JP3495175B2 - Inkjet head - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inkjet head for recording by ejecting ink droplets. In recent years, with the generalization of computers and word processors, many printers, which are one of the output devices of these electronic devices, have been used, and inkjet printers have become popular as one of these printers. Further, there is a demand for improvement in printing quality and cost reduction in an inkjet head mounted in an inkjet printer.

[0002]

2. Description of the Related Art FIG. 20 shows an overall conceptual view of an ink jet printer. The inkjet printer 11 shown in FIG. 20 is one in which a platen roll 12 which is a rotationally driven conveyance means feeds a recording paper 13 wound around a half circumference of an outer surface, and two papers are provided in parallel with the axial direction of the platen roll 12. The stay shafts 14a and 14b are fixed. A carriage 15 is slidably provided on the stay shafts 14a and 14b and is reciprocally driven. This carriage 1
5, the inkjet head unit 16 has nozzles for ejecting ink droplets, which are arranged toward the recording paper 13 side. Then, ink is supplied to the inkjet head unit 16 from the ink reservoir 17 as an ink supply means through the tube 18.

Therefore, FIG. 21 shows an exploded perspective view of a conventional ink jet head. The inkjet head 21 shown in FIG. 21 is configured by arranging a plurality of elements to form the inkjet head unit 16 and is shown by disassembling each part, and is made of metal or plastic having Young's modulus of about 1 × 10 ¹⁰ Pa or more. A pressure chamber 23 is formed by being surrounded by a rectangular flow path plate 22 formed of such a highly rigid member (for example, a photosensitive film).

The pressure chamber 23 is filled with ink liquid from the ink supply port 24, and a nozzle plate 26 having a nozzle hole 25 is joined to the front side (upper side in the drawing) of the ink liquid (described later). To). The nozzle hole 25 faces the outer printing portion (not shown), and the ink liquid in the pressure chamber 23 is ejected from the nozzle hole 25 as an ink droplet toward the printing portion.

On the back surface side of the pressure chamber 23, for example, an elastic elastic layer 27 made of rubber or resin having a Young's modulus of about 1 × 10 ⁵ to 1 × 10 ⁹ Pa is sandwiched between them to elastically deform. A possible pressure plate 28 is arranged. Pressure plate 28
Is formed in a rectangular shape and faces the pressure chamber 23 over the entire surface, and is connected to the support 30 by thin ribs 29 at both ends in the longitudinal direction. It is a free end in the direction perpendicular to it.

On the back surface of the pressure plate 28, a piezo element 31, which is a piezoelectric element that deforms when a voltage is applied, is arranged in close contact with the pressure plate 28. Piezo element 31 for pressure plate 28
Has a rectangular shape, and its longitudinal direction coincides with the longitudinal direction of the pressure plate 28. 32 is an electrode.

FIG. 22 shows a block diagram of a conventional piezoelectric actuator. 22A is a partial perspective view, FIG.
2 (B) is a sectional view. FIG. 22 (A) shows a piezoelectric actuator 33 in which a predetermined number of piezoelectric elements 31 are formed in two rows from a firing block of a piezoelectric member, and electrodes 32 are formed on the opposing surfaces. is there. In this case, the central bottom portion 34 formed by deep half-cutting with respect to the bottom portion of each piezo element 31 is formed low (for example, about 200 μm to 300 μm), and each piezo element 3 is formed.
Insulating grooves 35 for separating the electrodes 32 between the piezo elements 31 are formed from the bottom of the No. 1 to the central bottom 34. Reference numeral 37 is a holder that serves as a guide when the piezoelectric actuator 33 is attached.

Then, as shown in FIG. 22B, the common lead 36a is bonded by soldering or the like while using the electrode 32 on one side of each piezo element 31 as a common electrode, and the electrode 32 on the other side is an individual electrode. The individual leads 36b are similarly bonded. Therefore, in FIG.
FIG. 3 is an explanatory view of an arrangement state of the lead frame of FIG. FIG. 23
FIG. 22A is a partial plan view, and FIG. 22B is a side sectional view. As shown in FIGS. 23A and 23B, each electrode 3 is located above the central bottom portion 34 between the two rows of piezoelectric elements 31.
The common lead 36a formed integrally with the support portion 36c is bonded to the lower side of one side of the second side 2, and the individual lead 36b is bonded to the lower side of the other side.

On the other hand, FIG. 24 shows a joined state of a conventional piezoelectric actuator, and FIG. 25 shows a cross-sectional explanatory view of a main part of FIG. The piezoelectric actuator 33 is configured such that the nozzle plate 26, the flow path plate 22, the elastic layer 27, and the pressure plate 28 of the ink jet head 21 shown in FIG. Bonding is performed while applying a predetermined pressure.

That is, as shown in FIG. 25A, the head portion 21a is formed by the nozzle portion 26a, the flow passage portion 22a, the elastic body portion 27a, and the pressing portion 28a, while the holder 37 of the piezoelectric actuator 33 and An adhesive 38 is applied to the tip of each piezo element 31. And in FIG.
As shown in (B), the piezo elements 31 corresponding to the respective pressure plates 28 are aligned, and the piezo elements 31 are bonded while being pressed with a predetermined pressure.

[0011]

However, as shown in FIGS. 22 and 23, since the common lead 36a and the individual lead 36b are attached to the electrode 32 of the piezoelectric actuator 33 above the central bottom portion 34, the bonding is not performed. Is a single location, and the integrally formed support portion 36c and the common lead 36a are suspended in the air to reduce the strength, and are fixed in the piezo element 31 between blocks (when a plurality of piezoelectric actuators 33 are provided). There is a problem that the positional accuracy and the variation of the displacement amount due to the variation of the polarization deterioration due to the heat at the time of soldering cause the deterioration of the printing quality, and the yield of the subsequent process also decreases and the cost increases.

Further, as shown in FIG. 25, the pressing portion 28a
Is required to have flatness and flatness. However, the piezoelectric element 31 of the piezoelectric actuator 33 and the pressure plate 28 are bonded by an adhesive 38.
Since the holder 37 is directly bonded by the pressure applied to the piezo element 3 by the warp or undulation of the pressure plate 28,
1, a buckling load is applied to the elastic body layer 27, and a compression load is applied to the elastic body layer 27 to reduce the displacement amount of the pressure plate 28 when a voltage is applied.
There is a problem that sufficient flight characteristics of ink particles cannot be obtained, and printing quality is degraded.

Therefore, the present invention has been made in view of the above problems, and an object of the present invention is to provide an ink jet head for improving the printing quality by preventing the variation in the displacement amount of the piezoelectric element.

[0014]

[0015]

[Means for Solving the Problems ] To solve the above problems
According to claim 1, a nozzle plate having a predetermined number of nozzle holes corresponding to one of the flow path plates having a predetermined number of pressure chambers filled with the ink liquid is provided, and the other pressure plate is provided on the other side. A pressurizing unit having a predetermined number of deformable pressurizing plates corresponding to the chamber is provided, and each pressurizing plate is deformed by an actuator having a predetermined number of corresponding driving units to eject ink droplets from the nozzle holes. In the ink-jet head, the actuator includes a predetermined number of comb-shaped drive portions formed in at least two rows, and electrode portions formed on two opposite surfaces of the drive portions so as to extend to the bottom of the bent surface. The center bottom portion between the columns is formed at a height for mounting a support portion having a common lead connected commonly for applying a voltage on one surface of each of the electrode portions. Inkjet head is configured to symptoms.

According to a second aspect of the present invention, the central bottom portion of the first aspect is formed to have a height higher than the height of the bottom portion of each of the driving portions. In the third aspect, the central bottom portion according to the first aspect is formed to have substantially the same height as the height of the bottom portion of each of the drive portions.

According to a fourth aspect of the present invention, the central bottom portion of the first aspect is formed by providing a spacer having a height substantially equal to the height of the bottom portion of each of the driving portions. According to a fifth aspect, in any one of the first to fourth aspects, a corresponding lead for applying a voltage is connected to each of the electrode portions including at least the bottom portion in contact with at least two surfaces.

According to a sixth aspect of the present invention, a nozzle plate having a predetermined number of nozzle holes corresponding to one of the flow path plates having a predetermined number of pressure chambers filled with the ink liquid is provided.
On the other hand, there is provided a pressurizing section in which a predetermined number of deformable pressurizing plates corresponding to the respective pressure chambers are formed, and each of the pressurizing plates is deformed by an actuator in which a predetermined number of corresponding drive sections are formed, and the pressurizing plate is formed from the nozzle hole. In an inkjet head that ejects ink droplets, the actuator includes two drive units.
Electrodes are formed on the two bottom surfaces of the driving portions, which are arranged in rows and which are formed in a comb-like shape, facing each other on the two opposite surfaces, and are provided for applying a voltage to the bottom portions of the respective electrode portions. An ink jet head is constructed in which wires are electrically connected.

[0019]

[0020]

[0021]

As described above, in the inventions of claims 1 to 4,
The drive parts are formed in at least two rows in the shape of a comb, and the electrode parts are formed on the bottoms of the bent parts on the two opposing surfaces of each drive part. The central bottom part between the rows is provided with a common lead. The height is the height at which the portion is placed, and is appropriately higher than the bottom portion, or substantially the same height as the bottom portion, or is formed at substantially the same height as the bottom portion using a spacer. As a result, the support is placed at the center bottom and the leads are fixed, so that the strength is improved, yield is improved in subsequent steps, cost reduction is achieved by improving mass productivity, and the displacement amount of the drive unit is varied. By avoiding this, it is possible to improve the printing quality due to the stability of the ink flying characteristics.

According to the fifth aspect of the invention, the supporting portion is placed on the central bottom portion, and the leads are connected by two surfaces including the bottom portion of the electrode. As a result, it is possible to improve the adhesive strength and the positioning accuracy, reduce the cost, and improve the printing quality due to the stability of the ink flying characteristics from the stability of the displacement amount of the drive unit.

According to the sixth aspect of the present invention, electrode portions are formed on the two opposing surfaces of each driving portion formed in a comb tooth shape so as to extend over the bent bottom portion, and the wires are electrically connected at the bottom portions. As a result, it is possible to easily and flexibly connect the leads for voltage application, which improves flexibility, and avoids polarization deterioration due to heat to stably drive the drive unit, thereby improving print quality. It will be possible.

[0025]

[0026]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a block diagram showing the essential parts of a first embodiment of the present invention. FIG. 1A shows a piezoelectric actuator 41.
_A partial perspective view of _A is shown in FIG. 20 and FIG.
The driving means is used in the inkjet head of the inkjet printer shown in FIG. 1B is a schematic cross-sectional view of FIG.
(C) is a partial enlarged view of a joint portion between a lead and an electrode.

In FIG. 1A, the piezoelectric actuator 4
1 _A is a firing block formed of a piezoelectric member, for example, 2
Formed in the shape of comb teeth in each row and each of the four corners is a guide part 4
2 and the other portion is the piezoelectric element 43 as a driving unit. Then, wide side surfaces 44a of the piezoelectric element 43 that face each other,
44a and bottoms 44b and 4 of the curved surface perpendicular to the lower part
Electrodes 44, 44 are formed on 4b, and a central bottom portion 45 lower than the bottom portions 44b, 44b is formed at a central portion in one direction of the block. In addition, the bottom portion 44 of each piezoelectric element 43
A groove 46 for insulation is formed between b.

On the other hand, as shown in FIGS. 1 (A) and 1 (B), a lead frame 47 as an electrode lead connected to the electrode 44 of each piezoelectric element 43 is prepared (described later), and the lead frame 47 is provided inside. The common lead 47a is arranged and the individual leads 47b arranged on both outer sides. Further, the common lead 47a and the individual lead 47b are formed, for example, in a rectangular shape (round shape or other polygonal shape) in cross section, and the common lead 47a having the electrode 44 on one surface side of each piezoelectric element 43 in common is formed. The electrode 44 on the other side
The individual leads 47b are arranged so as to be individual.

In this case, as shown in FIG. 1 (C), the tips of the common lead 47a and the individual lead 47b are at least the lower portion of the side surface portion 44a and the bottom portion 44b of each piezoelectric element 43.
It is attached by a conductive adhesive material 48 such as solder in a contact state with the two surfaces. Therefore, FIG. 2 shows an explanatory view of the connection state of the lead frame. 2A is a partial plan view and FIG. 2B is a side sectional view. 2 (A),
As shown in (B), first, a predetermined number of common leads 47a.
Is formed integrally with the support portion 47c, and a predetermined number of individual leads 47b are arranged on both sides of the support portion 47c and bent at right angles (see FIG. 1). 47b is the opposing electrode 4 of each piezoelectric element 43.
In FIG. 4, the lower surface of the side surface portion 44a and the bottom surface 44b are bonded to each other.

As a result, the bonding strength can be improved, and the leads can be fixed at a fixed position, so that the piezoelectric elements 43 between the blocks (in the case of an ink jet head using a plurality of piezoelectric actuators) can be fixed. Since the variation in the amount of displacement can be reduced, it is possible to reduce the cost and improve the printing quality by improving the yield.

Here, FIG. 3 shows a manufacturing explanatory view of the piezoelectric actuator of FIG. In FIG. 3A, a firing block 51 formed of a piezoelectric member such as a piezo member is formed into a comb tooth shape by dicing a predetermined number of grooves 52 by half-cutting in a predetermined direction by dicing.
Au (gold) plating 53 is applied using the (nickel) layer as a base to form a portion to be the electrode 44. After that, the tips of the comb teeth are polished, and a groove 46 is formed in each groove 52 with a thin blade at the root portion of the comb teeth, and each Au plating 53 is cut to form each comb tooth (the portion that becomes the piezoelectric element 43). Insulate between.

Then, a half-cut groove 54 which becomes a central groove of the piezoelectric actuator 41 is formed at a predetermined interval in the direction perpendicular to the groove 52 to form a central bottom portion 45, and the piezoelectric elements 43 are arranged in two rows on both sides of the central groove 54. A single piezoelectric actuator 41 is manufactured by full-cutting with a width corresponding to and separating from the firing block 51. When a plurality of piezoelectric actuators 41 _A are separated from one firing block 51, the central groove 54 is formed at a predetermined interval before full cutting.
A predetermined number of half cuts to be
Full cut is performed for each row width.

FIG. 4 shows a plan view of the lead frame used in FIG. 1, and FIG. 5 shows an explanatory view of the bent state of the lead frame of FIG. FIG. 4 shows an original lead frame plate 55 which becomes the lead frame 47 of FIG. 1, and a number of common leads 47a corresponding to the piezoelectric elements 43 are integrally formed on both sides from the central support portion 47c. The corresponding individual lead 47b is integrally formed with the common lead 47a and the portion with the tie bar 56 interposed.

Further, external leads 47d for pulling out the common leads 47a to the outside are integrally formed at the four corners of the support portion 47c. The credor 57 is attached to the tips of the individual leads 47b and the external leads 47d, respectively.
a and 57b are integrally formed, and the piezoelectric actuator 4
It has enough strength to be attached to 1 _A. For example, the lead frame plate 55 is formed by pressing or etching a 42 alloy thin plate to form the pattern shown in FIG. 4 and subjecting the surface to solder plating.

The lead frame plate 55 shown in FIG.
As shown in (A) and (B), the tie bar 56 is bent at a right angle in the same direction on the cradle 57a, 57b side with the support portion 47c as the center. Therefore, FIG. 6 shows an explanatory view of the arrangement state of the lead frame plate of FIG. 5 and the piezoelectric actuator. From the tip side of the piezoelectric element 43 in the piezoelectric actuator 41 _A formed as described in FIG. 3, the lead frame plate 55 of FIG. 5 is arranged so that the support portion 47c is located above the central bottom portion 45 of the piezoelectric actuator 41 _A. To
The portions of the common lead 47a, the individual lead 47c, and the external lead 47d, which are the tips, are connected to the corresponding piezoelectric elements 43.
The lower part of the side surface part 44a and the two surfaces of the bottom part 44b are positioned so as to be in contact with each other (see FIG. 1C).

In this case, for example, solder is laid on the tip end portion, and each lead 47a, 47b, 47d is fixed to the electrode 44 by reflowing. Then, the tie bar 56 and the credors 57a, 57
By cutting b, the piezoelectric actuator 41 _A connected to the pressing portion (28a) as shown in FIGS. 24 and 25 is formed.
_An ink jet head is constructed by fixing _A to the pressure part (head part) with an adhesive.

[0037] That is, when securing the piezoelectric actuator 41 _A, each lead 47a, 47b, since the 47d of the fixing is firm, it is possible to improve the yield by pressurization, the leads 47a, 47b , 47d
The fixed position is fixed and the variation in the displacement amount of each piezoelectric element 43 (including the piezoelectric element between each block) is reduced, so that the print quality can be improved due to the stable ink flying characteristics.

Next, FIG. 7 shows a block diagram of the essential parts of a second embodiment of the present invention. FIG. 7A shows the piezoelectric actuator 41 _B.
FIG. 7B is a partial perspective view of the lead frame (excluding the lead frame), and FIG. In the piezoelectric actuator 41 _B shown in FIG. 7A, the height (b) of the central bottom portion 45 a formed by the central groove between the two rows of piezoelectric elements 43 is the height (a) of the bottom 44 b of the electrode 44 in the piezoelectric element 43 (a ), The grooves 46a, 46a for forming the central bottom portion 45a independently are formed in the column direction.

In the manufacturing in this case, the grooves 46a and 46a are formed by dicing after the processing of the central groove 54 by the half cut in the step of FIG. 3 is performed at the above height (b). The lead frame 47 is shown in FIG.
As shown in (B), an opening 47e corresponding to the central bottom portion 45a is formed by etching or the like in a supporting portion 47c integrally formed with a common lead 47a, and a conductive adhesive material is further provided by printing. Then, the central bottom portion 45a is brought into a fitted state through the opening portion 47e, and pressure is applied on the bottom portion 44a to bond them.

The individual lead 47b is not shown in FIG. 7B, and the formation of the piezoelectric element 43, the electrode 44, etc. and the other formation of the lead frame 47 are the same as in the first embodiment. . The common lead 47a, the individual lead 47b, and the external lead 47d of the lead frame 47 may be connected in the same manner as in FIG. 1C, or may be connected on only one surface.

According to the second embodiment, when a plurality of blocks as shown in FIG. 7 (A) are used, it is possible to reduce the variation in the displacement amount of the piezoelectric element 43 between the blocks, and at the same time, the piezoelectric Since the element 43 is cured at a temperature at which the polarization does not deteriorate, the polarization deterioration can be prevented, and the printing quality can be improved by stabilizing the ink flying characteristics. Further, the lead frame 47 is positioned with high accuracy and the electrodes can be taken out by a method other than soldering.

Next, FIG. 8 is a block diagram showing the essential parts of a third embodiment of the present invention. FIG. 8A shows a piezoelectric actuator 41c.
8 is a partial perspective view of FIG. 8 (lead frame is omitted), FIG.
(B) is a schematic side sectional view. The piezoelectric actuator 41c shown in FIG.
The electrode 44 is formed at substantially the same height as the bottom portion 44b of the electrode 44, and the other structure is similar to that of FIG. 7 (A).

In this case, as shown in FIG. 8B, it is not necessary to form the opening 47e as shown in FIG. 7B in the supporting portion 47c integrally formed with the common lead 47a of the lead frame 47. The supporting portion 4 is formed on the portion of the central bottom portion 45b where the plating portion is formed and the portion where the plating portion is not formed during electrode formation.
7c is placed and pressure-bonded with an adhesive or the like. Note that the common lead 47a, the individual lead 47b, and the external lead 47d are bonded (soldered) to the electrode 44 as shown in FIG.
Similar to (C), it may have two sides or only one side. The soldering is performed using, for example, a high frequency electromagnetic welder or near infrared rays.

According to the third embodiment, since the lead frame 47 is fixed on the central bottom portion 45b, the yield at the time of assembly and assembly, the mass productivity can be improved, and the integration is possible. In addition, it can be advantageous in strength. Further, similarly to the above, it is possible to reduce the variation of the displacement amount of the piezoelectric element 43, reduce the polarization deterioration and the variation of the displacement amount, and it is possible to improve the printing quality by stabilizing the ink flying characteristics. Furthermore, each lead 4
By bonding 7a, 47b, and 47d with near infrared rays, soldering can be performed without contact.

Next, FIG. 9 shows another embodiment of the third embodiment.
FIG. The piezoelectric actuator shown in FIGS.
Quutator 41_DIs the piezoelectric actuator shown in FIG.
41 _AOn the central bottom portion 45 of the piezoelectric element.
Substantially the same as the height to the bottom portion 44b of the electrode 44 of the child 43.
With a spacer 58 of one thickness attached, as shown in FIG.
It has the same function as. This spacer 58
Has a high hardness of 0.5 mm, high workability, and heat resistance.
The member is formed of, for example, ceramics.

Although the lead frame (47) is omitted in FIGS. 9A and 9B, the arrangement and connection are shown in FIG.
It is similar to (B). As a result, the same effect as in FIG. 8 can be obtained. Next, FIG.
FIG. 9 is a configuration diagram of the essential parts of the fourth embodiment of the present invention. Figure 10
1A is a partial plan view of the piezoelectric actuator 41 _E , FIG.
0 (B) is a partial sectional view. In the piezoelectric actuator 41 _E shown in FIGS. 10A and 10B, the electrodes 44 are formed on the piezoelectric elements 43 arranged in two rows.
This is the same as the state in which the lead frame 47 (common lead 47a, individual lead 47b) is removed, and the electrodes are taken out by bonding on the bottom portion 44b of the electrode 44 with wires 59 such as Au (gold). .

According to this, the electrode can be directly and flexibly taken out from the outside, the polarization deterioration due to heat is prevented, the variation among the piezoelectric elements 43 is reduced, the ink flying characteristics are stabilized, and the printing quality is improved. Can be improved. In addition, it is possible to easily determine whether the piezoelectric actuator is a good product or a defective product.

Next, FIG. 11 shows a sectional view of the essential portions of the fifth embodiment of the present invention. FIG. 11 is a partial cross-sectional view of the inkjet head 61 of the present invention, in which a predetermined number of nozzle holes 63 formed by a tapered portion 63a and a straight portion 63b are formed in the nozzle plate 62, and the nozzle plate 62 is formed on the nozzle plate 62. The flow path plate 64 is arranged. The flow path plate 64 has an opening corresponding to the nozzle hole 63 and an ink supply path (not shown in the figure) communicating with the opening. The opening serves as the pressure chamber 65.

An elastic layer 66, which is an elastic body, is formed on the flow path plate 64, and a pressing portion 67 is attached on the elastic layer 66. The pressurizing portion 67 is formed by integrally forming a pressurizing plate 67a corresponding to the pressure chamber 65 from a support frame via a rib (not shown in the drawing), and the pressurizing plate 6a is bent by the rib to bend the pressurizing plate 6a.
7a applies positive pressure and negative pressure to the pressure chamber 65.

The head portion 68 is formed with such a structure, but this structure is similar to the conventional structure (see FIG. 25). The piezoelectric actuator 41 is provided on the pressing unit 67.
_F is placed. This piezoelectric actuator 41 _F has a predetermined number of piezoelectric elements 43 formed in a comb shape between the guide portions 42 at both ends.
7a corresponds to the position. In this case, the position of the end face of the piezoelectric element 43 is formed to be shorter than the position of the end face of the guide portion 42 by the step d, and an adhesive layer 69 of, for example, an epoxy adhesive is interposed between the pressure plates 67a. .

That is, a step d is formed on the end face of each piezoelectric element 43.
The piezoelectric actuator 41 _F having the adhesive layer 69 made of an adhesive member having the above height is pressed against the pressing portion 67 to be adhered. For example, the step d is set by the coating height of the adhesive member to be the adhesive layer 69 and the rigidity of the piezoelectric actuator 41 _F and the pressure plate 67a through the adhesive layer 69, and is, for example, 5 μm to 50 μm. Is set. This is because when the step d is less than 5 μm, the waviness of the head portion 68 is about ± 2 μm, and a compressive load is applied to the elastic layer 66, and when the step d exceeds 50 μm, the Young's modulus is This is because it becomes 3 GPa, which is lower than the other constituent members, the rigidity is lowered, and the transmission efficiency is lowered. Incidentally, the Young's modulus of the guide portion 42 is about 20 GPa, and the Young's modulus of the piezoelectric element 43 is about 50 GPa.

With this structure, the guide portion 42 is joined to the pressing portion 67, and the piezoelectric element 4
3 prevents the compressive load on the elastic layer 66 and the buckling load on the piezoelectric element 43 itself, which are generated when the pressure part 67 is bonded, from being applied by the adhesive layer 69 interposed between the pressure element 67 and the pressure plate 67a. As a result, the ink flying characteristics can be stabilized and the printing quality can be improved.

Here, FIG. 12 shows a manufacturing explanatory view of the piezoelectric actuator of FIG. One end surface of the firing block 71 of a piezoelectric member such as a piezo member shown in FIG.
As shown in FIG. 12B, the step portion 72 is formed by cutting with a dicing saw or slicer at a depth of the step d, leaving a portion to be the guide portion 42. Then, as shown in FIG. 12C, the portions having the step portions 72a are half-cut with a dicing saw at predetermined intervals to form grooves 73, thereby forming a predetermined number of piezoelectric elements between the guide portions 42 at both ends. 43 is formed. It should be noted that each piezoelectric element 43 has electrodes (not shown) as shown in FIG. 1A described above, and the electrodes are taken out by a lead frame or wire bonding.

Therefore, FIG. 13 shows an overall exploded view of the fifth embodiment. The inkjet head 61 shown in FIG.
The piezoelectric actuator 41 _F shown in FIG. 12 is used in four rows, and a nozzle plate 62 having nozzle holes 63 formed in four rows, a pressure chamber 65 corresponding to the nozzle hole 63, and ink in the pressure chamber 65. A flow path plate 64 in which a common ink supply path 64a for supply is formed and an elastic layer 66 of an elastic member in which an opening 66a corresponding to the pressure chamber 65 is formed.
And the pressurizing plate 67a corresponding to the pressure chamber 65 are sequentially combined with the pressurizing portion 67 which is formed by a rib so that the head portion 68 is configured.

On the other hand, four piezoelectric actuators 41
_F is installed in the head holder 74 with the pressure plate 67a corresponding to the piezoelectric element 43. In this case, the head holder 7
4 is provided with a strobe 75 for supporting the guide portion 42 so as to align the piezoelectric actuator 41 _F. Then, although not shown, the adhesive layer 69 is applied to the tip of each piezoelectric element 43, and the pressure is applied to each pressure plate 67a to apply pressure, thereby forming an inkjet head 61 having four-row nozzle holes. Is.

Further, FIG. 14 shows an operation explanatory view of the ink ejection of FIG. FIG. 14A shows a state in which no voltage is applied to the piezoelectric element 43, and the inside of the pressure chamber 65 is in an unloaded state. Then, as shown in FIG. 14B, when a voltage is applied to the piezoelectric element 43, the piezoelectric element 43 is displaced, the pressure plate 67 a is pulled through the adhesive layer 69, and the elastic layer 66 is deformed. At this time, the pressure inside the pressure chamber 65 becomes negative, and the ink liquid 70 is supplied from the ink supply path 64a.

Subsequently, when the voltage application to the piezoelectric element 43 is stopped, the piezoelectric element 43 returns to its original state and the pressure chamber 6
Apply pressure in 5. As a result, the ink particles 70a are ejected from the nozzle holes 63. Then, Fig. 1
5 shows a cross-sectional view of the main part of another embodiment of the fifth embodiment, and FIG. 16 shows a partial cross-sectional view from the X direction of FIG.
The inkjet head 61 shown in FIG. 15 and FIG.
The piezoelectric actuator 41 _{G is connected} to the guide portion 42a and the piezoelectric portion 4
The guide part 42 is attached to the printed circuit board 76 by being separated into 3a.
a is fixed and the common lead 47 a and the individual lead 47 taken out from the electrodes facing each piezoelectric element 43.
b is mounted by solder 77, and the other configuration is shown in FIG.
Is the same as.

Thus, the guide portion 42a and the piezoelectric portion 43a are
By forming the piezoelectric actuator 41 _G by separating the above and, it is possible to make the cost lower than the case where the whole is formed of an expensive piezoelectric member such as a piezoelectric member. Next, FIG. 17 shows a sectional view of an essential part of another embodiment of the fifth embodiment. In the inkjet head 61 shown in FIG. 17, the end face of the guide portion 42 of the piezoelectric actuator 41 _H is arranged in the same row as the position of the end face of the piezoelectric element 43, and the laminated portion 78 is interposed on the end face of the guide portion 42. Is the same as that of FIG. The height of the laminated portion 78 is set to 5 μm or more in consideration of the waviness of the pressing portion 67 of ± 2 μm, and the height at which the adhesive layer 69 can be applied (wettability between the pressing plate 67a and the piezoelectric element 43). ), And the Young's modulus of the adhesive layer 69 is 5
It should be 0 μm or less.

The laminated portion 78 is selected to have a Young's modulus higher than that of the adhesive layer (Young's modulus 3 GPa) 69. For example, liquid polyimide (Young's modulus 4 GPa), resin film (PET (polyethylene terephthalate): P).
EN (polyethylene naphthalate) Young's modulus 6-7G
Pa) and a liquid resist (Young's modulus 4 GPa) are used.

Therefore, FIG. 18 shows a manufacturing explanatory view of the piezoelectric actuator of FIG. In FIG. 18, a patternable laminated member 80 such as a liquid resist or DFR (dry film resist) is laminated on one surface of a block 79 obtained by firing a piezoelectric member such as ceramics, and as shown in FIG. Exposure and imaging are performed by patterning leaving a portion to be the portion 42, and the laminated portions 78, 78 are formed. Then, as shown in FIG. 18C, grooves 73 are formed by half-cutting with a dicing saw at predetermined intervals between the laminated portions 78 to form a predetermined number of piezoelectric elements 43.

The piezoelectric elements 43 are the same as those shown in FIG.
An electrode (not shown) as shown in (A) is formed, and an electrode is taken out by a lead frame or wire bonding. Other methods of forming the laminated portion 78 include a method of using screen printing and a method of using metal plating (electroless plating).

Thus, the laminated portion 78 as shown in FIG.
The same effect as that of the inkjet head 61 shown in FIG. 11 can be obtained by forming the. Next, FIG. 19 shows another configuration diagram of the piezoelectric actuator of the fifth embodiment. As shown in FIG. 19 (A), for example, a holder 81 in which a ceramic having a Young's modulus of 50 GPa or more is formed in a "U" shape is prepared, and a block in which a piezoelectric member such as a piezo member is fired (Young's modulus is, for example, 5
0 GPa or more) 82 is prepared. The block 82 is sized to fit in the recess of the holder 80, and
As shown in (B), it is formed in a size that forms a step with the end surface of the holder portion 81 when fitted.

Then, as shown in FIG. 19C, the block 82 is half-cut at a predetermined interval with a dicing saw to form grooves 73, whereby a predetermined number of piezoelectric elements 4 are formed.
3 is formed. As a result, the piezoelectric actuator 41 _I having a step between the end face of the holder 81 and the end face of the piezoelectric element 43 can be formed by using both ends of the holder 81 as the guides 42, as in the shape shown in FIGS. 12 and 18. However, the same effect as described above can be obtained.

According to this, in consideration of the fact that the piezoelectric actuator 41 _F shown in FIG. 12 described above has approximately 50% of the other portions forming the piezoelectric element 43,
Block 8 formed with piezoelectric element 43 as shown in FIG.
By forming only 2 with a piezoelectric member and forming the other holder portion 81 with an inexpensive member (ceramics or the like),
The piezoelectric actuator 41 _I that is inexpensive as a whole can be obtained. Further, the holder portion 81 is attached to the block 8
Since it is formed of a member having a Young's modulus equivalent to 2, it is possible to prevent the entire vibration of the piezoelectric element 43 when the piezoelectric element 43 is driven, and to stabilize the flight of ink particles.

[0065]

[0066]

As described above, according to the invention of claim 1.
For example, the driving parts are formed in at least two rows in the shape of a comb and the electrode parts are formed on the opposite two surfaces of each driving part to the bottoms of the bent parts, and a common lead is formed at the central bottom part between the rows. The height at which the supporting portion is placed, which is appropriately higher than the bottom portion, or is approximately the same height as the bottom portion, or is formed at approximately the same height as the bottom portion using a spacer, so that the supporting portion is placed at the central bottom portion. The stability of the ink flight characteristics is improved because the strength is improved by placing it on the lead and the lead is fixed, the yield is improved in the subsequent process, the cost is reduced by improving the mass productivity, and the variation in the displacement of the drive unit is avoided. It is possible to improve the printing quality due to.

According to the invention of claim 5, the supporting portion is placed on the central bottom portion, and the leads are connected by the two surfaces including the bottom portion of the electrode, thereby improving the adhesive strength and the positioning accuracy. As a result, it is possible to reduce the cost and improve the printing quality due to the stability of the ink flying characteristics from the stability of the displacement amount of the drive unit.

According to the sixth aspect of the present invention, the electrode portions are formed on the opposite two surfaces of each of the driving portions formed in the comb tooth shape so as to extend over the bent bottom portion, and the wires are electrically connected at the bottom portions. By doing so, it is possible to easily and flexibly connect the leads for voltage application and improve flexibility, and avoid deterioration due to heat to drive the drive unit stably and improve print quality. it can.

[0069]

[Brief description of drawings]

FIG. 1 is a configuration diagram of a main part of a first embodiment of the present invention.

FIG. 2 is an explanatory diagram of a connected state of the lead frame of FIG.

3A and 3B are manufacturing explanatory views of the piezoelectric actuator of FIG.

4 is a plan view of the lead frame plate used in FIG. 1. FIG.

5 is an explanatory view of a bent state of the lead frame plate of FIG.

FIG. 6 is an explanatory diagram of an arrangement state of the lead frame plate of FIG. 5 and a piezoelectric actuator.

FIG. 7 is a configuration diagram of essential parts of a second embodiment of the present invention.

FIG. 8 is a configuration diagram of main parts of a third embodiment of the present invention.

FIG. 9 is a main part configuration diagram of another embodiment of the third embodiment.

FIG. 10 is a configuration diagram of main parts of a fourth embodiment of the present invention.

FIG. 11 is a main part configuration diagram of a fifth embodiment of the present invention.

FIG. 12 is a manufacturing explanatory diagram of the piezoelectric actuator of FIG. 11;

FIG. 13 is an overall exploded view of the fifth embodiment.

FIG. 14 is an explanatory diagram of an operation of ink ejection of FIG. 11.

FIG. 15 is a sectional view of a main portion of another embodiment of the fifth embodiment (1)
Is.

16 is a partial cross-sectional view from the X direction of FIG.

FIG. 17 is a sectional view of a main portion of another embodiment of the fifth embodiment (2)
Is.

FIG. 18 is a manufacturing explanatory diagram of the piezoelectric actuator of FIG. 17;

FIG. 19 is another configuration diagram of the piezoelectric actuator of the fifth embodiment.

FIG. 20 is an overall configuration diagram of an inkjet printer.

FIG. 21 is an exploded perspective view of a conventional inkjet head.

FIG. 22 is a configuration diagram of a conventional piezoelectric actuator.

FIG. 23 is an explanatory diagram of an arrangement state of the lead frame in FIG. 22.

FIG. 24 is an explanatory diagram of a bonded state of a conventional piezoelectric actuator.

25 is a cross-sectional view of the main parts of FIG.

[Explanation of symbols]

41 _{A to} 41 _I Piezoelectric actuator 42 Guide portion 43 Piezoelectric element 44 Electrodes 45, 45a Central bottom portion 46 Groove 47 Lead frame 47a Common lead 47b Individual lead 48 Conductive adhesive 58 Spacer 61 Inkjet head 62 Nozzle plate 63 Nozzle hole 64 Channel plate 65 Pressure Chamber 66 Elastic Layer 67 Pressing Section 67a Pressing Plate 68 Head Section 69 Adhesive Layer 70 Ink Liquid

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akira Iwaishi 1015 Kamiodanaka, Nakahara-ku, Kawasaki City, Kanagawa Prefecture, Fujitsu Limited (72) Inventor Shuji Koike, 1015, Kamedotachu, Nakahara-ku, Kawasaki City, Kanagawa Prefecture, Fujitsu Limited ( 56) References JP-A-7-290705 (JP, A) JP-A-5-275600 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B41J 2/045 B41J 2/055

Claims (6)

(57) [Claims] 1. A nozzle plate having a predetermined number of nozzle holes corresponding to one side of a flow path plate having a predetermined number of pressure chambers filled with ink liquid is provided, and the other pressure plate is provided in each pressure chamber. An ink jet head provided with a pressurizing unit in which a predetermined number of corresponding deformable pressurizing plates are formed, and each pressurizing plate is deformed by an actuator in which a predetermined number of corresponding drive units are formed to eject ink droplets from the nozzle holes. In the above, the actuator has a predetermined number of comb teeth.
The driving unit is formed in at least two rows, and
The electrode part extends from the bottom of the bent surface to the two opposite surfaces of the moving part.
Are formed, and the central bottom portion between the rows is shared by one surface of each of the electrode portions.
Forming a common lead that is connected for voltage application
An ink jet head, characterized in that it is formed at a height for mounting the above-mentioned supporting portion . 2. The center bottom portion according to claim 1,
An inkjet head characterized in that it is formed to be higher than the height of the bottom of the section . 3. The center bottom portion according to claim 1,
An inkjet head, which is formed to have substantially the same height as the bottom of the portion . 4. The center bottom portion according to claim 1,
There is a spacer that is approximately the same height as the bottom of the
An inkjet head characterized by being formed as follows . 5. The method according to claim 1, wherein
Corresponding leads for applying voltage to each electrode part
Are connected by abutting at least two surfaces including the bottom.
Inkjet head characterized by being 6. A predetermined number of pressure chambers filled with ink liquid
Predetermined nozzle holes corresponding to one of the formed flow path plates
A number of nozzle plates are provided and the other pressure plates are
Pressurization with a predetermined number of deformable pressure plates corresponding to the force chamber
Is provided, and the drive unit corresponding to each pressure plate has a predetermined number
It is deformed by the formed actuator and
Inkjet head that ejects ink droplets
In the actuator, when the drive units are arranged in two rows,
Both of which are opposed to each other by a predetermined number of drive parts formed in a comb tooth shape.
The electrode part is formed on the two surfaces that
A wire for applying a voltage is provided on the bottom of each of the electrode portions.
An ink jet head characterized by being electrically connected .