US3048695A - Copy method and apparatus - Google Patents

Copy method and apparatus Download PDF

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Publication number
US3048695A
US3048695A US821943A US82194359A US3048695A US 3048695 A US3048695 A US 3048695A US 821943 A US821943 A US 821943A US 82194359 A US82194359 A US 82194359A US 3048695 A US3048695 A US 3048695A
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United States
Prior art keywords
copy
sheet
wax
letters
radiation
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US821943A
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English (en)
Inventor
Robert B Russell
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Warren SD Co
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Warren SD Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority to NL252898D priority Critical patent/NL252898A/xx
Application filed by Warren SD Co filed Critical Warren SD Co
Priority to US821943A priority patent/US3048695A/en
Priority to FR830647A priority patent/FR1260420A/fr
Application granted granted Critical
Publication of US3048695A publication Critical patent/US3048695A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41M—PRINTING, DUPLICATING, MARKING, OR COPYING PROCESSES; COLOUR PRINTING
    • B41M5/00—Duplicating or marking methods; Sheet materials for use therein
    • B41M5/26—Thermography ; Marking by high energetic means, e.g. laser otherwise than by burning, and characterised by the material used
    • B41M5/382—Contact thermal transfer or sublimation processes
    • B41M5/38207—Contact thermal transfer or sublimation processes characterised by aspects not provided for in groups B41M5/385 - B41M5/395
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41L—APPARATUS OR DEVICES FOR MANIFOLDING, DUPLICATING OR PRINTING FOR OFFICE OR OTHER COMMERCIAL PURPOSES; ADDRESSING MACHINES OR LIKE SERIES-PRINTING MACHINES
    • B41L19/00—Duplicating or printing apparatus or machines for office or other commercial purposes, of special types or for particular purposes and not otherwise provided for
    • B41L19/003—Duplicating or printing apparatus or machines for office or other commercial purposes, of special types or for particular purposes and not otherwise provided for using heat, e.g. wax transfer
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B27/00—Photographic printing apparatus
    • G03B27/02—Exposure apparatus for contact printing
    • G03B27/14—Details
    • G03B27/30—Details adapted to be combined with processing apparatus
    • G03B27/306—Heat development

Definitions

  • This invention relates to copying methods and apparatus, and more particularly to a process and apparatus for producing copy from black or essentially radiant energy absorbent letters on paper or the like.
  • My invention stems initially from the discovery that, when a piece of paper carrying black letters thereon is placed in contact with another piece of paper placed over the letters, and when this combination is subjected to radiation (i.e. heat-producing light rays) under conditions in which the radiant energy passes through the copy sheet and heats the surface of the black letters more than the surrounding areas of white paper, it is possible to make a substantial portion of the surface heat of the letters pass back up through the copy in the form of radiant rather than conducted heat.
  • radiation i.e. heat-producing light rays
  • a second fact of basic importance in understanding my invention relates to the degree of absorbency of and/or transparency to radiant energy by various materials at various wave lengths of radiation.
  • Paper is relatively transparent to radiation having a wave length of 1-3 microns, but highly absorbent to radiation longer than 5 microns.
  • Chemical Engineers Handbook (1941) paper is very close to a perfect black body (.924 to .944) when exposed to black body radiation at a temperature of 66 F. Since lamp black at 68 F. is rated in the same range (i.e. .927 to .967), paper and lamp black may be regarded as equally absorbent of the type of radiation a black body emits at low temperatures.
  • the resulting cop-y has excellent definition when the refinements of my invention are practised.
  • the copy is permanent.
  • the letters on the copy comprise a layer of dyed wax, and as such they are as permanent as most inks and far more permanent than pencil or soft carbon copy.
  • the cost of such copy is extremely low involving no more than the cost of a single light weight sheet, plus the cost of a wax coated sheet containing a special dye.
  • the cost is substantially less than one-half the cost per copy of the conventional process sold by Minnesota Mining and Manufacturing Co. under the name Thermofax which I understand is the least expensive comparable dry process now on the market.
  • my process can copy a conventional letter-sized sheet (8% x 11") in less than two seconds.
  • a number of precautions should be taken if optimum copy is to be produced. For instance, care must be taken to avoid heating up the wax transfer and copy sheets by the applied radiation any more than necessary. This is done first, by selecting a light source rich in radiation of a wave length which more readily penetrates wax and paper. It is likewise preferable to permit the light to pass a substantial air gap prior to reaching the wax transfer sheet. This tends to eliminate some of the upper portion of the spectrum and helps render the radiation more uni-directional. Of course, a wax and dye combination which is especially transparent to the applied radiation should be selected. The thickness of the wax transfer and copy sheets is likewise an important consideration.
  • Another feature of my invention relates to the duration of contact between the Wax transfer sheet and the copy sheet. It will be understood that my invention may be practised even though an excess of heat is actually stored or accumulated in the letters during exposure. Under such conditions the sharpness of the letters can be preserved by separating the wax transfer sheet from the copy sheet before the stored or accumulated heat has had a chance to spread or pass through the copy in the unwanted areas. This is a feature of both the process and the apparatus of my invention.
  • Still another feature of my invention relates to the closeness of contact between the original, copy sheet and Wax transfer sheet, and the point at which in the process such closeness of contact is important. Since the applied radiation is relatively penertating, closeness of contact is not particularly important in connection with selectively heating the letters. However, since the counter-radiation from the original letters spreads in all directions at once and since the counter radiation starts almost as soon as the applied heat starts, it is desirable to keep the copy and wax transfer sheets relatively close during exposure. However, extremely close contact at such times is not critical and a feature of my invention illustrating this is that deeply imprinted black letters, which never touch the copy at all, result in just as good coppy by my method as black letters which are flush with the surface of the original. Extremely close contact, however, is important immediately after exposure to the light. Once the Wax is melted, or softened enough to transfer, a complete and uniform contact between the transfer and copy sheets is highly desirable, and it is a feature of my invention that I provide the same.
  • FIG. 1 is a cross sectional view in side elevation taken through the center of the apparatus of my invention
  • FIG. 2 is a partially exploded view in perspective illustrating essentially the same elements shown in FIG. 1;
  • FIG. 3 is an enlarged view in cross section and side elevation of the light, reflector and printing roll
  • FIG. 4 is an enlarged vie-w of the original, copy sheet and wax transfer sheet employed in my invention.
  • FIG. 5 is a graph illustrating certain aspects of the operation of my invention.
  • the preferred embodiment of the apparatus of my invention herein shown includes in its general organization a base 10 supporting side walls 12, which serve in turn to support in suitable bearings a series of rolls for feeding the elements of the copying combination through the machine.
  • These rolls include a wax transfer sheet supply roll 14 carrying a supply of wax transfer sheet 15, a copy sheet supply roll 16 carrying a supply of copy sheet 17, a wax transfer sheet retarding roll 18 operatively engaged by a pressure roll 20 to grip the wax transfer sheet 15 against the retarding roll 18, a printing roll 22, a light source indicated generally at 24, an idler roll 26, a wax transfer sheet drive roll 28 driven by a motor 30, and a pressure roll 32 operatively engaging drive roll 28 to grip and drive the wax transfer sheet 15.
  • the rotation of the retarding roll 18 is limited by a friction brake arrangement indicated generally at 34.
  • the wax paper is threaded through the machine, around the retarding roll 18, under the printing roll 22, between it and the light source 24, over the idler roll 26, and thence between the drive roll 28 and its pressure roll 32. From this point the wax transfer sheet 15 issues to waste through an exit chute 36 in the rear of the machine.
  • the copy sheet 17 is fed forwardly from the roll 16 on top of the wax transfer sheet 15, between it and the printing roll 22, and thence outwardly towards the front of the machine to an exit opening 38.
  • a small take-off roll 40 is employed to insure separation of the copy sheet 17 from the wax sheet 15 immediately after the two have passed adjacent to the light source 24.
  • a cut-off knife 42 is provided adjacent to the opening 38 for the purpose of cutting the copy sheet 17 to appropriate length when a copy has been made.
  • An original to be copied is indicated at 44 and is introduced through a slot 46 in position over the copy sheet 17 from which point it is likewise fed under the printing roll 22 and issues along with the copy sheet from the opening 38.
  • the wax transfer sheet 15 is placed with its coated side adjacent to the copy sheet 1'7, and the original 44 is likewise placed with the letters to be copied thereon facing the other side of the copy sheet 17.
  • the radiation penetrates down through the transfer sheet 15 and copy sheet 17 to the surface of the original 44 where the light selectively heats the surface of the letters on the original to a greater extent than it heats the background areas on the surface of the original.
  • the letters reradiate heat backwardly through the copy sheet 17 to the wax sheet 15, melting the same and thereby preparing the same for transfer to the copy sheet in the areas of the letters.
  • I employ an infra-red lampsold by the General Electric Company under the designation l000T3, which lamp is adapted to operate at 220 volts for normal operation. I find, however, that at such a voltage this lamp emits a spectrum which is overly absorbed by the wax transfer and copy sheets. Preferably I operate the lamp at 440 volts, and for some uses it may even be preferable to operate the lamp at higher voltages.
  • the lamp is indicated at 48 in FIG. 3. I also position the lamp 48a substantial distance (i.e. 1 /2) away from the printing roll 22. At this distance it is necessary to employ a pair of reflectors 5!
  • the reflectors 50 concentrate the radiation from the lamp 4'8 primarily at a point X and in a direction generally normal to the tangent of the roll 22 at that point.
  • the wax transfer sheet As the light strikes the wax transfer sheet, it penetrates through it and through the copy sheet where it heats the surface of the letters on the original. These letters are indicated at 54 in FIG. 4. It will be understood, of course, that even the smallest letters are substantially wider than the sheets are thick. In the preferred embodiment of my invention the wax transfer and copy sheets are approximately .0015" in thickness and, as shown. in FIG. 4, the letter 54 being 10 times as wide as the sheets are thick, still represents about as small a thickness of letter as will be found in fine printing. As the light strikes the surface of the letter 54, it immediately heats the top thereof to relatively high temperature.
  • the smoothness of the surface of the copy sheet and transfer sheet is important in order to provide good wax transfer from the transfer sheet to the copy, but smoothness is also important for a less obvious reason. Since the return radiation from the letters is readily absorbed by the copy, certain portions of the copy immediately adjacent to the letters 54 reach a temperature higher than that of the wax transfer sheet surface in the area A. This undoubtedly acccounts for some lateral spreading due to conduction. In addition, the heated air in and adjacent to the copy is also capable of spreading the heat, and if the interface between the copy and the wax is rough, then the heated air will be squeezed laterally along the copy when the transfer pressure is applied thereto.
  • one drawback of the preferred embodiment of the apparatus herein shown is that it cannot make a copy from a page of a book because the original must follow around the roll 22..
  • This problem can be met by a device arranged to hold the page flat under vacuum and then passing the light source 24 over the page. I have done this with the light source and reflectors mounted on a moving unit which traverses the page at a measured rate during exposure. Quick separation can be arranged on such a unit by mounting a take-up reel for the used transfer sheet on the moving unit.
  • the motor 30 is provided with a variable speed mechanism.
  • the power source for the lamp 48 is provided with a rheostat in series so that minor adjustments in the intensity of the light can be made.
  • I find that the air surrounding the lamp 48 and the reflectors 50 tends to absorb heat, and as the machine stands idle this air as Well as the lamp and reflectors themselves tend to radiate heat into the area X of the printing roll 22.
  • the fan 52 is adequate to convey such unwanted heat away from the area X.
  • the graph shown in FIG. 5 is only illustrative, and is used primarily as a means of quick explanation of the problem. A more careful analysis, however, of the temperature sequences of the various components of the problem should be considered.
  • the entering radiation is absorbed relatively uniformly throughout the wax transfer sheet and the copy.
  • the white areas of the original reflect some of the applied radiation back towards the transfer sheet While the black area do not.
  • the surfaces of the letters commence heating up and re-radiating; but for a short additional period this reradiation is predominantly of such long wave length that little, if any, of it may be regarded as penetrating the copy and reaching the area A.
  • the surface temperature of the letters soon increases so rapidly that the return emission from the letters is of suflficient intensity and of short enough wave length to penetrate the copy and contribute significantly to melting the wax. If the applied radiation is then continued various things happen.
  • the surface temperature of the letters can rise too high and damage the original.
  • the letters and heated portions of the copy can store too much residual heat, thus causing heat spreading of the letters unless quick separation precautions are taken.
  • a process for copying radiant energy absorbing indicia on an indicia bearing sheet comprising: placing said indicia bearing sheet on a curved surface; placing a copy sheet over said indicia; placing a transfer sheet having a thermoplastic coating thereon over said copy sheet; drawing said transfer sheet into intimate contact with said copy sheet and pressing the same against said indicia bearing sheet by maintaining said transfer sheet under tension; both heating said transfer and copy sheets and causing heat from said indicia to cross the gap between said indicia and said copy sheet, to pass through said copy sheet, to cross the gap between said copy sheet and said transfer sheet and additionally to heat up said transfer sheet by directing incident radiation through said transfer and copy sheets to the surface of said indicia; and continuing said incident radiation only until the combined effect of it and said heat from said indicia melts said coating on said transfer sheet, whereby said coating transfers from said transfer sheet to said copy sheet in areas corresponding only to said indicia.
  • a process for copying radiant energy absorbing indicia on an indicia bearing sheet comprising; placing said indicia bearing sheet on a curved surface; placing a copy sheet over said indicia; placing a transfer sheet having a thermoplastic coating thereon over said copy sheet; drawing said transfer sheet into intimate contact with said copy sheet and pressing the same against said indicia bearing sheet by maintaining said transfer sheet under tension; both heating said transfer and copy sheets and causing heat from said indicia to cross the gap between said .indicia and said copy sheet, to pass through said copy sheet, to cross the gap between said copy sheet and said transfer sheet and additionally to heat up said transfer sheet by directing incident radiation against the exposed back of said transfer sheet and through said transi2 fer and copy sheets to the surface of said indicia; and continuing said incident radiation only until the combined effect of it and said heat from said indicia melts said coating on said transfer sheet, whereby said coating transfers from said transfer sheet to said copy sheet in areas corresponding only to said indicia.
  • the copying process defined in claim 4 further characterized by continuously passing said transfer, copy and indicia bearing sheets past a radiation application zone; and shortly thereafter continuously separating the transfer sheet from the copy sheet after passage through said radiation application zone.
  • a process for copying radiant energy absorbing indicia on an indicia bearing sheet comprising: placing said indicia bearing sheet on a smooth surface; placing a copy sheet over said indicia; placing a transfer sheet having a thermoplastic coating thereon over said copy sheet; continuously passing said so positioned sheets through a radiation application zone to heat said sheets and selectively melt said coating and cause it to transfer said copy sheet in areas corresponding to said indicia; and thereafter continuously separating said transfer sheet from said copy sheet at a given point shortly beyond said radiation zone by drawing said transfer and copy sheets in divergent directions.

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  • Physics & Mathematics (AREA)
  • Optics & Photonics (AREA)
  • General Physics & Mathematics (AREA)
  • Thermal Transfer Or Thermal Recording In General (AREA)
US821943A 1959-06-22 1959-06-22 Copy method and apparatus Expired - Lifetime US3048695A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
NL252898D NL252898A (US06168776-20010102-C00028.png) 1959-06-22
US821943A US3048695A (en) 1959-06-22 1959-06-22 Copy method and apparatus
FR830647A FR1260420A (fr) 1959-06-22 1960-06-21 Procédé et appareil de copie perfectionnés

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Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3131080A (en) * 1960-11-09 1964-04-28 Robert B Russell Thermographic transfer sheet comprising selective radiation filtering means
US3148617A (en) * 1962-10-25 1964-09-15 Dick Co Ab Copy process
US3185087A (en) * 1960-09-22 1965-05-25 Columbia Ribbon & Carbon Thermographic duplicating process
US3214585A (en) * 1961-09-29 1965-10-26 Kalle Ag Thermotransfer copy apparatus wherein the reproduction coating is carried by a pressure roll
US3230875A (en) * 1963-01-16 1966-01-25 Columbia Ribbon & Carbon Thermographic duplication
US3316403A (en) * 1964-10-26 1967-04-25 Robert B Russell Thermographic copying apparatus with means to reverse the movement of a continuous transfer sheet
US3324292A (en) * 1964-10-26 1967-06-06 Robert B Russell Thermographic copying machine with a series of driven rollers to separate the copy and transfer sheets
US3336461A (en) * 1965-04-26 1967-08-15 Du Pont Machine for transferring thermoplastic images
US3902062A (en) * 1973-12-27 1975-08-26 Xerox Corp Reverse path imaging and transfixing copying method

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2503758A (en) * 1947-08-16 1950-04-11 Eastman Kodak Co Fusion photothermography
US2769391A (en) * 1951-11-14 1956-11-06 Dick Co Ab Method of manufacturing imaged hectograph spirit master
US2808777A (en) * 1952-02-26 1957-10-08 Dick Co Ab Method for manufacturing duplicating masters
US2844733A (en) * 1956-04-02 1958-07-22 Minnesota Mining & Mfg Reflex thermoprinting
US2880110A (en) * 1954-12-02 1959-03-31 Minnesota Mining & Mfg Heat-sensitive copying-paper
US2891165A (en) * 1955-03-28 1959-06-16 Minnesota Mining & Mfg Thermocopying machine
US2897090A (en) * 1957-04-11 1959-07-28 Anken Chemical & Film Corp Heat-sensitive copying paper
US2916622A (en) * 1956-12-28 1959-12-08 Kalvar Corp Methods and apparatus for copying

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2503758A (en) * 1947-08-16 1950-04-11 Eastman Kodak Co Fusion photothermography
US2769391A (en) * 1951-11-14 1956-11-06 Dick Co Ab Method of manufacturing imaged hectograph spirit master
US2808777A (en) * 1952-02-26 1957-10-08 Dick Co Ab Method for manufacturing duplicating masters
US2880110A (en) * 1954-12-02 1959-03-31 Minnesota Mining & Mfg Heat-sensitive copying-paper
US2891165A (en) * 1955-03-28 1959-06-16 Minnesota Mining & Mfg Thermocopying machine
US2844733A (en) * 1956-04-02 1958-07-22 Minnesota Mining & Mfg Reflex thermoprinting
US2916622A (en) * 1956-12-28 1959-12-08 Kalvar Corp Methods and apparatus for copying
US2897090A (en) * 1957-04-11 1959-07-28 Anken Chemical & Film Corp Heat-sensitive copying paper

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3185087A (en) * 1960-09-22 1965-05-25 Columbia Ribbon & Carbon Thermographic duplicating process
US3131080A (en) * 1960-11-09 1964-04-28 Robert B Russell Thermographic transfer sheet comprising selective radiation filtering means
US3214585A (en) * 1961-09-29 1965-10-26 Kalle Ag Thermotransfer copy apparatus wherein the reproduction coating is carried by a pressure roll
US3148617A (en) * 1962-10-25 1964-09-15 Dick Co Ab Copy process
US3230875A (en) * 1963-01-16 1966-01-25 Columbia Ribbon & Carbon Thermographic duplication
US3316403A (en) * 1964-10-26 1967-04-25 Robert B Russell Thermographic copying apparatus with means to reverse the movement of a continuous transfer sheet
US3324292A (en) * 1964-10-26 1967-06-06 Robert B Russell Thermographic copying machine with a series of driven rollers to separate the copy and transfer sheets
US3336461A (en) * 1965-04-26 1967-08-15 Du Pont Machine for transferring thermoplastic images
US3902062A (en) * 1973-12-27 1975-08-26 Xerox Corp Reverse path imaging and transfixing copying method

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NL252898A (US06168776-20010102-C00028.png)

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