Nozzle plate

A nozzle plate suited for a droplet generator is provided. The nozzle plate includes a nozzle layer and at least one filler. The nozzle layer has a nozzle and at least one trench. The nozzle passes through the nozzle layer. The trenches apart from the nozzle are formed on a surface of the nozzle layer around the nozzle. The filler is filled in the trench. The wetting angle of the surface of the filler is different from the wetting angle of the surface of the nozzle layer. The nozzle plate has higher surface wear resistance and lower probability of jamming at the nozzle.

CROSS-REFERENCE TO RELATED APPLICATION

This application claims the priority benefit of Taiwan application serial no. 94127837, filed on Aug. 16, 2005. All disclosure of the Taiwan application is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a nozzle plate. More particularly, the present invention relates to a nozzle plate with higher surface wear resistance and lower probability of jamming at the nozzle.

2. Description of Related Art

Digital jet-printing technology mainly relates to coat a carrier with tiny liquid drops according to a predetermined pattern. The ability of dwindling the liquid drops and control accuracy of a jet-printing position determine the level of printing resolution, and even the yield of a jet-printing element. Further, these qualities are closely related to the structure of the nozzle plate of the inkjet printhead. Therefore, the nozzle plate of a thermal bubble inkjet printhead or a piezoelectrical ink jet printhead has become a non-negligible key point of research and development.

U.S. Pat. No. 6,364,456 discloses a surface coating layer of a nozzle plate of an inkjet printhead, wherein the surface of the nozzle plate is fully coated with an anti-wetting material to form an anti-wetting layer. However, the inner edge of a nozzle near to the nozzle plate on the anti-wetting layer is easily wiped by a wiper used for cleaning and is thereby damaged, causing a deflection in direction of jetting the liquid drops.

U.S. Pat. No. 6,290,331 discloses a high efficiency nozzle plate and an inkjet printhead using the nozzle plate, wherein an anti-wetting material is formed at a recess of the nozzle of the nozzle plate to form an anti-wetting layer, such that the anti-wetting layer at the recess will not be wiped by the wiper used for cleaning. However, the residual solution at the recess of the nozzle cannot be wiped by the wiper, and jams the nozzle after drying.

U.S. Pat. No. 6,484,399 discloses an inkjet printhead and a fabricating method thereof, wherein after an anti-wetting layer is formed on a surface of the nozzle plate, a wettable layer is formed on the periphery of the nozzle of the nozzle plate surrounding the nozzle through a photolithography technique to separate currents of ink of different colors, thereby preventing inks of different colors from mixing with one another. However, the inner edge of the nozzle near to the nozzle plate on the anti-wetting layer is easily wiped by the wiper and gets damaged, causing a deflection in direction of jetting the liquid drops.

As current digital jet-printing technology is being continuously developed, industrial digital jet-printing technology has a development trend. Therefore, as for jet-printing requirements of industrial solution with multiple applications, the problems of how to enhance the surface wear resistance of the nozzle plate and overcome jamming at the nozzle of the nozzle plate have become increasingly important.

SUMMARY OF THE INVENTION

Accordingly, one object of the present invention is to provide a nozzle plate for a droplet generator to enhance the surface wear resistance thereof.

Another object of the present invention is to provide a nozzle plate to reduce the probability of jamming at a nozzle of the nozzle plate.

A further object of the present invention is to provide a nozzle plate to reduce the probability of ink mixture on a surface of an droplet generator.

In Accordance with the aforementioned and other objects of the present invention, a nozzle plate suitable for an droplet generator is provided. The nozzle plate comprises a nozzle layer and at least one filler. The nozzle layer comprises a nozzle and at least one trench, wherein the nozzle passes through the nozzle layer, and the trench formed apart from the nozzle is located on a surface of the nozzle layer around the nozzle. The filler is filled in the trench and a wetting angle of a surface of the filler is different from a wetting angle of the surface of the nozzle layer. Since the ink jet-printed by the nozzle plate includes solution containing a solvent base, a water base, and so on, a wetting angle of a surface of a local area on the periphery of the nozzle of the nozzle layer may be adjusted through the aforementioned filler in the present invention.

According to an embodiment of the present invention, the trench may comprise a ring shaped trench, a continuous trench, or a discontinuous trench.

According to an embodiment of the present invention, when the nozzle layer may have a plurality of ring shaped trenches, these trenches may concentrically encircle the nozzle.

According to an embodiment of the present invention, when the nozzle layer may have a plurality of trenches, these trenches may include at least one ring shaped trench and at least one radial trench, wherein the ring shaped trench and the radial trench are intercrossed with each other.

According to an embodiment of the present invention, the material of the nozzle layer may be a wettable material, and the material of the filler may be an anti-wetting material. In addition, the wettable material may include nickel, silicon, or a material containing soap bases. Furthermore, the anti-wetting material may include carbon tetrafluoride.

According to an embodiment of the invention, the material of the nozzle layer may be an anti-wetting material, and the material of the filler may be a wettable material. In addition, the anti-wetting material may include polyimide, and the wettable material may include nickel or a material containing soap bases.

Based on the above, in the present invention, the trench is formed in the periphery of the nozzle in the nozzle layer of the nozzle plate, and then a filler is filled into the trench. After a plurality of fillers are filled into the trenches respectively, an ink-concentrated area or a solution-concentrated area is formed on the surface of the periphery of the nozzle in the nozzle layer, so as to resist residual ink or solution from flowing to other areas of the surface of the nozzle layer.

In order to the make aforementioned and other objects, features and advantages of the present invention comprehensible, preferred embodiments accompanied with FIGs. are described in detail below.

DESCRIPTION OF EMBODIMENTS

FIG. 1Ais a top view of a nozzle plate according to a first embodiment of the present invention, andFIG. 1Bis a sectional view of Line I-I inFIG. 1A. Referring toFIGS. 1A and 1B, a nozzle plate100of the first embodiment is suitable for an droplet generator like an inkjet printhead or a nebulizer. The nozzle plate100comprises a nozzle layer110. The nozzle layer110has a nozzle112passing through the nozzle layer110, such that the droplet generator employing the nozzle plate100may jet ink drops or liquid drops via the nozzle112.

In order to prevent residual ink or solution on a surface110anear the nozzle112in the nozzle layer110from randomly flowing to other areas of the surface110aof the nozzle layer110, the nozzle layer110further comprises a trench114formed apart from the nozzle112, wherein the trench114is located on the surface110aof the nozzle layer110around the nozzle112. Additionally, the nozzle plate100further comprises a filler120which is filled in the trench114, wherein a wetting angle of a surface120aof the filler120is different from a wetting angle of the surface110aof the nozzle layer110.

In the first embodiment, when the material of the nozzle layer110is a wettable material, such as nickel, silicon, or a material containing soap bases, and the material of the filler120is an anti-wetting material, such as carbon tetrafluoride, the wetting angle of the surface120aof the filler120is larger than that of the surface110aof the nozzle layer110. On the contrary, when the material of the nozzle layer110is an anti-wetting material, such as polyimide, and the material of the filler120is a wettable material, such as nickel or a material containing soap bases, the wetting angle of the surface120aof the filler120is smaller than that of the surface110aof the nozzle layer110.

Regardless of material, the material may both form an ink-concentrated area or a solution-concentrated area on the surface110aaround the nozzle112in the nozzle layer110, such that the residual ink or solution on the surface110anear to the nozzle112in the nozzle layer110may not randomly flow to other areas of the surface110aof the nozzle layer110, thereby reducing the probability of ink mixture on the surface of the droplet generator.

Two methods of fabricating the nozzle plate according to the first embodiment will be illustrated accompanied with figures below, wherein the first method is to apply an additive process, while the second method is to apply a subtractive process.

FIGS. 2A-2Dshow the first method of fabricating the nozzle plate. Referring toFIG. 2A, a conductive carrier plate202is first provided and a first insulating pattern204and a second insulating pattern206are formed thereon, wherein the first insulating pattern204is disposed on the conductive carrier plate202, while the second insulating pattern206is disposed on the first insulating pattern204.

Referring toFIG. 2B, a nozzle layer208, comprised of, for example, nickel, is then formed on the conductive carrier plate202by means of electroforming, while a nozzle210and a trench212are formed on the nozzle layer208through the first insulating pattern204and the second insulating pattern206. Furthermore, the depth and profile of the trench212may be adjusted by changing thickness and profile of the second insulating pattern206.

Referring toFIG. 2C, after the nozzle layer208is formed, the conductive carrier plate202, the first insulating pattern204, and the second insulating pattern206are removed to expose the trench212of the nozzle layer208. It should be noted that the nozzle layer208may be formed using the electroforming process in order to facilitate the formation of the nozzle210directly in the nozzle layer208, so that after the first insulating pattern204is removed, a recess214covering the nozzle210and the trench212is formed on the nozzle layer208, wherein the trench212is located at the bottom of the recess214.

Referring toFIG. 2D, after the trench212is exposed, a filler216is filled in the trench212. Thus, the fabrication of the nozzle plate218is completed. First, a filling material is spin coated on the surface of the nozzle layer208such that the filling material fills into the trench212. Alternatively, the filling material may be coated using other known methods such as spraying, evaporation, dipping, and so on. Thereafter, portions of the filling material formed outside the trench212are removed by using of a plasma, and the filling material within the trench212serves as the filler216in the trench212. Furthermore, the filler216may also be formed within the trench212by using a called drop on demand.

FIGS. 3A-3Dshow the second method of fabricating the nozzle plate in the first embodiment. Referring toFIG. 3A, a nozzle layer302is provided, and two mask patterns304and306, partially exposing both sides of the nozzle layer302, are formed on both sides of the nozzle layer302, respectively, for example, by means of photolithography process. Referring toFIG. 3B, exposed portions of the nozzle layer302inFIG. 3Aare removed by means of etching to form a nozzle308and a trench310on the nozzle layer302. Furthermore, the profile and depth of the trench310is defined by the lower mask pattern306and controlling an etching rate. Referring toFIG. 3C, after the nozzle308and the trench310are formed on the nozzle layer302, the two mask patterns304and306are then removed. Referring toFIG. 3D, after the two mask patterns304and306are removed, a filler312is then filled in the trench310to complete the fabrication of the nozzle plate314. The method of filling the filler312in the trench310has been disclosed above, which is similar to that of filling the filler216in the trench212inFIG. 2D, and therefore it is described repeatedly.

It should be noted that in the first embodiment, only a single ring shaped continuous trench is formed on the nozzle layer of the nozzle plate, however trenches of different shapes and arrangements thereof, and number of trenches may also be used to achieve the purpose of the present invention, which is also construed to be within the scope of the present invention.

FIG. 4Ais a top view of a nozzle plate according to a second embodiment of the present invention, andFIG. 4Bis a sectional view of Line II-II shown inFIG. 4A. Referring toFIGS. 4A and 4B, the nozzle plate400according to the second embodiment has a nozzle layer410. The nozzle layer410has a nozzle412passing therethrough. Compared to the first embodiment described above which employs the single ring shaped continuous trench214of the nozzle layer210, two ring shaped continuous trenches414are formed on the nozzle layer410apart from the nozzle412, wherein the trenches414are formed on a surface410aof the nozzle layer410and concentrically encircle the nozzle412. In addition, in order to partially adjust wetness of the surface410aof the periphery of the nozzle412in the nozzle layer410, a plurality of fillers420are respectively filled in the trenches414, wherein a wetting angle of surfaces420aof these fillers420is different from a wetting angle of the surface410aof the nozzle layer410.

FIG. 5is a top view of a nozzle plate according to a third embodiment of the present invention. Referring toFIG. 5, the nozzle plate500of the third embodiment comprises a nozzle layer510. The nozzle layer510has a nozzle512passing therethrough. Compared to the second embodiment described with reference toFIG. 4A, three ring shaped discontinuous trenches514are formed on the nozzle layer510apart from the nozzle512, wherein the trenches514are located on a surface510aof the nozzle layer510and concentrically encircle the nozzle512. In addition, in order to partially adjust wetness of the surface510aof the periphery of the nozzle512of the nozzle layer510, a plurality of fillers520are respectively filled in these ring shaped discontinuous trenches514, wherein a wetting angle of surfaces520aof the fillers520is different from a wetting angle of the surface510aof the nozzle layer510.

FIG. 6is a top view of a nozzle plate of the fourth embodiment of the present invention. Referring toFIG. 6, the nozzle plate600in the fourth embodiment comprises a nozzle layer610. The nozzle layer610has a nozzle612passing therethrough. Compared to the second embodiment described with reference toFIG. 4A, a ring shaped continuous trench614aand a plurality of ring shaped discontinuous trenches614brespectively on the nozzle layer610apart from the nozzle612, wherein the trenches614aand614bare located on a surface610aof the nozzle layer610and concentrically encircle the nozzle612. The nozzle layer610further has a plurality of radial trenches614cformed apart from the nozzle612, wherein the trenches614care located on the surface610aof the nozzle layer610and intercrossed with these ring shaped discontinuous trenches614b. In addition, in order to partially adjust wetness of the surface610aof the periphery of the nozzle612in the nozzle layer610, a plurality of fillers620are respectively filled in these ring discontinuous trenches614, wherein a wetting angle of surfaces620aof these fillers620is different from a wetting angle of the surface610aof the nozzle layer610.

According to an aspect of the present invention, one or more trenches, including ring shaped continuous trenches, ring shaped discontinuous trenches or radial trenches may be formed on the nozzle layer to surround the nozzle in order to resist the residual ink or solution from flowing to other areas on the surface of the nozzle layer.

FIG. 7Ais a top view of a nozzle plate according to a fifth embodiment of the present invention, andFIG. 7Bis a sectional view of Line III-III inFIG. 7A. Referring toFIGS. 7A and 7B, the nozzle plate700according to the fifth embodiment has a nozzle layer710. The nozzle layer710has a nozzle712passing therethrough. Compared to the first embodiment described above which employs the filler120filled in the trench114in FIGS.1A and1B, the fifth embodiment omits the use of the filler120. Since a trench714, on a surface710aof the nozzle layer710and apart from the nozzle712, causes the discontinuity on the surface710a, and therefore effects the wettable property of the surface710a. Accordingly, the fifth embodiment omits the filler and consequently reduces the cost.

In view of the above, in the present invention, the trench is formed on the periphery of the nozzle in the nozzle layer of the nozzle plate with or without a filler filled therein to form an ink-concentrated area or a solution-concentrated area on the surface of the periphery of the nozzle in the nozzle layer to resist the residual ink or solution from flowing to other areas on the surface of the nozzle layer, thereby reducing the probability of mixing ink on the surface of the droplet generator, for example, reducing the probability of ink color mixing on the surface of a color droplet generator.

When the fillers are utilized, since side edges of the aforementioned fillers filled in the nozzle layer are not exposed, after the surface of the nozzle layer is wiped by the wiper used for cleaning, the fillers are not easily wiped by the wiper, thereby enhancing the surface wear resistance of the nozzle plate. In addition, since the inner wall of the nozzle of the nozzle layer has a specific property, for example, a wettable property or an anti-wetting property, the ink or solution passing through the nozzle is not easily retained or dried up in the nozzle. Thus, the probability of jamming at the nozzle may be substantially reduced.