Mitsubishi Chemical Corporation

Kozo Ishio

Teruyuki Mitsumori

Hiroaki Takamura

Shiro Yasutomi

Shiho Sano

Masakazu Sugihara

Yumi Hirabaru

Masaya Oota

Takeshi Oowada

Hiroe Fuchigami

Teruki Senokuti

Yasunori Kawai

Shuichi Ikeda

Yohei Matsuoka

Teruki Senokuchi

Tetsuo Murayama

Tetsuo Ozawa

Mamoru Nozomi

Masaya Ota

Takuya Nishikiori

Yuzo Kaneko

Takeshi Owada

Hiroe Kizaki

An end member is disposed in an end portion of a columnar rotating body, comprising: a shaft member; and a bearing member which holds the shaft member, wherein the shaft member comprises: a rotating shaft; and a rotating force receiving portion, and wherein at least one of the shaft member and the bearing member has a mechanism where the rotating force receiving portion moves also in a shaft line direction without be inclined by a movement of the rotating force receiving portion in a direction orthogonal to the shaft line direction or by a rotation of the rotating force receiving portion around a shaft line.

End member, photoreceptor drum unit, and process cartridge

An end member disposed in an end portion of a columnar rotating body, comprising: a shaft member; and a bearing member to which the shaft member is attached, wherein the bearing member includes a rotating force transmission pin, a tubular body, and a pin holding portion, the shaft member includes a rotating shaft, a rotating force receiving portion, and a base end portion.

A method of forming an image including an electrophotographic photoreceptor and a toner, wherein a photosensitive layer in the electrophotographic photoreceptor includes an undercoat layer including metal oxide particles, a charge generation layer including hydroxygallium phthalocyanine, and a charge transport layer, and the toner contains toner matrix particles formed in an aqueous medium; the toner has a volume median diameter (Dv50) of from 4.0 &#x3bc;m to 7.0 &#x3bc;m; and the relationship between the volume median diameter (Dv50) and the percentage in number (Dns) of toner particles having a particle diameter of from 2.00 &#x3bc;m to 3.56 &#x3bc;m satisfies&#x2014;0.0517EXP(22.4/Dv50)&#x2266;Dns&#x2266;0.233EXP(17.3/Dv50) where Dv50 is the volume median diameter (&#x3bc;m) of the toner, and Dns is the percentage in number of toner particles having a particle diameter of from 2.00 &#x3bc;m to 3.56 &#x3bc;m.

Method of image forming with a photoreceptor and toner

A coating fluid for photosensitive-layer formation having high productivity and stability and a process thereof are provided. Also provided are a high-performance electrophotographic photoreceptor and an image-forming apparatus which are capable of forming high-quality images even in various use environments and are less apt to cause image defects such as black spots or color spots. The objects are accomplished with a process for producing a coating fluid which is for forming a photosensitive layer of an electrophotographic photoreceptor and comprises a charge-generating material and a binder resin, wherein a dispersing medium having an average particle diameter in the range of from 1.0 &#x3bc;m to 350 &#x3bc;m is used as a dispersing medium for dispersing the charge-generating material in the coating fluid for photosensitive-layer formation. The coating fluid for photosensitive-layer formation produced by this process is preferable as a photosensitive layer of an electrophotographic photoreceptor. The charge-generating material preferably comprises a phthalocyanine pigment and the phthalocyanine pigment in the coating fluid preferably has a 50% cumulative particle diameter (D50) of 0.13 &#x3bc;m or smaller as determined by a dynamic light scattering method.

Coating fluid for photosensitive-layer formation, process for producing the same, photoreceptor produced with the coating fluid, image-forming apparatus employing the photoreceptor, and electrophotographic cartridge employing the photoreceptor

An object of the invention is to provide a toner which is effective in improving image quality while inhibiting white-background fouling, residual-image phenomenon (ghost), blurring (suitability for solid printing), and the like that occur depending on the proportion of a fine powder having a particle diameter not larger than a specific value, and which has satisfactory removability in cleaning, mitigates problems concerning fouling, etc. in long-term use even on a high-speed printer, and attains excellent image stability. Another object is to provide an image-forming apparatus and a toner cartridge each employing the toner. The invention provides a toner for electrostatic-image development satisfying all of the following (1) to (4) or a toner for electrostatic-image development which is a toner containing a charge control agent and satisfying all of the following (5) to (7). The invention further provides an image-forming apparatus and a toner cartridge each employing the toner. (1) To have a volume-median diameter (Dv50) of from 4.0 &#x3bc;m to 7.5 &#x3bc;m. (2) To have an average degree of circularity of 0.93 or higher. (3) A volume-median diameter (Dv50) of the toner and population number % of toner particles having a particle diameter of from 2.00 &#x3bc;m to 3.56 &#x3bc;m (Dns) in the toner satisfy the relationship Dns&#x2266;0.233 EXP(17.3/Dv50). (4) To have a coefficient of variation in number of 24.0% or lower. (5) To have a volume-median diameter (Dv50) of from 4.0 &#x3bc;m to 7.5 &#x3bc;m. (6) A volume-median diameter (Dv50) of the toner and population number % of toner particles having a particle diameter of from 2.00 &#x3bc;m to 3.56 &#x3bc;m (Dns) in the toner satisfy the relationship Dns&#x2266;0.233 EXP(17.3/Dv50). (7) When the charge control agent on the toner surface is cleaned, the resultant depressions have an average diameter of 500 nm or smaller.

Toners for electrostatic-image development, cartridge employing toner for electrostatic-image development, and image-forming apparatus

A method of forming an image on a substrate with an electrophotographic photoreceptor and a toner, a photosensitive layer of the electrophotographic photoreceptor contains a resin having a structural unit represented by the following formula (A) the toner containing toner matrix particles formed in an aqueous medium; the toner has a volume median diameter (Dv50) of from 4.0 &#x3bc;m to 7.0 &#x3bc;m; and the relationship between the volume median diameter (Dv50) and the percentage in number (Dns) of toner particles having a particle diameter of from 2.00 &#x3bc;m to 3.56 &#x3bc;m satisfies following formula (1)&#x2266;0.233EXP(17.3/50)&#x2003;&#x2003;(1).

Image forming apparatus

Provided is a coating liquid for forming an undercoat layer of an electrophotographic photoreceptor exhibiting high stability. In the coating liquid for forming an undercoat layer of an electrophotographic photoreceptor containing metal oxide particles and a binder resin, the metal oxide particles have a cumulative volume average diameter Dof 0.1 &#x3bc;m or less and a volume particle size distribution width index SD satisfying the following Expression (1) which are measured by a dynamic light-scattering method in the coating liquid for forming an undercoat layer,0.010&#x2266;SD&#x2266;0.040&#x2003;&#x2003;(1)where SD=(DD)/2, where Drepresents the particle diameter (&#x3bc;m) at a point of 84% in the cumulative volume particle size distribution curve, and Drepresents the particle diameter (&#x3bc;m) at a point of 16% in the cumulative volume particle size distribution curve.

Coating liquid for forming undercoat layer, method for preparing coating liquid for forming undercoat layer, electrophotographic photoreceptor, image-forming apparatus, and electrophotographic cartridge

An electrophotographic photoreceptor having high sensitivity and hardly affected by the transfer in an electrophotographic process is provided. The electrophotographic photoreceptor includes an undercoat layer containing metal oxide particles and a binder resin and a photosensitive layer disposed on the undercoat layer, wherein the metal oxide particles have a volume average particle diameter of 0.1 &#x3bc;m or less and a 90% cumulative particle diameter of 0.3 &#x3bc;m or less which are measured by a dynamic light-scattering method in a liquid of the undercoat layer dispersed in a solvent mixture of methanol and 1-propanol at a weight ratio of 7:3, and the photosensitive layer contains a binder resin having an ester bond.

Electrophotographic photoreceptor, image-forming apparatus, and electrophotographic cartridge

An electrophotographic photoreceptor having high sensitivity and low residual potential is provided. The electrophotographic photoreceptor includes an undercoat layer containing metal oxide particles and a binder resin on an electroconductive substrate, and a photosensitive layer disposed on the undercoat layer, wherein the metal oxide particles have a volume average particle diameter of 0.1 &#x3bc;m or less and a 90% cumulative particle diameter of 0.3 &#x3bc;m or less which are measured by a dynamic light-scattering method in a liquid of the undercoat layer dispersed in a solvent mixture of methanol and 1-propanol at a weight ratio of 7:3; and the photosensitive layer contains crystalline phthalocyanine showing at least one distinct main diffraction peak at a Bragg angle (2&#x3b8;&#xb1;0.2&#xb0;) of 27.0&#xb0; to 29.0&#xb0; in an X-ray diffraction spectrum.

An image forming apparatus comprising an electrophotographic photoreceptor having a photosensitive layer on an electroconductive substrate, and a toner for developing an electrostatic charge image, wherein the photosensitive layer of the electrophotographic photoreceptor contains a phthalocyanine obtained via an acid paste step; the toner for developing an electrostatic charge image is a toner for developing an electrostatic charge image containing toner matrix particles formed in an aqueous medium; the toner has a volume median diameter (Dv50) of from 4.0 &#x3bc;m to 7.0 &#x3bc;m; and the relationship between the volume median diameter (Dv50) and the percentage in number (Dns) of toner particles having a particle diameter of from 2.00 &#x3bc;m to 3.56 &#x3bc;m satisfies the following formula (1):&#x2266;0.233 EXP(17.3/50)&#x2003;&#x2003;(1).

To provide an image forming apparatus which is able to improve image quality while suppressing soiling of image white parts, scattering in the apparatus, streaks, fading, etc. due to non-uniformity in the particle size distribution of a toner or mismatching between a toner and a photoreceptor, and which has good cleaning properties, and even when a high speed printing machine is used, is able to reduce a problem of soiling, etc. in long-term use and provide excellent image stability. An image forming apparatus comprising an electrophotographic photoreceptor having a photosensitive layer on an electroconductive substrate, and a toner for developing an electrostatic charge image, wherein the photosensitive layer of the electrophotographic photoreceptor contains a phthalocyanine obtained via an acid paste step; the toner for developing an electrostatic charge image is a toner for developing an electrostatic charge image containing toner matrix particles formed in an aqueous medium; the toner has a volume median diameter (Dv50) of from 4.0 &#x3bc;m to 7.0 &#x3bc;m; and the relationship between the volume median diameter (Dv50) and the percentage in number (Dns) of toner particles having a particle diameter of from 2.00 &#x3bc;m to 3.56 &#x3bc;m satisfies the following formula (1):&#x2266;0.233 EXP(17.3/50)&#x2003;&#x2003;(1).

Electrophotographic photoreceptor

An electrophotographic photoreceptor of the present invention comprises on a conductive support a photosensitive layer containing an arylamine hydrazone compound which has --O--A substituent on aryl moiety. The electrophotographic photoreceptor of the present invention exhibits a very high sensitivity and a lowering in residual potential. It is excellent in durability.

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Odawara, Japan

Kozo Ishio