JP2005115062A

JP2005115062A - Image carrier in image forming apparatus

Info

Publication number: JP2005115062A
Application number: JP2003349517A
Authority: JP
Inventors: Shinichi Kamoshita; 鴨志田伸一; Takeshi Ikuma; 井熊健
Original assignee: Seiko Epson Corp
Current assignee: Seiko Epson Corp
Priority date: 2003-10-08
Filing date: 2003-10-08
Publication date: 2005-04-28

Abstract

<P>PROBLEM TO BE SOLVED: To provide an image carrier for more reliably performing image formation over a prolonged period of time by stably performing charging by charge injection over a prolonged period of time. <P>SOLUTION: The image carrier 1 has a conductive substrate 2, an under coated layer 3 is formed on the substrate 2, and a photosensitive layer 4 which is a laminate of a charge generation layer 5 and a charge transport layer 6 is formed on the under coated layer 3. In the charge transport layer 6, a large number of conductive fine particles 7 are independently dispersed in the peripheral direction and in the thickness direction in such a way that a content of the conductive fine particles 7 is made higher on the surface side of the charge transport layer 6 and lower on the substrate 2 side of the charge transport layer 6. Thus, charging by charge injection can stably be performed over a prolonged period of time. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

本発明は、電子写真、ファクシミリ等の画像形成装置に用いられ、潜像が形成される像担持体の技術分野に関し、特に、光書込による潜像形成を行うための感光層を有するとともに、電荷注入による帯電を行うための多数の導電性微粒子を有する像担持体の技術分野に関する。 The present invention relates to a technical field of an image carrier that is used in an image forming apparatus such as an electrophotography and a facsimile and forms a latent image, and in particular, has a photosensitive layer for forming a latent image by optical writing, The present invention relates to a technical field of an image carrier having a large number of conductive fine particles for charging by charge injection.

静電潜像が形成される像担持体に電荷を注入することにより像担持体を帯電させる画像形成装置が提案されている（例えば、特許文献１参照）。この特許文献１に開示されている画像形成装置は像担持体である感光体ドラムを備えている。この感光体ドラムは、受光により電荷を発生する電荷発生層と発生した電荷を輸送する電荷輸送層とからなる光導電層と、電荷輸送層の上に、ホスファゼン樹脂からなるバインダー樹脂中に多数の導電性微粒子であるＳｎＯ₂からなる導電性フィラーを分散させて所定膜厚に形成された電荷注入層とを有している。そして、電荷注入層に接触帯電部材を接触させて接触帯電部材から電荷注入層のＳｎＯ₂に電荷を注入することにより感光体ドラムが一様帯電される。次いで、この感光体ドラムがレーザ光で露光されることにより、電荷発生層が受光して電荷を発生し、発生した電荷のうちプラス電荷が電荷輸送層により感光体ドラムの表面に輸送されることで、感光体ドラムの表面の露光部分が除電されて潜像が形成される。 There has been proposed an image forming apparatus that charges an image carrier by injecting electric charges into the image carrier on which an electrostatic latent image is formed (see, for example, Patent Document 1). The image forming apparatus disclosed in Patent Document 1 includes a photosensitive drum that is an image carrier. The photosensitive drum includes a photoconductive layer composed of a charge generation layer that generates charges by receiving light and a charge transport layer that transports the generated charges, and a binder resin composed of phosphazene resin on the charge transport layer. And a charge injection layer formed to have a predetermined thickness by dispersing conductive filler made of SnO ₂ which is conductive fine particles. The photosensitive drum is uniformly charged by bringing the contact charging member into contact with the charge injection layer and injecting charge from the contact charging member into SnO _{2 of the} charge injection layer. Next, the photoconductive drum is exposed to a laser beam so that the charge generation layer receives light and generates a charge, and the positive charge among the generated charges is transported to the surface of the photoconductive drum by the charge transport layer. Thus, the exposed portion of the surface of the photosensitive drum is neutralized to form a latent image.

このように電荷注入方式で感光体ドラムを帯電することで、低電圧で帯電を行うことができるため、電源のコストが安くなるとともにオゾン生成物の発生を防止することができる。更に、低電圧での帯電により、感光体ドラムにピンホール等がある場合、リークによる画像形成不良を極力抑えることが可能となる。
特開平６−３９２１号公報。 By charging the photosensitive drum by the charge injection method in this way, charging can be performed at a low voltage, so that the cost of the power source can be reduced and generation of ozone products can be prevented. Furthermore, when there is a pinhole or the like in the photosensitive drum due to charging at a low voltage, it is possible to suppress image formation defects due to leakage as much as possible.
Japanese Patent Laid-Open No. 6-3921.

ところで、前述の特許文献１に開示の感光体ドラムにおいては、例えば画像形成が長期にわたって行われることなどで、感光体ドラムの表層がこれに当接する部材により摩耗するようになる。しかしながら、前述の特許文献１に開示の感光体ドラムでは、感光体の表層にのみ電荷注入層を有する構成であるため、感光体ドラムの表層である電荷注入層が摩耗するようになる。そして、電荷注入層が摩耗してなくなると、電荷注入による帯電ができなく、画像形成を行うことができなくなる。換言すると、感光体ドラムの表層である電荷注入層の膜厚が画像形成装置の寿命の律速になるため、感光体ドラムの帯電を長期にわたって安定して行うことが難しい。 By the way, in the photosensitive drum disclosed in Patent Document 1, the surface layer of the photosensitive drum is worn by a member in contact with the photosensitive drum, for example, when image formation is performed over a long period of time. However, since the photoreceptor drum disclosed in Patent Document 1 has a charge injection layer only on the surface layer of the photoreceptor, the charge injection layer that is the surface layer of the photoreceptor drum becomes worn. When the charge injection layer is not worn, charging by charge injection cannot be performed and image formation cannot be performed. In other words, since the film thickness of the charge injection layer, which is the surface layer of the photosensitive drum, becomes the rate-determining factor of the life of the image forming apparatus, it is difficult to stably charge the photosensitive drum for a long period of time.

また、感光体ドラムの長期使用等によってこの感光体ドラムの表面に、トナーの樹脂成分の被覆等によりフィルミングが生じると、電荷注入層に対する電荷注入による帯電が確実に行うことができなくなる。そのため、像担持体の表層、つまり電荷注入層を積極的に研磨してこのフィルミングを除去しながら画像形成を行う必要がある。しかし、電荷注入層を研磨すると、前述の電荷注入層の摩耗の場合と同様に電荷注入層の膜厚が画像形成装置の寿命の律速となり、感光体ドラムの帯電を長期にわたって安定して行うことが難しくなる。 Further, if filming occurs on the surface of the photosensitive drum due to, for example, long-term use of the photosensitive drum due to coating of the resin component of the toner, charging by charge injection to the charge injection layer cannot be reliably performed. Therefore, it is necessary to form an image while removing the filming by actively polishing the surface layer of the image carrier, that is, the charge injection layer. However, when the charge injection layer is polished, the thickness of the charge injection layer becomes the rate-determining factor of the life of the image forming apparatus as in the case of the wear of the charge injection layer described above, and the photosensitive drum can be stably charged over a long period of time. Becomes difficult.

本発明は、このような事情に鑑みてなされたものであって、その目的は、電荷注入による帯電を長期にわたって安定して行うことで、画像形成を長期的にかつより確実に行うことのできる画像形成装置における像担持体を提供することである。 The present invention has been made in view of such circumstances, and an object of the present invention is to stably perform charging by charge injection over a long period of time so that image formation can be performed for a long period of time and more reliably. An object is to provide an image carrier in an image forming apparatus.

前述の課題を解決するために、請求項１の発明は、画像形成装置に用いられ、導電性の基材の上に電荷発生層と電荷輸送層とが積層されて形成された感光層を有する積層型の像担持体において、前記電荷輸送層に、多数の導電性微粒子が周方向かつ膜厚方向に独立分散されており、前記電荷輸送層の表層側での前記導電性微粒子の含有率が高く、かつ前記電荷輸送層の基材側での前記導電性微粒子の含有率が低く設定されていることを特徴としている。 In order to solve the above-mentioned problems, the invention of claim 1 is used in an image forming apparatus, and has a photosensitive layer formed by laminating a charge generation layer and a charge transport layer on a conductive substrate. In the multilayer image carrier, a large number of conductive fine particles are independently dispersed in the circumferential direction and the film thickness direction in the charge transport layer, and the content of the conductive fine particles on the surface layer side of the charge transport layer is It is characterized in that it is high and the content of the conductive fine particles on the substrate side of the charge transport layer is set low.

また、請求項２の発明は、前記電荷輸送層が、前記導電性微粒子が含有されている前記表層側の上層と、前記導電性微粒子が含有されていない前記基材側の下層とからなることを特徴としている。
更に、請求項３の発明は、前記電荷輸送層の導電性微粒子の含有率が、前記表層側から前記基材側に向かって連続してまたは複数段階的に低くなるように設定されていることを特徴としている。 In the invention of claim 2, the charge transport layer is composed of an upper layer on the surface layer side containing the conductive fine particles and a lower layer on the base material side not containing the conductive fine particles. It is characterized by.
Furthermore, the invention of claim 3 is set so that the content of the conductive fine particles in the charge transport layer is continuously or gradually decreased from the surface layer side toward the base material side. It is characterized by.

更に、請求項４の発明は、画像形成装置に用いられ、導電性の基材の上に電荷発生機能と電荷輸送機能とを備える感光層が形成されている単層型の像担持体において、前記感光層に、多数の導電性微粒子が周方向かつ膜厚方向に独立分散されており、前記感光層の表層側での前記導電性微粒子の含有率が高く、かつ前記感光層の基材側での前記導電性微粒子の含有率が低く設定されていることを特徴としている。 Furthermore, the invention of claim 4 is used in an image forming apparatus, and is a single layer type image carrier in which a photosensitive layer having a charge generation function and a charge transport function is formed on a conductive substrate. A large number of conductive fine particles are independently dispersed in the circumferential direction and the film thickness direction in the photosensitive layer, the content of the conductive fine particles on the surface layer side of the photosensitive layer is high, and the substrate side of the photosensitive layer The content of the conductive fine particles in is set to be low.

更に、請求項５の発明は、前記感光層が、前記導電性微粒子が含有されている前記表層側の上層と、前記導電性微粒子が含有されていない前記基材側の下層とからなることを特徴としている。
更に、請求項６の発明は、前記感光層の導電性微粒子の含有率が、前記表層側から前記基材側に向かって連続してまたは複数段階的に低くなるように設定されていることを特徴としている。 Further, the invention of claim 5 is that the photosensitive layer is composed of an upper layer on the surface layer side containing the conductive fine particles and a lower layer on the substrate side not containing the conductive fine particles. It is a feature.
Furthermore, the invention of claim 6 is such that the content of the conductive fine particles in the photosensitive layer is set so as to decrease continuously or in a plurality of steps from the surface layer side toward the base material side. It is a feature.

このように構成された請求項１ないし３の発明に係る像担持体によれば、積層型の感光層の電荷輸送層に多数の導電性微粒子を周方向かつ膜厚方向に混在するようにして独立分散させており、また、請求項４ないし６の発明に係る像担持体によれば、単層型の感光層に多数の導電性微粒子を周方向かつ膜厚方向に混在するようにして独立分散させているので、それぞれ、印字枚数が増加することで像担持体の表層が摩耗しても、像担持体の表面に導電性微粒子を露出させることができる。これにより、像担持体の帯電を長期にわたってより安定して行うことができる。したがって、光書込による潜像形成および帯電書込による潜像形成が長期にわたってできるようになり、両書込による画像形成を長期的にかつより確実に行うことが可能となる。 According to the image carrier of the first to third aspects of the invention thus configured, a large number of conductive fine particles are mixed in the circumferential direction and the film thickness direction in the charge transport layer of the laminated photosensitive layer. Independently dispersed, and according to the image carrier of the inventions of claims 4 to 6, the single-layer type photosensitive layer has a large number of conductive fine particles mixed in the circumferential direction and the film thickness direction. Since they are dispersed, the conductive fine particles can be exposed on the surface of the image carrier even if the surface layer of the image carrier is worn by increasing the number of printed sheets. As a result, the image carrier can be more stably charged over a long period of time. Therefore, latent image formation by optical writing and latent image formation by charging writing can be performed over a long period of time, and image formation by both writings can be performed for a long time and more reliably.

また、像担持体の長期使用等によって像担持体の表面にトナーの樹脂成分等によりフィルミングが生じても、像担持体の表層を積極的に研磨してこのフィルミングを除去することで、新しい導電性微粒子を露出させることができる。これにより、画像形成をより一層長期にわたって確実に行うことができるようになる。 Further, even if filming occurs due to the resin component of the toner on the surface of the image carrier due to long-term use of the image carrier, etc., by actively polishing the surface layer of the image carrier to remove this filming, New conductive fine particles can be exposed. As a result, image formation can be reliably performed for a longer period of time.

更に、導電性微粒子の含有率を、積層型の感光層では電荷輸送層の表層側で高くかつ電荷輸送層の基材側で低く設定し、また単層型の感光層ではこの感光層の表層側で高くかつ感光層の基材側で低く設定しているので、それぞれ、多数の導電性微粒子を電荷輸送層または感光層の膜厚方向に混在させても、帯電、現像、転写等において高電圧が印加された際に起こる電荷のリーク（絶縁破壊）を効果的に防止することができる。 Further, the content of the conductive fine particles is set to be higher on the surface layer side of the charge transport layer and lower on the substrate side of the charge transport layer in the laminated type photosensitive layer, and on the surface layer of this photosensitive layer in the single layer type photosensitive layer. Since it is set high on the side and low on the substrate side of the photosensitive layer, even if a large number of conductive fine particles are mixed in the film thickness direction of the charge transport layer or photosensitive layer, it is high in charging, development, transfer, etc. It is possible to effectively prevent charge leakage (dielectric breakdown) that occurs when a voltage is applied.

更に、積層型の感光層では電荷輸送層の膜厚方向に混在する導電性微粒子が電荷輸送機能をも発揮し、また単層型の感光層ではこの感光層の膜厚方向に混在する導電性微粒子が電荷輸送機能をも発揮することから、電荷輸送における速度（例えば、光反応速度（光書込による潜像形成時、電荷発生材が受光により発生した電荷の輸送速度）等）が向上する。したがって、画像形成装置の高速化や小型化に効果的に対応することが可能となる。 Furthermore, in the multilayer type photosensitive layer, conductive fine particles mixed in the thickness direction of the charge transport layer also exert a charge transport function, and in the single layer type photosensitive layer, the conductivity mixed in the thickness direction of this photosensitive layer. Since the fine particles also exhibit a charge transport function, the speed in charge transport (for example, photoreaction speed (transport speed of charge generated by light reception by the charge generating material when forming a latent image by optical writing), etc.) is improved. . Therefore, it is possible to effectively cope with speeding up and downsizing of the image forming apparatus.

以下、図面を用いて本発明を実施するための最良の形態について説明する。
図１（ａ）は、本発明の画像形成装置における像担持体の実施の形態の第１例を模式的にかつ部分的に示す横断面図、同図（ｂ）はこの第１例の変形例を模式的にかつ部分的に示す横断面図である。 The best mode for carrying out the present invention will be described below with reference to the drawings.
1A is a cross-sectional view schematically and partially showing a first example of an embodiment of an image carrier in an image forming apparatus of the present invention, and FIG. 1B is a modification of the first example. It is a transverse cross section showing an example typically and partially.

図１（ａ）に示すように、この第１例の像担持体１は、基材２と、この基材２上に形成された下引き層（Under Coated Layer：以下、ＵＣＬともいう）３と、このＵＣＬ３上に形成された感光層４とから構成されている。感光層４は、ＵＣＬ３上に形成された電荷発生層（Charge Generation Layer：以下、ＣＧＬともいう）５と、このＣＧＬ５上に形成された電荷輸送層（Charge Transport Layer：以下、ＣＴＬともいう）６とが積層されて形成されている。そして、ＣＴＬ６中には、多数の導電性微粒子７が周方向かつ膜厚方向（径方向）に混在するようにして独立分散されて含有されている。このようにＣＧＬ５およびＣＴＬ６が設けられることで、像担持体１は、電荷発生機能と電荷輸送機能とが分離された機能分離型でかつ積層型の感光体として構成されている。 As shown in FIG. 1A, the image carrier 1 of the first example includes a substrate 2 and an undercoating layer (hereinafter also referred to as UCL) 3 formed on the substrate 2. And a photosensitive layer 4 formed on the UCL 3. The photosensitive layer 4 includes a charge generation layer (hereinafter also referred to as CGL) 5 formed on the UCL 3 and a charge transport layer (hereinafter also referred to as CTL) 6 formed on the CGL 5. Are laminated. And in CTL6, many electroconductive fine particles 7 are independently disperse | distributed and contained so that it may coexist in the circumferential direction and the film thickness direction (radial direction). By providing the CGL 5 and the CTL 6 in this manner, the image carrier 1 is configured as a function-separated type and a laminated type photosensitive member in which the charge generation function and the charge transport function are separated.

基材２は、アルミニウム等の導電性材料から円筒状に形成される。その場合、外径は約３０ｍｍ程度に、また厚みは１〜２ｍｍに形成される。
ＵＣＬ３は、感光層４の表面あるいは基材２からの電荷の注入を阻止する目的で設けられる電気的な絶縁薄膜の層であり、例えば、アミラン樹脂等の樹脂層またはアルマイト層で形成されている。このＵＣＬ３の膜厚は０.５〜５μｍであり、好ましくは０.５〜１.５μｍである。 The base material 2 is formed in a cylindrical shape from a conductive material such as aluminum. In this case, the outer diameter is about 30 mm and the thickness is 1 to 2 mm.
The UCL 3 is a layer of an electrically insulating thin film provided for the purpose of preventing the injection of electric charges from the surface of the photosensitive layer 4 or the substrate 2, and is formed of, for example, a resin layer such as an amylan resin or an alumite layer. . The film thickness of this UCL3 is 0.5-5 micrometers, Preferably it is 0.5-1.5 micrometers.

ＣＧＬ５は、機能分離・積層型感光体で受光時に電荷を発生する機能を分担する層であり、バインダー樹脂中に電荷発生材料（以下、ＣＧ材ともいう）を分散して形成するタイプと、前述の基材２の上にアモルファスＳｉ層を真空蒸着して形成するタイプとがある。このＣＧＬ５の膜厚は０.５〜２μｍであり、好ましくは０.５〜１.５μｍである。 CGL5 is a layer that shares the function of generating charge when receiving light with a function-separated / stacked type photoreceptor, and is formed by dispersing a charge generating material (hereinafter also referred to as CG material) in a binder resin, as described above. There is a type in which an amorphous Si layer is formed on a base material 2 by vacuum deposition. The film thickness of CGL5 is 0.5 to 2 μm, preferably 0.5 to 1.5 μm.

バインダー樹脂中に電荷発生材料を分散するタイプでは、バインダー樹脂として、例えば、ポリビニルブチラール樹脂等の樹脂を用いることができ、また、ＣＧ材として、ビスアゾ系あるいはフタロシアニン系等の顔料を用いることができる。このＣＧＬ５は、ＵＣＬ３上に電荷発生材料を前述の膜厚の範囲内の所定膜厚に塗布することで形成される。そして、ビスアゾ系あるいはフタロシアニン系の顔料を用いることにより、像担持体１は有機感光体（ＯＰＣ）として構成される。
また、基材２の上にアモルファスＳｉ層を真空蒸着するタイプでは、アモルファスＳｉを真空蒸着する際に、導電性微粒子７も同じく真空蒸着して、ＣＧＬ５を形成する。この像担持体１は無機感光体として構成される。 In the type in which the charge generating material is dispersed in the binder resin, for example, a resin such as polyvinyl butyral resin can be used as the binder resin, and a bisazo type or phthalocyanine type pigment can be used as the CG material. . The CGL 5 is formed by applying a charge generation material on the UCL 3 to a predetermined film thickness within the aforementioned film thickness range. By using a bisazo or phthalocyanine pigment, the image carrier 1 is configured as an organic photoreceptor (OPC).
In the type in which an amorphous Si layer is vacuum-deposited on the substrate 2, when the amorphous Si is vacuum-deposited, the conductive fine particles 7 are also vacuum-deposited to form the CGL 5. The image carrier 1 is configured as an inorganic photoreceptor.

ＣＴＬ６は、機能分離・積層型感光体でＣＧＬ５で発生した電荷を輸送する機能を分担する層であり、従来の通常の感光体用バインダー樹脂と同じように誘電体としての性質を示すバインダー樹脂中に、電荷輸送性を有する化合物（以下、ＣＴ材ともいう）を混合して形成される。バインダー樹脂としては、例えば、ポリカーボネート、ポリエチレン、ポリ塩化ビニル、ポリオリフィン、ポリエチレンテレフタレート等の絶縁性を有して誘電体特性を示す樹脂を用いることができる。また、ＣＴ材としては、例えば、ヒドラゾン系等の電荷輸送材料を用いることができる。このＣＴＬ６は、ＣＧＬ５の上に所定膜厚（１０〜３０μｍ）に塗布することで形成される。 CTL6 is a layer that shares the function of transporting charges generated by CGL5 in a functionally separated / stacked type photoconductor, and in the binder resin that exhibits properties as a dielectric, similar to conventional binder resins for photoconductors. And a compound having a charge transporting property (hereinafter also referred to as a CT material). As the binder resin, for example, a resin having dielectric properties such as polycarbonate, polyethylene, polyvinyl chloride, polyolefin, polyethylene terephthalate, or the like can be used. Further, as the CT material, for example, a hydrazone-based charge transport material can be used. The CTL 6 is formed by applying a predetermined film thickness (10 to 30 μm) on the CGL 5.

更に、ＣＴＬ６中に独立分散されている導電性微粒子７としては、Ｗ、Ｍｏ、Ｔａ、Ａｕ、Ａｇ、Ｆｅ等の金属微粒子、あるいは、酸化錫（ＳｎＯ₂）に、アンチモンまたはインジウム等をドービングして導電化処理した微粒子、あるいは、酸化チタン（ＴｉＯ₂）等の他の金属酸化物や導電カーボン等の微粒子を用いることができる。その場合、本発明の像担持体１は、光書込による潜像形成と光を使わない帯電書込による潜像形成との両潜像形成が行われるものであることから、導電性微粒子として、光透過性を有するＳｎＯ₂を前述のように導電化処理した微粒子か、あるいは光書込による場合の光透過性を阻害しない程度の、サブμｍ（１μｍ）以下のより細かい粒径の微粒子を用いることが好ましい。 Further, as the conductive fine particles 7 dispersed independently in the CTL 6, metal fine particles such as W, Mo, Ta, Au, Ag and Fe, or tin oxide (SnO ₂ ) is doped with antimony or indium. Thus, fine particles such as conductive fine particles, or other metal oxides such as titanium oxide (TiO ₂ ) or conductive carbon can be used. In this case, the image carrier 1 according to the present invention performs both latent image formation by latent image formation by optical writing and latent image formation by charging writing without using light. Fine particles obtained by conducting SnO ₂ having optical transparency as described above, or fine particles having a finer particle size of sub-μm (1 μm) or less that do not impair optical transparency in the case of optical writing. It is preferable to use it.

そして、この第１例の像担持体１では、導電性微粒子７の含有率がＣＴＬ６の上層（つまり、表層側の層）Ａで比較的高く、またＣＴＬ６の下層（つまり、基材２側の層）Ｂで比較的低くなるように設定されている。導電性微粒子７の含有率は、ＣＴＬ６内で、ある半径の面における単位面積あたりの導電性微粒子７が被覆する面積で定義される。 In the image carrier 1 of the first example, the content of the conductive fine particles 7 is relatively high in the upper layer (that is, the surface layer side) A of the CTL 6 and the lower layer of the CTL 6 (that is, on the substrate 2 side). Layer) B is set to be relatively low. The content rate of the conductive fine particles 7 is defined by the area covered by the conductive fine particles 7 per unit area on a surface of a certain radius in the CTL 6.

ある半径の面における導電性微粒子７の含有率の評価は、一例として次のようにして行うことができる。すなわち、ＣＴＬ６の表層を削ってある半径の面を表に露出させる。そして、この露出面を光学顕微鏡で観察し、露出面の単位面積あたりの、導電性微粒子７がこの露出面を被覆する面積を測定することで、その面における導電性微粒子７の含有率の評価を行う。なお、露出面の設定面積内において、導電性微粒子７がこの設定面積内の露出面を被覆する面積を測定し、導電性微粒子７の被覆面積を露出面の設定面積で除算することで、導電性微粒子７の含有率の評価を行うこともできる。 The evaluation of the content of the conductive fine particles 7 on the surface having a certain radius can be performed as follows as an example. That is, the surface of the CTL 6 whose surface layer is cut is exposed to the surface. Then, the exposed surface is observed with an optical microscope, and the area of the conductive fine particles 7 covering the exposed surface per unit area of the exposed surface is measured to evaluate the content of the conductive fine particles 7 on the surface. I do. In addition, within the set area of the exposed surface, the area where the conductive fine particles 7 cover the exposed surface within the set area is measured, and the conductive fine particle 7 is divided by the set area of the exposed surface by dividing the conductive area. The content of the conductive fine particles 7 can also be evaluated.

導電性微粒子７が含有されたＣＴＬ６をＣＧＬ５の上に塗布する場合は、ＣＴ材およびバインダー樹脂に導電性微粒子７を含有し、これらを溶剤に溶かした状態で塗布を行う。その場合、溶剤として、ＴＨＦあるいはアセトンを用いることができるが、溶剤はこれに限定されるものではなく、バインダー樹脂を溶かす溶剤であればよい。 When the CTL 6 containing the conductive fine particles 7 is applied on the CGL 5, the application is performed in a state where the conductive fine particles 7 are contained in the CT material and the binder resin and these are dissolved in a solvent. In that case, THF or acetone can be used as the solvent, but the solvent is not limited to this, and any solvent that dissolves the binder resin may be used.

次に、このように構成されたこの第１例の像担持体１の製造方法の一例について説明する。
ＯＰＣとして構成される像担持体１の製造方法としては、従来公知の通常の感光体ドラムの製造方法と基本的に同じであり、像担持体１はディップコーティング法（浸水法）で作製することができる。これを具体的に説明すると、まず、例えば、アルミニウム材からなる外径約３０ｍｍで厚み１.５μｍの円筒状の基材２の上に、例えば絶縁性のアミラン樹脂に、ある程度のイオン導電性を示すメトキシメチル化ナイロンを混合したＵＣＬ液を塗工することで、電気的な絶縁薄膜のＵＣＬ３を約１μｍ程度の膜厚に形成する。 Next, an example of a manufacturing method of the image carrier 1 of the first example configured as described above will be described.
The manufacturing method of the image carrier 1 configured as OPC is basically the same as that of a conventionally known ordinary photosensitive drum, and the image carrier 1 is manufactured by a dip coating method (a water immersion method). Can do. More specifically, first, for example, a certain degree of ionic conductivity is applied to an insulating amylan resin, for example, on a cylindrical base material 2 made of an aluminum material and having an outer diameter of about 30 mm and a thickness of 1.5 μm. By applying a UCL liquid mixed with the methoxymethylated nylon shown, the electrically insulating thin film UCL3 is formed to a thickness of about 1 μm.

次に、形成されたＵＣＬ３の上に、バインダー樹脂であるポリビニルブチラール樹脂と電荷発生材料であるビスアゾ系の顔料とを１：２の重量比で分散したものを塗工することで、ＣＧＬ５を約１μｍの膜厚に形成する。次いで、形成されたＣＧＬ５の上に、バインダー樹脂であるポリカーボネート樹脂とＣＴ材であるヒドラゾンとを１：１の重量比で分散したＣＴＬ用樹脂と、導電性微粒子７であるＭｏ微粒子（（株）高純度科学研究所製）とをＴＨＦの溶剤に溶かして、導電性微粒子７を独立分散させたＣＴＬ用塗液を塗工する。 Next, on the formed UCL3, a dispersion of polyvinyl butyral resin, which is a binder resin, and bisazo pigment, which is a charge generation material, in a weight ratio of 1: 2 is applied to reduce CGL5 to about The film is formed to a thickness of 1 μm. Next, on the formed CGL5, a CTL resin in which a polycarbonate resin as a binder resin and a hydrazone as a CT material are dispersed at a weight ratio of 1: 1, and Mo fine particles (Co., Ltd.) as conductive fine particles 7 High Purity Science Laboratory) is dissolved in a THF solvent, and a CTL coating liquid in which the conductive fine particles 7 are independently dispersed is applied.

その場合、特許文献１に開示されているような従来の通常の感光体ドラムの塗工方法と同じ塗工方法でＣＴＬ用塗液を単に塗工しただけでは、ＣＴＬ６の表層側での導電性微粒子７の含有率が基材２側での導電性微粒子７の含有率より高くなるようにすることはできない。そこで、この第１例の像担持体１では塗工を２回に分けるとともに、１回目および２回目の塗工の際に、ＣＴＬ用塗液として、それぞれ以下のような第１および第２塗工液を用いることで、感光層４における導電性微粒子７の濃度を変えている。 In that case, the conductivity on the surface layer side of CTL6 can be obtained simply by coating the CTL coating liquid by the same coating method as that of a conventional ordinary photosensitive drum as disclosed in Patent Document 1. The content of the fine particles 7 cannot be made higher than the content of the conductive fine particles 7 on the substrate 2 side. Therefore, in the image carrier 1 of the first example, the coating is divided into two times, and the following first and second coatings are respectively used as the CTL coating liquid in the first and second coatings. By using the working solution, the concentration of the conductive fine particles 7 in the photosensitive layer 4 is changed.

すなわち、この例では、１回目の塗工に用いる第１塗工液は次のようにして作製される。平均個数粒径３μｍのＭｏ微粒子（（株）高純度科学研究所製）を重量比Ａ％（例えば、１５％）、前述のＣＴＬ用樹脂を重量比（１００ーＡ）％（例えば、８５％）とし、固形分（導電性微粒子７およびＣＴＬ用樹脂）の濃度が重量比２０％になるように溶剤としてＴＨＦを用いて溶液を作製する。そして、このように平均個数粒径３μｍのＭｏ微粒子、ＣＴＬ用樹脂、およびＴＨＦを混合した溶液を容積５００ｍｌの容器にガラスビーズとともに入れて、ペイントシェーカーによって分散させることで第１塗工液を完成する。 That is, in this example, the first coating liquid used for the first coating is produced as follows. Mo fine particles having an average number particle size of 3 μm (manufactured by Kokusai Kagaku Kenkyusho Co., Ltd.) are in a weight ratio A% (for example, 15%), and the above-mentioned CTL resin is in a weight ratio (100-A)% (for example, 85% ) And a solution is prepared using THF as a solvent so that the concentration of solids (conductive fine particles 7 and CTL resin) is 20% by weight. Then, the first coating liquid is completed by putting a solution containing Mo fine particles having an average particle diameter of 3 μm, a resin for CTL, and THF together with glass beads in a 500 ml container and dispersing with a paint shaker. To do.

また、２回目の塗工に用いる第２塗工液は次のようにして作製される。平均個数粒径３μｍのＭｏ微粒子（（株）高純度科学研究所製）を前述の重量比Ａ％より大きい重量比Ｂ％（Ｂ＞Ａ；例えば、２５％）、前述のＣＴＬ用樹脂を重量比（１００ーＢ）％（例えば、７５％）とし、固形分濃度が重量比２０％になるように溶剤としてＴＨＦを用いて溶液を作製する。そして、このように平均個数粒径３μｍのＭｏ微粒子、ＣＴＬ用樹脂、およびＴＨＦを混合した溶液を第１塗工液の場合と同様に容積５００ｍｌの容器にガラスビーズとともに入れて、ペイントシェーカーによって分散させることで第２塗工液を完成する。 Moreover, the 2nd coating liquid used for the 2nd coating is produced as follows. Mo fine particles having an average number particle size of 3 μm (manufactured by High Purity Science Laboratory Co., Ltd.) having a weight ratio B% (B> A; for example, 25%) larger than the aforementioned weight ratio A%, and the aforementioned CTL resin weight. A solution is prepared using THF as a solvent so that the ratio (100-B)% (for example, 75%) and the solid content concentration is 20% by weight. Then, a solution in which Mo fine particles having an average number particle diameter of 3 μm, a CTL resin, and THF are mixed together is placed in a 500 ml container together with glass beads in the same manner as the first coating liquid, and dispersed by a paint shaker. To complete the second coating liquid.

そして、１回目の塗工で、ＣＧＬ５の上に第１塗工液を塗工して乾燥させることで、第１塗工膜をこのＣＧＬ５上に形成する。次いで、２回目の塗工で第１塗工膜の上に第２塗工液を塗工して乾燥させることで、第２塗工膜をこの第１塗工膜上に形成する。このとき、第１塗工液および第２塗工液の各固形分濃度（混合比）がそれぞれ異なることから各塗工液の粘度が若干異なるが、１回目の塗工および２回目の塗工のいずれの塗工においても、塗工速度はほぼ同じに設定することができる。 Then, the first coating film is formed on the CGL 5 by applying the first coating liquid on the CGL 5 and drying it in the first coating. Next, a second coating film is formed on the first coating film by applying the second coating liquid onto the first coating film and drying it in the second coating. At this time, since the solid content concentrations (mixing ratios) of the first coating liquid and the second coating liquid are different from each other, the viscosity of each coating liquid is slightly different, but the first coating and the second coating are performed. In any of these coating methods, the coating speed can be set substantially the same.

このように、塗工液における導電性微粒子７の濃度を第１回目の塗工で低くかつ第２回目の塗工で高く変えて塗工することで、ＣＴＬ６の表層側での導電性微粒子７の含有率が基材２側での導電性微粒子７の含有率より高い像担持体１を製造することができる。 Thus, the conductive fine particles 7 on the surface layer side of the CTL 6 are applied by changing the concentration of the conductive fine particles 7 in the coating liquid to be low in the first coating and high in the second coating. The image carrier 1 having a higher content than the content of the conductive fine particles 7 on the substrate 2 side can be produced.

この第１例の像担持体１は、感光層４とこの感光層４の電荷輸送層６内に導電性微粒子７が独立分散されていることから、電荷注入による帯電が可能となる。したがって、像担持体１は、帯電書込による潜像形成および光書込による潜像形成のいずれの潜像形成も可能となる。すなわち、第１例の像担持体１は、図２に示すように帯電書込により潜像を形成する画像形成装置９に適用することができる。この画像形成装置９は、像担持体１に静電潜像を書き込む書込ヘッド１０と、書込ヘッド１０を支持する可撓性の基材１１と、現像剤担持体である現像ローラ１２ａおよび現像ローラ１２ａ上の現像剤（トナー）の層厚を規制する現像剤層厚規制部材１２ｂを有する現像装置１２と、転写ローラ１３ａを有する転写装置１３とを少なくとも備えている。 The image carrier 1 of the first example can be charged by charge injection since the conductive fine particles 7 are independently dispersed in the photosensitive layer 4 and the charge transport layer 6 of the photosensitive layer 4. Therefore, the image carrier 1 can form either a latent image by charging writing or a latent image by optical writing. That is, the image carrier 1 of the first example can be applied to an image forming apparatus 9 that forms a latent image by charging writing as shown in FIG. The image forming apparatus 9 includes a writing head 10 that writes an electrostatic latent image on the image carrier 1, a flexible base 11 that supports the writing head 10, a developing roller 12a that is a developer carrier, and The image forming apparatus includes at least a developing device 12 having a developer layer thickness regulating member 12b that regulates a layer thickness of the developer (toner) on the developing roller 12a and a transfer device 13 having a transfer roller 13a.

そして、書込ヘッド１０をＣＴＬ６に当接させ、この書込ヘッド１０の書込電圧によりＣＴＬ６表面の導電性微粒子７に電荷を注入することで、潜像が像担持体１に書き込まれる。像担持体１に書き込まれた潜像は現像装置１２の現像剤（トナー）によって現像され、その現像剤（トナー）像が転写装置１３によって図示しない紙等の転写材に転写される。転写材に転写された現像剤（トナー）像は図示しない定着装置によって定着され、転写材上に画像が形成される。 Then, the latent image is written on the image carrier 1 by bringing the write head 10 into contact with the CTL 6 and injecting electric charges into the conductive fine particles 7 on the surface of the CTL 6 by the write voltage of the write head 10. The latent image written on the image carrier 1 is developed by the developer (toner) of the developing device 12, and the developer (toner) image is transferred to a transfer material such as paper (not shown) by the transfer device 13. The developer (toner) image transferred to the transfer material is fixed by a fixing device (not shown), and an image is formed on the transfer material.

また、第１例の像担持体１は、図３に示すように光書込により潜像を形成する画像形成装置９に適用することもできる。この画像形成装置９は、像担持体１を一様帯電する帯電装置１４と、像担持体１に露光により静電潜像を書き込む露光装置１５と、図２に示す現像装置１２と同様の現像装置１２と、図２に示す転写装置１３と同様の転写装置１３とを少なくとも備えている。 The image carrier 1 of the first example can also be applied to an image forming apparatus 9 that forms a latent image by optical writing as shown in FIG. The image forming apparatus 9 includes a charging device 14 for uniformly charging the image carrier 1, an exposure device 15 for writing an electrostatic latent image on the image carrier 1 by exposure, and development similar to the developing device 12 shown in FIG. The apparatus 12 includes at least a transfer apparatus 13 similar to the transfer apparatus 13 illustrated in FIG.

そして、帯電装置１４で帯電した像担持体１を露光装置１５によって露光すると、ＣＧＬ５がこの光を受光して電荷を発生し、この電荷がＣＴＬ６によって表面に輸送されることで、潜像が像担持体１に書き込まれる。以下、図２に示す画像形成装置９の場合と同様にして、現像、転写および定着が行われて転写材上に画像が形成される。 When the image carrier 1 charged by the charging device 14 is exposed by the exposure device 15, the CGL 5 receives this light to generate charges, and the charges are transported to the surface by the CTL 6, so that the latent image is imaged. It is written on the carrier 1. Thereafter, development, transfer, and fixing are performed in the same manner as in the case of the image forming apparatus 9 shown in FIG. 2, and an image is formed on the transfer material.

なお、図１（ａ）に示す第１例の像担持体１では、基材２の上にＵＣＬ３を設けるものとしているが、このＵＣＬ３は省略することもできる。したがって、本発明で基材２の上に感光層４を形成するとは、感光層４を直接基材２の上に形成する場合および感光層４を基材２の上にＵＣＬ３を介して形成する場合のいずれの場合もいう。 In the image carrier 1 of the first example shown in FIG. 1A, the UCL 3 is provided on the base material 2, but this UCL 3 can be omitted. Therefore, the formation of the photosensitive layer 4 on the substrate 2 in the present invention means that the photosensitive layer 4 is formed directly on the substrate 2 and the photosensitive layer 4 is formed on the substrate 2 via the UCL 3. In any case.

また、第１例の変形例として、図１（ｂ）に示すように特許文献１に開示の像担持体と同様の電荷注入防止層（以下、ＣＰＬともいう）８を、基材２とＵＣＬ３との間に設けることもできる。このＣＰＬ８により、基材２とその上の各塗布層（ＵＣＬ３、ＣＧＬ５、ＣＴＬ６）との間での電荷注入防止をより確実にすることができる。ＣＰＬ８の膜厚は０.５〜５μｍであり、好ましくは０.５〜１.５μｍである。また、ＣＰＬ８の材料としては、ＵＣＬ３の材料と同様の材料を用いることができるが、ＣＰＬ８の材料は使用したＵＣＬ３の材料と異なる材料を選択することが好ましい。 Further, as a modification of the first example, as shown in FIG. 1B, a charge injection preventing layer (hereinafter also referred to as CPL) 8 similar to the image carrier disclosed in Patent Document 1 is formed by using a base material 2 and UCL3. It can also be provided between. With this CPL8, it is possible to more reliably prevent charge injection between the substrate 2 and each coating layer (UCL3, CGL5, CTL6) thereon. The film thickness of CPL8 is 0.5 to 5 μm, preferably 0.5 to 1.5 μm. Further, as the material of CPL8, the same material as the material of UCL3 can be used, but it is preferable to select a material different from the material of UCL3 used as the material of CPL8.

また、図１（ｂ）に示す変形例の像担持体１を、図２および図３にそれぞれ示す画像形成装置９,１０の像担持体１に適用した場合も、同様にして書込ヘッド１０を用いた帯電書込による画像形成および露光装置１５を用いた光書込による画像形成をともに行うことができる。 In addition, when the image carrier 1 of the modification shown in FIG. 1B is applied to the image carrier 1 of the image forming apparatuses 9 and 10 shown in FIGS. It is possible to perform both image formation by charging writing using and image formation by optical writing using the exposure device 15.

このように第１例およびその変形例の像担持体１によれば、感光層４のＣＴＬ６中に多数の導電性微粒子７を周方向かつ膜厚方向に混在するようにして独立分散させて配置しているので、印字枚数が増加することで像担持体１の表層が摩耗しても、像担持体１の表面に導電性微粒子７を露出させることができる。これにより、像担持体１の帯電を長期にわたってより安定して行うことができる。したがって、光書込による潜像形成および帯電書込による潜像形成が長期にわたってできるようになり、両書込による画像形成を長期的にかつより確実に行うことが可能となる。その場合、像担持体１の長期使用等によって像担持体１の表面にトナーの樹脂成分等によりフィルミングが生じても、像担持体１の表層を積極的に研磨してこのフィルミングを除去することで、新しい導電性微粒子７を露出させることができるので、画像形成をより一層長期にわたって確実に行うことができるようになる。 As described above, according to the image carrier 1 of the first example and the modified example thereof, a large number of conductive fine particles 7 are arranged in the CTL 6 of the photosensitive layer 4 so as to be dispersed independently so as to be mixed in the circumferential direction and the film thickness direction. Therefore, even if the surface layer of the image carrier 1 is worn by increasing the number of printed sheets, the conductive fine particles 7 can be exposed on the surface of the image carrier 1. Thereby, the image carrier 1 can be more stably charged over a long period of time. Therefore, latent image formation by optical writing and latent image formation by charging writing can be performed over a long period of time, and image formation by both writings can be performed for a long time and more reliably. In this case, even if filming occurs on the surface of the image carrier 1 due to the resin component of the toner due to long-term use of the image carrier 1, the surface layer of the image carrier 1 is actively polished to remove this filming. By doing so, since the new conductive fine particles 7 can be exposed, it is possible to reliably perform image formation for a longer period of time.

また、多数の導電性微粒子７をＣＴＬ６の膜厚方向に混在させると、帯電、現像、転写等において高電圧が印加された際、像担持体１の深さ方向（膜厚方向）でリーク（絶縁破壊）が起こる。しかし、第１例およびその変形例の像担持体１によれば、導電性微粒子７の含有率をＣＴＬ６の表層側で高くかつＣＴＬ６の基材２側で低く設定しているので、多数の導電性微粒子７をＣＴＬ６の膜厚方向に混在させても、像担持体１の深さ方向で電荷のリーク（絶縁破壊）を効果的に防止することができる。 Further, when a large number of conductive fine particles 7 are mixed in the film thickness direction of the CTL 6, when a high voltage is applied during charging, development, transfer, etc., leakage occurs in the depth direction (film thickness direction) of the image carrier 1 ( Dielectric breakdown) occurs. However, according to the image carrier 1 of the first example and its modified example, the content of the conductive fine particles 7 is set to be high on the surface layer side of the CTL 6 and low on the base material 2 side of the CTL 6. Even if the conductive fine particles 7 are mixed in the film thickness direction of the CTL 6, it is possible to effectively prevent charge leakage (dielectric breakdown) in the depth direction of the image carrier 1.

更に、ＣＴＬ６の膜厚方向に混在する導電性微粒子７が電荷輸送機能をも発揮することから、電荷輸送における速度（例えば、光反応速度（光書込による潜像形成時、ＣＧＬ５で受光により発生した電荷の輸送速度）等）が向上する。したがって、画像形成装置の高速化や小型化に効果的に対応することが可能となる。 Furthermore, since the conductive fine particles 7 mixed in the film thickness direction of the CTL 6 also exhibit the charge transport function, the charge transport speed (for example, photoreaction speed (generated by light reception by the CGL 5 when forming a latent image by optical writing). The transport rate of the generated charges)) is improved. Therefore, it is possible to effectively cope with speeding up and downsizing of the image forming apparatus.

図４は、本発明の像担持体の実施の形態の第２例を模式的にかつ部分的に示す、図１（ａ）と同様の横断面図である。なお、以下の実施の形態の各例の説明において、その例より前に説明されている例と同じ構成要素には同じ符号を付すことで、その詳細な説明は省略する。
前述の図１（ａ）および（ｂ）に示す第１例の像担持体１では、ＣＴＬ６の基材２側に導電性微粒子７が含有されているが、図４に示すように、この第２例の像担持体１では、ＣＴＬ６の下層（つまり、基材２側の層）Ｂには、導電性微粒子７は含有されていない。また、ＣＴＬ６の上層（つまり、表層側の層）Ａには、多数の導電性微粒子７が前述と同様に独立分散されて含有されている。
このようにＣＴＬ６の下層（つまり、基材２側の層）Ｂに導電性微粒子７が含有されない場合にも、導電性微粒子７の含有率がＣＴＬ６の表層側で高く、ＣＴＬ６の基材２側で低い本発明の像担持体１に含むものとする。 FIG. 4 is a cross-sectional view similar to FIG. 1A schematically and partially showing a second example of the embodiment of the image carrier of the present invention. In the description of each example of the following embodiment, the same components as those described before the example are denoted by the same reference numerals, and detailed description thereof is omitted.
In the image carrier 1 of the first example shown in FIGS. 1A and 1B described above, the conductive fine particles 7 are contained on the base 2 side of the CTL 6, but as shown in FIG. In the image carrier 1 of the two examples, the conductive fine particles 7 are not contained in the lower layer (that is, the layer on the substrate 2 side) B of the CTL 6. The upper layer (namely, the surface layer side) A of the CTL 6 contains a large number of conductive fine particles 7 that are independently dispersed as described above.
Thus, even when the conductive fine particles 7 are not contained in the lower layer (that is, the layer on the base material 2 side) B of the CTL 6, the content of the conductive fine particles 7 is high on the surface layer side of the CTL 6, and the base material 2 side of the CTL 6 And low in the image carrier 1 of the present invention.

この第２例の像担持体１の製造方法においては、前述の第１例の像担持体１の製造方法の場合と同じように塗工液を２回に分けて塗工する。そして、第１回目の塗工液の塗工では、導電性微粒子７がまったく含まれないＣＴＬ用塗液を用いる。また、第２回目のＣＴＬ用塗液の塗工では、第１例の像担持体１の製造方法における第２回目の塗工で用いられるＣＴＬ用塗液とまったく同じように導電性微粒子７が含有されたＣＴＬ用塗液を用いる。第２例の像担持体１の製造方法の他の工程は、第１例の像担持体１の製造方法と同じである。
また、第２例の像担持体１の他の構成および他の作用効果は第１例の像担持体１と同じである。 In the method for manufacturing the image carrier 1 of the second example, the coating liquid is applied in two steps in the same manner as in the method for manufacturing the image carrier 1 of the first example. In the first coating of the coating liquid, a CTL coating liquid that does not contain the conductive fine particles 7 is used. In the second coating of the CTL coating liquid, the conductive fine particles 7 are formed in exactly the same way as the CTL coating liquid used in the second coating in the manufacturing method of the image carrier 1 of the first example. The contained CTL coating solution is used. Other steps of the manufacturing method of the image carrier 1 of the second example are the same as the manufacturing method of the image carrier 1 of the first example.
The other configurations and other functions and effects of the image carrier 1 of the second example are the same as those of the image carrier 1 of the first example.

図５は、本発明の像担持体の実施の形態の第３例を模式的にかつ部分的に示す、図１（ａ）と同様の横断面図である。
前述の図１（ａ）および（ｂ）に示す第１例の像担持体１では、ＣＴＬ６の上層Ａでの導電性微粒子７の含有率が高く、ＣＴＬ６の下層Ｂでの導電性微粒子７の含有率が低く設定されているが、この第３例の像担持体１では、導電性微粒子７の含有率が、ＣＴＬ６の表層側から基材２側に向かって漸次（連続的にまたは複数段階的に）低くなる（漸減する）ように、グラデーション構造の導電性微粒子７の含有率に設定されている。 FIG. 5 is a cross-sectional view similar to FIG. 1A schematically and partially showing a third example of the embodiment of the image carrier of the present invention.
In the image carrier 1 of the first example shown in FIGS. 1A and 1B described above, the content of the conductive fine particles 7 in the upper layer A of the CTL 6 is high, and the conductive fine particles 7 in the lower layer B of the CTL 6 Although the content rate is set low, in the image carrier 1 of the third example, the content rate of the conductive fine particles 7 gradually (continuously or in multiple stages) from the surface layer side of the CTL 6 toward the substrate 2 side. The content of the conductive fine particles 7 having a gradation structure is set so as to be lower (gradually reduced).

この第３例の像担持体１の製造方法について説明する。
前述の第１および第２例の像担持体１の製造方法ではＣＴＬ用塗液を２回に分けて塗工しているが、図５に示すようにこの第３例の像担持体１の製造方法では、ＣＴＬ用塗液を３回以上の複数回に分けて塗工する。その場合、第１回目の塗工で用いられるＣＴＬ用塗液には導電性微粒子７が含まれないか、導電性微粒子７が含まれてもその含有率が最も低く設定され、また、第２回目の塗工で用いられるＣＴＬ用塗液の導電性微粒子７の含有率が第１回目のＣＴＬ用塗液より若干高く設定され、更に、第３回目の塗工で用いられるＣＴＬ用塗液の導電性微粒子７の含有率が第２回目のＣＴＬ用塗液より若干高く設定され、以下、塗工回数が多くなるにしたがって、ＣＴＬ用塗液の導電性微粒子７の含有率が漸次高くなるように設定される。 A method for manufacturing the image carrier 1 of the third example will be described.
In the manufacturing method of the image carrier 1 of the first and second examples described above, the CTL coating liquid is applied in two steps. However, as shown in FIG. In the production method, the CTL coating liquid is applied in three or more times. In that case, the conductive liquid 7 is not included in the CTL coating liquid used in the first coating, or even if the conductive fine particles 7 are included, the content is set to be the lowest. The content of the conductive fine particles 7 in the CTL coating liquid used in the second coating is set to be slightly higher than that in the first CTL coating liquid, and the CTL coating liquid used in the third coating is further increased. The content of the conductive fine particles 7 is set to be slightly higher than that of the second CTL coating liquid, and the content of the conductive fine particles 7 of the CTL coating liquid is gradually increased as the number of coatings is increased. Set to

このように３回以上の複数回に分けて、漸次高くなる導電性微粒子７の含有率のＣＴＬ用塗液を順次塗工することで、導電性微粒子７の含有率が前述のグラデーション構造である像担持体１が形成される。第３例の像担持体１の製造方法の他の工程は、第１例の像担持体１の製造方法と同じである。
また、第３例の像担持体１の他の構成および他の作用効果は第１例の像担持体１と同じである。 In this manner, the CTL coating liquid having a gradually increasing content of the conductive fine particles 7 is sequentially applied in three or more times, so that the content of the conductive fine particles 7 is the above-described gradation structure. An image carrier 1 is formed. The other steps of the manufacturing method of the image carrier 1 of the third example are the same as the manufacturing method of the image carrier 1 of the first example.
The other configurations and other functions and effects of the image carrier 1 of the third example are the same as those of the image carrier 1 of the first example.

図６は、本発明の像担持体の実施の形態の第４例を模式的にかつ部分的に示す、図１（ａ）と同様の横断面図である。
前述の第１ないし第３例の像担持体１では、感光層４がＣＧＬ５とＣＴＬ６とに分離積層された機能分離型・積層型の像担持体１として構成されているが、図６に示すように、この第４例の像担持体１は、感光層４が電荷発生機能と電荷輸送機能をが分離されず１層でこれらの両機能を有する単層型の像担持体１として構成されている。 FIG. 6 is a cross-sectional view similar to FIG. 1A schematically and partially showing a fourth example of the embodiment of the image carrier of the present invention.
The image carrier 1 of the first to third examples is configured as a function-separated / stacked image carrier 1 in which the photosensitive layer 4 is separated and laminated on the CGL 5 and the CTL 6 as shown in FIG. As described above, the image carrier 1 of the fourth example is configured as a single-layer image carrier 1 in which the photosensitive layer 4 does not separate the charge generation function and the charge transport function and has both these functions in one layer. ing.

すなわち、第４例の像担持体１における感光層４は、バインダー樹脂１６中に多数の光導電性微粒子１７がほぼ均一に分散されて構成されている。バインダー樹脂１６としては、例えば、ポリカーボネート樹脂、ポリアセチレン樹脂、ポリイミド樹脂、ポリ酢酸ビニル樹脂等の樹脂を用いることができ、また、これらに限定されることはなく、絶縁性を有して誘電体特性を示す樹脂であればどのような樹脂を用いることもできる。光導電性微粒子１７は電荷発生機能および電荷輸送機能の両機能を有し、酸化亜鉛粒子やフタロシアニン顔料などを用いることができる。 That is, the photosensitive layer 4 in the image carrier 1 of the fourth example is configured by a large number of photoconductive fine particles 17 being dispersed almost uniformly in a binder resin 16. As the binder resin 16, for example, a resin such as a polycarbonate resin, a polyacetylene resin, a polyimide resin, or a polyvinyl acetate resin can be used. However, the binder resin 16 is not limited thereto, and has insulating properties and dielectric properties. Any resin can be used as long as the resin exhibits the above. The photoconductive fine particles 17 have both a charge generation function and a charge transport function, and zinc oxide particles, phthalocyanine pigments, and the like can be used.

更に、樹脂１６中には多数の導電性微粒子７が感光層４の周方向かつ膜厚方向（径方向）に独立分散されて含有されている。その場合、第１例の像担持体１と同様に、導電性微粒子７の含有率が感光層４の上層（つまり、表層側の層）Ｃで比較的高く、また感光層４の下層（つまり、基材２側の層）Ｄで比較的低くなるように設定されている。このときの導電性微粒子７の含有率は、感光層４内で、ある半径の面における単位面積あたりの導電性微粒子７が被覆する面積で定義される。 Further, the resin 16 contains a large number of conductive fine particles 7 which are dispersed independently in the circumferential direction and the film thickness direction (radial direction) of the photosensitive layer 4. In that case, like the image carrier 1 of the first example, the content of the conductive fine particles 7 is relatively high in the upper layer (that is, the surface layer side) C of the photosensitive layer 4, and the lower layer (that is, the surface of the photosensitive layer 4) The layer 2 on the substrate 2 side) D is set to be relatively low. The content of the conductive fine particles 7 at this time is defined by the area covered by the conductive fine particles 7 per unit area on a surface of a certain radius in the photosensitive layer 4.

この第４例の像担持体１の製造方法について説明する。
アルミニウムの基材２にＵＣＬ３を形成する工程は前述の第１例と同じである。次に、形成されたＵＣＬ３の上に、バインダー樹脂であるポリカーボネート樹脂と光導電性微粒子１７であるフタロシアニン顔料とを１：１の重量比で分散した感光層用材料と、導電性微粒子７であるＭｏ微粒子（（株）高純度科学研究所製）とをＴＨＦの溶剤に溶かして、導電性微粒子７を独立分散させた塗工液を塗工する。
その場合、第１例の場合と同様にして塗工を２回に分けるとともに、１回目および２回目の塗工の際に、塗工液として、それぞれ以下のような第１および第２塗工液を用いることで、感光層４における導電性微粒子７の濃度を変えている。 A method for manufacturing the image carrier 1 of the fourth example will be described.
The process of forming UCL3 on the aluminum base 2 is the same as in the first example. Next, a photosensitive layer material in which a polycarbonate resin as a binder resin and a phthalocyanine pigment as a photoconductive fine particle 17 are dispersed at a weight ratio of 1: 1 on the formed UCL3, and the conductive fine particle 7 are obtained. Mo fine particles (manufactured by High Purity Science Laboratory Co., Ltd.) are dissolved in a THF solvent, and a coating liquid in which the conductive fine particles 7 are independently dispersed is applied.
In that case, the coating is divided into two in the same manner as in the first example, and the following first and second coatings are used as coating liquids in the first and second coatings, respectively. By using the solution, the concentration of the conductive fine particles 7 in the photosensitive layer 4 is changed.

すなわち、この第４例では、１回目の塗工に用いる第１塗工液は次のようにして作製される。平均個数粒径３μｍのＭｏ微粒子（（株）高純度科学研究所製）を重量比Ｃ％（例えば、１５％）、前述の感光層用材料を重量比（１００ーＣ）％（例えば、８５％）とし、固形分（導電性微粒子７および感光層用材料）の濃度が重量比２０％になるように溶剤としてＴＨＦを用いて溶液を作製する。そして、このように平均個数粒径３μｍのＭｏ微粒子、感光層用材料、およびＴＨＦを混合した溶液を容積５００ｍｌの容器にガラスビーズとともに入れて、ペイントシェーカーによって分散させることで第１塗工液を完成する。 That is, in the fourth example, the first coating liquid used for the first coating is produced as follows. Mo fine particles having an average number particle size of 3 μm (manufactured by Kokusai Kagaku Kenkyusho Co., Ltd.) are in a weight ratio of C% (for example, 15%), and the photosensitive layer material is in a weight ratio of (100-C)% (for example, 85). %), And a solution is prepared using THF as a solvent so that the concentration of solids (conductive fine particles 7 and photosensitive layer material) is 20% by weight. Then, a solution in which Mo fine particles having an average number particle diameter of 3 μm, a photosensitive layer material, and THF are mixed together is put together with glass beads in a 500 ml container, and dispersed by a paint shaker, whereby the first coating liquid is obtained. Complete.

また、２回目の塗工に用いる第２塗工液は次のようにして作製される。平均個数粒径３μｍのＭｏ微粒子（（株）高純度科学研究所製）を前述の重量比Ｃ％より大きい重量比Ｄ％（Ｄ＞Ｃ；例えば、２５％）、前述の感光層用材料を重量比（１００ーＤ）％（例えば、７５％）とし、固形分濃度が重量比２０％になるように溶剤としてＴＨＦを用いて溶液を作製する。そして、このように平均個数粒径３μｍのＭｏ微粒子、感光層用材料、およびＴＨＦを混合した溶液を第１塗工液の場合と同様に容積５００ｍｌの容器にガラスビーズとともに入れて、ペイントシェーカーによって分散させることで第２塗工液を完成する。 Moreover, the 2nd coating liquid used for the 2nd coating is produced as follows. Mo fine particles having an average number particle size of 3 μm (manufactured by High Purity Science Laboratory Co., Ltd.) having a weight ratio D% (D> C; for example, 25%) larger than the above-mentioned weight ratio C%, A solution is prepared using THF as a solvent so that the weight ratio (100-D)% (for example, 75%) and the solid content concentration is 20% by weight. Then, a solution in which Mo fine particles having an average number particle size of 3 μm, a photosensitive layer material, and THF are mixed together is put in a 500 ml container together with glass beads in the same manner as in the case of the first coating solution. The second coating liquid is completed by dispersing.

そして、１回目および２回目の各塗工は、前述の第１例の像担持体１の場合と同じであり、これらの２回の塗工により、感光層４の表層側での導電性微粒子７の含有率が基材２側での導電性微粒子７の含有率より高い第４例の像担持体１を製造することができる。この第４例の像担持体１も、帯電書込による潜像形成および光書込による潜像形成のいずれの潜像形成も可能となる。
第４例の像担持体１の他の構成および他の作用効果は第１例の像担持体１と同じである。 The first coating and the second coating are the same as in the case of the image carrier 1 of the first example described above, and the conductive fine particles on the surface layer side of the photosensitive layer 4 are obtained by these two coatings. Thus, the image carrier 1 of the fourth example in which the content rate of 7 is higher than the content rate of the conductive fine particles 7 on the substrate 2 side can be produced. The image carrier 1 of the fourth example can also form either a latent image by charging writing or a latent image by optical writing.
Other configurations and other functions and effects of the image carrier 1 of the fourth example are the same as those of the image carrier 1 of the first example.

図７は、本発明の像担持体の実施の形態の第５例を模式的にかつ部分的に示す、図１（ａ）と同様の横断面図である。
前述の図６に示す第４例の像担持体１では、感光層４の基材２側に導電性微粒子７が含有されているが、図７に示すようにこの第５例の像担持体１では、感光層４の下層（つまり、基材２側の層）Ｄには、導電性微粒子７は含有されていない。また、感光層４の上層（つまり、表層側の層）Ｃには、多数の導電性微粒子７が前述と同様に独立分散されて含有されている。 FIG. 7 is a cross-sectional view similar to FIG. 1A schematically and partially showing a fifth example of the embodiment of the image carrier of the present invention.
In the image carrier 1 of the fourth example shown in FIG. 6 described above, the conductive fine particles 7 are contained on the side of the substrate 2 of the photosensitive layer 4, but the image carrier of this fifth example as shown in FIG. 1, the conductive fine particles 7 are not contained in the lower layer D (that is, the layer on the substrate 2 side) D of the photosensitive layer 4. The upper layer (that is, the surface layer) C of the photosensitive layer 4 contains a large number of conductive fine particles 7 that are independently dispersed as described above.

この第５例の像担持体１の製造方法においては、前述の第４例の像担持体１の製造方法の場合と同じように感光層４を形成するための塗工液を２回に分けて塗工する。そして、第１回目の塗工では、第４例の第１塗工液で導電性微粒子７がまったく含まれない塗工液を用いる。また、第２回目の塗工では、第４例の第２塗工液とまったく同じように導電性微粒子７が含有された塗工液を用いる。第５例の像担持体１の製造方法の他の工程は、第４例の像担持体１の製造方法と同じである。
また、第５例の像担持体１の他の構成および他の作用効果は第４例の像担持体１と同じである。 In the manufacturing method of the image carrier 1 of the fifth example, the coating liquid for forming the photosensitive layer 4 is divided into two times as in the manufacturing method of the image carrier 1 of the fourth example. Apply. In the first coating, a coating liquid that does not contain the conductive fine particles 7 in the first coating liquid of the fourth example is used. In the second coating, a coating liquid containing conductive fine particles 7 is used just like the second coating liquid in the fourth example. Other steps of the manufacturing method of the image carrier 1 of the fifth example are the same as the manufacturing method of the image carrier 1 of the fourth example.
The other configurations and other functions and effects of the image carrier 1 of the fifth example are the same as those of the image carrier 1 of the fourth example.

図８は、本発明の像担持体の実施の形態の第６例を模式的にかつ部分的に示す、図１（ａ）と同様の横断面図である。
前述の図６に示す第４例の像担持体１では、感光層４の上層Ｃでの導電性微粒子７の含有率が高く、感光層４の下層Ｄでの導電性微粒子７の含有率が低く設定されているが、図８に示すようにこの第６例の像担持体１では、導電性微粒子７の含有率が、感光層４の表層側から基材２側に向かって漸次（連続的にまたは複数段階的に）低くなる（漸減する）ように、グラデーション構造の導電性微粒子７の含有率に設定されている。 FIG. 8 is a cross-sectional view similar to FIG. 1A schematically and partially showing a sixth example of the embodiment of the image carrier of the present invention.
In the image carrier 1 of the fourth example shown in FIG. 6 described above, the content of the conductive fine particles 7 in the upper layer C of the photosensitive layer 4 is high, and the content of the conductive fine particles 7 in the lower layer D of the photosensitive layer 4 is high. As shown in FIG. 8, in the image carrier 1 of the sixth example, the content of the conductive fine particles 7 gradually (continuously) from the surface layer side of the photosensitive layer 4 toward the substrate 2 side as shown in FIG. The content of the conductive fine particles 7 having a gradation structure is set so as to be lowered (gradually reduced) in a stepwise manner or in a plurality of steps.

この第６例の像担持体１の製造方法について説明する。
この第６例の像担持体１の製造方法では、第３例の場合と同様に、感光層４を形成するための塗工液を３回以上の複数回に分けて塗工する。その場合、第１回目の塗工で用いられる第１塗工液には導電性微粒子７が含まれないか、導電性微粒子７が含まれてもその含有率が最も低く設定され、また、第２回目の塗工で用いられる第２塗工液の導電性微粒子７の含有率が第１塗工液より若干高く設定され、更に、第３回目の塗工で用いられる第３塗工液の導電性微粒子７の含有率が第２塗工液より若干高く設定され、以下、塗工回数が多くなるにしたがって、感光層４を形成するための塗工液における導電性微粒子７の含有率が漸次高くなるように設定される。 A method for manufacturing the image carrier 1 of the sixth example will be described.
In the manufacturing method of the image carrier 1 of the sixth example, as in the case of the third example, the coating liquid for forming the photosensitive layer 4 is applied in three or more times. In that case, the first coating liquid used in the first coating does not include the conductive fine particles 7, or even if the conductive fine particles 7 are included, the content rate is set to the lowest, The content of the conductive fine particles 7 in the second coating liquid used in the second coating is set slightly higher than that in the first coating liquid, and the third coating liquid used in the third coating is further increased. The content of the conductive fine particles 7 is set slightly higher than that of the second coating liquid. Hereinafter, as the number of times of coating increases, the content of the conductive fine particles 7 in the coating liquid for forming the photosensitive layer 4 increases. It is set to gradually increase.

このように３回以上の複数回に分けて、漸次高くなる導電性微粒子７の含有率の感光層用の塗工液を順次塗工することで、導電性微粒子７の含有率が前述のグラデーション構造である像担持体１が形成される。第６例の像担持体１の製造方法の他の工程は、第４例の像担持体１の製造方法と同じである。
また、第６例の像担持体１の他の構成および他の作用効果は第４例の像担持体１と同じである。 In this way, the coating solution for the photosensitive layer having a gradually increasing content of the conductive fine particles 7 is sequentially applied in three or more times, so that the content of the conductive fine particles 7 becomes the gradation described above. An image carrier 1 having a structure is formed. The other steps of the manufacturing method of the image carrier 1 of the sixth example are the same as the manufacturing method of the image carrier 1 of the fourth example.
The other configurations and other functions and effects of the image carrier 1 of the sixth example are the same as those of the image carrier 1 of the fourth example.

なお、前述の第１ないし第６例では、ペイントシェーカーによって塗工液の分散を行っているが、超音波振動子を、前述の平均個数粒径３μｍのＭｏ微粒子、ＣＴＬ用樹脂、およびＴＨＦを混合した溶液の中に入れて、超音波による振動エネルギを利用することで塗工液を分散させてもよく、また、塗工液の分散は単なる振動や撹拌等の他の分散方法で行うこともできる。更に、導電性微粒子７としてミクロパールＡＵ（積水化学工業（株）製）を用いることで、塗工液を簡単に作製することもできる。このミクロパールＡＵは、樹脂微粒子の外周にＡＵが金属めっきされている製造されているため、金属微粒子よりも比重が小さく、感光層４を塗布する際に塗布液の分散性がよくなり、しいては塗布工程での生産性が向上するという効果を期待できる。 In the first to sixth examples described above, the coating liquid is dispersed by a paint shaker. However, the ultrasonic vibrator is composed of the aforementioned Mo fine particles having an average number particle size of 3 μm, a CTL resin, and THF. The coating liquid may be dispersed by using ultrasonic vibration energy in a mixed solution, and the coating liquid may be dispersed by other dispersion methods such as simple vibration and stirring. You can also. Furthermore, by using Micropearl AU (manufactured by Sekisui Chemical Co., Ltd.) as the conductive fine particles 7, a coating solution can be easily produced. Since this micropearl AU is manufactured in which AU is metal-plated on the outer periphery of the resin fine particles, the specific gravity is smaller than that of the metal fine particles, and the dispersibility of the coating solution is improved when the photosensitive layer 4 is applied. Therefore, the effect of improving the productivity in the coating process can be expected.

また、第２ないし第６例の像担持体１も、図２に示す帯電書込による潜像形成の画像形成装置９および図３に示す光書込による潜像形成の画像形成装置９に適用することができる。
更に、前述の第４ないし第６例の像担持体においては、光導電性微粒子１７に代えて前述のＣＧ材とＣＴ材とをバインダー樹脂１６中に同時に分散させて感光層４を形成することもできる。 The image carriers 1 of the second to sixth examples are also applied to the latent image forming image forming apparatus 9 by charging writing shown in FIG. 2 and the latent image forming image forming apparatus 9 by optical writing shown in FIG. can do.
Further, in the image carriers of the fourth to sixth examples, the photosensitive layer 4 is formed by simultaneously dispersing the CG material and the CT material in the binder resin 16 instead of the photoconductive fine particles 17. You can also.

本発明の画像形成装置および画像形成方法は、電子写真、静電複写機、プリンタ、ファクシミリ等の像担持体に静電潜像を形成する画像形成装置および画像形成方法に好適に利用することができる。 The image forming apparatus and the image forming method of the present invention can be suitably used for an image forming apparatus and an image forming method for forming an electrostatic latent image on an image carrier such as an electrophotographic, electrostatic copying machine, printer, or facsimile. it can.

（ａ）は、本発明の画像形成装置における像担持体の実施の形態の第１例を模式的にかつ部分的に示す横断面図、同図（ｂ）はこの第１例の変形例を模式的にかつ部分的に示す横断面図である。(A) is a cross-sectional view schematically and partially showing a first example of an embodiment of an image carrier in the image forming apparatus of the present invention, and (b) is a modified example of the first example. It is a transverse cross section showing typically and partially. 本発明の像担持体が適用される帯電書込（電荷注入方式）による潜像形成を行う画像形成装置の一例を模式的に示す図である。1 is a diagram schematically illustrating an example of an image forming apparatus that performs latent image formation by charge writing (charge injection method) to which an image carrier of the present invention is applied. 本発明の像担持体が適用される光書込による潜像形成を行う画像形成装置の一例を模式的に示す図である。1 is a diagram schematically illustrating an example of an image forming apparatus that performs latent image formation by optical writing to which an image carrier of the present invention is applied. 本発明の像担持体の実施の形態の第２例を模式的にかつ部分的に示す横断面図である。FIG. 5 is a cross-sectional view schematically and partially showing a second example of an embodiment of an image carrier of the present invention. 本発明の像担持体の実施の形態の第３例を模式的にかつ部分的に示す横断面図である。FIG. 6 is a cross-sectional view schematically and partially showing a third example of an embodiment of an image carrier of the present invention. 本発明の像担持体の実施の形態の第４例を模式的にかつ部分的に示す横断面図である。It is a cross-sectional view schematically and partially showing a fourth example of an embodiment of an image carrier of the present invention. 本発明の像担持体の実施の形態の第５例を模式的にかつ部分的に示す横断面図である。FIG. 10 is a cross-sectional view schematically and partially showing a fifth example of an embodiment of an image carrier of the present invention. 本発明の像担持体の実施の形態の第６例を模式的にかつ部分的に示す横断面図である。It is a cross-sectional view schematically and partially showing a sixth example of an embodiment of an image carrier of the present invention.

Explanation of symbols

１…像担持体、２…基材、３…下引き層（ＵＣＬ）、４…感光層、５…電荷発生層（ＣＧＬ）、６…電荷輸送層（ＣＶＬ）、７…導電性微粒子、８…電荷注入防止層（ＣＰＬ）、９…画像形成装置、１０…書込ヘッド、１１…可撓性の基材、１２…現像装置、１２ａ…現像ローラ、１３…転写装置、１３ａ…転写ローラ、１４…帯電装置、１５…露光装置、１６…バインダー樹脂、１７…光導電性微粒子 DESCRIPTION OF SYMBOLS 1 ... Image carrier, 2 ... Base material, 3 ... Undercoat layer (UCL), 4 ... Photosensitive layer, 5 ... Charge generation layer (CGL), 6 ... Charge transport layer (CVL), 7 ... Conductive fine particle, 8 DESCRIPTION OF SYMBOLS ... Charge injection prevention layer (CPL), 9 ... Image forming apparatus, 10 ... Writing head, 11 ... Flexible base material, 12 ... Developing device, 12a ... Developing roller, 13 ... Transfer device, 13a ... Transfer roller, 14 ... charging device, 15 ... exposure device, 16 ... binder resin, 17 ... photoconductive fine particles

Claims

In a laminate type image carrier used in an image forming apparatus and having a photosensitive layer formed by laminating a charge generation layer and a charge transport layer on a conductive substrate,
In the charge transport layer, a large number of conductive fine particles are independently dispersed in the circumferential direction and the film thickness direction,
Image formation characterized in that the content of the conductive fine particles on the surface layer side of the charge transport layer is high and the content of the conductive fine particles on the substrate side of the charge transport layer is set low. An image carrier in the apparatus.

The said charge transport layer consists of the upper layer of the said surface layer side in which the said electroconductive fine particles are contained, and the lower layer by the side of the said base material in which the said electroconductive fine particles are not contained. An image carrier in an image forming apparatus.

The content rate of the electroconductive fine particles of the said charge transport layer is set so that it may become low continuously in multiple steps from the said surface layer side toward the said base material side. An image carrier in an image forming apparatus.

In a single-layer image carrier used in an image forming apparatus, in which a photosensitive layer having a charge generation function and a charge transport function is formed on a conductive substrate,
In the photosensitive layer, a large number of conductive fine particles are dispersed independently in the circumferential direction and the film thickness direction,
In the image forming apparatus, the content of the conductive fine particles on the surface layer side of the photosensitive layer is high, and the content of the conductive fine particles on the substrate side of the photosensitive layer is set low. Image carrier.

5. The image according to claim 4, wherein the photosensitive layer includes an upper layer on the surface layer side containing the conductive fine particles and a lower layer on the base material side not containing the conductive fine particles. An image carrier in the forming apparatus.

5. The image according to claim 4, wherein the content of the conductive fine particles in the photosensitive layer is set so as to decrease continuously or in a plurality of stages from the surface layer side toward the base material side. An image carrier in the forming apparatus.