JPH0414457A - Recording head - Google Patents

Abstract

PURPOSE:To permit a simultaneous heating of an ink in a plurality of directions and an efficient formation of bubbles by a method wherein a plurality of inclined surfaces are formed on a Si single crystal by an anisotropic etching and heat producing parts are provided on the inclined surfaces. CONSTITUTION:Si single crystal 100 is worked by an anisotropic etching into a V-shaped structure having flat faces at its top part. Each of a plurality of the inclined surfaces for defining grooves indicated in numerical order starting with 101 is provided with a heat producing part. A plate 400 is attached to the V-shaped structure with each section thereof facing the corresponding heat producing parts and an ink is fed into the aforesaid grooves so as to be heated therein. To form the plate 400, polyimide membrane, glass resin, glass and processed Si with the surface insulated are used. When the heat producing part is set at a nozzle part, each of electrodes 311-316 is connected electrically with a corresponding one of electrodes 301-306. This structure permits an easy electric connection with the exterior and an efficient discharge of the ink from nozzles 511-515.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a recording head for performing dot printing in an inkjet printer.

(Prior Art) Conventionally, various methods have been provided for operating a recording head in an inkjet printer, but a method in which bubbles are generated using Joule heat generated by a heating element and ink is ejected from the bubbles is often used. There is.

FIG. 12 is a diagram showing a bubble jet recording head;
FIG. 12(A) is a sectional view of the main part of the recording head, FIG.
B) is an enlarged view of the heating element.

In the figure, a lower layer 2 is deposited on a substrate 1 made of an insulator, and a plurality of heating elements 3 and protection [4] separated from each other are formed thereon. Furthermore, a nozzle plate 6 provided with barriers 5 is installed on the protective film, and ink 7 is accommodated in the space surrounded by each barrier 5. 7a
is a steam bubble generated by the heat generated by the heating element 3. The nozzle plate 6 is formed by electroplating Ni on processed stainless steel and peeling it off to a thickness of about 70 to 80 μm. The hole diameter (nozzle diameter) of the nozzle 8 formed in the nozzle plate 6 is 20 to 30 μm, and the distance from the heating element to the nozzle 8 is 20 to 30 μm. In this case, the substrate l is made of glass. , the heating element 3 is Ta-
^l, the electrode 9 is ^l, the lower layer S between the substrate l and the heating element
10. The protective film 4 has a two-layer structure of 5isN4+ SiC. The pitch of the heating elements 3 is generally 80 to 150 μm (Ross R, AIIen et al.
: “Ther+sodynamics and Hyd
roddynamics of Thermal Ink
Jets” May 1985 pp21-27 (19
85)).

FIG. 13 is a diagram showing a second conventional recording head.

In the figure, 11 is a substrate made of silicon (Si) single crystal, and 12 is a heat storage layer of SiO□ which is coated on the substrate 11 and constitutes a thermal barrier. A heating element 13 made of Ta-Al is formed on the heat storage layer 12.

14 is an electrode made of AI, 15 is 5tjl14. stc
16 is a layer made of Ta. The protective film 15 and layer 16 cover the heating element 13 and the electrode 14 to protect them from chemical attack by ink.

Reference numeral 17 denotes an orifice plate in which ink nozzles 18 are formed, and an ink barrier 19 is formed to separate ink above the heating element 13.

Even in the recording head with the above configuration, its cross-sectional structure is complicated, and the work cost for forming the nozzles 18, ink barrier 19, etc. increases (Ronald A, A
skeland et ale”The 5econd
-Generation Thermal Ink
Jet 5structure'' Hewlett-P
ackard J.

Urnal August 1988 pp28-31
(198B)).

FIG. 14 is a diagram showing a third conventional recording head, FIG. 14(^) is a perspective view of the recording head, and FIG. 14(B) is a sectional view of the recording head.

In this case, a Si single crystal is processed by anisotropic etching. That is, both sides of the Si wafer 21 are oxidized to form Si.
After forming the NG films 22a and 22b, SiO is formed into a square shape with one side of a predetermined size using photolithography technology.
□Remove the film. Crystal planes (
By etching in the 100), (110), and (111) directions at a speed ratio of 50:30:3, an inverted pyramid-shaped nozzle 23 is finally formed. A head is formed by covering the nozzle row constituted by the nozzles 23 above the heating element row, but the manufacturing process is not necessarily easy (E, Ba5sous, H, etal"Ink
jet printing nozzle array
s etched in sit 0nApplied
Physics Letters, Vol. 31.
NO, 2+15-+ulyρp135-137 (19
77)).

In the bubble jet method using the recording heads shown in FIGS. 12 to 14, it is important to efficiently heat the ink in a short period of time and rapidly.

FIG. 15 is a diagram showing a fourth conventional recording head.

Model cavities 32 are formed at various locations on the heating element 31. When the upper surface of the heating element 31 having the above structure is filled with ink, bubbles 33 are first generated in the cavity 32 portion.

34 is an isolayer line formed in the ink above the heating element 31.

(Problems to be Solved by the Invention) However, in the conventional recording head described above, operations for forming nozzles, ink barriers, etc. are complicated, resulting in high manufacturing costs.

Furthermore, since the heating element is planar, it is not possible to heat the heating element efficiently.

The present invention solves the problems of the conventional recording head described above, and
It is an object of the present invention to provide a recording head that eliminates the need for an ink barrier to separate heating elements, reduces manufacturing costs, and improves heating efficiency.

(Means for Solving the Problems) For this purpose, in the recording head of the present invention, V-shaped, pyramid-shaped, etc. grooves are formed in the Si single crystal by anisotropic etching, and a plurality of inclined grooves forming the grooves are formed. A heat generating part is provided on the surface.

A plate is disposed opposite to the heat generating section, and the ink supplied into the groove is heated.

Nozzle holes for ejecting ink are formed in the plate.

(Function) According to the present invention, grooves in the shape of a 7-shape, a pyramid shape, etc. are formed in the Si single crystal by anisotropic etching as described above, and heat-generating portions are provided on the plurality of inclined surfaces forming the grooves. Therefore, the ink supplied into the groove is heated by the heat generating section.

A plate is disposed opposite the heat generating portion, and nozzle holes for ejecting ink are formed in the plate, so that the ink becomes bubbles and is ejected from the nozzle holes as an ink jet.

(Embodiments) Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

FIG. 1 is an assembled diagram of a recording head showing an embodiment of the present invention, FIG. 2 is a perspective view of a heating element portion of the recording head of the present invention, and FIG. 3 is a bottom view of the nozzle portion of the recording head of the present invention. be.

In FIG. 2, reference numeral 100 is a Si single crystal, which is processed into a ■-shaped structure with a flat surface at the top by anisotropic etching. Reference numeral 200 denotes a resistor layer serving as a heating element, and is formed by Si diffusion technology. Sheet resistance is 50Ω/mouth ~ 5
Typically, the sheet resistance is made by forming a P-type layer on an N-type single crystal using a diffusion technique.

101, 102.103. ... are slopes that generate Joule heat, P is the maximum width of the two slopes, h is the maximum depth of the two slopes, and W is the width of the flat part. The heating element pitch (P+11) is about 80 to 150 μ-.

It is sufficient for W to be 108 m, but it may be less than this.

301, 302. ...306 is an electrode formed on the flat surface. AI, NiCr-Au, Ti-Pt
- It is formed by vapor deposition using a material such as U to a thickness of about 1μ steel. The heating element section having this shape can be manufactured in large quantities at once from a Si single crystal wafer using so-called integrated circuit technology.

In addition, in FIG. 3, 400 is a plate with a thickness of about 20 to 80 μm, 311.312.313. ...316
are electrodes arranged at a pitch of (P+j1), 511.
512.513゜514, 515 are 20 to 30 μm in diameter
This is the nozzle hole. The plate 400 may be made of a polyimide film, glass resin, glass, or the like, as well as a material whose surface is made into an insulator by processing Si. Also, the nozzle holes 511, 512. ...The periphery of 515 is processed to make the thickness of that part 20 to 30 μ-.

As shown in FIG. 1, in addition to the head being formed by assembling the nozzle section shown in FIG. 3 to the heating element section shown in FIG.
02.603 is used. 601 is a plate having holes 604 for supplying ink to the head.

When the heating element part is set in the nozzle part, the electrode 311°3
12, 313. ... is the electrode 306.305.304.
... are electrically connected to each other. 602 is the wall, 6
A sealing material 03 is provided to prevent ink from flowing out and to firmly fix the plate 400, and is made of glass or other material. The electrical connection with the outside is easy, and the ink can be efficiently transferred to the nozzle hole 511°5.
12, . . . 515.

FIG. 4 is a perspective view of a heating element portion of a recording head showing a second embodiment of the invention, and FIG. 5 is an assembled view of the recording head showing a second embodiment of the invention.

In Fig. 4, 110 is a Si single crystal, 111.112
゜113, 114. ..., and 12L 122.12
3.124. ... are slopes obtained by etching the Si single crystal 110, and slopes 111.112.113.
114. ...A resistor layer is formed by diffusion. 311.312.313.314.315,...
・319 is an electrode for passing current through the resistor layer, -
It is connected to a driving circuit indicated by a dotted chain line Q.

321, 322, 323, and 324 are electrodes for connection with an external circuit.

As shown in FIG. 5, ink supply holes 521.522.degree. and electrodes 331.332.degree. ..., 334, etc. are formed. and the above electrodes 331.332. ..., 33
4 are electrodes 321, 322 . ..., electrically connected to 334 by pressure contact or brazing.

FIG. 6 is a perspective view of a heating element portion of a recording head showing a third embodiment of the present invention, FIG. 7 is a perspective view of a nozzle portion of a recording head showing a third embodiment of the present invention, and FIG. 8 FIG. 2 is an assembly diagram of a recording head showing a third embodiment of the present invention.

In FIG. 6, 120 is a Si single crystal, and discharge holes 531, 532, 533, 534 are formed by anisotropic etching.
535 is formed.

711, 712, 713, 714 are the discharge holes 531, ?
21.722723 and 724 are slopes made when forming the discharge hole 532. Below, 731. ...
, 754 are also similar.

Said slope 712. . . , 754 as well as the portions 761, 762 . . . indicated by broken lines. . . , 765 are resistance layers formed by diffusion technology and having a lower resistance than the base Si single junction 120.

350 is each resistance layer 761. ..., 765 common electrode 3
51.352°353, 354.355 are each resistance layer 76
11..., 765 are individual electrodes. Each of the above resistance layers 761. ..., Joule heat is generated in 765. .

Further, in FIG. 7, 612 is a plate having nozzle holes 641, 642, 643, 644, 645 for supplying ink. The plate is preferably formed of an insulator.

A recording head is formed by combining the heating element section and the nozzle section configured as described above. The joint portion is sealed from the outside with glass or the like.

FIG. 9 is a perspective view of a heating element portion of a recording head showing a fourth embodiment of the present invention.

In the figure, reference numeral 121 is a Si single crystal, on which an inverted pyramid nozzle is formed, and a heat generating resistor layer is formed on the slope of the nozzle.

800, 801.802. ... is a Si single crystal substrate 12
1, which supplies ink to each nozzle.

In this case, the portion indicated by the - dotted chain line Q is covered.

FIG. 10 is a perspective view of a heating element section of a recording head showing a fifth embodiment of the invention, and FIG. 11 is a perspective view of a nozzle section of a recording head showing a fifth embodiment of the invention.

In the figure, 122 is a Si single crystal, and the ■-shaped groove 7
00 is formed, and ink is supplied through the groove 700. Slopes on both sides of groove 700 701.702.703.70
4... A resistor layer for heat generation is formed. 300 is a common electrode of each heating element, 301.302. . . . is an individual electrode of each heating element.

Further, 900 is a plate that covers the heating element portion, and has nozzle holes 901, 902, . . . from which ink is ejected.

Note that the present invention is not limited to the above embodiments,
Various modifications are possible based on the spirit of the present invention, and these are not excluded from the scope of the present invention.

For example, in the above embodiment, the heating resistor layer is formed by diffusion, but it may also be formed by a P-N junction, or an insulating layer is formed on the surface after anisotropically etching a Si single crystal. It is also possible to form a heat storage layer by forming a resistor layer on the heat storage layer. Furthermore, the method of connecting the resistor layer and the electrode is not limited to the above method (effects of the invention) As explained in detail above, according to the present invention, a plurality of inclined planes are formed in the Si single crystal by anisotropic etching. Since the heating portion is provided on the inclined surface, it is possible to heat the ink from multiple directions simultaneously.

Therefore, bubbles can be generated efficiently.

Further, since the heat generating portion is formed on an inclined surface, the flow of ink is not affected by adjacent grooves, and stable operation can be obtained.

Moreover, since the inclined surface is formed by anisotropic etching, it is possible to form the ink barrier at the same time as the inclined surface, which simplifies the work.

[Brief explanation of the drawing]

FIG. 1 is an assembled diagram of a recording head showing an embodiment of the present invention, FIG. 2 is a perspective view of a heating element section of the recording head of the present invention, and FIG. 3 is a bottom view of the nozzle section of the recording head of the present invention. FIG. 4 is a perspective view of a heating element of a recording head showing a second embodiment of the invention, FIG. 5 is an assembled view of the recording head showing a second embodiment of the invention, and FIG. FIG. 7 is a perspective view of the nozzle section of the recording head showing the third embodiment of the present invention, and FIG. 8 is the third embodiment of the present invention. FIG. 9 is a perspective view of the heating element of the recording head showing a fourth embodiment of the present invention, and FIG. 10 is a recording head assembly diagram showing a fifth embodiment of the present invention. 11 is a perspective view of a nozzle portion of a recording head showing a fifth embodiment of the present invention; FIG. 12 is a diagram showing a bubble jet type recording head; FIG. A)
12(B) is an enlarged view of a heating element, FIG. 13 is a diagram showing a second conventional recording head, and FIG. 14 is a diagram showing a third conventional recording head. , Figure 14 (
A) is a perspective view of the recording head, FIG. 14(B) is a sectional view of the recording head, and FIG. 15 is a diagram showing a fourth conventional recording head. 100...Si single crystal, 101.102. ...Slope, 200...Resistance 3! Antibody layer, 311 312°...T4 pole, 400...Plate, 511°512,...Nozzle hole.

Claims (1)

[Claims] (a) A plurality of inclined surfaces formed in a silicon single crystal by anisotropic etching, (b) A heat generating portion formed on the inclined surfaces, (c) Opposing the heat generating portion. 1. A recording head comprising a plate provided with nozzle holes for ejecting ink.