Abstract: An electrophotographic toner excellent in dispersibility of a colorant, excellent in fixing property at a low temperature and having a broad fixing latitude of good offset resisting property, and a process for producing the same, as well as an electrophotographic developer and a process for forming an image using the electrophotographic toner are provided. The electrophotographic toner is provided that contains a binder resin and a colorant, in which the binder resin contains a crystalline polyester containing a carboxylic acid of two or more valences having a sulfonic acid group as a monomer component, and a process for producing the same, as well as an electrophotographic developer and a process for forming an image using the electrophotographic toner are provided.

Abstract: A toner for developing an electrostatic latent image, a process for producing the same and a process for forming an image using the same are provided. The toner is produced by a simple production process, with good reproducibility, particularly in particle size and particle size distribution. The toner is excellent in production stability, with a wide fixing region, and is also excellent in low temperature fixing property, production stability, storage stability of resin particles formed by the aggregation process, and charging property, particularly environmental stability and time-lapse stability. The toner for developing an electrostatic latent image contains a crystalline resin having a melting point as a binder resin, and at least one of an ester compound having an alkyl group having from 6 to 32 carbon atoms and a resin having a contact angle with water that is smaller than that of the crystalline resin.

Abstract: An electrophotographic toner contains a colorant and a binder resin which includes and a crystalline polyester resin as a main component. An ester density M of the crystalline polyester resin, as defined in the following Formula 1, is from 0.01 to 0.

Abstract: An electrophotographic toner excellent in dispersibility of a colorant, excellent in fixing property at a low temperature and having a broad fixing latitude of good offset resisting property, and a process for producing the same, as well as an electrophotographic developer and a process for forming an image using the electrophotographic toner are provided. The electrophotographic toner is provided that contains a binder resin and a colorant, in which the binder resin contains a crystalline polyester containing a carboxylic acid of two or more valences having a sulfonic acid group as a monomer component, and a process for producing the same, as well as an electrophotographic developer and a process for forming an image using the electrophotographic toner are provided.

Abstract: A process for preparing a stable titanyl phthalocyanine crystal showing at least one diffraction peak at a Bragg angle (2&thgr;±0.2) of 27.3° is disclosed, which comprises treating amorphous or quasi-amorphous titanyl phthalocyanine with a solvent selected from an alcohol solvent, an aromatic solvent, a mixed solvent of an alcohol solvent and an aromatic solvent, or a mixed solvent of an alcohol solvent and water. The resulting titanyl phthalocyanine exhibits high photosensitivity and excellent durability as a photoconductive material of an electrophotographic photoreceptor.

Abstract: An electrophotographic toner containing a binder resin and a colorant, wherein at the angular frequency of 1 rad/sec and 30° C., a storage elastic modulus (G′30) is at least 1×105 Pa and a loss elastic modulus (G″30) is at least 1×105 Pa; a melting point is in the temperature region of 45 and 110° C.; when a common logarithm of G′ is plotted against the temperature and G′ at melting point +20° C. is represented by G′ (Tm+20) and G′ at melting point +50° C. is represented by G′ (Tm+50) the condition of the following formula (1) is satisfied |logG′(Tm+20)−logG′(Tm+50)|≦1.5  (1); and when a common logarithm of G″ is plotted against the temperature and G″ at melting point +20° C. is represented by G″ (Tm+20) and G″ at melting point +50° C.

Abstract: A process comprising:reacting a first polymer containing at least one haloalkyl substituted styrene, with a reactive acrylate compound wherein the haloalkyl substituent is converted to an alkylacrylate ester or an alkylacrylate ester ammonium salt to form an acrylated second polymer, andirradiating said acrylated second polymer.

Abstract: An electrophotographic photoreceptor comprising a conductive substrate having thereon a photosensitive layer, the photosensitive layer containing a hydroxymetal or hydroxysilicon phthalocyanine pigment represented by formula (I) as a charge generating material, the phthalocyanine pigment having been treated with an orcanometallic compound having a hydrolyzable functional group or a hydrolysis product thereof: ##STR1## wherein Me represents A, Ga, In, Si, Ge or Sn; X representsH, C, Br or I; m represents an integer of from I to 4; and n represents 1 where Me is A, Ga or In, or 2 where Me is Si, Ge or Sn.

Abstract: Hydroxygallium phthalocyanine crystals and an electrophotographic photoreceptor comprising the same. The hydroxygallium phthalocyanine crystals contain at least one of a polar organic solvent selected from the group consisting of a compound having an amido group, a compound having a sulfoxide group, and an organic amine.

Abstract: An excellent electrographic photosensitive member having a high sensitivity, a high chargeability and a low residual potential. The electrographic photosensitive member comprises a photosensitive layer, or a photosensitive layer and an underlayer superimposed over an electroconductive support, wherein the photosensitive layer and/or the underlayer contain a chlorogallium phthalocyanine which is substituted with an electron-withdrawing group and has the following formula: ##STR1## where X represents an electron-withdrawing group such as a halogen atom and n is an integer of 2 to 4.

Abstract: Hydroxygallium phthalocyanine crystals having intense diffraction peaks at Bragg angles (2.theta..+-.0.2.degree.) of 7.5.degree., 9.9.degree., 12.5.degree., 16.3.degree., 18.6.degree., 25.1.degree. and 28.3.degree. in Cuk.alpha. characteristic X-ray diffractometry, a process for producing the same, and an electrophotographic photoreceptor containing the same are disclosed. The hydroxygallium phthalocyanine crystals are obtained by once preparing impurity-free hydroxygallium phthalocyanine having intense X-ray diffraction peaks at specific Bragg angles, followed by a solvent treatment for crystal transformation, in which the impurity-free crystals are prepared by using excess phthalocyanine ring-forming compound in the synthesis of starting gallium phthalocyanine or by removing insoluble matter from the acid paste of starting gallium phthalocyanine.

Abstract: Hydroxygallium phthalocyanine crystals having intense diffraction peaks at Bragg angles (2.theta..+-.0.2.degree.) of 7.5.degree., 9.9.degree., 12.5.degree., 16.3.degree., 18.6.degree., 25.1.degree. and 28.3.degree. in CuK.alpha. characteristic X-ray diffractometry, a process for producing the same, and an electrophotographic photoreceptor containing the same are disclosed. The hydroxygallium phthalocyanine crystals are obtained by once preparing impurity-free hydroxygallium phthalocyanine having intense X-ray diffraction peaks at specific Bragg angles, followed by a solvent treatment for crystal transformation, in which the impurity-free crystals are prepared by using excess phthalocyanine ring-forming compound in the synthesis of starting gallium phthalocyanine or by removing insoluble matter from the acid paste of starting gallium phthalocyanine.

Abstract: A hydroxygallium phthalocyanine crystal, having distinct diffraction peaks at Bragg angles (20+/-0.2.degree.) of 7.0.degree., 13.4.degree., 16.6.degree., 26.0.degree. and 26.7.degree. to CuK.alpha. characteristic X-ray in X-ray diffraction spectrum; a process for preparing the hydroxygallium phthalocyanine crystal; and a electrophotographic photoreceptor comprising the hydroxygallium phthalocyanine crystal.

Abstract: An electrophotographic photoreceptor comprising a conductive substrate having thereon a photosensitive layer, the photosensitive layer containing a hydroxymetal or hydroxysilicon phthalocyanine pigment represented by formula (I) as a charge generating material, the phthalocyanine pigment having been treated with an organometallic compound having a hydrolyzable functional group or a hydrolysis product thereof: ##STR1## wherein Me represents Al, Ga, In, Si, Ge or Sn; X represents H, Cl, Br or I; m represents an integer of from 1 to 4; and n represents 1 where Me is Al, Ga or In, or 2 where Me is Si, Ge or Sn.

Abstract: Hydroxygallium phthalocyanine crystals are produced by reacting a gallium trihalide with phthalonitrile or diiminoisoindoline in a halogenated aromatic hydrocarbon solvent, treating the resulting halogenated gallium phthalocyanine with an amide solvent, and hydrolyzing the halogenated gallium phthalocyanine. The photoreceptor exhibits stabilized electrophotographic characteristics.

Abstract: A method for preparing hydroxygallium phthalocyanine crystals wherein hydroxygallium phthalocyanine crystals having distinct diffraction peaks at 7.0.degree., 13.4.degree., 16.6.degree., 26.0.degree. and 26.7.degree. of the Bragg angle (2.theta..+-.0.2.degree.) with respect to CuK.alpha. characteristics X-ray in the X-ray diffraction spectrum are crystal-transferred by solvent treatment. The crystals after crystal-transfer have distinct diffraction peaks at (i) 7.7.degree., 16.5.degree., 25.1.degree. and 26.6.degree., (ii) 7.9.degree., 16.5.degree., 24.4.degree. and 27.6.degree., (iii) 7.0.degree., 7.5.degree., 10.5.degree., 11.7.degree., 12.7.degree., 17.3.degree., 18.1.degree., 24.5.degree., 26.2.degree. and 27.1, (iv) 7.5.degree., 9.9.degree., 12.5.degree., 16.3.degree., 18.6.degree., 25.1.degree. and 28.8.degree. or (v) 6.8.degree., 12.8.degree., 15.8.degree. and 26.0.degree. of the Bragg angle (2.theta..+-.0.2.degree. C.) with respect to CuK.alpha. characteristics X-ray in the X-ray diffraction spectrum.

Abstract: A methoxy gallium phthalocyanine compound represented by formula (I): ##STR1## wherein X represents a chlorine atom, a bromine atom, or an iodine atom; and n represents an integer of from 0 to 4; and an electrophotographic photoreceptor using the methoxy gallium phthalocyanine compound.

Abstract: A process for preparing a titanyl phthalocyanine crystal showing at least one diffraction peak at a Bragg angle (2.theta..+-.0.2) of 27.3.degree. is disclosed, which comprises dissolving or suspending titanyl phthalocyanine in concentrated sulfuric acid to form a solution or a slurry and diluting the solution or slurry with an alcohol solvent, an aromatic solvent, a mixed solvent of an alcohol solvent and water, a mixed solvent of an aromatic solvent and water, or a mixed solvent of an alcohol solvent and an aromatic solvent with or without water thereby to precipitate a crystal, and, if desired, treating the precipitated crystal with an alcohol solvent, an aromatic solvent, a mixed solvent of an alcohol solvent and an aromatic solvent or a mixed solvent of an alcohol solvent and/or an aromatic solvent and water. The resulting titanyl phthalocyanine crystal exhibits high photosensitivity and excellent durability as a photoconductive material of an electrophotographic photoreceptor.

Abstract: A hydroxygallium phthalocyanine crystal, having distinct diffraction peaks at Bragg angles (2.theta.+/-0.2.degree.) of 7.0.degree., 13.4.degree., 16.6.degree., 26.0.degree. and 26.7.degree. to CuK.alpha. characteristic X-ray-in X-ray diffraction spectrum; a process for preparing the hydroxygallium phthalocyanine crystal; and a electrophotographic photoreceptor comprising the hydroxygallium phthalocyanine crystal.

Abstract: A process for preparing hydroxygallium phthalocyanine comprising reacting a gallium trialkoxide and phthalonitrile or diiminoisoindoline in an alcohol solvent, preferably an alcohol having a boiling point of not lower than 150.degree. C., such as ethylene glycol, and hydrolyzing the resulting gallium phthalocyanine, preferably in an aqueous solution of an acid, such as sulfuric acid. The resulting hydroxygallium phthalocyanine exhibits stable electrophotographic characteristics, particularly photosensitivity, charging properties, and a dark decay rate.