JPH02165957A - Printer head - Google Patents

Abstract

PURPOSE:To control the size of an ink particle and to obtain a beautiful character.graphic by providing an electrostrictive element for driving and detecting at a vibrator to be self-vibrated, and intermittently continuing the vibration of the vibrator. CONSTITUTION:Driving means 9 having a self-exciter corresponding to the number of vibrators 4 intermittently vibrate the vibrators 4 according to print data from a print data input terminal 17. In this case, an induced voltage regarding the deviation of the vibrator 4 of an electrostrictive element 6 is inverted to be amplified by a transistor 14 and a load resistor 13, and applied to an electrostrictive element 5. Thus, the electrostrictive element 5 is further elongated or contracted to increase the deviation of the vibrator 4. Soon, it is balanced with the input energy so that the end amplitude of the vibrator becomes constant. The positional energy of the vibrator 4 is varied to kinetic energy to press ink 10 toward a nozzle 2a, a wavy face of small uneven parts is generated in a boundary of the ink 10 at the nozzle 2a to separate ink particles uniformly having relatively small particles. Accordingly, when the vibrating time of the vibrator 4 is controlled, flying ink amount can be controlled.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to the structure of a head for a printer which forms characters and figures by disposing a vibrator in ink and ejecting ink from a nozzle by intermittent vibration.

[Conventional technology]

FIG. 1 is a side sectional view of a printer head according to the present invention, and the prior art will be explained with this drawing. Reference numerals 1, 2 and 3 indicate a nozzle plate and a housing in which one or more nozzles holding ink 10 represented by a dotted pattern are arranged in a direction perpendicular to the plane of the paper.

Reference numeral 4 denotes a vibrator made of an elastic body, to which electrostrictive elements 5 and 6 are fixed. Cables 7 and 8 lead out the electrodes 5a and 5b of the electrostrictive elements 5 and 6, and are made of insulating sheets 7a and 8a and a conductor 7.
It consists of b and 8b.

The vibrator 4 is strongly supported by the housings 1 and 3. In the conventional technique, when a voltage is applied to the cable 7 using only the electrostrictive element 5, when the electrostrictive element stretches, it is suddenly bent toward the nozzle 2a, and this pressing force causes the ink droplets 11 to be ejected from the nozzle 2a. On the contrary, a voltage is normally applied to contract the electrostrictive element 6 and bend the vibrator 4 in the opposite direction to the nozzle 2a.

Here, when the voltage application is interrupted, the potential energy of the vibrator 4 changes to kinetic energy and presses the cylinder 10 in the direction of the nozzle 2a. A larger pressing force than the above is obtained to eject large ink droplets 11.

In this manner, in the prior art, the ink droplets 11 are ejected by the single pressing force of the vibrator 4.

[Problem to be solved by the invention]

However, in the conventional technology described above, ink droplets are ejected by the single pressing force of the vibrator, which results in large variations in the size of the ink droplets, resulting in variations in the shading of characters and figures in the printout results, noise-like blurring, etc. There was a problem that occurred.

Therefore, the present invention is intended to solve these problems, and its purpose is to provide a vibrator with an electrostrictive element for driving and detection, so that it can self-excite vibration, and by intermittent vibration of the vibrator, ink droplets can be reduced. To provide a printer head that can control the size of characters and produce beautiful characters and figures.

[Means to solve the problem]

The printer head of the present invention includes a nozzle plate having a single or plural number of nozzles, a housing for holding the nozzle plate and ink, and a vibrator corresponding to the number of nozzles on the nozzle plate. are arranged substantially parallel to the nozzle plate. The vibrator includes an elastic body which is also a common electrode, and first and second electrostrictive elements having electrodes on both sides of the elastic body facing the nozzle of the nozzle plate. A positive feedback loop is formed between these first and second electrostrictive elements to cause the vibrator to self-oscillate.

A feature of the present invention is that the self-excited vibration of the vibrator is intermittently controlled to eject ink droplets.

[Effect]

According to the above configuration of the present invention, by causing the vibrator to self-oscillate, multiple pressing forces are generated within the conventional single-shot time. In this way, uneven waves are generated multiple times on the ink surface outside the nozzle. When moving from convex to concave, the ink breaks and flies away. Conventionally, this unevenness is large in one shot, so the size of the ink droplet is different each time due to complex effects such as the affinity between the nozzle and the ink and the viscosity of the ink, resulting in variations in the size of the printed dots formed. become.

However, in the present invention, since small ink droplets are ejected multiple times, the size or shading of the printed dots can be accurately controlled.

〔Example〕

FIG. 1 is a diagram showing a side sectional view of an embodiment of the present invention,
I mentioned some of them earlier. Next, add an explanation.

Reference numeral 9 denotes a driving means having a self-oscillation circuit corresponding to the number of vibrators 4.

The driving means 9 makes the vibration of the vibrator 4 intermittent according to the print data from the print data input terminal 17. Drive means 9
is the common electrode of each vibrator 4, and the cables 7 and 8 connect the electrostrictive elements 5 and 6. Do it in 4a.

A specific example corresponding to one nozzle including details of the driving means 9 will be explained with reference to FIG.

In FIG. 2, electrostrictive elements 5 and 6 are used for driving and for detecting the displacement of vibrator 4, respectively.

Here, the reason why the electrostrictive element 6 is made shorter than 5 in FIG. 1 is to prevent the amount of deflection of the tip of the vibrator 4 from becoming smaller due to increased rigidity due to the electrostrictive element 6. Furthermore, since the portion shown in the figure is subjected to a large displacement stress for detection, the detection electromotive voltage is not necessarily small.

Now, the electromotive voltage related to the displacement of the vibrator 4 of the electrostrictive element 6 is inverted and amplified by the transistor 14 and the load resistor 13 and applied to the electrostrictive element 5. As a result, the electrostrictive element 5 expands or contracts more and more, and the displacement of the vibrator 4 increases. Eventually, the input energy is balanced and the tip amplitude of the vibrator becomes constant. The direction of vibration is indicated by double-headed arrows in FIGS. 1 and 2.

The resistor 12 is a bias resistor that starts oscillation immediately when the transistor 15 becomes conductive. 15a is transistor 1
5 representing the control electrode terminal or print data input terminal,
16 is a power supply, which is about 50V to 200V.

FIG. 3 shows an example of the operation shown in FIG. 2.

(a) is an example of a print data signal applied to the control electrode terminal 15a of the transistor 15.

(b) shows the amplitude near the tip of the vibrator 4.

Although FIG. 3(a) corresponds to the conventional one-shot pressing force generation, the present invention is characterized by generating multiple pressing forces.

The maximum value of the pressing force of this multiple shots is smaller than the conventional single shot,
Therefore, a small uneven wave surface is generated at the interface of the ink 10 at the nozzle 2a of the nozzle plate 2, and relatively small uniform ink droplets are separated. Therefore, by controlling the vibration time of the vibrator 4, the amount of flying ink can be controlled.

As a result, the variation in printed dots is reduced,
You can get beautiful printed characters and figures. Furthermore, since the amount of ink can be controlled, images with gradation can also be printed out.

〔Effect of the invention〕

According to the present invention described above, by making the vibrator disposed in the ink have a self-oscillating configuration, the ink m from the nozzle can be controlled, and the effect of printing out beautiful characters, figures, and images is extremely large.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view of a printer head according to the present invention. FIG. 2 is a diagram showing a specific example of the driving means 9 shown in FIG. 1. FIG. 3 is a diagram showing an example of the operation shown in FIG. 2. FIG. 3(a) is a diagram showing a waveform related to the print data that determines the self-oscillation time width of the vibrator 4, and FIG. 4 is a diagram showing the vibration amplitude near the tip of the child 4 corresponding to FIG. 3(a). FIG. Applicant Seiko Epson Co., Ltd. Agent Patent attorney Kizobe Suzuki and 1 other person2, Nozzle plate 2nd cause→■ (Q) Hishi! 1 station Figure 3

Claims (1)

[Claims] (1) In a printer head consisting of a nozzle plate having one or more nozzles, a housing for holding the nozzle plate and ink, and a vibrator corresponding to the number of nozzles on the nozzle plate, the vibrator is attached to the nozzle plate. an elastic body disposed substantially parallel to the nozzle plate and serving as a common electrode, and first and second electrostrictive elements having electrodes on both sides of the elastic body facing the nozzle of the nozzle plate. 1. A printer head characterized in that a positive feedback loop is formed between the first and second electrostrictive elements, and the ejection of the ink from the nozzles of the nozzle plate is controlled by intermittent vibration of the vibrator.