JP3374893B2 - Ink jet recording head - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ink jet recording head using a piezoelectric vibrator in a longitudinal vibration mode as a driving source, and more particularly, to an ink jet recording head which receives expansion and contraction of a piezoelectric vibrator. contracting the pressure generating chambers Te relates to structure of the elastic plate inflating. 2. Description of the Related Art In order to improve the recording density of a recording head, the pitch of nozzle rows tends to be small. Therefore, a silicon single crystal wafer is anisotropically etched.
A nozzle plate or an elastic plate manufactured by another method is fixed with an adhesive to form a flow path unit, and the displacement of the piezoelectric vibrator is transmitted thereto to generate pressure in the pressure generation chamber. Is configured to eject ink droplets from the nozzle openings. [0003] When the arrangement density of the pressure generating chambers is increased as described above, the width of the pressure generating chambers becomes extremely small. Therefore, it is necessary to efficiently deform the entire length of the pressure generating chambers. A convex portion extending in the longitudinal direction of the generation chamber, that is, an island portion is formed, and the displacement of the piezoelectric vibrator is transmitted to the elastic plate via the island portion. As such an elastic plate, a layer of a polymer material is formed on one surface of a thin metal plate by a dipping method, a roll coating method, a spraying method, or the like, and the thin metal plate is etched to form an island portion. A method in which a polymer material layer formed and exposed by etching is used as a diaphragm has been proposed (WO93 / 25390). A tip of a piezoelectric vibrator of a longitudinal vibration mode extending in the axial direction is brought into contact with the island portion of the elastic plate thus configured, and is fixed by an adhesive to constitute an ink jet recording head. . At this time, there is a problem that the adhesive flows into the diaphragm and changes the rigidity of the diaphragm to change the ink droplet ejection performance. In order to solve such a problem, the height of the island portion is made as high as possible so that the adhesive is absorbed on the side wall of the island portion.
There is a problem that the bottom portion in contact with the diaphragm becomes unnecessarily wide, and the high-density arrangement becomes difficult, the etching time becomes long, and the etching accuracy decreases. The present invention has been made in view of such a problem, and an object of the present invention is to prevent an adhesive used for fixing to a piezoelectric vibrator from flowing out, and to increase the height of an island portion as much as possible. An object of the present invention is to provide an ink jet recording head which can be lowered. According to the present invention, a nozzle plate having a nozzle opening, a pressure generating chamber, an ink supply port, and a reservoir are formed. A flow path unit formed by joining a spacer and an elastic plate having an island portion opposed to the pressure generating chamber, and a piezoelectric vibrator in a longitudinal vibration mode for abutting on the island portion to eject ink droplets. In the ink jet recording head comprising :
An etching protection film is formed on the elastic plate for etching.
The width of the tip is narrower than the width of the bottom, and
The etching protection film overhangs the tip of the land portion . When the adhesive for fixing the piezoelectric vibrator and the island portion tries to overflow to the outside, the adhesive is received by a film having an area larger than that of the island portion provided so as to overhang from the island portion, and the bottom portion is prevented. Movement to is blocked. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to the illustrated embodiments. 1 and 2 show one embodiment of an ink jet recording head according to the present invention. In the drawings, reference numeral 1 denotes a nozzle plate having nozzle openings 2, 2, 2. Is a member that partitions the pressure generating chamber 4, the ink supply port 5, and the reservoir 6. Reference numeral 7 denotes an elastic plate characterized by the present invention.
As shown in the figure, a rigid and etchable material such as a metal, for example, a metal thin plate 9 is laminated on the surface of a stretched polymer film 8 via an adhesive layer 10 on the surface of the stretched polymer film 8. The nozzle plate 1 is formed by etching to form a diaphragm portion 11 and an island portion 12.
The elastic plate 7 is joined to the spacer member 3 with an adhesive so as to seal both surfaces of the spacer member 3, thereby forming a flow path unit 13. Reference numeral 14 in the figure denotes a vibrator unit.
As shown in (1), the electrode 15 serving as one pole and the electrode 16 serving as the other pole are laminated in a sandwich manner via a piezoelectric material 17, one electrode 15 is disposed on the tip side, and the other electrode 1 is disposed. 6 is exposed to the rear end side, and the piezoelectric vibrator 20 connected to the segment electrode 18 and the common electrode 19 at each end face is
The piezoelectric vibrators 20 are fixed to the head frame 23 via the fixing plate 22 with the tips of the piezoelectric vibrators 20 abutting on the island portions 12. In this embodiment, the elastic plate 7
As described above, the adhesive 10 is applied to one surface of a thin metal plate having a durability of 20 μm with respect to ink, for example, a stainless steel plate 9, and after the adhesive 10 is pre-dried, the thickness is 4 μm. The polymer stretched film 8 having a thickness of, for example, a laminated material obtained by bonding a stretched film of polyphenylene sulfide (PPS) resin is etched because the metal thin stainless steel plate 9 is etched so as to form the island portion 12. Thickness used during etching 1
It is configured such that the photosensitive resin film 24 of 0 to 40 μm is left as one member constituting the island portion 12 without being removed. That is, an adhesive 10 is applied to one surface of a thin metal plate, for example, a stainless steel plate 9 having a thickness of 20 μm, which is durable with respect to ink, and after the adhesive is pre-dried, the thickness is about 4 μm. A laminated material 25 is formed by bonding a stretched polymer film 8 of, for example, a stretched film of polyphenylene sulfide (PPS) resin (FIG. 6).
(I)). The laminated material 25 is cut into a required size to cut out a large size, a hole serving as a reference for etching pattern exposure, a reference hole for positioning when setting in a press, and a single elastic material cut from the large size. A reference hole for positioning as the plate 7 and a through-hole such as a hole serving as an ink supply port are formed in advance by press working. Next, the stainless steel plate 9 of the laminated material 25 is set on a glass substrate so that the surface thereof is exposed, and a photosensitive resin film 24 is attached to the surface of the stainless steel plate 9.
Desirably, the entire laminate material 25 is fixed to the substrate with the photosensitive resin film 24 (FIG. 6 (II)). In this state, the photosensitive resin film 24 is exposed using a mask on which a pattern to be etched is formed, leaving the photosensitive resin film 24 in a region to be the island portion 12 and penetrating the diaphragm portion 11. An etching protection film to be a hole is formed (FIG. 6 (III)). Next, when the laminate 25 is etched using the etching protection film, the stainless steel plate 9 is etched.
Is gradually removed from the surface and becomes thin (FIG. 6 (IV)).
When the etching proceeds in this manner, the etching proceeds not only in the thickness direction of the stainless steel plate 9 but also in the horizontal direction. Therefore, the stainless steel plate 9 on the back surface 24a of the photosensitive resin film 24 functioning as an etching protection film.
Is also etched, so that the photosensitive resin film 24 is exposed like an eave (FIG. 6 (V)). When the etching further proceeds, the adhesive layer 1
Since 0 is exposed and etching in the thickness direction of the stainless steel plate 9 is stopped, the etching is terminated. Thereby, a thin portion composed of the adhesive layer 10 and the stretched polymer film 8,
That is, the island portion 12 surrounded by the diaphragm portion 11
Is formed. At the stage where the etching is completed, the back surface 24a of the photosensitive resin film 24 is also considerably etched, and the island portion 12 is formed in a trapezoidal cross section (FIG. 6 (VI)). The flow path unit 13 having the elastic plate 7 thus configured is fixed to the fixing portion 25 of the head frame 23, and the head frame 23 is set again so that the flow path unit 13 is at a lower position. An adhesive P is applied to the tip of the piezoelectric vibrator 20 of the vibrator unit 14 to which a flexible cable (not shown) is connected, so that the head frame 2
When the piezoelectric vibrator unit 14 is dropped from the opening 26 of the third plate 3, the tip of the piezoelectric vibrator 20 is bonded to the island portion 12 of the elastic plate 7 constituting the flow path unit 13 as shown in FIG. The contact is made via the agent P. At this time, the adhesive P applied to the piezoelectric vibrator 20 tends to overflow due to the pressure of the island portion 12 and the piezoelectric vibrator 20, but most of the adhesive P1 is , The island portion 1 as shown in FIG.
2 functions as a protective film for etching,
The surface area of the photosensitive resin film 24 which has a size larger than that of the surface of the photosensitive resin film 24 is received by the large surface area and is prevented from moving to the island portion 12. Also, for example, the adhesive P2 that cannot be absorbed on the surface of the photosensitive resin film 24 flows into the gap between the photosensitive resin film 24 and the island portion 12, and is held by the capillary force and solidified. As a result, it is prevented from flowing out to the diaphragm 11. As described above, since the flow of the adhesive for fixing the piezoelectric vibrator 20 and the island portion 12 can be completely prevented from flowing out to the diaphragm portion 11 by the photosensitive resin film 24, the height H of the island portion 12 can be prevented. (FIG. 5
It is necessary to allow (b)) a value as small as possible so that the displacement of the piezoelectric vibrator 20 can be transmitted to the pressure generating chamber 4, that is, allowance for preventing the flow of the adhesive P to the diaphragm portion 11. Since there is no such material, a material having a thickness of 20 μm or less can be used, and the difference between the width W1 at the tip of the island portion and the width W2 at the bottom can be made as small as possible.
The island portion is formed with an ideal shape or with high precision, thereby making it possible to increase the density of the recording head. At the stage where the fixing of the vibrator unit 14 is completed in this way, a metal frame 27 also serving as a shield plate is put on the flow path unit 13 side and fixed to the head frame 23 to complete the ink jet recording head. I do. In the above embodiment, stainless steel is used as the metal thin plate. However, another metal which can be etched and has high adhesiveness, for example, a thin plate of copper, nickel, iron or silicon is used. Can be used. Although a polyphenylene sulfide (PPS) resin is used as the polymer stretched film, other polymer materials that can be stretched, for example, polyimide (PI)
Resin, polyether imide (PEI) resin, polyamide imide (PAI) resin, polybalavanic acid (PPA) resin, polysulfone (PSF) resin, polyether sulfone (PES) resin resin, polyether ketone (PEK)
Resin, polyetheretherketone (PEEK) resin,
Polyolefin (APO) resin, polyethylene naphthalate (PEN) resin, aramid resin, polypropylene resin, vinylidene chloride resin, polycarbonate resin and the like can also be used. As described above, according to the present invention ,
Even if the adhesive for fixing the piezoelectric vibrator and the island part overflows to the outside, the large area of the film provided so as to overhang from the island part can catch and prevent it, and the metal as thin as possible By using a plate to form an island portion with an ideal shape or with high accuracy, it is possible to increase the density of the recording head.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an assembled perspective view showing one embodiment of an ink jet recording head of the present invention. FIG. 2 is a diagram showing one embodiment of an ink jet recording head of the present invention in a longitudinal section of a pressure generating chamber. FIG. 3 is a top view showing one embodiment of the elastic plate. FIGS. 4A and 4B are a perspective view and a cross-sectional view, respectively, showing one embodiment of a vibrator unit. FIGS. 5A and 5B are enlarged views of one embodiment of the ink jet recording head of the present invention, showing a cross section in the direction in which the pressure generating chambers are arranged and one island portion. . FIGS. 6 (I) to (VI) are diagrams showing steps of manufacturing the elastic plate, respectively. [Description of Signs] 1 Nozzle plate 3 Spacer 4 Pressure generating chamber 5 Ink supply port 6 Reservoir 7 Elastic plate 8 Polymer stretched film 9 Metal plate 10 Adhesive layer 11 Diaphragm part 12 Island part 13 Flow path unit 14 Piezoelectric vibration unit 20 Piezoelectric vibrator P, P1, P2 Adhesive 24 Photosensitive resin film

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B41J 2/045 B41J 2/055 B41J 2/16

Claims (1)

(1) A nozzle plate having a nozzle opening, a spacer forming a pressure generating chamber, an ink supply port, and a reservoir, and an island portion facing the pressure generating chamber. An ink jet recording head comprising a flow path unit formed by bonding an elastic plate having a shape and a piezoelectric vibrator in a longitudinal vibration mode in which an ink droplet is ejected in contact with the island portion. An ink jet recording head, wherein an etching protection film is formed on the elastic plate, the width of the tip is narrower than the width of the bottom by etching, and the etching protection film is overhanging at the tip of the island portion.