Liquid ejecting apparatus, head unit, integrated circuit device for driving capacitive load, and capacitive load driving circuit

Patent metadata

Field	Value
Publication number	US-9399341-B2
Application number	US-201514829929-A
Country	US
Kind code	B2
Filing date	Aug 19, 2015
Priority date	Nov 25, 2014
Publication date	Jul 26, 2016
Grant date	Jul 26, 2016

Abstract

A liquid ejecting apparatus according to the invention includes: a modulation unit that generates a modulated signal which is obtained by pulse-modulating an original signal; a transistor that generates an amplified and modulated signal which is obtained by amplifying the modulated signal; a switching circuit; a low pass filter that generates a drive signal by demodulating the amplified and modulated signal; a feedback circuit that generates a feedback signal and feeds back the feedback signal to the modulation unit; a feedback terminal that electrically connects the modulation unit to the feedback circuit; a piezoelectric element that is displaced by the drive signal; a cavity; and a nozzle, in which a distance between the feedback terminal and a closest point to the feedback terminal in the modulation unit is shorter than a distance between the feedback terminal and a closest point to the feedback terminal in the switching circuit.

First claim

What is claimed is:

1. A liquid ejecting apparatus comprising:
a modulation unit that generates a modulated signal which is obtained by pulse-modulating an original signal;
a transistor that generates an amplified and modulated signal which is obtained by amplifying the modulated signal;
a switching circuit;
a low pass filter that generates a drive signal by demodulating the amplified and modulated signal;
a feedback circuit that generates a feedback signal based on the drive signal and feeds back the feedback signal to the modulation unit;
a feedback terminal that electrically connects the modulation unit to the feedback circuit;
a piezoelectric element that is displaced by the drive signal which is applied;
a cavity which is filled with a liquid therein, and whose internal volume is changed by displacement of the piezoelectric element; and
a nozzle that communicates with the cavity, and ejects the liquid in the cavity as droplets in accordance with change of the internal volume of the cavity,
wherein a distance between the feedback terminal and a closest point to the feedback terminal in the modulation unit is shorter than a distance between the feedback terminal and a closest point to the feedback terminal in the switching circuit.

2. The liquid ejecting apparatus according to claim 1 ,
wherein the switching circuit includes at least one of a gate driver that generates an amplification control signal which controls the transistor, based on the modulated signal, and a voltage boosting circuit.

3. The liquid ejecting apparatus according to claim 2 ,
wherein the switching circuit includes the gate driver and the voltage boosting circuit.

4. The liquid ejecting apparatus according to claim 2 ,
wherein the voltage boosting circuit is a charge pump circuit.

5. The liquid ejecting apparatus according to claim 1 ,
wherein the feedback circuit feeds back a signal in high frequency bandwidth of the drive signal as the feedback signal.

6. The liquid ejecting apparatus according to claim 1 ,
wherein an oscillation frequency of the modulated signal is equal to or higher than 1 MHz and is equal to or lower than 8 MHz.

7. A head unit comprising:
a modulation unit that generates a modulated signal which is obtained by pulse-modulating an original signal;
a transistor that generates an amplified and modulated signal which is obtained by amplifying the modulated signal;
a switching circuit;
a low pass filter that generates a drive signal by demodulating the amplified and modulated signal;
a feedback circuit that generates a feedback signal based on the driver signal and feeds back the feedback signal to the modulation unit;
a feedback terminal that electrically connects the modulation unit to the feedback circuit;
a piezoelectric element that is displaced by the drive signal which is applied;
a cavity which is filled with a liquid therein, and whose internal volume is changed by displacement of the piezoelectric element; and
a nozzle that communicates with the cavity, and ejects the liquid in the cavity as droplets in accordance with change of the internal volume of the cavity,
wherein a distance between the feedback terminal and a closest point to the feedback terminal in the modulation unit is shorter than a distance between the feedback terminal and a closest point to the feedback terminal in the switching circuit.

Assignees

• Seiko Epson Corp

Inventors

• Yamada Tomokazu

Classifications

• B41J2/04508

  aiming at correcting other parameters · CPC title

• B41J2/0455

  Details of switching sections of circuit, e.g. transistors · CPC title

• B41J2/04586

  controlling heads of a type not covered by groups B41J2/04575 - B41J2/04585, or of an undefined type · CPC title

• B41J2/04525 Primary

  reducing occurrence of cross talk · CPC title

• B41J2/04541 Primary

  Specific driving circuit · CPC title