Abstract: A method of producing a heat-resistant electrically charged fluororesin material is provided. The method comprises the steps of providing a fluorine-containing resin material; irradiating the fluorine-containing resin material with ionizing radiation at a temperature not lower than a crystalline melting point of the fluorine-containing resin material in absence of oxygen, thereby causing crosslinking in the fluorine-containing resin material to change the fluorine-containing resin material into a heat-resistant fluororesin material; and, electrifying the heat-resistant fluororesin material to form a heat-resistant electrically charged fluororesin material. The method may further comprises the step of heating the material following the step of electrifying. The successive steps of electrifying and heating are repeatedly conducted more than one time.

Abstract: A ferroelectric element comprising a ferroelectric material containing at least two metals, the ferroelectric element having been produced by a process including a sol-gel process in the presence of a thickener and/or an association preventive from aqueous solutions of respective salts of the metals. The ferroelectric element is advantageous in that the handling of starting compounds and the production of the ferroelectric element are easy, the storage stability of the starting compound solution is good, the cost is low, the ferroelectric element can be formed as a thin layer, particles on the surface of the thin layer are fine and dense, and, hence, the surface smoothness is good. The ferroelectric element is excellent also in piezoelectric properties and therefore can be advantageously used as a piezoelectric element in a piezoelectric ink jet head.

Abstract: A nozzle plate for an ink-jet head used in an ink-jet type recorder, comprising a flat plate member which defines an ink blow-out surface on one main surface thereof and has a plurality of ink blow-out nozzles penetrating at predetermined positions, wherein said ink blow-out surface and portions on the inner surfaces of said ink blow-out nozzles neighboring said ink blow-out surface, have, at least partly, an ink-repelling layer of a fluorine-contained resin-containing electrolytic or non-electrolytic composite plating. Upon forming a particular ink-repelling layer on the nozzle plate, it is possible to prevent the ink from staying adhered on the peripheries of the nozzles after the ink droplets are blown out from the nozzles, permitting the ink droplets to fly stably toward the recording medium.

Abstract: An ink jet head, for use in an ink jet recording apparatus, comprising an ink chamber, a member constituting the ink chamber being made of a plastic material having a surface possessing a hydrophilic nature imparted by surface treatment, for introducing a polar group, selected from the group consisting of acid treatment, ultraviolet light-ozone irradiation, and oxygen plasma treatment, and a process for producing the same. When the ink jet head is used in an ink jet printer using a water-base ink, the wettability of an ink flow passage within the head is good and, in addition, the good wettability can be stably maintained, permitting a high print quality to be ensured for a long period of time.

Abstract: A ferroelectric element comprising a ferroelectric material containing at least two metals, the ferroelectric element having been produced by a process including a sol-gel process in the presence of a thickener and/or an association preventive from aqueous solutions of respective salts of the metals. The ferroelectric element is advantageous in that the handling of starting compounds and the production of the ferroelectric element are easy, the storage stability of the starting compound solution is good, the cost is low, the ferroelectric element can be formed as a thin layer, particles on the surface of the thin layer are fine and dense, and, hence, the surface smoothness is good. The ferroelectric element is excellent also in piezoelectric properties and therefore can be advantageously used as a piezoelectric element in a piezoelectric ink jet head.

Abstract: A ferroelectric element, having a ferroelectric material containing at least two metals, the ferroelectric element having been produced by a process including the steps of: providing alkoxides of the respective metals as starting compounds; hydrolyzing the metal alkoxides in the presence of a catalytic amount of a protonic acid to increase the molecular weight; and adding a film-forming polymer material to the sol-like solution prepared in the step of increasing the molecular weight to prepare a sol-like ferroelectric precursor solution. The ferroelectric element can be formed in a thick film form without creating any cracks. It can be advantageously used as a piezoelectric element in a piezoelectric ink jet head.

Abstract: A ferroelectric element, including a ferroelectric material containing at least two metals, the ferroelectric element having been produced by a process including the steps of: providing alkoxides of the respective metals as starting compounds; hydrolyzing the metal alkoxides in the presence of a catalytic amount of a protonic acid to increase the molecular weight; and adding a film-forming polymer material to the sol-like solution prepared in the step of increasing the molecular weight to prepare a sol-like ferroelectric precursor solution. The ferroelectric element can be formed in a thick film form without creating any cracks. It can be advantageously used as a piezoelectric element in a piezoelectric ink jet head.

Abstract: A ferroelectric element comprising a ferroelectric material containing at least two metals, the ferroelectric element having been produced by a process including a sol-gel process in the presence of a thickener and/or an association preventive from aqueous solutions of respective salts of the metals. The ferroelectric element is advantageous in that the handling of starting compounds and the production of the ferroelectric element are easy, the storage stability of the starting compound solution is good, the cost is low, the ferroelectric element can be formed as a thin layer, particles on the surface of the thin layer are fine and dense, and, hence, the surface smoothness is good. The ferroelectric element is excellent also in piezoelectric properties and therefore can be advantageously used as a piezoelectric element in a piezoelectric ink jet head.

Abstract: A ferroelectric element comprising a ferroelectric material containing at least two metals, the ferroelectric element having been produced by a process including a sol-gel process in the presence of a thickener and/or an association preventive from aqueous solutions of respective salts of the metals. The ferroelectric element is advantageous in that the handling of starting compounds and the production of the ferroelectric element are easy, the storage stability of the starting compound solution is good, the cost is low, the ferroelectric element can be formed as a thin layer, particles on the surface of the thin layer are fine and dense, and, hence, the surface smoothness is good. The ferroelectric element is excellent also in piezoelectric properties and therefore can be advantageously used as a piezoelectric element in a piezoelectric ink jet head.

Abstract: A ferroelectric element comprising a ferroelectric material containing at least two metals, the ferroelectric element having been produced by a process including a sol-gel process in the presence of a thickener and/or an association preventive from aqueous solutions of respective salts of the metals. The ferroelectric element is advantageous in that the handling of starting compounds and the production of the ferroelectric element are easy, the storage stability of the starting compound solution is good, the cost is low, the ferroelectric element can be formed as a thin layer, particles on the surface of the thin layer are fine and dense, and, hence, the surface smoothness is good. The ferroelectric element is excellent also in piezoelectric properties and therefore can be advantageously used as a piezoelectric element in a piezoelectric ink jet head.

Abstract: A ferroelectric element, having a ferroelectric material containing at least two metals, the ferroelectric element having been produced by a process including the steps of: providing alkoxides of the respective metals as starting compounds; hydrolyzing the metal alkoxides in the presence of a catalytic amount of a protonic acid to increase the molecular weight; and adding a film-forming polymer material to the sol-like solution prepared in the step of increasing the molecular weight to prepare a sol-like ferroelectric precursor solution. The ferroelectric element can be formed in a thick film form without creating any cracks. It can be advantageously used as a piezoelectric element in a piezoelectric ink jet head.

Abstract: A method of modifying a pigment which comprises dissolving the pigment into sulfuric acid and then mixing water with the pigment-sulfuric acid solution. The modified pigment is excellent in achieving uniform dispersion and has a small particle size. An electrophotographic photoreceptor containing the modified pigment as the organic photoconductor has uniform sensitivity, sufficient charge acceptance and small dark decay.

Abstract: An electrophotographic photoreceptor comprises an .alpha.-form copper phthalocyanine composition, which is obtained by treating a copper tetranitrophthalocyanine and copper phthalocyanine simultaneously to convert the crystalline form into .alpha.-form, and a photoconductive squarylium compound as the photoconductive material, and the ratios of the copper tetranitrophthalocyanine and the squarylium compound to the .alpha.-form copper phthalocyanine composition are limited to a particular range. The photoreceptor has a high photosensitivity and an excellent durability.

Abstract: A crude naphthoquinone produced by an oxidation of naphthalene is purified by a reduced pressure distillation of a crude 1,4-naphthoquinone having an acid content of less than 5 equivalent % calculated as monobasic acid and the crude naphthoquinone is preferably treated by an oxidation of oxidizable impurities.