JPS602372A - Liquid jet head device - Google Patents

Abstract

PURPOSE:To widen the variable range of the dot diameter of recording liquid droplets by a method in which plural electrical and mechanical conversion means are provided to a liquid jet head device, meniscus of recording liquid is controlled by a part of the means, and the recording liquid is discharged by the rest of the means. CONSTITUTION:According to input tonal signals 21, voltage V0 and V1 to be applied to piezo-electric elements 11 and 12 are set up by DA converters 22 and 24 and amplifiers 23 and 25, and pulse signals for driving a piezo-electric element 12 for controlling meniscus are sent out from a mono-stable multi vibrator 33 by input trigger signals 32. When the signal 21 is greater than intermediate value, signal phi2 is output from a multiplexer 36 but when it is smaller, signal phi3 is output. By the signal phi2, voltage pulse in the direction of polarization is applied to the piezo-electric element 12 through switching elements 28 and 29, and also by the signal phi3, voltage pulse in the opposite direction is applied to control the meniscus. Signal phi1 is sent out from monostable multi vibrator 35 through a delay circuit 34, and recording liquid droplets are sent out by the piezo-electric element 11 for discharging. The amount of recording liquid to be discharged, or the dot diameter of recording liquid droplets, can be widened with respect to variable ranges.

Description

TECHNICAL FIELD The present invention relates to a liquid ejecting head device, and a liquid ejecting head device in a recording apparatus that ejects recording droplets according to information input to the ejecting head. The object of the present invention is to provide a means for widening the variable range of the amount of recording liquid ejected from the recording liquid.

Prior Art In conventional on-demand type liquid jet recording devices, one electric/mechanical conversion means is provided for one jet head, and meniscus control and recording liquid ejection control are performed by the same electric/mechanical device. This is done by a conversion means. Therefore, there are five drawbacks in that the variable range of the amount of the ejected recording liquid controlled by the electrical signal applied to the electromechanical converter means is narrow (and, by extension, the variable range of the dot diameter of the recording liquid droplet is narrow).

OBJECTS OF THE INVENTION Accordingly, it is an object of the present invention to provide a liquid ejecting head device which eliminates the above-mentioned drawbacks of conventional liquid ejecting head devices and allows a wide variable range of the dot diameter of ejected recording droplets.

Structure of the Invention The present invention comprises a plurality of electromechanical conversion means (in a specific example described later, for example, piezoelectric elements 11 and 12 in FIG. 1) and: a part of the plurality of electromechanical conversion means. ) a means for controlling the meniscus (also a means for controlling the meniscus by the piezoelectric element 12); a means for ejecting the recording liquid by the remaining of the plurality of electromechanical transducers (also a means for controlling the meniscus by the piezoelectric element 12); 11, a liquid ejecting head device comprising: a means for ejecting a recording liquid; and;

In the above, the citation of the specific examples described later does not limit the scope of the present invention in any way, and the embodiments of the present invention can be modified as appropriate within the scope of the claims.

Furthermore, in this specification, the term "electrical-mechanical conversion means" refers to a means for mutually converting an electric signal and a mechanical displacement, such as a piezoelectric element, an electrostrictive element, or a magnetostrictive element, and is not limited to a specific embodiment thereof. do not have.

Further, when the present invention is applied to a multi-head liquid jet recording apparatus, the present invention is applied to all or part of the heads.

Hereinafter, with reference to the drawings, specific examples of the liquid jet head device of the present invention, the structure and operation of the drive device for the liquid jet head device described above, and other specific examples of the liquid jet head device of the present invention will be explained in detail in this order. . The following description will be made regarding an example in which the electric fist mechanical conversion means is a piezoelectric element.

Specific examples of the liquid jet head device of the present invention (Figs. 1 to 5)
Figure) Figure 1 shows a specific example of a liquid ejecting head device of the present invention, in which 11 is a piezoelectric element for ejecting recording liquid;
2. Light piezoelectric element, 1. Controls the movement of the meniscus.
3 is a nozzle pipe, 14 is a recording liquid (ink), and 15 is a meniscus at the tip of an orifice.

In order to eject recording droplets with a small dot diameter by the liquid ejecting head device shown in FIG. 1, two voltage pulses in opposite polarization directions are applied according to the following procedure. The timing is determined in response to the trigger pulse shown in Fig. 2(a).
Assume that a voltage with the waveform shown in b) is applied. As a result, the piezoelectric element 12 rapidly expands, and the meniscus 15 inside the nozzle tube 16 retreats as shown in FIG. 3(a) and enters the tube. Thereafter, the meniscus 15 moves forward due to surface tension (FIG. 2(b)). At the timing when the meniscus 15 has fully advanced, the piezoelectric element 11 for ejecting recording droplets is charged with a waveform shown in FIG. 2(C) in its polarization direction.
d)). The timing at which the voltage pulse shown in FIG. 2(C) is applied is the same as when the meniscus has fully advanced, so the movement due to the surface tension of the meniscus is added to the ejection of the recording liquid, so that the piezoelectric element 11 The recording liquid can be ejected even if the yield is small, and therefore droplets with a small dot diameter can be ejected.

On the other hand, in order to eject droplets with a large dot diameter, the following procedure is used. First, a voltage pulse is applied to the meniscus control piezoelectric element 12 in its polarization direction.

The timing is such that a positive voltage pulse having the waveform shown in FIG. 4(b) is applied in response to the trigger pulse shown in FIG. 4(a). At this time, the time constant of the charging circuit of the piezoelectric element 12, which will be described later, is such that the recording liquid is not immediately ejected, and as shown in FIG.
) to achieve the meniscus state shown. Next, a voltage pulse shown in FIG. 4(C) is applied to the ejection piezoelectric element 11 to cause the piezoelectric element 11 to rapidly contract, thereby ejecting the recording liquid (FIG. 5(b)).

In this case, the amount of recording liquid ejected from the tip of the orifice due to the action of the meniscus control piezoelectric element 120 is added to the amount of recording liquid ejected by the ejection piezoelectric element 11 alone, so the amount of recording liquid ejected increases. A large dot diameter can be obtained.

2, by controlling the liquid ejecting head device shown in FIG. 1 with the timing and waveform voltage shown in FIGS. 2 and 4, the variable range of the amount of recording droplets to be ejected is expanded. The variable range of the dot diameter of recording droplets is also expanded.

Configuration of the drive device for the liquid jet head device shown in Fig. 1 (
6) FIG. 6 shows a drive device for the liquid ejecting head device of FIG. A D-A converter 23.25 that converts the tone signal into an analog quantity amplifies the tone signal converted to an analog quantity and transmits it to the piezoelectric element 1.
This is an amplifier for applying 1.12. 26 and 27 are switching elements for applying voltage pulses to the ejection piezoelectric element 11, and the switching element 26 is, for example, p
Consisting of np switching transistors, same <27
is composed of, for example, an npn switching transistor,
The bases thereof are controlled by signals ψl and ψ1, respectively, which will be described later. 28 to 31 are switching elements for applying voltage pulses to the meniscus control piezoelectric element 12 in the same direction or in the opposite direction to its polarization direction, and the switching elements 28 and 30 are composed of, for example, pnp switching transistors, and the same 29.31 is pnp for example
It consists of switching transistors, and the bases of these switching transistors respectively receive signals ψ2 . ψ2. ψ3 and ψ3). Further, the output voltage Vo of the amplifier 26 is adjusted so as to be higher than the output voltage Vl of the amplifier 25. Therefore, the amount of displacement given by the ejection piezoelectric element 11 is given by the meniscus control piezoelectric element 12. It is thicker than the displacement amount.

32 is a trigger signal for controlling the recording liquid ejection operation, and 63 is a monostable multi-vibration brake driven by the trigger signal 52, the generated pulse width of which is determined by, for example, an external resistor. 34 is a delay circuit, 35 is a monostable multi-bi break, 36 is a multiplexer, and DA converter 2.
Outputs the ψ3 signal or the ψ3 signal depending on the high level of the MSB (the most significant signal among the 20 input signals) and the low level of the X-ray.

Effect of the drive device on the liquid jet head device shown in Fig. 1 (
(Fig. 2 to Fig. 6) In the driving device shown in Fig. 6, D
The voltages 0 and Vl applied to the piezoelectric elements 11 and 12 are set by the -A converters 22 and 24 and the amplifiers 23 and 25. Input 1 - A heat pulse signal is outputted from the monostable multi-bi-break 63 by the IJ signal 52 to drive the piezoelectric accumulator 12 for controlling the spacing. This pulse signal is given to the multiplexer 3B, and when the input gradation signal 21 is thicker than the intermediate value, that is, the highest dot among the inputs to the D-A converter 220 (MS)
When B is at a high level, the ψ2 signal is output, and the gradation signal 2
When 1 is smaller than the intermediate value, that is, when the most significant bit signal MS13 is at a low level, the ψ8 signal is output. Switching elements -28, 29 by the ψ2 signal
When the piezoelectric element 12 is turned on, a voltage pulse is applied in its polarization direction (FIG. 4(b)), and the meniscus behaves as shown in FIG. 5(a). On the other hand, the switching elements 30 and 31 are turned on by the ψ8 signal, and a voltage pulse is applied to the piezoelectric element 12 in the opposite direction to its polarization direction (Fig. 2(b)), and the behavior of the meniscus is as shown in Fig. 6 (al to (C)). ) as shown.

After controlling the meniscus with the ψ2 signal or the ψ3 signal, a delay pulse is output from the delay circuit 64, which is input to the monostable multivibrator 65 to form the ψl signal. Note that the delay time of the delay circuit 54 is adapted to the timing from when the meniscus is in the retracted state shown in FIG. 3(a) to when it is fully advanced to the tip of the orifice.

The switching element 26 is turned on by the ψ1 signal, and a positive voltage pulse is applied to the ejection piezoelectric element 11 (FIGS. 2 and 4), which is discharged and returns to the standby state.
t'' and ψB multiplied signals are discharged by the circuit including transistor 61 or 29, respectively, upon termination of the φ3 signal.

As described above, according to the apparatus shown in FIG. 6, the discharge piezoelectric element 1
1 and the meniscus control piezoelectric element 12 can be easily driven. Although an example has been described in which the meniscus control piezoelectric element 12 is switched and controlled, a plurality of ejection piezoelectric elements with different electrical/mechanical conversion characteristics are provided, and these are switched and controlled according to the size of the dot diameter. You can also do that.

Other specific examples (seventh example) of the liquid jet head driving device of the present invention
Figure) In the above-mentioned device, by making the voltage pulse value VO applied to the ejection piezoelectric element 11 larger than the voltage pulse value Y14 applied to the meniscus control piezoelectric element 12, the amount of displacement caused by these piezoelectric elements can be made different. However, as another specific example of the present invention, as shown in FIG. It is also possible to vary the amount of displacement.

Furthermore, an example has been described in which there is one piezoelectric element 11 or 11a for discharge and one piezoelectric element 12 or 12a for meniscus control, but it is clear that the same effect can be achieved even if a plurality of one or both of them is provided. .

Effects of the Invention As described in detail above, according to the present invention, a plurality of electrical-to-mechanical conversion means are provided in a liquid jet head device, a part of them controls the meniscus, and the remaining part controls the recording liquid. As a result, it is possible to widen the variable range of the amount of the discharged recording liquid and, in turn, the variable range of the dot diameter of the recording liquid droplet, compared to the conventional apparatus.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a main part of a specific example of a liquid ejecting head device according to the present invention, and FIGS. FIG. 6(a) is an explanatory diagram of operation timing for ejecting droplets. Φ), (C), and (d) are explanatory diagrams showing the movement of the meniscus and the state of recording droplet ejection when the apparatus of FIG. 1 is used to eject recording droplets with a small dot diameter. 4 (a), (b) j (C) is an explanatory diagram of the operation timing for causing the apparatus of FIG. 1 to eject a recording droplet with a large dot diameter, and FIG. 5 (a), ( b) is an explanatory diagram showing the movement of the meniscus and the state of ejecting four drops of recording liquid when the apparatus of FIG. FIG. 7 is a block diagram showing a part of the driving device for the liquid ejecting head device in a circuit diagram, and a sectional view of a main part of another specific example of the liquid ejecting head device of the present invention. In the figure, 11 is a piezoelectric element which is an electrical/mechanical conversion means for discharging;
12 is a piezoelectric element which is an electrical/mechanical conversion means for meniscus control; 13 is a nozzle tube; 14 is a recording liquid; 15 is a meniscus at the tip of the orifice; 26 to 31 are switching elements; ψ1. ψl, ψ! . ψB indicates a control signal for the switching element. 4 active items

Claims (1)

[Scope of Claims] (1) A plurality of electrical/mechanical converting means, means for controlling the υ meniscus by some of the plurality of electrical/mechanical converting means, and a plurality of electrical/mechanical converting means. A liquid ejecting head device comprising: means for ejecting recording liquid from the remaining portion of the head; (21) Claim (1), wherein the amount of displacement by the electro-mechanical conversion means for ejecting the recording liquid is set larger than the amount of displacement by the electro-mechanical conversion means for controlling the meniscus. Liquid ejecting head device. (3) Either the electro-mechanical conversion means for ejecting the recording liquid or the electro-mechanical conversion means for controlling the meniscus is switched depending on the size of the recording liquid droplet. A liquid ejecting head device according to claim (1) that is controlled.