Abstract: A testing method includes sorting inkjet heads into a plurality of groups on the basis of known information about ink flow, preparing basic driving waveform data corresponding to each of the groups and modification data that partially modifies the basic driving waveform data to individually store them in advance in a storing section, creating individual waveform information that instructs combinations of the basic driving waveform data with the modification data with respect to an inkjet head to be tested to apply a modified driving waveform, and repeating the modification of the individual waveform information until a recording state becomes good.

Abstract: An ink droplet ejection device including: (a) actuators each operable to apply an ejection pressure to an ink stored in a corresponding pressure chamber, for causing an ink ejection through a corresponding nozzle, whereby an image formed as a result of the ink ejection is produced on a medium; and (b) a controller supplying a control signal to each actuator, and including (b-1) a portion operable to incorporate a composite-dot forming pulse train into the control signal, for causing successive ejection of a plurality of ink droplets that cooperate to form a composite dot of the image, and (c) a portion operable to incorporate a non-composite-dot forming pulse train into the control signal, for causing an ejection of a single ink droplet that forms a non-composite dot of the image.

Abstract: An ink droplet ejection device including: (a) actuators each operable to apply an ejection pressure to an ink stored in a corresponding pressure chamber, for causing an ink ejection through a corresponding nozzle, whereby an image formed as a result of the ink ejection is produced on a medium; and (b) a controller operable to supply a control signal to each actuator, and incorporating a drive pulse train into the control signal for causing ejection of at least two cooperative ink droplets that cooperate to form one dot of the image. The drive pulse train includes at least two drive pulses. One of the at least two drive pulses has a first pulse width smaller than a maximizing value that maximizes an ejection velocity and a volume of each ink droplet to be ejected. Another one of the at least two drive pulses has a second pulse width larger than the maximizing value. Also disclosed a method of producing the image on the medium by using the ink droplet ejection device.

Abstract: An ink-jet printing head comprising a flow-passage unit and an actuator unit laminated on each other, wherein the flow-passage unit has nozzles and pressure chambers communicating with the respective nozzles, and the actuator unit is operable to apply pressure to ink in each pressure chamber, and wherein each pressure chamber communicates at one of its opposite longitudinal ends with the corresponding nozzle, and at the other longitudinal end with an ink supply source, and is formed so as to be open in one of the opposite surfaces of the flow-passage unit, such that each pressure chamber is partially defined by the actuator unit, and wherein each pressure chamber has a depth of 35 ?m–45 ?m in a direction perpendicular to the opposite surfaces of the flow-passage unit.

Abstract: An ink ejecting device includes a plurality of nozzles, a plurality of pressure chambers respectively corresponding to the plurality of nozzles, an actuator capable of changing capacity of each of the plurality of pressure chambers. A first drive pulse signal is selected in accordance with dot information indicating dots to be formed on a recording medium successively. When the dot information for the current ejection cycle and the dot information for the succeeding ejection cycle indicate a first condition where ejection of a large amount of ink drop and no ejection of an ink drop, respectively, driving pulse signals for the current ejection cycle and the succeeding ejection cycle are selected, respectively. The driving pulse signals for the current ejection cycle and the succeeding ejection cycle are then output in the current ejection cycle and within the succeeding ejection cycle, respectively.

Abstract: A method of ejecting ink drops for a printing device having a plurality of nozzle arrays each including a plurality of nozzles arranged in line includes the steps of (1) delaying a timing at which the ejection pulse signals are applied for the nozzles of the nozzle arrays other than those of a reference nozzle array which is predetermined one of the plurality of nozzle arrays with respect to a timing at which the ejection pulse signals are applied for the nozzles of the reference nozzle array, and (2) delaying a timing at which the ejection pulse signals are applied for the nozzles which are to eject relatively small amount of ink drops with respect to a timing at which the ejection pulse signals are applied for the nozzles which are to eject relatively large amount of ink drops for each nozzle array.

Abstract: A novel process for producing a dry preform for a composite material takes advantage of the fact that a reinforcing filament assembly, when consisting of a fiber reinforcement layer a, formed by stringing a first set of parallel strands of fiber reinforcement over a part or all of the plane within any desired shape along the straight axis 2, and a fiber reinforcement layer b, formed by stringing a second set of parallel strands of fiber reinforcement over the plane at an angle &thgr; with respect to the straight axis 2, such that 0°<&thgr;<180°, the part of the reinforcing filament assembly that consists solely of the fiber reinforcement b can be deformed as desired. According to this process, strands c of fiber reinforcement are strung using a fiber reinforcement string jig as shown in FIGS. 8(A) and 8(B). The layers of the strung strands of fiber reinforcement are brought together by a simple means such as stitching.

Abstract: An ink-jet printing head comprising a flow-passage unit and an actuator unit laminated on each other, wherein the flow-passage unit has nozzles and pressure chambers communicating with the respective nozzles, and the actuator unit is operable to apply pressure to ink in each pressure chamber, and wherein each pressure chamber communicates at one of its opposite longitudinal ends with the corresponding nozzle, and at the other longitudinal end with an ink supply source, and is formed so as to be open in one of the opposite surfaces of the flow-passage unit, such that each pressure chamber is partially defined by the actuator unit, and wherein each pressure chamber has a depth of 35 &mgr;m-45 &mgr;m in a direction perpendicular to the opposite surfaces of the flow-passage unit.

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 head controller generates drive waveforms selectively at predetermined print cycles to cause ink ejection from a cavity. A waveform generator generates a plurality of waveform signals, including a waveform signal extending over two adjacent print cycles, and a waveform selector selects and outputs to the ink-jet head one of a plurality of waveform signals, based on whether dot data for two adjacent print cycles indicates ink ejection. The waveform selector selects a waveform signal extending over two adjacent print cycles when dot data for a current print cycle indicates ink ejection while dot data for a next print cycle indicates no ink ejection. In addition, a plurality of drive pulses cause ejection of a plurality of ink droplets to form a dot outputted after a certain delay from the start of the current print cycle.

Abstract: A drive device used for an ink droplet ejecting apparatus prevents an occurrence of a satellite ink droplet and improves printing quality. When ejection of an ink droplet is performed with two pulses and an ambient temperature surrounding a head is between low and medium, a pulse output period between first and second ejection pulses is set to be 5AL (AL=a cycle of a pressure wave in a pressure chamber/2). When ejection of an ink droplet is performed with three pulses and the ambient temperature surrounding the head is between low and medium, the pulse output period between first and second ejection pulses and between second and third pulses is both set to be 5AL.

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: A drive device used for an ink droplet ejecting apparatus prevents an occurrence of a satellite ink droplet and improves printing quality. When ejection of an ink droplet is performed with two pulses and an ambient temperature surrounding a head is between low and medium, a pulse output period between first and second ejection pulses is set to be 5AL (AL=a cycle of a pressure wave in a pressure chamber/2). When ejection of an ink droplet is performed with three pulses and the ambient temperature surrounding the head is between low and medium, the pulse output period between first and second ejection pulses and between second and third pulses is both set to be 5AL.

Abstract: An ink-jet head controller generates drive waveforms selectively at predetermined print cycles to cause ink ejection from a cavity. A waveform generator generates a plurality of waveform signals, including a waveform signal extending over two adjacent print cycles, and a waveform selector selects and outputs to the ink-jet head one of a plurality of waveform signals, based on whether dot data for two adjacent print cycles indicates ink ejection. The waveform selector selects a waveform signal extending over two adjacent print cycles when dot data for a current print cycle indicates ink ejection while dot data for a next print cycle indicates no ink ejection. In addition, a plurality of drive pulses cause ejection of a plurality of ink droplets to form a dot outputted after a certain delay from the start of the current print cycle.

Abstract: A driving device for a piezoelectric element is provided which attains lower power consumption, low heat generation and low cost. To displace a piezoelectric element, a first switching transistor is rendered ON by a control circuit. The electric charges flow in the piezoelectric element from the power supply through the first switching transistor. This state is continued until a sufficient amount of electric charges are stored in the piezoelectric element. To restore the piezoelectric element thus displaced, a second switching transistor is rendered ON under the condition where the first switching transistor is OFF. In this condition, a resonance circuit is formed by the piezoelectric element and the coil. When the electric charges are flowing in the coil and a predetermined period of time has elapsed after the second switching transistor is rendered ON, the control circuit renders the second switching transistor OFF, whereby the current flowing in the coil flows into the power supply.

Abstract: A printer for recording information on one of opposite surfaces of a recording medium, including a recording head displaceable along the one surface of the recording medium, for recording the information on the one surface, a platen device for defining a platen surface which is opposed to the recording head, a vibration device for applying vibration to the platen means and thereby vibrating the platen surface, and an actuating device for, when the recording head is displaced along the one surface of the recording medium, displacing the platen device along the other of the opposite surfaces of the recording medium in a same direction as a direction of the displacement of the recording head and in synchronism with the displacement of the recording head, so that the platen surface continues to be opposed to the recording head.

Abstract: Piezoelectric elements that can resonate at a certain frequency with a coil are extended and contracted as they are repeatedly charged and discharged. The extending and contracting movements of the piezoelectric elements are amplified and transmitted to move the print wires toward and away from the platen. The waveform of a voltage generated across the piezoelectric element is detected by a monitoring device. Then, the detected voltage waveform is compared with the waveform of a voltage that is produced when the print gap is proper, and lets the user to know the magnitude of the print gap between the distal ends of print wires and a platen at any time during printing operation.

Abstract: A dot printing apparatus in which the piezoelectric print head having the piezoelectric element connected to the printing wire is utilized and the secondary bounce of the printing wire is effectively controlled according to one of three dot printing modes (the normal continuous dot printing mode, the last dot printing mode in the continuous dot printing mode and the single dot printing mode), is disclosed. The dot is judged every time the dot printing is performed. And if judged the normal dot printing mode, the discharging of the piezoelectric element is conducted relatively fast after the dot printing in the present printing pitch is performed to charge the piezoelectric element, since the dot printing data exists in one or more printing pitches both before and after the present printing pitch, thus, the dot printing in printing pitch next to the present printing pitch is performed.

Abstract: A driver circuit for driving a piezoelectric element, including a charging circuit having a DC power source and a coil for charging the piezoelectric element, and a discharging circuit for discharging the piezoelectric element. When the piezoelectric element is charged, a first switching device in the charging circuit is held on until a voltage of the element reaches a predetermined level below a line voltage of the power source. A second switching device provided in the discharging circuit is turned on at the time when the first switching device is turned off or at a predetermined later time, and is turned off by the time when said first switching device is again turned on next activation of the piezoelectric element. A voltage limiter inhibits the voltage of the piezoelectric element element from exceeding the predetermined level.

Abstract: A device for magnifying displacement of a piezoelectric element adapted to be displaced by application of voltage thereto, comprising a frame extending substantially parallel to a direction of displacement of the piezoelectric element; a movable member fixed to a first end of the piezoelectric element with respect to the direction of displacement; a first mount surface formed on said frame and extending substantially parallel to the direction of displacement; a second mount surface formed on the movable member and extending substantially parallel to the direction of displacement, which second mount surface is opposed to the first mount surface; a first leaf spring mounted at a first end portion on the first mount surface and extending substantially parallel to the direction of displacement; a second leaf spring mounted at a first end portion on the second mount surface and extending substantially parallel to the direction of displacement; and a rolling member fixed to second end portions of the first and seco