KR101311281B1 - Inkjet nozzle assembly having moving roof structure and sealing bridge - Google Patents

Abstract

A nozzle assembly for an inkjet printhead is disclosed. The nozzle assembly includes a nozzle chamber having a ceiling with a nozzle opening formed therein. The ceiling includes a movable portion that is movable relative to the stop, whereby ink is ejected through the nozzle opening by the movement of the movable portion relative to the stop. The nozzle assembly also includes an actuator and a seal member for moving the moving part. The seal member is composed of bridge spanning between the moving part and the stop part.

Description

INKJET NOZZLE ASSEMBLY HAVING MOVING ROVING STRUCTURE AND SEALING BRIDGE}

TECHNICAL FIELD The present invention relates to the field of printers, and more particularly to inkjet printheads. The present invention was primarily developed to improve print quality and reliability in high resolution printheads.

Many different types of printing have been invented, many of which are currently in use. Known printing methods include various methods for printing a print medium with suitable marking media. Commonly used printing methods include offset printing, laser printing and laser copying devices, dot matrix impact printers, thermal paper printers, and film recorders. Thermal wax printers, dye sublimation printers, and inkjet printers provided in both drop on demand and continuous flow types. Each type of printer has its advantages and disadvantages, given the simplicity of price, speed, quality, reliability, structure and operation.

Recently, in the field of inkjet printing, a method of forming each individual pixel with ink ejected from one or more ink nozzles is becoming more and more popular due to its high quality and multipurpose feature.

Many different techniques for inkjet printing have been invented. J Moore writes in an overview of this area in his paper ("Non-Impact Printing: Introduction and Historical Perspective", Output Hard Copy Devices, Editors R Dubeck and S Sherr, pages 207-220 (1988)). Mentioned.

Inkjet printers come in many different types. The use of continuous streams of ink in inkjet printing is believed to be retroactive to at least 1929, of which Hansell US Patent No. 1,941,001 discloses a simple form of continuous stream electrostatic inkjet printing.

Sweet also discloses a continuous inkjet printing process in which US Pat. No. 3,596,275 includes a step in which the ink jet stream is deformed by a high frequency electro-static field to cause drop separation. Is disclosed. This technology is still used by several manufacturing companies, including Elmjet and Scitex (see US Patent No. 3,373,437 Suites et al.).

Piezoelectric inkjet printers are also one type of inkjet printing apparatus commonly used. Piezoelectric systems are disclosed in U.S. Patent No. 3,946,398 (1970) to Kyser et al. Using diaphragm mode of operation, and Zolton, who announced the squeeze mode of operation of a piezooelectric crystal. Zolten, U.S. Patent No. 3,683,212 (1970), Stemme's U.S. Patent No. 3,747,120 (1972), which announces the bend mode of piezoelectric driving, piezoelectric push mode of the inkjet stream US Pat. No. 4,459,601 to Howkins, which published the actuation of the ink jet stream, and US Pat. No. 4,584,590 to Fischbeck, which published the shear mode type of piezoelectric transducer element. It is disclosed in the call.

In recent years, thermal inkjet printing has become a very popular way of inkjet printing. This inkjet printing technique includes British Patent No. 2007162 (1979) published by Endo et al. And US Patent No. 4,490,728 published by Vaught et al. All of the above documents disclose an inkjet printing technique in which the action of an electrothermal actuator results in the creation of bubbles in a constricted space, such as a nozzle, by means of which the nozzle is connected from a hole connected to a confined space. Causes ejection of ink onto suitable print media. Printing devices using electrothermal actuators are made by manufacturers such as Canon and Hewlett-Packard.

As can be seen from the foregoing, several different types of printing techniques are available. In theory, the printing technique should have several desirable features. These features include high quality construction and operation for the price, high speed operation, safety and continuous long term operation. Each technology will have advantages and disadvantages in terms of price, speed, quality, reliability, power consumption, structure and operation simplicity, durability and consumption.

Applicants have described a number of inkjet printheads constructed using micro electro mechanical systems (MEMS). MEMS inkjet printheads are nozzle plates having moving portions, as described in the applicant's prior patent applications US 11 / 685,084, 11 / 763,443 and 11 / 763,440. It may include. Wherein the contents of the earlier applications are incorporated herein by reference. Typically, each moving part has a nozzle having an opening formed therein so as to drive the moving part when ejecting ink from the printhead.

The advantage of this type of printhead is that the energy required to eject droplets of ink is small compared to, for example, traditional thermal bubble-forming printheads. Applicant has previously described how a particular actuator design and complementary driving method provides high efficiency droplet ejection from such a printhead (e.g., U.S. Pat.Nos. 11 / 607,976 and 12 / 239,814. The contents of which are incorporated herein by reference).

However, a problem with 'movable nozzle' printheads is that they require a good fluid seal between the moving and stationary portions of the printhead. Ink should only be ejected through the nozzle opening and should not leak out of the seal. If the gap between the moving part and the stopping part is small, the surface tension may retain the ink inside the nozzle chambers. However, using ink surface tension as a fluid seal is problematic and usually cannot provide a reliable seal, especially if the ink inside the nozzle chambers is subjected to a pressure surge.

US Patent Applications Nos. 11 / 685,084, 11 / 763,443, and 11 / 763,440, both of which are the applicant's prior applications, describe a method of making a mechanical seal for a moving portion of a nozzle plate. Typically, a flexible layer of polydimethylsiloxane (PDMS) is applied on the nozzle plate, which acts as a sealing membrane between the moving and stopping portions of the printhead. The layer of PDMS also provides a hydrophobic ink jetting surface, which is also highly desired for printhead fluid and hence print quality.

It is desirable to provide improved mechanical seals for inkjet printheads with movable nozzles. In particular, it is desired to provide an effective mechanical seal with minimal impact on the overall efficiency of the printhead.

Summary of the Invention

In a first aspect, the present invention provides a nozzle assembly for an inkjet printhead,

A nozzle chamber having a nozzle opening formed therein, the nozzle chamber including a ceiling for allowing ink to be ejected through the nozzle opening by movement of the movement relative to the stop by including a moveable portion relative to the stop;

An actuator for moving the moving part relative to the stop part; And

A seal member configured as a bridge for bridging between the moving part and the stop part; It provides a nozzle assembly for an inkjet printhead comprising a.

Optionally, the member is made of a polymeric material.

Optionally, the polymeric material consists of polydimethylsiloxane (PDMS).

Optionally, the seal member has no space between the moving portion and the stop.

Optionally, the seal member has a non-planar profile configured to facilitate movement of the moving part.

Optionally, the seal member comprises at least one ridge and / or at least one furrow in the profile.

Optionally, said seal member comprises a crown portion, said crown portion standing up a first end of said seal member connected to said moving portion and a second end of said seal member connected to said stop.

Optionally, the seal member is corrugated.

Optionally, said nozzle opening is formed in said moving part.

Optionally, the nozzle opening is formed in the stop.

Optionally, the actuator comprises a first active element for connecting to a drive circuit; And

A thermal element, including a second passive element that mechanically cooperates with the first element, causing the first element to expand with respect to the second element when current passes through the first element, causing bending of the actuator It is a bend actuator (thermal bend actuator).

Optionally, the first and second elements are cantilever beams.

Optionally, the thermal bend actuator forms at least a portion of the moving part of the ceiling.

Optionally, the polymeric material is coated over a substantial part of the ceiling such that the ink ejection face of the printhead is hydrophobic.

Optionally, each ceiling forms at least a portion of the nozzle plate of the printhead, and each ceiling has a hydrophobic outer surface relative to the inner surface of each nozzle chamber by the polymer coating.

Optionally, the nozzle chamber includes sidewalls extending between the ceiling and the substrate such that the ceiling is spaced apart from the substrate.

Optionally, the moving portion is configured to move toward the substrate when the actuator is driven.

In yet another aspect, the invention provides an inkjet printhead comprising a plurality of nozzle assemblies, wherein each nozzle assembly comprises:

A nozzle chamber having a nozzle opening formed therein, the nozzle chamber including a ceiling for allowing ink to be ejected through the nozzle opening by movement of the moving portion relative to the stop by including a moving portion movable relative to the stop portion;

An actuator for moving the moving part relative to the stop part; And

A seal member interconnecting the moving part and the stop part; Including,

The seal member provides an inkjet printhead having a non-planar profile configured to facilitate movement of the moving part.

In a second aspect, the present invention,

Stop;

A plurality of moving parts for ink ejection; And

A plurality of seal members each connecting each moving part to the stop part; Including,

An inkjet printhead is provided, wherein each seal member is configured as a bridge that bridges between each moving portion and the stop.

Optionally, said nozzle plate comprises a plurality of moving parts and stops.

Optionally, said nozzle plate comprises a flexible polymer coating, said coating comprising said seal members.

Optionally, the polymer coating is hydrophobic.

Optionally, the polymer coating consists of polydimethylsiloxane (PDMS).

Optionally, the seal member has no space between the moving portion and the stop.

Optionally, the seal member has a non-planar profile configured to facilitate movement of the moving part.

Optionally, the seal member comprises at least one ridge and / or at least one groove in the profile.

Optionally, each seal member includes a crown portion, the crown portion standing up a first end of the seal member connected to the moving part and a second end of the seal member connected to the stop.

Optionally, the seal member is corrugated.

In still another aspect, the invention provides a printhead comprising a plurality of nozzle assemblies, wherein each nozzle assembly comprises:

A nozzle chamber having a nozzle opening formed therein, the nozzle chamber including a ceiling for allowing ink to be ejected through the nozzle opening by movement of the moving portion relative to the stop by including a moving portion movable relative to the stop portion;

An actuator for moving the moving part relative to the stop part; And

One of the seal members for crosslinking between the moving part and the stop part; It provides a printhead comprising a.

Optionally, said nozzle opening is formed in said moving part.

Optionally, the nozzle opening is formed in the stop.

Optionally, the actuator comprises: a first active element for connecting to a drive circuit; And

A thermal bend actuator, including a second passive element that mechanically cooperates with the first element, causes the first element to expand with respect to the second element when current passes through the first element, causing bending of the actuator.

Optionally, the first and second elements are cantilevered.

Optionally, the thermal bend actuator forms at least a portion of the moving part of the ceiling.

Optionally, the nozzle chamber includes sidewalls extending between the ceiling and the substrate such that the ceiling is spaced apart from the substrate.

Optionally, the moving portion is configured to move toward the substrate when the actuator is driven.

Optionally, the ceiling and the sidewalls are made of a ceramic material that can be deposited by CVD, the ceramic material being selected from the group comprising silicon nitride, silicon oxide and silicon oxynitride.

In still another aspect, the present invention provides an inkjet printhead comprising the printhead according to claim 1.

In a third aspect, the present invention provides a method of manufacturing an inkjet nozzle assembly having a seal member that crosslinks between a moving portion and a stop portion.

(a) providing a partially manufactured printhead comprising a ceiling sealed nozzle chamber;

(b) forming the moving part on the first side of the via by etching the via through the ceiling and forming the stop on the second side of the via;

(c) plugging the via with a plug of sacrificial material;

(d) depositing a layer of flexible material over at least the plug;

(e) providing the inkjet nozzle assembly having the seal member that bridges between the moving portion and the stop by removing the plug; It provides a method of manufacturing an inkjet nozzle assembly comprising a.

Optionally, the flexible material is a polymeric material.

Optionally, the flexible material consists of polydimethylsiloxane (PDMS).

Optionally, the plug fills the via so that the seal member is free of the via.

Optionally, the plug has a head extending from the via, the head having a scaffold surface for the deposition of the flexible material.

Optionally, the seal member has a non-planar profile configured to facilitate movement of the moving part.

Optionally, the seal member comprises at least one ridge and / or at least one groove in the profile.

Optionally, the seal member comprises a crown portion, the crown portion standing up a first end of the seal member connected to the moving part and a second end of the seal member connected to the stop.

Optionally, the seal member is corrugated.

In yet another aspect, the invention provides a method further comprising etching the nozzle opening through the ceiling prior to removing the sacrificial material.

Optionally, the nozzle opening is etched through the moving part.

Optionally, said moving part comprises a thermal bend actuator.

Optionally, the thermal bend actuator comprises: a first active element for connecting to a drive circuit; And

A second passive element, which mechanically cooperates with the first element, causes the first element to expand relative to the second element as the current passes through the first element, causing bending of the actuator.

Optionally, the flexible material is a hydrophobic material, and the flexible material is deposited over a substantial portion of the ceiling such that the ceiling is relatively hydrophobic.

Optionally, the moving part is configured to move toward the substrate when the actuator is driven.

Optionally, the sacrificial protective metal layer is removed after removing the plug.

Optionally, the plug is removed by exposing the nozzle assembly to oxidizing plasma.

In still another aspect, the present invention provides an inkjet nozzle assembly having a seal member that bridges between a moving portion and a stop, wherein the seal member is made of a flexible material deposited on a ceiling of the nozzle assembly. .

1 is a cross-sectional side view of a partially manufactured inkjet nozzle assembly after the sequence of first steps of forming nozzle chamber sidewalls;
FIG. 2 is a perspective view of the partially manufactured inkjet nozzle assembly shown in FIG. 4. FIG.
Figure 3 is a side cross-sectional view of a partially manufactured inkjet nozzle assembly after the sequence of the second step of filling the nozzle chamber with polyimide.
4 is a perspective view of the partially manufactured inkjet nozzle assembly shown in FIG.
5 is a side cross-sectional view of a partially manufactured inkjet nozzle assembly after the third step sequence of forming connector posts to the chamber ceiling;
FIG. 6 is a perspective view of the partially manufactured inkjet nozzle assembly shown in FIG. 5. FIG.
FIG. 7 is a side cross-sectional view of a partially manufactured inkjet nozzle assembly after the fourth step sequence of forming a conductive metal plate. FIG.
FIG. 8 is a perspective view of the partially manufactured inkjet nozzle assembly shown in FIG. 7. FIG.
9 is a side cross-sectional view of a partially manufactured inkjet nozzle assembly after the sequence of the fifth step of forming the active beam member of the thermal bend actuator.
FIG. 10 is a perspective view of the partially manufactured inkjet nozzle assembly shown in FIG. 9. FIG.
11 is a side cross-sectional view of a partially manufactured inkjet nozzle assembly after the sixth step sequence of forming a moving ceiling comprising a thermal bend actuator;
12 is a perspective view of the partially manufactured inkjet nozzle assembly shown in FIG.
FIG. 13 is a side cross-sectional view of a partially manufactured inkjet nozzle assembly after the seventh step sequence of depositing and photopatterning the hydrophobic polymer layer. FIG.
FIG. 14 is a perspective view of the partially manufactured inkjet nozzle assembly shown in FIG. 23. FIG.
Figure 15 is a side cross-sectional view of a fully formed inkjet nozzle assembly.
FIG. 16 is a cutaway perspective view of the inkjet nozzle assembly shown in FIG. 15. FIG.
FIG. 17 is a schematic side cross-sectional view of the partially manufactured inkjet nozzle assembly shown in FIGS. 9 and 10.
FIG. 18 is a schematic side cross-sectional view of the partially manufactured inkjet nozzle shown in FIG. 17 after etching the via to form a moving portion and a stop of the chamber ceiling; FIG.
FIG. 19 is a schematic side cross-sectional view of the partially manufactured inkjet nozzle shown in FIG. 18 after filling the via with a plug of photoresist. FIG.
FIG. 20 is a schematic side cross-sectional view of the partially manufactured inkjet nozzle shown in FIG. 19 after depositing a polymer layer and a protective metal layer. FIG.
FIG. 21 is a schematic side cross-sectional view of the partially manufactured inkjet nozzle shown in FIG. 20 after etching the nozzle opening. FIG.
Figure 22 is a schematic side cross-sectional view of an inkjet nozzle assembly in accordance with the present invention.
23 is a schematic side cross-sectional view of another seal member.

Detailed Description of the Specific Embodiment

1 and 16 illustrate the MEMS manufacturing steps of the inkjet nozzle assembly 100 described in Applicant's prior application US patent application Ser. No. 11 / 763,4406, the contents of which are incorporated herein by reference. The completed inkjet nozzle assembly 100 shown in FIGS. 15 and 16 utilizes thermal bend actuation, whereby the moving portion of the ceiling is bent toward the substrate to cause ink jetting.

The starting point for MEMS fabrication is a standard CMOS wafer with a CMOS drive circuit formed on top of a silicon wafer. At the end of the MEMS fabrication process, the wafer is diced into individual printhead integrated circuits (ICs), each IC comprising a drive circuit and a plurality of nozzle assemblies.

As shown in Figs. 1 and 2, the substrate 1 has an electrode 2 formed at its upper portion. The electrode 2 is one of a pair of adjacent electrodes (positive and earth) for powering the actuator of the inkjet nozzle 100. These electrodes are powered from a CMOS drive circuit (not shown) of the upper layers of the substrate 1.

The other electrode 3 shown in Figs. 1 and 2 is for supplying power to an adjacent inkjet nozzle. In general, these figures show the MEMS manufacturing steps for a nozzle assembly that is one of an array of nozzle assemblies. The following description focuses on the manufacturing steps for one of these nozzle assemblies. However, it will of course be appreciated that the corresponding steps are executed simultaneously for all the nozzle assemblies formed on the wafer. Although adjacent nozzle assemblies are partially shown in the figures, this may be ignored for this purpose. Therefore, hereinafter, all the features of the adjacent nozzle assembly and the electrode 3 will not be described in detail. Indeed, for clarity, several MEMS manufacturing steps will not be shown for adjacent nozzle assemblies.

In the step sequence shown in Figs. 1 and 2, an 8 micron silicon dioxide layer is first deposited on the substrate 1. The depth of the silicon dioxide defines the depth of the nozzle chamber 5 for the ink jet nozzle. After deposition of the SiO ₂ layer, the layer is etched to form walls 4, which become the side walls of the nozzle chamber 5, as most clearly shown in FIG. 2.

As shown in FIGS. 3 and 4, the nozzle chamber 5 is then filled with a photoresist or polyimide 6 which acts as a sacrificial scaffold for subsequent deposition steps. The polyimide 6 is spun onto a wafer using standard techniques, UV cured and / or hardbaked, followed by a chemical mechanical polishing (CMP) treatment that stops at the top side of the SiO ₂ wall 4. Will receive.

5 and 6, highly conductive connector posts 8 are formed which extend down to the electrode 2 as well as the ceiling 7 of the nozzle chamber 5. First, a 1.7 micron SiO ₂ layer is deposited on the polyimide 6 and on the wall 4. This SiO ₂ layer forms the ceiling 7 of the nozzle chamber 5. Next, a pair of vias are formed in the wall 4 down to the electrodes 2 using standard anisotropic DRIE. This etching exposes the pair of electrodes 2 through each via. Next, vias are filled with a highly conductive metal such as copper using electroless pating. The deposited copper posts 8 are CMP treated to stop at the SiO ₂ ceiling 7 to provide a planar structure. It can be seen that the copper connector posts 8 formed during the electroless copper plating encounter each electrode 2 to provide a linear conductive path up to the ceiling 7.

In FIGS. 7 and 8, metal pads 9 are formed by first depositing a 0.3 micron layer of aluminum over the ceiling 7 and the connector posts 8. Highly conductive metals (eg, aluminum, titanium, etc.) should be deposited to a thickness of about 0.5 microns or less in order to use any and to not have too much influence on the overall planarity of the nozzle assembly. Metal pads 9 are formed in the ceiling 7 and the connector posts 8 in predetermined 'bend regions' of the thermoelastic active beam member.

9 and 10, a thermoelastic active beam member 10 is formed on the SiO ₂ ceiling 7. By being fused to the active beam member 10, a portion of the SiO ₂ ceiling 7 is formed by the lower passive beam member 16 of the mechanical thermal bend actuator formed by the active beam 10 and the passive beam 16. Act as. The thermoelastic active beam member 10 may be made of any suitable thermoelastic material such as titanium nitride, titanium aluminum nitride and aluminum alloy. A vanadium-aluminum alloy is the preferred material, as described in US Patent Application No. 11 / 607,976, filed December 4, 2002, the applicant's prior application. This is because the alloy combines advantageous properties such as high thermal expansion, low density and high Young's module.

To form the active beam member 10, a layer of 1.5 micron active beam material is first deposited by standard PECVD. Next, the beam material is etched using standard metal etching to form the active beam member 10. After completion of the metal etching, as shown in FIGS. 9 and 10, the active beam member 10 includes a partial nozzle opening 11 and a beam element 12, each of which has an angle thereof. At the end it is electrically connected to the positive and ground electrodes 2 via connector posts 8. The planar beam element 12 is bent about 180 degrees extending from the top of the first (positive) connector post and back to the top of the second (ground) connector post.

9 and 10, the metal pads 9 are positioned to facilitate current flow in the region of potentially high resistance. One metal pad 9 is located in the bending area of the beam element 12 and is interposed between the active beam member 10 and the passive beam member 16. The other metal pad 9 is located between the top of the connector posts 8 and the end of the beam element 12.

11 and 12, the SiO ₂ ceiling 7 is etched to completely form the nozzle opening 13 and the moving portion 14 of the ceiling. The moving part 14 includes a thermal bend actuator 15, which itself is composed of an active beam member 10 and a lower active beam member 16. The nozzle opening 13 is formed in the moving part 14 so as to move according to the actuator during driving. A configuration in which the nozzle opening 13 is fixed relative to the moving part 14 is also possible as described in US Patent Application No. 11 / 607,976, which is incorporated herein by reference.

A perimeter gap 17 around the moving part 14 of the ceiling separates the moving part from the stop 18 of the ceiling. This gap 17 causes the moving part 14 to be bent toward the nozzle chamber 5 and towards the substrate 1 when the actuator 15 is driven.

With reference to FIGS. 13 and 14, a photopatternable hydrophobic polymer layer 19 is deposited over the entire nozzle assembly, photopatterned, and then the nozzle opening 13 is formed again.

The use of photopatternable polymers to coat arrays of nozzle assemblies is described in US Patent Application No. 11 / 685,084 filed March 12, 2007 and US Patent Application No. 11 / April 27, 2007 740,925, the disclosure of which is incorporated herein by reference in its entirety. Typically, the hydrophobic polymer is polydimethylsiloxane (PDMS) or perfluorinated polyethylene (PFPE). Such polymers are particularly advantageous because they are photopatternable and have high hydrophobicity and low Young modules.

As described in the above-mentioned US patent applications, the exact sequence of MEMS manufacturing steps is relatively flexible by incorporating hydrophobic polymers. For example, it is completely possible to etch the nozzle opening 13 after deposition of the hydrophobic polymer 19 and to use such a polymer as a mask for nozzle etching. It will be appreciated that changes in the exact order of MEMS manufacturing steps are within the scope of the skilled person and are also within the scope of the present invention.

The hydrophobic polymer layer 19 performs several actions. Firstly, the gap 17 is filled to provide a mechanical seal between the moving portion 14 and the stop 18 of the ceiling 7. If the polymer has a low Young's module, the actuator can still be bent towards the substrate 1, but can prevent ink from escaping through the gap 17 during driving. Secondly, the polymer has a high hydrophobicity which minimizes the tendency of ink to leak into the inkjet surface 21 of the printhead and the relatively hydrophilic nozzle chamber. Third, the polymer acts as a protective layer to facilitate printhead maintenance.

Finally, as shown in FIGS. 15 and 16, the ink supply channel 20 is etched from the back surface of the substrate 1 to the nozzle chamber 51. Although the ink supply channel 20 is shown aligned with the nozzle opening 13 in FIGS. 15 and 16, it can of course be located away from the nozzle opening.

Following etching of the ink supply channel, the nozzle assembly 5 is removed by ashing (either front ashing or back ashing), for example, by using an O ₂ plasma. Form 100.

Although not described above, the polymer may be subjected to the final stage of MEMS processing, as described in the Applicants' prior patent applications US 11 / 740,925 and 11 / 946,840, the contents of which are incorporated herein by reference. In order to protect the layer 19, a metal film (for example, titanium or aluminum) may be used. Typically, a protective metal film is deposited over the polymer layer 19 before etching the nozzle opening 13. After completion of all etching and oxidative photoresist removal steps (“ashing steps”), the protective metal film may be removed using a simple HF or H ₂ O ₂ rinse.

With moving parts Stop  Space between Crosslinked The polymer  Having nozzle assembly

In the nozzle assembly 100 described above, the polymer layer 19 fills the gap between the moving portion 14 and the stop 18 of the ceiling 7. Although this provides a good mechanical seal and can be manufactured immediately, the configuration of the seal inevitably affects the overall performance and efficiency of the nozzle assembly.

Returning to FIGS. 17-22, an alternative sequence of manufacturing steps is schematically illustrated, which improves the sealing member that bridges between the moving portion 14 and the stop 18. For simplicity, the detailed structure of the actuator is not shown in the schematic illustration of FIGS. 17 to 22. However, it will be appreciated that FIG. 17, a starting point for this sequence of alternative manufacturing steps, schematically illustrates the partially formed nozzle assembly shown in FIGS. 9 and 10. For clarity, the same reference numerals will be used to indicate the corresponding structures in the nozzle assembly.

Next, referring to FIG. 17, a partially formed nozzle assembly is shown in which the nozzle chamber 5 is filled with polyimide 6. The ceiling 7 including the thermal bend actuator forms a cover over the nozzle chamber 5.

In FIG. 18, the via is etched into the ceiling 7. The via forms a gap 17 between the moving part 14 and the stop 18 of the ceiling 17.

Next, referring to FIG. 19, the gap 17 is filled with a plug 30 of a sacrificial material such as a photoresist. The plug 30 serves as a sacrificial scaffold for the deposition of the polymer seal member in a subsequent step. Specifically, the upper surface of the plug 30 forms a profile of the seal member. The shape of the plug 30 and the profile of its upper surface may be adjusted by conventional photolithographic techniques. For example, the oblique sidewalls of the plug 30 may be formed by adjusting the focusing parameters during exposure of the photoresist.

Following formation of the plug 30, the partially formed nozzle assembly is applied with a layer of flexible polymer material 19. Typically, the polymeric material is polydimethylsiloxane (PDMS). As shown in FIG. 20, the PDMS layer 19 is matched to the profile of the top surface of the nozzle assembly.

A protective aluminum film 31 is then deposited over the PDMS layer 19. The aluminum film 31 protects the PDMS layer 19 from the oxide plasma to remove the polyimide 6 (Fig. 22).

Referring now to FIG. 21, nozzle openings 13 are formed by etching through aluminum film 31, PDMS layer 19, and ceiling 17. This etching requires different etch chemistry at different stages in order to etch all three layers.

Finally, referring to FIG. 22, the nozzle assembly is subjected to an oxidizing plasma (eg, O ₂ plasma) to remove the polyimide 6 and the photoresist plug 30. Following oxidation removal of the polyamide 6 and plug 30, the protective aluminum layer 31 is removed by washing with HF or H ₂ O ₂ .

The completed nozzle assembly 200 shown in FIG. 22 has a seal member 32 that bridges through a gap 17 between the moving portion 14 and the stop 18 of the ceiling 17. Remarkably, the seal member 32 does not fill the gap 17 and in fact there is no space between the moving portion 14 and the stop 18.

The seal member 32 has a profile of a bridge, one end of which is connected to the moving part 14 and the other end of which is connected to the stop 18. The bridge also substantially takes the form of a single arch bridge with ridges or crowns 33 standing each end of the bridge. Of course, the seal member may alternatively take the form of a simple beam bridge which bridges between the moving part 14 and the stop 18, depending on the profile of the upper surface of the plug 30. have.

The seal member 32 has many advantages over the embodiment shown in FIGS. 15 and 16, where the gap 17 is completely filled with polymeric material 19. First, by reducing the total volume of polymer between the mover 14 and the stop 18, the impedance for the downward motion of the mover 14 towards the substrate 1 becomes much smaller. In addition, the profile of the seal member is specifically configured to facilitate the downward movement of the moving part 14. Since the seal member 32 is in the form of a flexible bridge, if the seal member 32 has a length longer than the distance between the movable portion 14 and the stop 18, any downward motion of the movable portion 14 during driving may cause It can be achieved directly by the bridge structure with minimum flexing and extension. Therefore, the seal member 32 provides the minimum impedance for the movement of the moving part 14, but still provides excellent sealing. By minimizing the impedance to the movement of the moving part 14, the overall efficiency of the nozzle assembly 200 and the printhead containing such nozzle assembly are improved.

Of course, other configurations of the seal member 32 are included within the scope of the present invention. For example, as shown in FIG. 23, the seal member 32 may be a corrugated structure 40 having a plurality of raised portions 41 and grooves 42. It will be appreciated that the corrugated structure 40 can immediately achieve the movement of the moving part 14.

It will be apparent to those skilled in the art that many changes and modifications can be made to the present invention as set forth in the specific embodiments without departing from the spirit or scope of the broadly described invention. Accordingly, the present invention is to be considered in all respects as illustrative and not restrictive.

Claims (20)

A nozzle assembly for an inkjet printhead,
A nozzle chamber having a nozzle opening formed therein, the nozzle chamber including a ceiling for allowing ink to be ejected through the nozzle opening by movement of the movement relative to the stop by including a moveable portion relative to the stop;
An actuator for moving the moving part relative to the stop part; And
A seal member configured as a bridge that bridges between the moving portion and the stop portion; Nozzle assembly for an inkjet printhead comprising a. The method of claim 1,
And the seal member is made of a polymer material. The method of claim 2,
And said polymeric material is comprised of polydimethylsiloxane (PDMS). The method of claim 1,
And the seal member has no space between the moving part and the stop part. The method of claim 1,
And the seal member has a non-planar profile configured to facilitate movement of the moving part. The method of claim 1,
And the seal member comprises at least one ridge, at least one furrow, or at least one ridge and at least one groove in the profile. 5. The method of claim 4,
The seal member includes a crown portion, wherein the crown portion stands for a first end of the seal member connected to the moving part and a second end of the seal member connected to the stop part. Assembly. The method of claim 1,
And the seal member is corrugated. The method of claim 1,
And the nozzle opening is formed in the moving part. The method of claim 1,
And the nozzle opening is formed in the stop. The method of claim 1,
The actuator includes a first active element for connecting to a drive circuit; And
A thermal element, including a second passive element that mechanically cooperates with the first element, causing the first element to expand with respect to the second element when current passes through the first element, causing bending of the actuator Nozzle assembly for inkjet printheads, which is a thermal bend actuator. delete delete delete delete delete delete delete delete delete

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