Abstract: A method of manufacture an ink jet head in which an ink is jetted from a nozzle hole by applying an electric voltage to an electrode so as to deform ink chambers divided by a partition wall. The method includes the steps of providing plural piezoelectric base plates having polarization side by side on a first non-piezoelectric plate, forming plural grooves for the ink chambers on the piezoelectric base plates and at connecting portions where each edge of the plural piezoelectric base plates provided side by side comes to face other edge; and mounting a second non-piezoelectric base plate on the plural piezoelectric base plates as so to cover the plural grooves so that the ink chambers divided by the partition wall are formed.

Abstract: A method of processing a nozzel plate on which a plurality of nozzel holes for jetting ink are provided, comprises steps of: bringing one side of the nozzele plate in contact with a processing liquid; bringing the other side of the nozzel plate in contact with a gas phase; and forming a boundry surface between the processing liquid and the gas phase so that a film layer is formed on the one side of the nozzel plate by the processing liquid.

Abstract: An ink jet head to jet ink from a nozzle hole by applying an electric voltage to an electrode so as to deform a shape of a space forming an ink chamber, comprises two piezoelectric base plates given polarization; two non-piezoelectric base plates, wherein the ink chamber is formed by being enclosed by the two piezoelectric base plates facing each other and the two non-piezoelectric base plates facing each other; each of the two piezoelectric base plates comprising at least two lamination layers made of a piezoelectric material, wherein the two lamination layers are laminated such that the laminated surface is substantially parallel to the non-piezoelectric base plates and polarizing directions of the two lamination layers are opposite to each other; and electrodes provided on surfaces of the piezoelectric base plates and the non-piezoelectric base plates, wherein the surfaces face the ink chamber.

Abstract: An extrusion-type coating apparatus for performing a uniform coating on a web by equalizing a flow rate distribution of a coating material along the widthwise direction of the web. The apparatus has a slit in a coating head to pass the coating material from the bottom of the slit to an opening of the same opened on a surface portion of the coating head, a feeder to feed the web on the surface portion in a direction from a front edge to a rear edge of the opening of the slit and a restricting member to restrict a gap of the slit by an insertion of the restricting member into the slit. The restricting member has a thickness pattern along its length so as to equalize the flow rate of the coating material along the length of the slit.

Abstract: A magnetic recording medium is disclosed which comprises a first magnetic layer on a nonmagnetic support and a second magnetic layer on the first magnetic layer.The first magnetic layer contains A parts by weight of at least one of Si and Al per 100 parts by weight of magnetic materials, and the second magnetic layer contains B parts by weight of at least one of Si and Al per 100 parts by weight of magnetic materials, wherein A is smaller than B.This magnetic recording medium is characterized in that: the magnetic recording medium does not stain the conveyance rollers in the manufacturing process; problems which tend to occur when running conventional tapes are greatly reduced; and it is suitable for use as a video tape.

Abstract: An extruder for coating magnetic layers onto electro-magnetic recording tape is disclosed, which is provided with two reservoirs and two outlet channels so as to permit simultaneous coating of two layers. The two outlet channels meet at an angle and merge into a single outlet channel, which extrudes the two layers between a front edge and a rear edge. The front edge has a shape of curvature, and the rear edge protrudes beyond a tangential line drawn from the end of the front edge curvature. The extruder is capable of producing double layered magnetic tape with or without a mixed zone between layers.

Abstract: A coating apparatus having a first slot between its front and center edges and a second slot between its center and back edges, wherein a coating solution is extruded continuously from each of the slots onto the surface of a flexible support running continuously along the edge surfaces of the front, center, and back edges in that order.The front edge surface has a straight-line portion on at least the terminal end portion of the front edge so that the straight-line portion extends along the direction of movement of the support and is not longer than one mm, and at least one portion of the center and back edge surfaces protrudes from the extension line of the straight-line toward the support.The coating apparatus is suitable for preparing magnetic recording media.

Abstract: The invention provides an apparatus for coating a solution on a tape-shaped flexible support which is moved so as to run along a top surface of coating head. The coating head is slitted so as to form a front edge surface, a back edge surface in order in the moving direction of the flexible support, and a slit therebetween so that the solution is extruded through the slit of the coating head to the flexible support. In this configuration, at least a part of the back edge surface projects beyond the tangent line at the downstream end of the front edge surface.

Abstract: A magnetic recording medium having plural magnetic layers is disclosed. The uppermost magnetic layer contains an abrasive with an average particle diameter of not more than 0.3 .mu.m, and a magnetic layer other than the uppermost magnetic layer contains an abrasive with an average particle diameter of not less than 0.3 .mu.m. The medium is improved in the electromagnetic conversion characteristics and sliding noise.

Abstract: Disclosed is a coating head for coating a solution on a flexible support which is moved so as to run along a coating surface of the coating head. The coating surface is slitted so as to form a front face, a back face in order in the moving direction of the flexible support, and a slit therebetween so that the coating head extrudes the solution through the slit to the flexible support. The front face has an arc surface with a curvature radius of r.sub.1 and the back face wholly forms an arc surface with a curvature radius of r.sub.2 in the following equations 3 mm <r.sub.2 < 20 mm and 1 mm <r.sub.1 <r.sub.2 /2. Further, at least a part of the back face projects beyond the tangent line at the downstream end of the front face.

Abstract: An improved method of coating one or more layer of a coating liquid onto a moving substrate from a coating hopper wherein coating bead of the coating liquid is formed and a part of the bead is formed at a side of entering of the substrate with respect to an efflux end of the coating hopper, and an end of the part of the bead being in contact with the coating hopper is held at a fixed position.

Abstract: A coating apparatus is disclosed. The apparatus comprises a coating head having a slide face along which a coating liquid flows down and a roll moving a continuous web downwardly. The slide face and the roll define a space for forming a sustained liquid mass therein. The coating head has a bottom face which is provided with a groove in the proximity of and substantially parallelly to the slide face whereby a thin liquid film is formed on the web at high speed.