JP2003237080A - Ink-jet printer head - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent the electric short circuit accident, or the like by preventing diffusion or leakage of an unhardened part of a UV adhesive 7 to a part without the reach of an ultraviolet ray of the rear surface of a head unit 6, or preventing direct contact of a conductive part with the unhardened part of the UV adhesive. <P>SOLUTION: Adhesive inlet holes 9a, 9b facing the rear surface of the side rim parts of a head unit 6 are formed in a bottom plate 5 of a head holder. Projecting bar members 90 comprising an elastic member are provided along the longer sides on the side parts of the rear surface of the head unit 6 having a nozzle. With the lower surface of the bottom plate 5 and the rear surface of the head unit 6 superimposed, the rear surface width direction central part of the head unit 6 and the adhesive inlet holes 9a, 9b are sectioned by the projecting bar members 90, so that drastic leakage of the UV adhesive 7 from the adhesive inlet holes 9a, 9b to the head unit rear surface side can be prevented. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a piezoelectric type ink jet printer head.

[0002]

2. Description of the Related Art In an on-demand type ink jet printer head of the prior art, an ink jet head unit (hereinafter simply referred to as a head unit) in which nozzle rows are arranged in a direction orthogonal to a printing direction has a plurality of nozzles. A pressure chamber formed for each of the nozzles, a cavity plate provided with a common ink chamber (manifold chamber) for supplying ink to the plurality of pressure chambers, and a cavity plate provided on the back side of the cavity plate. The present applicant, as a method of fixing this head unit to the bottom plate of the head holder, is composed of a piezoelectric actuator having each drive unit and a flexible flat cable that transmits an electric signal to the piezoelectric actuator. First, in Japanese Patent Application No. 2000-260616, a head holder The bottom plate of the head unit is provided with an adhesive pouring hole exposed on the side edge of the head unit and the back surface of the protective cover, and a plurality of head units are arranged in parallel on the lower surface side of the bottom plate, and the adhesive pouring hole is formed. A photo-curable adhesive, for example, a UV adhesive, is hung from the bottom plate to bond and fix the head unit and the protective cover to the bottom plate.
It was proposed that the periphery of the protective cover be bonded and fixed to the bottom plate with a sealant.

In the ink jet printer head, in order to improve printing accuracy, it is necessary to accurately determine the position of the ink jet nozzle with respect to the head holder and fix the head unit. Therefore, as described above, the bottom surface side of the bottom plate is used. A plurality of head units are arranged in parallel with each other, and a UV adhesive is dripped from the upper surface side of the bottom plate through the adhesive pouring hole, and the adhesive pouring hole is applied to the UV adhesive from the upper surface side of the bottom plate. Ultraviolet rays were radiated and radiated through the resin to solidify in a short time.

[0004]

However, when the ultraviolet rays are irradiated from the upper surface side of the bottom plate toward the adhesive pouring hole, the head on the lower surface side of the bottom plate and on the outer peripheral portion of the adhesive pouring hole. The UV adhesive does not reach the UV adhesive flowing out to the back side (back side) of the unit, and the uncured portion of the UV adhesive remains.

When the uncured portion of the UV adhesive is in contact with the piezoelectric actuator or the flexible flat cable in the head unit, the uncured portion has a low insulation property, and therefore the piezoelectric element is not used during the use of the inkjet. There is a problem that a weak current leaks from the actuator or the flexible flat cable through the uncured portion, causing an electrical short circuit accident.

In order to prevent the formation of such an uncured portion, there is a problem that it takes a long time to irradiate the ultraviolet rays and the manufacturing cost becomes high. Furthermore, the UV
The solidification (adhesion) points between the head unit or the protective cover and the bottom plate of the head holder by the adhesive are partial, and the other points are sealed with a sealant such as silicone to prevent ink from entering. If there is a contact portion (mixed portion) between the sealant and the UV adhesive that has not solidified, neither curing of the UV adhesive nor solidification of the sealant due to the ultraviolet irradiation can be achieved at that portion, and the above-mentioned electric It was not possible to solve the problem of accidental short circuit and the occurrence of imperfect seals.

The present invention has been made to solve the above-mentioned conventional problems. The unhardened portion of the photocurable adhesive is diffused to a portion of the back surface of the head unit 6 where light such as ultraviolet rays cannot reach. To provide an inkjet printer head that solves the above-mentioned problems by providing a means for preventing leakage and for preventing an uncured portion of the photocurable adhesive from directly contacting a conductive portion. This is a technical issue.

[0008]

In order to achieve the above-mentioned technical object, the invention according to claim 1 provides a head unit having a plurality of nozzles arranged in a row on the front surface on a bottom plate of a head holder. In an inkjet printer head fixed with a photo-curable adhesive, the bottom plate is
Adhesive pouring holes are formed on the back surface of the side edge portion of the head unit, and an elastic member is interposed between the bottom surface of the bottom plate facing the back surface of the head unit and the back surface of the head unit. It is configured to prevent the photo-curable adhesive from the adhesive pouring hole from largely leaking to the back surface side of the head unit.

According to a second aspect of the invention, in the ink jet printer head according to the first aspect, the elastic member is a ring body surrounding the outer periphery of the adhesive pouring hole.

The invention described in claim 3 is the same as claim 1
In the ink jet printer head described in the above item 1, the elastic member is a ridge body disposed between the lower surface of the bottom plate near the adhesive pouring hole and the back surface of the head unit.

On the other hand, the invention according to claim 4 is an ink jet system in which a head unit having a plurality of nozzles arranged in a row on the front surface is fixed to the bottom plate of the head holder via a photo-curing adhesive. In the printer head, an adhesive pouring hole is formed in the bottom plate so as to face a back surface of a side edge portion of the head unit, and a portion of the bottom plate near an outer periphery of the adhesive pouring hole is provided on the back surface of the head unit. On the other hand, it is formed in a close portion having a small gap, and on the lower surface of the bottom plate or the back surface of the head unit in the close portion,
A reservoir groove is formed to prevent the photo-curable adhesive from the adhesive pouring hole from diffusing and leaking from the proximity portion to the back surface side of the head unit.

According to a fifth aspect of the present invention, in the ink jet printer head according to the fourth aspect, one or a plurality of recesses are formed in the reservoir groove in a direction substantially parallel to a direction in which the nozzle row extends. .

Further, according to a sixth aspect of the present invention, an ink jet system is formed by fixing a head unit having a plurality of nozzles arranged in a row on the front surface to a bottom plate of a head holder via a photo-curing adhesive. In the printer head, an adhesive pouring hole is formed in the bottom plate so as to face a back surface of a side edge portion of the head unit, and a portion of the bottom plate near an outer periphery of the adhesive pouring hole is provided on the back surface of the head unit. On the other hand, the external electrodes on the side surface of the piezoelectric actuator are arranged along the concave groove provided on the back surface side of the head unit while being formed in the adjacent portion having a small gap, and the external electrode and the concave groove are formed. It is covered with an electrically insulating material.

Further, according to a seventh aspect of the invention, in the ink jet printer head according to the sixth aspect, the piezoelectric actuator is provided with a through hole communicating from the lower surface of the bottom plate toward the concave groove. However, the electrically insulating material is a sealing agent such as silicone that fills the lower surface of the bottom plate, the through hole, and the groove.

According to an eighth aspect of the present invention, in the ink jet printer head according to any of the first to seventh aspects, a protective cover having an opening window surrounding the nozzle row of the head unit is provided in the head unit. It is arranged on the front surface, and the head unit and the protective cover are fixed by the photocurable adhesive.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a perspective view showing a color ink jet printer which is one of the embodiments of the ink jet recording apparatus of the present invention, and FIGS. 2 to 4 are perspective views of a piezoelectric ink jet printer head according to the embodiment of the present invention. FIG. 5 is a side sectional view of a main part.

The color ink jet printer 100 according to the present invention is for printing on an ink cartridge 61 filled with four color inks of cyan, magenta, yellow and black, and a paper (recording medium) 62, for example. An inkjet printer head 63 including an inkjet head unit (hereinafter simply referred to as a head unit) 6, and a carriage 6 on which the ink cartridge 61 and the inkjet printer head 63 are mounted.
4, a drive unit 65 for reciprocating the carriage 64 in a direction orthogonal to the conveyance direction of the paper 62, a platen roller 66 extending in the reciprocating direction of the carriage 64 and facing the head unit 6, and a purging device. And 67.

The drive unit 65 is arranged at the lower end of the carriage 64 and extends in parallel with the platen roller 66, and a guide plate 72 arranged at the upper end of the carriage 64 and extends parallel to the carriage shaft 71. Two pulleys 73, 7 arranged between the carriage shaft 71 and the guide plate 72 and arranged at both ends of the carriage shaft 71.
4 and a timing belt 75 wound around the pulleys 73 and 74.

The carriage 64 joined to the timing belt 75 by the driving force from one pulley 73 that rotates according to the drive of the motor 76 is the carriage shaft 71.
It is supported by the guide plate 72 and can reciprocate linearly.

The paper 62 conveyed in the direction of the arrow from a paper supply unit (not shown) is introduced between the platen roller 66 and the head unit 6 and is predetermined by the ink ejected from the head unit 6 as described later. Is printed,
After that, the paper is discharged.

The purging device 67 is provided on the side of the platen roller 66 and is arranged so as to face the head unit 6 when the printer head 63 is in the reset position. The purging device 67 includes a purge cap 81 that abuts against an opening surface of a nozzle of the head unit 6 so as to cover a plurality of nozzles 11 a described later, and a pump 82.
And a cam 83 and an ink storage portion 84. When the printer head 63 is in the reset position, the defective ink containing bubbles or the like accumulated inside the head unit 6 is sucked by the pump 82 by the driving of the cam 83 so that the head unit 6 can be recovered. There is. The sucked defective ink is stored in the ink storage unit 84.
Stored in.

Platen roller 6 in purging device 67
A wiper member 86 is arranged adjacent to the purging device 67 at a position on the 6 side. The wiper member 86 is formed in a spatula shape, and wipes the nozzle forming surface of the head unit 6 as the carriage 64 moves. The wiper member 86 is projected upward when the nozzle forming surface is wiped, and is retracted downward when the nozzle forming surface is not wiped.

The cap 85 covers the plurality of nozzles 11a of the head unit 6 mounted on the carriage 64 which is returned to the reset position when printing is completed in order to prevent the ink from drying.

First of the inkjet printer head 63
In the embodiment, as shown in FIGS. 2 and 3, the head holder 1, the two head units 6 and 6 arranged in parallel on the lower surface side of the bottom plate 5, and the nozzle row on the surface of each head unit 6 are exposed. The opening windows 44a, 44a which are configured to
4b, and is constituted by the surfaces of the head units 6, 6 and a box-shaped protective cover 44 fixed to the head holder 1.

The head holder 1 in the first embodiment is
As shown in FIGS. 2 to 5, an injection-molded product of synthetic resin material such as polypropylene, polypropylene, etc.
(See 3)). In this opening,
It has a mounting portion 3 on which four ink cartridges 61 as an ink supply source can be detachably mounted from above, and the ink cartridges 6 are provided on one side of the mounting portion 3.
The ink supply passages 4a, 4b, 4c and 4d connectable to the ink discharge portion (not shown) of No. 1 are the bottom plates 5 of the head holder 1.
It is drilled so as to communicate with the lower surface of the (see Fig. 3). In addition, each ink supply passage 4a, 4b, 4c, 4d
A rubber packing (not shown) is provided on the outer periphery of the ink cartridge 61 so that the ink cartridges 61 can be brought into close contact with the ink discharge portion.
Are arranged.

The bottom plate 5 is for disposing the head unit 6, and is horizontally formed so as to project one step from the lower surface (the upper surface side in FIG. 4) of the head holder 1. On the lower surface side of the bottom plate 5, two support portions 8 for supporting two head units 6 which will be described later in parallel are formed. A plurality of adhesive pouring holes 9a, 9b for fixing the head unit 6 with the UV adhesive 7 are formed in each of the supporting portions 8 so as to penetrate toward the mounting portion 3 side. The plurality of adhesive injection holes 9a, 9
b is formed at a position where the long side portions of one head unit 6 are fixed at appropriate intervals. In the embodiment, the adhesive pouring hole 9a at a position where one side (long side) of the two supporting portions 8 and 8 adjoins each other is formed wide so as to straddle the back surfaces of the two head units 6 and 6 arranged in parallel. Has been done.

As shown in FIG. 4, the ink supply passages 4a, 4b, 4c, 4 are provided at one side of the support portions 8 as shown in FIG.
An opening 50 communicating with d is provided. A substantially annular fitting groove 46 is formed so as to surround the outer periphery of each opening 50. Then, in each of the fitting grooves 46, a ring-shaped packing 4 made of soft rubber or the like and having a good sealing property is provided.
7 is fitted.

When each head unit 6 is fixed to the lower surface of the bottom plate 5 with a UV adhesive 7 as described later, the tip of the packing 47 has an ink supply port 19a in the head unit 6 (see FIG. 12). ) Is pressed to the outer circumference,
The contact portion with the ink supply port 19a is sealed to prevent ink leakage.

Before that, first, the details of the head unit 6 and each component thereof will be described. Head unit 6
As shown in FIGS. 12 to 15, a plurality of metal plate laminated cavity plates 10 and an adhesive or an adhesive sheet 41 (FIG.
The plate type piezoelectric actuator 20 is adhered and laminated via (see 5), and the flexible flat cable 40 is superposed on the upper surface of the plate type piezoelectric actuator 20 for electrical connection with an external device.

As will be described later, the head unit 6
A filter 29 for removing dust in the ink supplied from the ink cartridge 61 above the ink supply port 19a formed on one end of the uppermost base plate 14 on the back side of the ink supply port 19a. It is fixed in advance with an adhesive (see FIGS. 12 and 13). When the cavity plate 10 is assembled to the head holder 1, the ink supply port 19a presses the periphery of the ink supply port 19a against the packing 47.

The cavity plate 10 is shown in FIG.
And as shown in FIG. That is, the nozzle plate 11, the two manifold plates 12,
It has a structure in which five thin metal plates, that is, the spacer plate 13 and the base plate 14, are stacked and joined with an adhesive, respectively, and in the embodiment, each plate except the nozzle plate 11 is made of 42% nickel alloy steel plate and has a thickness of 50 μm to 150 μm.
It has a thickness of about μm.

The nozzle plate 11 is adhered to the lower manifold plate 12, and a large number of through passages 17 communicating with the nozzles 11a are formed on both the upper and lower manifold plates 1.
2 and the spacer plate 13 are provided in a zigzag arrangement in two rows along a first direction (long side direction) at a constant pitch. Then, the two manifold plates 1
2, ink passages 12a and 12b are provided in the through hole 17
Are provided so as to extend along both sides of the row. However, the ink passage 12b in the lower manifold plate 12 is formed so as to be opened only above the manifold plate 12 (see FIG. 12).
The ink passages 12a and 12b are hermetically sealed by stacking the spacer plate 13 on the upper manifold plate 12.

The base plate 14 has a large number of narrow pressure chambers 16 extending in a second direction (short side direction) orthogonal to a center line along the long side (first direction) thereof. Has been drilled. Then, by setting parallel longitudinal reference lines 14a and 14b on both left and right sides of the center line, the tip 16a of the pressure chamber 16 on the left side of the center line is located on the right longitudinal reference line 14a. On the contrary, the tip 16a of the pressure chamber 16 on the right side of the longitudinal center line is located on the left longitudinal reference line 14b, and the left and right pressure chambers 1
Since the tips 16a of 6 are alternately arranged, the pressure chambers 16 on the left and right sides are alternately arranged so as to extend in opposite directions.

The tips 16a of the pressure chambers 16 are formed in the spacer plate 13 and the manifold plates 12 in the form of zigzag arrangements.
7 and 17 communicate with each other. On the other hand, each pressure chamber 1
The other end 16b of the nozzle 6 is provided with ink passages 12a in both manifold plates 12 through through holes 18 formed in both left and right side portions of the spacer plate 13.
It communicates with 12b. The other end 16b of each pressure chamber 16
Is the base plate 14 as shown in FIGS.
Is formed so as to open only on the lower surface side of the.

As a result, the base plate 14
Also, the ink that has flowed into the ink passages 12a and 12b from the ink supply ports 19a and 19b provided at one end of the spacer plate 13 passes through the through holes 18 from the ink passages 12a and into the pressure chambers 16. From the inside of each pressure chamber 16 to the through passages 17, 17, 1
The nozzle 11a corresponding to the pressure chamber 16 passes through 7 (see FIGS. 13 and 15).

On the other hand, the piezoelectric actuator 20 has a structure in which a plurality of piezoelectric sheets 21 are laminated as shown in FIG. 15, and as described in Japanese Patent Laid-Open No. 4-341851, each of the piezoelectric sheets 21 is Piezoelectric sheet 2 at the bottom
Narrow individual electrodes (not shown) are formed on the upper surface (wide surface) of the piezoelectric sheet 21 of 1 and the odd-numbered ones counting upward from each of the pressure chambers 16 in the cavity plate 10. There is. A common electrode (not shown) common to the plurality of pressure chambers 16 is formed on the upper surface (wide surface) of the even-numbered piezoelectric sheet 21 from the bottom. On the upper surface of the uppermost top sheet, a surface electrode 30 electrically connected to each of the individual electrodes and an electrical connection to the common electrode are formed along the edges of the long sides. The connected surface electrode 31 is provided (see FIG. 12).

The plate type piezoelectric actuator 20 having the above-mentioned structure is used in the cavity plate 1
0, the individual electrodes of the piezoelectric actuator 20 are laminated and fixed so as to correspond to the pressure chambers 16 of the cavity plate 10. Also,
On the upper surface of the piezoelectric actuator 20,
When the flexible flat cable 40 is pressed repeatedly, the flexible flat cable 40
Various wiring patterns (not shown) are electrically connected to the surface electrodes 30 and 31.

In this structure, by applying a voltage between an arbitrary individual electrode of the individual electrodes in the piezoelectric actuator 20 and the common electrode, it is possible to correspond to the individual electrode of the piezoelectric sheet to which the voltage is applied. Distortion in the stacking direction is generated due to the piezoelectric force at the portion, and the internal volume of the pressure chamber 16 corresponding to each individual electrode is reduced by this strain, so that the ink in the pressure chamber 16 is transferred to the nozzle 11
The droplets are ejected in the form of droplets (see FIG. 15), and predetermined printing is performed.

Next, the head unit 6 is attached to the head holder 1
And a photo-curable adhesive used for this fixing, for example, an uncured portion of a viscous UV adhesive 7 such as a modified acrylic resin-based adhesive as an adhesive having a quick-curing property upon irradiation with ultraviolet rays. Prevention of UV or UV adhesive 7
A means for preventing the uncured portion from diffusing and leaking to the portion of the back surface of the head unit 6 to which ultraviolet rays cannot reach will be described.

The first embodiment of the means for preventing the uncured portion of the UV adhesive 7 from diffusing and leaking to the portion of the back surface of the head unit 6 where the ultraviolet rays do not reach is the adhesive casting holes 9a and 9b. A UV adhesive from the adhesive pouring holes 9a, 9b with an elastic member interposed between the lower surface of the bottom plate 5 facing the back surface of the head unit 6 on the outer peripheral side and the back surface of the head unit 6. The head unit 6 is configured so as to be prevented from largely leaking to the back surface side of the head unit 6.

In the first embodiment, as shown in FIGS. 3 and 5, the piezoelectric actuator 20 is the back surface of the cavity plate 10 on the back surface side of each head unit 6.
The ridge body 90 made of an elastic member such as a rubber material is formed along the left and right long sides of the cavity plate 10 on the outer side. The bases of the ridges 90, 90 are fixedly erected on the back surface of the cavity plate 10 with an adhesive (not shown) such as an epoxy resin.

The two head units 6 and 6 arranged side by side and the protective cover 44 thus configured are fixed to the bottom plate 5 of the head holder 1 at the same time with the UV adhesive 7, or the protective cover is provided. 44 may be fixed later.

A method of fixing the head unit 6 to the head holder 1 will be described. As shown in FIG. 13, for example, two positioning holes 54a, 54a separated in the extension direction of the row of the nozzles 11a of the nozzle plate 11 are formed in advance.

First, the protective cover 44 is provided on the upper surface of the flat jig.
The lower plate 44b is set, and further, the two nozzle plates 11 are arranged so as to be exposed from the opening windows 44a, 44a formed in the lower plate 44b of the protective cover 44, and
Positioning holes 54a in each nozzle plate 11,
54a is fitted into a positioning pin (not shown) provided on the upper surface of the jig. In this case, it is desirable that the thickness of the lower plate 44b of the protective cover 44 be slightly thicker than that of the nozzle plate 11.

In this way, both head units 6, 6
The nozzles 11a are set so that the intervals between the rows are constant and parallel to each other. On top of them, head holder 1
The head units 6, 6 to correspond to the predetermined positions of the supporting portions 8, 8 and then the upper surface of the bottom plate 5, that is, the mounting portion 3
The UV adhesive 7 is poured from the side into the adhesive pouring holes 9a and 9b, and immediately thereafter, UV rays are irradiated from the upper surface of the bottom plate 5 toward the inside of the adhesive pouring holes 9a and 9b to rapidly cure the UV adhesive 7. Two head units 6, 6
The position of is fixed at once.

In this case, the tip (upper end) of the ridge 90 of each head unit 6 is provided with the adhesive pouring hole 9 described above.
Since it is pressed from the bottom plate 5 to the proximity portion 5a that is closer to the back surface of the cavity plate 10 than the outer circumferences a and 9b, on the back surface side of the cavity plate 10 with respect to the adhesive injection holes 9a and 9b. As a result, the long side edges of the piezoelectric actuator 20 are blocked by the proximate portion 5a and the ridges 90, and the viscous UV adhesive 7 injected into the adhesive pouring holes 9a and 9b.
It is possible to reliably prevent a large amount of diffusion / leakage that approaches the side edge side of the piezoelectric actuator 20 on the back surface side of the head unit 6. As a result, there is no place where the ultraviolet rays radiated from the upper surface side of the bottom plate 5 via the adhesive pouring holes 9a and 9b are hard to hit, and the generation of the uncured portion of the UV adhesive 7 can be prevented. Therefore, it is possible to eliminate the inconvenience that the uncured portion of the UV adhesive 7 comes into contact with the electrically conductive piezoelectric actuator 20 or the like to cause an electrical short circuit.

The front surface of each head unit 6 and the back surface of the lower plate 44b of the protective cover 44 may be preliminarily adhered and fixed with an adhesive (not shown), or only the protective cover 44 may be adhered and fixed later. May be. Further, as shown in FIG. 5, sealing agents 55a and 55b such as silicone are injected between the inner surface of the four sides of the box-shaped protective cover 44 and the stepped portion of the bottom plate 5 of the head holder 1 to seal them. The ink is prevented from entering the gap between the head unit 6 and the protective cover 44 at the time of printing or wiping by the wiper member 86.

In the second embodiment shown in FIGS. 6 to 9, the elastic members are ring bodies 91a, 91b made of elastic bodies surrounding the outer peripheral portions of the adhesive pouring holes 9a, 9b.
On the other hand, on the lower surface of the bottom plate 5, the adhesive injection holes 9 are formed.
Cylindrical portions 92a and 92b, which are the outer peripheral portions of a and 9b, are integrally formed in a protruding manner, and the ring bodies 91a and 91b are fitted in advance on the cylindrical portions 92a and 92b, respectively. Next, when the head unit 6 and the protective cover 44 are set on the jig in the same manner as in the first embodiment, the tips of the ring members 91a and 91b are attached to the back surface of the head unit 6 as shown in FIG. In the embodiment, the piezoelectric actuator 20 is pressed against and abuts against the adhesive flow-in holes 9a and 9b by the ring members 91a and 91b, so that the adhesive is injected into the adhesive flow-in holes 9a and 9b. It is possible to reliably prevent a large amount of diffusion and leakage of the viscous UV adhesive 7 that approaches the piezoelectric actuator 20 on the back surface side of the head unit 6, and the uncured portion of the UV adhesive 7 contacts the electrical element portion. That is, the same effects as those of the first embodiment, such as the prevention of the above, can be obtained. Since other configurations are substantially the same as those in the first embodiment, the same components (configurations) are designated by the same reference numerals,
Detailed description is omitted.

In the third embodiment shown in FIG. 9, on the back surface of the cavity plate 11 in each of the head units 6 and on the outer peripheral portion of the piezoelectric actuator 20 (in the embodiment, the long side edge), One or more recessed grooves 93 are formed on the outer peripheral side of the positions of the adhesive pouring holes 9a and 9b to prevent the UV adhesive 7 from flowing. The side surface external electrode 94 formed in the stacking direction (thickness direction) of the outer peripheral edge (the long side edge in the embodiment) of the piezoelectric actuator 20 has the same structure as that disclosed in JP 2001-246744 A. In addition, the individual electrodes and the common electrode inside the piezoelectric actuator 20 are electrically connected to the surface electrodes 30 and 31, and the back surface of the cavity plate 10 having conductivity such as metal and the side surface external electrode 94 are connected. So that they do not come into direct contact with each other, an insulating groove 95 is formed on the back surface of the cavity plate 10 so as to have a space with the lower end of the side surface external electrode 94.
Is formed with a recess.

On the other hand, on the lower surface of the bottom plate 5, there is formed a proximity portion 5a which protrudes downward from the vicinity of the outer peripheries of the adhesive casting holes 9a and 9b, and the rear surface of the head unit 6 (cavity plate 10 in the embodiment). Are close to each other so as to reduce the gap, and the accumulation groove 93 is arranged so as to face the proximity portion 5a. The gap between the cavity plate 10 and the adjacent portion 5a is preferably smaller than the thickness of the piezoelectric actuator 20 in order to prevent the UV adhesive 7 from approaching the piezoelectric actuator 20.

With this structure, the UV adhesive 7 having viscosity injected into the adhesive injection holes 9a and 9b is provided.
However, since it accumulates in the one or more accumulating grooves 93 in the adjacent portion 5a, a large diffusion such that the uncured portion of the UV adhesive 7 approaches the side edge of the piezoelectric actuator 20 on the back surface side of the head unit 6. Leakage can be reliably prevented, and substantially the same effect as that of the first embodiment is achieved. In addition, the pool groove 93 is provided with the adhesive pouring holes 9a, 9a.
Since it is located in the vicinity of the outer periphery of b, the UV adhesive 7 accumulated in the accumulation groove 93 is more likely to be exposed to ultraviolet rays, the curing can be promoted, and the uncured portion of the UV adhesive 7 is less likely to occur. You can Since other configurations are substantially the same as those of the first embodiment, the same components (configurations) are designated by the same reference numerals, and detailed description thereof will be omitted.

The fourth shown in FIGS. 10 (a) and 10 (b)
In the embodiment, at least the adhesive groove (concave groove) 95 for preventing the back surface of the cavity plate 10 and the side surface external electrode 94 from directly contacting each other, which is shown in the third embodiment, is used. An electric insulating material 96 is coated so as to cover all of the side surface external electrodes 94 (including the side surface of the piezoelectric actuator 20) in the portions near the outer peripheries of the agent pouring holes 9a and 9b. In the embodiment, an electrically insulating thermosetting epoxy resin adhesive including the side surface of the piezoelectric actuator 20 from the insulating groove (concave groove) 95 is included in the side surface external electrodes near the outer periphery of the adhesive pouring holes 9a and 9b. 9
It is applied so as to cover all 4 and heat-cured.

With this structure, the adhesive pouring hole 9 is formed.
The UV adhesive 7 injected from a and 9b is
Even when the side surface of the piezoelectric actuator 20 is approached from a, the side surface external electrode 94 can be electrically shielded from the UV adhesive 7 by the electric insulating material 96. what if,
If there is no electrically insulating material 96 in the insulating groove (concave groove) 95,
When the UV adhesive 7 flows into the insulating groove 95 and becomes uncured, the insulation distance between the side surface external electrode 94 of the piezoelectric actuator 20 and the conductive cavity plate 10 via the UV adhesive 7 is Insulation groove 95 depth 50 μm
Is. However, when the electric insulating material 96 is applied to the inside of the insulating groove (concave groove) 95, UV is applied onto the electric insulating material 96.
Even if the adhesive agent 7 flows in, the insulation distance between the side surface external electrode 94 and the conductive cavity plate 10 via the UV adhesive agent 7 is set to the outer edge of the side surface external electrode 94 and the insulating groove 95 (the side surface external electrode 94). From the farthest position from) 20
It can be about 0 μm. That is, even when the amount of the electrically insulating material 96 applied is small and the side surface external electrode 94 cannot be sufficiently covered, the side surface external electrode 94 is provided.
The insulation distance between the and the conductive cavity plate 10 via the UV adhesive 7 can be made sufficiently large. Further, since the gap between the cavity plate 10 and the adjacent portion 5a is sufficiently smaller than the thickness of the piezoelectric actuator 20, the UV adhesive 7 reaches the upper portion of the piezoelectric actuator 20 even if the amount of the electrically insulating material 96 applied is small. Will disappear. With these configurations, even if the uncured portion of the UV adhesive 7 approaches the side edge of the piezoelectric actuator 20, leakage of current or the like can be reliably prevented, and substantially the same effect as that of the first embodiment is achieved. Since other configurations are substantially the same as those of the first embodiment, the same components (configurations) are designated by the same reference numerals, and detailed description thereof will be omitted.

In the fifth embodiment shown in FIG. 11, a through hole 98 penetrating vertically is formed in advance in the vicinity of the side edge of the piezoelectric actuator 20 and near the adhesive pouring holes 9a, 9b. The lower end of the through hole 98 is formed so as to communicate with the insulating groove (concave groove) 95 on the back surface of the cavity plate 10.

After the head unit 6 and the head holder 1 are fixed by the UV adhesive 7 poured from the adhesive pouring holes 9a and 9b, a sealing agent 97 such as an electrically insulating silicone resin is attached to the protective cover 44 and the head holder 1. Filling between the piezoelectric actuator 20 and the flexible flat cable 40 and the head holder 1 is similar to the other embodiments, but in the case of the present embodiment, the piezoelectric actuator 20 and the flexible flat cable are filled. The sealant 97 filled between the head holder 1 and the head holder 1 is provided in the through hole 98 of the piezoelectric actuator 20 (see FIG. 11).
Through the insulating groove (concave groove) 95, and pushes up the tip of the uncured portion of the UV adhesive 7 that has been approaching the side edge of the piezoelectric actuator 20 from below, and from the side edge of the piezoelectric actuator 20. keep away. Also in this case, since the gap between the cavity plate 10 and the adjacent portion 5a is sufficiently smaller than the thickness of the piezoelectric actuator 20, the tip of the uncured portion of the UV adhesive 7 is removed from the side edge of the piezoelectric actuator 20 by the sealant 97. It becomes easier to keep away. Therefore,
It is possible to prevent the uncured portion of the UV adhesive 7 from coming into contact with an electric element portion such as the piezoelectric actuator 20, and to prevent an accident such as an electric short circuit due to ink leakage (leakage) after that. It can be reliably prevented.

Incidentally, for example, by arranging the casting holes 9a and 9b in the vicinity of the four corners of the head unit 6 having a rectangular shape in a plan view, when the UV adhesive 7 is solidified, the head unit 6 due to the contraction distortion of the adhesive is formed. It is possible to minimize the positional deviation of. Head units 6 and 6 arranged in parallel
When the casting hole 9a is formed wide across the adjacent sides of, the UV adhesive 7 is filled in one casting hole 9a, and the two units 6 and 6 are solidified at one time by ultraviolet irradiation. This can contribute to the reduction of working time and the great improvement of manufacturing efficiency. Further, the configurations of the respective embodiments exhibit more excellent effects when combined with each other.

The number of head units 6 to be arranged in parallel can be arbitrarily set to 2 to 4, and the cavity plate 10 in the head unit 6 may be made of a ceramic material instead of a metal material. Further, the driving means of the ink jet printer of the present invention may be another type of the plate-shaped piezoelectric actuator 20 described above, or the vibrating plate covering the back surface of the pressure chamber is vibrated by static electricity so that the ink is ejected from the nozzle 11a. Alternatively, it may be configured to be discharged from.

[0058]

As described above, claim 1
The invention described in (1) is an inkjet printer head in which a head unit having a plurality of nozzles arranged in a row on the front surface is fixed to a bottom plate of a head holder via a photo-curing adhesive, and the bottom plate is An adhesive casting hole is formed on the back surface of the side edge of the head unit, and an elastic member is interposed between the bottom surface of the bottom plate facing the back surface of the head unit and the back surface of the head unit. The photocurable adhesive from the adhesive pouring hole is prevented from largely leaking to the back surface side of the head unit. According to this structure, the gap between the lower surface of the bottom plate facing the back surface of the head unit and the back surface of the head unit is made into an elastic member so as to partition the gap so that the light from the adhesive pouring hole is exposed. As a result that the curable adhesive can be prevented from largely leaking to the back side of the head unit,
The distance from the adhesive pouring hole to the back side of the head unit is long, light such as ultraviolet rays irradiated from the adhesive pouring hole does not reach, even if an uncured portion occurs in the photocurable adhesive, The uncured portion can be reliably prevented from coming into contact with the conductive portion on the back surface of the head unit, and an electrical short-circuit accident during use of the head unit can be reliably eliminated.

According to a second aspect of the present invention, in the ink jet printer head according to the first aspect, the elastic member is a ring body surrounding the outer periphery of the adhesive pouring hole. In addition to the effect of the invention described in Item 1, only the outer peripheral portion of the adhesive pouring hole is surrounded by the ring body, and the effect that the usage amount of the elastic member is small can be achieved.

The invention described in claim 3 is the same as claim 1
2. The inkjet printer head according to claim 1, wherein the elastic member is a ridge that is arranged between the bottom surface of the bottom plate near the adhesive pouring hole and the back surface of the head unit. In addition to the effect according to the invention described in (1), there is an effect that the arrangement length of the ridge can be arbitrarily set to a portion having the above effect.

On the other hand, the invention according to claim 4 is an ink jet system in which a head unit having a plurality of nozzles arranged in a row on the front surface is fixed to the bottom plate of the head holder via a photo-curing adhesive. In the printer head, an adhesive pouring hole is formed in the bottom plate so as to face a back surface of a side edge portion of the head unit, and a portion of the bottom plate near an outer periphery of the adhesive pouring hole is provided on the back surface of the head unit. On the other hand, it is formed in a close portion having a small gap, and on the lower surface of the bottom plate or the back surface of the head unit in the close portion,
A reservoir groove is formed to prevent the photo-curable adhesive from the adhesive pouring hole from diffusing and leaking from the proximity portion to the back surface side of the head unit.

According to this structure, the photocurable adhesive injected from the adhesive pouring hole is temporarily accumulated in the accumulating groove, so that a large amount of diffusion leaks from the close portion having a small gap to the back surface side of the head unit having a large gap. As a result, it is possible to effectively prevent the uncured portion of the photo-curable adhesive from coming into contact with the conductive portion on the back side of the head unit, and the pool groove serves as the adhesive pouring hole. Since it is in the vicinity of the outer periphery of the photocurable adhesive, it is easy for the light curable adhesive accumulated in the accumulation groove to be exposed to light such as ultraviolet rays, which accelerates curing and causes the uncured portion of the photocurable adhesive to occur. It also has the ability to be hardened.

According to a fifth aspect of the present invention, in the ink jet printer head according to the fourth aspect, one or a plurality of recesses are formed in the reservoir groove in a direction substantially parallel to a direction in which the nozzle row extends. A plurality of conductive portions on the back surface side of the head unit are present along the direction in which the row of nozzles extends. The contact and generation of the uncured portion of the adhesive can be effectively prevented.

Further, according to a sixth aspect of the present invention, an ink jet is formed by fixing a head unit having a plurality of nozzles arranged in a row in a front surface on a bottom plate of a head holder via a photo-curing adhesive. In the printer head, an adhesive pouring hole is formed in the bottom plate so as to face a back surface of a side edge portion of the head unit, and a portion of the bottom plate near an outer periphery of the adhesive pouring hole is provided on the back surface of the head unit. On the other hand, the external electrodes on the side surface of the piezoelectric actuator are arranged along the concave groove provided on the back surface side of the head unit while being formed in the adjacent portion having a small gap, and the external electrode and the concave groove are formed. It is covered with an electrically insulating material.

With this structure, even when the photo-curing adhesive injected from the adhesive pouring hole approaches the side surface of the piezoelectric actuator from the proximity portion, the side insulating film is electrically connected to the side surface external electrode by the electrically insulating material. Can be shut off.

Further, even if the amount of the electric insulating material applied to the side surface external electrodes and the like is small, the electric insulating material is present in the concave groove, so that the uncured portion of the photocurable adhesive is the width of the piezoelectric actuator. Even if it approaches the side edge in the direction, there is an effect that leakage of current and the like can be surely prevented and an electric short circuit accident can be surely eliminated.

Further, the invention according to claim 7 is the ink jet printer head according to claim 6, wherein the piezoelectric actuator is provided with a through hole communicating from the lower surface of the bottom plate toward the concave groove. However, the electrically insulating material is a sealing agent such as silicone that fills the lower surface of the bottom plate, the through hole, and the groove.

According to the present invention, the sealing agent injected to cover the back surface of the piezoelectric actuator flows into the groove through the through hole and approaches the side edge of the piezoelectric actuator. The photocurable adhesive can be kept away. Therefore, it is possible to prevent the occurrence of an accident such as an electrical short circuit due to the uncured portion of the photo-curable adhesive agent in advance and surely.

According to an eighth aspect of the present invention, in the ink jet printer head according to any of the first to seventh aspects, a protective cover having an opening window surrounding the nozzle row of the head unit is provided in the head unit. Since the head unit and the protective cover are arranged on the front surface and are fixed by the photo-curable adhesive, in addition to the effects of the invention according to claims 1 to 7, the head is attached to the bottom plate of the head holder. The effect that the unit and the protective cover can be fixed at the same time is achieved.

[Brief description of drawings]

FIG. 1 is a perspective view of an inkjet printer to which the present invention is applied.

FIG. 2 is a perspective view of the inkjet printer head with the nozzle side facing upward.

FIG. 3 is an exploded perspective view of components of the inkjet printer head according to the first embodiment.

FIG. 4 is an exploded perspective view of components of the inkjet printer head as seen from above the head holder in the first embodiment.

FIG. 5 is a side sectional view of an essential part of the first embodiment.

FIG. 6 is an exploded perspective view of components of an inkjet printer head as seen from above a head holder according to a second embodiment.

FIG. 7 is an enlarged plan view of an essential part in the second embodiment.

FIG. 8 is a side sectional view of an essential part in the second embodiment.

FIG. 9 is an enlarged side sectional view of an essential part in the third embodiment.

FIG. 10A is a side sectional view of an essential part in the fourth embodiment, and FIG. 10B is a further enlarged side sectional view.

FIG. 11 is an enlarged side sectional view of an essential part in the fifth embodiment.

FIG. 12 is a perspective view of each component of the head unit.

FIG. 13 is a perspective view of each component of the cavity plate.

FIG. 14 is a partially enlarged perspective view of a cavity plate.

FIG. 15 is an enlarged side sectional view of a head unit.

[Explanation of symbols]

1 head holder 5 bottom plate 5a Proximity part 6 head unit 7 UV adhesive 8 Support 9a, 9b Adhesive pouring hole 10 cavity plate 11 nozzle plate 11a nozzle 20 Piezoelectric actuator 40 flexible cable 44 Protective cover 44a open window 90 ridges 91a, 91b Ring body 92a, 92b Cylindrical part 93 Reservoir groove 95 concave groove (insulation groove) 96 Electrical insulating material 97 Sealant

Claims (8)

[Claims] 1. An ink jet printer head comprising a head unit having a plurality of nozzles arranged in a row on the front surface and fixed to a bottom plate of a head holder via a photo-curing adhesive. Adhesive pouring holes are formed on the back surface of the side edge portion of the head unit, and an elastic member is interposed between the bottom surface of the bottom plate facing the back surface of the head unit and the back surface of the head unit. An ink jet printer head, characterized in that it is configured to prevent the photo-curable adhesive from the adhesive pouring hole from largely leaking to the back surface side of the head unit. 2. The ink jet printer head according to claim 1, wherein the elastic member is a ring body that surrounds the outer periphery of the adhesive pouring hole. 3. The elastic member is a ridge that is arranged between the lower surface of the bottom plate near the adhesive pouring hole and the back surface of the head unit.
The inkjet printer head according to item 1. 4. An ink jet printer head, comprising a head unit having a plurality of nozzles arranged in a row on the front surface, which is fixed to a bottom plate of a head holder via a photo-curing adhesive. An adhesive pouring hole is formed opposite to the back surface of the side edge portion of the head unit, and a portion of the bottom plate near the outer periphery of the adhesive pouring hole is formed in a close portion with a small gap with respect to the back surface of the head unit. However, on the lower surface of the bottom plate or the back surface of the head unit in the proximity portion, in order to prevent the photo-curable adhesive from the adhesive casting hole from diffusing and leaking from the proximity portion to the back surface side of the head unit. An ink jet printer head characterized in that a reservoir groove is formed. 5. The ink jet printer head according to claim 4, wherein the reservoir groove is formed in one or a plurality of recesses substantially parallel to a direction in which the nozzle row extends. 6. An ink jet printer head, comprising a head unit having a plurality of nozzles arranged in a row on the front surface and fixed to a bottom plate of a head holder via a photo-curing adhesive. An adhesive pouring hole is formed opposite to the back surface of the side edge portion of the head unit, and a portion of the bottom plate near the outer periphery of the adhesive pouring hole is formed in a close portion with a small gap with respect to the back surface of the head unit. On the other hand, the external electrode on the side surface of the piezoelectric actuator is arranged along the concave groove provided on the back surface side of the head unit, and the external electrode and the concave groove are made of an electrically insulating material. An inkjet printer head characterized by being coated. 7. The piezoelectric actuator is provided with a through hole communicating from the lower surface direction of the bottom plate toward the groove, and the electrically insulating material is formed on the lower surface of the bottom plate, the through hole and the groove. The ink jet printer head according to claim 6, wherein the ink is a sealant such as silicone filling the ink. 8. A protective cover having an opening window surrounding the nozzle row of the head unit is arranged on the front surface of the head unit, and the head unit and the protective cover are fixed by the photo-curing adhesive. An ink jet printer head according to any one of claims 1 to 7, characterized in that: