Abstract: In accordance with an embodiment, a drive method for an ink jet head comprising: a drive pulse, applying a first pulse for increasing and then restoring the volume of a pressure chamber and giving pressure vibration to the chamber in which ink are accommodated, and then a second pulse for reducing and then restoring the volume of the pressure chamber to an actuator arranged corresponding to the pressure chamber; wherein the second pulse is turned on at first point of time causing the pressure vibration amplitude at second point of time to be the same with that of generated by the first pulse when the first pulse is turned on, wherein the second point of time is the time when flow velocity of the ink nearby the nozzle inside the pressure chamber becomes 0 after the first point of time, and the second pulse is turned off at the second point of time.

Abstract: In accordance with an embodiment, a drive method for an ink jet head comprising: a drive pulse, applying a first pulse for increasing and then restoring the volume of a pressure chamber and giving pressure vibration to the chamber in which ink are accommodated, and then a second pulse for reducing and then restoring the volume of the pressure chamber to an actuator arranged corresponding to the pressure chamber; wherein the second pulse is turned on at first point of time causing the pressure vibration amplitude at second point of time to be the same with that of generated by the first pulse when the first pulse is turned on, wherein the second point of time is the time when flow velocity of the ink nearby the nozzle inside the pressure chamber becomes 0 after the first point of time, and the second pulse is turned off at the second point of time.

Abstract: A driving device of an inkjet head including a pressure chamber for accommodating ink, a nozzle that communicates with the pressure chamber to eject the ink in the pressure chamber, and an actuator for expanding or contracting a volume of the pressure chamber, is provided with a drive circuit that applies a driving signal to the inkjet head. The driving signal includes: a first contracting pulse, a first expanding pulse following the first contracting pulse, a second contracting pulse following the first expanding pulse, a second expanding pulse following the second contracting pulse, and a third contracting pulse following the second expanding pulse.

Abstract: An ink jet head includes a plurality of nozzles and a piezoelectric member provided with driving channels for storing ink. Each of the driving channels communicates a respective one of the nozzles. Dummy channels are alternately arranged with the driving channels. First side walls between the driving and dummy channels include a first driving channel side surface and a first dummy side surface. Second side walls between the driving channels and the dummy channels include a second driving channel side surface and a second dummy channel side surface. When a voltage is applied to electrodes on the first dummy channel side surfaces, the corresponding first side wall is deformed. When a voltage is applied to electrodes on the second dummy channel side surfaces, the second side wall is deformed.

Abstract: A driving device of an Inkjet head including a pressure chamber for accommodating ink, a nozzle that communicates with the pressure chamber to eject the ink in the pressure chamber, and an actuator for expanding or contracting a volume of the pressure chamber, is provided with a drive circuit that applies a driving signal to the Inkjet head. The driving signal includes: a first contracting pulse, a first expanding pulse following the first contracting pulse, a second contracting pulse following the first expanding pulse, a second expanding pulse following the second contracting pulse, and a third contracting pulse following the second expanding pulse.

Abstract: An ink jet head includes a plurality of nozzles and a piezoelectric member provided with driving channels for storing ink. Each of the driving channels communicates a respective one of the nozzles. Dummy channels are alternately arranged with the driving channels. First side walls between the driving and dummy channels include a first driving channel side surface and a first dummy side surface. Second side walls between the driving channels and the dummy channels include a second driving channel side surface and a second dummy channel side surface. When a voltage is applied to electrodes on the first dummy channel side surfaces, the corresponding first side wall is deformed. When a voltage is applied to electrodes on the second dummy channel side surfaces, the second side wall is deformed.

Abstract: According to one embodiment, a driving method of an ink jet head includes applying a first pulse for expanding volume of a pressure chamber in which an ink is accommodated to an actuator for applying oscillation to the pressure chamber and applying a second pulse for reducing volume of the pressure chamber to the actuator immediately before ink drops discharged from a nozzle which is communicated with the pressure chamber are separated from the nozzle.

Abstract: According to one embodiment, a driving method of an ink jet head includes applying a first pulse for expanding volume of a pressure chamber in which an ink is accommodated to an actuator for applying oscillation to the pressure chamber and applying a second pulse for reducing volume of the pressure chamber to the actuator immediately before ink drops discharged from a nozzle which is communicated with the pressure chamber are separated from the nozzle.

Abstract: An inkjet recording apparatus includes actuators provided in an inkjet head, and a drive voltage generator that drives each actuator. The drive voltage generator is configured to set the cycle time Tc, the drop cycle Td, the number of ink droplets N for a maximum tone, and the inactive period Te in a relationship of Tc=Td×N+Te, set the drop cycle Td and the inactive period Te, by referencing pressure propagation time Ta in relationships of Td=n×Ta (where n=1, 2, 3, . . . ) and Te=(0.5+m)×Ta (where m=1, 2, 3, . . . ), and make an output timing of the final drive pulse signal for a dot of a tone other than the maximum tone coincide with an output timing of the final drive pulse signal for the maximum tone.

Abstract: In an ink jet head driving method for applying a drive pulse to an actuator ACT to change capacities of a plurality of pressure chambers in which ink has been filled, ejecting an ink droplet from a nozzle formed in communication with the pressure chamber to print onto a printing medium, and moreover, controlling the number of ink droplets ejected according to the number of drive pulses to carry out gradation printing, a control is made such that, in the case where the number of ink droplets is small, a boost pulse Pb for amplifying a pressure vibration of the pressure chamber is applied prior to a drive pulse for ejecting a first ink droplet, and in the case where the number of ink droplets is large, applying of the boost pulse Pb is disabled.

Abstract: There is provided an ink jet head driving method for applying a drive pulse to an actuator to change capacities of a plurality of pressure chambers in which ink has been filled, ejecting an ink droplet from a nozzle formed in communication with the pressure chamber to print onto a printing medium, and moreover, continuously ejecting a plurality of liquid droplets to carry out gradation printing according to the number of liquid droplets, the method including making control so as to, in the case where the number of the liquid droplets is smaller than a predetermined number, apply a boost pulse to amplify a pressure vibration of the pressure chamber prior to a drive pulse for ejecting a first liquid droplet, and in the case where the number of liquid droplets is equal to or greater than the predetermined number, disable applying of the boost pulse.

Abstract: An inkjet recording apparatus includes actuators provided in an inkjet head, and a drive voltage generator that drives each actuator. The drive voltage generator is configured to set the cycle time Tc, the drop cycle Td, the number of ink droplets N for a maximum tone, and the inactive period Te in a relationship of Tc=Td×N+Te, set the drop cycle Td and the inactive period Te, by referencing pressure propagation time Ta in relationships of Td=n×Ta (where n=1, 2, 3, . . . ) and Te=(0.5+m)×Ta (where m=1, 2, 3, . . . ), and make an output timing of the final drive pulse signal for a dot of a tone other than the maximum tone coincide with an output timing of the final drive pulse signal for the maximum tone.

Abstract: In an ink jet head driving method for applying a drive pulse to an actuator ACT to change capacities of a plurality of pressure chambers in which ink has been filled, ejecting an ink droplet from a nozzle formed in communication with the pressure chamber to print onto a printing medium, and moreover, controlling the number of ink droplets ejected according to the number of drive pulses to carry out gradation printing, a control is made such that, in the case where the number of ink droplets is small, a boost pulse Pb for amplifying a pressure vibration of the pressure chamber is applied prior to a drive pulse for ejecting a first ink droplet, and in the case where the number of ink droplets is large, applying of the boost pulse Pb is disabled.

Abstract: An ink-jet recording apparatus includes a pressure chamber that contains ink, a nozzle communicating with the pressure chamber, which ejects the ink from the pressure chamber, an ink-jet head having an actuator that increases and decreases the capacity of the pressure chamber, and a driving signal generation unit that supplies the actuator with a driving signal to eject an ink drop from the nozzle. When no ink is ejected from the nozzle, the actuator is supplied with a very low pressure driving signal to increase the capacity of the pressure chamber and then return the increased capacity to an original size. The pulse width of the very low pressure driving signal is about twice as long as a pressure propagation time period during which a pressure wave in the ink propagates through the pressure chamber.

Abstract: There is provided an ink jet head driving method for applying a drive pulse to an actuator to change capacities of a plurality of pressure chambers in which ink has been filled, ejecting an ink droplet from a nozzle formed in communication with the pressure chamber to print onto a printing medium, and moreover, continuously ejecting a plurality of liquid droplets to carry out gradation printing according to the number of liquid droplets, the method including making control so as to, in the case where the number of the liquid droplets is smaller than a predetermined number, apply a boost pulse to amplify a pressure vibration of the pressure chamber prior to a drive pulse for ejecting a first liquid droplet, and in the case where the number of liquid droplets is equal to or greater than the predetermined number, disable applying of the boost pulse.

Abstract: An ink-jet recording apparatus includes a pressure chamber that contains ink, a nozzle communicating with the pressure chamber, which ejects the ink from the pressure chamber, an ink-jet head having an actuator that increases and decreases the capacity of the pressure chamber, and a driving signal generation unit that supplies the actuator with a driving signal to eject an ink drop from the nozzle. When no ink is ejected from the nozzle, the actuator is supplied with a very low pressure driving signal to increase the capacity of the pressure chamber and then return the increased capacity to an original size. The pulse width of the very low pressure driving signal is about twice as long as a pressure propagation time period during which a pressure wave in the ink propagates through the pressure chamber.

Abstract: An ink-jet device is composed of a print head for ejecting ink as drops from an ink chamber to print a dot at a tone-level corresponding to an amount of ejected ink, and a drive unit for driving the print head by successively supplying a variable number of drive pulses each of which allows the ink chamber to generate pressure of ejecting a single drop of ink. Particularly, the drive unit includes a drive IC for generating a fixed number of drive pulses and shortening the supply cycle of the drive pulses such that the pressure of the ink chamber is gradually increased to finally eject a drop of ink when the dot is printed in monotone.

Abstract: An ink-jet head is formed by partitioning a plurality of ink chambers made from piezoelectric members from each other. Ink chambers which emit ink and dummy ink chambers which do not emit ink are arranged alternately, and ink is supplied to the ink chambers from a common ink chamber. This ink head is used to sequentially perform emission of an ink drop from the ink chambers for a plurality of times, to achieve gradation printing, while the emission speed of the ink drops is gradually increased such that ink drops emitted later are merged with ink drops emitted earlier thereby to form a one-dot liquid drop. In this case, where adjacent ink chambers with a dummy ink chamber inserted therebetween are simultaneously driven, timings of drive pulse voltages q1 and q2 applied to both of the adjacent ink chambers are shifted from each other such that the pressure in one of the adjacent ink chambers is decreased when the pressure in the other of the adjacent ink chamber is increased.

Abstract: In a multi-drop system, a drive pulse voltage for increasing a volume of an ink chamber is applied for a time of AL, a drive pulse voltage for decreasing the volume of the ink chamber is subsequently applied for a time of 2AL, application of the drive pulse voltage is thereafter paused for a time of AL, and the same timing operation is thereafter repeated again to perform emission of an ink drop a plurality of times, where AL is a time required for a pressure wave in an ink chamber to be transmitted from an end to the other end in the ink emission direction. The drive pulse voltage for emitting a last ink drop forming a part of a one-dot liquid drop is applied for a time of 2AL, application of the drive pulse voltage is thereafter paused for a time of AL, and a dumping pulse voltage is thereafter applied in a direction in which the volume of the ink chamber is decreased.

Abstract: A sheet passage is formed so as to extend from a sheet feed position via a printing position to a sheet delivery position, delivery rollers driven by a driving unit are disposed between the printing position and the sheet delivery position on the sheet passage, pressure rollers are disposed on one side of the sheet passage so as to be in contact respectively with the delivery rollers disposed on the other side of the sheet passage, a back sheet guide is disposed between the delivery rollers and the sheet delivery position, and a printed sheet delivered by the delivery rollers and guided by the back sheet guide is transferred to a printed sheet storage unit by sheet transfer arms.