Liquid ejection head and liquid ejection apparatus

Patent metadata

Field	Value
Publication number	US-11602933-B2
Application number	US-202117191524-A
Country	US
Kind code	B2
Filing date	Mar 3, 2021
Priority date	May 15, 2020
Publication date	Mar 14, 2023
Grant date	Mar 14, 2023

Abstract

According to one embodiment, a liquid ejection head includes a pressure chamber that contains a liquid, an actuator to change the pressure in the pressure chamber according to an applied drive signal, and a drive circuit to apply a first drive signal to the actuator when a single droplet is to be ejected from the pressure chamber and a second drive signal to the actuator when two or more droplets are to be ejected in series from the pressure chamber. The first drive signal has a first auxiliary pulse before a first ejection pulse. The second drive signal has a second auxiliary pulse before the first ejection pulse. A pulse width of the first auxiliary pulse is greater than a pulse width of the second auxiliary pulse.

First claim

What is claimed is:

1. A liquid ejection head, comprising:
a pressure chamber configured to contain a liquid;
an actuator configured to change pressure of the pressure chamber according to an applied drive signal; and
a drive circuit configured to apply a first drive signal to the actuator when a single droplet is to be ejected from the pressure chamber and apply a second drive signal to the actuator when two or more droplets are to be ejected in series from the pressure chamber, wherein
the first drive signal includes a first auxiliary pulse before a first ejection pulse,
the second drive signal includes a second auxiliary pulse before the first ejection pulse, a pulse width of the first auxiliary pulse being greater than a pulse width of the second auxiliary pulse, and
a pulse width of a second ejection pulse in the second drive signal is less than a pulse width of the first ejection pulse.

2. The liquid ejection head according to claim 1 , wherein, in the second drive signal, pulse widths of subsequent ejection pulses after the second ejection pulse are less than the pulse width of the first ejection pulse.

3. The liquid ejection head according to claim 2 , wherein, in the second drive signal, the pulse widths of subsequent ejection pulses after the second ejection pulse are greater than the pulse width of the second ejection pulse.

4. The liquid ejection head according to claim 3 , wherein, in the second drive signal, the pulse widths of subsequent ejection pulses after the second ejection pulse are equal to one another.

5. The liquid ejection head according to claim 2 , wherein, in the second drive signal, the pulse widths of subsequent ejection pulses after the second ejection pulse are equal to one another.

6. The liquid ejection head according to claim 1 , wherein
the second drive signal includes four or more ejection pulses,
a pulse width of the third ejection pulse in the second drive signal is greater than the pulse width of the second ejection pulse, but less than the pulse width of the first ejection pulse in the second drive signal, and
pulse widths of the third and subsequent ejection pulses are equal to each other.

7. The liquid ejection head according to claim 1 , wherein
the drive circuit is configured to vary a drive voltage of the first and second drive signals, and
the drive circuit is configured to vary the pulse widths of the first and second auxiliary pulses.

8. The liquid ejection head according to claim 1 , wherein the actuator is piezoelectric.

9. A liquid ejection apparatus, comprising:
a pressure chamber configured to contain a liquid;
a liquid supply device configured to supply the liquid to the pressure chamber;
an actuator configured to change pressure of the pressure chamber according to an applied drive signal; and
a drive circuit configured to apply a first drive signal to the actuator when a single droplet is to be ejected from the pressure chamber and apply a second drive signal to the actuator when two or more droplets are to be ejected in series from the pressure chamber, wherein
the first drive signal includes a first auxiliary pulse before a first ejection pulse,
the second drive signal includes a second auxiliary pulse before the first ejection pulse, a pulse width of the first auxiliary pulse being greater than a pulse width of the second auxiliary pulse, and
a pulse width of a second ejection pulse in the second drive signal is less than a pulse width of the first ejection pulse.

10. The liquid ejection apparatus according to claim 9 , wherein, in the second drive signal, pulse widths of subsequent ejection pulses after the second ejection pulse are less than the pulse width of the first ejection pulse.

11. The liquid ejection apparatus according to claim 10 , wherein, in the second drive signal, the pulse widths of subsequent ejection pulses after the second ejection pulse are greater than the pulse width of the second ejection pulse.

12. The liquid ejection apparatus according to claim 11 , wherein, in the second drive signal, the pulse widths of subsequent ejection pulses after the second ejection pulse are equal to one another.

13. The liquid ejection apparatus according to claim 10 , wherein, in the second drive signal, the pulse widths of subsequent ejection pulses after the second ejection pulse are equal to one another.

14. The liquid ejection apparatus according to claim 9 , wherein
the second drive signal includes four or more ejection pulses,
a pulse width of the third ejection pulse in the second drive signal is greater than the pulse width of the second ejection pulse, but less than the pulse width of the first ejection pulse in the second drive signal, and
pulse widths of the third and subsequent ejection pulses are equal to each other.

15. The liquid ejection apparatus according to claim 9 , wherein the actuator is piezoelectric.

16. A inkjet printer, comprising:
an inkjet head including a pressure chamber configured to contain an ink;
an ink cartridge configured to supply the ink to the inkjet head;
an actuator configured to change pressure of the pressure chamber according to an applied drive signal; and
a drive circuit configured to apply a first drive signal to the actuator when a single droplet is to be ejected from the pressure chamber and apply a second drive signal to the actuator when two or more droplets are to be ejected in series from the pressure chamber, wherein
the first drive signal includes a first auxiliary pulse before a first ejection pulse,
the second drive signal includes a second auxiliary pulse before the first ejection pulse, a pulse width of the first auxiliary pulse being greater than a pulse width of the second auxiliary pulse, and
a pulse width of a second ejection pulse in the second drive signal is less than a pulse width of the first ejection pulse.

17. The inkjet printer according to claim 16 , wherein, in the second drive signal, pulse widths of subsequent ejection pulses after the second ejection pulse are less than the pulse width of the first ejection pulse, but greater than the pulse width of the second ejection pulse.

18. The inkjet printer according to claim 17 , wherein, in the second drive signal, the pulse widths of subsequent ejection pulses after the second ejection pulse are greater than the pulse width of the second ejection pulse.

19. The inkjet printer according to claim 18 , wherein, in the second drive signal, the pulse widths of subsequent ejection pulses after the second ejection pulse are equal to one another.

20. The inkjet printer according to claim 16 , wherein
the drive circuit is configured to vary a drive voltage of the first and second drive signals, and
the drive circuit is configured to vary the pulse widths of the first and second auxiliary pulses.

Assignees

• Toshiba Tec Kk

Inventors

• Wong Mengfei
• Kusunoki Ryutaro

Classifications

• B41J2/04541

  Specific driving circuit · CPC title

• B41J2/04581

  controlling heads based on piezoelectric elements · CPC title

• B41J2002/1437

  Back shooter · CPC title

• B41J2/04588 Primary

  using a specific waveform · CPC title

• B41J2/04596

  Non-ejecting pulses · CPC title