US 3570380 A
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Description (OCR text may contain errors)
United States Patent Bernard Kamenstein Paramus, N .J.
June 7, 1968 Mar. 16, 1971 Ing. C. Olivetti & C.,S.p.A. lvrea, Italy  Inventor [21 1 Appl. No.  Filed  Patented  Assignee  XMPACTLESS TYPEWRITER 5 Claims, 6 Drawing Figs. 52 U.s.c| 9s/4.s 511 mu B411) 13/00 [50 Field ol'Search 95/4.5;
 References Cited UNITED STATES PATENTS 2,714,843 8/1955 Hooven 95/4.5 3,126,799 3/1964 Stauffcr 95/4.5 3,207,051 9/1965 Cooper... 95/4.5 3,220,013 11/1965 Harris..... 346/107 3,301,697 1/1967 Russell 250/65.l 3,351,948 11/1967 Bonn 250/65.l
Primary Examiner-John M. Horan Attorney-Kevin C. McMahon ABSTRACT: An impactless printing system is provided wherein a light source is used to illuminate a thermographic material through a character-shaped aperture in a mask. The light source generates enough heat in the thermographic material to cause it to be transferred, in the character shape to a receiving substrate.
TO KERR CELLS KERR CELL CONTROL ciRCbilTs N Patented March 16, 1971 3,570,380 I 2 Sheets-Sheet l 2e f l] J' f Y 4 LASER 2 KEYBOARD i?- 2 TO KERR CEL CELL RI BY (ERR CONTROL 52 1560 5. j CHQCUIT i 72 6a COUNTER 62 I ,66 L; POTENTIAL SOURCE 64 //v VENTOI? 1 BERNARD MM/Nsm/A/ T B l 5 YMK7M A 770 R/vE ys Patented March 16, 1971 3,570,380
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A FOP/V5 V5 IMZPACTLESS rvrawarrsn BACKGROUND OF THE INVENTION This invention relates to printing apparatus and more par ticularly to improvements therein.
OBJECTS AND SUMMARY OF THE INVENTION An object of this invention is the provision of a impactless printing device which can be used for the creation of originals.
Yet another object of the present invention is the provision of a novel impactless typewriter.
Still another object of this invention is the provision of a unique printing arrangement which uses light-heat energy for printing.
These and other objects of the invention may be achieved in an arrangement for a typewriter which in one embodiment substitutes for the type characters, a radiant energy source, a rotating disc which has aperture-shaped characters therein, and a typewriter ribbon coated with thermotransfermaterial. Each character-shaped aperture which is in position to be illuminatecl by the radiant energy source is detected and compared with a depressed key. If they coincide, then the source is permitted to illuminate the character-shaped aperture whereby a radiant image thereof is projected onto the ribbon coated with thermotransfer material. Heat developed from the radiant image causes the thermotransfermaterial on the ribbon to transfer to the adjacent paper. Other embodiments are also provided which use a mask having charactenshaped apertures in a moveable web 'for effectuating book printing or in a cylinder for high-speed printing.
The novel features of the invention are set forth with particularly in the appended claims. The invention will best be understood from the following description when read in con junction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. l is a diagram showing the layout of a impactless typewriter in accordance with this invention;
FIG. 2 is a plan view showing the relative positions of the essential components of the typewriter;
FIG. 3 is a schematic view illustrative of circuits necessary for operation of the embodiment of the invention;
FIG. A is a diagram illustrating a impactless web printer, in accordance with this invention;
FIG. 5 is a diagram illustrating a drum printer in accordance with this invention; and
FIG. ti illustrates a generalized arrangement suitable for use with the embodiment of the invention shown in FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENTS A layout for a impactless typewriter, in accordance with this invention, shown in FIG. I. The typewriter includes a keyboard lltl which has the same appearance and is operated in the exact same manner as the keyboard of the present day typewriters. Exemplary of the radiant energy source is a laser 12 which is permitted to emit a light flash which passes through a character-shaped aperture in a rotating disc 14, when that character-shaped aperture is in position to be illuminated by the laser beam.
The light beam which is character-shaped by reason of the mask, impinges upon a typewriter ribbon 16, which is'transported between a payout reel 18 and a takeup reel 20, using the same type of mechanism as is found in present day typewriters. Between the back surface of the typewriter ribbon and a roller 22, paper is inserted upon which printing is to occur. A power cord 2A is also shown for the machine.
Referring to FIG. 2, there may be seen a plan view of the invention. in this view, the paper 26 is shown with an exaggerated thickness, in position between the ribbon l6 and the roller 22. The ribbon is pressed against the paper by two guides respectively 23, 30.
The typewriter ribbon may comprise any suitable infrared transparent plastic material, such as Mylar, which has coated thereon on the side adjacent to the paper, a thermographic material. One may use any one of thewaxes such as a bees wax, paraffin wax, carnauba wax or obokerite wax for this purpose. These waxes are mixed when liquid, together with 5 percent of carbon black powder and 2 percent of methyviolet. One side of the ribbon is coated with the waxy mixture which is then permitted to cool thereon. The temperature at which the wax melts, and thus can be transferred to the receiving substrate, which is the paper or any other material upon which printing is desired to be effectuated, can occur at the melting temperature of the warm is well known than one can obtain waxes with melt temperatures from F! to 220 F. The temperature selected is determined by the temperature which the light source can provide at the desired speed of operation. Information on the available temperatures from the different laser light source is known, found in the literature, and available from the laser manufacturers. For example, a book which provides the available temperatures for some lasers is Optical Masers by George Birnbaum, published by the Academic Press in 1964.
The schematic view of the circuit arrangement for controlling the flash of the laser so that it will turn on only when a character-shaped aperture is in position to receive the illumination, is shown in FIG. 3. For the purposes of this invention, the laser must be strobed. A well-known technique called O-spoiling may be employed. This technique is described in the literature. As schematically shown in FIG. 3, a laser will include a ruby rod 30 which is placed within a resonant light cavity defined by two mirrors respectively 32, 34. The mirror 32 is coated to completely reflect any light that impinges thereon, while the mirror 34 is coated to reflect some of the light and pass therethrough the remainder of the light coming from the ruby rod. A- Kerr cell 36 is placed within the resonant cavity. This cell operates, in a well-known manner, to rotate the polarization of any light beam which passes therethrough when an electric field is applied thereacross. The cell is equipped with polarizing filters and therefore can be operated to permit or block the light from the ruby rod passing to the mirror 34 to be reflected back. Thus, the Kerr cell spoils the Q of the optical cavity and thereby can be used to determine when the laser is operative. The light from the laser which passes through the mirror 34 then passes through a lens 38 which insures coverage of a character-shaped aperture 40, by the light from the laser. The character-shaped aperture forms the light into a corresponding character.
A motor 42 rotates the mask 14. Centers of magnetization, represented in the drawing as spots 16, are formed in the periphery of the disc, which is made out of a magnetizable metal, by applying a localizing field to these various spots. These spots are positioned adjacent character-shaped apertures.
As the disc rotates, each spot passes by a magnetic reading head 44, consisting of a core of magnetizable metal 46 over which a winder 48 is placed. Thus, each magnetic spot passing adjacent the reading head will cause a voltage pulse to be induced in the winding 48. This is applied to an amplifier 50. The output of the amplifier is used to drive a cyclic counter 52. The counter has a count capacity equal to the number of keys in the keyboard Ml. Each key is assigned a different count. Accordingly, as the disc is rotated by the motor, and as each character-shaped aperture is lined up with the laser, the counter will have a different count condition for each character. This is indicated by the output of the counter. Each different count output of the counter is applied as one input to a different one of the AND gates 54, 56, 58. It will be appreciated that there are as many AND as there are counter outputs. Three are shown by way of example.
Each one of the keys of the keyboard It) actuates or closes a different switch respectively 64), 62, 64. All of the switches are connected from one contact to a potential source 66. The other contact of each switch goes to a different one of the respective AND gates 54, 56, 58. Accordingly, as a key on the keyboard is actuated, a switch, such as 60, is closed, whereby a potential is applied from the potential source 66 to the AND gate 541. The AND gate will not be enabled however until the counter 52 attains that count which applies an output to the other input to that particular AND gate. Such count is attained only when the character-shaped aperture corresponding to the key which has been actuated, is in position to receive the light from the laser, Whichever one of the AND gates is enabled, applies its output to an OR gate 68. The OR gate, which merely collects all the outputs of the AND gates applies a single output to the Kerr cell control circuits 70. This circuit applies a high voltage to the Kerr cell 36 over an interval required to enable the laser to generate light. The light passes through the character aperture and heats the thermographic material sufficiently to cause it to be transferred. The Kerr cell control circuit then removes the enabling voltage whereupon the laser light is turned off. The typewriter ribbon and keyboard is advanced after the character is printed in the same manner as the typewriter keyboard is presently advanced for providing an available blank space for additional printing.
FIG. 4 shows another arrangement, in accordance with this invention for printing. Here, there is provided paper which is fed from a payout roll 72 to a takeup roll 74 past a printing station defined by a pressure plate 76, opposite which there are two guide rollers respectively 78, 80. There is also fed between the guide rollers and the pressure plate a ribbon 82 which is coated with the thermographic material and also a mask 84, which is in the form of a web fed from the payout roll 86 through the printing station to the takeup roll 88. The web, in addition to having the information desired to be printed in the form of perforated characters, also carries indicia 90 which may be in the form of magnetic markings of the type discussed in connection with the disc 14, or may beholes each of which is lined up with a line of printing. If the markings are magnetic, obviously a magnetic detector will be employed. If the markings consist of holes, then a light is placed on one side of the mask and a photocell on the other. It will be assumed here that these markings are small holes and a photocell 92 is employed for detecting when a line of character-shaped apertures is at the printing position. The output of the photocell is amplified by an amplifier 94 and applied to Kerr cell control circuits 96. The Kerr cell control circuits control the Kerr cells in a plurality of aligned lasers 98, only one of which may be seen in the drawing. A plurality of lasers is used to insure that there is sufiicient illumination so that the thermographic material, which is behind each character-shaped aperture on the web 84, will be transferred to the paper.
The operation of this system should be obvious by now. A motor 100 drives the takeup rollers for the ribbon, the mask, web, and the paper, to insure synchronism. A photocell provides an output whenever it detects that a line of charactershaped apertures is at the printing'station. This causes the lasers to be triggered whereby printing occurs.
FIG. shows how this invention may be employed for printing using a drum. Here the web 102 having the charactershaped apertures is wrapped around a glass drum 104. The laser array 106 is placed within the drum. The drum is rotatably supported on two rollers 108, 110. The ribbon 112 is fed from a payout roller 114 to a takeup roller 116, passing between the masked drum surface and a backup roller 120. The paper 122 is fed from a payout roller 124 to a takeup roller 126. The detection apparatus for triggering the laser is not shown in this view, however, it is identical with that shown in H0. 4.
There has accordingly been shown and described herein a novel and useful impactless printing technique which uses light from a light source which has sufficient thermal energy to enable a thermographic material to be transferred from the carrying substrate to a receiving substrate in the shape of a desired character. While the light source which has been shown and described herein is a laser light source, those skilled in the art will appreciate that any light source capable of being strobed at a sufficiently rapid rate and capable of providing sufficient heat during the interval of strobing to effectuate the transfer of the thermographic material, may be employed in place of the laser light source, without departing from the spirit and scope of this invention. If the light source cannot be strobed, then an arrangement such as shown in H6. 6 may be used. The radiant energy source may be a source of infrared, for example.
In place of the Kerr cell, an electromagnetic shutter 132 is employed. This is operated by the output of the OR gate in FIG. 3, for example. The mask 40 is the same as the one shown in FIG. 3. Upon the character-shaped aperture which is selected reaching the printing position, the shutter 130 is operated to enable heat energy to reach the thermotransfer material to cause it to be transferred to the receiving substrate.
It will also be appreciated that while the description herein is in terms of printing on paper, this should not be construed as a limitation since one can employ the techniques described herein for printing on any object capable of receiving the thermographic material. Although particular embodiments of the invention have been described and illustrated herein, it is recognized that modifications and variations may readily occur to those skilled in the art, and consequently it is intended that the claims be interpreted to cover such modifica tions and equivalents.
1. Apparatus for effectuating impactless printing on an inert receiving substrate comprising: I
a substantially infrared transparent substrate coated with thermographic material disposed adjacent said receiving substrate with said thermographic material in contact with said receiving substrate;
a mask having a plurality of character-shaped apertures positioned adjacent said substrate carrying said thermographic material;
means for selectively illuminating with radiant energy a portion of .said thermographic material through said mask and said substantially transparent substrate;
means for successively moving said apertures of said mask between said illuminating means and said thermographic material coated substrate;
means for selectively actuating said illuminating means only when a desired one of said character-shaped apertures is positioned between said illuminating means and said thermographic material-coated substrate for melting said thermographic material on the character-shaped portion of said thermographic material-coated substrate illuminated by a said illuminating means through said desired aperture in said mask for causing said melted thermographic material to transfer to said receiving substrate in the shape of said aperture in said mask; and
playout and takeup means for transporting successive portions of said thermographic material-coated substrate between said illuminating means and said receiving substrate for causing the printing of the successive characters on said receiving substrate with thermographic material from successive portions of said thermographic materialcoated substrate.
2. Apparatus as recited in claim 1 wherein said means for illuminating comprises a laser light source.
3. Apparatus as recited in claim 1 wherein said means for actuating said means for illuminating only when a desired character-shaped aperture is positioned comprises:
a means for generating a signal representative of a character-shaped aperture in position between said means for illuminating and said thermographic-coated substrate;
a source of character representative signals;
a comparator to which said means for generating a signal and said source of character representative signals are connected; and
means for actuating said means for illuminating only when the signals received by said comparator are identical. 4. A impactless printing system comprising:
a mask in the shape of a web' having a plurality of charactershaped apertures therein; I I a ribbon in the shape of a web having thermographic material coated on one side thereof, said ribbon being adjacent said mask; a substrate in the shape of a web in contact with said thermographic material on said ribbon; controllable light means for illuminating said thermographic material-eoated ribbon through a character-shaped aperture of said mask for transferring said thermographic material in the shape of said character to said substrate; means for moving said mask, said ribbon and said substrate in synchronism with one another; and means for rendering said controllable light means operative each time a character-shaped aperture is in position to be illuminated thereby including: identifying means adjacent each character-shaped aperture; means for sensing said identifying means when said character-shaped aperture is in position to be illuminated; and means responsive to said means for sensing to render said means for illuminating operative.
v a substrate in the sha 5. An impactless printing system comprising:
a mask in the shape of a cylinder having a plurality of character-shaped apertures;
a ribbon in the shape of a web having thermographic material coated on one side thereof, said ribbon being adjacent said mask;
of a web in contact with said thermographic materi on said ribbon;
controllable light means for illuminating said thermographic material-coated ribbon through a character-shaped aperture in said cylindricalmask for transferring said thermographic material in the shape of said character to said substrate; means for moving said mask, said. ribbon and said substrate in synchronism with one another; and means for rendering said controllable light means operative each time a character-shaped aperture is in position to be illuminated thereby including: identifying means adjacent each character-shaped aperture; means for sensing said identifying means when a character-shaped aperture is in position to be illuminated; and t means responsive to said means for sensing to render said means for illuminating operative.