Abstract: An ink jet printer is provided with an ink jet head and a controller. The ink jet head comprises a nozzle, an ink chamber communicating with the nozzle, a pressure chamber located between the nozzle and the ink chamber, and an actuator that changes volume of the pressure chamber. The controller controls the actuator to perform a first performance. The first performance includes a first change in which the volume of the pressure chamber increases and a second change in which the volume of the pressure chamber decreases. A period from the first change to the second change is 2/3×AL or below, or within a range between (2s?1/2)×AL and (2s+2/3)×AL, s is a positive integer. Discharging speed of ink discharged from the nozzle is substantially maximum if the period from the first change to the second change is set to AL.

Abstract: A test sheet is set in a droplet discharge device at a first distance. At least one droplet is discharged toward the test sheet from a nozzle formed in the droplet discharge device to form at least one first dot on the test sheet. The test sheet is set in the droplet discharge device at a second distance differing from the first distance. At least one droplet is discharged toward the test sheet from the nozzle to form at least one second dot on the test sheet. A nozzle position error or a nozzle discharge angle error are calculated from the position of the first dot, the position of the second dot, the first distance, and the second distance. Testing inkjet heads in this manner allows accurate testing for errors in nozzle position or discharge angle.

Abstract: A controller of an ink jet head includes a waveform information storage section for storing waveform patterns concerning a plurality of types of drive signals capable of making positions of dots formed on print paper by ejecting ink from nozzles different from each other with respect to a predetermined direction orthogonal to a relative moving direction between the print paper and the ink jet head. The controller further includes a waveform selection section for selecting one drive signal from among the plurality of drive signals stored in the waveform information storage section so that the same type of drive signal is not selected n or more successive times (where n is a natural number of two or more) for each nozzle.

Abstract: A liquid ejection head includes a passage unit and an actuator. A nozzle for ejecting liquid and a common liquid chamber are formed in the passage unit. An individual liquid passage formed in the passage unit includes a first passage a pressure chamber, a second passage, and a restricted passage. The first passage communicates between the nozzle and the pressure chamber. The second passage communicates between the pressure chamber and the restricted passage. The restricted passage is smaller than the second passage in the sectional area perpendicular to the flow of the liquid. The actuator can selectively take a first state in which the volume of the pressure chamber is V1 and a second state in which the volume of the pressure chamber is V2 larger than V1. The actuator changes from the first state into the second state and then returns to the first state to eject the liquid from the nozzle.

Abstract: An ink jet printer is provided with a passage unit, an actuator, and a pulse applying device. The passage unit comprises a nozzle, a pressure chamber, and an ink passage located between the nozzle and the pressure chamber. The actuator faces the pressure chamber and comprises a first electrode, a second electrode to which a reference potential can be applied, and a piezoelectric element located between the first electrode and the second electrode. The pulse applying device is capable of applying a first voltage pulse to the first electrode such that the nozzle discharges an ink droplet, and a second voltage pulse to the first electrode such that the nozzle does not discharge the ink droplet. A voltage change on a leading edge and/or a trailing edge of the second voltage pulse is greater than a voltage change on a leading edge and/or a trailing edge of the first voltage pulse.

Abstract: There is provided an inkjet head printing device, which includes an inkjet head having an ink flow channel unit and a piezoelectric actuator unit, and a pulse generator that determines first pulse patterns to be applied to electrodes respectively corresponding to nozzles determined to eject the ink, each of the first pulse patterns having a first potential which causes each of the plurality of nozzles to eject the ink. The pulse generator further determines a second pulse pattern to be applied to at least one of electrodes respectively corresponding to nozzles determined not to eject the ink, the second pulse pattern having a second potential which does not cause each of the plurality of nozzles to eject the ink.

Abstract: An actuator can selectively switch a volume of a pressure chamber between a first state V1 and a second state V2, which is greater than V1. The actuator changes from the first state into the second state and then changes back into the first state to eject ink from an ejection port. A controller controls the actuator such that To/Tc falls within a range from 0.51 to 0.54. To represents the time period between time the actuator starts to change from the first state into the second state, to a time the actuator starts to change from the second state into the first state. Tc represents the period of proper oscillation of ink filling up the individual ink passage. The actuator is controlled so that a variation in ink ejection speed is prevented from being too large relative to the variation in the degree of deformation of the actuator.

Abstract: An aspect of the invention provides an inkjet printer including: an inkjet head and a controller. The inkjet head moves relative to a recording medium to perform printing. The inkjet head includes, a flow path unit including plural pressure chambers respectively communicating with plural ink ejection ports that ejects ink droplets toward the recording medium, and a piezoelectric actuator configured to take a first state and a second state. The controller supplies a drive pulse signal to the piezoelectric actuator in order to repeat an operation in which the piezoelectric actuator transits from the first state to the second state and returns to the first state, for enabling the corresponding ink ejection port to eject a plurality of ink droplets. The controller supplies the drive pulse signal so that timings of the transition and the return satisfy some relationships.

Abstract: An inkjet head in which cross-talk between adjacent pressure chambers is suppressed. The inkjet head has a channel unit having pressure chambers and nozzles communication with the pressure chambers, and an actuator unit fixed to one surface of the channel unit for changing the volume of the pressure chamber. The actuator unit includes individual electrodes provided opposed to the plurality of pressure chambers for receiving a drive signal to change the volume of the pressure chamber; a common electrode provided over the plurality of pressure chambers; a piezoelectric sheet provided between the individual electrode and the common electrode; and an independent electrode provided between adjacent individual electrodes and electrically isolated from the common electrode and the individual electrodes. An inductor is electrically connected between the independent electrode and a portion whose electric potential is substantially the same as that of the common electrode.

Abstract: An ink jet printer is provided with an ink jet head and a controller. The ink jet head comprises a nozzle, an ink chamber communicating with the nozzle, a pressure chamber located between the nozzle and the ink chamber, and an actuator that changes volume of the pressure chamber. The controller controls the actuator to perform a first performance. The first performance includes a first change in which the volume of the pressure chamber increases and a second change in which the volume of the pressure chamber decreases. A period from the first change to the second change is 2/3×AL or below, or within a range between (2s?1/2)×AL and (2s+2/3)×AL. s is a positive integer. Discharging speed of ink discharged from the nozzle is substantially maximum if the period from the first change to the second change is set to AL.

Abstract: A test sheet is set in a droplet discharge device at a first distance. At least one droplet is discharged toward the test sheet from a nozzle formed in the droplet discharge device to form at least one first dot on the test sheet. The test sheet is set in the droplet discharge device at a second distance differing from the first distance. At least one droplet is discharged toward the test sheet from the nozzle to form at least one second dot on the test sheet. A nozzle position error or a nozzle discharge angle error are calculated from the position of the first dot, the position of the second dot, the first distance, and the second distance. Testing inkjet heads in this manner allows accurate testing for errors in nozzle position or discharge angle.

Abstract: In order to preserve good droplet discharge efficiency in a droplet discharge device, a plurality of timings are set within a period in which a plurality of droplets are to be discharged to a target position. Consecutive timings are divided by a cycle time of pressure wave that is generated inside a pressure chamber by transmitting a signal to an actuator. When a plurality of signals are applied to the actuator at consecutive timings, the peak of the pressure wave and the application of the signals are synchronous, and the droplet discharge efficiency will be improved. However, the consecutive number of timings at which the consecutive signals are transmitted is limited to a predetermined number. In this way, the pressure inside the pressure chamber can be prevented from becoming too high.

Abstract: An actuator unit is driven with a voltage pulse supplied from a driver IC. The actuator unit can take two states of a first state wherein the volume of a pressure chamber is V1, and a second state wherein the volume of the pressure chamber is V2 larger than V1. A state of the actuator unit changes from the first state to the second state and then to the first state again so that ink is ejected through a nozzle connected to one end of the pressure chamber. A pulse width Tw of the voltage pulse to be supplied to the actuator unit is shorter than a pulse width Tmax at which a maximum ejection speed of ink ejected from the nozzle is obtained. Thus, with simplifying a waveform of the voltage pulse, two of large and small ink droplets can be successively ejected in the order of the large and small ink droplets.

Abstract: The invention relates to a method for setting a tolerance of each standard value, which is a factor in determination of ink droplets landing accuracy, to an ink jet printer that is set up using the method, by implementing a sensory test using printed results of an ink jet printer. With the tolerances set by the method, banding can be effectively obscured without significantly improving the mechanical precision of the ink jet printer. Particularly, when A1 is a deviation of a sheet feeding amount in the sub-scanning direction obtained by a dot line length of an average value of the sheet feeding amount in the sub-scanning direction from an ideal value, B1 is a maximum value of a deviation in the sub-scanning direction between the same color dots, and C1 is a maximum value of a deviation in the main scanning direction between the same color dots, it is set such that a value of tolerances of A1, B1, and C1 is A1?B1?C1.

Abstract: An ink jet printer is provided with an ink jet head, an applying device, a first storage, an inputting device, and a second storage. The ink jet head comprises a nozzle that discharges an ink droplet toward a print medium, and an actuator that makes the nozzle discharge the ink droplet when a pulse signal is applied to the actuator. The applying device is capable of applying at least two kinds of pulse signals to the actuator. The pulse width of each kind of pulse signal mutually differs. The first storage stores at least two kinds of base pulse widths. Each kind of base pulse width corresponds with a different kind of pulse signal. Each kind of base pulse width mutually differs. The inputting device inputs a predetermined value. The second storage stores the predetermined value input by the inputting device.

Abstract: A printer is provided with an ink jet head and a controller. The ink jet head prints on a print medium by discharging ink. The ink jet head comprises a plurality of units. Each unit comprises a nozzle for discharging ink, a pressure chamber communicating with the nozzle, and a piezoelectric element facing the pressure chamber. The piezoelectric elements form at least two element lines. Each element line is formed by at least two piezoelectric elements aligned in a first direction. Each element line is aligned in a sec direction which is different from the first direction. The controller controls the ink jet head to print on the print medium by changing voltage applied to each piezoelectric element of the ink jet head. The controller controls timings at which the controller changes voltage applied to each piezoelectric element by the element line.

Abstract: A controller of an ink jet head includes a waveform information storage section for storing waveform patterns concerning a plurality of types of drive signals capable of making positions of dots formed on print paper by ejecting ink from nozzles different from each other with respect to a predetermined direction orthogonal to a relative moving direction between the print paper and the ink jet head. The controller further includes a waveform selection section for selecting one drive signal from among the plurality of drive signals stored in the waveform information storage section so that the same type of drive signal is not selected n or more successive times (where n is a natural number of two or more) for each nozzle.

Abstract: An inkjet head in which cross-talk between adjacent pressure chambers is suppressed. The inkjet head has a channel unit having pressure chambers and nozzles communication with the pressure chambers, and an actuator unit fixed to one surface of the channel unit for changing the volume of the pressure chamber. The actuator unit includes individual electrodes provided opposed to the plurality of pressure chambers for receiving a drive signal to change the volume of the pressure chamber; a common electrode provided over the plurality of pressure chambers; a piezoelectric sheet provided between the individual electrode and the common electrode; and an independent electrode provided between adjacent individual electrodes and electrically isolated from the common electrode and the individual electrodes. An inductor is electrically connected between the independent electrode and a portion whose electric potential is substantially the same as that of the common electrode.

Abstract: There is provided an inkjet head printing device, which includes an inkjet head that has an ink flow channel unit including a plurality of nozzles for ejecting ink and a plurality of pressure chambers respectively provided for the plurality of nozzles and has a piezoelectric actuator unit including a plurality of electrodes. The inkjet head further includes a pulse controller that generates a plurality of types of ejection pulse patterns having different phases and drives the plurality of electrodes corresponding to the plurality of nozzles which are to eject the ink using the plurality of types of ejection pulse patterns.

Abstract: There is provided an inkjet head printing device, which includes an inkjet head having an ink flow channel unit and a piezoelectric actuator unit, and a pulse generator that determines first pulse patterns to be applied to electrodes respectively corresponding to nozzles determined to eject the ink, each of the first pulse patterns having a first potential which causes each of the plurality of nozzles to eject the ink. The pulse generator further determines a second pulse pattern to be applied to at least one of electrodes respectively corresponding to nozzles determined not to eject the ink, the second pulse pattern having a second potential which does not cause each of the plurality of nozzles to eject the ink.