4) 111.6 parts by mass Guanamine resin solution (Mitsui Cytec Co., Ltd. Mycoat 106 solid content 77% by mass) 37.4 parts by mass Phosphorus-doped conductivity Tin oxide dispersion (Nissan Chemical Co., Ltd. CX-S204IP solid content 20% by mass Volume average particle size: 20 nm) 300.0 parts by mass Alumina fine particles (volume average particle size: 13 nm) 36.0 parts by mass Aminosilane cup Ringing agent (Toray Dow Corning Co., Ltd. SH6020 solid content 100% by mass) 3.6 parts by mass Toluene 844.7 parts by mass Using the above materials, “Carrier 5” was produced in the same manner as in Example 1. .
The obtained carrier 5 had a volume average particle diameter Dv of 39.3 μm, a number average particle diameter Dn of 34.5 μm, and Dv / Dn of 1.14. The volume resistivity of the carrier 5 was 12.47 [log (Ω · cm)], and the film thickness was 1.0 μm.

<Preparation of carrier 6>
Binder resin 3 (Mw: 34000 polydispersity: 1.4) 91.2 parts by mass Block polyisocyanate (Mitsui Chemicals Polyurethanes Takenate B-882N solid content 70%) 34.3 parts by mass Phosphorus dope Conductive tin oxide dispersion (Nissan Chemical Industry Co., Ltd. CX-S204IP Solid content 20% by mass Volume average particle size: 20 nm) 420.0 parts by mass Alumina fine particles (Sumitomo Chemical Co., Ltd. Sumirakondam AA-04 Volume average particle) Diameter: 0.4 μm) 36.0 parts by mass Aminosilane coupling agent (Toray Dow Corning Co., Ltd. SH6020 solid content 100% by mass) 4.8 parts by mass Toluene 747.0 parts by mass Examples using the above materials “Carrier 6” was prepared in the same manner as in Example 1.
The obtained carrier 6 had a volume average particle diameter Dv of 38.9 μm, a number average particle diameter Dn of 34.5 μm, and Dv / Dn of 1.13. The volume resistivity of the carrier 6 was 11.43 [log (Ω · cm)], and the film thickness was 1.0 μm.

<Preparation of carrier 7>
Binder resin 4 (Mw: 155000 polydispersity: 2.0) 103.2 parts by mass Block polyisocyanate (Mitsui Chemical Polyurethanes, Ltd. Takenate B-882N solid content mass 70%) 41.1 parts by mass Phosphorus dope Conductive tin oxide dispersion (Nissan Chemical Industry Co., Ltd. CX-S204IP Solid content 20% by mass Volume average particle size: 20 nm) 360.0 parts by mass Alumina fine particles (volume average particle size: 1.2 μm) 36.0 mass Part / Toluene 793.0 parts by mass “Carrier 7” was produced in the same manner as in Example 1 using the above materials.
The obtained carrier 7 had a volume average particle diameter Dv of 38.2 μm, a number average particle diameter Dn of 34.1 μm, and Dv / Dn of 1.12. The volume resistivity of the carrier 7 was 12.31 [log (Ω · cm)], and the film thickness was 1.0 μm.

<Preparation of carrier 8>
Binder resin 4 (Mw: 155000 polydispersity: 2.0) 111.6 parts by mass Guanamine resin solution (Mitsui Cytec Co., Ltd. Mycoat 106 solid content 77% by mass) 37.4 parts by mass Phosphorus-doped conductivity Tin oxide dispersion (Nissan Chemical Industry Co., Ltd. CX-S204IP Solid content 20% by mass Volume average particle size: 20 nm) 300.0 parts by mass Alumina fine particles (Sumitomo Chemical Co., Ltd. Sumirakondam AA-02 Volume average particle size: 0.2 μm) 36.0 parts by mass. Aminosilane coupling agent (Toray Dow Corning Co., Ltd. SH6020 solid content 100% by mass) 3.6 parts by mass. Toluene 844.7 parts by mass. “Carrier 8” was produced in the same manner.
The obtained carrier 8 had a volume average particle diameter Dv of 38.7 μm, a number average particle diameter Dn of 34.7 μm, and Dv / Dn of 1.12. The volume resistivity of the carrier 8 was 12.40 [log (Ω · cm)], and the film thickness was 1.0 μm.

<Preparation of carrier 9>
Binder resin 5 (Mw: 52000 polydispersity: 2.4) 103.2 parts by mass Phosphorus-doped conductive tin oxide dispersion (Nissan Chemical Co., Ltd. CX-S204IP solid content 20% by mass Volume average particle diameter: 200.0) 360.0 parts by mass Alumina fine particles (volume average particle size: 13 nm) 60.0 parts by mass Aminosilane coupling agent (Toray Dow Corning SH6020 solid content 100% by mass) 4.8 parts by mass Toluene 805.3 parts by mass “Carrier 9” was produced in the same manner as in Example 1 using the above material.
The obtained carrier 9 had a volume average particle diameter Dv of 39.7 μm, a number average particle diameter Dn of 35.3 μm, and Dv / Dn of 1.12. The volume resistivity of the carrier 9 was 12.61 [log (Ω · cm)], and the film thickness was 1.0 μm.

<Preparation of carrier 10>
Binder resin 5 (Mw: 52000 polydispersity: 2.4) 96.0 parts by mass Block polyisocyanate (Mitsui Chemical Polyurethanes, Ltd. Takenate B-882N solid content mass 70%) 34.3 parts by mass Phosphorus dope Conductive tin oxide dispersion (Nissan Chemical Industry Co., Ltd. CX-S204IP Solid content 20% by mass Volume average particle size: 20 nm) 420.0 parts by mass Alumina fine particles (Sumitomo Chemical Co., Ltd. Sumirakondam AA-05 Volume average particle (Diameter: 0.5 μm) 36.0 parts by mass / toluene 747.0 parts by mass “Carrier 10” was produced in the same manner as in Example 1 using the above materials.
The obtained carrier 10 had a volume average particle diameter Dv of 39.5 μm, a number average particle diameter Dn of 34.2 μm, and Dv / Dn of 1.15. The volume resistivity of the carrier 10 was 11.48 [log (Ω · cm)], and the film thickness was 1.0 μm.

<Preparation of carrier 11>
Binder resin 6 (Mw: 102000 polydispersity: 3.9) 104.4 parts by mass Phosphorus-doped conductive tin oxide dispersion (Nissan Chemical Co., Ltd. CX-S204IP solid content 20% by mass Volume average particle diameter: 200.0) 360.0 parts by mass / alumina fine particles (Sumitomo Chemical Co., Ltd. Sumirakondam AA-04 volume average particle size: 0.4 μm) 60.0 parts by mass / aminosilane coupling agent (Toray Dow Corning Co., Ltd. SH6020 solid) Min. 100% by mass) 3.6 parts by mass / toluene 805.3 parts by mass “Carrier 11” was produced in the same manner as in Example 1 using the above materials.
The obtained carrier 11 had a volume average particle diameter Dv of 38.8 μm, a number average particle diameter Dn of 34.8 μm, and Dv / Dn of 1.11. The volume resistivity of the carrier 11 was 12.11 [log (Ω · cm)], and the film thickness was 1.0 μm.

<Preparation of carrier 12>
Binder resin 6 (Mw: 102000 polydispersity: 3.9) 139.2 parts by mass Guanamine resin solution (Mitsui Cytec Co., Ltd. Mycoat 106 solid content 77% by mass) 37.4 parts by mass Phosphorus-doped conductivity Tin oxide dispersion (Nissan Chemical Co., Ltd. CX-S204IP Solid content 20% by mass Volume average particle size: 20 nm) 360.0 parts by mass Toluene 796.7 parts by mass The same method as in Example 1 using the above materials Thus, “Carrier 12” was produced.
The obtained carrier 12 had a volume average particle diameter Dv of 38.7 μm, a number average particle diameter Dn of 34.3 μm, and Dv / Dn of 1.13. The volume resistivity of the carrier 12 was 12.32 [log (Ω · cm)], and the film thickness was 1.0 μm.

(Comparative Example 1)
<Production of Comparative Carrier 1>
-Acrylic resin (copolymer of methyl methacrylate 60 wt%, butyl acrylate 34 wt%, 2-hydroxyethyl acrylate 6 wt% Mw: 55000, polydispersity: 4.4) 89.9 parts by mass-Guanamine resin solution ( Mitsui Cytec Co., Ltd. Mycoat 106 Solid content 77% by mass) 50.0 parts by mass, phosphorus-doped conductive tin oxide coated alumina fine particles (volume average particle size: 300 nm) 72.0 parts by mass, alumina fine particles (Sumitomo Chemical Co., Ltd.) ) Sumirakondam AA-04 Volume average particle size: 0.4 μm) 36.0 parts by mass Aminosilane coupling agent (Toray Dow Corning Co., Ltd. SH6020 solid content 100% by mass) 3.6 parts by mass Toluene 1081.8 parts by mass Part “Comparative carrier 1” was produced in the same manner as in Example 1 using the above materials.
The obtained Comparative Carrier 1 had a volume average particle diameter Dv of 39.1 μm, a number average particle diameter Dn of 34.1 μm, and Dv / Dn of 1.15. Further, the volume resistivity of the comparative carrier 1 was 14.35 [log (Ω · cm)], and the film thickness was 1.0 μm.

(Comparative Example 2)
<Production of Comparative Carrier 2>
・ Silicone resin solution (Toray Dow Corning Co., Ltd. SR2405 solid content 50 mass%) 326.4 mass parts ・ ATO fine particle dispersion (volume average particle size: 30 nm solid content 20 mass%) 360.0 mass parts ・ Aminosilane cup Ring agent (Toray Dow Corning Co., Ltd. SH6020 solid content 100% by mass) 4.8 parts by mass, toluene 642.1 parts by mass “Comparative Carrier 2” was prepared in the same manner as in Example 1 using the above materials. did.
The obtained Comparative Carrier 2 had a volume average particle diameter Dv of 39.3 μm, a number average particle diameter Dn of 34.3 μm, and Dv / Dn of 1.15. Moreover, the volume resistivity of the comparison carrier 2 was 12.27 [log (Ω · cm)], and the film thickness was 1.0 μm.

(Comparative Example 3)
<Production of Comparative Carrier 3>
-Acrylic resin (Methyl methacrylate 60 wt%, butyl acrylate 34 wt%, 2-hydroxyethyl acrylate 6 wt% copolymer Mw: 55000, polydispersity: 4.4) 99.0 parts by mass-Guanamine resin solution ( Mitsui Cytec Co., Ltd. Mycoat 106 solid content 77% by mass) 17.1 parts by mass Silicone resin solution (Toray Dow Corning Co., Ltd. SR2405 solid content 50% by mass) 158.4 parts by mass Phosphorus-doped conductive tin oxide dispersion Body (Nissan Chemical Co., Ltd.) CX-S204IP Solid content 20% by mass Volume average particle size: 20 nm 360.0 parts by mass Alumina fine particles (Sumitomo Chemical Co., Ltd. Sumirakondam AA-02 Volume average particle size: 0.2 μm ) 36.0 parts by mass / toluene 662.8 parts by mass By the same method as in Example 1 using the above materials, Yaria 3 "was produced.
The obtained Comparative Carrier 3 had a volume average particle diameter Dv of 38.7 μm, a number average particle diameter Dn of 34.6 μm, and Dv / Dn of 1.12. The volume resistivity of the comparative carrier 3 was 12.22 [log (Ω · cm)], and the film thickness was 1.0 μm.

(Comparative Example 4)
<Production of Comparative Carrier 4>
Silicone graft acrylic resin solution (Shin-Etsu Chemical Co., Ltd. X-22-8004 solid content 40% by mass) 210.0 parts by mass Guanamine resin solution (Mitsui Cytec Co., Ltd. Mycoat 106 solid content 77% by mass) 8 parts by mass, phosphorus-doped conductive tin oxide-coated alumina fine particles (volume average particle size: 300 nm) 72.0 parts by mass, alumina fine particles (Sumitomo Chemical Co., Ltd. Sumirakondam AA-05 volume average particle size: 0.5 μm) 0 part by mass / toluene 956.6 parts by mass “Comparative carrier 4” was produced in the same manner as in Example 1 using the above materials.
The obtained Comparative Carrier 4 had a volume average particle diameter Dv of 38.9 μm, a number average particle diameter Dn of 34.1 μm, and Dv / Dn of 1.14. Further, the volume resistivity of the comparative carrier 4 was 15.02 [log (Ω · cm)], and the film thickness was 1.0 μm.

(Comparative Example 5)
<Production of Comparative Carrier 5>
-Binder resin 5 (Mw: 52000 polydispersity: 2.4) 99.6 parts by mass-Block polyisocyanate (Mitsui Chemical Polyurethanes, Ltd. Takenate B-882N solid content mass 70%) 41.1 parts by mass Conductive tin oxide coated alumina fine particles (volume average particle size: 300 nm) 72.0 parts by mass Alumina fine particles (Sumitomo Chemical Industries, Ltd. Sumirakondam AA-04 volume average particle size: 0.4 μm) 36.0 parts by mass aminosilane Coupling agent (Toray Dow Corning Co., Ltd. SH6020 solid content 100% by mass) 3.6 parts by mass Toluene 1081.0 parts by mass “Comparative Carrier 5” was prepared in the same manner as in Example 1 using the above materials. Produced.
The obtained Comparative Carrier 5 had a volume average particle diameter Dv of 39.2 μm, a number average particle diameter Dn of 35.1 μm, and Dv / Dn of 1.12. The volume resistivity of the comparative carrier 5 was 14.56 [log (Ω · cm)], and the film thickness was 1.0 μm.

  Table 1 shows the characteristics of the carriers produced in Examples 1 to 12 and Comparative Examples 1 to 5.

<Production of developer>
The produced carriers 1 to 12 and the comparative carriers 1 to 5 and the toner 1 were adjusted at a ratio such that the carrier coverage with the toner was 50%, and stirred with a tumbler mixer. To 12 and Comparative Examples 1 to 5 were prepared.

  Using the produced developer, the carrier coating layer was scraped and peeled off, toner spent, image density, image orientation, toner scattering, background stain, color stain, and comprehensive evaluation were performed as follows. It was. The results are shown in Table 2.

<Evaluation of carrier coating layer scraping and peeling>
Using a tandem type color image forming device (image Neo Neo450, manufactured by Ricoh Co., Ltd.), 200,000 running evaluations are performed, and the volume resistivity ratio of the carrier before and after running is evaluated in four stages based on the following criteria. did.
The volume resistivity change (decrease) evaluated here is caused by the carrier coating layer being scraped or peeled off due to stress during running evaluation. The degree of shaving and peeling of the coating layer can be evaluated.
〔Evaluation criteria〕
A: Ratio of volume resistivity after 200,000 sheets run / initial volume resistivity is 1/10 or more and 1 or less ○: Ratio of volume resistivity after 200,000 sheets run / initial volume resistivity is 1/100 or more Less than 1/10 Δ: Ratio of volume resistivity after 200,000 sheets run / initial volume resistivity is 1/1000 or more and less than 1/100 ×: Volume resistivity after 200,000 sheets run / initial volume resistivity The volume resistivity of the carrier referred to here is the volume measured in the same manner as above except that the carrier obtained by removing the toner from the developer using a blow-off device was used. Resistivity.

<Evaluation of toner spent property>
Using a tandem color image forming apparatus (imagio Neo450, manufactured by Ricoh Co., Ltd.), a chart with a 20% image area is controlled by controlling the toner density so that the image density becomes 1.4 ± 0.2, and 200,000. The amount of change in the developer charge amount (μc / g) after sheet output (charge amount decrease after 200,000 sheet run / charge amount at the initial stage of the run), compared to the initial value before output, the following criteria It was evaluated with. The charge amount was measured by a blow-off method.
〔Evaluation criteria〕
A: Less than 15% B: 15% or more and less than 30% Δ: 30% or more and less than 50% x: 50% or more.

  As the toner spends on the carrier, the composition on the outermost surface of the carrier changes, and the charge amount decreases. It is determined that the smaller the change in the charge amount before and after the run, the less the toner spent on the carrier.

<Image density evaluation>
Using a tandem type color image forming apparatus (image Neo 450, manufactured by Ricoh Co., Ltd.), the amount of each developer adhered to copy paper (TYPE6000 <70W>, manufactured by Ricoh Co., Ltd.) is 1.00 ± 0.05 mg. A solid image of / cm 2 was formed. The solid image was repeatedly formed on 1 million copies of the copy paper.
The image density of the obtained solid image was visually observed for the initial stage and after endurance of 200,000 sheets, and evaluated in four stages based on the following criteria. Note that the higher the image density obtained, the higher the density image can be formed. This evaluation corresponds to an embodiment of the image forming method of the present invention.
〔Evaluation criteria〕
A: Image density did not change at the initial stage and after endurance of 200,000 sheets, and high image quality was obtained. O: Image density decreased slightly after endurance of 200,000 sheets, but high image quality was obtained. Δ: 20 Image density decreased and image quality decreased after endurance of 10,000 sheets x: Image density decreased significantly and image quality significantly decreased after endurance of 200,000 sheets

<Evaluation of directionality of image>
An image chart in which halftone portions (1 cm × 1 cm) of image density = 0.2, 0.8 by a Macbeth reflection densitometer are arranged at regular intervals in the sheet passing direction is displayed as a tandem color image forming apparatus (image Neo Neo 450, (Ricoh Co., Ltd.) was used, and the degree of density reduction at the rear end of the halftone part was visually evaluated in four stages based on the following criteria.
〔Evaluation criteria〕
◎: There is no density difference at the rear end of the halftone part and it is in a good state. ○: There is almost no density difference at the rear end of the halftone part and it is in a good state. Δ: Density difference at the rear end of the halftone part. There is a level that is practical, but ×: the density difference at the rear end of the halftone part is so severe that it is not practical.

<Toner scattering evaluation>
The degree of toner contamination in the machine when 200,000 sheets of a 5% image area ratio chart is continuously output using a tandem color image forming apparatus (imagio Neo 450, manufactured by Ricoh Co., Ltd.) is as follows. Based on the above, it was evaluated in four stages.
〔Evaluation criteria〕
A: There is no toner contamination in the machine and it is in a good state. ○: There is no toner contamination in the machine and it is in a good state. Δ: There is toner contamination in the machine, but it is a practically usable level. Toner contamination is severe and unusable

<Evaluation of dirt>
By visually observing the degree of background contamination of the image background portion when 200,000 sheets of a 5% image area ratio chart were continuously output using a tandem color image forming apparatus (imagio Neo 450, manufactured by Ricoh Co., Ltd.), Based on the criteria, it was evaluated in three stages.
〔Evaluation criteria〕
○: No background stain on the image background Δ: Some background stain on the image background ×: Background stain on the image background

<Color stain evaluation>
A chart with an image area ratio of 0.5% is output continuously for 30,000 sheets using a tandem type color image forming apparatus (imagio Neo 450, manufactured by Ricoh Co., Ltd.), and then a yellow single color image is output. The image density of the yellow monochrome image after sheet output was measured by X-RITE 938 (manufactured by x-rite). The CIE L *, CIE a *, and CIE b * at the point where the yellow image density is 1.4 ± 0.5 are measured at three points to obtain an average value, and are substituted into the following formula to calculate the ΔE value. Based on the criteria, it was evaluated in three stages.

〔評価基準〕
○：ΔＥが２未満で色汚れがない
△：ΔＥが２以上４未満で色汚れが目立たず、色調変化は指摘されない
×：ΔＥが４以上で明らかに色汚れが目立ち、色調変化を指摘される

〔Evaluation criteria〕
○: ΔE is less than 2 and there is no color stain Δ: ΔE is 2 or more and less than 4 and color stain is inconspicuous and color tone change is not pointed out x: ΔE is 4 or more and color stain is clearly noticeable and color tone change is pointed out Ru

<Comprehensive evaluation>
From the above evaluation results, comprehensive judgment was made, and the following criteria were used for evaluation.
〔Evaluation criteria〕
◎: Very good ○: Good △: Bad x: Extremely bad

表２より、キャリア１〜１２を用いた実施例１〜１２の現像剤は、比較例１〜５の現像剤と比較して、色汚れを抑制し、画像の方向性を抑制し、高画像濃度が得られることがわかる。さらに、キャリアの被覆層の削れや剥離、トナースペント、トナー飛散や地汚れについても抑制できることがわかる。

From Table 2, the developers of Examples 1 to 12 using the carriers 1 to 12 suppress the color stains, suppress the directionality of the image, and the high image compared with the developers of Comparative Examples 1 to 5. It can be seen that the concentration is obtained. Further, it can be seen that the coating layer of the carrier can be prevented from being scraped or peeled off, toner spent, toner scattering, and soiling.

(Figure 1)
31 Cell 32a Electrode 32b Electrode 33 Carrier (FIGS. 2, 3, and 4)
DESCRIPTION OF SYMBOLS 10 Photosensitive drum 14 Roller 15 Roller 16 Roller 20 Charging roller 22 Roller 23 Roller 24 Secondary transfer belt 25 Fixing device 26 Fixing belt 27 Pressure roller 28 Sheet reversing device 30 Exposure device 32 Contact glass 33 First traveling body 34 Second Traveling body 35 Imaging lens 40 Developing device 41 Developing belt 42 (K, Y, M, C) Developing unit 43 (K, Y, M, C) Developing unit 44 (K, Y, M, C) Developing unit 45 ( K, Y, M, C) Developing unit 49 Registration roller 50 Intermediate transfer belt 51 Roller 53 Manual feed path 55 Switching claw 56 Discharge roller 57 Discharge tray 58 Corona charging device 60 Cleaning device 70 Static elimination lamp 80 Transfer roller 90 Cleaning device 95 Transfer paper 100A, B, C Image forming apparatus 120 (K, Y, M, C) The image forming unit 130 platen 142 paper feed roller 143 paper bank 144 sheet cassette 145 separating roller 146 feed path 147 transport rollers 148 feed path 150 copier body 200 feeder table 300 Scanner 400 automatic document feeder (ADF)
P Recording paper

JP 2006-058811 A Japanese Patent No. 3808120 Japanese Patent No. 39731313 JP 2006-163368 A JP 2007-240615 A Japanese Patent No. 3904174 JP 2007-248614 A JP 2005-320519 A JP 2002-80523 A J. et al. Am. Chem. Soc. 1994, 116, P7943 Macromolecules, 1994, 27, P7228 Chem. Rev. 2001, Volume 101, P2921

Claims (13)

A carrier in which the surface of core material particles made of a magnetic material is coated with a coating layer containing at least a binder resin and conductive fine particles, the binder resin comprising one or more polymerizable vinyl monomers as structural units Segment (A), a partially-slept structure of a cage silsesquioxane represented by the following general formula (1), and / or a cage silsesquioxane represented by the following general formula (2) A segment (B) including a partially-cleavage structure as a structural unit, wherein the conductive fine particles are phosphorus-doped conductive tin oxide fine particles composed of single particles of tin oxide doped with phosphorus. A carrier for electrophotography.

(However, n represents an integer of 4 or more, and the substituent R is a hydrogen atom, a halogen atom, an alkoxy group having 1 to 10 carbon atoms or an allyloxy group, a saturated hydrocarbon group having 1 to 20 carbon atoms, or 2 to 2 carbon atoms. It represents any of 20 alkenyl groups, 6 to 20 carbon atoms aralkyl groups, 7 to 20 carbon atoms aryl groups, and 1 to 10 silicon atom-containing groups.)

(However, n and m represent an integer greater than or equal to 2, respectively, and substituent R1, R2 is respectively independently a hydrogen atom, a halogen atom, a C1-C10 alkoxy group, or an allyloxy group, C1-C20. It represents any of a saturated hydrocarbon group, an alkenyl group having 2 to 20 carbon atoms, an aralkyl group having 6 to 20 carbon atoms, an aryl group having 7 to 20 carbon atoms, and a silicon atom-containing group having 1 to 10 silicon atoms. )   2. The electrophotography according to claim 1, wherein the first binder resin has a polydispersity calculated from a styrene equivalent molecular weight distribution determined by GPC (gel permeation chromatography) of 3.0 or less. For carrier.   The electrophotographic carrier according to any one of claims 1 to 2, wherein the binder resin has a mass average molecular weight Mw in the range of 20,000 to 200,000.   The carrier for electrophotography according to any one of claims 1 to 3, wherein the segment (A) contains a copolymer of one or more polymerizable vinyl monomers having at least a hydroxyl group.   The electrophotographic carrier according to any one of claims 1 to 4, wherein the segment (A) has an acrylic resin segment, and the acrylic resin segment is crosslinked with an amino resin or an isocyanate. .   6. The electrophotographic apparatus according to claim 1, wherein the binder resin has the segment (A) formed by living radical polymerization using the segment (B) as a polymerization initiator. Career.   The electrophotographic carrier according to claim 1, wherein the segment (A) is obtained by polymerizing a polymerizable vinyl monomer by an atom transfer radical polymerization method.   The electrophotographic carrier according to claim 1, wherein the coating layer contains inorganic fine particles, and the volume average particle diameter of the inorganic fine particles is 100 nm or more and 1 μm or less.   9. The electrophotographic carrier according to claim 1, wherein the coating layer further contains an aminosilane coupling agent.   The volume resistivity when a DC voltage of 1000 V is applied to the electrophotographic carrier is 10 [log (Ω · cm)] or more and 16 [log (Ω · cm)] or less. 10. The carrier for electrophotography according to any one of 9 above. 11. The electrophotographic carrier according to claim 1, wherein the electrophotographic carrier has a volume average particle diameter of 20 μm or more and 65 μm or less. An electrophotographic two-component developer comprising: the electrophotographic carrier according to claim 1; and a toner. An electrostatic latent image forming step for forming an electrostatic latent image on the electrostatic latent image carrier, and development for developing the electrostatic latent image using the developer according to claim 12 to form a visible image. An image forming method comprising: a step, a transfer step of transferring the visible image to a recording medium, and a fixing step of fixing the transfer image transferred to the recording medium.

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