Toshiba Tec Kabushiki Kaisha

Riso Technologies Corporation

Meng Fei Wong

Ryutaro Kusunoki

Shuhei Yokoyama

Ryuichi Arai

Yuji Shinomiya

According to an embodiment, an inkjet head includes a nozzle that ejects ink, an ink pressure chamber that connects to the nozzle, an actuator that changes a volume of the ink pressure chamber, and an actuator driving circuit that drives the actuator with a driving waveform. The driving waveform includes an ejection pulse portion that changes from a first voltage to a second voltage at which the ink pressure chamber expands and then changes from the second voltage to a third voltage at which the ink pressure chamber contracts so as to eject the ink from the nozzle. The third voltage is between that of the first and second voltages in potential level. The potential difference between the second and third voltages is greater than the potential difference between the third and first voltages.

Inkjet head

A liquid ejection head includes a nozzle for ejecting a droplet of a liquid, a pressure chamber connected to the nozzle, an actuator for changing a volume of the chamber according to a voltage signal, and a drive circuit generating the signal for ejecting n droplets, where n is an integer of 3 or more. The signal includes (n−1) ejection pulses, comprising a first pulse lowering the voltage signal to a first value to expand the chamber and then to a second value to contract the chamber, and a second pulse lowering the voltage signal to the first value and then to a third value higher than the second value. The pulses are input at intervals of 0.8λ to 1.2λ, where λ is a primary natural vibration period of the chamber filled with the liquid.

Liquid ejection head

A liquid ejection device includes a liquid supply unit, an array of nozzles arranged in a matrix and through which liquid is ejected, actuators each connected to one of the nozzles, and a circuit configured to output signals to the actuators according to delay times that are predetermined in a matrix corresponding to the matrix of the array. The delay times include (k+l&#x2212;1) or more different delay times where the matrix thereof has k columns and l rows. The matrix is defined such that a difference of two adjacent delay times in each of column and row directions is an odd multiple of a half cycle of a natural vibration period of the liquid, and between two adjacent columns and rows, two or more different delay time differences exist between each pair of corresponding delay times of the adjacent columns and rows, respectively.

Liquid ejection device and image forming apparatus

An inkjet head includes a pressure chamber storing ink, a nozzle communicating with the chamber, an actuator ejecting the ink through the nozzle by changing a volume of the chamber, and a circuit outputting a drive signal to the actuator with a drive waveform having a cycle based on a number of gradation levels being used for printing. When printing is performed using three or more gradation levels, the circuit outputs the signal that has a multi-drop drive waveform including two or more first waveforms for ejecting first to (n&#x2212;1)-th droplets of the ink where n is equal to or greater than 3, a second waveform for ejecting an n-th droplet of the ink, and an intermediate time between the first waveform for ejecting the (n&#x2212;1)-th droplet and the second waveform for ejecting the n-th droplet. The intermediate time is longer than a time between two adjacent first waveforms.

According to one embodiment in an inkjet head, the common electrodes for all the actuators, without overlapping with the first wiring pattern formed by individual electrodes, are connected to a second wiring pattern that passes between the outer peripheral portion of piezoelectric bodies, and a third wiring pattern that extends in a direction different from a direction of the second wiring pattern. The first wiring pattern and the third wiring pattern are electrically insulated at intersections thereof.

Ink jet head and ink jet recording apparatus

An ink jet head includes a substrate having a pressure chamber formed therein, the pressure chamber being in communication with a nozzle through which ink is to be discharged, a first plate that is deformable to change a volume of the pressure chamber, and a second plate between the first plate and the pressure chamber, that stretches in response to an electric signal applied thereto. The second plate contracts in an in-plane direction to cause the first plate to deform and thereby the volume of the pressure chamber to be enlarged, when the electric signal is applied, and the second plate returns to an original shape thereof to cause the first plate to return to an original shape thereof and thereby the volume of the pressure chamber to return to an original volume thereof, when the electric signal is no longer applied.

Ink jet head having prolonged lifetime

An ink jet head includes a pressure chamber connected to a nozzle, an actuator configured to cause liquid in the pressure chamber to be ejected from the nozzle by deforming a wall of the pressure chamber, and a drive circuit configured to apply voltage to the actuator to drive the actuator. When a droplet of the liquid is ejected from the nozzle, the voltage applied to the actuator is changed from a first value to a second value that causes the pressure chamber to expand, and then changed from a third value that is equal to the second value or between the first value and the second value to the first value after a time period &#x3bb;, which is a primary natural oscillation period of the actuator when the pressure chamber and the nozzle are filled with the liquid.

Ink jet head and ink jet apparatus having the same

According to one embodiment in an ink jet head, the common electrodes for all the actuators, without overlapping with the first wiring pattern formed by individual electrodes, are connected to a second wiring pattern that passes between the outer peripheral portion of piezoelectric bodies, and a third wiring pattern that extends in a direction different from a direction of the second wiring pattern. The first wiring pattern and the third wiring pattern are electrically insulated at intersections thereof.

Growing community of inventors

Mishima Shizuoka, Japan

Meng Fei Wong