US 2766717 A
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Description (OCR text may contain errors)
Oct. 16, 1956 s. NElDlCH ETAL 2,756,717
APPARATUS FOR IMPREGNATING INKTRANSFER RIBBONS Filed March 17, 1953 INVENTOR.
GEORGE G. NElD/OM EM R) M. LOW BY ANDHENRYAMART/MJR THEIR ATTORNEY United States APPARATUS FOR HIVIPREGNATING INK-TRANSFER RIBBONS Application March 17, 1953, Serial No. 342,876
2 Claims. (Cl. 11833) This invention relates to means for impregnating inktransfer ribbons, such as employed in typewriters and similar printing machines. Ink-impregnated ribbons of this nature have been customarily impregnated throughout with varying amounts of ink, as desired, as distinguished from ribbons or other webs having a surface coating of an adhesive, or protective, or like character. Such impregnation has been commonly effected by the application of an excess quantity of the ink, as by immersion or other surplus applying means, the excess ink being thereafter removed by squeezing the ribbon between pressure rolls and controlling the pressure to control the amount of ink retained by the ribbon. Although this method has succeeded in distributing the ink in a more or less uniform way throughout the ribbon material, it has nevertheless had several disadvantages. such disadvantage has been due to variations in the thickness, density and absorbency of different portions of the ribbon material which have caused variations in the amount of ink retained under pressure. Another disadvantage has been that the pressure required to remove a sufficient quantity of the ink has tended to damage the ribbon fabric. Another difficulty, when employing adjacent bands of ink of different colors, has been the necessity of providing separate ink fountains and fountain rollers and squeeze rollers for each color and each width of color band, requiring complicated "and expensive equipment. A similar method has been to draw the ribbon with its surplus ink between rolls spaced apart a predetermined distance but this method has been subject to one or more of the same defects mentioned above.
One object of the present invention, therefore, is to provide an improved apparatus capable of initially and uniformly impregnating the ribbon with only the desired final quantity of ink, so as to obviate the disadvantageous complications described above.
Another object is to provide means and apparatus adapted to be readily and precisely controlled so as to suit the supply of ink to varying ribbon materials and inks.
A further object is to provide improved apparatus for simultaneously applying a plurality of bands of ink to the ribbon material to produce ink bands of the same or different ink-transferring characteristics, such as diffen ent colors or difierent intensities.
To these and other ends the invention resides in certain improvements and combinations of parts, all as will be hereinafter more fully described, the novel features being pointed out in the claims at the end of the specifica tion.
In the drawings:
Fig. 1 is a perspective schematic view of an apparatus embodying and for practicing the present invention, and
Fig. 2 is an enlarged perspective view partly in section to illustrate an ink discharge nozzle forming part of the apparatus.
We have found that the above-described objects are accomplished by providing apparatus for supplying, the
atent ink, under control of pressure, through a discharge orifice having a substantially continuous enclosing edge and supporting and feeding the ribbon with a free portion thereof in contact with the orifice edge so as to close the orifice against escape of ink except by penetrating and impregnating the ribbon as it is fed at a controlled speed and under controlled tension and pressure against the nozzle, so as to control the rate of supply of ink to the ribbon or, more precisely, the ratio by weight of impregnating ink to the impregnated ribbon material.
In carrying out this method, the selection of a suitable material serves to predetermine the factors of the porosity and ink absorbency of the ribbon. Likewise, the selection of a suitable ink serves to predetermine the factors of the surface tension and viscosity of the ink. With these factors stabilized, the remaining variables include the pressure of the ink in the discharge orifice and the rate of feed and tension or pressure of the ribbon against the orifice. Our invention is best disclosed in connection with a description of a preferred apparatus for practicing it, and such apparatus will now be described.
At 10 is a shaft adapted to support and rotate a roll 11 of ribbon material 12 of any desired width, such, in the present instance, as suitable for the reception of parallel, adjacent bands of three different colors, as red, blue and green. From the roll 11 the ribbon passes over an idler roll 13, under a brake or tension controlling roller 14 and up over another idler roller 15. The tension roller 14 is rotatably mounted on a lever 16 pivotally mounted on a spindle 17. The lever has an arm 18 extending at right angles to the arm carrying roller 14, and this angular arm is pivotally connected with a link or rod 19. Rod 19 has a collar or other suitable lengtha-djusting means 2% and its other end is pivotally connected with one arm 21 of a brake shoe 22 forming one of a pair of pivotally-connected shoes of known variety, arranged to frictionally engage and brake the rotation of shaft 10 of the ribbon supply roll. It will be seen from the above description that when tension in the ribbon falls below a desired degree, roll 14 is lowered so as to exert a pull on rod 19 and operate the brake shoes to apply resistance to the rotation of the ribbon supply roll and thus increase the ribbon tension. By adjusting the collar 20, the optimum positions of the tension roll 14 and brake lever 16 are established for automatically maintaining the desired degree of tension in the ribbon. While a tensioning device of the above character has been successfully employed, it is contemplated that other known tensioning devices may be substituted, such as a hydraulic or electric relay system, as well understood in the art, the particular details of this device forming no part of the present invention.
From the above tensioning device, the ribbon passes over an idler roller 23 and thence across and against an ink-supply nozzle head indicated generally at 24, forming part of an ink supply means and constructed as hereafter described. From this nozzle of the ink supply means, the ribbon passesover another idler roll 25 and thence between a pair of driving or feed rollers 26 and 27, rotated by means hereafter described for feeding the ribbon across the said nozzle. As shown, the idler rolls 23 and 25 are so positioned that the intermediate free portion of the tensioned ribbon is pressed against the nozzle orifices to close the same against any free discharge of ink.
The ink supply means comprises means for holding a supply of ink of each color and forcing it under pressure to the corresponding orifice of the nozzle means 24. While such supply means may obviously take various forms, we
have found it advantageous to employ a gravity head pres-- The bottom ofji each reservoir as 23 is connected by a flexible tube 31 with a passageway 32 in the nozzle head 24 (Fig. 2), each tube being controlled by a valve 33. Each container is supported in the present instance by a cable as 34 running over a pulley 35 on a spindle 36 and thence to a pulley or drum 37 rotatably supported on a standard 33 and rotated by means of a hand crank 39, as shown. By turning the crank and retracting or paying out the cable, the corresponding container is raised or lowered so as to increase or decrease the gravity head and the pressure of the ink in the discharge orifice. Each drum 37 is provided with a latching pawl (not shown) or other known and suitable means for releasably securing it in adjusted position.
The nozzle head 24 comprises, in the present instance, a block formed with discharge orifices as 40, one for each ink of different color. Each orifice is of elongated rectangular shape, having a longer dimension corresponding to the width of its color band 4-1 of the ribbon, the orifice being restricted in the other dimension, or direction of feed of the ribbon, to a small dimension so as to provide the shape of a narrow slot extending transversely of the color band of the ribbon. it is contemplated that the particular shape and area of each orifice may be varied somewhat to suit the conditions of various applications. We have found, for example, using the ink and ribbon materials referred to below, that for a color band 2 inches in width, the orifice may have dimensions of 2 inches by 0.115 inch, with an area of 0.23 sq. in. Since each orifice opens through a flat or somewhat curved, continuously smooth bottom face of the nozzle block 24, it is enclosed by a continuous edge, lying in the present instance substantially in a plane, and against which the ribbon may be pressed so as to close the orifice except by penetration and impregnation of the ribbon as it is fed under tension across and against the orifice. The several orifices are preferably separated by thin partition walls, as shown, or spaced along the direction of feed of the ribbon, so that the ink bands may be substantially contiguous as shown.
The means for feeding the ribbon across the inking orifice comprises the feed rolls 26 and 27, referred to above, which are connected by gears 42 and 43 to each other and to a driving gear 44 on the shaft 45 of a speed control unit indicated generally at 46 and which may be of any known or suitable variety, such as the known Reeves variable speed drive. This speed control unit is driven by an electric motor 47 and by such means the ribbon is fed across the inking orifice at a variably controlled speed adapted to suit particular conditions. From the feed rolls 26 and 2'7 the ribbon passes to a rewind roll 43 on a shaft 49 having a pulley i) driven by a belt 51 running over a pulley 52 on the shaft 45 of the speed controlling unit. Belt 51 and its pulleys are adapted to allow the belt to slip under tension, particularly as the rewind roll increases in diameter, so as to maintain only a sufficient tension on the rewind roll to wind up the ribbon as it is payed out by the feed rolls 26 and 27.
The present method has been disclosed in connection with the above description of the apparatus for practicing it and it is evident that, as motor 47 drives the feed rolls 26 and 27, the rate of feed of the ribbon is controlled by adjustment of the variable speed unit 46. Such feed of the ribbon on its supporting means drives it across and under pressure against the ink supply orifices under a degree of tension and pressure controlled by suitable adjustment of the tensioning device including the tensioning roller 14. With this tens-ioning device adjusted for a desired ribbon tension, any decrease in such tension allows roller 14 to fall, thereby increasing the frictional application of the braking means on shaft so as to retard the supply of the ribbon and automatically restore its desired tension. Reversely, when the tension of the ribbon rises above a desired degree, this device operates in an opposite sense to release the resistance to the feed of the ribbon and restores the desired tension.
For predetermined values of the rate of feed and of the tension and pressure of the ribbon against an orifice, the gravity head pressure on the ink at the orifice may be conveniently varied by the means described so as to precisely control the penetration of the ink into the ribbon and establish a desired ratio by weight of impregnating ink to impregnated ribbon material. Such metering of the rate of ink discharged to a predetermined volume, or to the said ratio of ink to ribbon material, becomes a matter of applying the general law of flow of fluids, namely, Q=6lKA /2gh, where Q is the discharge in cubic ft./sec., K is a constant for the viscosity of the fluid, A is the area of the supply orifice in sq. ft, g is gravity in ft./sec., and I: is the ink head in feet. Such controlled ink discharge is coordinated with the control of the tension of the ribbon, expressed in pounds per inch of impregnated width, and with control of its velocity past the orifice expressed in ft./min.
The invention has been advantageously employed, for example, with ribbons of the known cloth variety and also of the paper variety disclosed in United States Letters Patent No. 2,590,200. Such ribbons have been impregnated with black ribbon ink of the following composition:
Percent Tungstated Victoria Blue Toner 2.0 Long Flow Carbon Black 14.0 Mineral Oil (S. A. E. 30 viscosity) 60.0 Asphaltum 24.0 and with. red ribbon ink of the following composition:
Percent Barium Lithol Toner 17.0 Caster oil 33.0 Oleic acid 40.0 Butyl stearate 10.0
It has been found, for instance, that with the above paper ribbon and black ink, with a ribbon speed constant at ft./min., ribbon tension constant at 1'2 pounds/in. of width, and an orifice area of 0.23 sq. in. impregnations ranging from 61.5% to 80.7% of the weight of the impregnated ribbon material are obtained by varying the head of the ink from 18 to 44 inches. Therefore, as 1 sq. in. of such ribbon material weighs .0265 gram, the controls of the apparatus may be established as described, the gravity head of the ink supply adjusted to 32 inches and such ribbon area will be impregnated with 00198 gram of ink, which is 75% of the weight of the impregnated ribbon.
It is evident from the above disclosure that our apparatus is capable of conveniently and efiiciently impregnating' a ribbon material, with precise control of the ratio by weight of the impregnating ink to the impregnated ribbon material, and this apparatus is readily adapted and controlled to suit the different requirements of particular ink and ribbon materials.
It will thus be seen that the invention accomplishes its objects and, while it has been herein disclosed by reference to apparatus for practicing of the particular nature preferred, it is to be understood that such disclosure is intended in an illustrative rather than a limiting sense, as it is. contemplated that various modifications in the apparatus concerning details and order of such steps will readily occur to those skilled in the art, within the spirit of the invention and the scope of the appended claims.
1. An apparatus for applying ink to an ink-transfer ribbon comprising a nozzle-head having a smoothly rounded surface, a discharge orifice formed in said surface with a substantially continuous enclosing edge, mechanism for supporting and feeding said ribbon including means for feeding a tree portion thereof across and in contact with said. orifice edge to close the same around said orifice while absorbing ink therefrom, and means for controlling the ratio by weight of impregnating ink to the impregnated ribbon material comprising means for varying the pressure of ink supplied to said orifice, means for controlling the 11116 of feed of said ribbon, and means for tensioning said ribbon to exert a predetermined pressure thereof against said orifice, thereby etfecting a preselected rate of ink absorption, said lastnamed means including means for continuously regulating the predetermined pressure of said ribbon against said orifice in response to variations in the tension of said ribbon during the feeding thereof, to maintain said preselected rate of ink absorption.
2. An apparatus for applying parallel bands of ink to an ink-transfer ribbon comprising a nozzle-head having a plurality of discharge orifices each formed with a substantially continuous enclosing edge, a plurality of ink sources each supplying ink to an individual discharge orifice, mechanism for supporting and feeding said ribbon including means for feeding a free portion thereof across and in contact with said orifice edges to close the same around said orifices while absorbing ink therefrom, and means for controlling the ratio by weight of impregnating ink to the impregnated ribbon material for each band comprising means for individually varying the presagainst said orifices, thereby etfecting a preselected rate of ink absorption for each band, said last-named means including means for continuously regulating the predetermined pressure of said ribbon against said orifices in response to variations in the tension of said ribbon during the feeding thereof, to maintain said preselected rate of ink absorption.
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