Liquid ejecting apparatus

Patent metadata

Field	Value
Publication number	US-10875294-B2
Application number	US-201916284120-A
Country	US
Kind code	B2
Filing date	Feb 25, 2019
Priority date	Feb 26, 2018
Publication date	Dec 29, 2020
Grant date	Dec 29, 2020

Abstract

A driving circuit includes a comparator that compares a voltage of an original driving signal with a voltage of a feedback signal of a driving signal, transistors, and a control signal generating circuit that generates a gate signal to the transistor and a gate signal to the transistor. The control signal generating circuit controls to alternately switch on the transistors. Driving abilities of the transistors are switched to be lowered by insertion of capacitors by an adjustment circuit.

First claim

What is claimed is:

1. A liquid ejecting apparatus comprising:
a print head that includes a nozzle and a piezoelectric element displaced by being applied with a driving signal, and ejects a liquid from the nozzle by the displacement of the piezoelectric element;
a comparator that compares a voltage of an original driving signal with a voltage of a feedback signal which is a signal obtained by feeding back the driving signal;
a transistor pair that includes a first transistor having a first gate terminal and a second transistor having a second gate terminal, and outputs the driving signal;
a control signal generating circuit to which an output signal of the comparator is input, and which generates a first control signal for controlling a switching operation of the first transistor and a second control signal for controlling a switching operation of the second transistor such that the first transistor and the second transistor are alternately switched on; and
an element that changes an output characteristic of the first transistor or the second transistor between the first gate terminal or the second gate terminal and the control signal generating circuit.

2. The liquid ejecting apparatus according to claim 1 ,
wherein the output characteristic is a characteristic of a voltage at which the first transistor or the second transistor is switched on with respect to a voltage of the first control signal or the second control signal.

3. The liquid ejecting apparatus according to claim 1 ,
wherein the element is
a first capacitor that is capable of being switched to an electric connection state or an electric disconnection state between the first gate terminal and a drain terminal of the first transistor, and
a second capacitor that is capable of being switched to an electric connection state or an electric disconnection state between the second gate terminal and a drain terminal of the second transistor.

4. The liquid ejecting apparatus according to claim 1 ,
wherein the element is
a first resistive element that is capable of being switched to an electric connection state or an electric disconnection state between the first gate terminal and a drain terminal of the first transistor, and
a second resistive element that is capable of being switched to an electric connection state or an electric disconnection state between the second gate terminal and a drain terminal of the second transistor.

5. The liquid ejecting apparatus according to claim 1 ,
wherein the element is a switch that switches driving abilities of the first transistor and the second transistor.

6. The liquid ejecting apparatus according to claim 1 ,
wherein the driving signal has
a first region in which the first transistor and the second transistor are alternately switched on so that a voltage of the driving signal increases,
a second region in which the first transistor and the second transistor are alternately switched on so that the voltage of the driving signal decreases,
a third region following the second region between the first region and the second region, and
a fourth region following the first region between the first region and the second region, and
wherein when the voltage of the driving signal belongs to the third region or the fourth region, the first control signal or the second control signal is supplied to the first gate terminal or the second gate terminal through the element.

7. The liquid ejecting apparatus according to claim 6 ,
wherein an oscillation width, which is a difference between a voltage maximum value of the driving signal when the first transistor is switched on and a voltage minimum value of the driving signal when the second transistor is switched on in the third region, is smaller than an oscillation width, which is a difference between a voltage maximum value of the driving signal when the first transistor is switched on and a voltage minimum value of the driving signal when the second transistor is switched on in the fourth region.

8. The liquid ejecting apparatus according to claim 1 ,
wherein in a period during which a voltage of the original driving signal increases, the first transistor and the second transistor are alternately switched on.

9. The liquid ejecting apparatus according to claim 1 ,
wherein in a period during which a voltage of the original driving signal decreases, the first transistor and the second transistor are alternately switched on.

10. The liquid ejecting apparatus according to claim 1 ,
wherein in a period during which a voltage of the original driving signal is constant, the first transistor and the second transistor are alternately switched on.

11. The liquid ejecting apparatus according to claim 1 ,
wherein the print head includes more than 600 nozzles arranged at a density of 300 or more per inch.

12. A liquid ejecting apparatus comprising:
a print head that includes a nozzle and a piezoelectric element displaced by being applied with a driving signal, and ejects a liquid from the nozzle by the displacement of the piezoelectric element;
a comparator that compares a voltage of an original driving signal with a voltage of a feedback signal which is a signal obtained by feeding back the driving signal;
a transistor pair that includes a first transistor having a first gate terminal and a second transistor having a second gate terminal, and outputs the driving signal;
a control signal generating circuit to which an output signal of the comparator is input, and which generates a first control signal for controlling a switching operation of the first transistor and a second control signal for controlling a switching operation of the second transistor such that the first transistor and the second transistor are alternately switched on; and
a gate control circuit that is provided between the first transistor and the second transistor and the control signal generating circuit, and is electrically connected to the first gate terminal and the second gate terminal.

Assignees

• Seiko Epson Corp

Inventors

• Abe Akira

Classifications

• B41J2/04593

  Dot-size modulation by changing the size of the drop · CPC title

• B41J2/04596

  Non-ejecting pulses · CPC title

• B41J2/04581

  controlling heads based on piezoelectric elements · CPC title

• H03K5/24 Primary

  the characteristic being amplitude · CPC title

• B41J2/04588

  using a specific waveform · CPC title