KR20010021415A - Asymmetric ink emitting orifices for improved inkjet drop formation - Google Patents

Abstract

PURPOSE: Print head for an ink-jet printer and method of manufacturing the same are provided to reduce a spray and improve an ink drop traces by using an orifice which is formed in an asymmetrical sandglass shape. CONSTITUTION: An orifice plate includes an orifice which is extended from the first surface opposite to an ink ejector to the second surface substantially parallel to the first surface. The orifice has a hole(803) on the second surface. The hole(803) comprises boundaries which are intersected for defining the outer periphery of the hole(803). The first boundary is a segment(807) which has the first radius(rc) and the first center(805). The second boundary is a segment(813) which has the second radius(rH1) and the second center(815). The third boundary is a segment(809) which has the first radius(rc) and the first center(805). And, the fourth boundary is a segment(811) which has the third radius(rH2) and the third center(819). An acute angle between the first line from the first center to the second center and the second line from the first center to the third center is in the range of 0 degree to 20 degree.

Description

Printhead for inkjet printer and manufacturing method therefor {ASYMMETRIC INK EMITTING ORIFICES FOR IMPROVED INKJET DROP FORMATION}

BACKGROUND OF THE INVENTION Field of the Invention The present invention generally relates to inkjet printer printheads with improved orifice designs, and more particularly to printhead orifice designs with apertures having ink spray reduction characteristics and improved trajectory error characteristics.

Inkjet printers form text and images on media such as paper by controlled release of ink droplets so that the droplets drop at desired locations on the media. In its simplest form, such a printer is a mechanism that moves and places ink droplets in place on a medium so that ink droplets can be placed on the medium, print cartridges that control ink flow and release the ink droplets on the medium, as appropriate control hardware and software. Can be conceptualized. Conventional print cartridges for inkjet printers include an ink receiver for storing and supplying ink as needed, and a printhead for heating and ejecting ink droplets when oriented by the print control software. Generally, a printhead is a laminate structure having a semiconductor base, a barrier material forming an honeycomb with an ink flow channel, and an orifice plate perforated with small holes or orifices arranged in a pattern in which ink droplets are ejected.

In another embodiment of the inkjet printer, the explosion mechanism consists of a plurality of resistors formed on a semiconductor substrate, each coupled to one of several orifices of the orifice plate and one of a plurality of ink firing chambers formed on the blocking layer. Each heater resistor allows each resistor to be coupled to the printer's control software so that each resistor is energized independently and suddenly bubbles a portion of the ink into the droplets, which are then ejected from the opiris with droplets of ink. Ink flows into the firing chamber formed in the blocking layer around each heater resistor and awaits energization of the heater resistor. Following the release of the ink droplets and the collapse of the ink bubbles, the ink is filled in the firing chamber to the point where the meniscus is formed in the orifice. Both the speed and the ink meniscus kinetics of the ink filling the firing chamber by the foam and shrinkage in the barrier layer channel through which the ink flows to fill the firing chamber. In addition, details of the printer, print cartridge and print head shrinkage may be found in Hewlett-Packard Journal Volume 36, No. 5 May 1985 and Hewlett-Packard Journal Volume 45, No. 1 February 1994.

One of the problems faced by designers of print cartridges is achieving high print speeds while maintaining good print quality. When the droplet is released from the orifice due to the rapid boiling of the ink inside the firing chamber, the maximum mass of ejected ink is concentrated in the droplet towards the medium. However, a small portion of the ink that is released remains with the tail extending from the drop to the orifice surface opening. The speed of the ink found with the tail is generally slower than the speed of the ink found in the droplets so that sometimes during the trajectory of the droplets, most tails are aggravated from the droplets. A portion of the ink of the severe tail binds to the ejection droplets or remains a variant of the droplets to roughen the edges of the print. A portion of the ink discharged to the tail is returned to the printhead to form a puddle on the surface of the orifice plate of the printhead. Some of the heavily tailed ink forms subdroplets (“sprays”) that randomly move and spread in the general direction of the ink droplets. This spray often drops on the media to form a background of ink bleeding.

To reduce the detrimental effects of this spray, others have slowed the print job, but have also experienced a reduction in the number of pages the printer can print at a given time. The spray problem is solved by optimizing the structure or geometry of the ink firing chamber and the associated ink is fed into the conduit of the barrier layer. Orifice geometry also affects spraying, which is disclosed in US patent application Ser. No. 08 / 608,923, filed "WebSymmetry," 29 February 1996, entitled "Asymmetric Printhead Orifice."

The conventional method of manufacturing the orifice plate uses the electroless plating method on the prefabricated mandrel. This mandrel is shown in FIG. 1 (not the same accumulation) and the substrate 101 has at least one plane made of silicon or glass. A conductive layer 103, which is generally a chromium or stainless steel film, is deposited on the plane of the substrate 101. Vacuum deposition methods, such as planar magnetron methods, may be used to deposit this conductive film 103. Another vacuum deposition method may be used to deposit the insulating layer 105, which is generally silicon nitride, and is deposited by a vacuum deposition method such as a plasma enhanced chemical vapor deposition method. The insulating layer 105 is preferably very thin with a thickness of approximately 0.30 μm. The insulating layer 105 is covered with a photoresist mask and employs a plasma etching technique that is exposed to UV light and removes most of the insulating layer except the insulating material "button" at a preselected location on the conductive layer 103. Of course, these positions are predetermined with respective orifice positions of the orifice plate formed on the upper mandrel.

This recyclable mandrel is disposed in an electroforming bath in which the conductive layer 103 is the cathode and the base material, usually nickel, is the anode. During the electroforming process, nickel metal is moved from the positive electrode to the negative electrode so that nickel (shown as layer 107) is attached to the conductive region of the conductive layer 103. Since the nickel metal plate is uniformly plated from each electroplating of the mandrel, when the surface of the insulating button 105 touches, nickel overplats the insulating layer in a uniform and predictable pattern. Variables of the plating process including the plating time are carefully controlled so that openings of the nickel layer 107 formed on the insulating layer button 105 are formed in the insulating surface with a predetermined diameter (particularly about 45 mu m). This diameter is generally 1/3 to 1/5 of the diameter of the insulating layer button 105, so that the nickel upper layer 107 having an opening in the inner surface of the orifice plate of diameter d2 is the orifice of the outer surface of the orifice plate. It is approximately three to five times the aperture diameter d1 for the holes. At the end of the electroless plating process, the newly formed orifice plate is removed from the mandrel and gold plated for corrosion resistance of the orifice. Additional descriptions of metal orifice plates can be found in US Pat. No. 4,773,971, US Pat. No. 5,167,776, US Pat. No. 5,443,713 and US Pat. No. 5,560,837, all assigned to the assignee of the present invention.

Improperly oriented ink droplets and incidental droplets and sprays undesirably form malicious text and images on inkjet print media. Reduction in irregular trajectories due to irregular drops from the ejection orifice side and spray reduction due to drop tail blocking is desirable.

The present invention relates to a printhead for an ink jet printer using an ink ejector to eject ink from an orifice of an orifice plate. The orifice plate has at least one orifice extending through the orifice plate from the first surface of the orifice plate opposite the ink ejector to the second surface of the orifice plate substantially parallel to the first surface. The orifice has a hole in the second surface, which hole consists of at least two intersecting edges defining the hole main surface. The first edge includes a first arc segment having a first radius and a first center disposed around the hole. The second edge, consisting of a second arc segment having a second radius and a second center, is arranged outside the outer circumference of the hole.

1 is a cross-sectional view of an orifice plate forming a mandrel and an orifice plate formed on the mandrel,

2 is a cross-sectional view of a conventional printhead showing one ink firing chamber;

3 is a plan view of an outer surface of an orifice plate of a conventional printhead;

4 is a cross-sectional view of a conventional printhead showing the explosion of ink droplets,

5 is a theoretical model of a droplet meniscus system, which may be useful for understanding the performance of the present invention;

6 is a reproduction of the detrimental effects of sprays and long drop tails on print media,

7A and 7B are plan views of the outer surface of the orifice plate showing the orifice surface hole;

8A and 8B are plan views of an orifice plate surface showing an orifice surface hole that may be employed in the present invention;

9A and 9B are regeneration views of the spray effect on the print media and enhancements provided by the present invention;

10 is a diagram of a technique for forming an orifice hole that may be employed in the present invention;

11 is a diagram of a technique for forming an orifice hole that may be employed in the present invention;

12 is a plan view of an outer surface of an orifice plate showing orifice surface holes and orifice bores relative to the ink firing chamber, as may be employed in the present invention.

Brief description of the main parts of the drawing

107: orifice plate 803: orifice opening

805: 1st center 807: 1st segment

809: No. 3 Segment 811: No. 4 Segment

815: second center 819: third center

Irregular drop trajectories and excessive spray, in which trajectories can be deflected from one direction of the ejection orifice, are reduced by employing the present invention using asymmetric orifice holes.

A cross-sectional view of a conventional printhead is shown in FIG. The thin film resistor 201 is formed on the surface of the semiconductor substrate 203 and is connected to an electrical input unit by metallization on the surface of the semiconductor substrate 203. In addition, although several layers may be disposed above the heater resistor 201 to defend against chemical and mechanical initiation, they are not shown in FIG. 2 for simplicity. The barrier material layer 205 is selectively disposed on the surface of the silicon substrate 203 (or an upper layer thereof) to leave an opening or ink firing chamber 207 around the heater resistor 201 and ink to the heater resistor 201. May be accumulated in the firing chamber prior to activation and ejection of ink through the orifice 209. The barrier material of the barrier layer 205 is typically Parad® available from E.I.DuPont De Nemours and Company and its equivalents. Orifice 209 is a hole in orifice plate 107 that extends from the inner surface of orifice plate to the outer surface of orifice plate and may be formed as part of orifice plate as described above.

3 is a plan view of the printhead (A-A cross-sectional view of FIG. 2) when viewing the orifice 209 from the outer surface 213 of the orifice plate 107. The ink supply channel 301 transfers ink from the larger ink source (not shown) to the ink firing chamber in the blocking layer 205. 4 shows the shape of the ink drop 401 22 microseconds after the ink is ejected from the orifice 209. In conventional orifice plates (circular orifice holes are used), the ink droplets 401 hold a long tail 403 that can be shown to extend in reverse direction towards at least the orifice 209 of the orifice plate 107.

After the droplet 401 exits the orifice plate and the ink bubble, which is a bubble of the released droplet, collapses, capillary force pulls ink from the ink source through the ink supply channel 301. In a less wet system, the ink flows back into the firing chamber quickly enough to overflow the firing chamber 207 to form a bulky meniscus. The meniscus vibrates near the equilibrium position several cycles before stabilization. The retracted meniscus reduces the volume if the droplets are released during some of the cycles. Printhead designers improve and optimize the damping of ink refill systems and meniscus systems by increasing the fluid resistance of the ink fill channel. In general, this improvement has been achieved by lengthening the ink refill channel, reducing the cross-sectional area of the ink refill channel, and increasing the viscosity of the ink. Increasing the ink refill fluid resistance slows refill time and slows Paul's injection rate and printing speed.

A simple analysis of the meniscus system is the same as the mechanical model shown in FIG. 5, with a spring 505 having a spring constant K whose mass 501 coincides with the mass of the discharge droplet is inversely proportional to the effective radius of the orifice. By the fixed structure 503. Mass 501 is coupled to fixed structure 503 by damping function 507 related to channel fluid resistance and other ink channel characteristics. In the configuration of the present invention, the emissive weight mass 501 is proportional to the diameter of the orifice. Thus, if one wishes to control the characteristic value and the performance of the meniscus, the damping factor of the damping function 507 may be adjusted by optimizing the ink channel with the mechanical model or by adjusting the spring constant of the spring 505. .

When the droplet 401 is released from the orifice, most of the droplet mass is contained at the tip of the droplet 401 and the maximum velocity is found at this mass. The remaining tail 403 has a minimum ink mass and has a velocity distribution from a speed approximately equal to the speed of the ink drop head near the ink drop head to a speed below the ink speed found in the ink drop head closest to the orifice hole. At some point during the movement of the droplets, the ink of the tail is drawn at the point where the tail is separated from the droplets. Some of the ink remaining in the tail is drawn back toward the printhead orifice plate 107, which generally forms a puddle of ink around the orifice. These ink puddles later cause misalignment of the ink droplets to determine the grade of the print quality. The other part of the ink drop tail is absorbed by the ink drop head before the ink drop is deposited on the medium. Finally, some of the ink found in the ink drop ring does not return to the printhead or remain or dwell in the ink drop, but forms a fine spray of the lower drop that spreads in an irregular direction. A portion of this spray arrives on the medium when printing starts to roughen the dot edges formed by ink droplets and places unwanted spots on the medium that reduce the sharpness of the desired print. This unwanted result is shown in the magnified presentation of the printing dots of FIG. 6.

The exit area of the orifice hole 209 relative to the external environment is determined to define the weight of the ejected ink drop. Determine the restoring force of the meniscus (constant K in the model) to be determined in part near the edge of the orifice hole. Thus, in order to increase the stiffness of the meniscus, the sides and the opening of the orifice bore hole are as close to each other as possible. Of course, this contradicts the conditions for determining the desired drop weight of the drop (determined at the exit area of the orifice). The greater the restoring force on the meniscus provided by the non-circular geometry, the faster the ink droplet tail disappears closer to the orifice plate.

Some non-circular orifices that may be used to reduce spray are elongated holes with long and short axis, the long axis being larger than the short axis and these axes are parallel to the outer surface of the orifice plate. Such elongated structures may be rectangular and may be oval, such as elliptical and "racetrack" structures with parallel sides. Using the area of the orifice holes such as the ink contained in the model number HP51649 A print cartridge (available from the Hewlett-Packard Company) and the area of the orifice opening area used in the HP 51649A cartridge, the desired meniscus stiffness and shortness An ellipse with a long axis shortening ratio representing the ink droplet emission characteristic of the tail was determined to be 2 to 1 to 5 to 1.

7A and 7B are top views of orifice plate outer surfaces illustrating various types of orifice bore hole sizes. FIG. 7A shows the difference in curvature between the outer dimension r and the opening value r ₂ for the firing chamber. For the HP51649 A cartridge, r = 17.5 μ and r ₂ = 45 μ. This provides a hole area (r ² Xπ) in the orifice plate outer surface of 962 μ ² . FIG. 7B shows an elliptical outer orifice opening geometry in which the long axis / short axis ratio is 2 to 1 and the outer area of the orifice opening is maintained at 962 μ ² to maintain a uniform drop drop weight. Therefore, from the elliptical area formula (A = π · a · b), the major and minor axes (a, b) of the ellipse are 28.5 μ and 12.4 μ for the 2: 1 ellipse, respectively.

As stated, the main factor for better tail blocking and subsequent spray reduction properties is the shortened size reduction of the ellipse. In the axial ratio range of 2: 1 to 5: 1, spray reduction is observed. One disadvantage described above is that the elliptical orifice surface opening has a larger opening corresponding to the inner surface of the orifice plate (in the ink firing chamber). These inner openings will overlap and interfere if the orifices are closely spaced to enhance the printed image. This interference is called from the firing chamber to the adjacent firing chamber in the form of ink to provide a faint but detrimental effect.

To solve the interference problem, the ellipse is deformed in the long axis direction, essentially forming a crescent or quadrant shape. The short axis size is maintained and the crescent shape shortens the effective long axis so that the entire orifice opening area remains constant. Appropriate spray reduction is continually achieved using the crescent orifice opening shape. However, the crescent shape introduces another problem to the print quality achieved with this type of printhead. The trajectory of the ink droplets leaving the orifice plate is not perpendicular to the orifice plate surface and is inclined from the vertical toward the negative curvature direction of the curved surface of the orifice opening.

In order to solve the trajectory problem of the crescent orifice hole shape, a branch of the crescent moon in which other shapes providing symmetry face each other are formed by overlapping into two crescent shapes. This shape is shown in Figure 8a. This modified orifice hole shape becomes a "hourglass" shape. In one embodiment, the strain short axis b _H is set to 26 μm and the strain long axis a _H is set to 69 μm. The edge defining the shortening of strain for this embodiment has a radius of curvature r _H of approximately 47 μm. This orifice hole shape maintains a narrow uniaxial opening and reduces the required major spindle size required for the fixed orifice opening area. The reduced major axis achieves orifice spacing closer than that achieved by the same orifice hole area. In addition, the hourglass orifice hole shape provides symmetry with respect to long and short axis and reduces ink droplet trajectory error problem. The improvement provided by non-circular orifice openings compared to conventional circular openings can be understood when comparing FIGS. 9A and 9B. The enlarged letters in FIG. 9B show some foreign droplets that appear in the printout of FIG. 9A.

Referring to FIG. 8B, in order to further reduce the trajectory error, a reliable cutoff point of the tail is achieved in an hourglass shape with an asymmetrical orifice opening with respect to the shortening of deformation. The asymmetric hourglass orifice opening is shown as orifice opening 803 in FIG. 8B. The hourglass shape of the orifice opening 803 constitutes an orifice opening edge on the outer surface of the orifice plate. In a preferred embodiment, the peripheral shape of the orifice opening is formed from two arc segments having a radius 805 and a common radius size r _c , while the first arc segment 807 has two arc segments 809 ( Disposed opposite to the first arc segment. The hourglass-shaped perimeter of the orifice hole 803 also includes two arc segments 811, 813 that join the end points 807, 809 of adjacent segments. The arc segment 813 is disposed within the radius size r _HI and the protrusion 817 of the orifice hole formed in the interior, surface, and elsewhere of the orifice plate adjacent to the ink ejector, but the radius 815 disposed outside the periphery of the hourglass. Has a center point. The arc segment 811 also has a radius size r _H2 and a center point of the radius 819 in the other projection 821 of the orifice hole of the inner surface. It is a feature of the present invention that the center 815 is disposed proximate to the opposite side of the orifice from the center 819. In a preferred embodiment, the line connecting center 805 and center 815 intersects the line connecting center 805 and center 819 to form an acute angle θ. The acute angle θ formed between these two lines is adjusted in the range of 0 ° to 20 ° and is preferably approximately 5 °. Thus, the orifice hole 803 formed by electroplating on the outer orifice plate surface has an asymmetric hourglass orifice hole and separates the orifice hole on the inner orifice plate surface consisting of two elongated arc segments separated by two protrusions and having a common center. Have The ink drop tail preferentially disappears from the narrower end (ie, the shorter arc segment 809) and provides a reliable location of tail shorts and sprays. Uniform trajectories are generated for drops ejected from each orifice employing an asymmetric hourglass shape.

As mentioned above, the orifice plate is generally formed by electroplating nickel or similar metal on the mandrel and then plated with a chemical resistant material such as gold. It is already known to use non-conductive buttons as shapes (round orifice holes) with the desired results. However, it can be seen that a button having a less complicated shape than the hourglass shape can be used to form an hourglass shaped orifice opening. During electroplating the orifice plate, the metal grows uniformly in the respective effective direction from the conducting surface (the surface of itself) and the details of the non-conductive button shape are covered up by growing the base metal. Likewise, the details of the button shape can be transformed into other shapes as a whole as the base metal grows. Referring now to FIG. 1, the base metal 107 grows over the top surface of the nonconductive insulated button 105. When shown in plan view, details of the aslines of the button 107 may be deformed or hidden into other shapes as the base metal 107 grows over the top surface of the insulated button 105.

Analytical techniques using populations of circles having a uniform diameter for the desired base metal growth can be seen that they can be placed on the same surface and tangentially placed on the outer outline of the desired all-piece shape. The circumferential point of a circle facing the tangent and sharing a diameter when combined at different similarities of a binary group reveals the shape of the non-conductive button. Another procedure uses an arc of radius drawn with all points or representative points outside the outline of the starting shape. The end point of the radius of each arc (perpendicular to the line tangentially drawn to the point of the starting outline) defines the point of the orifice shape that is the result after the plating process is completed. Referring to FIG. 10, a technique of using a group of circles can be seen.

In FIG. 10, the hourglass shape of the all-piece hole is identified by reference numeral 1001. A circle of circles having a radius that matches the desired growth of the base metal is represented by circle 1003. The outline of the non-conductive button is shown at 1005. Each circle of the circle group abuts the hourglass orifice shape at a point along the edge of the hourglass shape. Taking points that cross the diameter of each circle directly and combining them results in the shape of a non-conductive button. When processing a more complex orifice shape, it can be seen that the shape of the non-conductive button should not be the same as the orifice shape. In the branches of the hourglass shape 1001, it can be seen that the number of circles required to define the shape is reduced.

11 shows the necessary members required to form orifice opening 1001. Combining the circumferential points opposite the contacts, it is possible to obtain the minimum button outline needed to produce the desired hourglass orifice opening. These outline configurations have arcs 1101 and 1103 to form the end points of the long axis and parabolic portions 1105 and 1107 to form the edges forming the end points of the minor axis. If the remaining portion of the button outline is no closer to the desired orifice shape than the diameter of the circle, the hourglass orifice shape formed by electroplating the orifice plate will be independent of the button outline other than the particular arc and bubbling.

This independence of the outline is used in embodiments of the present invention to improve the adhesion of the orifice plate to the barrier and allow the maximum volume of ink to fill the firing chamber. 12 shows the printhead obtained when the non-conductive mandrel button shape is partially independent of the orifice surface hole shape. Although orifice hole 1101 is disposed on the outer surface of the orifice plate and the button shape is disposed on the inner surface of the orifice plate, orifice hole 1001 and button shape 1201 are shown in solid lines for simplicity. When the orifice hole starts in the ink firing chamber and crosses the opening of the surface of the orifice plate, the orifice bore changes from button shape 1201 to hourglass shaped hole 1001. In this embodiment, the construction of the barrier layer material is shown by broken lines. An island of blocking material 1203 divides the ink inlet to firing chamber 1205 into two ink channels 1207, 1209 and the remainder of firing chamber 1205 is formed of blocking materials 1211, 1213, 1215, and the like. It is defined as a wall. The area of contact between the blocking layer material and the orifice plate is increased in the area around the blocking island 1203 (shown by the additional break line representing the virtual one button outline). This increase in contact area is achieved by the square of the button shape of the portion that may be circular, so that it better matches the square of the barrier material and provides a rectangular cross section on the substrate that does not change even when misalignment of the orifice plate occurs. The square also increases the ink volume of the firing chamber.

Thus, the present invention utilizes an asymmetric hourglass-shaped orifice hole shape that provides reduced ejection ink droplets with reduced spray and improved ink drop trajectory.

The present invention provides a reduced spray printhead having an orifice from which ink is ejected by the ink ejector, wherein the orifice employs an asymmetric sandblast-shaped hole 803 on the outer surface such that the ejected ink droplets are at the narrow end of the orifice hole. To be blocked.

Claims (10)

A printhead for an inkjet printer having an orifice through which ink is discharged, With ink ejector, An orifice plate 107 having an orifice extending through an orifice plate from a first surface of the orifice plate opposite the ejector to a second surface of the orifice plate substantially parallel to the first surface, the orifice being the second Having a hole 803 in the surface, the hole in the second surface of the orifice consists of at least two intersecting edges defining the outer periphery of the hole, the first edge being a first radius disposed in the periphery of the hole (r _C ) and a first arc segment 807 having a first center 805, the second edge of which is a second radius r _H1 and a second center ( A printhead for an inkjet printer comprising an orifice plate (107) composed of 815. The method of claim 1, And a third arc segment (809) having said first radius and said first center (805). The method of claim 1, And a fourth arc segment (811) spaced from said second center and having a third radius (r _H2 ) and a third center (819) disposed outside the outer periphery of said aperture. The method of claim 3, wherein The first line joining the first center and the second center forms an acute angle with the second line joining the first center and the third center, wherein the acute angle has a value ranging from 0 ° to 20 °. Frithead for printers. In a method of operating a printhead for an inkjet printer employing an orifice from which ink is discharged, Speeding up the ink mass, Ejecting the ink mass from an orifice having a hole 803 in the surface of the orifice plate 107, wherein the hole in the surface consists of at least two crossing edges defining an outer periphery of the hole, the first edge being A first arc segment 807 having a first radius r _C disposed within the periphery of the hole and a first center 805, the second edge of the second radius being disposed outside the periphery of the hole; r _H1 ) and a second arc segment having a second center (815), the method of operating a printhead for an inkjet printer. In the printhead manufacturing method for an inkjet printer, Forming an orifice plate 107 having a first surface and a second surface essentially parallel to the first surface and at least one orifice extending through the orifice plate from the first surface to the second surface. The orifice has a hole 8030 on the second surface consisting of at least two intersecting edges defining a periphery of the hole, the first edge having a first radius r _C and a first edge disposed within the periphery of the hole. A first arc segment 807 having a first center 805, the second edge being a second arc segment having a second radius r _H1 and a second center 815 disposed outside the periphery of the aperture. Orifice plate 107 forming step consisting of, A method of manufacturing a printhead for an inkjet printer, comprising attaching an ink ejector to a first surface of the orifice plate to eject ink from the openings of at least one orifice. The method of claim 6, And forming the orifice plate further comprises having a third edge in the hole formed by a third arc segment (809) having the first radius and the first center. The method of claim 6, The orifice plate forming step further includes the step of having a fourth arc segment 811 formed of a third radius r _H2 and a third center 819 spaced from the second center and disposed outside the outer circumference of the hole. Printhead manufacturing method for an inkjet printer containing. The method of claim 8, The forming of the first, second, third and fourth arc segments may include forming a first line joining the first center and the second center to an acute angle with a second line joining the first center and the third center. Forming a first center, a second center, and a third center such that the acute angle has a numerical value ranging from 0 ° to 20 °. The method of claim 6, Forming a hole in the first surface, the hole having an edge composed of at least two arc segments defining an outer periphery of the hole in the first surface, the at least two first surface arc segments having a common radius; A method of manufacturing a printhead for a printer having a common center, wherein the common center is disposed within a hole outer periphery of the first surface, each of the two first surfaces being larger than the first arc segment.