US 3854808 A
A method and apparatus for producing selected visible characters on successive portions of a recording area in which a contoured beam of radiation of an outline corresponding to the respective selected character is projected at a layer of particles maintained over the recording area so as to change the physical and/or the chemical properties of the irradiated particles and to form from the irradiated particles a visible image according to the selected character on the recording area.
Description (OCR text may contain errors)
United States Patent 0 [191 4/1956 Miller 250/319 Germer Dec. 17, 1974  METHOD AND DEVICE FOR PRODUCING 2,798,959 7/ 1959 Moncrief-Yeates 250/319 7 PRINTS AND THE K 3,121,791 2/1964 Russell 250/318 3,134,090 5/196 4 Blakely .1. 340/147 Inventor Horst Germer, Braunschweig, 3,570,380 3/1971 Kamenstein 95 43 Germany  Assignee: Trit mphwerke Nurnberg Primary Examiner john Hora Akuengeseuschafi"Numberg Att0rney, Agent, or Firm-Michael S. Striker 3 Germany 1 v i 22 Filed: Jan. 26, 1973 21 Appl. No.3 326,864 r v 5 ABSTRACT 7 Related US. Application Data A method and apparatus for producing selected visible  Communion f set. 5 59,134, J 29, 1970, characters on successive portions ofva recording area abandoned, which is a m -1h f Ser, in which a contoured beam of radiation of an outline No. 405,330, Oct. 13, 1964', abandoned. corresponding to the respective selectedcharacter is v projected at a layer of particles maintained over the-  U.S. Cl. .Q 354/5 jrecording area so as to change the physical and/or the  Int. Cl .Q B411) 13/00 chemical properties of the irradiated particles and to  Field of Search 355/3; 9'5/4.5; 250/218, form from the irradiated particles a visible-image ac- 250/219 cording to'the selected character on the recording area. I  References Cited 1 UNITED STATES-PATENTS 13 Claims, 8 Drawing Figures PA ENIEB v 3.654.808
- sumaurs INVENTOR lmnr 6510a.
ATTORNEY ever, various disadvantages. I
METIIOD AND DEVICE FOR PRODUCING PRINTS AND THE LIKE CROSS-REFERENCE To REALTED APPLlCATlQNS This isacontinuation of application Ser. No. 59,134 filed on July 29, 1970, now abandoned, which in turn is a continuation-in-part application of the copending application Ser. No. 405,330 filed on Oct. l3,..l964 for Method and Device for ProducingPrints or the Like now abandoned.
BACKGROUND OF THE INVENTION The'present invention relates to a method and apparatus for producing selected visible characters on a recording area by irradiating particles lo'cated in the region of the recording ,areawith a contoured beam of radiation of an Outline corresponding to the respective character to thereby produce from the radiated particles a visible. a
image according to the selected character on the recording area.
Most of the methods used to produce visible characterssuch as print on a recording'area used printingtypes which: are arranged on key levers, rollers or the like which are applied by mechanical or electrome- Such systems which require, besides the actual printing operation, transfer and fixing operations are expen sive and time-consuming in addition do not permit direct reading of the character produced on the recording area during the actual typing operation.
Other systems are also known in which the print or type character is first projected by opticalmeans on an intermediate carrier and fixed thereto by an electric charge. The thus-produced character is however still invisible and will become visible on the recording area onlyafter the completion of several additional method 7 stops.
chanical means against the recording area with a color carrier such as ink, an inked ribbon or the like interposed between the printing types and the recording area.'-
' These known typing'and printing means have,=how-' First-of all, the making of conventional typewriters requires a substantial amount of mechanical high precision components whose proper assembly and adjustment is expensive andrequires high-skilled labor.
Furthermore, typewriters and similar'printing apparatus'hav e a large number of relatively heavy components which, for reason of stresses they are subjected to during operation, cannot'bemade from lighter and cheaper synthetic materiaL'and the mass forces en- Besides the above mentioned prior art printing and typing devices, other systems 'for producing :visible' characters are known which, although they'include types, do not require a mechanical stroke. Such devices include for instance magnetic typing systems wherein the types are magnetically conductive and, as an -ex-- citer magnet is turned on. will produce a change of the magnetized condition'on a magnetic .carrier corresponding to the respective character to be printed. In
such systems,.however,there'will be produced first an invisible magnetized image-on an intermediate carrier, which only subsequently by powderingthis magnetized image by means of a magnetic powder will produce a visible image Onthe actual recording surface, and'such visible image has to be fixed substantially to the recording surface by heat. I
- Such systems have there forealso the disadvantage that the characters thus produced cannot be read during the actual typing or printing operation and that they require expensive auxiliary devices for'charging, powdering and cleaning of the intermediate carrier and the' transfer of the intermediate invisible image to the record carrier on which it is finally fixed in form ofa visible image.
UMMARY OF THE INVENTION i .It is an objectof the present inventionv to provid a method and apparatus for producing selected visible I characters on successive portions of a recordingarea and which avoid the disadvantagesof methods and apparatus known in the art for this purpose.
It is a further object of the present invention to provide for a method and apparatus of the aforementioned kind which can be operated at a speed far exceeding the speeds of typing and known in the art.
similar printing apparatus It is alsoan object of the present invention to provide for a methodand apparatus of the, aforementioned kind which will produce visible' characters during the actual printing operation.
It is an additional object of the "present invention to provide for an apparatus of the aforementioned kind which is relatively simple in construction so as to be produceable at reasonable cost and so as tooperate trouble-free under extensive use. I
With these objects in view, the "method-according to the present invention of producing selected visible characters on successiveportions of atleast one recording area mainly comprises the steps of positioning a selected'one of-a plurality of character forming means adjacent a selected portion of the recording'area, influencing a beam of electromagnetic radiation by the selected character; forming means so as to project a modified beam of radiation forming an outline corresponding to the selected character to be produced toward particles in the region of. the selected portion of the re-' cording area so-that-particles which are irradiated by the modified beamwill absorb part of the radiation energy so as to change the properties of the irradiated.
particles, and producing only from the irradiated particles visible characters on the recording area while the relativeposition of the beam and the recording area is maintained. v v c The change in the properties of the radiated particles may be a color change, or a softening, respectively liquifying of the particles. i I
The apparatus according to the present invention mainly comprises support means movably supporting a sheet on which thecharacters are to be produced, a source of radiation spaced from the support means for producing .a beam of electromagnetic radiation di rected toward particles located in the region of a face of'the sheet opposite the face which is supported on the support means, and a plurality of character forming means for selectively influencing the beam of radiation produced by the source of radiation so as to project a modified beam of radiation forming an outline corresponding to the selected character forming means toward a selected portion of the sheet so that particles located in the path of the modified beam will be irradiated to thereby change the properties of the irradiated particles and to produce from such irradiated particles a visible character on the portion of the sheet while the relative position of the'latter, the source of radiation and the character forming means is. maintained.
The. novel features which are. considered as .character'istic of the invention are 'set forth in particular in the appended claims. The improved device itself, however,
both as to its construction and its mode of. operation, together with additional features and advantages thereof, will be best understood upon perusal of the following detailed description of certain specific embodiments with reference to the accompanying drawing.
BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a schematic view of an apparatus according to the present invention forinfluencing a beam' of radiation produced by a source of radiation so as to project a modified beam of radiation forming an outline corresponding to a selected character toward a selected portion of a recording area;
FIG. 2 is a schematic partial view of a modified form of the apparatus shown in FIG; 1;
. FIG. 3 is a schematic view of the major components of an apparatus according to the present invention in which the particles to be irradiated are located on the recording area;.
FIG. 4 is a schematic view of a modified apparatus according to the present invention in which the particles to be irradiated are transported on a carrrier past the recording area and transferred thereto by mechanicarrier; and
FIG; 8 is a schematic view of a further apparatus according to the present invention for applying particles to be irradiated to a carrier and for transferring the irradiated particles from the carrier onto a recording area without applying mechanical pressure to the carrier.
DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention relates to a method and apparatus for producing selected visible characters on successive portions of at least one recording area. The method is carried out by positioning a selected oneof a plurality of character forming means adjacent a seproject a modified beam of radiation forming an outline corresponding to the selected character to be produced toward particles in the region of the selected portion of the recording area so that such particles will portion will pass toward the recording area.
The particles to be irradiated by this modified beam may be incorporated on the surface of the recording area, or the particles to be irradiated may be transportedin a thin layer on a radiation permeable carrier strip which is moved spaced from and longitudinally. along the recording area so that the irradiated particles in abosrbing the radiation energy are softened and then transferred by pressure-contact onto the recording area to which the softened particles will then adhere to form visible characters thereon, or the particles to be irradiated may be electrostatically charged and moved spaced from and longitudinally along the recordingarea for instance on a carrier bandso that the particles which are irradiated bythe modified beam will loose their charge and'will be transferred on to the recording area by additional electromagnetic and/orelectrostatic I attractingforce applied thereto.
.Common to the three modifications according to the method of the present inventionis a first step of modifying a beam of radiation emanating from the'source of radiation so as to project a modified beam of radiation forming an outline corresponding to the selected character to be produced toward partic les in the region of a selected portion of the recording area. As mentioned above, this is preferably accomplished by placing a se- Iected'one of a pluralityof masks or selected portions I of a single mask having cutouts or transparent portions lected portion of the recording area to thereby influence a beam of electromagnetic radiation so as to according to the selected character to be produced therein in the path of a beam of radiation emanating from a source of radiation and directed toward-the recording area. Various apparatus for placing such masks or mask portions in the path of a beam of radiation are known in the art, and FIG. 1 schematically illustrates such as apparatus.
As schematically shown in FIG. 1, this apparatus may comprise a plurality of pivotally mounted-key operated levers A, A1 and soon arranged side-by-side and each carrying a plurality of downwardly extending pins Barranged along the respective level spaced from each other according to the code different for each lever and adapted during depressing of the respective lever to close a plurality of switches C to produce in a coder in circuit with the switches coded impulses which are spectively of an outlinecorresponding to selected characters to be produced,'for instanceletters A, B,[C and so on, uniformly spaced from each other and radially inwardly therefrom a plurality of uniformly spaced slots E each corresponding. to one of the, cutouts, is rotated uniformly about a vertical axis by a motor. The disc 2 is further provided with a single additional slot F radially inwardly placed from the annulus of'slots E and aligned with one of the same. Axially aligned with the annulus of slots E and the single slot F are two lamps G and H to one side of the disc so that the rays pro duced by the lamps G and H may. pass during rotation of the disc 2 respectively through successive-slots E and the slot F onto a pair ofreceivers J respectively axially aligned with the lamps G and H' and located on the other side of the disc. The receivers J are connected to a counter K which in turn is connected to the comparator D and the latter is connected through a circuit L to a source of radiation 1. g
' The apparatus schematicallyillustrated in FIG. 1 will operate as follows: The counter K will start counting when during rotation of the disc 2 the single slot F will be in axial-alignment with the lamp l-l so that the light beam emanating from this lamp will impinge on one of the receiversJ. By depressing one of the levers ims'ec./cm" and the spectral region of the necessary rays pulses are-transmitted to the comparator D corre- .showsonly two levers A and Al, it is to be understood that the-apparatus has to'include as many levers as are cutouts for characters'to be printed on thedisc 2.
FIG. 2 shows a slight modification of the arrangement schematically, illustrated in FIG. 1 which may be used when t'he source of radiation 1, shown in FIG. 1
is continuously energized. in this modification the-circuit L is not connected to the radiation source 1, but to an electromagnet M having a movable core to which a shutter N is connected for 'movementtherewith in longitudinal direction. The shutter N has a dark'opaque portion andalight transparent portion, and this shutter is biassed by a spring '0 in the direction'of the arrow l so that normally the opaque portion will be located in the path of the beam of radiation emanating from the source 1 and so that only if the magnet M isenergized, the shutter l will'be moved against the bias of the spring!) to a position in which the transparent portion of he shutter is aligned with the rays 4 emanating from the source l.'As schematically indicated in FIG. 2 the shutter N is located closely adjacent the disc between the light radiation source 1 and the disc. The shutter N may be formed from thin sheet metal and the transparent portion thereof may simply be a cut out formed in ator l, a masking-arrangement 2-, which-may be con-' themask 2 is interposed between a radiation generator land a record carrier 3 which carries on the face thereof facing the radiation generatorl a layer of particles fixed thereto which are to beirradiated by the modified beam 4a. g
In this embodiment the record carrier 3 is a radiation sensitive paper provided with a layer of particles fixed thereto which change their color whenirradiated by the modified beam 4a. Such radiation sensitive papers are well known in the art and for instance described in the US. Pat. No. 3,028,254 to Edwin Allen Grant, Jr.
When such papers are subjected to ultraviolet rays emanating from the radiation generator 1, the portions radiated by the modified beam 4a will change their color by absorbing the energy of the radiation. Paperswith a particle layer sensitive to ultraviolet radiation will require a radiation intensity of 20 microwatt is for ultraviolet sensitive papers in the region of 150 350 nanometer. v
Other papers sensitive to heat rays are also described in the US. Pat. No. 2,953,454 which describes a paper provided with a layer composed of the following ingredients: v
Ingredients Parts by Weight I Camaub'a wax I l l Ouricury wax 4 Lanolin 7 Blown rapseed oil 8 'Mineral oil ll Crystal violet ,dyestuff 59 Such papers are to be irradiated with a radiation intensity of 50- lSO milliwatt sec/cm and the spectral region for such papers should"bebetween 800 and 2,000 nanometer. I
As radiation generators for the spectral region of l50-' 350 nanometers discharge lamps or, flash lamps are suitable whereas for the spectral region of 800 2,000 nanometer incandescent lamps or infrared lamps tion is schematically illustrated in FIG. 4. The embodiment shown'in this Figure comprises a radiation generstructed as described abovein connection with FIGS. 1 and 2,'for inserting a selected one of a plurality of cutouts or transparent portionsof an outlinecorresponding to the selected character to be printed into the path of the rays 4 emanating from the radiation generator so as to provide a moified beam of radiation 4a downstream of the mask. This modified beam 4a passes through the, bottom wall of'a pot-shaped ham mer 7 which is transparent and for instance formed of glass, preferably of Plexiglass, and through formed of glass, preferably of Plexiglass, and through a likewise transparent carrier band 5 held in taught condition, by means not shown in the drawing, against the .bottom face of the pot-shaped hammer 7. The carrier band 5 is formed from a flexible plastic material, for instant polytetrafluor-ethylene is preferably used instead of polyvinyl chloride, The bottom face of the carrier band carries a thin opaque layer of thermoplastic material 5a which may consist of carbon black enclosed in wax. Such layer material is known in the art and it may for instance include 40 parts by weight of carnauba wax, 40 parts by weight of mineral oil and I5 parts by weight of carbon black. I
Other materials usable for thispurpose may be composed of 36 parts by weight of carnauba wax, 1 part by weight of ozokerit, 40 parts by weight of mineral oil, 5 parts by weight of oleic acid, 3 parts by weight of crystal violet, and parts by weight of carbon black. This material will, soften when radiated by the modified beam 4a and the softened parts of this layer 5a will then betransferred by pressure contact onto the recording surface 3 which in this case may be standard paper. A stationary stop 10 is provided abutting against the bottom face of the paper 3 and this stop may be formed from any suitable material, for instance, metal.
The pot-shaped hammer 7 carries fixed to the upper rim thereof in any suitable manner an iron ring 8 to which a flexible membrane 9, fixedly mounted at the cuter periphery thereof on a stationary support, is connected to thus yieldably holdthe ring 8 and the hammer 7 connected thereto in arestposition andcentrally with respect to the radiation generator 1. A stationary magnet coil 6 is arranged coaxial with and downwardly spaced from the ring 8 so that the latter will be downwardly moved against the tension of the membrane 9 when the coil' 6 is energized.
The above-described arrangement will operate as follows: After advance of the paper 3 into the position for printing a selected character thereon and simulta-.
neously movement of the mask 2 to bring a selection generator 1, the generator 1 is energized so that a modified beam of radiation 4a will pass through the carrier band 5 whereby the layer 5a thereon will be locally heated according to the outlined the modified beam 4a, that is according to the outline of a selected character to be printed. The energy absorbed by the irradiated portion of the layer 50 will be sufficient to locally soften, respectively liquefy this layer.
An adjustable electronic time delay of known construction may be provided to energize the magnet coil 6 after the modified beam of radiation has acted for a predetermined time on the thermoplastic layer 5a to thereby draw the iron ring 8 against the bias of the membrane 9 into the coil 6 so as to momentarily press the carrier band 5 and the layer 5a on the bottom face thereof against the top face of the paper 3, which will transfer the locally softened portion of the layer 5a corresponding to the selected character onto the paper 3.
By the. provision of proper means it can be assured that the transferred character will'stick to and harden, respectively solidfy on the paper 3 without causing the carrier band 5 to adhere to this paper. The abovementioned materials for the carier band 5 and for the layer 50 thereon will satisfy this requirement.
The necessary radiation intensity required for carrying out the method with the above-described embodiment is in the range of I00 milliwatt sec/ cm and the spectral region for the necessary radiation is in the region of 800 2000 nanometer. Incandescentlamps or infrared lamps are especially suitable as radiation generators in this case.
In order to reduce the surface tension of the carrier band 5 when the latter is formed from polyvinyl chloride it is preferred to apply to the bottom surface of the carrier band 5 a very thin layer of polytetrafluorethylene, respectively to form the carrier band 5 from the last-mentioned material, Polytetrafluoethy- .lene has, as well known, a very small surface tension.
It is also possible to accelerate the return movement of the hammer 7 to its rest position as shown' in FIG. 4 by providing an additional solenoid-coil ll; upwardly spaced from the solenoid coil 6 which whenenergized will quickly lift the hammer'7 so that by the suction thus created on the bottom face of the hammer the carrier band 5 will be quickly liftedfrom the paper 3. For
this purpose it may also be advantageous to .provide at the bottom of thehammer 7 a rubber sleeve .12 which fluidtightly' engages the upper surface of' the carrier band 5. It is further advantageous to provide for energizing of the magnet coil 7 an exactly adjusted electronic control arrangement of known construction which will cause movement of the hammer 7 to its rest position at time in which the portion of the layer 5a transferred to the paper 3 is not fully hardened so that separation of the carrier band 5 and the paper 3 will occur before the hardening of the radiated layer portion 5a which is transferred onto the paper 3.
FIG. 5 illustrates schematically a furtherembodiment according to the present invention which 'will operate in a manner similar to the embodiment described above in connection with FIG. In this embodiment theposition of the hammer l3 and the stop 14 are reversed as compared to the arrangement shown in FIG. 4, that is the stop 14 is'arranged to engage the top face of the carrier band 5,'whereas the hammer 13 is arranged to engage thebottom face of the recording papers 3. In this'case the stop 14 has evidently to bemade of transparent material and it is preferably formed from Plexiglass. The arrangement shown in FIG. 5 has the advantage that the construction of the hammer 13 can be simplified. In addition it is possible to provide'forthe drive of the hammer for its working and return stroke an electrodynamic system 15 which will assure amaximum speed of the hammer movement.
The arrangement according to FIG. 4 and 5 has the advantage that a carrier band and the color layer 5a thereon may be used which during normal room ternperature will not smudge and be color-fast.
Since the radiation energy necessary forsoftening respectively liquefying portions of the layer 5a will depend on the difference between the softening'te'mperature t. and the temperature t of the surrounding atmosphere, it is possible by preheating the carrier band 5 to a preheating temperature 1, before it passed in the region of the radiation beam emanating from the generator 1 so that the amount of heat to be transmitted to he particles of the layer 5a by the beam 4a may be considerably reduced. For this purpose a heating element Usually it is assumed that it is not necessary to pro-' I duce carbon copies withthe embodiments illustrated in FIGS. 4 and 5 since copies can be made in a simple ner as-described-above in connection with FIG. 7 and manner with known-copying processes. If, however, in
special cases the described method should be used for the production of carbon copies, then it is possible to introduce between the hammer 7- respectively 13 and the stop 10, respectively 14 a plurality of carrier bands 5 with the layers 5a thereon and recording papers 3 alternately sandwiched therebetween in a plurality of layers so that for instance by selection of proper heat radiation a division on the plurality of layers will occur so that after energizing the radiation generator and movement of the hammer 4 respectively 13 along its working stroke a simultaneous printing of the desired character delineated by the beam of radiation 4a will occur in the various layers.
FIG. 6 -schemati cally illustrates an arrangement to regenerate the layer 5a on the carrier band 5. For this purpose, the carrier band 5 may be in the'form of an endless band guided by guide rolls as shown in FIG. 6 about an endless path and movable in the direction as indicated by the arrow. After passing the printing position 51 schematically indicated in FIG. 6, the band5 passes heatable calender rolls 52 which apply from a likewise heatable container 54 a new layer 5a of the composition as mentioned aboveto the band 5. Before entering the calender arrangement 52 the band 5 may be preheated by a heating device 55 which will assure that the layer 5a will be applied with uniform thickness to theband,
FIG. 7 schematically illustrates another arrangement for regeneratingthe layer 5a on the'carrier band 5.
jThis arrangement actssimilar to the known xerographic principle. The endless carrier band 5 after passing, through the printing position 51, schematically shown in .FIG. 7, passesbeneath an electric charging device 56 which for instance may apply a positive charge to the carrier band 5. The thus charge band passes above a radiation source 57 which-due to the radiation will neutralize thecharge imparted to the band at such position of the latter at which the printing layer has been removed in .the printing position of the band. The band passes thereafter beneath a powdering chamber 58 in which likewise positively charged thermoplastic color powder is applied to the band which will stick to the latter only at a portion thereof in which no charge remains since at the other portions the positivelycharged band and the positively charged particles will repulse each other. This powdered band is then passed by a heating chamber 59 in which the newly applied powder is liquefied to form with the remaining portions of the layer 5a a uniform uninterrupted layer which isthen passed again to the printing station 51.
Color powders suitable for this process are for instance disclosed in the reissue U.S. Pat. No. 25,136 or in the U.S. Pat. No. 2,659,670.
thereafter the band passes adjacent-a spraying device 43 in which a thermoplastic powder of acomposition as mentioned above in connection with FIG. 7 is uniformly applied against the outer surface of the band and due to the charge applied to the band the powder will adhere to the latter. When the thus prepared band passes into the printing position in which modified beam passes through the band 41 and onto the powder layer applied thereto, the electric charge applied to the band will collapse at the portion thereof impinged by the modified beam of radiation and at three portions the powder particles will move under the influence of the order of -50 microwatt sec./cm whereas for the FIG. 8 illustrates a further embodiment according to I the present invention.
This embodiment'includes alsoan endless carrier band 41, a portion of which is guided for movement in the direction as indicated bythearrowparallel toand adjacent to the recording surface 3 which in the case may also be standard writing paper. The moving band passes upstream of the beam of radiation emanating from the radiation generator .1, which is modified by passing through the mask 2, first through an electric second step irradiation energy in the order of 50-150 milliwatt sec./cm is required. The spectral region for the first step should be in the order of -700 nanometer and for the second step 800-2000 nanometer. For the first step gas discharge lamps or incandescent lamps are best suitable and for the second step incandescent lamps or infrared lamps are best suitable. I
As material for the band 41, the materials mentioned in connection with FIGS. 4 and 5 are suitable and a band material as described in the U.S. Pat. No. 3,392,642 may also be used in the embodiment as shown in FIG. 8. i
The embodiment described in connection with FIG. 8 has somesimilarity with the xerox copying methods, for instance described in U.S. Pat.No. 2,735,785, 3,166,420, or 3,301,152.
The embodiment shown in FIG. 8 has the advantage that no hammer is provided so that the method carried out therewith is completely noiseless. v
Instead of the radiation generators mentioned in'connection with the various above-described embodiments, it is also possible to use a laser as radiation gen-- erator. Such lasers are advantageously used since they have very advantageous switching characteristics and produce a very high radiation energy. Radiation generators such as low pressure gas-discharge tubes, light emitting diodes, lasers and microwave, oscillators may be directly electrically controlled so that such radiation generators may be used in connection with the control arrangement shown'in FIG.,.1, whereas other radiation generators such as high'pressure gas-discharge tubes, incandescent lamps or infrared-lamps have to be used with an arrangement as described above in connection with FIG. 2 in which a shutter isused to control the tails shown, since various modifications and structural changes may be made without departing .in any way from the spirit of the present invention.
Without-further analysis, the foregoing will so fully reveal the gist of the present invention that others can be applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects'of this invention and, therefore, such adaptations should and areintended to be comprehended within the meaning and range of equivalence of the following claims. What-is claimed is new and desired to be protected by letters Patent is set forth in the appended claims.
1. A method of producing selected visible characters ,12 modified beam of radiation forming arr-outline corresponding to the selected character forming means toward a selected portion of said sheet so that said partiand therespective character forming means which has on successive portions of at least one recording area,
comprising the steps of operating a selected one of a plurality of key means for positioning a selected one of a plurality of character forming masks adjacent a selected portion of the recording area; influencing a beam of'thermal radiation by the selected character forming mask so as to project a modified 'beam of radiation having an outline corresponding to the selected I character to be produced toward colored particles which soften when irradiated and which are connected to one face of a band facing said recording area; moving said band in a first direction substantially parallel to and spaced from said recording area through said modified beam so that the particles which are irradiated by said modified beam will softemand moving a portion of said band on which said irradiated particles are located' and an opposite portion of said recording area relative to each other in a second direction transverse tosaid first direction so that said irradiated softened particles will contact and adhere to a selected portion ofsaid recording-area to thus produce visible characters thereon.
2. A method as defined in claim 1, wherein said sec- 0nd moving step comprises thestep of flexing said portion of said band toward said selected portion of said recording area.
3. A method as defined in claim 2, wherein said flexing of the band is carried out by imparting a sudden blow onto saidportion of said band, after particles thereon have been irradiated and softened by said irradiation.
4. A method as defined in claim I, and including the step of preheating the band prior to the movement of said portion thereof over said selected portion of said recording area to preheat the particles on the band to a temperature below the softening point thereof.
5. Apparatus for producing selected visible characters on successive portions of at least one recording area comprising, in combination, support means movably supporting a sheet on which the characters are to be produced; a source of radiation spaced from said support means for producing a beam of electromagnetic radiation directed toward particles which change their properties when subjected to electromagnetic radiation and which are located in the region of the face of the sheet opposite the face which is supported on said support means; a plurality of character forming means for selectively influencing the beam of radiation produced by said source of radiation; means including means into the path of said. beam so as to producea maintaining the latter in said rest position. '9. Apparatus as defined in claim 8, wherein said biascles located in the path of said modified beam will be irradiated to thereby-change the properties of the irradiated particles and produce from said irradiated particles a selected visible character on a portion of said sheet, while the relative position of said sheet, said source of radiation, andsaid character forming means are maintained; means for transporting said particles in a layer of particles between said one face ofsaid sheet of said band which faces said one face of said sheet; and
means for transferring the irradiated particles from said band onto said one face of said sheet and comprising means for flexing a portion of said band located in the path of said beam of radiation toward said one face of said sheet so as to transfer the irradiated particles tothe latter, said flexing means comprising a member of radr ation permeable material arranged between said means for producing said beam of radiation and said band and movable from a rest to an active position. deflecting said band, and means for moving said member suddenly from said rest to said active position. 1
6. Apparatus as defined in claim 5, wherein said parv ticles are color particles whichsoften when irradiated.
7. Apparatus as defined in claim 5, wherein said member is cup-shaped member having an upper rim and'a bottom wall facing the surface of said band opposite the surface of the latter to which said particles are" applied, and. including an annular component of magnetizable material fixed to said rim of said cup-shaped member, and wherein said means for moving'said member comprises solenoid'means cooperating with said component of magnetizable material.
8. Apparatus as defined in claim 7 and including biassing means connected to said member for yieldably ingmeans comprises a'flexible' membrane connected at a central portion thereof to said member and fixedly mounted at the periphery thereof on a stationary support.
' 10. Apparatus as defined in claim 8 and including additional solenoid means cooperating with said magnetizable component for returning said member at accelerated speed to said rest position.
11. Apparatus as defined in claim 10, and including prior to the radiation of said particles, to a temperature below the softening temperature.
13. Apparatus for producing selected visible characters on successive portions of at least one recording area comprising, in combination, support means movably supporting a sheet on which the characters are to be produced; a source of electromagnetic radiation spaced from said supporting means for producing a' beam of electromagnetic radiation toward particles which change their properties when subjected to thermal radiation and which are located adjacent a selected portion of one face of the sheet opposite the face which is supported on said support means; a plurality of character forming means for selectively influencing the beam of radiation produced by said source-of electromagnetic radiation; means for transporting said particles in a layer of particles between said one face'of said sheet and a selected one of said plurality of character forming means, said means for transporting said layer comprising an endless band movable in one direction; means outside the path of the beam of radiation for electrically charging said band; means for applying said particles in a layer onto the surface of said band which during movement of the latter faces said one face of said sheet; and means including a plurality of in dividuwhile the relative position of said sheet, said source of radiation and said character forming means are maintained.