KR20030024671A - Ink Jet Printhead Nozzle Array - Google Patents

Abstract

The inkjet printhead nozzle array 14 includes a plurality of nozzle assemblies 10. Each nozzle assembly 100 includes an ink jet nozzle 22, an actuator 28 and a connecting member 26 interconnecting the actuator 28 and the nozzle 22. The nozzle assembly 10 is heated 72, 74. The nozzles 22 of the assembly 10 in one row 72 are located between the connecting members 26 of adjacent nozzle assemblies 10 in the other row 74. Two The actuators 28 of the assembly 10 in rows 72, 74 are arranged on the same side of rows 72, 74.

Description

Ink Jet Printhead Nozzle Array

In inkjet printheads, the denser the array of nozzles, the better the print quality.

Also, when the nozzle is stationary and the actuator is used to eject ink from the nozzle, such ink is ejected almost perpendicularly to the object. However, when the nozzle is displaceable, the ink is ejected from the nozzle at a slight angle. If the nozzles arranged are arranged in opposite directions, such as, for example, mirror images of one another, the ink droplets ejected from such nozzles are considerably deviated from the vertical. This can lead to deterioration of print quality.

The present invention relates to an inkjet printhead. More particularly, the present invention relates to an inkjet printhead nozzle array.

(Applications pending together)

Various methods, systems and apparatuses associated with the present invention are disclosed in the following application filed concurrently with this application by the applicant or successor.

PCT / AU00 / 00518, PCT / AU00 / 00519, PCT / AU00 / 00520, PCT / AU00 / 00521, PCT / AU00 / 00522, PCT / AU00 / 00523, PCT / AU00 / 00524, PCT / AU00 / 00525, PCT / AU00 / 00526, PCT / AU00 / 00527, PCT / AU00 / 00528, PCT / AU00 / 00529, PCT / AU00 / 00530, PCT / AU00 / 00531, PCT / AU00 / 00532, PCT / AU00 / 00533, PCT / AU00 / 00534, PCT / AU00 / 00535, PCT / AU00 / 00536, PCT / AU00 / 00537, PCT / AU00 / 00538, PCT / AU00 / 00539, PCT / AU00 / 00540, PCT / AU00 / 00541, PCT / AU00 / 00542, PCT / AU00 / 00543, PCT / AU00 / 00544, PCT / AU00 / 00545, PCT / AU00 / 00547, PCT / AU00 / 00546, PCT / AU00 / 00554, PCT / AU00 / 00556, PCT / AU00 / 00557, PCT / AU00 / 00558, PCT / AU00 / 00559, PCT / AU00 / 00560: PCT / AU00 / 00561, PCT / AU00 / 00562, PCT / AU00 / 00563, PCT / AU00 / 00564, PCT / AU00 / 00565, PCT / AU00 / 00566, PCT / AU00 / 00567, PCT / AU00 / 00568, PCT / AU00 / 00569, PCT / AU00 / 00570, PCT / AU00 / 00571, PCT / AU00 / 00572, PCT / AU00 / 00573, PCT / AU00 / 00574, PCT / AU00 / 00575, PCT / AU00 / 00576, PCT / AU00 / 00577, PCT / AU00 / 00578, PCT / AU00 / 00579, PCT / AU00 / 00581, PCT / AU00 / 00580, PCT / AU00 / 00582, PCT / AU00 / 00587, PCT / AU00 / 00588, PCT / AU00 / 00589, PCT / AU00 / 00583, PCT / AU00 / 00593, PCT / AU00 / 00590, PCT / AU00 / 00591, PCT / AU00 / 00592, PCT / AU00 / 00584, PCT / AU00 / 00585, PCT / AU00 / 00586, PCT / AU00 / 00594, PCT / AU00 / 00595, PCT / AU00 / 00596, PCT / AU00 / 00597, PCT / AU00 / 00598, PCT / AU00 / 00516, PCT / AU00 / 00517, PCT / AU00 / 00511, PCT / AU00 / 00501, PCT / AU00 / 00502, PCT / AU00 / 00503, PCT / AU00 / 00504, PCT / AU00 / 00505, PCT / AU00 / 00506, PCT / AU00 / 00507, PCT / AU00 / 00508, PCT / AU00 / 00509, PCT / AU00 / 00510, PCT / AU00 / 00512, PCT / AU00 / 00513, PCT / AU00 / 00514, PCT / AU00 / 00515

The contents disclosed in the above-listed applications are hereby incorporated by reference.

With reference to the accompanying drawings, the present invention will be described by way of example.

1 is a three-dimensional, schematic view of a nozzle assembly for an inkjet printhead.

2 to 4 are three-dimensional, schematic views for explaining the operation of the nozzle assembly of FIG.

5 is a three-dimensional view of the nozzle array according to the present invention constituting the inkjet printhead.

6 is an enlarged view of a portion of the array of FIG. 5.

7 is a three-dimensional view of an inkjet printhead including nozzle protection means.

8A-8R show three-dimensionally the manufacturing steps of the nozzle assembly of the inkjet printhead.

9A to 9R are side cross-sectional views of the manufacturing step.

10A to 10K show the layout of a mask used in various stages of the manufacturing process.

11A-11C are three-dimensional views of the operation of a nozzle assembly made according to the method of FIGS. 8 and 9.

12A-12C are side cross-sectional views illustrating the operation of the nozzle assembly manufactured according to the method of FIGS. 8 and 9.

According to the present invention, there is provided an inkjet printhead nozzle comprising a plurality of nozzle assemblies, each nozzle assembly comprising an ink jet nozzle and an actuator, and a connecting member interconnecting the nozzle and the actuator, the nozzle assembly Are arranged in rows with the nozzles of one row of assemblies, the rows of connecting members of adjacent nozzle assemblies of the other rows, and the two rows of assemblies arranged on the same side of the rows. Located between actuators.

In the present specification, the term "nozzle" is to be understood as the component forming the opening, not the opening itself.

The nozzles in each assembly are movable and displaceable by connected actuators to effect ink jet ejection.

The actuator of each assembly is a thermal bend actuator and the connecting member is in the form of an arm, the arm having one end connected to it extending from the actuator and fixed to the opposite end of the movable part. It is equipped with a nozzle.

The other row of actuators is received between the row of connecting members.

The nozzle of the assembly is formed to facilitate close packing of the nozzle. Preferably, the nozzle is almost hexagonal in shape.

The printhead may be a multicolor printhead, each color having two rows of nozzle assemblies associated with each color, with the actuators in all rows extending in the same direction.

First, referring to FIG. 1, a nozzle assembly according to the present invention is generally indicated with reference 10. The inkjet printhead has a plurality of nozzle assemblies 10 arranged in an ink array 14 (FIGS. 5 and 6) on a silicon substrate 16. The array 14 will be described in detail below.

The assembly 10 includes a silicon substrate or wafer 16 on which a dielectric layer 18 is deposited.

Each nozzle assembly 12 includes a nozzle 22 forming a nozzle opening 24, a connecting member in the form of a lever arm 26, and an actuator 28. The lever arm 26 connects the actuator 28 to the nozzle 22.

As shown in more detail in FIGS. 2 to 4, the nozzle 22 includes a crown portion 30 having a skirt portion 32, wherein the skirt portion 32 is the crown portion. It hangs from the (crown portion) 30. The skirt portion 32 forms part of the circumferential wall of the nozzle chamber 34 (FIGS. 2-4). The nozzle opening 24 is connected to the nozzle chamber 34 so that the fluid flows. The nozzle opening 24 is formed by a raised rim 36 that “constrains” the meniscus 38 (FIG. 2) of the ink mass 40 in the nozzle chamber 34. Note that it is surrounded.

An ink inlet hole 42 (shown most clearly in FIG. 6) is formed in the bottom 46 of the nozzle chamber 34. The hole 42 is connected to the fluid and the ink inlet channel 48 formed through the substrate 16.

The wall portion 50 delimits the hole 42 and extends upwardly from the bottom 46. As indicated above, the skirt portion 32 of the nozzle 22 forms the first part of the circumferential wall of the nozzle chamber 34, and the wall portion 50 is the circumferential wall of the nozzle chamber 34. To form the second part.

The wall 50 has a lip 52 facing inward at its free end, which, when the nozzle 22 is disposed, prevents leakage of ink. Acts as a fluid seal to prevent and will be described in more detail below. Due to the viscosity of the ink 40 and the narrow space between the lip 52 and the skirt portion 32, the lip 52 and the surface tension facing inwardly may cause the ink from the nozzle chamber 34 to be absorbed. It will be appreciated that it acts as an effective seal to prevent leakage.

The actuator 28 is a thermal bend actuator and is connected to an anchor 54 extending upward from the substrate 16 or, in particular, the CMOS passivation layer 20. . The anchor 54 is mounted to a conductive pad 56 that forms an electrical connection with the actuator 28.

The actuator 28 includes an active first beam 58 arranged on a passive second beam 60. In an embodiment, both beams 58, 60 are composed of a conductive ceramic material such as titanium nitrate (TiN) or include a conductive ceramic material such as titanium nitrate (TiN).

Both beams 58, 60 have a first end fixed to the anchor 54 and an opposite end connected to the arm 26. When a current is caused to flow through the active beam 58, thermal expansion of the beam 58 occurs. Since the passive beam 60 without current flow does not expand at the same rate, as shown in FIG. 3, a bending moment occurs so that the arm 26 and the nozzle 22 are connected to the substrate. Displaced downward toward 16). This causes the ejection of ink through the nozzle opening 24, as shown at 62 in FIG. When the heat source is removed from the active beam 58 by blocking the flow of current, the nozzle 22 returns to the stop position, as shown in FIG. When the nozzle 22 returns to the stop position, as shown at 66 in FIG. 4, the neck of the ink drop is cut to form the ink drop 64. FIG. The ink droplets 64 travel to a print medium such as paper. As a result of the formation of the ink droplet 64, as shown by 68 of FIG. 4, a "minus" meniscus is formed. The “minus” meniscus 68 draws ink into the nozzle chamber 34 such that a new meniscus 38 (FIG. 2) is immediately formed for the next ejection of ink droplets from the nozzle assembly 10. 40) flows in.

5 and 6, the nozzle array 14 will be described in more detail. The array 14 is for a four color printhead. Thus, the array 14 comprises four groups of nozzle assemblies, each group for a separate color. Each group 70 has a nozzle assembly 10 arranged in two rows 72, 74. One of each group 70 is shown in more detail in FIG. 6.

In order to facilitate close packing of the nozzle assembly 10 in rows 72 and 74, the nozzle assembly 10 in row 74 is offset relative to the nozzle assembly 10 in row 72. Or staggered. In addition, the nozzle assemblies 10 in row 72 are mutually connected so that the lever arms 26 of the nozzle assemblies 10 in row 74 pass between adjacent nozzles 22 of the assembly 10 in row 72. Far enough away. Each nozzle assembly 10 is approximately dumbbell shaped so that the nozzles 22 in row 72 are positioned between the nozzles 22 and the actuators 28 of adjacent nozzle assemblies 10 in row 74. It should be noted that

Further, in order to facilitate the dense packing of the nozzles 22 in rows 72 and 74, each nozzle 22 has a substantially hexagonal shape.

It will be sufficiently appreciated that when the nozzle 22 is displaced towards the substrate 16, the ink is ejected slightly off the vertical, because the nozzle opening 24 makes a slight angle to the nozzle chamber 34. will be. It is an advantage of the arrangements shown in FIGS. 5 and 6 that the actuators 28 of the nozzle assemblies of rows 72 and 74 extend in one side, ie in the same direction, of rows 72 and 74. Therefore, the ink is ejected from the nozzle 22 in the row 72, and the ink ejected from the nozzle 22 in the row 74 are offset at the same angle with each other, thereby increasing the print quality.

In addition, as shown in FIG. 5, the substrate 16 has a bond pad 76 arranged thereon, the bond pad 76 via the pad 56, An electrical connection is provided to the actuator 28 of the nozzle assembly 10. This electrical connection is formed by the CMOS layer (not shown).

Referring to Fig. 7, an expanded view of the present invention is shown. With reference to the previous drawings, unless otherwise indicated, like reference numerals refer to like parts.

In this expanded view, nozzle protection means 80 is mounted on the substrate 16 of the array 14. The nozzle protection means 80 includes a body portion 82 through which the plurality of passages 84 pass. The passageway 84 is the nozzle opening of the nozzle assembly 10 of the array 14 such that when ink is ejected from one of the nozzle openings 24, the ink passes through the associated passageway before it hits the print medium. Match with (24) (in register).

The body portion 82 is mounted at a distance from the nozzle assembly 10 by a limb or strut 86. One of the struts 86 has an air inlet opening 88 therein.

In use, when the array 14 is in operation, air is filled through the inlet opening 88 to be forced through the passageway 84 with ink passing through the passageway 84.

When the air is filled through the passageway 84 at a speed different from the speed of the ink drop 64, the ink does not enter the air. For example, the ink droplet 64 is ejected from the nozzle 22 at a speed of approximately 3 m / s. The air is filled through the passageway 84 at a rate of approximately 1 m / s.

The purpose of the air is to keep the passageway 84 free of debris. There is a risk that foreign matter such as dust particles may fall on the nozzle assembly 10 and adversely affect its function. By providing the air inlet opening 88 in the nozzle protector 80 this problem is considerably solved.

8 to 10, a process of manufacturing the nozzle assembly 10 will be described.

First, the dielectric layer 18 is deposited on the surface of the wafer 16 with the silicon substrate or wafer 16. The dielectric layer 18 is in the form of approximately 1.5 micron CVD oxide. A resist is spun in the layer 18. The layer 18 is brought into contact with the mask 100 and then developed.

After development, the layer 18 is plasma etched down to the silicon layer 16. The resist is then removed and the layer 18 is washed. This step forms the ink inlet hole 42.

In FIG. 8B, approximately 0.8 micron of aluminum 102 is deposited on the layer 18. The resist is spun and aluminum 102 is brought into contact with the mask 104 and developed. The aluminum 102 is plasma etched down to the oxide layer 18, the resist is removed, and the device is cleaned. In this process, a bond pad is provided and the inkjet actuators 28 are connected to each other. By such a connection, an NMOS drive transistor and a power plane are connected to each other on a CMOS layer (not shown).

Approximately 0.5 micron PECVD nitride is deposited into the CMOS passivation layer 20. The resist is spun and the layer 20 is contacted with the mask 106 and then developed. After development, the nitride is plasma etched down to the aluminum layer 102 and down to the silicon layer 16 at the inlet hole 42 site. The resist is removed and the device is cleaned.

Layer 108 made of sacrificial material is spin treated to layer 20. The layer 108 is a 6 micron photo-sensitive polyimide or a high temperature resist of approximately 4 microns. The layer 108 is softbaked and then contacted with the mask 110 and then developed. The layer 108 is hardbake at 400 ° C. for one hour when made of polyimide, or hard baked at 300 ° C. or higher when the layer 108 is a high temperature anticorrosive. It should be noted in the drawings that distortion along the pattern of the polyimide layer 108 caused by shrinkage is taken into account in the design of the mask 110.

In the next step, as shown in FIG. 8E, a second sacrificial layer 112 is applied. The layer 112 is a 2 μm photosensitive polyimide that is spun or a high temperature resist of approximately 1.3 μm. The layer 112 is softbaked and in contact with the mask 114. After contacting the mask 114, the layer 112 is developed. If the layer 112 is polyimide, the layer 112 is hardbaked at 400 ° C. for approximately one hour. If layer 112 is a resist, it is hardbaked at 300 ° C. or higher for approximately one hour.

Next, a 0.2 micron multilayer metal layer is deposited. Part of this layer 116 forms the non-active beam 60 of the actuator 28.

The layer 116 is formed by sprinkling 1,000 ns of titanium nitride (TiN) at about 300 ° C. and then splicing 50 ns of tantalum nitride (TaN). After sprinkling 1,000 ns of TiN, sprinkle 50 ns of TaN and 1,000 ns of TiN.

Other materials that can be used instead of TiN are TiB ₂ , MoSi ₂ or (Ti, Al) N.

Then, the layer 116 is in contact with the mask 118, developed, and plasma etched into the layer 112, and the resist applied to the layer 116 does not remove the cured layer 108 or 112. Be careful not to wet strip.

The third sacrificial layer 120 is applied by spinning 4 μm photosensitive polyimide or high temperature resist of approximately 2.6 μm. The layer 120 is softbaked and then contacted with the mask 122. The exposed layer is then developed and then hardbaked. In the case of polyimide, the layer 120 is hardbaked at 400 ° C. for approximately one hour, or at least 300 ° C. if the layer 120 comprises resist.

A second multiple metal layer 124 is applied to the layer 120. The components of the layer 124 are the same as the layer 116 and are applied in the same way. It is noted that layers 116 and 124 are both electrically conductive layers.

The layer 124 is in contact with the mask 126 and then developed. After the layer 124 is plasma etched down to the polyimide or resist layer 120, the resist applied to the layer 124 is wet removed carefully to avoid removing the cured layer 108, 112, or 120. It is noted that the remainder of the layer 124 forms the active passive 58 of the actuator 28.

The fourth sacrificial layer 128 is applied by spinning 4 μm photosensitive polyimide or high temperature resist of approximately 2.6 μm. The layer 128 is softbaked, contacted with the mask 130, and then developed to leave an island portion, as shown in FIG. 9K. The remainder of layer 128 is hardbaked at 400 ° C. for approximately one hour for polyimide and at 300 ° C. or higher for anticorrosive.

As shown in FIG. 8L, a dielectric layer 132 having a high Young's modulus is deposited. The layer 132 is composed of approximately 1 μm silicon nitride or aluminum oxide. The layer 132 is deposited at temperatures below the hard bake temperatures of the sacrificial layers 108, 112, 120, and 128. The main properties required for this dielectric layer 132 are high modulus of elasticity, chemical inertness and good adhesion to TiN.

The fifth sacrificial layer 134 is applied by spin to 2 μm photosensitive polyimide or approximately 1.3 μm high temperature resist. The layer 134 is softbaked, contacted to the mask 136 and developed. The remainder of layer 134 is then hardbaked at 400 ° C. for one hour for polyimide and at 300 ° C. or higher for anticorrosive.

The dielectric layer 132 is plasma etched down to the sacrificial layer 128, taking care not to remove the sacrificial layer 134.

This step forms the nozzle opening 24, the lever arm 26 and the anchor 54 of the nozzle assembly 10.

Dielectric layer 138 with a high Young's modulus is deposited. The layer 138 is formed by depositing 0.2 μm of silicon nitride or aluminum oxide at a temperature below the hard bake temperature of the sacrificial layers 108, 112, 120, and 128.

Then, as shown in FIG. 8P, the layer 138 is plasma etched anisotropically to a depth of 0.35 microns. This etching is used to remove the dielectric material from all surfaces except the sidewalls of the dielectric layer 132 and the sacrificial layer 134. This step forms the nozzle rim 36 around the nozzle opening 24, which "binds" the meniscus of the ink, as described above.

An ultraviolet (UV) emitting tape 140 is applied. A 4 μm resist is spun on the back of the silicon wafer 16. The wafer 16 contacts the mask 142 to etch the wafer 16 again to form the ink inlet channel 48. Resist is then removed from the wafer 16.

A UV emitting tape (not shown) is additionally applied to the back of the wafer 16 and the tape 140 is removed. As shown in FIGS. 8R and 9R, the sacrificial layers 108, 112, 120, 128 and 134 are removed in the oxygen plasma to provide the final nozzle assembly 10. For convenience of reference, the reference numerals used in these two figures are the same as the reference numerals used in FIG. 1 to indicate the relevant parts of the nozzle assembly 10. 11 and 12 show the operation of the nozzle assembly 10 manufactured according to the procedure described above with reference to FIGS. 8 and 9. These figures correspond to FIGS. 2 to 4.

It will be appreciated by those skilled in the art that various changes and / or modifications can be made to the present invention as shown in the specific embodiments above without departing from the spirit or scope of the invention as broadly described. Therefore, this embodiment is to be considered in various respects as illustrative and not restrictive.

Claims (7)

A plurality of nozzle assemblies, each nozzle assembly including an ink jet nozzle and an actuator, and a connecting member interconnecting the nozzle and the actuator, wherein the nozzle assembly comprises nozzles of one row of assemblies; Arranged in rows, the one row being positioned between the connecting members of adjacent nozzle assemblies in the other row and the actuators of the two rows of assemblies arranged on the same side of the rows; Head nozzle array. The method of claim 1, And the nozzles of each assembly are movable and displaced by an associated actuator for performing ink ejection. The method of claim 2, The actuator of each assembly is a thermal bend actuator, and the connecting member is in the form of an arm, the arm having one end extending therefrom and connected to the actuator, the opposite end and the movable nozzle fixed thereto. An inkjet printhead nozzle array. The method of claim 1, And the other row of actuators are received between the row of connecting members. The method of claim 1, The nozzle of the assembly is an inkjet printhead nozzle array, characterized in that formed to facilitate the close packing of the nozzle. The method of claim 5, And the nozzles are formed in an almost hexagonal shape. The method of claim 1, Wherein the printhead is a multicolor printhead, each color having two rows of nozzle assemblies associated therewith, and the actuators in all rows extend in the same direction.