Brother Kogyo Kabushiki-Kaisha

Kyocera Corporation

Shin Ishikura

Manabu Hibi

Kenichi Satake

Naoto Iwao

Atsushi Hirota

Atsuo Sakaida

Hidetoshi Watanabe

Hiroshi Aida

Hisamitsu Sakai

Chitoshi Ueki

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. The individual liquid passage is designed so that Tc1 and Tc2 defined by predetermined expressions showing characteristics of the individual liquid passage satisfy a condition that Tc1/Tc2 is substantially not less than 4.7 and not more than 5.5.

Liquid ejection head and driving method thereof

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. It is preferred that a timing at which the controller changes voltage applied to one of the two adjacent element lines is different from a timing at which the controller changes voltage applied to the other of the two adjacent element lines.

Ink jet printer, method of controlling an ink jet printer, and computer program product for an ink jet printer

An inkjet printer whose ink discharge characteristic will rarely change even when used for a long period of time is developed. The inkjet printer has a pressure chamber and a piezoelectric actuator and a controller. The piezoelectric actuator has a first electrode, a first piezoelectric film, a second electrode, a second piezoelectric film, and a third electrode, and they are laminated together in this order. The piezoelectric actuator forms a portion of the wall defining the pressure chanter. The controller applies ink discharge signal between the first and second electrode, ink discharge signal comprises advanced voltage change from a predetermined voltage to the lower voltage and subsequent voltage change from the lower voltage to the predetermined voltage. Ink can be effectively discharged by applying the ink discharge signal, but the ink discharge signal could change piezoelectric characteristic in the second piezoelectric film due to the deformation of the first piezoelectric film. The additional signal applying the second piezoelectric film via the second and the third electrode can reduce the changes of the piezoelectric characteristic. As a result, changes of ink discharge characteristic can be prevented.

Inkjet printer and a method of manufacturing an inkjet printer

A controller controls a pressurizing actuator in such a manner that a pressure chamber changes from a first state where a volume of the pressure chamber is Vto a second state where the volume is Vlarger than Vand then returns from the second to the first state to cause ink to be ejected from an ejection opening, that a time length Tvfrom a time point at which the pressure chamber starts to change from the first to the second state to a time point at which the pressure chamber is in the second state becomes 33% or more of a characteristic vibration period Td of ink filled in a first ink passage extending from an outlet of the pressure chamber to the ejection opening, and that the time length Tvbecomes 83% or less of the characteristic vibration period Td.

Inkjet recording apparatus and control method for the same

An actuator can selectively switch a volume of a pressure chamber between a first state Vand a second state V, which is greater than V. 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 fromto. 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.

Inkjet recording apparatus and method of determining control condition in the apparatus

An inkjet head includes a passage unit and an actuator unit. The passage unit includes a common ink chamber and an individual ink passage leading from an outlet of the common ink chamber through a pressure chamber to an ejection port. The actuator unit can selectively take a first state in which the volume of the pressure chamber is Vand a second state in which the volume of the pressure chamber is Vlarger than V. The actuator unit changes from the first state into the second state and then returns to the first state to eject ink from the ejection port. The individual ink passage is formed such that the volume Vd of a partial passage in the individual ink passage corresponding to a region from an outlet of the pressure chamber to the ejection port, and the volume Vc of the individual ink passage, satisfy a condition that Vd/Vc is not less than 0.12 and not more than 0.40.

Inkjet head

An actuator can selectively take a first state wherein a volume of a pressure chamber is Vand a second state wherein the volume of the pressure chamber is Vlarger than V. The actuator changes from the first state to the second state and then returns to the first state to eject ink from an ejection port. A proper oscillation period Ts of an oscillation generated by integral deformation of the actuator and the pressure chamber when ink is ejected from the ejection port, and a proper oscillation period Td of ink filling up a first partial passage leading from an outlet of the pressure chamber to the ejection port in an individual ink passage, satisfy a condition that Ts/Td is not less than 0.36 and not more than 0.90; or not less than 1.1 and not more than 1.7.

To provide an inkjet head that maintains a reliable electric connection between a flow channel unit and a common electrode of an actuator unit, a flow channel unit is provided with a cavity formed on an attachment surface of flow channel unit to attach to an actuator unit, and the actuator unit is provided with a contact terminal connected to the common electrode and formed at a position facing the cavity when the flow channel unit and the actuator unit are attached. The common electrode is reliably connected to the flow channel unit through the contact terminal and a conductive material filling the cavity.

Inkjet head and a method of manufacturing thereof

An inkjet head has: a channel unit having a plurality of nozzles and a plurality of pressure chambers respectively communicating with the nozzles; and an actuator unit on the channel unit and having a piezoelectric sheet, a plurality of individual electrodes respectively arranged to positionally correspond to the pressure chambers respectively and a common electrode sandwiching the piezoelectric sheet together with the plurality of individual electrodes. The actuator unit has a thickness of 20 &#x3bc;m to 100 &#x3bc;m and a surface roughness of the end face of the actuator unit including an intersection with channel unit and the actuator unit is 0.15 &#x3bc;m to 0.5 &#x3bc;m, and at least part of the end face is sealed by a resin film.

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.

Method of testing a droplet discharge device

A method for manufacturing an inkjet head includes producing a flow path unit, producing an actuator unit, bonding the actuator unit with the flow path unit to produce a bonded structure; measuring a frequency characteristic of impedance of the piezoelectric structure of the bonded structure in each of regions facing at least one of the pressure chambers, and determining whether or not the bonded structure is a good product on a basis of at least one of a distribution of (Fa&#x2212;Fr) in the plural regions where Fa represents antiresonance frequency of each region at which impedance of each region are maximal and Fr represents resonance frequency of each region at which impedance of each region is minimal, a distribution of Fr in the plural regions, and a distribution of Zr in the plural regions, where Zr represents impedance of each region at the resonance frequency of each region.

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Kokubu, Japan

Shin Ishikura