JP2001010039A - Ink jet printer head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent a nozzle plate 7 joined to a partition wall from being deformed, and prevent characters and images from being unable to be correctly printed due to a deviation of hit positions of ink drops onto recording media, bleeding of ink drops or the like in an ink jet printer head which bends and shifts the partition constituting an ink channel and formed of piezoelectric ceramics, thereby pressurizing ink and discharging ink drops. SOLUTION: In mounting a nozzle plate 7 to the side of one end of a channel member 3 which has an electrode for driving set in a side face and consists of partition walls 1 of piezoelectric ceramics polarized in a heightwise direction and arranged side by side, only a part of the partition walls 1 near the nozzle plate is not polarized, or a member of a piezoelectric ceramics not polarized or of an insulating ceramics such as alumina, zirconia or the like, or glass is joined by bonding or the like manner to the side of the nozzle plate 7 of the partition walls 1.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet printer head mounted on an ink jet printer used for printing characters, images and the like.

[0002]

2. Description of the Related Art In recent years, inkjet printers have been widely used as printers for printing information such as colorized images and characters at a low running cost.

As an ink jet printer head (hereinafter referred to as a head) mounted on this ink jet type printer, a heater is provided in a flow path filled with ink, and the ink is heated and boiled by the heater to generate bubbles. The thermal jet method, in which pressure is applied to generate ink droplets from the ink discharge holes, and the partition walls that form the flow path filled with ink are bent or displaced directly or indirectly by piezoelectric elements, and mechanically. In general, a piezoelectric system in which ink in a flow path is pressurized and ink droplets are ejected from an ink ejection hole is used.In particular, a piezoelectric system has excellent durability and responsiveness, and does not directly heat ink.
There is an advantage that the type of ink is not limited.

As shown in FIG. 4, a piezoelectric type head has a plurality of partition walls 21 arranged side by side.
A flow path member 23 made of piezoelectric ceramics, which forms an ink flow path 22, is bonded to the top surface of each partition wall 21 by adhesion so as to cover each flow path 22, and ink is introduced into each flow path 22. Plate 25 having an ink supply hole 24 for ink jetting, and one end of the flow path member 23 are bonded together with a partition 21 so as to cover each flow path 22, and ink discharge communicating with each flow path 22 There was a nozzle plate 27 provided with a hole 26, and a drive electrode 28 was formed on both sides of each partition wall 1 along the longitudinal direction from the joint with the nozzle plate 27.
In addition, the other end side of the flow path member 23 has a closed structure, and reference numeral 29 denotes a lead wire of the driving electrode 28.

In order to discharge ink droplets using the head 30, a voltage is applied to driving electrodes 28 formed on both side surfaces of the partition 21. FIG.
As described in (a) and (b), the driving principle is described, for example, by driving electrodes 28b and 28c and driving electrodes 28h and 28i.
To the driving electrodes 28a, 28d,
When a positive voltage is applied to 28g and 28j, FIG.
As shown in the figure, the partition walls 21a and 21b are bent toward the flow path 22a, and the partition walls 21d and 21e are connected to the flow path 2a.
Due to the bending displacement toward the 2d side, the ink filled in the flow paths 22a and 22d can be pressurized and ink droplets can be ejected from the ink ejection holes 26.
When the power supply to 8a to 28d and 28g to 28j is cut off,
Partition walls 21a, 21b, 21d, 21e that have been bent and displaced
Return to the original shape by the elastic action, the flow paths 22a, 22
As a result, the ink is supplied from the ink supply holes 24, and the drive electrodes 28a to 28
When the voltage is applied to d, 28g-28j in the opposite direction, the partitions 21a, 21b bend outwardly with respect to the flow path 22d as shown in FIG.
Since d and 21e are bent and displaced outward with respect to the flow path 22d, the pressure in the flow paths 22a and 22d is further reduced and the ink is filled. Next, the driving electrodes 28a to 28d and 28g are driven.
When the energization to .about.28j is cut off, the partition walls 21a, 21b, 21d, 21e which have been bent and displaced return to their original shapes by the elastic action, and enter the next ink droplet ejection stage. By repeating this, ink droplets are continuously discharged.

[0006]

However, the head 30 shown in FIG. 4 is polarized over the entire length of the partition 21, and the driving electrodes 28 extend on both sides of the partition 21 to the vicinity of the nozzle plate 27. Because it is formed as
When the partition wall 21 is bent and displaced in order to discharge ink droplets, the nozzle plate 27 joined to the partition wall 21 is deformed.
6, the ink ejection holes 26 are distorted, or the ink droplets land on the recording medium in a displaced or blurred state, making it impossible to print accurate characters or images. There were challenges.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above problems, and has as its object to prevent (small) variations in the landing positions of ink droplets and to provide high-quality characters and images without color unevenness and image quality disturbance. An object of the present invention is to provide an ink jet printer head capable of printing an image.

[0008]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a flow path member having a plurality of partition walls made of piezoelectric ceramics polarized in a height direction arranged in parallel, and a flow path for ink between the partition walls. A driving electrode formed on the side surface of each partition, a top plate joined to the top surface of each partition and covering each flow channel, and attached to one end of the flow channel member to communicate with each flow channel. An ink jet printer comprising: a nozzle plate having an ink ejection hole to be turned on; an electric current being supplied to the driving electrode to bend and displace the partition to thereby pressurize ink in a flow path and eject ink droplets from the ink ejection hole. In the head, the nozzle plate is attached to a flow path member with a non-polarized piezoelectric ceramic, glass, or insulating ceramic interposed therebetween.

In the present invention, the term “attaching the nozzle plate to the flow path member with non-polarized piezoelectric ceramics or glass or insulating ceramics interposed therebetween” means that the partition wall made of piezoelectric ceramics is near the nozzle plate. Only non-polarized piezoelectric ceramics or glass or insulating ceramics members are bonded to the nozzle plate side of the non-polarized or height-polarized piezoelectric ceramics partition by bonding or the like. Say what you did.

[0010]

According to the present invention, in a piezoelectric type ink jet printer head for pressurizing ink by bending and displacing a partition wall made of piezoelectric ceramics constituting an ink flow path, a piezoelectric ceramic in which a nozzle plate is not polarized, Insulating ceramics containing alumina or zirconia as the main component, or attached to the flow path member with glass in between, so that the partition wall near the nozzle plate is not driven even when the drive electrode is energized, Displacement of the partition in the vicinity of the nozzle plate can be made extremely small or nonexistent, and deformation of the nozzle plate can be suppressed. as a result,
It is possible to prevent (small) displacement and distortion of the ink ejection holes, and to land ink droplets at predetermined positions on a recording medium. Can be obtained.

[0011]

Embodiments of the present invention will be described below.

FIG. 1 is a partially cutaway perspective view showing an example of an ink jet printer head 10 of the present invention. A plurality of partition walls 1 made of piezoelectric ceramics polarized in a height direction are arranged in parallel at equal intervals. A flow path member 3 serving as an ink flow path 2 between the partition walls 1 and an ink for bonding ink to the top surface of each partition 1 so as to cover each flow path 2 and to introduce ink into each flow path 2 A top plate 5 having a supply hole 4 and an ink discharge hole 6 attached to one end of the flow path member 3 by adhesion so as to close each flow path 2 and communicating with each flow path 2 were provided. Driving electrodes 8 are formed on both sides of each partition 1 along the longitudinal direction from the joint with the nozzle plate 7. In addition, the other end side of the flow path member 3 has a closed structure, and 9 is a lead wire of the driving electrode 8.

In order to eject ink droplets using the head 10, ink such as a pigment type oil-based ink, a water-based dye ink, or an ultraviolet curable ink is introduced into each flow path 2 from the ink supply hole 4, and at the same time, This is performed by applying a voltage between the driving electrodes 8 formed on both side surfaces of the partition 1.

As shown in FIGS. 2A and 2B, the driving principle is described, for example, by applying a negative voltage to the driving electrodes 8b and 8c and the driving electrodes 8h and 8i, respectively.
When a positive voltage is applied to 8d, 8g, 8j, the partition 1
The piezoelectric ceramics constituting a, 1b, 1d, 1e undergo shear mode deformation, and as shown in FIG.
a and the partition 1b are bent toward the flow path 2a,
Since the partition walls 1d and 1e are bent toward the flow path 2d, the ink filled in the flow paths 2a and 2d can be pressurized to discharge ink droplets from the ink discharge holes 6, and thereafter,
When the power supply to the driving electrodes 8a to 8d and 8g to 8j is cut off, the partition walls 1a, 1b, 1d, and 1e that have been bent and displaced return to their original shapes by the elastic action, and the pressure in the flow paths 2a and 2d is reduced. As a result, ink is supplied from the ink supply hole 4, and the above-described drive electrodes 8a to 8d, 8g to
When a voltage is applied in reverse to the polarity of 8j, the partitions 1a and 1b bend outwardly with respect to the flow path 2d and the partition 1d and 1e move with respect to the flow path 2d as shown in FIG. Due to the bending displacement to the outside, the inside of the flow paths 2a and 2d is further reduced in pressure and filled with ink.
8d, 8g to 8j are cut off, the partition walls 1a, 1b, 1d, 1e, which have been bent and displaced, return to the original shape by the elastic action, and the next ink droplet ejection stage starts. By sequentially repeating the above operations, the ejection of ink droplets is continuously performed.

Each partition 1 made of piezoelectric ceramics is previously polarized in the height direction, as described above.
The polarization processing is not performed on the piezoelectric ceramics of the partition wall 1 in the vicinity, specifically, within a range of the distance A from the nozzle plate 7.

That is, in the head 10 shown in FIG.
In order to cause the piezoelectric ceramic to bend and displace, the shear mode deformation of the piezoelectric ceramics is used. In order to deform the piezoelectric ceramics in the shear mode, the direction perpendicular to the electric field formed by the driving electrode 8, that is, It is necessary to apply a polarization treatment in the direction of the vertical direction, and the partition wall 1 made of piezoelectric ceramics is entirely polarized along the longitudinal direction due to the relationship with a manufacturing method described later.

However, when the present inventor repeatedly conducted research on the ink jet printer head, the head 10 shown in FIG.
The nozzle plate 7 is placed on one end side of the flow path member 8 as shown in FIG.
When the partition wall 1 is bent and displaced by energizing the driving electrode 8, the position of the ink discharge hole 6 is changed in the nozzle plate 7 with the displacement of the partition wall 1, and the shape of the ink discharge hole 6 is changed. Is found to exert a force to deform the piezoelectric ceramics, so that the polarization process is not applied only to the vicinity of the nozzle plate 7 of the partition wall 1 made of piezoelectric ceramics, so that shear mode deformation is not generated in the piezoelectric ceramics near the nozzle plate 7. By doing so, it has been found that the displacement of the partition 1 in the vicinity of the nozzle plate 7 can be made extremely small or completely absent, and the deformation of the nozzle plate 7 can be suppressed, leading to the present invention.

As a result, the displacement and distortion of the ink ejection holes 6 can be prevented (small), and the head 10 of the present invention can be used to reduce the displacement of ink droplets landing at a predetermined position on the recording medium. Therefore, it is possible to print high-quality characters and images without color unevenness or disturbance of image quality.

By the way, in order to obtain such an effect, it is ideal that the nozzle plate 7 is not affected by the bending displacement of the partition wall 1 at all. It is better that the distance A from the nozzle plate 7 is as long as possible. However, if the distance A is too long, the range in which the partition wall 1 is driven (the area where the partition wall 1 is displaced) is narrowed, and a pressure sufficient to discharge the ink droplets in the flow path 2 cannot be obtained. The reduction in size causes a reduction in the printing speed on the recording medium, and the amount of ejected ink droplets also decreases. In the extreme case, it is impossible to discharge the ink droplet itself.

Therefore, the region not subjected to the polarization treatment, that is,
The distance A from the nozzle plate 7 is 100 μm or more and 28% or less of the length of the partition 1, preferably 100 μm or more and 14% or less of the length of the partition 1.

That is, when the distance A is less than 100 μm, the effect of suppressing the deformation of the nozzle plate 7 due to the bending displacement of the partition wall 1 is small, and the displacement or distortion of the ink ejection holes 6 cannot be prevented. If A exceeds 28% of the length of the partition 1, sufficient pressure cannot be generated in the flow path 2, resulting in a reduction in recording speed and deterioration in image quality.
Next, a method of manufacturing the ink jet printer head 10 shown in FIG. 1 will be described. First, in order to form the flow path member 3, a piezoelectric ceramic mainly composed of lead zirconate titanate (PZT type) and lead magnesium niobate (PMN
A substrate made of a piezoelectric ceramic mainly composed of the above-mentioned main component, a piezoelectric ceramic mainly composed of lead nickel niobate (PNN-based), or a composite of the above-mentioned main components is prepared. Next, the electrodes for polarization are coated on the upper and lower surfaces of the substrate. At this time, the electrodes are formed at the periphery of the end to which the nozzle plate 7 is joined, leaving a distance A. Then, after polarization is applied by applying a voltage, the electrode is removed, so that a polarization process is performed in the thickness direction except for the region of the distance A.

Next, a plurality of grooves are juxtaposed by subjecting the substrate to cutting or blasting using a dicing saw or the like so that a region not subjected to polarization processing becomes an open end. Flow path 2 and flow path 2
The channel member 3 having the partition wall 1 as the partition wall 1 is manufactured.

Next, a mask is applied to both side surfaces of each partition 1 by a photolithography technique or the like, and then platinum, gold, or the like is formed by a film forming means such as vapor deposition, sputtering, or plating.
A drive electrode 8 made of a metal such as palladium, rhodium, silver, nickel, or aluminum, or an alloy mainly composed of platinum-gold, palladium-silver, platinum-palladium or the like is formed along the longitudinal direction. However, the driving electrode 8 is connected to the flow path 2
Is electrically connected to a lead wire 9 extending from the end of the flow path member 3 to the rear end of the flow path member 3, and the drive electrode 8 is energized via the lead wire 9.

Thereafter, a top plate 5 provided with an ink supply hole 4 made of an insulating material such as ceramics, glass, or silicon is provided on the top surface of the partition wall 1 to cover the flow path 2 of the flow path member 3 with an adhesive or the like. A nozzle provided with an ink discharge hole 6 made of resin or the like, together with a partition wall 1 made of unpolarized piezoelectric ceramics at the open end of the flow path member 3 so as to close each flow path 2 at the open end of the flow path member 3 By joining the plates 7 with an adhesive, the head 10 shown in FIG. 1 can be obtained.

Next, another embodiment of the present invention will be described with reference to FIG.
This will be described with reference to FIG.

This ink jet printer head 20
A plurality of partition walls 11 made of piezoelectric ceramics polarized in the height direction are arranged side by side at equal intervals, a space between the partition walls 11 is formed as an ink flow path 12, and one end of the flow path main body 13 is closed. The open ends are made of unpolarized piezoelectric ceramics, insulating ceramics mainly composed of alumina, zirconia, forsterite, steatite or the like, or glass. A flow path member 17 is joined by bonding a flow path auxiliary body 16 having a partition wall 14 and a flow path 15 having the same dimensions as
The head 20 has the same structure as that shown in FIG. 1 except that the drive electrode 8 is energized to form the partition 11.
Partition 14 which constitutes the vicinity of the nozzle plate 7 even when the nozzle 14 is bent and displaced.
Since the nozzles are not displaced, the deformation of the nozzle plate 7 can be suppressed, and the displacement and distortion of the ink ejection holes 6 can be prevented as in the case of the head 10 in FIG.

The partition 14 constituting the flow path auxiliary body 16
Ideally, the nozzle plate 7 is not affected by the displacement of the partition 11 at all.
It is better that the length 4, that is, the distance B from the nozzle plate 7 is as long as possible. However, if the distance B is too long, the range in which the partition wall 1 is driven (the area in which the partition wall 1 is displaced) is narrowed, and sufficient pressure for ejecting ink droplets in the flow paths 12 and 15 cannot be obtained. The reduction in the printing speed causes a reduction in the printing speed on the printing medium, and the amount of the ejected ink droplets also decreases. The image quality on the medium is degraded, and in extreme cases, the ink droplet cannot be ejected.

For this reason, the partition 1 constituting the flow path auxiliary body 16
4, the distance B from the nozzle plate 7 is 100 μm.
m and 28% of the total length from the partition 11 to the partition 14
The thickness is preferably 100 μm or more and 14% or less of the entire length from the partition 11 to the partition 14.

Next, a method of manufacturing the ink jet printer head 20 shown in FIG. 3 will be described. First, the flow path member 17
Lead zirconate titanate (PZT-based) to form
From piezoelectric ceramics mainly composed of lead, piezoelectric ceramics mainly composed of lead magnesium niobate (PMN-based), piezoelectric ceramics mainly composed of lead nickel niobate (PNN-based), or piezoelectric ceramics composed of the above main components A substrate is prepared, and electrodes for polarization are attached to the upper and lower surfaces of the substrate. Then, a voltage is applied to perform polarization, and then the electrode is removed to perform polarization in the thickness direction.

Next, on one end of the substrate, a piezoelectric ceramic mainly composed of unpolarized lead zirconate titanate (PZT type) and lead magnesium niobate (PMN) are used.
Plate material composed of piezoelectric ceramics whose main component is piezoelectric ceramics, piezoelectric ceramics whose main component is lead nickel niobate (PNN-based), or piezoelectric ceramics in which the above main components are combined, or alumina, zirconia, forsterite,
After joining a plate made of insulating ceramics such as steatite or zircon, or a plate made of glass with an adhesive, cutting or blasting using a dicing saw etc., so that the plate side becomes the open end. ,
A plurality of grooves are provided side by side, and the grooves are used as ink flow paths 12 and 15, and walls forming the flow paths 12 and 15 are partitioned by partition walls 11 and 15.
A channel member 17 as 14 is manufactured.

Next, a mask is applied to both side surfaces of each of the partition walls 11 and 14 by a photolithography technique or the like, and then the film is formed by film forming means such as vapor deposition, sputtering, and plating.
Metals such as platinum, gold, palladium, rhodium, silver, nickel, aluminum, and platinum-gold, palladium-silver, platinum-
A drive electrode 8 made of an alloy mainly composed of palladium or the like is formed along the longitudinal direction. However, the driving electrode 8
Are electrically connected to a lead wire 9 extending from the end of the flow passage 2 to the rear end of the flow passage member 3, and the drive electrode 8 is energized via the lead wire 9.

Thereafter, the flow paths 12, 1 of the flow path member 17
A top plate 5 having an ink supply hole 4 made of an insulating material such as ceramics, glass, or silicon is joined to the top surfaces of the partition walls 11 and 14 with an adhesive or glass so as to cover the flow path member 17. The partition walls 11 and 14 made of piezoelectric ceramics which are not polarized or insulating ceramics such as alumina, zirconia, forsterite, steatite, zircon, or glass to close the flow paths 12 and 15 are formed at the open ends of the bases. At the same time, the head plate 20 shown in FIG. 3 can be obtained by joining the nozzle plate 7 having the ink discharge holes 6 made of resin or the like with an adhesive.

The present invention is not limited to the structure shown in FIGS. 1 and 3, and it goes without saying that improvements and design changes can be made without departing from the scope of the present invention.

[0034]

(Embodiment 1) Here, in the ink jet printer head 10 shown in FIG.
An experiment was conducted to examine the presence / absence of displacement or distortion of the ink ejection holes 6 and the ejection speed of the ink droplets when the ink droplets were changed.

In this experiment, a substrate made of lead zirconate titanate-based piezoelectric ceramics was prepared, and screen printing was performed on both surfaces of this substrate except for a region at a distance A from the end surface where the nozzle plate 7 was joined. Palladium (Pb)
-Depositing silver (Ag) to form an electrode for polarization, applying a voltage to perform polarization processing in the thickness direction of the substrate, removing the electrode for polarization by cutting, and then dicing. Cutting multiple grooves with a saw, width 70μm, height 350
A plurality of flow path members 3 in which partition walls 1 having a length of 7,000 μm and a length of 7,000 μm were arranged side by side at a pitch of 141 μm were manufactured. However, the distance A from the non-polarized nozzle plate 7 was varied as shown in Table 1.

Next, a mask was formed on both side surfaces of the partition wall 1 by using the photolithography technique, a driving electrode 8 made of platinum and a lead wire 9 were formed by a sputtering method, and the mask was removed.

Thereafter, a top plate 5 made of alumina ceramic having an ink supply hole 4 is bonded to the top surface of the partition wall 1 with an epoxy-based adhesive. An ink jet printer head 10 was manufactured by joining a polyimide resin nozzle plate 7 having ink discharge holes 6 with an epoxy adhesive.

Then, a current is applied to the driving electrode 8 of each head 10, the partition 1 is driven without supplying ink into the flow path 2, and the degree of distortion of the ink ejection hole 6 is confirmed by an image processing apparatus. Then, each head 10 is incorporated into an ink jet printer for printing, and the ejection speed of ink droplets at this time is
Using a discharge tube as a light source, the position of the ink discharge hole 6 is measured by a high-speed photographing device that records the state of discharge of ink droplets on the film. Evaluation was made by confirming the deviation. That is, a small voltage value is applied to the driving electrode 8 in advance, and the partition 1 is bent and displaced by an amount of displacement that does not cause deformation of the nozzle plate 7 so that ink droplets land on the recording film. Ink droplets were ejected by increasing the voltage value applied to the ink droplets, and the deviation between the landing position of the ink droplet and the landing position of the previous ink droplet was measured by an image processing apparatus.

For comparison, a conventional head 30 in which the distance A from the nozzle plate 7 was 0 mm was also prototyped.
A similar experiment was performed.

In the evaluation, the ejection speed of the ink droplets was adjusted to the sample No. A head having a speed equal to or higher than that of the conventional head of No. 1 and an ink droplet landing position deviation of 15 μm or less was determined to be good.

The results are as shown in Table 1.

[0042]

[Table 1]

As a result, in the conventional ink jet printer head 30, the distortion of the ink discharge holes 26 is large, the discharge speed of the ink droplets is about 5 m / s, and the displacement of the ink droplet landing position is as large as 50 μm or more. Met.

On the other hand, by not subjecting the piezoelectric ceramic constituting the vicinity of the joint between the partition wall 1 and the nozzle plate 7 to polarization treatment, the ejection speed of ink droplets can be increased and the ink ejection holes can be increased. It can be seen that the deformation of No. 6 can be suppressed and the displacement of the landing position of the ink droplet can be reduced. However, the sample No. When the distance A from the nozzle plate 7 is longer than 28% of the entire length of the partition wall 1 as shown in FIGS.
The value was smaller than 0, which was not practical.

As a result, in order to prevent distortion and displacement of the ink ejection holes 6, it is sufficient that the polarization processing is not performed on the piezoelectric ceramics constituting the vicinity of the joint between the partition wall 1 and the nozzle plate 7. In this case, , The distance A from the nozzle plate 7 is
It is preferable that the distance A be 100 μm or more and 28% or less of the entire length of the partition wall 1.
In addition, when the total length of the partition walls 1 is 14% or less, it is possible to prevent distortion and displacement of the ink ejection holes and increase the ejection speed of the ink droplets.

(Embodiment 2) Next, in the ink jet printer head 20 shown in FIG. 3, ink ejection when the length of the partition wall 14 constituting the flow path auxiliary body 16, that is, the distance B from the nozzle plate 7 is changed. An experiment was conducted to examine the presence or absence of displacement or distortion of the holes 6 and the ejection speed of ink droplets.

In this experiment, a substrate made of lead zirconate titanate-based piezoelectric ceramics was prepared, and palladium (Pb)-was screen-printed on both surfaces of this substrate.
Silver (Ag) is applied to form a polarization electrode, a voltage is applied to the substrate, and a polarization process is performed in the thickness direction of the substrate. Then, the polarization electrode is removed by cutting, and then the length is increased. Table 2
After bonding a substrate made of forsteritic ceramics different from that described above to a substrate made of polarized piezoelectric ceramics, a plurality of grooves are cut with a dicing saw to obtain a width of 70 μm, a height of 350 μm, and a length of 7000 μm.
The flow path member 17 in which m partition walls 1 are arranged in parallel at a pitch of 141 μm was manufactured. However, the forsterite ceramic side was set as the open end of the flow path member 17.

Next, masking was performed on both side surfaces of the partition walls 11 and 14 by using a photolithography technique, and a driving electrode 8 and a lead wire 9 made of platinum were formed by a sputtering method, and then the mask was removed.

An alumina ceramic top plate 5 having ink supply holes 4 is joined to the top surfaces of the partition walls 11 and 14 with an epoxy-based adhesive, and the flow path member 17 is formed.
An ink jet printer head 20 was manufactured by joining a polyimide resin nozzle plate 7 having an ink discharge hole 6 to the open end portion thereof with an epoxy adhesive.

Then, the ejection speed of the ink droplets, the degree of distortion of the ink ejection holes 6, and the displacement of the ink ejection holes 6 were confirmed under the same conditions as in Example 1 for each head 20.

The results are as shown in Table 2.

[0052]

[Table 2]

As a result, by providing the flow path auxiliary member 16 made of forsterite ceramics between the flow path main body 13 and the nozzle plate 7, the discharge speed of ink droplets can be increased, and the ink discharge holes can be increased. Suppress the deformation of 6,
Further, it can be seen that the displacement of the landing position of the ink droplet can be reduced. However, the sample No. When the distance B from the nozzle plate 7 is longer than 28% of the entire length of the partition wall 1 as in 19 and 20, the ejection speed of the ink drops becomes smaller than that of the conventional ink jet printer head 30, which is a level that is not practical. .

As a result, in order to prevent distortion and displacement of the ink ejection holes 6, a flow path auxiliary body 16 made of insulating ceramics such as forsterite ceramics is provided between the flow path main body 13 and the nozzle plate 6. In this case, the length of the partition 14 in the flow path auxiliary body 16, that is, the distance B from the nozzle plate 7 is 100 μm or more, and
And the distance A is preferably 100 μm or more and 14% or less of the entire length of the partition wall 1, thereby preventing distortion and displacement of the ink ejection holes, and It was confirmed that the ejection speed of the ink droplets could be increased, which was preferable.

[0055]

As described above, according to the present invention, a plurality of partition walls made of piezoelectric ceramics polarized in the height direction are juxtaposed, and a flow path member having an ink flow path between the partition walls is provided. A driving electrode formed on the side surface of each partition, a top plate joined to the top surface of each partition and covering each flow path, and attached to one end side of the flow path member, and each flow path A nozzle plate having an ink discharge hole communicating therewith, wherein the drive electrode is energized to bend and displace the partition to thereby pressurize ink in the flow path and discharge ink droplets from the ink discharge hole. In the printer head, the nozzle plate is attached to the flow path member with non-polarized piezoelectric ceramics or glass or insulating ceramics interposed therebetween. small Ku or no (or none and delete)
Because it is possible to suppress the deformation of the nozzle plate joined to the partition,
Since the displacement and distortion of the ink ejection holes can be prevented (small), a predetermined amount of ink droplets can be ejected, and the ink droplets can be accurately (reduced in position) at a predetermined position on the recording medium. Can print high-quality characters and images without color unevenness or image quality disturbance.

[Brief description of the drawings]

FIG. 1 is a partially broken perspective view showing an example of an ink jet printer head according to the present invention.

FIG. 2 is a partial cross-sectional view for explaining a driving principle of the ink jet printer head in FIG.

FIG. 3 is a partially broken perspective view showing another example of the inkjet printer head according to the present invention.

FIG. 4 is a partially broken perspective view showing an example of a conventional ink jet printer head.

FIG. 5 is a partial cross-sectional view for explaining a driving principle of the ink jet printer head in FIG.

[Explanation of symbols]

1, 21: partition wall 2, 22: flow path 3, 23: flow path member 4, 24: ink supply hole 5, 25: top plate 6, 26:
Ink ejection holes 7, 27: nozzle plate 8, 28: drive electrode 9, 2
9: Leader lines 10, 20, 30: Inkjet printer head

Claims (1)

[Claims] A plurality of partition walls made of piezoelectric ceramics polarized in a height direction are arranged in parallel, a flow path member serving as an ink flow path between the partition walls, and a driving member formed on a side surface of each partition wall. Electrodes, a top plate that is joined to the top surface of each of the partition walls and covers each flow path, and a nozzle plate that is attached to one end of the flow path member and has an ink ejection hole that communicates with each flow path. An ink jet printer head that pressurizes ink in a flow path and discharges ink droplets from the ink discharge holes by energizing the drive electrode to bend and displace the partition, An ink jet printer head, wherein the ink jet printer head is attached to the flow path member with a piezoelectric ceramic, a glass or an insulating ceramic not interposed therebetween.