US 3452360 A
Description (OCR text may contain errors)
I Julie 24, 1969 w s0 3,452,360
HIGH-SPEED STYLOGRAPHIC APPARATUS AND SYSTEM FiledJuly. 28. 1967 Sheet of 2 l l T is [ll/l1 f IN VEN TOR.
ROBERT R. WILLIAMSON BY (7 ATTORNEY June 24, 1969 R. R. WILLIAMSON 3,
I HIGHSPEED STYLOGRAPHIC APPARATUS AND SYSTEM Filed July 28, 1967 Sheet 2 of 2 MODULATOR I- COMPUTER 4'---|NPUT AMPLI Fl ER OSCILLATOR FIG.6
ROBERT R. WILLIAMSON ATTORNEY United States Patent O 3,452,360 HIGH-SPEED STYLOGRAPHIC APPARATUS AND SYSTEM Robert R. Williamson, Glendale, Calif., assignor to General Precision Systems Inc., a corporation of Delaware Filed July 28, 1967, Ser. No. 656,817 Int. Cl. G01d 15/18 U.S. Cl. 346140 7 Claims I ABSTRACT OF THE DISCLOSURE An ink-ejecting stylograph and a system for its use in high-speed printing and writing. A pen barrel, Supplied with ink fluid and having a flexible nozzle at one end, is provided with a magnetostrictive rod immersed in the ink and extending inside the barrel to the region of the nozzle. The magnetostrictive rod is excited by a highfrequency driving signal, modified in accordance with an information signal which causes the rod to flex said nozzle and to eject minute droplets of ink, in quantity, size and timing in accordance with the information signal. The ejected ink droplets are received upon a web of paper or other recording surface moving at a known speed, in close proximity to the nozzle.
BACKGROUND OF THE INVENTION This invention relates to the art of printing or writing. More particularly, it relates to an ink-ejecting stylograph or pen for writing or printing upon a receiving surface in response to information signals, and to a system for its employment.
High-speed printers are known in which ink under pressure is ejected in the form of droplets, from a rapidly vibrating nozzle. The droplets are electrically charged and pass through a deflecting field created between charged plates, the field being varied in accordance with an information signal in order to deposit the droplets at desired locations upon a moving web of paper, and thus to form intelligible writing or printing. Such an arrangement is shown in the patent to R. A. Adams et al., No. 3,281,860, issued Oct. 25, 1966. In such prior art systems, the droplets are of uniform size and, in passing through the deflecting field, travel a considerable distance to the writing medium. During a comparatively long transit time, they must be charged as they leave the nozzle, must form into droplets of uniform size, and must then be deflected to an exact point of impact on the moving web of paper, providing many possibilities for error, in a process which should be substantially error free, and, moreover, slowing the process.
SUMMARY Difliculties with ink-ejecting printers in the prior art have been obviated by the high-speed stylographic system and apparatus of the applicant. According to the invention, a magnetostrictive rod, immersed in an inkcontaining barrel having a flexible nozzle, expands and contracts in accordance with high-frequency electromagnetic excitation, flexing said nozzle and ejecting minute droplets from a nozzle operating in close proximity to a moving web of paper or other writing medium. The excitation signal supplied to the stylograph is modulated in accordance with information supplied from a computer system, so that the droplets of ink ejected from the stylograph nozzle at any instant are of a size and number to imprint a desired incremental portion of an alphanumeric character, half-tone reproduction, or whatever.
It is therefore an object of the invention to provide a "ice high-speed stylograph or ink ejector which will operate in close proximity to a rapidly moving Web of writing medium. It is a further object of the invention to provide a high-speed stylograph in which minute ink droplets ejected from the nozzle can be varied in size and number as desired at a given instant. It is yet another object of the invention to provide a high-speed stylographic system in which multiple stylographs can be arranged in battery and linked with a computer, so that even a very wide web of paper or other writing medium, such as newsprint, moving at high speed, can be adequately covered, and the detail rendered will be sufficiently fine for use in a half-tone reproduction process, for example.
These and other objects of the invention will be apparent from the ensuing description and from the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS FIGURE 1 is an elevational view of a stylograph according to the invention;
FIGURE 2 is a longitudinal cross section of the stylograph of FIGURE 1, taken along the line 2-2, but showing the magnetostriction rod in elevation;
FIGURE 3 is an enlarged cross section taken along the line 33 of FIGURE 2;
FIGURE 4 is an enlarged cross-sectional view of the nozzle, taken along the line 4-4 of FIGURE 2;
FIGURE 5 shows schematically the manner in which multiple stylographs may be employed to provide coverage across the width of a moving web of writing medium; and
FIGURE 6 is a block diagram of the circuitry employed in a stylographic system according to the invention.
DESCRIPTION OF A PREFERRED EMBODIMENT Referring to FIGURES l-4 of the drawings, there is shown a stylograph 10, having a generally cylindrical, tubular barrel 12, providing at one end with a nozzle 14 which blends from a generally circular cross section where it joins the barrel 12 to a generally elliptical cross section (FIGURE 4), near its midpoint and to its terminus, where it is provided with a very small, preferably elliptical, delivery orifice 16. The barrel 12 is supplied with fluid ink through a supply connection 18, connected by a conduit 20 to a source of ink (not shown). The barrel, nozzle, and supply connection may be of unitary construction, molded in one piece from a suitable structural plastic such as a polyamide or acetal resin. The wall of the nozzle 14 is made thinner, and therefore more flexible, than the wall of the barrel 12, for a reason presently to be explained.
The end 22 of barrel 12, opposite the nozzle 14, is closed by means of a sealing plug or sleeve 24, preferably made of an elastomeric damping material such as one of the silicone rubber sealant compounds supplied by General Electric, Dow-Corning, and other manufacturers.
A magnetostriction rod or plunger 26 extends into the barrel 12 and has its forward end 28 terminated adjacent the nozzle 14, its after end 30 projecting from the end 22 of the barrel 12 and being sealed by the plug 24. An electrical excitation coil 32 is wound upon a plastic insulating sleeve 34, fitted upon the after end 30 of the rod 26. Electrical leads 36 extend from the excitation coil 32 and are connected to the source of a driving signal.
A typical stylograph according to the invention has a magnetostriction rod or plunger of about 0.01 inch in diameter and from 3 to 6 inches in length, with a barrel length of about 2 to 4 inches, a barrel external diameter of, typically, about 0.20 inch, and a barrel wall 0.010 inch thick. The major diameter of the elliptical orifice 3 16 is of the order of 0.013 inch, or about the size of a No. 80 drill. The -wall of the nozzle 14 tapers in thickness from 0.010 inch where it joins the barrel 12, to about 0.003 inch at the delivery orifice 16.
The excitation coil 32 of the stylograph, typically, is made with about to 20 turns of No. 30, Formvar insulated, copper magnet wire, Wound upon a sleeve 34 of suitable plastic tubing, snuggly fitted to the after end 30 of the magnetostriction rod 26. The sleeve is, however, slidable upon the rod, so that the coil can be shifted'in position in the process of adjusting and tuning the stylograph for maximum efiectiveness.
As mentioned previously, the stylograph of the invention is intended to be operated in close proximity to the Writing medium. A typical operating distance, from the end of the nozzle 14 at the delivery orifice 16, to the web 40, is 0.001 to 0.005 inch. The nozzle need only be placed far enough from the web so that the minute droplets issuing can form as discrete entities without smearmg.
In the operation of the stylograph according to the invention, a driving signal, AM, or otherwise modulated in accordance with an output from a computer or other source, as indicated in FIGURE 6, is impressed, at preferably 500 to 2000 kilohertz carrier frequency, upon the excitation winding 32. In response to this excitation, the magnetostriction rod 26 expands and contracts at this frequency, and with each expansion, displaces a minute amount of ink. In the build up of pressure occasioned by each minute expansion of the magnetostriction rod 26, there is a build up in fluid pressure within the stylograph barrel 12, entailing a minute flexing of the wall of the nozzle 14, which, as previously mentioned, is generally elliptical and thinner than the main portion of the barrel.
When the fluid pressure in the barrel builds up with each expansion stroke of the rod 26, the elliptical wall of the nozzle 14 and orifice 16 flexes and tends to assume a more circular shape and a larger periphery, otfering less resistance to flow through it. Upon the ensuing full contraction of the rod 26 and its consequently decreased displacement, the fluid pressure drops to a slightly negative value, i.e., a lesser value than when the rod is at its neutral dimension, and the wall of the nozzle and orifice tends to return beyond its normal elliptical shape, to a smaller-thanf-normal periphery, having a slightly increased resistance to flow. This slightly increased flow resistance of the nozzle, upon contraction of the rod, slightly impedes back flow of ink. The aggregate result is a slight check valve or diode action, resulting in the ejection of a minute droplet of ink from the orifice 16, because of fluid displacement by the rod 26.
An additional factor contributing to the diode or check valve effect arises out of the irreversibility of droplet formation under surface tension. Once having been ejected and formed, or nearly so, a droplet will tend not to coalesce back into the cohesive body of fluid from which it came.
Referring to FIGURE 5, a battery 38 of the stylographs 10, is shown disposed across the width of and in close proximity to a web 40, of paper or other writing medium moving in the direction indicated by the arrow. For purposes of illustration, a single row of stylographs is shown, placed as closely together as their barrel diameters will permit. However, for printing of the fineness of a typical newspaper half-tone screen, for example, multiple rows of stylographs stepped echelon are employed, each row slightly offset from the preceding row, so that the paths traced by the stylographs on the moving web 40 are spaced apart a distance equal to the center-to-center distance of two adjoining half-tone dots.
In FIGURE 6, a block diagram is shown of the circuitry employed in the operation of a multiple stylograph system according to the invention. The excitation coil 32 about the magnetostriction rod 26 is connected to an amplifier 42, which supplies the driving signal to the coil in order to excite the rod. The amplifier is supplied with power from an oscillator 44 at a carrier frequency preferably in the range of from 500 to 2000 kilohertz, for example. The carrier signal is modulated by an output from a modulator 46, in accordance with a command signal received from a computer 48. Into the computer are supplied the necessary information signals representative of the speed of the web 40 and the size and location of the droplets of ink to be ejected by a particular stylograph at a specific instant, in order to print, by incremental build up, the desired graphic output on the web 40.
The source of information to the computer 48 may be, for example, any suitable known mechanism for scanning graphic or other displays, photographic negatives, positives or transparencies, in order to supply a reprcsentative input to the computer and instruct the system to print the desired reproduction. Many other uses of the invention will suggest themselves to those skilled in the art.
It will be understood by those skilled in the art that the embodiments, dimensions, materials, and other design criteria given herein are merely exemplary, and are not to be regarded as limitative of the breadth and scope of the invention.
1. stylograph for high-speed writing and printing, comprising:
an ink container having flexible ink delivery nozzle connected thereto; an ink delivery orifice at the terminus of said nozzle; a magnetostriction rod disposed for immersion in the contents of said container, one end of said rod terminating in proximity to said nozzle, said nozzle being responsive to the operation of said rod; and
means for magnetically exciting said rod so that the stroke of said rod flexes said nozzle to eject droplets of ink therefrom.
2. stylograph for high-speed writing and printing, comprrsmg:
an ink barrel of generally tubular form, one end of said barrel being open and the other end having a pointed nozzle, the walls of said barrel and nozzle being constructed of a resilient material, the wall of the nozzle being generally thinner than the wall of the barrel;
an ink delivery orifice at the terminus of said nozzle;
a magnetostriction rod within said barrel, one end of said rod terminating in proximity to said nozzle, said nozzle being responsive to the operation of said rod, and the other end projecting from the open end of said barrel;
means for magnetically exciting said rod so that the stroke of said rod minutely flexes said nozzle to eject droplets of ink therefrom; and
fluid-tight means for sealing the entry of said rod into the end of said barrel.
3. A stylograph according to claim 2, in which the wall of the nozzle is thinner toward its delivery end than at its end adjoining the barrel.
4. A stylograph according to claim 2, in which the nozzle blends in cross section from the shape of the barrel where joined thereto, to a generally elliptical cross section toward the delivery orifice.
5. A stylograph according to claim 2, in which the magnetostriction rod is encircled by an electrical excitation coil.
6. A stylograph according to claim 2, in which the sealing means is constructed of a vibration absorbing material.
7. In a high-speed stylographic printing system, the combination of: Y
a battery of electromagnetically excited, magnetostriction actuated stylographs, each disposed upon receipt of an excitation signal, to deliver ink upon a web of References Cited writing material moving at a known speed, each also having a flexible nozzle responsive to expand and UNITED STATES PATENTS contract when said stylographs are electromag- 2 512,743 6/1950 Han en.
3:??? g ff Odul ted e .tatio ignal to 5 2,951,894 9/1960 Hirsch 346-440 X mm o ppyigam a XCl ns each of Said stylographs; 3,334,354 8/1967 Mutschler 346-140 means modulatmg Said. F Q slgnal accord RICHARD B. WILKINSON, Primary Examiner.
ance with a command signal Indicative of the speed of said web and a desired graphic print-out; and JOSEPH W. HARTARY, Assistant Examiner. means for supplying said command signal to said modulating means.