Abstract: There is provides liquid discharging apparatus including: head having nozzle; reservoir configured to store the liquid such that liquid surface is positioned higher than opening of the nozzle in a state that the reservoir stores the liquid of maximum storable amount; and atmosphere port connecting gas layer and outside of the reservoir. Inner diameter d of the nozzle and head difference h satisfy expression of ?hd /?cos??4/g, provided that p is specific weight of the liquid, ? is surface tension of the liquid, ? is contact angle of the liquid in the nozzle and g is gravitational acceleration, the head difference h being difference in height between meniscus in the opening of the nozzle and the liquid surface in the state that the reservoir stores the liquid of the maximum storable amount.

Abstract: A liquid droplet discharge apparatus includes a liquid droplet discharge head and a control unit. The liquid droplet discharge head includes: a plurality of main nozzles arranged in a first direction and discharging liquid droplets of main dots; and a plurality of sub nozzles arranged at end portion sides of arrays of the main nozzles and discharging liquid droplets of sub dots. The control unit is configured to control the liquid droplet discharge head to discharge the liquid droplets from the main and sub nozzles and to form sub dot arrays by the liquid droplets discharged from the sub nozzles in two arrays with being staggered at a predetermined interval in the second direction between main dot arrays by the liquid droplets discharged from the main nozzles, so as to form the dot arrays.

Abstract: A liquid droplet discharge apparatus includes a liquid droplet discharge head and a control unit. The liquid droplet discharge head includes: a plurality of main nozzles arranged in a first direction and discharging liquid droplets of main dots; and a plurality of sub nozzles arranged at end portion sides of arrays of the main nozzles and discharging liquid droplets of sub dots. The control unit is configured to control the liquid droplet discharge head to discharge the liquid droplets from the main and sub nozzles and to form sub dot arrays by the liquid droplets discharged from the sub nozzles in two arrays with being staggered at a predetermined interval in the second direction between main dot arrays by the liquid droplets discharged from the main nozzles, so as to form the dot arrays.

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-jet printer includes an ink jet head which jets liquid droplets of an ink onto a recording medium; a scanning mechanism which reciprocates the ink-jet head in a forward scan direction and a backward scan direction; a transport mechanism which transports the recording medium in a transport direction intersecting with the forward and backward scan directions; and a jetting controller which controls the ink-jet head. The jetting controller has a reference jetting amount setting section which sets a reference jetting amount based on an input image data for each of a plurality of scans of the ink-jet head, and a jetting amount adjusting section which makes a jetting amount be smaller than the reference jetting amount with respect to an overlapping area at which liquid droplet jetting areas of the forward scan and the backward scan partially overlap each other.

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: A liquid droplet jetting apparatus which jets liquid droplets includes: a liquid droplet jetting head which has a nozzle for jetting the liquid droplets; and a jetting controller which controls the liquid droplet jetting head to jet the liquid droplets from the nozzles by supplying the liquid droplet jetting head with a driving signal having a predetermined drive waveform in each of continuing driving periods, and which includes: a driving waveform selecting section which selects, with respect to each of the continuing driving periods, a driving waveform from a plurality of driving waveforms each having a wavelength which is same as a length of one driving period; and a driving waveform shifting section which shifts the driving waveform selected by the driving waveform selecting section.

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: 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-jet printer includes an ink jet head which jets liquid droplets of an ink onto a recording medium; a scanning mechanism which reciprocates the ink-jet head in a forward scan direction and a backward scan direction; a transport mechanism which transports the recording medium in a transport direction intersecting with the forward and backward scan directions; and a jetting controller which controls the ink-jet head. The jetting controller has a reference jetting amount setting section which sets a reference jetting amount based on an input image data for each of a plurality of scans of the ink-jet head, and a jetting amount adjusting section which makes a jetting amount be smaller than the reference jetting amount with respect to an overlapping area at which liquid droplet jetting areas of the forward scan and the backward scan partially overlap each other.

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 which jets liquid droplets includes: a liquid droplet jetting head which has a nozzle for jetting the liquid droplets; and a jetting controller which controls the liquid droplet jetting head to jet the liquid droplets from the nozzles by supplying the liquid droplet jetting head with a driving signal having a predetermined drive waveform in each of continuing driving periods, and which includes: a driving waveform selecting section which selects, with respect to each of the continuing driving periods, a driving waveform from a plurality of driving waveforms each having a wavelength which is same as a length of one driving period; and a driving waveform shifting section which shifts the driving waveform selected by the driving waveform selecting section.

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: 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 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: 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: 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 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: 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.