Fujifilm Corporation

Ricoh Company, Ltd.

Ryuji Tsukamoto

Takamichi Fujii

Kenichi Kodama

Kohta Akiyama

Takashi Kinokuni

Masaya Shingyoh

A drive controller includes circuitry. The circuitry generates multiple types of drive pulses to be applied to a driver of a liquid discharge head including a valve to open and close a discharge port, and applies the multiple types of drive pulses to the driver to cause the driver to move the valve to open and close the discharge port. Each of the multiple types of drive pulses causes the valve to move away from the discharge port at a valve-opening speed to open the discharge port, keep opening the discharge port for an open time, and move toward the discharge port at a valve-closing speed to close the discharge port. Further, the circuitry generates the multiple types of drive pulses, the open time and the valve-closing speed of which are different, and changes the valve-closing speed according to the open time.

Drive controller, head unit, and liquid discharge apparatus

A liquid discharge head includes: a diaphragm having a nozzle; a substrate including a pressure chamber communicating with the nozzle; a piezoelectric body over the diaphragm, the piezoelectric body configured to deform at least a part of an edge of the nozzle; and a vibration absorbing portion in the diaphragm.

Liquid discharge head, liquid discharge device, and liquid discharge apparatus

A liquid discharge apparatus includes a liquid discharge head including a nozzle plate including at least one nozzle configured to discharge liquid; at least one individual liquid chamber respectively communicating with the at least one nozzle; at least one individual supply channel respectively communicating with the at least one individual liquid chamber; and at least one individual collecting channel respectively communicating with the at least one individual liquid chamber. The apparatus further includes circuitry configured to store, in a memory, a backflow-inducing discharge amount at which the liquid in the individual collecting channel flows in a reverse direction toward the individual liquid chamber, in response to discharge of the liquid from the nozzle; and set a discharge amount from the nozzle equal to or greater than the backflow-inducing discharge amount, to cause the liquid to flow in the reverse direction in the individual collecting channel.

Liquid discharge apparatus

A liquid discharge head includes a plurality of nozzles, a plurality of individual liquid chambers, a plurality of liquid delivery channels, and a deformation unit. The plurality of nozzles discharges liquid. The plurality of individual liquid chambers is communicated with the plurality of nozzles. The plurality of liquid delivery channels is communicated with the plurality of individual liquid chambers. Each of the plurality of liquid delivery channels includes a channel portion at a partition wall between adjacent individual liquid chambers of the plurality of individual liquid chambers. The deformation unit deforms at least a portion of the channel portion.

An object of the invention is to prevent, both bubbles and particles from being generated, when circulating ink in an inkjet head. The object can be achieved by an ink circulation apparatus, including: an ink tank that accumulates radical polymerization-type UV-curing ink so as to be in contact with gas including at least oxygen; an inkjet head; oxygen removing means that removes oxygen from the radical polymerization-type UV-curing ink; and control means that changes a mode between a first mode of removing oxygen from the radical polymerization-type UV-curing ink by the oxygen removing means and a second mode of not removing oxygen from the radical polymerization-type UV-curing ink and changes a mode from the first mode to the second mode before electric power of the apparatus is cut off.

Ink circulation apparatus, ink circulation method and inkjet recording apparatus

An ink circulation apparatus, including: an ink tank that accumulates radical polymerization-type UV-curing ink; a supplying flow path that communicates with the ink tank and a supply port of an inkjet head; a supply pump that supplies the ink accumulated in the ink tank to the inkjet head; oxygen removing unit that removes oxygen from the ink to be supplied to the inkjet head; a discharging flow path that communicates with a discharge port of the inkjet head and the ink tank; a collecting pump that collects the ink to be discharged from the discharge port in the ink tank; and oxygen supplying unit that supplies oxygen to the ink to be collected in the ink tank.

A basic driving waveform which includes a plurality of jet pulses and a non-jet pulse just before the last jet pulse in one recording period is generated. A part of the pulses is removed from the basic driving waveform by maintaining at least the last jet pulse, and a driving signal that is applied to a discharge energy generation element is generated. In the case of using only the last jet pulse among the plurality of jet pulses is used for the jet, a first driving signal that includes the non-jet pulse just before the last jet pulse is generated. In the case of joining the last jet pulse and at least another jet pulse among the plurality of jet pulses to use the pulses for the jet, a second driving signal that is configured to remove the non-jet pulse is generated.

Device and method for driving liquid discharge head, liquid discharge apparatus, and ink-jet apparatus

A standard drive waveform contains, in one ejection cycle: a first ejection waveform group including at least one ejection waveform causing liquid to be ejected from a nozzle to form one dot of a maximum size; a first non-ejection waveform arranged after the first ejection waveform group; a second ejection waveform group including at least one ejection waveform causing the liquid to be ejected from the nozzle to form a dot of a minimum size; and a second non-ejection waveform arranged after the second ejection waveform group. At least one of the ejection waveforms is selected from one of the first and second ejection waveform groups in accordance with ejection data. When the selected ejection waveform belongs to the first ejection waveform group, the first non-ejection waveform is further selected. When the selected ejection waveform belongs to the second ejection waveform group, the second non-ejection waveform is further selected.

Inkjet ejection apparatus, inkjet ejection method, and inkjet recording apparatus

A method of manufacturing a piezoelectric element, includes: a heating step of heating a piezoelectric film to a temperature not lower than a temperature at which a coercive electric field of the piezoelectric film becomes not higher than 0 V; an electric field application step of applying, to the piezoelectric film, an applied electric field in an opposite direction to a direction of orientation of the piezoelectric film while maintaining the temperature to which the piezoelectric film is heated in the heating step; and a temperature lowering step of lowering a temperature of the piezoelectric film to a temperature, in degrees Celsius, not higher than &#x2153; of the Curie temperature while maintaining the applied electric field of a magnitude not lower than the coercive electric field applied to the piezoelectric film after the electric field application step, and then releasing the applied electric field applied to the piezoelectric film.

Method of manufacturing piezoelectric element and method of manufacturing liquid ejection head

A piezoelectric actuator includes: a piezoelectric layer formed by a film formation method so as to have orientation in a prescribed orientation direction; and a pair of electrodes, disposed on a same surface which is substantially perpendicular to the orientation direction of the piezoelectric layer, for applying to the piezoelectric layer an electric field in a direction substantially perpendicular to the orientation direction.

Piezoelectric actuator, method of manufacturing piezoelectric actuator, liquid ejection head, method of manufacturing liquid ejection head and image forming apparatus

A method for driving an inkjet head includes applying drive signals including an ejection signal used for ejecting ink and a non-ejection signal used for not ejecting the ink, to an actuator provided with a pressure chamber at a constant cycle so as to increase or reduce pressure in the pressure chamber in such a manner that the ink is ejected or not ejected from a nozzle connected with the pressure chamber, wherein: a waveform of the ejection signal includes a combination of an ejection pulse for causing a droplet of the ink to be ejected from the nozzle and a non-ejection pulse for not causing a droplet of the ink to be ejected from the nozzle, the ejection pulse of the waveform of the ejection signal includes a part for reducing the pressure in the pressure chamber and a part for increasing the reduced pressure in the pressure chamber.

Method and apparatus for driving inkjet head

A method of manufacturing a piezoelectric actuator includes a first polarization of a piezoelectric body; polishing the piezoelectric body; first heating step of heating the piezoelectric body to a temperature which is not lower than a Curie point of the piezoelectric body and performing a re-polarization of the piezoelectric body in a second polarization of the piezoelectric body having been heated in the first heating step.

Method of manufacturing a piezoelectric actuator

The method of manufacturing a piezoelectric element includes the steps of: a lower electrode forming step of forming a lower electrode on a surface of a substrate; a piezoelectric film deposition step of depositing a piezoelectric film made of a piezoelectric material by one of epitaxial growth and oriented growth onto a surface of the lower electrode reverse to a surface adjacent to the substrate; an upper electrode forming step of forming an upper electrode onto a surface of the piezoelectric film reverse to a surface adjacent to the lower electrode; and a polarization direction reversal step of reversing a polarization direction of the piezoelectric film by applying an alternating electric field of an intensity not lower than a coercive electric field of the piezoelectric material, between the upper electrode and the lower electrode, and then applying a direct electric field of an intensity not lower than the coercive electric field in a direction from the upper electrode toward the lower electrode.

A method of driving a piezoelectric actuator has the step of driving a piezoelectric actuator including a diaphragm, a lower electrode formed on one surface of the diaphragm, a piezoelectric film formed in epitaxial growth or oriented growth on an opposite side of the lower electrode to the diaphragm so as to be preferentially oriented in a (111) direction, and an upper electrode formed on an opposite side of the piezoelectric film to the lower electrode, by application of an electric field in a direction opposite to a direction of polarization of the piezoelectric film.

Method of driving piezoelectric actuator and method of driving liquid ejection head

The method of manufacturing a piezoelectric element includes: a lower electrode forming step of forming a lower electrode on a surface of a substrate; a piezoelectric film deposition step of depositing a piezoelectric film made of a piezoelectric material by one of epitaxial growth and oriented growth onto a surface of the lower electrode reverse to a surface adjacent to the substrate; an upper electrode forming step of forming an upper electrode onto a surface of the piezoelectric film reverse to a surface adjacent to the lower electrode; and a polarization direction reversal step of reversing a polarization direction of the piezoelectric film by maintaining, after the upper electrode forming step, a state for a prescribed duration where a temperature of the piezoelectric film is set to a first temperature while application of an electric field to the piezoelectric film in a direction from the upper electrode toward the lower electrode is performed, then keeping the application of the electric field while lowering the temperature of the piezoelectric film to a second temperature lower than the first temperature, and then stopping the application of the electric field.

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Kanagawa-ken, Japan

Ryuji Tsukamoto