JPH0516354A - Ink jet print head and electronic apparatus provided therewith - Google Patents

Abstract

PURPOSE:To provide an inexpensive ink jet print head realizing high density, high quality printing and an electronic apparatus employing the print head. CONSTITUTION:Long grooves 11, 11' are formed, in array, with predetermined intervals in an electrostrictive element 1 and electrodes 13, 13' are provided in the long grooves 11, 11' while extending along the walls thereof so that discrete ink channels are constituted by every other long grooves 11, and a nozzle plate 2 having nozzles 21 communicated with discrete ink channels (long grooves 11) is fixed to the surface of the electrostrictive element 1 on the long groove side thereof. When a voltage is applied on the long groove 11 of the discrete ink channel and respective electrodes 13, 13' of adjacent long groove 11', th2 electrostrictive element 1 displaces at a part relevant to the discrete ink channel because of the polarization charges and the polarity of the voltage and thereby the volume of ink in the long groove 11 varies.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel ink jet print head for ejecting ink by utilizing a change in ink volume due to displacement of an electrostrictive element, and a new ink jet print head provided therewith
The present invention relates to electronic devices such as printers, word processors, facsimiles, and plotters.

[0002]

2. Description of the Related Art One of ink jet print heads uses an electrostrictive element. In this print head, an electrostrictive element is generally attached to a part of an individual ink path branched from a common ink path, an electric field is applied to the electrostrictive element to displace the electrostrictive element, and the ink volume of the individual ink path is reduced. By changing the ink, the ink in the individual ink passage is pushed out from the tip end port of the individual ink passage. Further, the head itself is tilted with respect to the scanning direction to increase the density and quality of print dots.

[0003]

However, in the printing mechanism adopted in the general ink jet print head including the print head as described above, the density of printing dots and the quality of printing are improved more than ever. Is structurally difficult. For example, in the Kaiser method, it is difficult to increase the printing density any more, and in the bubble jet method, bubbles due to heat are used, so the degree of freedom in ink selection is low when the bubble generation conditions and charring are taken into consideration, and printing quality is reduced. Is limited.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide an inexpensive ink jet print head which realizes high density and high quality printing, and an electronic device equipped with this print head.

[0005]

In order to achieve the above-mentioned object, the ink jet print head of the present invention has long grooves formed in an electrostrictive element body at regular intervals in an array shape, and each long groove is formed in each of the long grooves. An electrode extending along the wall of the groove is provided to form one individual ink path by every other long groove, and a long ink groove is formed on the surface of the electrostrictive element body on the long groove forming side. A nozzle plate having a nozzle communicating with the groove is attached.

In the print head of the present invention, among the long grooves arranged in an array, in the individual ink path constituted by every other long groove, the portion of the electrostrictive element body related to this individual ink path is formed. Introduces a new printing mechanism that changes the ink volume of the long groove by displacing it in the array direction and the direction perpendicular to the array direction and the extending direction of the long groove, and pushes out the ink of the long groove that becomes individual ink paths. It is a thing. This printing mechanism will be described in detail. The portion of the electrostrictive element body related to the individual ink path is polarized in the array direction, for example, and in this polarized state, the long groove that becomes the individual ink path and the adjacent long groove When a voltage having an appropriate polarity is applied to the electrodes provided in, the portion of the electrostrictive element body related to the individual ink paths is displaced in the direction perpendicular to the array direction according to the positive / negative charge of polarization and the positive / negative polarity of the voltage, The ink volume of the long groove that serves as an individual ink path changes.

That is, for example, two portions of an electrostrictive element body formed by a long groove serving as an individual ink path and a long groove on both sides of the long groove (hereinafter, this portion is simply referred to as a partition) In the above description), the side away from the middle long groove (individual ink path) is polarized positively and the individual ink path side is negatively charged. In this polarization state, an electrode provided in the middle long groove When a positive voltage is applied to the electrodes and a negative voltage is applied to the electrodes provided in the long grooves on both sides, both partition walls expand in the array direction and contract in the direction perpendicular to the array direction and the extending direction of the long grooves. To do. As a result of the deformation of both partition walls, the ink volume in the middle long groove is reduced, the ink in the long groove is pushed, and the ink is ejected from the corresponding nozzle of the nozzle plate mounted on the electrostrictive element body. To be done. As described above, in the print head of the present invention, the portion of the electrostrictive element body related to the individual ink path is displaced (expanded and contracted) to change the ink volume of the long groove that becomes the individual ink path, thereby changing the individual ink path. Has the effect of pushing out the ink.

In the print head of the present invention, a known electrostrictive element body may be used, for example, P
The one made of ZT is used. Although the electrostrictive element body is polarized in an arbitrary direction (for example, the array direction), this polarization may be performed in the step of providing an electrode in the long groove of the electrostrictive element body, or from the beginning. A polarized electrostrictive element body may be used.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The ink jet print head of the present invention and electronic equipment having the same will be described below based on embodiments. FIG. 1 is an exploded perspective view of an embodiment of a print head mounted on an electronic device such as a printer or word processor. The structure of the electronic device other than the print head is not different from usual, and the print head will be mainly described here. The print head shown in FIG. 1 includes an electrostrictive element body 1, a nozzle plate 2 attached to the surface of the electrostrictive element body 1, and a lid 3 attached to one side end surface of the electrostrictive element body 1.

In FIG. 1 and FIG. 2 showing the cross section of the main part thereof, the electrostrictive element body 1 is provided with an array of a plurality of (seven in this embodiment) long grooves 11 arranged at regular intervals by processing such as dicing. It is formed into a shape. The elongated groove 11 longitudinally cuts the electrostrictive element body 1 from the vicinity of one side (lower side) of the electrostrictive element body 1 to the other side (upper side) and opens at the side end surface of the other side (see FIG. 1). A plurality of (six in this embodiment) long partition walls 12 are formed between the long grooves 11 by the long grooves 11, and the long grooves 11 and the partition walls 12 have a rectangular plane and cross section.

As shown in detail in FIG. 2, the elongated grooves arranged in an array are composed of wide elongated grooves 11 and slightly narrower elongated grooves 11 '. 11 is an individual ink path, and the wide long groove 11 is a narrow long groove 1.
It alternates with 1 '. Therefore, the individual ink passages are composed of every other long groove 11. However, for the sake of convenience, the electrostrictive element body 1 shown in FIG. 1 does not show a difference in width between the long grooves 11 and 11 ′, and in FIG.
1'is located at both ends of the array-like array, and there are wide elongated grooves 11 every other one from the array, and the number of the elongated grooves 11 is three in total. Further, electrodes 13 and 13 'extending along both side walls and a bottom wall of the long groove 11 and 11' are provided in the long grooves 11 and 11 ', respectively, and the electrodes 13 and 13' are opened in the long grooves 11 and 11 '. Do not extend from one end to almost the center. Furthermore,
The partition walls 12, 12 between the wide elongated groove 11 and the adjacent narrow elongated grooves 11 'are polarized in the arrow direction (array direction) of FIG. 2, respectively.

The nozzle plate 2 attached to the surface of the electrostrictive element body 1 on the side where the long groove is formed has the number (three) of nozzles 21 corresponding to the individual ink passages. In FIG. 2, each nozzle 21 is a fine hole penetrating the plate 2 and communicates with the wide elongated groove 11. Further, the nozzle plate 2 is overlapped with the upper portion of the electrostrictive element body 1 as shown by the one-dot chain line in FIG. 1, and the long grooves 11 and 1 provided with the electrodes 13 and 13 ′ are provided.
A part of 1'is not covered with the nozzle plate 2. However, an appropriate holding plate (not shown) or the like is attached to this portion to prevent ink from leaking.

The lid 3 closes all the long grooves 11 and 11 'which are opened on the upper end surface of the electrostrictive element body 1 so that ink does not leak from the openings of the individual ink passages. Further, each long groove 11 which is an individual ink path communicates with an ink supply path (not shown) provided at an appropriate position of the electrostrictive element body 1 inside the electrostrictive element body 1. Therefore, the ink flows into each long groove 11 through the ink supply path and is ejected from the nozzle 21 corresponding to the long groove 11.

As is apparent from FIG. 1, the print head has a so-called vertical length whose vertical dimension is larger than the depth dimension of the head. Incidentally, to give an example of the dimensions of the main part, the width of the partition wall 12 between the long grooves 11 and 11 ′ is 50 μm.
m, the width of the long groove 11 is 33 μm, the longitudinal dimension (length) of the long groove 11, 11 ′ is 10000 μm, the long groove 11, 11 ′
Has a depth of 500 μm.

Next, the operation of the print head thus constructed will be described. In FIG. 3 showing an enlarged cross-sectional view of the main part, as shown in FIG. 2, a wide elongated groove 11 and a narrow elongated groove 1 are provided.
In the state where the partition walls 12a and 12b between 1a and 11b are polarized in the array direction to the left and to the right, respectively, the long groove 1
A positive voltage is applied to the electrode 13 of No. 1 and the long grooves 11a and 11b.
A negative voltage is applied to each of the electrodes 13a and 13b. By applying the voltage of this polarity, the partition walls 12a, 12b
Is the relationship between the positive charge of polarization and the negative polarity of the voltage of the electrodes 13a and 13b on the side away from the long groove 11, respectively, and the negative charge of polarization and the positive polarity of the voltage of the electrode 13 on the long groove 11 side. From the relationship with the above, at the same time as extending in the array direction, it shrinks in the direction perpendicular to the array direction and the extending direction of the long groove (vertical direction in the figure). As a result, the partition walls 12a and 12b and the part of the nozzle plate 2 pulled along with the displacement of the partition walls substantially reduce the ink volume of the long groove 11 as shown in FIG. It is pushed and ejected from the corresponding nozzle 21 of the nozzle plate 2.

After the ink is ejected, the applied voltage is cut off, or
Alternatively, when the polarity of the applied voltage is reversed, the partition walls 12a and 12b return to the original state when the voltage is cut off. In the case of the voltage polarity reversal, the partition walls 12a and 12b have an action opposite to the above action. That is, the partition walls 12 a and 12 b are provided with the positive charge of polarization and the electrode 13 on the side away from the long groove 11.
Due to the positive polarity of the voltages of a and 13b, and the negative charge of the polarization on the side of the long groove 11 and the negative polarity of the voltage of the electrode 13, they contract in the array direction and extend in the vertical direction.
In either case, the partition walls 12a and 12b return to their original state, and the ink volume of the elongated groove 11 is restored.

In the above-described embodiment, the partition walls 12a and 12b are deformed to reduce the ink volume in the long groove 11 to push out the ink, but the reaction of the partition walls 12a and 12b to the original state is utilized. May be. That is, first, the partition wall 12a,
12b is contracted in the array direction and expanded in the vertical direction to increase the ink volume of the long groove 11, and the long groove 11 is filled with ink. Then, the partition wall 12a,
12b may be returned to the original state, the volume of the long groove 11 may be reduced, and the ink may be pushed out at the same time.

Further, in the above embodiment, when the polarization directions of the partition walls 12a and 12b are opposite, the elongated grooves 11 and 11 are formed.
Similar effects can be obtained by changing the polarities of the voltages applied to the electrodes 13, 13a, 13b of a and 11b. When the ink in the long groove 11 is not ejected, if the high impedance is applied to the electrodes 13, 13a, 13b, the partition walls 12a, 12b will not be deformed, and, of course, the ink will not be ejected through the nozzle 21.

[0019]

Since the ink jet print head of the present invention is constructed as described above, by applying a voltage of an appropriate polarity to the electrodes provided in the long groove, electrostriction of the individual ink paths can be achieved. Depending on the positive and negative charges of polarization and the positive and negative polarities of the applied voltage in the part of the element body, the part of the electrostrictive element body is displaced in the array direction and in the direction perpendicular to the array direction and the extending direction of the long groove. The epoch that the ink volume of the individual ink passage (long groove) is changed (increased or decreased) as a result of the deformation of the portion of the electrostrictive element body, and the ink of the individual ink passage whose volume has decreased is pushed out. It is a target.

Therefore, the print head of the present invention can easily realize high density and high quality printing. Further, since the mass production can be performed by using the existing technology and manufacturing process, the productivity is very high and the price is low. As a result, even in an electronic device equipped with the above print head, effects such as high quality printing and improvement of printing performance can be obtained.

[Brief description of drawings]

FIG. 1 is an exploded perspective view of an embodiment of a print head according to the present invention.

FIG. 2 is an enlarged cross-sectional view of a main part of the print head shown in FIG.

FIG. 3 is an enlarged sectional view of an essential part for explaining the operation of the print head shown in FIG.

[Explanation of symbols]

1 Electrostrictive element body 2 nozzle plate 11, 11 'Long groove 12 partitions 13, 13 'electrode 21 nozzles

Claims (2)

[Claims] 1. An electrostrictive element body is formed with long grooves in an array at regular intervals, and an electrode extending along the wall of the groove is provided in each long groove, and every other long groove is formed. An ink jet print head comprising a single individual ink passage, and a nozzle plate having nozzles communicating with the long groove serving as the individual ink passage is attached to the surface of the electrostrictive element body on the long groove forming side. . 2. An electronic apparatus comprising the ink jet print head according to claim 1.