Mitsubishi Chemical Corporation

Hiroaki Takamura

Teruyuki Mitsumori

Kozo Ishio

Shiho Sano

Shiro Yasutomi

Masakazu Sugihara

Yumi Hirabaru

Tadashi Mizushima

Masaya Oota

Takeshi Oowada

Mitsuo Wada

Kazutaka Ida

Teruki Senokuti

Masayuki Hiroi

Teruki Senokuchi

Mamoru Nozomi

Masaya Ota

Hiroe Fuchigami

Yuka Nagao

Takahiro Choda

Tomoko Nakagawa

Yasunori Kawai

Itaru Ogawa

Takuya Nishikiori

Masami Tsurumori

Yuzo Kaneko

Takeshi Owada

Shunichirou Kurihara

Tooru Uenaka

Provided is an excellent phthalocyanine crystal having high sensitivity and little fluctuation in sensitivity for a humidity change in a use environment and applicable to the martial for solar battery, electronic paper, electrophotographic photoreceptor, etc. Namely, phthalocyanine crystal obtained by bringing a phthalocyanine crystal precursor into contact with an aromatic aldehyde compound to convert the crystal form. Also, provided is an electrophotographic photoreceptor that not only exhibits high sensitivity but also has little fluctuation in sensitivity for a humidity change in a use environment. Further, provided is an electrophotographic photoreceptor cartridge and an image-forming device, both of which can produce a stable quality images for a humidity change in a use environment by using the electrophotographic photoreceptor.

Phthalocyanine crystal, and electrophotographic photoreceptor, electrophotographic photoreceptor cartridge and image-forming device using the same

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

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

It is to provide a sheet-shaped electrophotographic photoreceptor which has an uncoated area, is good in mechanical adhesiveness between the photosensitive layer and the sheet-shaped conductive substrate but excellent ease of peeling with a solvent, and is further good in electrical properties. The electrophotographic photoreceptor comprises a sheet-shaped conductive substrate and a photosensitive layer provided thereon, wherein the electrophotographic photoreceptor contains a photosensitive layer-uncoated area within the sheet surface, and the photosensitive layer contains a copolycarbonate resin having an extremely restricted specific structure.

Electrophotographic photoreceptor and image-forming apparatus

To provide an electrophotographic photoreceptor excellent in electric characteristics and various characteristics, capable of forming a uniform photosensitive layer and excellent in repetitive characteristics, an image forming apparatus using it and an electrophotgraphic cartridge. A lamination type electrophotographic photoreceptor comprising an electroconductive substrate and a photosensitive layer formed thereon, characterized in that the photosensitive layer contains a compound represented by the following formula (1), the ratio of the weight of the compound represented by the formula (1) to the weight content of all binder resins contained in the photosensitive layer is from 0.15 to 0.6, and the weight of the compound represented by the formula (1) is maximum among all charge transport materials: wherein each of Ar, Arand Aris an aryl group which may have a substituent, each of Arand Arwhich are independent of each other, is an arylene group which may have a substituent, and each of nand nwhich are independent of each other, is an integer of from 1 to 3.

Electrophotographic photosensitive body, image-forming device using same and 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

To realize an electrophotographic photoreceptor excellent in abrasion resistance, the photosensitive layer of the photoreceptor comprises a polyester resin containing a repeating structural unit represented by the formula (1) and a hydrazone compound. (In the formula (1), Arto Areach represents, independently of each other, an arylene group which may have a substituent. Xrepresents a bivalent group (including a single bond) and Xrepresents a bivalent group (including a single bond) with 3 or less atoms.)

Electrophotographic photoreceptor, and image forming device and electrophotographic photoreceptor cartridge using the same member cartridge

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).

An electrophotographic copying method, which comprises conducting each process of at least charging, exposing to light, developing and transferring, characterized in that the photoreceptor has at least an undercoat layer and a photosensitive layer on an electroconductive substrate, wherein the undercoat layer contains a semiconductive material having a band gap of at least 2.2 eV and a binder resin, the photosensitive layer contains at least a phthalocyanine compound as a charge-generation material, and image-formation is carried out from the first revolution of the photoreceptor.

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Odawara, Japan

Hiroaki Takamura