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A printhead having reduced spray includes orifi from which ink is expelled by an ink ejector. The orifi employ an aperture at the outer surface of the orifice plate having an asymmetrical hourglass shape to cause the expelled ink drop to break off at the narrow end of the orifice aperture.
1. A printhead for an inkjet printer including orifi from which ink is expelled, comprising:
an ink ejector; and
an orifice plate having an orifice extending through said orifice plate from a first surface of said orifice plate opposite said ink ejector to a second surface of said orifice plate essentially parallel to said first surface, said orifice including an aperture at said second surface, said aperture in said second surface of said orifice comprised of at least two intersecting edges defining a periphery of said aperture, a first edge comprising a first arc segment having a first radius and a first center disposed within said periphery of said aperture, and a second edge comprising a second arc segment having a second radius and a second center disposed outside said periphery of said aperture, and a third edge comprising a third arc segment having a third radius and a third center disposed outside said periphery of said aperture and spaced apart from said second center.
2. A printhead in accordance with
3. A printhead in accordance with
4. A printhead in accordance with
5. A printhead in accordance with
6. A print cartridge comprising the printhead of
7. A method of operation of a printhead for an inkjet printer which employs orifi from which ink is expelled, comprising the steps of:
imparting a velocity to a mass of ink; and
expelling said mass of ink from an orifice that includes an aperture at a surface of an orifice plate, said aperture in said surface comprised of at least two intersecting edges defining a periphery of said aperture, a first edge comprising a first arc segment having a first radius and a first center disposed within said periphery of said aperture, a second edge comprising a second arc segment having a second radius and a second center disposed outside said periphery of said aperture, and a third edge comprising a third arc segment having a third radius and a third center disposed outside said periphery of said aperture and spaced apart from said second center.
8. A method of manufacturing a printhead for an inkjet printer comprising the steps of:
forming an orifice plate with a first surface and a second surface essentially parallel to said first surface and at least one orifice extending through said orifice plate from said first surface to a second surface, said orifice including an aperture at said second surface comprised of at least two intersecting edges defining a periphery of said aperture, a first edge comprising a first arc segment having a first radius and a first center disposed within said periphery of said aperture, a second edge comprising a second arc segment having a second radius and a second center disposed outside said periphery of said aperture, and a third arc segment formed with a third radius and a third center disposed outside said periphery of said aperture and spaced apart from said second center; and
attaching an ink ejector to said first surface of said orifice plate whereby ink is ejected from said aperture of said at least one orifice.
9. A method in accordance with the method of
10. A method in accordance with the method of
11. A method in accordance with the method of
12. A method in accordance with the method of
13. A method of manufacturing a printhead in accordance with the method of
This patent is a continuation-in-part of U.S. patent application No. 08/805,488 "Reduced Spray Inkjet Printhead Orifice", filed on behalf of Agarwal, et al. on Feb. 25, 1997 now U.S. Pat. No. 6,123,413 which is a continuation-in-part of U.S. patent application No. 08/547,885, "Non-Circular Printhead Orifice", filed on behalf of Weber on Oct. 25, 1995 now still pending and assigned to the assignee of the present invention.
The present invention is generally related to an inkjet printer printhead having an improved orifice design and is more particularly related to a printhead orifice design having an opening with characteristics producing reduced ink spray and improved trajectory error.
An inkjet printer forms characters and images on a medium, such as paper, by expelling droplets of ink in a controlled fashion so that the droplets land in desired locations on the medium. In its simplest form, such a printer can be conceptualized as a mechanism for moving and placing the medium in a position such that the ink droplets can be placed on the medium, a printing cartridge which controls the flow of ink and expels droplets of ink to the medium, and appropriate control hardware and software. A conventional print cartridge for an inkjet printer comprises an ink containment section, which stores and supplies ink as needed, and a printhead, which heats and expels the ink droplets as directed by the printer control software. Typically, the printhead is a laminate structure including a semiconductor base, a barrier material structure which is honeycombed with ink flow channels, and an orifice plate which is perforated with small holes or orifices arranged in a pattern which allows ink droplets to be expelled.
In one variety of inkjet printer the expulsion mechanism consists of a plurality of heater resistors formed in the semiconductor substrate which are each associated with one of a plurality of ink firing chambers formed in the barrier layer and one orifice of a plurality of orifi in the orifice plate. Each of the heater resistors is connected to the controlling software of the printer such that each of the resistors may be independently energized to quickly vaporize a portion of ink into a bubble which subsequently expels a droplet of ink from an orifice. Ink flows into the firing chamber formed in the barrier layer around each heater resistor and awaits energization of the heater resistor. Following ejection of the ink droplet and collapse of the ink bubble, ink refills the firing chamber to the point where a meniscus is formed across the orifice. The form and constrictions in barrier layer channels through which ink flows to refill the firing chamber establish both the speed at which ink refills the firing chamber and the dynamics of the ink meniscus. Further details of printer, print cartridge, and printhead construction may be found in the Hewlett-Packard Journal, Vol. 36, No. 5, May 1985, and in the Hewlett-Packard Journal, Vol. 45, No. 1, February 1994.
One of the problems faced by designers of print cartridges is that of maintaining a high print quality while achieving a high rate of printing speed. When a droplet is expelled from an orifice due to the rapid boiling of the ink inside the firing chamber, most of the mass of the ejected ink is concentrated in the droplet which is directed toward the medium. However, a small portion of the expelled ink resides in a tail extending from the droplet to the surface opening of the orifice. The velocity of the ink found in the tail is generally less than the velocity of the ink found in the droplet so that at some time during the trajectory of the droplet, much of the tail is severed from the droplet. Some of the ink in the severed tail rejoins the expelled droplet or remains as a distortion of the droplet to create rough edges on the printed material. Some of the expelled ink in the tail returns to the printhead, forming puddles on the surface of the orifice plate of the printhead. Some of the ink in the severed tail forms subdroplets ("spray") which travel and spread randomly in the general direction of the ink droplet. This spray often lands on the medium to produce a background of ink haze.
To reduce the detrimental results of spray, others have reduced the speed of the printing operation but have suffered a reduction in the number of pages which a printer can print in a given amount of time. The spray problem has also been addressed by optimizing the architecture or geometry of the ink firing chamber and the associated ink feed conduits in the barrier layer. Orifice geometries also affect spray, see U.S. patent application Ser. No. 08/608,923, "Asymmetric Printhead Orifice" filed on behalf of Weber et al. on Feb. 29, 1996 now still pending.
One conventional method of fabricating an orifice plate utilizes an electroless plating technique on a prefabricated mandrel. Such a mandrel is illustrated in FIG. 1 (which is not drawn to scale), in which a substrate 101 has at least one flat surface constructed of silicon or glass. Disposed on the flat surface of the substrate 101 is a conducting layer 103, generally a film of chromium or stainless steel. A vacuum deposition process, such as the planar magnetron process, may be used to deposit this conductive film 103. Another vacuum deposition process may be used to deposit a dielectric layer 105, which typically is silicon nitride, and is deposed by a vacuum deposition process such as a plasma enhanced chemical vapor deposition process. Dielectric layer 105 is desirably very thin, typically having a thickness of approximately 0.30 μm. Dielectric layer 105 is masked with a photoresist mask, exposed to UV light, and introduced into a plasma etching process which removes most of the dielectric layer except for "buttons" of dielectric material in preselected positions on the conductive layer 103. Of course, these positions are predetermined to be the location of each orifice of the orifice plate which is to be created atop the mandrel.
This reusable mandrel is placed into an electroforming bath in which the conducting layer 103 is established as a cathode while a base material, typically nickel, is established as the anode. During the electroforming process, nickel metal is transferred from the anode to the cathode and the nickel (shown as layer 107) attaches to the conductive areas of the conductive layer 103. Since the nickel metal plates uniformly from each conductive plate of the mandrel, once the surface of the dielectric button 105 is reached, the nickel overplates the dielectric layer in a uniform and predictable pattern. The parameters of the plating process, including the time of plating, are carefully controlled so that the opening of the nickel layer 107 formed over the dielectric layer button 105 is a predetermined diameter (typically about 45 μm) at the dielectric surface. This diameter is usually one third to one fifth the diameter of the dielectric layer button 105 thereby resulting in the top layer of the nickel 107 having an opening at the inner surface of the orifice plate of diameter d2 which is approximately three to five times the diameter of d1 of the opening which will be the orifice aperture at the external surface of the orifice plate. At the completion 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 description of metal orifice plate fabrication may be found in U.S. Pat. Nos. 4,773,971; 5,167,776; 5,443,713; and 5,560,837, each assigned to the assignee of the present invention.
Improperly directed ink drops and satellite droplets and spray undesirably result in a poorer quality of character and image formation on an inkjet printed medium. It is desirable that random trajectory due to drops issuing randomly from sides of the ejecting orifice be reduced and that spray due to drop tail break-off be diminished.
The present invention encompasses a printhead for an inkjet printer which utilizes an ink ejector to expel ink from orifi in an orifice plate. The orifice plate has at least one orifice extending through the orifice plate from a first surface of the orifice plate opposite the ink ejector to a second surface of the orifice plate essentially parallel the first surface. The orifice includes an aperture at the second surface, the aperture comprised of at least two intersecting edges defining a periphery of the aperture. A first edge comprises a first arc segment having a first radius and a first center disposed within the periphery of the aperture. A second edge comprising a second arc segment having a second radius and a second center disposed outside the periphery of the aperture.
FIG. 1 is a cross section of an orifice plate forming mandrel and an orifice plate formed on the mandrel.
FIG. 2 is a cross sectional view of a conventional printhead showing one ink firing chamber.
FIG. 3 is a plan view of the outer surface of the orifice plate of a conventional printhead.
FIG. 4 is a cross sectional view of a conventional printhead illustrating the expulsion of an ink droplet.
FIG. 5 is a theoretical model of the droplet-meniscus system which may be useful in understanding the performance of the present invention.
FIG. 6 is a reproduction of the detrimental effects of spray and elongated droplet tail upon a printed medium.
FIGS. 7A and 7B are plan views from the external surface of the orifice plate showing orifice surface apertures.
FIGS. 8A and 8B are plan views from a surface of the orifice plate showing an orifice surface aperture which may be employed in the present invention.
FIGS. 9A and 9B are reproductions of spray effects upon a printed medium and the improvement of offered by the present invention.
FIG. 10 illustrates a technique of forming an orifice aperture which may be employed in the present invention.
FIG. 11 illustrates a technique of forming an orifice aperture which may be employed in the present invention.
FIG. 12 is a plan view from the external surface of the orifice plate illustrating the orifice surface aperture and orifice bore in relation to an ink firing chamber, as may be employed in the present invention.
Random drop trajectory and excess spray are reduced when employing the present invention as a result of an asymmetric orifice aperture, in which trajectory can be biased to occur in one direction from the ejecting orifice.
A cross section of a conventional printhead is shown in FIG. 2. A thin film resistor 201 is created at the surface of a semiconductor substrate 203 and typically is connected to electrical inputs by way of a metalization (not shown) on the surface of the semiconductor substrate 203. Additionally, various layers offering protection from chemical and mechanical attack may be placed over the heater resistor 201, but are not shown in FIG. 2 for clarity. A layer of barrier material 205 is selectively placed on the surface of the silicon substrate 203 (or layers thereon) thereby leaving an opening or ink firing chamber 207 around the heater resistor 201 so that ink may accumulate in the firing chamber prior to activation of heater resistor 201 and ejection of ink through an orifice 209. The barrier material for barrier layer 205 is conventionally Parad� available from E. I. DuPont De Nemours and Company or equivalent material. The orifice 209 is a hole in the orifice plate 107 extending from the inside surface of the orifice plate to the external surface of the orifice plate and which can be formed as part of the orifice plate as previously described.
FIG. 3 is a top plan view of a conventional printhead (indicating the section A—A of FIG. 2), viewing orifice 209 from the external surface 213 of the orifice plate 107. An ink feed channel 301 is present in the barrier layer 205 to deliver ink to the ink firing chamber from a larger ink source (not shown). FIG. 4 illustrates the configuration of ink in an ink droplet 401 at a time 22 microseconds after the ink has been expelled from the orifice 209. In conventional orifice plates, (in which circular orifice apertures are used) the ink droplet 401 maintains a long tail 403 which can be seen to extend back to at least the orifice 209 in the orifice plate 107.
After the droplet 401 leaves the orifice plate and the bubble of vaporized ink which expelled the droplet collapses, capillary forces draw ink from the ink source through the ink feed channel 301. In an underdamped system, ink rushes back into the firing chamber so rapidly that it overfills the firing chamber 207, thereby creating a bulging meniscus. The meniscus then oscillates about its equilibrium position for several cycles before settling down. Extra ink in the bulging meniscus adds to the volume of an ink droplet should a droplet be expelled while the meniscus is bulging. A retracted meniscus reduces the volume of the droplet should the droplet be expelled during this part of the cycle. Printhead designers have improved and optimized the damping of the ink refill and meniscus system by increasing the fluid resistance of the ink refill channel. Typically this improvement has been accomplished by lengthening the ink refill channel, decreasing the ink refill channel cross section, or by increasing the viscosity of the ink. Such an increase in ink refill fluid resistance often results in slower refill times and a reduced rate of droplet ejection and printing speed.
A simplified analysis of the meniscus system is one such as the mechanical model shown in FIG. 5, in which a mass 501, equivalent to the mass of the expelled droplet, is coupled to a fixed structure 503 by a spring 505 having a spring constant, K, proportional to the reciprocal of the effective radius of the orifice. The mass 501 is also coupled to the fixed structure 503 by a damping function 507 which is related to the channel fluid resistance and other ink channel characteristics. In the present configuration, the drop weight mass 501 is proportional to the diameter of the orifice. Thus, if one desires to control the characteristics and performance of the meniscus, one may adjust the damping factor of the damping function 507 by optimizing the ink channel or adjusting the spring constant of spring 505 in the mechanical model.
When the droplet 401 is ejected from the orifice most of the mass of the droplet is contained in the leading head of the droplet 401 and the greatest velocity is found in this mass. The remaining tail 403 contains a minority of the mass of ink and has a distribution of velocity ranging from nearly the same as the ink droplet head at a location near the ink droplet head to a velocity less than the velocity of the ink found in the ink droplet head and located closest to the orifice aperture. At some time during the transit of the droplet, the ink in the tail is stretched to a point where the tail is broken off from the droplet. A portion of the ink remaining in the tail is pulled back to the printhead orifice plate 107 where it typically forms puddles of ink surrounding the orifice. These ink puddles degrade the quality of the printed material by causing misdirection of subsequent ink droplets. Other parts of the ink droplet tail are absorbed into the ink droplet head prior to the ink droplet being deposited upon the medium. Finally, some of the ink found in the ink droplet tail neither returns to the printhead nor remains with or is absorbed in the ink droplet, but produces a fine spray of subdroplets spreading in a random direction. Some of this spray reaches the medium upon which printing is occurring thereby producing rough edges to the dots formed by the ink droplet and placing undesired spots on the medium which reduces the clarity of the desired printed material. Such an undesired result is shown in the magnified representation of printed dots in FIG. 6.
It has been determined that the exit area of the orifice aperture 209 to the external environment defines the drop weight of the ink droplet expelled. It has further been determined that the restoring force of the meniscus (constant K in the model) is determined in part by the proximity of the edges of the orifice aperture. Thus, to increase the stiffness of the meniscus, the sides and opening of the orifice bore hole should be made as close together as possible. This, of course, is in contradiction to the need to maintain a given drop weight for the droplet (which is determined by the exit area of the orifice). A greater restoring force on the meniscus provided by the non-circular geometry causes the tail of the ink droplet to be broken off sooner and closer to the orifice plate thereby resulting in a shorter ink droplet tail and significantly reduced spray.
Some non-circular orifices which may be utilized to reduce spray are elongated apertures having a major axis and a minor axis, in which the major axis is of a greater dimension than the minor axis and both axes are parallel to the outer surface of the orifice plate. Such elongate structures can be rectangles and parallelograms or ovals such as ellipses and parallel-sided "racetrack" structures. Using the ink contained in a model number HP51649A print cartridge (available from Hewlett-Packard Company) and orifice aperture areas equal to the area of the orifice aperture area used in the HP51649A cartridge, it was determined that ellipses having major axis to minor axis ratios of from 2 to 1 through 5 to 1 demonstrated the desired meniscus stiffening and short tail ink droplet ejection.
FIGS. 7A-7B are plan views of the orifice plate external surface illustrating the various types of orifice bore hole dimensions. FIG. 7A illustrates a circular orifice having a radius r at the outer dimension and a difference in radius between the outer demension r and the opening to the firing chamber of value r2. In the HP51649A cartridge, r=17.5 microns and r2=45 microns. This yields an aperture area at the orifice plate outer surface (r2�π) of 962 microns2. FIG. 7B illustrates an ellipsoidal external orifice aperture geometry in which the major axis/minor axis ratio equals 2 to 1 and, in order to maintain an equal droplet drop weight, the outer area of the orifice opening is maintained at 962 microns2. Thus, from the formula for the area of the ellipse (A−π�a�b), the major and minor axes (a, b) of the ellipse are respectively 28.5 microns and 12.4 microns for the 2:1 ellipse.
As suggested above, the major contributing factor to the better tail break-off and subsequent spray reduction is the reduction of the size of the minor axis of the ellipse. Within the range of axis ratios of 2:1 to approximately 5:1, reduction of spray is observed. One drawback, which was also noted above, is that elliptic orifi surface openings have a corresponding larger opening at the interior surface of the orifice plate (at the ink firing chamber). These interior openings will overlap and interfere when the orifi are spaced closely together for improved print resolution. This interference takes the form of ink from one firing chamber being blown into an adjacent firing chamber and other subtle but detrimental effects.
In order to resolve the interference problem, the ellipse has been distorted in the major axis direction, to create, in essence, a crescent or quarter moon shape. The minor axis dimension is preserved and the effective major axis is shortened with this crescent shape while the overall orifice aperture area remains constant. Appropriate spray reduction continues to be achieved using a crescent orifice opening shape. The crescent shape, however, introduces a different problem into the quality of print realized with this form of printhead. The trajectory of the ink droplets leaving the orifice plate is not perpendicular to the orifice plate surface but is tilted away from perpendicularity toward the direction of the negative radius of curvature surface of the orifice aperture.
To resolve the trajectory problem of the crescent orifice aperture shape, another shape which provides symmetry is created by overlaying two crescent shapes with the limbs of the crescent facing away from each other. Such a shape is illustrated in FIG. 8A. This modified orifice aperture shape has been deemed a "hourglass" shape. The modified minor axis (bH), in one implementation, has been set at 26 μm while the modified major axis (aH) has been established at 69 μm. The edges which define the modified minor axis for this implementation have a radius of curvature (rH) of approximately 47 μm. This orifice aperture shape preserves the narrow minor axis opening while reducing the necessary major axis dimension required for the fixed orifice aperture area. The reduced dimension major axis allows closer spacing of the orifi than could otherwise be realized with an ellipse of the same orifice aperture area. Further, the hourglass orifice aperture shape provides a symmetry about both major and minor axes and reduces the problem of trajectory error of an ink droplet. The improvement afforded by a non-circular orifice aperture over a conventional circular opening can be appreciated by comparing FIG. 9B with FIG. 9A. The highly magnified letters of FIG. 9B show very few of the extraneous droplets which are seen in the print of FIG. 9A.
Referring now to FIG. 8B, and to obtain an even greater trajectory error reduction, a reliable point of tail break-off is established in an hourglass shape having the orifice aperture asymmetrical with respect to the modified minor axis. The asymmetric hourglass orifice aperture is shown as orifice aperture 803 in FIG. 8B. The orifice aperture 803 hourglass shape comprises the edges of the orifice aperture at thee outer surface of the orifice plate. In a preferred embodiment, the peripheral shape of the orifice aperture is formed by two arc segments having a common center point of radius 805 and a common radius magnitude, re, but the first arc segment 807 being larger than the second arc segment 809 (disposed opposite the first arc segment). The orifice aperture 803 hourglass shape aperture periphery also comprises two arc segments 811 and 813 joining the adjacent end points of arc segments 807 and 809 to complete the periphery of the orifice aperture 803. The arc segment 813 has a radius magnitude, rH1, and a center point of radius 815 that is located outside of the hourglass periphery but disposed within a protrusion 817 in the orifice aperture formed at the other, inner, surface of the orifice plate adjacent the ink ejector. The arc segment 811 also has a radius magnitude rH2, and a center point of radius 819 within another protrusion 821 at the inner surface orifice aperture. It is a feature of the present invention that the center 815 is disposed nearly on the opposite side of the orifice from the center 819 but not exactly opposite. In a preferred embodiment, a line drawn joining the center 805 with the center 815 intersects a line drawn joining the center 805 with the center 819 and forms an acute angle θ. The acute angle θ formed between the two lines is adjusted to be in the range of 0� to 20� and preferably is approximately 5�. Thus, the orifice aperture 803 formed by electroplating at the outer orifice plate surface has an asymmetric hourglass orifice aperture and has an orifice aperture at the inner orifice plate surface comprised of two long arc segments having a common center and separated by the two protrusions. The ink drop tail preferentially breaks off from the narrower end (that is, at shorter arc segment 809) and provides a reliable location of tail break-off and spray. Uniform trajectory is achieved for drops ejected from each orifice employing the asymmetric hourglass shape.
As previously described, the orifice plate is conventionally formed by electroplating nickel or similar metal on a mandrel and then plating the orifice plate with chemically resistant materials such as gold. Previously, it has been known to utilize a non-conductive button in the shape of the desired end result: the circular orifice aperture. In order to create an hourglass-shaped orifice opening, however, it was determined that a button having a shape much less complicated than an hourglass shape could be used. Since during electroplating the orifice plate base metal grows uniformly in each available direction from a conducting surface (including its own surface) details in the non-conducting button shape would be obscured by the growing base metal. Likewise, a detail in the button shape can be transformed into an entirely different shape as the base metal grows. Consider, again, FIG. 1 in which the base metal 107 grows over the top surface of the non-conducting insulating button 105. When viewed in the plan view, a detail in the outline of the button 107 can be obscured or transformed into other shapes as the base metal 107 grows over the insulating button 105 top surface.
It has been found that an analysis technique utilizing a family of circles having a diameter equal to the desired base metal growth can be placed in the same plane and tangential to the outside outline of the desired orifice shape. When the point on the circumference of the circle opposite the point of tangency and sharing the same diameter line is joined to each other similar point of the family of circles, the shape the non-conducting button must take is revealed. An alternative procedure uses arcs of radii drawn from all or a representative number of points on the outside outline of the starting shape. The end point of the radius of each arc (perpendicular to a line drawn tangent to the point of the starting outline) defines a point on the orifice shape which results after the plating process is complete. Reference to FIG. 10 will aid in visualizing the technique using the family of circles.
In FIG. 10, the hourglass shape of the orifice aperture is identified as 1001. A family of circles having a radius equal to the desired growth of base metal is represented by circle 1003. The outline of the non-conductive button is shown as 1005. Each circle of the family of circles is made tangent to the hourglass orifice shape at a point along the edge of the hourglass shape. Taking the point directly across the diameter of each circle and joining those points yields the shape of the non-conducting button. When dealing with more complex orifice shapes, it has been found that the shape of the non-conducting button does not have to be identical to the shape of the orifice. Observe that at the limbs of the hourglass shape 1001, the number of circles needed to define the shape diminishes.
FIG. 11 illustrates the necessary construction circles needed to create the orifice opening 1001. Joining the points on the circumference opposite the point of tangency yields the minimum button outline needed to produce the hourglass orifice opening desired. These outline configurations include arc 1101 and arc 1103 to produce the edges forming the terminals of the major axis and parabolic portions 1105 and 1107 to produce the edges forming the terminals of the minor axes. As long as the remainder of the button outline does not come closer to the desired orifice shape than a circle diameter, the hourglass orifice shape produced by electroplating an orifice plate will be independent of the button outline other than the identified arcs and parabolic sections.
This outline independence is used in an embodiment of the invention to provide improved adhesion of the orifice plate to the barrier material and allows the firing chamber to be designed with a larger volume of ink. FIG. 12 illustrates the printhead which is obtained when the non-conducting mandrel button shape is partially independent of the orifice surface hole shape. The orifice aperture 1001 and the button shape 1201 are shown in solid line for the sake of clarity although the orifice hole 1101 is located on the external surface of the orifice plate and the button shape is located on the inner surface of the orifice plate. The bore of the orifice changes from the button shape 1201 to the hourglass shaped aperture 1001 as one views the orifice bore starting at the ink firing chamber and traverses to the opening at the surface of the orifice plate. In this embodiment, the configuration of the barrier layer material is shown in broken line. An island of barrier material 1203 divides the ink inlet to the firing chamber 1205 into two ink channels 1207 and 1209 and the remainder of the firing chamber 1205 is defined by walls of barrier material 1211, 1213, 1215, etc. Improved areas of contact between the barrier layer material and the orifice plate are realized in the zone around the barrier island 1203 (and illustrated with further broken line representing the hypothetical circular button outline). This improved contact area is a result of the squaring of the button shape in portions which would otherwise be circular to better match the square implementation of the barrier material and provides a rectangular cross section at the substrate which does not vary even when a misalignment of the orifice plate occurs. Further, the square implementation provides increased ink volume in the firing chamber.
Thus, the present invention utilizes an orifice aperture shape that is an asymmetric hourglass shape that produces ejected ink drops having reduced spray and improved ink drop trajectory.
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Hi everyone! I'm sorry I disappeared. We are in week 3 of our relocation to the hotel, and we'll be here until at least Dec 6th. The wifi is really, really bad ... practically unusable.
We do have insurance covering the relocation but it's been stressful ... they didn't know until the last minute if they were going to cover, then they said they would but we couldn't find a hotel that would bill them, they all wanted to bill my credit card (sadly I don't have 6K on my credit card to pay for it) ... then with help we found a hotel that would bill insurance so we moved here ... but then after a week they billed my credit card anyway! We sorted that and they refunded my card and said they would bill insurance. Then the strata was going to do some plumbing and insurance said they wouldn't cover the days the plumber was there, and then strata decided NOT to do plumbing and insurance called the hotel to sort everything out and the hotel said 'no, we're planning to bill everything to the credit card.'
So we've been living here, not knowing if we're going to have to find a way to pay for some or all of it and wait for reimbursement, spending more on gas (the hotel is 10 minutes away from home so 10 minutes further from everything we do), spending more on food (there is a kitchen but it's tiny, and we don't have our pantry of spices and sauces to cook from), and trying to hold it together.
There is a pool, so that's a plus
And hey, having housekeeping coming regularly is nice, too. But the thrill of those things wore off after day 2 LOL.
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A surgical scalpel blade made safer by providing, on the front portion thereof, a blunted surface or tip which renders the point of the blade incapable of cutting, without impeding the ability of the blade to be drawn across the surface to be incised.
1. A surgical scalpel blade defined by a sharpened first edge adapted to cut by drawing along a surface to be incised, a second edge opposite said first edge, a proximal end portion at a proximal end of said first edge and a proximal end of said second edge being adapted to accept a scalpel handle, and a distal end portion at which a distal end of said first edge and a distal end of said second edge meet at a juncture,
a tip portion having a cross section greater than that of said blade being provided at said juncture, the greater cross section of said tip portion rendering said distal end of said first end incapable of cutting,
said first edge of said blade having a belly portion extending further from said second edge than said tip portion, whereby the drawing of said blade is substantially unimpaired by said tip portion, said second edge being straight, said first edge curving from said belly portion toward said first edge at said distal end portion.
2. The blade of claim 1 wherein said tip portion is a sphere.
3. The blade of claim 1 wherein said tip portion is a cone.
4. The blade of claim 1 wherein said tip portion is a teardrop.
5. The blade of claim 1 wherein said tip portion is a half sphere with an exposed surface facing said proximal end portion.
6. The blade of claim 1 wherein said second edge curves toward said first edge, and said first edge curves toward said second edge at said distal end portion.
7. The blade of claim 1 wherein said second edge surface has an increased thickness.
8. The blade of claim 1 wherein said second edge surface is wavy.
this application is a continuation of application Ser. No. 08/055,209, filed Apr. 29, 1993, now abandoned.
The present invention is directed to a new surgical scalpel blade and, more specifically, to such a blade designed to protect medical personnel from injuries caused by the inadvertent penetration of the skin by the scalpel blade tip and cutting surface.
A typical surgical scalpel blade is designed to be detachably attached to a surgical scalpel handle and comprises a cutting edge which culminates in a point. This point is extremely dangerous due to the sharpness thereof and oftentimes, during, for example, a transfer between the surgeon and the nurse, the tip is inadvertently caused to penetrate the flesh of either. Similarly, hasty reactions by the surgeon and the assistants after inadvertent vessel wall injury and subsequent bleeding can cause scalpel injury. In this instance, quick reaction time by the surgical team to control hemorrhaging is associated with scalpel lacerations. It is assumed by the lay person that such accidents are unavoidable as the sharp tip of the scalpel blade is essential to the cutting for which the scalpel is designed. This assumption, however, is erroneous.
Scalpel blades are designed to cut due to a backward drawing motion of the sharp edge of the scalpel against the surface to be cut. The curved belly of the scalpel blade makes its cutting motion unique. The preferred method of incising the skin is with the belly of the blade, although, some surgeons prefer to use, exclusively, the point of the blade. Thereafter, the belly of the blade does nearly all the sharp dissection of the underlying soft-tissue. Scalpels, which are controlled by finger motion, are not used in conjunction with stabbing or hacking motions as is the case with hand-held knives. Thus, the tip of the scalpel can be modified to prevent the point from inadvertently stabbing hospital personnel without compromising its cutting ability. At the same time, however, the modification must be one that does not prevent the drawing of the blade necessary to make an incision by creating substantial drag or resistance. Although innovations have been made in surgical scalpels to decrease handling of the sharp blades during the changing thereof, Applicant surprisingly found that no attempts to increase the safety of the scalpel during its use were previously made by improving the design of surgical scalpel blade tips, by modifying the shape of the cutting surface belly, by shielding the tip, or by changing the angle thereof. Nor had anyone previously created a top finger or clamp gripping surface on the blade.
In view of the foregoing, it is an object of the present invention to provide a scalpel blade which will protect against inadvertent puncture wounds and, at the same time, will not impair the ability of the blade to be drawn across the surface which is to be cut.
It is a further object of the invention to provide a scalpel blade which will deflect previously cut surfaces away from the belly of the blade and which can be further used to make cuts of a controlled depth by effectively shielding deeper tissues from the cutting edge.
It is a further object of the invention to supply a scalpel blade that can act as a retractor while effectively protecting adjacent tissue.
It is yet a further object of the invention to provide a scalpel blade that has a top surface that allows for finger or clamp gripping to give a secure hold during blade changes.
Other objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings.
FIGS. 1a to 1h illustrate side views of various embodiments of the invention incorporating different shaped tip shields and various blade designs;
FIG. 1i shows an oblique side view of an inventive blade with a modified second edge surface.
FIG. 2 shows the manner in which the inventive scalpel is used in conjunction with deflection cutting;
FIG. 3 demonstrates the use of the inventive scalpel blade in a protective cutting procedure;
FIG. 4 shows the use of the inventive blade in retraction.
An inventive surgical scalpel blade is illustrated in FIG. 1a. The inventive blade is defined by a first edge surface 1 adapted to cut when drawn across the tissue in which an incision is to be made. Opposite first edge surface 1 is second edge surface 2; the proximal ends of the first and second surfaces end at a proximal end portion 3 adjacent to the scalpel handle.
Distal ends of first edge surface 1 and second edge surface 2 meet at distal end portion 4 of the blade, which is remote from end portion 3. Distal end portion 4 has edge surface 5 modified to be incapable of cutting. At the same time, this modification of edge surface 5 of distal end portion 4 cannot impede the drawing of the blade across the surface being cut.
To render edge surface 5 of distal end portion 4 incapable of cutting, distal end portion 4 can be blunted; however, it is preferable that, at the same time edge surface 5 is formed with an increased thickness. Preferably, the thickness of edge surface 5 is increased by positioning smooth non-penetrating contoured tip 6 on distal end portion 4 of the blade. By forming tip 6 with a smooth, rounded contour, the tip can be made to deflect the previously cut surface away from the belly of the blade. Tip 6 can be spherical as shown in FIG. 1a, and can be varied in size as illustrated by FIG. 1b. The shape of tip 6 is not limited to that of the sphere, but can also be formed in the shape of a teardrop (FIG. 1c), a modified teardrop (cone-shaped as shown in FIG. 1d), or a halved sphere (FIG. 1e). The only limitation on the shape of tip 6 is that it does not impede the drawing of the blade across the surface being cut. The inventive blade can have the traditional design for handle attachment or can have attachment portion 7 adapted to permit attachment of the scalpel blade to a scalpel handle (not shown). It is also possible to form the blade integrally with a handle.
Second edge surface 2 can curve downward at distal end portion 4 so that tip 6 is provided below the plane of second edge surface 2 (see FIG. 1f). By so forming the blade, the probability of a head-on approach is reduced further preventing operating room personnel from receiving inadvertent cuts. In addition, second edge surface 2 can be provided with widened portion 12 to form a surface on which the user's finger can at least partially rest, to better guide the blade (see FIG. 1g). The belly of the blade can have either the traditional shape, or a diminished curvature (see FIG. 1h), which will expose less cutting surface and decrease the chance of a penetrating injury. A smooth wave formed on second edge surface 2 can also be provided to form a secure finger or clamp hold useful during blade changes. Second edge surface 2 can, thus, be straight, or alternatively, wavy (see FIG. 1i).
FIG. 2 illustrates the use of the inventive blade in normal deflection cutting and, as is clear therefrom, tip 6 can effectively deflect previously cut tissue 9 away from the belly of blade 10 during cutting so the depth of the cut can be more accurately gauged. In protective cutting, as shown in FIG. 3, the scalpel can be used upside down and effectively shields deeper tissues 11, such as blood vessels, nerves, and tendons from the cutting surface. With a conventional blade such cuts are extremely hazardous as the deeper tissue is easily nicked by the exposed point of the conventional scalpel. FIG. 4 illustrates the use of the inventive blade as a retractor, again effectively protecting adjacent tissue during retraction.
Thus, because of tip 6, the inventive blade has a number of advantages over those heretofore used. It can prevent inadvertent puncture injuries to operating room personnel and, at the same time, allow the user to more accurately make incisions, while shielding surrounding tissue from the cutting edge of the blade. The ability of the blade to be drawn along the surface to be cut is not impaired. The inventive blade can be used in either deflection or protective cutting procedures, and can also be employed as a retractor.
While only the fundamental novel features of the invention as applied to a preferred embodiment thereof have been shown and described, it is understood that various omissions, substitutions, and changes in the form and details of the device illustrated and in its operation may be made by those skilled in the art without departing from the spirit of the invention. It is therefore the intention of Applicant that the invention be limited only as indicated by the scope of the claims appended hereto.
Patent Citations
Referenced by
Legal Events
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We always knew that Kourtney Kardashian is super hot, but we never really realized how much of a badass she is until this past year. Why, you ask? The fact that she birthed her second child Penelope by pulling it out of the womb herself. Pretty badass.
Oh hey, speaking of asses (zing!) the eldest Kardashian sister stared in a new reality spin-off with her sister Kim called Kourtney and Kim Take Miami (not to be confused with Kourtney and Khloe Take Miami, or Kourtney and Kim Take New York). The series featured plenty of new bikinis, and Kim's adorable kitten named Mercy (RIP *tear*). But on the other hand it did feature Scott Disick dude, but hey, nothing's perfect!
Between all of the babies, television, tabloid drama and family beefing, it's been a busy year for Kourtney…but then again we'd expect nothing less from the Kardashians. In honor of the super sexy mama's 34th birthday today, we've assembled her 34 sexiest photos of all time. Head up to the gallery above and enjoy!
[Photo: Splash News Online/Shape Magazine]


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Winedale - Christmas at Winedale
Join us for "Christmas at Winedale," Saturday, December 14, 2013, from noon to 4 p.m. Take a ride on the Old West stagecoach as you view the way the countryside might have looked in the mid-1800s with historic homes, a one-room schoolhouse and folk life demonstrations. Admission is free and open to the public.
Tour decorated historic homes and enjoy demonstrations of blacksmithing, quilting, weaving, spinning, rope-making, basket-weaving, wood-working, pottery, lace making, pioneer encampment and much more. Children's activities include old-fashioned crafts, games, hands-on chores and kid-friendly farm animals. You might even see our Weihnachtsmann (German Santa Claus)!
Featured entertainment will include The German Singers, Star of Texas Dulcimers, Celtaire String Band, Shakespeare players, story tellers, folk musicians, folk dancers and more. Food and drinks will be available for sale.
Winedale Historical Complex, is located four miles northeast of Round Top, Texas, at 3738 FM 2714 (off FM 1457). Directions and Maps.
For more information call (979) 278-3530 or email: email@example.com.
December 2012
"Christmas at Winedale" was once again a great sucess. Taking place on Saturday, December 8, the folklife event drew people from across the state. Visitors were able to tour historic structures, staffed by volunteers in period costumes. Volunteers cheerfully shared historical knowledge with guests about a wide range of 19th-century practices including metal working, wine making, quilting, weaving and pottery. Good weather enabled many outdoor activities including hay rides, a petting zoo, crafts and folk dancing.
Visitors also enjoyed a theatrical performance from Shakespeare's play A Midsummer Night's Dream (Act 5). Watchers experienced the performance in a converted 19th-century barn while eating traditional Hunter's Stew and gingerbread. Finally, musicians were dotted around the complex playing traditional music. Performers included the The German Singers, Star of Texas Dulcimers, and The Celtaire String Band. Click on the play button below to view The Celtaire String Band in action!
Christmas at Winedale takes place at the Winedale Historical Complex near Round Top, Texas. Winedale is a division of the Briscoe Center for American History, a historical research unit at the University of Texas at Austin.


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The Christ Child, at the Virgin's breast, stares out of the picture. The landscape with its tall mountains is typical of landscape depiction in the Low Countries in the 16th century.In the past this picture has been ascribed to van Orley, but it appears n
Find more like this:16th, 402000, appear, ascribed, been, breast, centur, child, christ, countr, depiction, it, landscape, low, mountain.
Product Information
|Product Code
|Style of Bernaert van Orley
The Virgin and Child in a Landscape
More information about framed prints
20% Cancellation Fee on Made to Order products
If you decided to cancel your made-to-order print for any reason, it is unlikely that we could sell it to another customer at full selling price. We'll therefore charge a cancellation fee of 20% of the order price.


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Samsung unveils Galaxy Music Duos smartphone
International Marketing Services, the authorized national distributor of Samsung mobiles in Nepal, has launched another Samsung phone with enhanced audio features, the Samsung Galaxy Music Duos smartphone. The new handset has a price tag of Rs 16,690.
The Samsung Galaxy Music Duos has a two SIM "Always On" feature and connectivity is always possible and keeps the user reachable. This smartphone has excellent sound quality largely due to its dual SRS speakers and "Sound Alive" feature. It connects to the net via WiFi or 3G and operates on an Android 4.0 Ice-cream sandwich platform (upgradable to Jellybean). It comes with an internal 4 GB memory that can be expanded up to 32 GB.
With other features like WiFi Direct, Bluetooth 3.0, GPS/Glonass connectivity and in-built antenna, the smartphone offers the best value-for-money in its segment, said the company.
Available at Samsung Stores and Outlets, the Samsung Galaxy Music
Duos is also displayed at
the Samsung Mobile Premium Brand Shop at Sherpa Mall, Durbar Marg.
Posted on: 2012-12-27 09:15


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Let's face it, animals are bastards. With all of the ant slavery, ape war and duck rape in the world, it's easy to decide nature is something best left to the wild. But there are those animals that -- thanks to Disney and The Far Side -- we tend to think are more likely to dispense witty one liners than bite our face. But while we've been busy rooting for them, they've been quietly revealing their true colors ...
(app103 posted it on FB)


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Mid-Coast recap: June brings playoff excitement
As this issue hits the streets, the baseball, softball and lacrosse regular seasons are coming to a close and the tennis and track postseasons have begun.
Here's a look at where things stand:
Tennis: Hill wins another singles crown
Mt. Ararat senior Mike Hill, the top seed, won his third straight boys' singles tennis championship Monday at Bates College in Lewiston, downing Waynflete's Brandon Thompson, 6-3, 6-3.
The team playoffs are underway.
The Mt. Ararat boys (10-2) earned the No. 4 seed in Eastern A and hosted No. 5 Mt. Blue in the quarterfinals Thursday (too late for print). Brunswick (7-5 and sixth) was at No. 3 Brewer. Morse (0-12) failed to qualify this spring.
On the girls' side, Brunswick (9-3) is the No. 5 seed and visited No. 4 Hampden Academy (9-3) on Thursday (too late for print). No. 6 Morse (8-4) was at No. 3 Cony (8-4). No. 7 Mt. Ararat (7-5) visited No. 2 Bangor (11-1).
The semifinals are Saturday on the court of the higher remaining seeds.
Track: Slotnick steals show at KVACs
Last Saturday was the beginning of the outdoor track postseason. Local runners, jumpers and throwers took part in the Kennebec Valley Conference championships in Bath. Edward Little won both the boys' and girls' meets. The Brunswick girls were second and the boys came in third. The Mt. Ararat girls were third and the boys were eighth. Both Morse teams placed sixth.
Individually, Dragons senior standout Kristin Slotnick again stole the show, wining the 100 (12.71 seconds), 200 (26.51), 400 (59.92) and leading the 4x400 relay team to a first place finish (4 minutes, 12.66 seconds, good for a new conference record). Kathleen McMahon won the two-mile (12:05.45). Kyia Jensen was first in the 800 (2:25.47).
Mt. Ararat had two girls' winners: Randi London (shot put, 34 feet, 2.5 inches) and Rebecca Merritt (300 hurdles, 47.95).
On the boys' side, winners included Brunswick's Kenzell Crawford (110 hurdles, 16.23) and Morse's Alonzo James (400, 51.21).
The three teams will next take part in the Class A state meet Saturday in Saco.
The baseball regular season has come to a close.
Brunswick won 6-4 at Lewiston Monday to finish 11-5. The Dragons were sixth in the latest Eastern Class A Heals and will await their final ranking. Mt. Ararat was 8-6 entering the week (good for seventh). Morse was 0-14 at the start of the week and won't qualify for the playoffs.
Softball has also come to an end.
Mt. Ararat (7-7 at the start of the week) is playoff bound. The Eagles were eighth in the latest Eastern A Heals. Brunswick went 7-9 and hopes to qualify. Morse was 2-12 at the beginning of the week and likely will be on the outside looking in.
Boys' lacrosse
The Brunswick boys' lacrosse team capped a 12-0 regular season Tuesday with a 17-0 win at Oxford Hills. The Dragons will be the top seed in Eastern Class A and will earn a bye into the semifinals. Mt. Ararat was 8-3 entering its finale at Messalonskee. The Eagles were third in the Heals. Morse wound up 9-3 after having a five-game winning streak ended, 11-10, at Mt. Blue Tuesday. The Shipbuilders are hoping to host a quarterfinal round Eastern Class B playoff game.
Girls' lacrosse
On the girls' side, Brunswick's quest for a second straight Class A state championship is looking good. The Dragons improved to 11-0 Monday with a 16-7 win at Mt. Ararat. Brunswick (which finished at Lewiston Wednesday, too late for print) will be first when the playoffs start. The Eagles (9-3) will likely be third. In Eastern B, Morse wound up 6-6 after Monday's 13-8 loss to Messalonskee. The Shipbuilders were third in Eastern B and will probably meet defending regional champion North Yarmouth Academy in the semifinals, a week from Saturday. Morse first hosts its alumni game Friday.


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- Willamette
- The Scene - Archives
- Editions
- 2012
- Spring 2012 Edition
- Departments
- President's Message
President's Message
Willamette's revised mission statement, approved in February by the Board of Trustees, charges the institution, through our rigorous education in the liberal arts and professions, to prepare our graduates to "transform knowledge into action and lead lives of achievement, contribution and meaning."
And they do.
For 170 years, Willamette has been a place where many generations of promising young people have discovered their passions and found their paths. Whether they become Peace Corps volunteers, Olympic athletes, teachers, United States senators, Nobel Prize laureates, artists, authors, entrepreneurs — or undertake any of a myriad of diverse and worthy pursuits — Willamette alumni are continually changing our world for the better. They are recognized as individuals of excellent character and achievement in their careers, engagement in civic activities, volunteerism in the community and genuine passion for what they do.
Connecting our students' own passions and interests with the benefits of a liberal education — awakening them to the power of their own potential and empowering them to apply knowledge in ways that create meaning — is the deepest purpose of a Willamette education. I can think of no endeavor more worthy of our time and attention than supporting an institution that has helped launch so many good and useful lives.
This issue of The Scene includes a story about how a recent history project connected current students with Native American alumni, broadening the experiences and perspectives of both, as well as a feature about a new archaeological dig in Orkney where faculty and students will spend the summer unearthing a "Neolithic cathedral."
Stephen E. Thorsett
"The young do not know enough to be prudent, and therefore they attempt the impossible — and achieve it, generation after generation."
— Pearl S. Buck


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I am a civic media scholar and strategist, from games to mobile media for learning and civic engagement. In 2004 I co-founded Games for Change, and today continue to build the field of social issue games. Previously, I was a program officer at the MacArthur Foundation in their portfolio on Digital Media and Learning. I am currently a postdoc scholar the UC Berkeley School of Information, after finishing my PhD in 2014 at USC Annenberg. You can follow me on Twitter @bgstokes and on LinkedIn.
Research Expertise:
- Civic learning through real-world games: I study how digital media can structure participation in real-time, engaging participants as they build civic skills in the physical world, and form network ties with immediate impact on neighborhood social issues.
- Participatory design as civic engagement: I also facilitate and teach community-based design, blurring the overlap of digital and physical worlds (from reinventing the bus stop to mobile mapping), empowering participants to tell a collective story about the future of their neighborhood, while learning skills of coding and urban planning.
Research Group Affiliations (see also my Projects): I have been investigating how mobile media can situate civic learning in the physical world with the Situated Engagement Group that I helped start with François Bar at the USC; in my work with Tracy Fullerton at the Game Innovation Lab I study how real-world games shape learning networks; in working with the Metamorphosis project led by Sandra Ball-Rokeach I study neighborhood empowerment by analyzing the local communication ecology; and across all this, in my work with Henry Jenkins in Civic Paths I investigate how civic life is changing for young people in a digital age as part of the MacArthur Research Network on Youth and Participatory Politics. I am currently a research fellow at the Center for Media and Social Impact at American University, where I am working with Games for Change to develop a typology of impact for games addressing civic issues.
Additional Background: I have managed programs at NetAid/Mercy Corps in gaming, online volunteering, and online peer learning for global citizenship (now the Global Citizen Corps). Working in educational technology, I was a producer at ProQuest/Bigchalk.com, which reached more than 43,000 schools. I have developed digital games (see the Peter Packet Challenge) and learning communities that engaged more than 150,000 youth in fighting extreme poverty. I studied the single atom wire for my B.A. in physics at Haverford College, and studied West African drumming in Senegal.
Contact me: If you need to reach me by email, please write firstname.lastname@example.com.
* Photo credit: Ida Benedetto