JPH1058681A - Ink jet recording head - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a side shoot type ink jet recording head in which the characteristics are enhanced while suppressing fluctuation by bonding a plurality of thin plate through an adhesive. SOLUTION: A lower plate 41 comprising a thin plate having ink nozzles and protrusions 42 is bonded to an intermediate plate 31 comprising a thin plate having nozzle channels, an ink sump 7 and protrusions 32 through an adhesive layer 43 having thickness determined by the protrusions 42. An upper plate 20 comprising a thin plate having an ink pressurization chamber is bonded onto the intermediate plate 31 through an adhesive layer 33 having thickness determined by the protrusions 32 and a piezoelectric element 9 is bonded by an adhesive layer 10 to the upper surface of the upper plate 20 facing the ink pressurization chamber. The protrusions are arranged at a plurality of positions on the periphery of the ink channel and the thickness of the adhesive layers 33, 43 is controlled by the protrusions 32, 42 such that the adhesive is prevented from being spread into the ink channel.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording head mounted on a recorder or a printer widely used for industrial or consumer use.

[0002]

2. Description of the Related Art A method of ejecting ink from fine nozzle holes and attaching the ink onto a recording medium such as paper for recording is known as an ink jet recording method. One of such methods is an on-demand type ink jet recording head. Ink jet recording heads of this type are generally classified into two types, a side shoot type shown in FIG. 5 and an edge shoot type shown in FIG.

[0003] As shown in FIG.
An upper plate 20 in which a plurality of ink pressurizing chambers 4 are formed on a ceramic plate, a glass plate, a metal plate, a plastic plate, or the like by a method such as etching, machining, molding, or the like. An intermediate plate 30 in which a plurality of nozzle flow paths 3 corresponding to the ink pressurizing chambers 4 are formed.
And a lower plate 40 on which a plurality of ink nozzles 2 corresponding to the nozzle flow paths 3 are formed.
A piezoelectric element 9, which is an electromechanical conversion element, is bonded to an outer surface of the surface 20 facing the ink pressurizing chamber 4 by an adhesive layer 10.

[0004] The edge shoot type, as shown in FIG.
An ink nozzle 2, a nozzle flow path 3, an ink pressurizing chamber 4, an ink supply path 5, A plurality of ink channels 11 composed of the throttle channels 6 and a common ink reservoir 7
And a groove for forming the ink inlet 12 is formed.
A vibration plate 8 is laminated and integrated on the groove-side surface of the flow path substrate 1, and a piezoelectric element 9 is provided with an adhesive at a position facing the ink pressurizing chamber 4 on the outer surface of the vibration plate 8. They are joined by a layer 10. FIG. 6 is a pattern diagram showing an example of a flow path pattern of the flow path substrate 1.

In such a structure, when a voltage pulse is applied to the piezoelectric element 9, the upper plate 20
Alternatively, the vibration plate 8 is displaced toward the ink pressurizing chamber 4 to rapidly reduce the volume of the ink pressurizing chamber 4, and the ink corresponding to the change in volume is ejected from the ink nozzle 2 and becomes an ink droplet. Is printed and recorded on the recording paper. Depending on the material to be used, electrostatic bonding, diffusion bonding, thermocompression bonding, heat fusion bonding, solvent bonding, or bonding with an adhesive, etc., are used as the bonding technology of lamination / integration for forming the above structure. I have.

[0006]

Among the joining methods described in the section of the prior art, a method that does not select the kind of joining material is joining by an adhesive. In the case of using this method, in an edge chute type structure as shown in FIG. 7, the nozzle portion is processed to a predetermined length by mechanical processing such as polishing after bonding, but the bonding surface is peeled off in this processing. There is a problem, and further, the adhesive protrudes into a fine channel portion such as the ink nozzle 2 to change the shape of the channel,
There is a problem that it is blocked.

On the other hand, in the structure of the side chute type as shown in FIG. 5, since it is not necessary to perform machining or the like after joining, joining with an adhesive can be adopted. There is a problem that it runs off like the edge shoot type. The present invention solves the above-described side chute type ink jet recording head by eliminating the protrusion of the adhesive in the flow path at the time of bonding the adhesive in the side chute type structure, and by using the adhesive bonding with less limitation of the material used. It is an object to realize an ink jet recording head having excellent characteristics.

[0008]

In order to solve the above-mentioned problems, according to the present invention, a plurality of projections are formed in a region of a thin plate to be joined with an adhesive so as to surround a portion for forming a flow path. ing. Since the thickness of the adhesive layer can be controlled by the convex portions, it is possible to prevent the adhesive from protruding into the flow path so as to adversely affect the characteristics.

This projection can be formed by etching a thin plate, or can be formed by using an adhesive. Further, it is effective to provide a region having no adhesive layer in the periphery of the convex portion. To ensure reliable bonding, the thickness of the printed adhesive is somewhat thicker than the bonding layer at the time of bonding. This is because it functions as a region for absorbing the adhesive.

[0010] At least the thin plate on which the ink nozzles are formed is excellent in metal. This is because metal is most suitable for forming fine through-holes such as ink nozzles and for forming projections.

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of an ink jet recording head according to the present invention will be described with reference to FIGS. 1 and 2 are conceptual cross-sectional views of an ink jet recording head. FIG. 1 is a cross-sectional view passing through a convex portion, and FIG. 2 is a cross-sectional view passing through an ink pressurizing chamber. FIG. 3 is a conceptual cross-sectional view showing a cross section on the middle plate side in an adhesive layer portion joining the upper plate and the middle plate,
FIG. 4 is a conceptual cross-sectional view showing a cross section on the lower plate side in an adhesive layer portion joining the middle plate and the lower plate. In the figure, portions having the same functions as those of the conventional technology are denoted by the same reference numerals.

An ink jet recording head according to the present invention is a lower plate made of a thin plate having an ink nozzle 2 and a convex portion 42.
An intermediate plate 31 made of a thin plate having a nozzle channel 3, an ink reservoir 7, and a convex portion 32 is provided with an adhesive layer 43 having a thickness determined by the convex portion 42.
The upper plate 20 made of a thin plate having the ink pressurizing chamber 4 is joined on the middle plate 31 with an adhesive layer 33 having a thickness determined by the convex portion 32. The piezoelectric element 9 is joined to the opposing upper surface by an adhesive layer 10. here,
Although the case where the convex portions 42 and 43 are formed on the lower plate 41 and the middle plate 31 has been described, the same effect can be obtained by forming the convex portions on any two plates such as the upper plate 20 and the middle plate 31. it can.

As shown in FIG. 3 and FIG.
Are ink nozzles 2 and nozzle flow paths 3, which are ink flow paths,
It is arranged so as to surround the ink pressurizing chamber 4 and the ink reservoir 7. The adhesive layers 33 and 43 are printed except for the peripheral portions of the protrusions 32 and 42, the portions corresponding to the ink pressurizing chamber 4 and the ink reservoir 7, and the like. The projections 32 and 42 that determine the thickness of the adhesive layers 33 and 43 are 1 to 100 μm in height. The method of forming the thin layers is etching of a thin plate, screen printing of an adhesive on the thin plate, or a dispenser. There are methods such as adhesive application. As the adhesive for forming the convex portion, an ultraviolet curing type, an ultraviolet and heat combined type, a thermosetting type, or the like can be used. The thickness is adjusted according to the height of the projection, and is somewhat thicker than the height of the projection to ensure bonding. The upper plate 20, the middle plate 31, and the lower plate 41 have a thickness of 10 to
200 μm metals such as nickel and stainless steel (SUS304), ceramics such as zirconia and alumina, and resins such as polyetherimide, polyethersulfone and polyarylate are used. If the upper plate 20 does not have conductivity, it is necessary to form a conductive layer on the surface of the piezoelectric element 9 before joining it. As a method for forming the conductive layer, screen printing of a conductive paste, vapor deposition of metal or ITO, or sputtering is used.

As a manufacturing method, the projections 32 or 42 necessary for the thin plates serving as the upper plate 20, the middle plate 31, and the lower plate 41 and a portion corresponding to the ink flow path are formed, and the adhesive layer 33 is formed on the corresponding thin plates.
Alternatively, 43 is formed by roller coating, screen printing, or the like, and when it is necessary to temporarily cure the adhesive layer 33 or 43, these adhesive sheets are temporarily cured,
Pressure is applied under a load of 〜10 kg / cm ² , and the used adhesive is cured under predetermined curing conditions and integrated to obtain an ink jet recording head.

An embodiment will be described below. [First Embodiment] As a material of the middle plate 31 and the lower plate 41,
Using a 120 μm nickel thin plate, a hole corresponding to the nozzle flow path 3 and the ink reservoir 7 is formed in the middle plate 31, and a hole corresponding to the ink nozzle 2 is formed in the lower plate 41 by etching. The protrusions 32 or 42 having a height of 20 μm were formed. The upper plate 20 was made of a thin nickel plate having a thickness of 110 μm, and was etched so that the thickness of the ink pressurizing chamber 4 became 20 μm. Next, the layers serving as the adhesive layers 33 and 43 are screen-printed on the lower surfaces of the upper plate 20 and the middle plate 31 so that the thermoplastic adhesive (371 manufactured by Techno Alpha Co., Ltd.) has a thickness of 21 μm after drying. It was applied and dried under predetermined conditions.
Thereafter, the upper plate 20, the middle plate 31, and the lower plate 41 were overlapped, pressed under a load of 5 kg / cm ² , heated at 170 ° C. for 10 minutes, and bonded to be integrated. Finally, a PZT-based piezoelectric element 9 having a thickness of 20 μm was bonded to the upper surface of the upper plate 20 at a position facing the ink pressurizing chamber with an epoxy-based adhesive layer 10 to complete an ink jet recording head.

The ink ejection characteristics and the thickness of the adhesive layers 33 and 43 of the ink jet recording head prepared as described above are as follows: average ink ejection speed: 9 m / sec; ink ejection speed deviation: ± 8% adhesive layers 33 and 43 Thickness: 19 to 20 μm.

[Second Embodiment] A nickel thin plate having a thickness of 100 μm is used as a material of the middle plate 31 and the lower plate 41, and holes corresponding to the nozzle flow path 3 and the ink reservoir 7 are formed in the middle plate 31 by an excimer laser. In the lower plate 41, holes corresponding to the ink nozzles 2 are formed by etching, and a photo-curable adhesive (3042D manufactured by Three Bond Co.) is screen-printed on one side of the lower plate 41 to a height of 20 μm after being cured by screen printing. The protrusions 32 or 42 were formed by coating as needed. The thickness of the upper plate 20
A 110μm zirconia thin plate is used as the material, and the ink pressurizing chamber 4
Processing was performed by laser processing using an excimer laser so that the thickness of the portion became 20 μm. Since the material is an insulating material, electrodes for applying a voltage to the piezoelectric element 9 were formed by screen-printing a platinum paste. Next, the layers to be the adhesive layers 33 and 43 are applied to the upper plate 20 and the middle plate 31 by screen printing so that the thermoplastic adhesive (371 manufactured by Techno Alpha Co., Ltd.) becomes 21 μm in thickness after drying. And dried under predetermined conditions. Thereafter, the upper plate 20, the middle plate 31, and the lower plate 41 are overlapped,
It was pressurized with a load of 5 kg / cm ² and heated at 170 ° C. for 10 minutes to bond and integrate. Finally, the thickness of the epoxy adhesive layer 10
A 20 μm PZT-based piezoelectric element 9 was bonded to the upper surface of the upper plate 20 at a position facing the ink pressurizing chamber to complete an ink jet recording head.

The ink ejection characteristics and the thickness of the adhesive layers 33 and 43 of the ink jet recording head thus prepared are as follows: average ink ejection speed: 8 m / sec. Ink ejection speed deviation: ± 10%. Thickness: 19 to 20 μm.

[Third Embodiment] As a material of the middle plate 31 and the lower plate 41, a nickel thin plate having a thickness of 100 μm is used. In the middle plate 31, holes corresponding to the nozzle flow path 3 and the ink reservoir 7 are provided. Board
A hole corresponding to the ink nozzle 2 is formed by punching out a hole corresponding to the ink nozzle 2 on 41, and a light-curable adhesive (3042D manufactured by Three Bond Co.) is screen-printed on one side of the hole to a height of 20 after being cured by screen printing.
The protrusions 32 or 42 were formed by coating to a thickness of μm. The upper plate 20 was made of an alumina thin plate having a thickness of 110 μm, and was processed by laser processing using an excimer laser so that the thickness of the ink pressurizing chamber 4 became 20 μm. Also in this case, since the material is an insulating material, the electrodes for applying a voltage to the piezoelectric element 9 were formed by screen printing a platinum paste. Next, the layers to be the adhesive layers 33 and 43 are formed on the upper plate 20 and the middle plate 31 by using a hot-melt adhesive (HM-245 manufactured by Cemedine).
Was applied by screen printing so that the thickness after drying was 21 μm, and dried under predetermined conditions. Thereafter, the upper plate 20, the middle plate 31, and the lower plate 41 were overlapped, pressed under a load of 5 kg / cm ² , heated at 150 ° C. for 10 minutes, and bonded and integrated.
Finally, a 20 μm thick PZT with an epoxy-based adhesive layer 10
Plate 20 at a position facing the ink pressurizing chamber.
To form an ink jet recording head.

The ink ejection characteristics and the thickness of the adhesive layers 33 and 43 of the ink jet recording head thus prepared are as follows: average ink ejection speed: 9 m / sec. Ink ejection speed deviation: ± 12%. Thickness: 18-20 μm.

For reference, the ink ejection characteristics and the ink discharge characteristics in the case of an ink jet recording head formed by using the same material as in the first embodiment and using an adhesive layer of 21 μm in a state where no convex portion is formed, that is, in the state of the art. Adhesive layer 33 and
The thickness of 43 was as follows: average ink ejection speed: 4 m / sec. Ink ejection speed deviation: ± 50%. Thickness of the adhesive layers 33 and 43: 1 to 10 μm.

Thus, by providing the convex portions, the thicknesses of the adhesive layers 33 and 43 are made uniform, the adhesive does not protrude into the ink flow path, and good ink ejection characteristics are obtained.

[0023]

According to the present invention, a plurality of projections are provided in a region joined by the adhesive layer, and the thickness of the adhesive layer is controlled by the height of the projections. The thickness of the ink is accurately determined, the adhesive does not protrude into the ink flow path, and the ink ejection characteristics are not deteriorated.
An ink jet recording head with less variation in characteristics and therefore good print quality can be stably produced.

[Brief description of the drawings]

FIG. 1 is a sectional view showing the structure of an ink jet recording head according to the present invention.

FIG. 2 is a sectional view of another part showing the structure of the ink jet recording head according to the present invention.

FIG. 3 is a conceptual cross-sectional view showing a cross section on the middle plate side in an adhesive layer portion joining the upper plate and the middle plate of the inkjet recording head according to the present invention.

FIG. 4 is a conceptual cross-sectional view showing a cross section on the lower plate side in the adhesive layer portion joining the middle plate and the lower plate of the inkjet recording head according to the present invention.

FIG. 5 is a conceptual sectional view showing the structure of a conventional side chute type ink jet recording head.

FIG. 6 is a pattern diagram of an example of a flow path substrate of a conventional edge shoot type ink jet recording head.

FIG. 7 is a conceptual sectional view showing the structure of a conventional edge chute type ink jet recording head.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 flow path substrate 2 ink nozzle 3 nozzle flow path 4 ink pressurization chamber 5 ink supply path 6 throttle path 7 ink reservoir 8 vibrating plate 9 piezoelectric element 10 adhesive layer 11 ink flow path 12 ink inlet 20 upper plate 30, 31 Middle plate 32 Convex part 33 Adhesive layer 40, 41 Lower plate 42 Convex part 43 Adhesive layer

Claims (5)

[Claims] 1. An ink jet apparatus comprising: a plurality of thin plates joined by an adhesive forming a part of an ink flow path including an ink pressurizing chamber; and a thin plate having an ink nozzle having an ink nozzle formed as a through hole. An ink jet recording head, wherein a plurality of projections are formed in a region of a thin plate joined with an adhesive so as to surround a portion forming a flow path. 2. The ink jet recording head according to claim 1, wherein the projection is a projection formed by etching a thin plate. 3. The ink jet recording head according to claim 1, wherein the projection is a projection formed of an adhesive. 4. The ink jet recording head according to claim 1, wherein there is a region without an adhesive layer around the convex portion. 5. The apparatus according to claim 1, wherein at least the thin plate on which the ink nozzles are formed is made of metal.
The inkjet recording head according to any one of the above.