Abstract: For forming one dot by jetting a plurality of ink droplets, a drive pulse signal in an ink-droplet jetting apparatus includes a first main pulse for jetting, a first regulating signal which is inserted at a first interval from the first main pulse, and a second regulating pulse which is inserted at a second interval from the first main pulse. The first interval is almost the same as or more than the second interval. Accordingly, the ink-droplet jetting apparatus is capable of jetting the ink droplets stably, and printing at a high speed.

Abstract: A droplet ejecting head is formed with at least one nozzle and is configured to eject a liquid droplet through the at least one nozzle in a nozzle axis direction. A carriage supports the droplet ejecting head. A guide member extends in a predetermined direction and is configured to guide the carriage so that the carriage is movable in the predetermined direction. A moving section moves the carriage along the guide member. The droplet ejecting head is configured to eject a liquid droplet through the at least one nozzle onto an ejection object while the moving section moves the carriage. A vibration generating section vibrates the droplet ejecting head in such a manner that vibration of liquid held in the at least one nozzle includes a component in the nozzle axis direction.

Abstract: Combinations of delay times in jetting timings, for a predetermined number of nozzle groups selected from a plurality of nozzle groups, are set; and jetting speeds at each of the delay-time combinations are measured. Next, a variation in jetting speeds when the ink is jetted from the plurality of nozzle groups is estimated from the jetting speeds measured for each of the predetermined number of nozzle groups. Further, a combination of the delay times in the jetting timings is determined such that the estimated variation in the jetting speeds is smaller than a predetermined threshold value. Accordingly, it is possible to determine a combination of delay times in the jetting timings such that a variation in discharge characteristics when the ink is jetted concurrently from the plurality of nozzles is small, thereby improving the reproducibility of image.

Abstract: A liquid ejector including: a nozzle; a pressure chamber communicating, at one end thereof in a specific direction, with the nozzle; a liquid-store chamber; a restrictor through which the other end of the pressure chamber in the specific direction and the liquid-store chamber communicate with each other; and an actuator having a plurality of piezoelectric layers, a pair of electrode layers, and an active portion that is constituted by a portion of one of the plurality of piezoelectric layers, which portion is interposed between the pair of electrode layers, wherein the active portion is disposed at a position corresponding to the pressure chamber so as to extend in the specific direction, and has a shorter length than the pressure chamber in the specific direction, and wherein a center of the active portion in the specific direction is shifted toward the nozzle than a center of the pressure chamber in the specific direction.

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: 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: A liquid ejection apparatus includes: a liquid ejection head having a nozzle, wherein the liquid ejection head can eject a liquid from the nozzle and is movable in a predetermined direction; a first controller that controls, based on input data, liquid ejection of the liquid ejection head from the nozzle and movement of the liquid ejection head in the predetermined direction to apply the liquid onto an ejection area of a medium; a second controller that controls a flushing operation by moving the liquid ejection head to a flushing area outside the ejection area in the predetermined direction and ejecting the liquid from the nozzle of the liquid ejection head to the flushing area; a third controller that controls a minute vibration operation by vibrating the liquid in the nozzle to such an extent as not to eject the liquid from the nozzle; and a fourth controller that obtains information regarding the ejection area in the predetermined direction and that selectively controls the second controller and the third

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 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: 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 ? with respect to the straight axis 2, such that 0°<?<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: 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: Combinations of delay times in jetting timings, for a predetermined number of nozzle groups selected from a plurality of nozzle groups, are set; and jetting speeds at each of the delay-time combinations are measured. Next, a variation in jetting speeds when the ink is jetted from the plurality of nozzle groups is estimated from the jetting speeds measured for each of the predetermined number of nozzle groups. Further, a combination of the delay times in the jetting timings is determined such that the estimated variation in the jetting speeds is smaller than a predetermined threshold value. Accordingly, it is possible to determine a combination of delay times in the jetting timings such that a variation in discharge characteristics when the ink is jetted concurrently from the plurality of nozzles is small, thereby improving the reproducibility of image.

Abstract: For forming one dot by jetting a plurality of ink droplets, a drive pulse signal in an ink-droplet jetting apparatus includes a first main pulse for jetting, a first regulating signal which is inserted at a first interval from the first main pulse, and a second regulating pulse which is inserted at a second interval from the first main pulse. The first interval is almost the same as or more than the second interval. Accordingly, the ink-droplet jetting apparatus is capable of jetting the ink droplets stably, and printing at a high speed.

Abstract: A driving pulse signal for forming one dot includes a first, a second, and a third main pulses applied intermittently with an intervals to eject an ink droplet, and a stabilizing pulse which is inserted between the main pulses, and which suppresses a residual vibration of an ink in a pressure chamber, generated by a main pulse applied previously. The third main pulse suppresses the residual vibration of the ink generated by the second main pulse, and also a pulse width of the third pulse is adjusted such that there is no residual vibration remained, due to application of the last main pulse. Consequently, it is possible to suppress effectively the residual vibration of the ink by the less number of the stabilizing pulses compared to the number of main pulses. As a result, an overall pulse width becomes short, and it is possible to increase the recording speed.

Abstract: A liquid-droplet jetting apparatus is provided with a cavity unit in which nozzles and pressure chambers are formed; and a piezoelectric actuator which includes active portions which deforms when a drive voltage is applied thereto. In the apparatus, the active portions are deformed to change the volume of the pressure chambers to thereby jet a liquid in the pressure chambers from the nozzles. The active portions are grouped into a plurality of groups which are different in the length in the longitudinal direction of the active portions. Active portions with a greater length have a greater width, and active portions with a smaller length have a smaller width. Accordingly, in the liquid-droplet jetting apparatus in which the active portions are grouped into the jetting groups, drive voltages can be made substantially same with respect to all the jetting groups.

Abstract: In a liquid-droplet jetting apparatus such as an ink-jet head having a plurality of nozzle rows formed therein, an ink is jetted from one of the nozzle rows and the ink is jetted from another nozzle row concurrently while changing delay times by each of which a jetting timing for the nozzle row is delayed with respect to a jetting timing for the another nozzle row. Then, an optimum image is determined among images formed by the ink jetted from these two nozzle rows, and a delay time in the jetting timings is extracted, among the delay times, which correspond to the optimum image. By determining the delay time in the nozzle rows in such a manner, the variation in jetting characteristics is small in the nozzle rows, thereby realizing satisfactory reproducibility of image.

Abstract: In a liquid-droplet jetting apparatus constructed to change volume of pressure chambers in a cavity unit by displacement of active portions in a piezoelectric actuator so as to jet liquid in the pressure chambers from nozzles, respectively, the pressure chambers and the active portions extend on a predetermined plane; a length in a longitudinal direction of each of the active portions is not more than 1.5 mm, a height of each of the pressure chambers is 40 ?m to 60 ?m, and a thickness of a member which defines surfaces, of the pressure chambers, on a side opposing the piezoelectric actuator is 100 ?m to 150 ?m. The liquid-droplet jetting apparatus can stably jet a liquid-droplet having a minute volume at a predetermined speed without increasing a drive voltage applied to the active portions.

Abstract: An ink-jet head includes pressure chambers arranged in a row in a row-direction, and a manifold flow passage communicated with the pressure chambers and extending in the row-direction. An ink inflow port is formed at one end of the manifold flow passage. The manifold flow passage has a main portion, a connecting portion, and an extended portion which are arranged in this order from a side close to the ink inflow port. The manifold flow passage is communicated with the pressure chambers at the main portion. The main portion has a constant cross-sectional area greater than that of the connecting portion. A cross-sectional area of the extended portion is greater than that of the connecting portion. The pressure wave, generated in the pressure chamber and propagated to the manifold flow passage, can be efficiently attenuated by the manifold flow passage constructed as described above.

Abstract: There is disclosed an ink-droplet ejecting apparatus including: ink passages each including a pressure chamber filled with ink; actuators each operated to change, upon receiving a drive signal, an inner volume of one of the chambers to generate a pressure wave in the ink in the chamber which propagates along the passage to eject a droplet of the ink onto a recording medium; and a control unit connected to the actuators and supplying the signal to the actuators such that the signal is in one of at least one waveform including a waveform which is for forming a single dot on the medium and includes a main pulse for ejecting the droplet, a preceding pulse outputted before the main pulse, and a stabilizing pulse outputted after the main pulse. A pulse width of the main pulse is not coincident with a one-way propagation time AL which is a time taken by the pressure wave to propagate one way along the passage. The preceding pulse is outputted in a manner not to eject the droplet.