DE1436647C3 - Method and device for generating characters that remain visible on a recording medium - Google Patents

Description

30th

The invention relates to a method and a device for generating visible remaining Characters on a recording medium in which. depending on an electromagnetic beam, the color particles provided for the representation of the character on the recording medium Amount of energy is supplied through which the color particles are still visible during the exposure to radiation and remaining in the form of the drawing to be written are recorded on the recording medium.

A method according to the invention is intended to create the possibility of exposure to radiation To transfer characters to a recording medium in the manner of a typewriter. With usual Typewriters are required to be able to use any type of paper. Besides, he must The writing process of a single character should be at least as fast as the input with the finger Operator takes place. A typewriter should also work as quietly as possible and it must be guaranteed so that the last character written is immediately visible. However, all of these demands must can be achieved in an economically feasible manner at the price of a typewriter in To keep boundaries.

Methods are known to direct characters onto a recording medium using rays transferred to. For example, US Pat. No. 2,890,923 shows and describes an apparatus at an image generated on the screen of a cathode ray tube by means of optics onto an electrostatic one Reproduction device is projected. Using radiolucent, photosensitive Layers, a latent image is generated which, according to a special process, is recorded on a recording medium is transmitted. In this case, paint dust is deposited on the recording medium in an electrostatic field, according to the lines or characters to be depicted.

In another device, according to U.S. Patent 3,056,136, in continuous succession Lines of an image stretched on a drum are transferred to an electronic transducer. Even there the latent image is exposed to an electrostatic field using colored powder visible.

In both known devices it is necessary to have layers of different layers in front of the recording medium Provide materials or other devices that make it impossible to record immediately after recording to make the images visible. In addition, both devices can be used individually selected characters are not transferred to freely selectable writing positions on the recording medium will.

The invention has set itself the task of creating a typewriter that the initially stated Demands. It is therefore proposed that for writing in the manner of a typewriter a bundle of rays shows the characters individually selected by an input device Projected direction of arbitrarily selectable writing positions of a line of the recording medium, and that the Beams of rays on the color particles used for recording, which are on the recording medium or are on a special ink carrier, and / or acts on their holding means, and that the An amount of energy is taken from the bundle of rays, which changes the color particles chemically or physically. Color particles made of thermoplastic material on a carrier have proven to be particularly advantageous Material which, as a result of the radiation, selectively softens in accordance with the characters or liquefied and transferred to the recording medium by mechanical pressure. Included the bundle of rays can expediently in a template, according to the selected characters, be profiled.

Such a method is characterized by a high writing speed and largely noiselessness. The devices necessary to carry out the method are for the most part simple designs, so that an economical production of a typewriter which works according to the method mentioned is guaranteed. A suitable carrier for the color particles is one that consists of a radiolucent, / .. B. transparent film, which on its, the writing surface facing, with a thin, softened under the action of the beam, ■ / .. B. thermoplastic A layer of paint is provided, which holds sufficiently on the paint carrier in the cold state, but is repelled by the carrier material at the locally softened or liquefied areas. In order to keep the exposure time of the beam to soften the thermoplastic paint particles as short as possible, according to a further proposal of the invention, the paint film carrier can be preheated to a value which is just before the melting point of the paint particles.

A particularly economical method with regard to the color carrier is to be seen in it, if this, according to another proposal, is regenerable. To do this, it is advisable to move the carrier to the writing position to a known charging device for

to bring an even electrical charge, to which the following devices are connected:

a) an exposure device which illuminates the substrate at the written-off points of the ink layer and changes the electrical charge of the wearer at these points;

b) a dusting device through which the areas of changed charge in per se known Way to be provided with thermoplastic paint dust;

c) a heater for the transferred dye softens and melts it seamlessly into the unused areas of the dye layer.

This makes it possible to use an ink film carrier that is on deflection rollers at the imprint point ao passed, and after he has given up dye, can be regenerated. So it is no longer necessary Replace entire ribbons, but only need to be in a corresponding device new paint particles are refilled in due course.

Further details of the invention emerge from the claims. Patent protection is only claimed for the items characterized in the claims.

Embodiments of the invention are explained with reference to the drawing. It shows

F i g. 1 shows a basic arrangement of the main parts of a device for implementation by way of example the procedure,

F i g. 2 a device for performing the method using a band-shaped, with thermoplastic dye-coated carrier and a pressure or stop system,

3 shows a modified device according to FIG with another pressure or stop system,

4 shows an example of a device for regeneration a ribbon-shaped ink carrier by renewing the ink layer,

F i g. 5 shows another, for example, a device for regenerating a ribbon-shaped ink carrier electrostatic replacement of the copied dye particles.

In Fig. 1 a device for implementing the method is shown schematically. In this 1 is one Radiation source which is suitable for generating a bundle of primarily parallel electromagnetic beams 4 and to project onto the recording surface 3 through the stencil arrangement 2. Here is the radiant energy in the beam 4 essentially uniformly over the entire projection cross-section distributed, while the cross-section of the at the back of the roughly with blackened and transparent areas provided template 2 exiting beam 4, -f through the template a to be recorded Character is profiled accordingly. An image of the is thus created on the recording surface 3 to be recorded.

In order to achieve a sufficiently high radiation work in the area of the symbol shown in the specified printing time for influencing, d. H. for example for the discoloration of particles to represent a character To have available on the recording surface, it can furthermore be provided that the radiation source 1 z. B. is designed as a laser, which is a bundle of largely parallel radiation with a high energy content generated.

By the radiation distribution generated on the each after switching on a specific template 2 With such an arrangement, it is recording surface 3 in the simplest case of implementing the method possible, struck by the beam 4, -j To influence particles of the recording surface 3 in terms of a color change. Such a color change can e.g. B. caused by chemical discoloration of the particles as a result of energy absorption from the radiation will. However, it can also be advantageous to work with normal, unprepared writing paper and, as will be set out below, paint particles under the influence of radiation from the writing surface to be fed selectively from the outside and fixed in place.

The selection of the templates embodying a specific character can be based on electromagnetic Paths are made and controlled by a keyboard on the type of typewriter keyboards will. At the same time, pressing such a keyboard can also switch on the radiation be made with means known per se, so that each time immediately after setting a template the bundle of rays 4, -f occurs. During the change of the template can, also in known Way, the advancement of the recording surface 3 can be accomplished.

A template made of radiolucent material can also be produced using the embossing process in such a way that that the characters to be generated corresponding, arranged perpendicular to the radiation direction Levels allow the useful portion of the beam to pass through, whereas not to the direction of radiation vertical, somewhat mirrored parts of the surface of the stencil follow the unused radiation reflect outside.

Numerous other designs and arrangements of templates are also possible. So it is B. conceivable, reflection templates between the exit of the radiation generator and the writing surface to attach that the emanating from the radiation generator, parallel rays to the respective Corresponding characters, for example inclined at an angle of 45 ° with respect to the beam direction Mirror surfaces are reflected onto the recording surface arranged parallel to the beam direction. In this case too, the portion of radiation not used in each case can be from that which does not belong to the character Intermediate surfaces of the template are reflected at a different angle and therefore hidden.

Of course, z. B. caused by the type of radiation source, non-parallel beam 4 or for a reduced image of the stencil image on the recording surface, between any suitable optical means can be switched on to the radiation generator and the recording surface 3.

To further develop the method according to the invention, an arrangement according to FIG. 2 may be provided. In it, 1 is the radiation source, 2 a set of interchangeable templates, 3 the recording surface, which is made of normal writing paper, 5 a, except for a thin, thermoplastic layer 5: i radiation-permeable, e.g. made of flexible plastic, 6 a fixed magnetic coil, 7 a cup-shaped pressure or

Stop hammer with an iron ring 8 attached to the upper edge. The last two parts are held centrically to the axis of the radiation source 1 by a membrane 9 clamped in place at the edge and are attached so as to be movable in the axial direction towards the carrier strip 5 or the recording surface 3. Finally, there is a fixed counter-stop on the back of the recording surface 3 10.

The procedural mode of operation of this device is as follows: After the recording surface 3 has moved into the position provided for recording a character and a stencil of the set of stencils 2 is switched on between the radiation source 1 and the carrier film 5, the generation of the beam 4 is initiated. The beam 4a profiled by the selected template strikes the carrier film 5 and is absorbed by the thermoplastic color layer 5; i after passing through the radiolucent film part. The local heating of the thermoplastic layer, which occurs with the cross-section of the beam, corresponds in its distribution to the shape of the character to be printed and is sufficient to locally soften or liquefy the very thin layer.

It can now be provided that an adjustable, Electronic timing control of a known type after a predetermined duration of exposure to the beam 4, i on the thermoplastic layer 5 <i the magnetic coil 6 is excited. This will make the iron ring 8 is drawn into the solenoid 6 against the spring action of the membrane 9 and takes place in this Process the stop hammer 7 in the direction of the carrier tape 5 with. The carrier tape is briefly pressed against the held by the counter-stop 10 recording surface 3 and thereby transfers the accordingly locally softened paint layer on this by the characters.

By suitable means it can be achieved that the typeface transferred in this way immediately after Stop adheres to the recording surface and hardens without the carrier tape 5 on the recording surface 3 is liable. A first means of solving this problem can be that by choosing the thermoplastic material, through additives to the thermoplastic dye and / or through properties of the carrier material, the adhesion between the carrier material and the softened or liquefied Dye is reduced, or that, when exposed to heat, a substance between the thermoplastic Layer and the support is effective as a separating layer and the separation of the impact on the recording surface adhesive paint is facilitated by the paint carrier.

Another possibility is that already during the manufacture of the ribbon between the carrier and the paint layer is provided with a thin intermediate layer which, when the local heating occurs promotes the detachment of the paint layer.

The ink layer can also be made such that it adheres sufficiently to the ink carrier in the cold, cohesive state by adhesion, but is repelled by the ink carrier at the locally softened or liquefied areas. ^e 5

A further reduction in the tendency of the carrier tape to adhere to the recording surface after this has taken place Imprint of a character can be achieved in that the carrier tape is always under one Certain tensile stress is held, so that it strives immediately after the impression, again a rest distance from the recording surface 3 to be assumed.

Finally, there is the possibility of using the Andruckbzw. Stop hammer 7 by suitable electromechanical means, e.g. B. accelerated by the additional attachment of a reset winding 11 indicated by dashed lines returned to its starting position and lift the carrier tape 5 from the recording surface 3 by the suction created on its stop surface. For this purpose, it can be advantageous to provide the stop hammer with a rubber sleeve 12 or the like that forms a seal against the carrier tape when it is hit. It can also be useful to use an exact electronic control to coordinate the resetting of the hammer with the respective viscosity of the irradiated areas of the color layer 5a so that the carrier tape 5 is separated from the recording surface before the irradiated color areas have hardened. Of course, several of the measures mentioned can also be used at the same time.

In addition to the means listed, magnetically operated cutting knives are of course also available if necessary or the like. Applicable after the print has taken place without touching the print area between the ink carrier and recording surface penetrate and separate both from each other.

Compared to the device according to FIG. 2 a somewhat modified arrangement is shown in FIG. 3 shown. In this is a stop hammer 13 on the side of the recording surface facing away from the radiation generator 1 3 attached, while a radiolucent counter-stop 14 on the side of the radiation generator serves as a guide for the ink carrier 5.

This arrangement has the advantage that the stop hammer can be made simpler. aside from that can be an electrodynamic drive in a structurally simple manner as a drive for its work and return movement System 15 of known type may be provided when maximum speed is required.

The to the F i g. The device described 2 and 3 has the advantage over the known arrangements that a ribbon is used as the color carrier 5, which is at the usual extreme ambient temperatures is clean to use and completely colourfast. The ribbon can also be made so thin that that with the same reel size it results in the same writing performance as a textile tape. In addition comes that the writing noise by low-cost damping measures (rubber stop surface od. Like.) The stop hammer 7 or 13 striking only with relatively little force to an extreme minimum is reducible.

In order to switch off the slight impact of the hammer, there are of course also constructions conceivable in which, for example, one on the back of the recording surface in the imprint area parallel to this rollable pressure roller during the action of the radiation on the recording surface presses the paint carrier so that it takes over its locally softened paint particles as characters.

Since the radiation power to be used to soften the thermoplastic ink layer depends on the difference between the softening temperature ic and the ambient temperature to , preheating of the ink carrier 5 to a preheating temperature

509 610/4

for tv before it enters the recording area, the amount of heat to be supplied by the color particles from the beam is considerably reduced. While the required temperature increase is At = U-- to without preheating, when the paint layer 5a is preheated to the temperature h, a significantly lower difference value A t ¹ = u- - U is transmitted by the radiation. By choosing a suitable thermoplastic dye with a steep characteristic of its change of state as a function of the temperature A t, the area-specific radiation power to be supplied can be reduced to a minimum value.

The preheating itself can be achieved by any known heating element 16 (FIG. 3) and expediently act on the entire carrier tape 5. The supply of heat can be effective by convection or by radiation. In order to ensure the correct setpoint value of the preheating temperature u independently of the respective outside temperature, the heating output can always be kept at the correct value, for example by regulating an electrical circuit by means of a thermostat 17.

It will generally be used in future typewriters not be necessary to make copies, because duplicates are more convenient by a z. B. xerographic Copying process or can be produced by a typewriter.

However, in special cases, the procedure described should be used to be trained for the production of copies, it can be provided that between see the stop hammer 7 or 13 and the counter stop 10 or 14 recording surfaces 3 and ink carrier 5 can be inserted alternately in several layers are, and that z. B. by choosing a primarily far infrared radiation, a division of the absorption areas to the number of color carriers corresponding to the number of layers, e.g. B. Ribbons and / or strike-through foils takes place, so that after switching on the radiation pulse when the Hammer 7 or 13, the imprint of the typeface given by the beam on several recording media takes place simultaneously in the individual layers.

In the case of automatic writing machines in particular, it may furthermore be desirable to regenerate the ink ribbon consisting of the carrier 5 and the thermoplastic ink layer 5n after it has passed through the writing position. For this purpose, the carrier, as shown in FIG. 4 shows to be designed as an endless belt 5. In this case, after passing the writing position 51, it passes through, for example, an arrangement of heatable calender rollers 52, to which new dye can be fed from the storage container 54, which is also heatable. By preheating the strip in the area before it enters the roller assembly 52 by means of a heating device 55, e.g. B. an infrared heater, it can be achieved that the color layer is available again in uniform thickness and quality when it emerges from the roller arrangement.

Another type of regeneration is shown in FIG. 5.

This works on the ^{per se known 1} xerographic principle. In a device 56, the carrier is provided with an evenly distributed electrical charge. This charge is changed locally when the transcribed areas of the carrier are transilluminated by means of a light source 57. In an adjoining dusting chamber 58, the areas of the changed charge are supplied with thermoplastic color powder, which is liquefied in an adjoining heating chamber 59, so that it fits into the unused areas of the color layer and, after hardening, is available for the new writing process.

It is Z. B. possible to design at least one of the deflection devices as a mirror wheel. According to the state The latest developments also make it possible to deflect the beam by means of an optical one Make a system whose refractive index can be changed directly by deflection voltages, so that the deflection of the focal point can also be achieved without mechanically moving means.

It should also be noted that the invention Writing method, writing errors in a very similar way as with normal typewriters that can be eliminated after removal of the ink ribbon or other, procedural ink carrier from the recording area and after inserting a radiation-permeable replacement ink carrier with thermoplastic color particles in the color of the recording surface, e.g. B. in white color, by repeated writing with the wrong character, the erroneously written one is deleted Sign is possible.

When using stencils as type image carriers, additional, i. H. not stenciled characters a supplementary image carrier that can be introduced into the imprint area instead of the main carrier or the like be provided. This can consist, for example, of a piece of film with a cover layer is provided which has a radiolucent typeface. Such supplementary templates can be kept in stock in a magazine and inserted into the impression area by hand, possibly with a mechanical auxiliary device.

The supplementary stencils can also be introduced into the impression area by a mechanism Foil strips can be combined in such a way that they can be removed by shifting the strip in the direction of the lines are selectable.

Finally, an embodiment of the supplementary template is also conceivable, which od on a film strip. carries a heat-resistant top layer. Each additional layer can be added to this cover layer, for example with a stylus desired typeface can be engraved with local removal of the top layer.

The last mentioned supplementary template can also be used at the same time on the other side with a be provided thermoplastic color layer, so that the supplementary stencil without the involvement of Normally involved in the writing process or the like. Can be used.

1 sheet of drawings

Claims (1)

Patent claims: 1. A method for generating characters that remain visible on a recording medium, in which, depending on an electromagnetic beam, the one for the representation of the character An amount of energy is supplied to color particles provided on the recording medium through which the color particles are still visible during the exposure to radiation and remain in Shape of the character to be written are recorded on the recording medium, thereby marked that for writing in the manner of a typewriter, the bundle of rays (4 <i) selected individually by an input device Characters in the direction of freely selectable writing positions on a line of the recording medium (3) projects that the bundle of rays (4 <·;) onto the color particles used for recording, which are on the recording medium (3) or on a special color medium (5), and / or acts on their holding means, and that an amount of energy is removed from the beam (4; i) that chemically or physically changes the color particles. 2. The method according to claim 1, characterized in that the color particles located on the carrier consist of thermoplastic material and the radiation corresponds to the characters locally selectively softened or liquefied and by mechanical pressure on the recording medium be transmitted. 3. The method according to claim I, characterized in that for generating an electromagnetic Radiation (4) a laser is provided. 4. The method according to claims 1 to 3, characterized in that the radiation generated (4) profiled by a template (2) corresponding in each case to the typeface to be recorded will. 5. The method according to claims I to 4, characterized in that the beam generated (4) optically focused in a manner known per se and in a manner known per se by means of deflection Way is influenced so that the written image to be generated is recorded as a facsimile or raster image will. 6. Apparatus for performing the method according to claim 1, characterized in that the Carrier (5) of the color particles from a radiolucent, z. B. consists of transparent film, the on its surface facing the writing surface with a thin one under the action of the beam softenable, e.g. B. thermoplastic color layer (5. · /) is provided, which is sufficient in the cold state adheres to the paint carrier (5), but from the locally softened or liquefied areas Carrier material is repelled. 7. Apparatus according to claim 6, characterized in that that for the impression of the locally softened areas of the attached to the carrier (5) Color layer (5. · /) a mechanical or electromechanical pressure device. /. B. a stop hammer (7, 13) is provided in an adjustable time relation / um occurrence of the radiation pulse is effective. 8. Device according to claims b and 7, characterized in that by choosing the thermoplastic Materials, through additives to the thermoplastic dye and / or through properties of the carrier material, the adhesion between the carrier material and the softening or liquefied Dye is reduced, for example, that a substance when exposed to heat is effective as a separating layer between the thermoplastic layer (5. /) and the carrier (5) and the separation of the ink adhering to the recording surface upon impact from the ink carrier relieved. 9. Device according to claims b to 8, characterized in that the ink carrier (5) between one radiolucent, ζ. Β. Stop device made of glass or plastic (7) and the recording surface resting against a counter-stop (10) is guided. 10. Device according to öen claims b to 9, characterized in that the ink carrier (5) between one of the radiation source facing, radiolucent, / .. B. made of glass or plastic counter-stop (14) and the recording surface (3) out and from a clamp (13) arranged on the rear side of the recording medium can be struck against the guide. IL device according to claim 10, characterized in that that a pressure roller is provided in place of the hammer (13). the one at the back of the recording surface (3) in the impression area can be rolled off parallel to this in this way. that the recording area rests under pressure on the ink carrier (5) and its locally softened ink particles as Character takes over. 12. Device according to claims b to II, characterized in that the with a thermoplastic Color layer (5; f) provided carrier (5) before switching on the locally heating the color layer Radiation or before entering the area of the beam initiating the recording (4.7) is preheated to just below the softening point of the thermoplastic layer. 13. Device for carrying out the method according to claim 12, characterized in that to keep the preheating temperature constant fluctuating ambient temperatures a known control device is provided. the influences the resistance of the electrical preheating circuit as a function of the outside temperature. 14. Apparatus according to claim 5, characterized in that for deflecting the beam at least one optical system known per se is provided, the refractive index of which is through the deflection voltages can be influenced. 15. Device according to claims 6 to 8, characterized characterized in that for the regeneration of the color layer (5, /) of the carrier (5) in its advancing direction, then to the writing position (51), a known charging device (56) is provided for uniform, electrical charging of the carrier (5), to which the following devices connect: a) an exposure device (57), which the carrier at the written off points of the color layer x-rayed and changed the electrical charge of the carrier (5) at these points; b) a dusting device (58) through which the areas of changed charge in per se be provided in a known manner with thermoplastic paint dust; c) a heating device (59) which softens the transferred dye and transfers it into the non-useful areas of the dye layer (5; /) melts. 10 Ib. Device according to claims 6 to 15, characterized in that in connection with a method for deletion which is known in principle of incorrectly printed characters by introducing a correction ink carrier and by renewing it Hitting the false cichcns of the main ink carriers (5, 41) can be removed from the recording area and temporarily by a predominantly made of a radiolucent, with thermoplastic Dye in the color of the recording surface, e.g. B. coated a white dye Correction ink carrier, is replaceable. 17. Device according to claims 6 to 16, characterized in that additional, d. H. Non-stenciled typefaces each have a supplementary stencil that can be introduced into the imprint area is provided.