Waveform generating device and ink jet recording apparatus
According to one embodiment, a waveform generating device includes a head driver configured to apply a driving signal to an actuator to discharge ink from a pressure chamber connected to a nozzle, the driving signal including a first portion for reducing an ink pressure in the pressure chamber and a second portion for increasing the ink pressure in the pressure chamber. The second portion is increased in potential by a first potential increase when ink pressure in the pressure chamber is at a maxima and the second portion is further increased in potential by a second potential increase when the ink pressure of the pressure chamber is at a negative value after the first potential increase.
1. A waveform generating device, comprising:
a head driver configured to apply a driving signal to an actuator to discharge ink from a pressure chamber connected to a nozzle, the driving signal including a first portion for reducing an ink pressure in the pressure chamber and a second portion for increasing the ink pressure in the pressure chamber, wherein
the second portion is increased in potential by a first potential increase when ink pressure in the pressure chamber is at a maxima, and
the second portion is further increased in potential by a second potential increase when the ink pressure of the pressure chamber is at a negative value after the first potential increase.
2. The waveform generating device according to claim 1 , wherein the second portion is reduced in potential in a first stage by a first potential reduction and then again in a second stage by a second potential reduction.
3. The waveform generating device according to claim 2 , wherein, when a time from a start of the second portion to the first potential reduction is set to P, and a time from the first potential reduction to the second potential reduction is set to v, the driving signal satisfies the following:
P=− 0.6 v+ 2.63.
4. The waveform generating device according to claim 1 , wherein the driving signal includes applying a zero potential for an interval between an end of the first portion and a start of the second portion.
5. The waveform generating device according to claim 1 , wherein
the pressure chamber is fluidly connected to an ink chamber, and
a time length of the first portion is equal to a half time of a natural vibration period of ink in the ink chamber.
6. The waveform generating device according to claim 5 , wherein the second portion is increased in potential by the second potential increase after a time equal to the half time of the natural vibration period elapses after the second potential increase.
7. The waveform generating device according to claim 5 , wherein the second portion is reduced in potential by a first potential reduction after between 1.3 times and 1.6 times the half time of the natural vibration period of the ink in the ink chamber from a start of the second portion.
8. An ink jet recording apparatus, comprising:
a nozzle plate having a nozzle;
an actuator configured to change a pressure of a pressure chamber connected to the nozzle; and
a head driver configured to apply a driving signal to an actuator to discharge ink from the pressure chamber connected to the nozzle, the driving signal including a first portion for reducing an ink pressure in the pressure chamber and a second portion for increasing the ink pressure in the pressure chamber, wherein
the second portion is increased in potential by a first potential increase when ink pressure in the pressure chamber is at a maxima, and
the second portion is further increased in potential by a second potential increase when the ink pressure of the pressure chamber is at a negative value after the first potential increase.
9. The ink jet recording apparatus according to claim 8 , wherein the second portion is reduced in potential in a first stage by a first potential reduction and then again in a second stage by a second potential reduction.
10. The ink jet recording apparatus according to claim 9 , wherein, when a time from a start of the second portion to the first potential reduction is set to P, and a time from the first potential reduction to the second potential reduction is set to v, the driving signal satisfies the following:
P=− 0.6 v+ 2.63.
11. The ink jet recording apparatus according to claim 8 , wherein the driving signal includes applying a zero potential for an interval between an end of the first portion and a start of the second portion.
12. The ink jet recording apparatus according to claim 8 , wherein
the pressure chamber is fluidly connected to an ink chamber, and
a time length of the first portion is equal to a half time of a natural vibration period of ink in the ink chamber.
13. The ink jet recording apparatus according to claim 12 , wherein the second portion is increased in potential by the second potential increase after a time equal to the half time of the natural vibration period elapses after the second potential increase.
14. The ink jet recording apparatus according to claim 12 , wherein the second portion is reduced in potential by a first potential reduction after between 1.3 times and 1.6 times the half time of the natural vibration period of the ink in the ink chamber from a start of the second portion.
15. An inkjet head driving method, comprising:
applying a driving signal to an actuator to discharge ink from a pressure chamber connected to a nozzle, the driving signal including a first portion for reducing an ink pressure in the pressure chamber and a second portion for increasing the ink pressure in the pressure chamber, wherein
the second portion is increased in potential by a first potential increase when ink pressure in the pressure chamber is at a maxima, and
the second portion is further increased in potential by a second potential increase when the ink pressure of the pressure chamber is at a negative value after the first potential increase.
16. The inkjet head driving method according to claim 15 , wherein the second portion is reduced in potential in a first stage by a first potential reduction and then again in a second stage by a second potential reduction.
17. The inkjet head driving method according to claim 16 , wherein, when a time from a start of the second portion to the first potential reduction is set to P, and a time from the first potential reduction to the second potential reduction is set to v, the driving signal satisfies the following:
P=− 0.6 v+ 2.63.
18. The inkjet head driving method according to claim 15 , wherein the driving signal includes applying a zero potential for an interval between an end of the first portion and a start of the second portion.
19. The inkjet head driving method according to claim 15 , wherein
the pressure chamber is fluidly connected to an ink chamber, and
a time length of the first portion is equal to a half time of a natural vibration period of ink in the ink chamber.
20. The inkjet head driving method according to claim 19 , wherein the second portion is increased in potential by the second potential increase after a time equal to the half time of the natural vibration period elapses after the second potential increase.