Abstract: An ink jet print head includes a cavity plate having a plurality of nozzles and a plurality of pressure chambers communicating with the respective nozzles, and a plate-like piezoelectric actuator, in which piezoelectric sheets having a plurality of electrodes formed at positions with respect to the pressure chambers are stacked one after another. The piezoelectric actuator is bonded to the cavity plate so as to close the pressure chambers in the cavity plate. Each of the piezoelectric sheets has a thickness of between 5-40 &mgr;m, preferably between 15-30 &mgr;m. Surface electrodes, which electrically connect one of the electrodes, are provided at both end portions of a surface of the piezoelectric actuator, which is opposed to a surface to be bonded to the cavity plate. Protrusions having a thickness of the surface electrodes are provided between the surface electrodes on the surface of the piezoelectric actuator.

Abstract: An actuator 120 is formed from nine piezoelectric sheets stacked in this order to give a laminated configuration. A common electrode 25 is formed on the upper surface of each piezoelectric sheet 122, 121b, 121d, 121f, 121g. A plurality of drive electrodes 24 are formed the upper surface of each piezoelectric sheet 121a, 121c, 121e, 123. The common electrodes 25, a cavity plate 14, and a cover plate 44 are all maintained at the same potential (0V). The lowermost piezoelectric sheet 122 formed with the common electrode 25 is located between the cavity plate 14 and the lowermost drive electrodes 24 on the piezoelectric sheet 121a. In this configuration, an ejection voltage applied to the drive electrodes 24 is reliably prevented from being applied to ink in a pressure chamber and/or the cavity plate 14, whereby reliable ink ejection is possible.

Abstract: Odd-numbered piezoelectric sheets 22, 21b, 21d, and 21f are formed with a plurality of individual electrodes 24. Even-numbered piezoelectric sheets 21a, 21c, 21e, and 21g are formed with a common electrode 25. These odd-numbered and even-numbered piezoelectric sheets are alternatively arranged one on the other to form a laminated body. A top sheet 23 is mounted on the laminated body. Surface electrodes 30, 31 are formed on the top sheet 23. Through holes 32, 33 are opened to the piezoelectric sheets 21a through 21g for providing electrical connection of the individual electrodes 24 and the common electrodes 25, but not to the piezoelectric sheet 22 that is laminated on a cavity plate 10.

Abstract: A print head for a piezoelectric ink jet printer includes a piezoelectric actuator in the form of a plate, which lies on one side of a metallic cavity plate. The actuator includes drive electrodes and side electrodes. The side electrodes are formed on a side face of the actuator and each connected with one of the drive electrodes. The cavity plate has pressure chambers each aligned with one of the drive electrodes. The cavity plate also has nozzles each communicating with one of the chambers. The cavity plate further has a recess formed on the one side. The side electrodes are aligned with the recess to be kept out of contact with the cavity plate. Another print head for a piezoelectric ink jet printer includes a piezoelectric actuator in the form of a plate, which lies on a cavity plate. The actuator has recesses formed in a side face of it, and includes drive electrodes and side electrodes. Each side electrode is formed in one of the recesses and connected with one of the drive electrodes.

Abstract: An actuator for the print head of an ink jet printer is fitted to the ink channels of the head. The actuator includes an active layer and a restraining layer. One side of the active layer faces the ink channels. The active layer can deform with a drive voltage applied to it. The restraining layer is provided on the other side of the active layer, and cannot be activated with a drive voltage. The restraining layer restrains the active layer from deforming. It is possible to integrally form the active and restraining layers by stacking green sheets and calcining the stacked sheets at the same time. This makes it possible to provide an actuator simple in structure and low-cost.

Abstract: An inkjet print head includes a piezoelectric actuator configured of stacked piezoelectric sheets with individual electrodes formed on the piezoelectric sheets. Positioning marks formed of the same material as the individual electrodes are formed one in each of the four corners of the piezoelectric sheets. A beam of light is radiated on the positioning marks in the stacked direction of the piezoelectric sheets, forming shadows of the positioning marks in each corner. The shadows are detected, and the center of gravity is determined for each shadow. Diagonal lines are drawn between the centers of gravity in opposing corners. The intersecting point of the diagonal lines serves as a reference point for bonding the piezoelectric actuator to the stacked cavity unit.

Abstract: A piezoelectric actuator is formed by laminating a piezoelectric sheet having individual electrodes and a piezoelectric sheet having a common electrode alternately. Through-holes are formed in the laminated piezoelectric sheets and coated with a conductive material to electrically connect the individual electrodes as well as the common electrodes in the laminating direction of the piezoelectric sheets. The maximum diameter (&phgr;) of each through-hole is not less than about 20 &mgr;m and not more than about 200 &mgr;m (20 &mgr;m≦&phgr;≦200 &mgr;m). In addition, the through-holes are provided in a staggered configuration in the laminating direction. In this arrangement, the piezoelectric actuator is less prone to warpage or waving and remains flat enough to offer high performance.

Abstract: An actuator 120 is formed from nine piezoelectric sheets stacked in this order to give a laminated configuration. A common electrode 25 is formed on the upper surface of each piezoelectric sheet 122, 121b, 121d, 121f, 121g. A plurality of drive electrodes 24 are formed the upper surface of each piezoelectric sheet 121a, 121c, 121e, 123. The common electrodes 25, a cavity plate 14, and a cover plate 44 are all maintained at the same potential (0V). The lowermost piezoelectric sheet 122 formed with the common electrode 25 is located between the cavity plate 14 and the lowermost drive electrodes 24 on the piezoelectric sheet 121a. In this configuration, an ejection voltage applied to the drive electrodes 24 is reliably prevented from being applied to ink in a pressure chamber and/or the cavity plate 14, whereby reliable ink ejection is possible.

Abstract: An ink jet print head includes a cavity plate having a plurality of nozzles and a plurality of pressure chambers communicating with the respective nozzles, and a plate-like piezoelectric actuator, in which piezoelectric sheets having a plurality of electrodes formed at positions with respect to the pressure chambers are stacked one after another. The piezoelectric actuator is bonded to the cavity plate so as to close the pressure chambers in the cavity plate. Each of the piezoelectric sheets has a thickness of between 5-40 &mgr;m, preferably between 15-30 &mgr;m. Surface electrodes, which electrically connect one of the electrodes, are provided at both end portions of a surface of the piezoelectric actuator, which is opposed to a surface to be bonded to the cavity plate. Protrusions having a thickness of the surface electrodes are provided between the surface electrodes on the surface of the piezoelectric actuator.

Abstract: Odd-numbered piezoelectric sheets 22, 21b, 21d, and 21f are formed with a plurality of individual electrodes 24. Even-numbered piezoelectric sheets 21a, 21c, 21e, and 21g are formed with a common electrode 25. These odd-numbered and even-numbered piezoelectric sheets are alternatively arranged one on the other to form a laminated body. A top sheet 23 is mounted on the laminated body. Surface electrodes 30, 31 are formed on the top sheet 23. Through holes 30, 31 are opened to the piezoelectric sheets 21a through 21g for providing electrical connection of the individual electrodes 24 and the common electrodes 25, but not to the piezoelectric sheet 22 that is laminated on a cavity plate 10.

Abstract: A print head for a piezoelectric ink jet printer includes a piezoelectric actuator in the form of a plate, which lies on one side of a metallic cavity plate. The actuator includes drive electrodes and side electrodes. The side electrodes are formed on a side face of the actuator and each connected with one of the drive electrodes. The cavity plate has pressure chambers each aligned with one of the drive electrodes. The cavity plate also has nozzles each communicating with one of the chambers. The cavity plate further has a recess formed on the one side. The side electrodes are aligned with the recess to be kept out of contact with the cavity plate. Another print head for a piezoelectric ink jet printer includes a piezoelectric actuator in the form of a plate, which lies on a cavity plate. The actuator has recesses formed in a side face of it, and includes drive electrodes and side electrodes. Each side electrode is formed in one of the recesses and connected with one of the drive electrodes.

Abstract: A method of manufacturing a nozzle plate and having a nozzle passage therethrough is provided as follows. First, a member having an ink ejection surface and an nozzle passage is formed. The member includes a straight conduit portion which is formed at one end portion of the nozzle passage located near the ink ejection surface and extending straight to an opening of the nozzle passage located on the ink ejection surface in order to eject an ink straight. A recess is formed on the ink ejection surface of the member such that an area of an opening of the recess is greater than an area of the opening of the nozzle passage and such that a depth of the recess is greater than a predetermined thickness. Subsequently, the ink ejection surface is ground by the predetermined thickness on the basis of a depth of the recess remaining on the ink ejection surface after grinding.

Abstract: A compressor includes a passage in the sidewall of the cylinder for directing compressed gas against circumferential surfaces of piston rings. The pressure of the gas from the passage counteracts the pressure of gas between the piston ring groove and the piston ring, and urges the piston rings inwardly. The force with which the piston ring is urged into engagement with the cylinder walls is lessened, thereby reducing wear of the piston rings. The arrangement is especially useful for compressors having piston rings formed of low friction polymeric materials, such as fluorine-containing polymers.

Abstract: An arrangement of two elements of a sewing machine which are in frictional, or sliding, contact during operation. At least one of elements is formed of a ceramic material and a minute amount of a lubrication oil is applied to the frictional, or siding, portion defining the surfaces in contact. Such a combination of elements is found in the upper looper mechanism, the shuttle body assembly, the needle bar mechanism and the fabric piece feeding mechanism in a sewing machine that are subject to high speed, high load friction or sliding conditions.