JPS613752A - Ink-on-demand ink jet head drive circuit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] 14 lights! The present invention relates to a drive circuit for an ink-on-demand inkjet head, and more particularly, to a drive circuit for reducing residual vibrations in a vibration hill 1 in an ink-on-demand inkjet head.

Disaster rice sandwich! FIG. 4 is a diagram showing an example of a conventional ink-on-demand head. In the figure, 1 is a nozzle, 2 is an ink pressurized liquid chamber, 3 is an electrostrictive vibration unit, 4 is a head base, and 5 is an ink supply connection. Pipe 6 is the head drive circuit, as is well known,
The head drive circuit 6 drives the ink pressurized liquid chamber 2 of the head.
The electrostrictive vibration unit 3 consisting of an electromechanical transducer closely connected to the flexible wall of the ink is distorted, thereby reducing the volume of the ink pressurized liquid chamber 2 and ejecting ink droplets from the nozzle 1. (Refer to Japanese Patent Publication No. 53-12138).

FIG. 5(a) is a diagram showing an example of a drive signal generated by the head drive circuit 6. Normally, a pulse wave is used as an electric signal for driving the head as shown in FIG. Even if the vibration disappears, the electromechanical transducer 3 still vibrates as shown in FIG. 5(b), which has an adverse effect on the response frequency.

FIG. 6 is a diagram showing an example of an inkjet drive circuit designed to reduce the residual vibration as described above (see Japanese Patent Laid-Open No. 52-64230). In FIG. 1, 11 to 13 are mono-multivibrators, and 14 is a Resistors, 1.5 and 1.6 are transistors, 17 is an electrostrictive vibrator unit, and as shown in FIG. is applied to the electromechanical transducer 17, thereby reducing the residual vibration of the electromechanical transducer 17. Therefore, the pulse voltage required to reduce unnecessary vibrations (residual vibrations) of the electromechanical transducer is lower than the pulse voltage for ejecting ink droplets, and its value generally differs depending on each head. However, the drive circuit does not have a configuration that allows arbitrary adjustment of the second pulse voltage, which is extremely inconvenient in practice.6.Objective The present invention has been made in view of the above-mentioned circumstances. in,
In particular, this has been done with the aim of reducing the residual vibration of the vibration unit in an ink-on-demand inkjet head and improving the responsiveness of the ink ejection frequency of the head.

1. In order to achieve the above object, the present invention includes a vibrating knee knit drive circuit that generates a main pulse and a sub pulse, and distorts the flexible wall of the ink pressurizing liquid chamber with a vibrating unit to generate the above-mentioned knee knit drive circuit. An ink-on-demand inkjet head that ejects ink droplets by reducing the volume of an ink pressurized liquid chamber, characterized in that the voltage of the secondary pulse can be adjusted independently of the voltage of the main pulse. It is. below,
The invention will be specifically explained based on embodiments.

FIG. 1 is a diagram showing an embodiment of the drive circuit according to the present invention, and in the figure, 21 to 23 are mono multivibrators (hereinafter referred to as
Monomulti), 24 is Noah Gate.

25 is a resistor, 26.27 is a variable resistor, 28 to 31 are transistors, 32. ．． 33 is a resistor, 34 is an electrostrictive vibrator unit, and when a signal for driving the head is input to the monomulti 21, the monomulti 21 generates a pulse P having tw 1 in a predetermined pulse.

is generated and inputted to the other input terminal of the monomulti 22 and the NOR gate 24. The monomulti 22 is triggered by the falling edge of the output pulse of the monomulti 21, and generates a pulse P2 having a time interval between τd (pulse P) and pulse P2 during a predetermined pulse, and 23. The monomulti 23 is triggered on the falling edge of the pulse P, and the pulse P with t% 12 in a given pulse
3 is generated and inputted to one input terminal of the NOR gate 24 and simultaneously inputted to the base of the transistor 30. The transistor 30 is "ON I" while the pulse P3 is generated.
The positive state is reached, and the resistance value RIO between the intermediate terminal and the ground terminal of the variable resistor 27 is short-circuited and becomes almost zero. On the other hand, the NOR gate 24 is in the II L state when the pulse P1+"P3" is input, and at this time, the transistor 28 to which the output of the NOR gate 24 is input is "II L" state.
OFF" state, that is, the II H77 state. As a result, a high voltage +HV is applied to the base of the transistor 29 through the resistor 25, and the transistor 29 becomes OFF.
N'' state and a voltage of approximately +HV is generated on the emitter side during the generation period of pulses P1+P3.The base of the transistor 31 is connected to the intermediate terminal of the variable resistor 26.Now, the variable resistor If the resistance value between the intermediate terminal of the device 26 and the transistor 29 side is R4, the resistance value between the intermediate terminal and the variable resistor 27 side is R3, and the total resistance value of the variable resistor 27 is R, then the base voltage of the transistor 31 is On the 7th, while pulse P1 is occurring.

Also, since the transistor 30 is in the 'ON' state while the pulse P3 is being generated, the following equation is obtained.

Here, the base voltage vF3 of the transistor in the former state is
v day! , the latter one is designated as VB2.

Therefore, at the emitter of transistor 31,
When the pulse P1 is generated, a voltage of approximately VBl is generated, and when the pulse P3 is generated, a voltage of approximately VB2 is generated. Therefore, the electrostrictive vibration unit 34 uses the capacitance of the electrostrictive vibration unit to
As shown in FIG.

R= will be added. However, the resistance values of the resistors 32 and 33 are respectively R5t Re.

From the above explanation, Vρ, , v'p2 are variable resistor 2
6L: Therefore, it is obvious that they can be adjusted at the same time, and that VF6 can be adjusted independently by the variable resistor 27. In addition, VPt and VF6 are the pulses Fly"J less P3
Needless to say, it is necessary to respond to

FIG. 3 is an electric circuit diagram showing another embodiment of the present invention. This circuit is for driving a multi-head. Therefore, the area within the broken line is a circuit provided for each head, and each circuit is provided for each head. They have the same configuration ν). Therefore, in this embodiment, the L'-power supply voltage is adjusted when pulse P3 is generated, and by doing so, the slave pulse voltage value for reducing residual vibration in the multi-head drive circuit can be adjusted. It can be easily done with fewer parts. Note that the operation can be explained in the same manner as in the embodiment shown in FIG. 1, so a description thereof will be omitted.

Effects As is clear from the above explanation, according to the present invention, the main pulse Vp1 and the sub-pulse Vp1 applied to the electrostrictive vibration unit
P2 can be adjusted to any voltage value.

Moreover, the slave pulse VP2 can be adjusted to a different value from the main pulse vpt, and the slave pulse VP2 and the main pulse VPt can be adjusted to a different value.
The time interval can also be adjusted arbitrarily. Therefore, the secondary pulse can be set so as to cancel the residual vibration of the electrostrictive vibration unit caused by the main pulse for ejecting ink droplets.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing an embodiment of a drive circuit according to the present invention;
2 is a diagram showing an example of a drive pulse generated by the circuit of FIG. 1, FIG. 3 is a diagram showing another embodiment of the drive circuit according to the present invention, and FIG. 4 is a diagram showing a conventional on-demand FIG. 5 is a diagram showing an example of an inkjet head, and FIG. 5 is a waveform diagram showing a conventional head drive signal and a vibration state of a vibration unit.
FIG. 6 is a diagram showing an example of a conventional head drive circuit, and FIG.
The diagram is. FIG. 3 is a diagram showing an example of a conventional head drive signal. 21-23... Mono multivibrator, 24...
NOR gate, 25...Resistor, 26.27...Variable resistor, 28-31...Transistor, 32.33.
...Resistor, 34...Electrostrictive vibration unit. Figure 1 Figure 2 Condolence 3 Death Figure 4

Claims (1)

[Claims] A vibration unit drive circuit that generates a main pulse and a sub-pulse is provided, and the flexible wall of the ink pressurized liquid chamber is distorted by the vibration unit to reduce the volume of the ink pressurized liquid chamber and eject ink droplets. 1. A drive circuit for an ink-on-demand ink-jet head, characterized in that the voltage of the secondary pulse can be adjusted independently of the voltage of the main pulse.