Abstract: The present invention relates to a titanyl phthalocyanine crystal having excellent storage stability of coating solution, to satisfy that (a) the crystal does not have a peak of a change in temperature except for a peak associated with evaporation of adsorbed water in differential scanning calorimetry or that (b) the crystal recovered after dipping in an organic solvent for 24 hours at least a maximum peak at a Bragg angle 2&thgr;±0.2°=27.2° and has no peak at 26.2° in a CuK &agr; characteristic X-ray diffraction spectrum, and a method of producing the same; and an electrophotosensitive material using the above crystal, and a method of producing the same.

Abstract: Disclosed are image forming apparatus [1] which comprises removing a toner remained on the surface of the rotatable image carrier by cleaning means after going through developing means and transferring means; said cleaning means has an elastic blade and is contacted with the surface of the image carrier at a contact pressure within 8 to 20 g/cm, and a press-contact angle of the elastic blade of 12 to 30°; and said image carrier is an organic photosensitive material having a photosensitive layer made of a binder resin containing an electric charge generating material and an electric charge transferring material; and image forming apparatus [2], comprising a single-layer type photosensitive layer made of a binder resin containing an electric charge generating material, an electron transferring material and a hole transferring material, and the solid content of the binder resin is within 50 to 70 wt % of the whole solid content in the photosensitive layer and, a pair of paper transporting

Abstract: Disclosed is a single-layer type electrophotosensitive material which comprises a conductive substrate, and a photosensitive layer made of a binder resin containing at least an electric charge generating material and an electric charge transferring material formed on said conductive substrate, wherein said photosensitive layer contains a polyalkylene glycol compound represented by the formula [1]: A1—O—[(CH2)m—O]n—A2 wherein A1 and A2 are the same or different and represent an alkyl or aryl group having 1 to 50 carbon atoms, or a group: —CO—R10 (R10 represents an alkyl or aryl group having 1 to 50 carbon atoms), m represents an integer of 1 to 5, and n represents an integer of 2 to 100, which is superior in wear resistance, sensitivity and gas resistance.

Abstract: Disclosed is a single-layer type electrophotosensitive material comprising a conductive substrate and a photosensitive layer made of a binder resin containing at least an electric charge generating material and an electric charge transferring material, which is formed on the conductive substrate, wherein an oxygen transmission rate of the binder resin is not more than 35 cc·mm/m2·day·atom, wherein it is preferred that a mobility at an electric field strength of 5×105 V/cm of the hole transferring material is not less than 5×10−6 cm2/V/sec and a solid content of the electric charge transferring material is not less than 30% by weight and not more than 50% by weight based on the whole solid content; said electrophotosensitive material has good ozone resistance and does not cause defects such as image black belt due to lowering of the charge capability, an ozone of which is 5.0 ppm at most, and is also superior in sensitivity and wear resistance.

Abstract: Disclosed is a single-layer type electrophotosensitive material which comprises a conductive substrate, and a photosensitive layer made of a binder resin containing at least an electric charge generating material and an electric charge transferring material formed on said conductive substrate, wherein said photosensitive layer contains a polyalkylene glycol compound represented by the formula [1]:

Abstract: Disclosed are a phthalocyanine crystal in which an organic acceptor compound is associated with a phthalocyanine molecule, wherein said organic acceptor compound has a reduction potential to a reference electrode (Ag+/Ag) is not less than −1.5 V and not more than −0.5 V, and an electrophotosensitive material containing said phthalocyanine crystal as an electric charge generating material, which exhibits sufficient photosensitivity even in high-speed image forming apparatuses.

Abstract: A single-layer type electrophotosensitive material comprising a conductive substrate and a photosensitive layer made of a binder resin containing at least an electric charge generating material and a hole transferring material and an electron transferring material as an electric charge transferring material, which is formed on the conductive substrate, characterized in that the binder resin contains a polycarbonate resin having a repeating structural unit represented by the general formula [1] and the solid content of the hole transferring material and the electron transferring material is not less than 30% by weight and not more than 50% by weight relative to the entire solid content, exhibits good wear resistance with respect to the photosensitive layer and is also superior in durability.

Abstract: The present invention relates to a novel stilbene derivative, which is a stilbene compound wherein molecular structures of triphenylamino groups located at both sides of a benzene ring in a molecular center are unsymmetric, and an electrophotosensitive material having high sensitivity and improved repeatability, comprising a conductive substrate and a photosensitive layer formed on the substrate, the photosensitive layer containing the derivative.

Abstract: Disclosed are a stilbene derivative having the general formula (1) and a production thereof, and the electrophotosensitive material comprises a conductive substrate and a photosensitive layer provided on the conductive substrate, wherein the photosensitive layer contains a stilbene derivative (1): wherein R1 and R3 represent an alkyl group which may have a substituent, an alkoxy group which may have a substituent or the like, and R2 and R4 represent a hydrogen atom, an alkyl group which may have a substituent or the like.

Abstract: The present invention provides a novel stilbene derivative represented by the general formula (1): ##STR1## wherein R.sup.1 and R.sup.3 represent an alkyl group, an aryl group, an aralkyl group or an alkoxy group which are optionally substituted; and R.sup.2 and R.sup.4 represent a hydrogen atom, an alkyl group or an alkoxy group which are optionally substituted, provided that when the substitution position of R.sup.2 and R.sup.4 is the 4-(para) position, R.sup.2 and R.sup.4 are hydrogen atoms, a method for producing the same and use thereof. The above stilbene derivative (1) is useful as an electric charge transferring material, particularly hole transferring material.

Abstract: The present invention provides an electrophotosensitive material comprising a photosensitive layer containing a m-phenylenediamine compound represented by the general formula (1): ##STR1## wherein R.sup.1A and R.sup.1B are the same or different and indicate an alkyl group; and R.sup.1C, R.sup.1D, R.sup.1E and R.sup.1F are the same or different and indicate a hydrogen atom or an alkyl group, which has high sensitivity and issuperior in stability to strong light, durability and heat resistance, and an image forming method capable of realizing more higher speed and more larger energy saving than the prior art.

Abstract: The present invention provides a naphthoquinone derivative represented by the general formula (I): ##STR1## wherein R.sup.1 and R.sup.2 are as defined in the specification. An electrophotosensitive material containing this naphthoquinone derivative as an electron transferring material has high sensitivity.

Abstract: The present invention provides a naphthoquinone derivative represented by the general formula (I): ##STR1## wherein R.sup.1 and R.sup.2 are as defined in the specification. An electrophotosensitive material containing this naphthoquinone derivative as an electron transferring material has high sensitivity.

Abstract: The present invention provides a novel tryptanthrine derivative represented by a general formula: ##STR1## wherein R.sup.1 is an oxygen atom, or group represented by a formula: ##STR2## wherein R.sup.2A and R.sup.2B are the same or different and indicate a hydrogen atom, a cyano group, an acyl group, an alkoxycarbonyl group or an alkyl group, provided that R.sup.2A and R.sup.2B are not hydrogen atoms simultaneously; andR.sup.3A, R.sup.3B, R.sup.3C, R.sup.3D, R.sup.4A, R.sup.4B, R.sup.4C and R.sup.4D are the same or different and indicate a hydrogen atom or an alkyl group which may have a substituent, provided that when R.sup.1 is an oxygen atom, any one of R.sup.3A through R.sup.4D is a cyano group.Such a tryptanthrine derivative has an excellent electron transport capability to be suitably used for the electrophotosensitive material.

Abstract: The present invention provides a tryptoanthrinimine derivative represented by the general formula (Y): ##STR1## wherein R.sup.A to R.sup.M are as defined. Such a derivative of the general formula (Y) is superior in electron transferring capability. Accordingly, an electrophotosensitive material comprising a photosensitive layer containing this derivative (Y) is superior in sensitivity.