LIQUID EJECTING APPARATUS, HEAD UNIT, INTEGRATED CIRCUIT DEVICE FOR DRIVING CAPACITIVE LOAD, AND CAPACITIVE LOAD DRIVING CIRCUIT

• US 20160144616A1
• Filed: 08/19/2015
• Published: 05/26/2016
• Est. Priority Date: 11/25/2014
• Status: Active Grant

• Current Assignee: Seiko Epson Corporation (Seiko Group)
• Original Assignee: Seiko Epson Corporation (Seiko Group)
• Inventors: YAMADA, Tomokazu
• Granted Patent: US 9,545,789 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: B41J 2/04501 Control methods or devices therefor, e.g. driver circuits, control circuits
• CPC Class Codes: B41J 2/04541 Specific driving circuit
• CPC Class Codes: B41J 2/04548 Details of power line section of control circuit
• CPC Class Codes: B41J 2/04581 controlling heads based on piezoelectric elements
• CPC Class Codes: B41J 2/04586 controlling heads of a type not covered by groups B41J2/04575 - B41J2/04585, or of an undefined type
• CPC Class Codes: B41J 2/04588 using a specific waveform
• CPC Class Codes: B41J 2/04593 Dot-size modulation by changing the size of the drop
• CPC Class Codes: B41J 2/04596 Non-ejecting pulses

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 gate driver that generates an amplification control signal, based on the modulated signal; a transistor that generates an amplified and modulated signal which is obtained by amplifying the modulated signal, based on the amplification control signal; a low pass filter that generates a drive signal by demodulating the amplified and modulated signal; a piezoelectric element that is displaced by the drive signal which is applied; a first power supply unit that applies a signal to a terminal of the piezoelectric element, other than a terminal to which the drive signal is applied; a cavity; and a nozzle, wherein the gate driver and the first power supply unit are connected to a common ground terminal.

Claims

1. A liquid ejecting apparatus comprising:

a modulation unit that generates a modulated signal which is obtained by pulse-modulating an original signal;

a gate driver that generates an amplification control signal, based on the modulated signal;

a transistor that generates an amplified and modulated signal which is obtained by amplifying the modulated signal, based on the amplification control signal;

a low pass filter that generates a drive signal by demodulating the amplified and modulated signal;

a piezoelectric element that is displaced by the drive signal which is applied;

a first power supply unit that applies a signal to a terminal of the piezoelectric element, other than a terminal to which the drive signal 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 the gate driver and the first power supply unit are connected to a common ground terminal.

2. The liquid ejecting apparatus according to claim 1,

wherein the gate driver includes

a first gate driver;

and

a second gate driver that operates at a potential side lower than that of the first gate driver, and

wherein the second gate driver and the first power supply unit are connected to the common ground terminal.

3. The liquid ejecting apparatus according to claim 1, further comprising:

a voltage boosting circuit that supplies a power supply voltage to the gate driver,

wherein the gate driver, the first power supply unit and the voltage boosting circuit are connected to the common ground terminal.

4. The liquid ejecting apparatus according to claim 3,

wherein the first power supply unit and the voltage boosting circuit are adjacently positioned.

5. The liquid ejecting apparatus according to claim 3,

wherein the voltage boosting circuit is a charge pump circuit.

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 gate driver that generates an amplification control signal, based on the modulated signal;

a transistor that generates an amplified and modulated signal which is obtained by amplifying the modulated signal, based on the amplification control signal;

a low pass filter that generates a drive signal by demodulating the amplified and modulated signal;

a piezoelectric element that is displaced by the drive signal which is applied;

a first power supply unit that applies a signal to a terminal of the piezoelectric element, other than a terminal to which the drive signal 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 the gate driver and the first power supply unit are connected to a common ground terminal.

8. An integrated circuit device for driving a capacitive load comprising:

a modulation unit that generates a modulated signal which is obtained by pulse-modulating an original signal;

a gate driver that generates an amplification control signal based on the modulated signal, and outputs the amplification control signal to an output circuit which generates a drive signal based on the amplification control signal and outputs the drive signal to a capacitive load; and

a first power supply unit that applies a signal to a terminal of the capacitive load, other than a terminal to which the drive signal is applied,

wherein the gate driver and the first power supply unit are connected to a common ground terminal.

9. A capacitive load driving circuit comprising:

a modulation unit that generates a modulated signal which is obtained by pulse-modulating an original signal;

a gate driver that generates an amplification control signal, based on the modulated signal;

a transistor that generates an amplified and modulated signal which is obtained by amplifying the modulated signal, based on the amplification control signal;

a low pass filter that generates a drive signal by demodulating the amplified and modulated signal;

a capacitive load to which the drive signal is applied; and

a first power supply unit that applies a signal to a terminal of the capacitive load, other than a terminal to which the drive signal is applied,

wherein the gate driver and the first power supply unit are connected to a common ground terminal.