US 3195455 A
Description (OCR text may contain errors)
y 0, 1965 D. A. NEWMAN 3,195,455
DUPLICATING PROCESS Filed July 29, 1965 MASTER SHEET HECTOGRAPHIC IMAG HE'AT MODIFIABLE SOLID COPY SHEET uvmvron Douylas 19. New/72am WMM ATTORAEYS United States Patent 3,195,455 DUPLHCATHNG PROCESS Douglas A. Newman, Glen Cove, N.Y., assignor to Columbia Ribbon and Carbon Manufacturing Co., The, Glen Cove, N.Y., a corporation of New York Filed Juiy 29, 1963, Ser. No. 300,120 6 Claims. (Cl. 101-14.5)
This application is a continuation-in-part of my copending application Serial No. 9,049, filed February 16, 1960, now abandoned, which in turn is a continuation-inpart of my application Serial No. 791,770, filed February 6, 1959, now abandoned. This invention relates to a process for the reproduction of multiple copies from an imaged hcctograph master and more particularly to the reproduction of such copies in a new and improved manner.
Heretofore hectograph copies have been made by reproduction processes which have been carried out by systerns generally referred to in the art as either the gelatin system or as the spirit duplicating system. These previous systems necessitating the wetting of the copy sheet were subject to a number of disadvantages such as the difficulty of stacking the wet and thereby softened copies which frequently curled and stuck together. In addition, the imprinted matter on the Wet copies frequently tended to blend and back print. Among other disadvantages were the ditficulties of controlling the amount and distribution of the dye solvent and the inconvenience due to the odor and physiological effects accompanying its evaporation during the duplicating process.
In order to avoid the disadvantages of such wet hectograph processes it has been proposed to use a dry method in which an imaged hectograph master sheet is pressed against copy sheets having thereon a dry coating containing an amount of solvent for the dyestutf in the master images. Under the effect of the pressure a portion of the master images is transferred to the copy sheet in the form of faintly colored images which increase in strength as the dyestuff is dissolved by the solvent of the copy sheet coating.
While such a dry process does overcome the disadvantages of the wet process it has not met with much success due to at least two important limitations thereof. The first and most important limitation results from the fact that the process involves the pressure transfer of a portion of the master images to the copy sheet so that the copy sheet itself becomes somewhat of a master. The transferred portion of the master images contains more dyestuif than is necessary to form color in just the image areas and unless such dyestutf is insolubilized by the inclusion of a dye precipitant the excess dyestuff will dissolve into adjacent areas of the copy sheet coating so that the image areas will spread and become blurred. Such dye precipitant has the disadvantage that it may precipitate the dyestuit before the dyestutf has been sufficiently well dissolved into the copy sheet coating to form the desired colored images. Even when the dyestuif is insolubilized it is present as a mass deposit on the copy sheet coating and tends to spread and stain on contact with the hands. Another limitation of such process resides in the slow color development which requires that the duplicating process be interrupted until it is ascertained whether the particular master sheet being used will eventually produce copies of the desired intensity.
It is an object of this invention to provide for the imaging of copy sheets by a hectograph dye-imaged master sheet through the use of heat together with a minimal amount of pressure to effect contact and in the absence of the usual spirit duplicating fluids.
It is another object of this invention to provide a dry method for producing true hectograph copies directly from a master sheet, the formed images consisting of stains of dyestuff dissolved from the master images onto the copy sheet in the form of stable images of immediate intensity.
It is still another object of this invention to provide a dry hectograph duplicating method which avoids the transfer of any undissolved dyestulf to the copy sheet.
It is a still further object of the present invention to provide for the continuous imaging of a continuous copy sheet and in the absence of combustible volatile solvents.
These and other objects are accomplished in the manners hereinafter described.
Other features and advantages will hereinafter appear.
In the drawing:
FIGURE 1 is a fragmentary sectional view showing in detail a master sheet and a copy sheet embodying the principles of this invention, shown out of contact for purposes of clarifying the illustration.
FIG. 2 is a sectional view showing an arrangement of a master carrying drum, a copy sheet preheater and a heated pressure roll included in an apparatus suitable for carrying out the process used herein for duplicating and transferring hectograph images from a master sheet to successive copy sheets.
FIG. 3 is a sectional view of an arrangement of a master carrying drum and copy sheet preheater in a simplified apparatus for carrying out the process of this invention.
FIG. 4 is a sectional view of an arrangement of a continuous master sheet and a continuous copy sheet according to the present invention.
As shown by FIG. 1 of the drawing, a master sheet 10 is provided with images 11 thereon of soluble material capable of producing color on a copy sheet. A copy sheet 13 is provided with a superficial film 12 of heatmeltable solid developer impregnated on the surface thereof.
In the device and process used for copying or duplicating the printed matter from the master sheet shown diagrammatically in FIG. 2, master sheet 10 is shown carried by a drum 21 and in pressure contact with a copy sheet 13 with the coated side 12 of the copy sheet facing and in contact with the imaged surface, i.e. bearing image 11, of the master sheet. The copy sheet is preheated by hot plate 15 and then advanced between the drum 21 and the roller 22. If desired, a bank of infrared heating lamps 16 may be used to preheat the copy sheet. Roller 22 is heated by any suitable means 23, such as an electrical coil or the like, in order to maintain the coating on the copy sheet at a determinate temperature suitable for layer 12 to dissolve off dye from the imaged master. Although heat is applied constantly to the roller 22, it is to be noted that heat does not accummulate on the master sheet ill or drum 21 carrying the master sheet and thereby melt or otherwise impair the image or images carried by the master sheet. This application of heat and pressure over a very short interval of time enables the copy sheet to make a complete copy.
The pressure contacting rollers diagrammatically shown in FIG. 2 illustrate one device for carrying out the process of this invention. Electrical heating means 23 are provided to maintain a temperature of F. to 200 F. or any such temperature as may be necessary to render the dye-dissolving coating 12 sufiiciently fluid to effect the dye-dissolving transfer step in this process. It is to be noted that the temperature necessary to melt the dyedissolving solid on the copy sheet is of such intensity as not to simultaneously impair or endanger the image on the master.
The embodiment illustrated in FIG. 3 provides a master sheet carried by drum 21 and held in pressure contact with a copy sheet 13 by spring biased felt pad 17. Copysheet 10. Thecopy sheet is preheated to the determinate temperature by infrared lamp 16.
The embodimenti-llustrated in FIG. 4 provides a continuous master sheet 10 which carries imagingmaterial 11 in preselected areas, and a continuous copy sheet 13 which has its coated side 12 facing .the imaged surface of the master sheet. The copy sheet is preheated to the determinate temperature by infrared lamps loyafter it leaves roller 41. It then comes in pressure contact at rollers 20 and 21 with the master sheet which is unwound from roller 31. The master sheet is then wound "on roller 32 for further use while the imaged copy sheet is wound on roller 42. i
The present invention involves the use of a copy paper free of imaging pigment or dyestufi comprising a paper sheet coated on its printing side with a heatamel-table solid which when heated softens and becomes fluidand is thus converted into a state in which it is a solvent for the dye used in the image on th'e'ma-ster. of fusible solids such as the solid fatty alcohols, fatty a'c'ids'or esters or mixtures thereof may be employed for the coating on the copy paper, the essential requirement Any one of a number.
melting coatings tend to tackify at room temperature causing sticking of the stored copy sheets, while coatings having melting temperatures much inexcess of about 150 F. are exceedingly hard and resist melting and prevent V imaging of the copy sheets.
melting Wax which in itself is not a solvent for the dye in the master image but which wax includes admixed therewith a substantial'amount of a dye solvent may be used as such a copy sheet coating. 'Then when the copy being that when they are heat-activated they are solvents for the imaging material on the master sheet. Examples of materials which may be used are solid alcohols such as cetyl, myristyl and stearyl; solid fatty acids such as stearic,
palmitic, lauric and capric solid esters of various glycols,
and of organic acids and solid glycol'ethers such as the polyethyleneand polypropylene-glycol ethers. By the term coating as used herein is preferred a superficial film of heat-meltable solid material, the major part of which impregnates the paper foundation and is held below the surface thereof. Such coating is applied in an amount just sutficient to wet the surface ofthe copy sheets'and insufficient to result in the formation of asep-arate frangi ble layer on the, surface of the sheet. Itiis important to the present process that the coating on the copy sheets be-non-transferable to the master sheet under the effects f of heat or pressure in that such transfer would frustrate any attempt to image the copy sheets and would also result in contamination and destruction of the master sheet.
The non-transferability of the coatings of the present invention is'eifected by controlling the amount of heatrneltable solid material'which is applied to the paper foun- V ness depends upon the type-and quality of t-he'paper and whether it is sized or otherwise treated. If one wishes to apply a pressure-transfer layer toa paper foundation, it is well-recognized that a certain amount of the transfer material is lost or wasted due to impregnation by the paper sheet and saturation of the surface rough spots and interstices. Such impregnation and saturation is ne ces- .sary to provide tooth for the transfer coating but, however, the amount of material used up for these purposes is firmly held by the foundationshe'et and is not. transferable under pressure. Only that amount of the coating, beyond that held by interfacial attraction, is pressuretransferable. V r
' It is also important that the coating on the copysheets softens and melts at a temperature within the range of approximately 90 to about 150 R, which' is the preferred temperature range of1the present process. Tower to a solid transfer;
sheet and the filmf orming the coating are heated above atmospheric or room temperature, the composition softens. Said composition in itsfsoftenedand modified state will then be effective to dissolve sufficient dye from the imaged master toform a legible copy:
. a When the image .transfer is tobe effected, the normally and comparatively solid (at roomtemperature) coating onthe copy sheet is melted by hot plate 15 or infrared lamp bank 16 and the modified coating becomes a solvent for the dye present in the image :on the master sheet. Then by subjecting the copy sheet and its immediately contiguous imaged master sheet to a sufiicierit P pres-sure to maintain intimate contact therebetween, the "contact of the normally solid but now melted dye solvent on the copying'surface of the copy sheet with the image on the hect-ograph imaged surfaceof the master sheet dissolves someof the dye from the image and transfers the dissolved dyestulf from the master sheet onto the copy sheet surface to reproduce'the desiredcopy in the form of stabl'e,.sharp images of immediate intensity. The
image on the master being in mirror reverse, a directly reading copy is obtained on the copy sheet.
As can be seen from the foregoing, the present, process, while termed a dry process, actually functions in much the same manner as the wet hectograph process while avoidingthe disadvantages thereof. Thus, in either case, the master sheet is contacted with acopy sheet on which the surface is wette'd with liquid dye solvent. Only dissolved dyestufi? is transferred to the copy sheet since only minimal contact pressure isexerted and since the surface of the copy sheet is fluid and thus not receptive The dyestuif which transfers to the copy sheet is completely dissolved so'that the images formed on the copy sheet are of immediate intensity and are stable since there is no excess of undissolved dyestuff which can be dissolved from the images :into adjacent areas of the .copy sheet. The duplicate images on the copy sheet areide'ntical to corres'pondingimages formed inthe wet or spirit process since they are mere dye stains having no excess mass which might tend to spreador stain on contact with the'hands.
The heating of the copy sheet may take place immediately before the copy sheet makes contact. with the mastersheet, as exemplified .for instance by FIG. 4 of the drawing, or preferably the heating may take place while the copy and master sheets are in contact, as exemplified F by FIG; 2 of the drawing. .A convenientfmethod of heating the sheets together is to pass them through a suitable infrared radiationmachine such as apThermoe Fax machine or "the like. The ambient temperature generated ,by the machineis "su'flicient to melt. the dye developer on the copy sheet and-dissolve some of the dye from the master sheet to image the copy sheet. If desired an amount of radiation-absorbing pigment may be included in the'copy sheet coating or foundationto create additional heat and speed the process.
According to'another embodiment of the present invention, conventional complementary chemical color formers are employed in place of hectograph dyestutfs- For instance, the, image on the master sheet contains one color-formmg chemical such as an organic acid, such "as gallic or tannic acid; a thiocyanatederivative such as thiocyanate or tolyl thiocyanate; or a sodium, potassium or ammonium salt of ferrocyanide or ferricyanide, etc., While the heat-fusible copy sheet contains the corresponding chemical which when brought into liquid contact with the chemical of the master sheet reacts therewith to form a sharp colored image on the copy sheet. The corresponding chemical on the copy sheets may be an iron salt such as ferric chloride, ferric ammonium sulfate or iron benzoate, etc.; a copper salt such as cupric chloride, copper acetate or cupric potassium sulfate, etc.; and the corresponding salts of manganese, lead, silver, mercury, nickel and others well known to the art. In this embodiment, the heat-fusible solid material on the copy sheets liquefies under heat and appears to function in a twofold manner. In the first place, it dissolves and absorbs some of the chemical from the images on the master sheet; secondly, it serves as a liquid reaction medium for the complementary chemical reagents, namely the chemical originally present on the copy sheets and the chemical dissolved and absorbed from the master sheet, thereby causing the chemicals to react and form a sharp colored copy corresponding to the imaged areas of the master sheet. To aid in the reaction, it is preferred to have a humectant present on the copy sheets, which absorbs humidity and renders the chemicals more completely ionically available for reaction. Materials such as ethylene glycol and the carbowaxes function particularly well as humectants.
The melted coating almost immediately after forming the duplicate copy from the master sheet solidifies or returns to its normally and comparatively solid state and readily separates from its contiguous master.
In preparing the copy sheets of this invention, one of the preferred coatings of the heat-modifiable or meltable kind for the copy sheets has a plasticizing agent included therein. Such a coating when subjected to heat causes the solvent to ooze out over the coated surface. A specific example of such a coating mixture would be made up of equal parts by weight of dibutyl phthalate and cetyl alcohol coated on the surface or impregnated into the copy sheet web. When subjected to heat as by hot plate 15, the solvent migrates to the surface and when contacted with the imaged master produces an immediately legible copy.
When it is desired to produce continuous copy sheets from a continuous or repeating master sheet, any conventional apparatus which functions in the manner emplified by FIG. 4 may be employed. A continuous strip or wide web of master sheet is carried on roller 31 and a continuous strip or wide web of copy sheet, corresponding in width with the master sheet, is carried on roller 32. Both sheets are brought into pressure contact at rollers 20 and 21, the pressure being in general only that amount required to hold the sheets in intimate contact with one another. Heating of the copy sheet may occur before the sheets are brought in contact, as shown by FIG. 4, or at the time of contact by supplying roller 20 with heating means such as electrical heating means 23 exemplified by FIG. 2 herein.
The copy sheet of this invention may be made by several diverse methods. For example, the normally solid and heat-meltable solvent may be melted and coated on the Web of paper from which the copy sheets are made by hot rolling methods. Alternatively, some of the normally solid and heat-meltable solvent materials, such as the solid alcohols, may be dissolved in suitable volatile solvents and applied to the copy paper by any one of a number of conventional coating methods such as hot melt, emulsion coatings, spraying solvent coatings, dusting and fusing coatings, or other means. Thus, for example, by blending granules of the normally solid meltable solvent and dispersing the resultant fine granular materials in a water emulsion and coating the emulsion onto the copy paper, evaporation of the aqueous vehicle 0 leaves a coating suitable for carrying out the process of this invention. The amount of coating applied is generally quite small and only sufiicient to wet the surface of the copy sheets. Upon setting or drying, the coating is nearly entirely absorbed by the copy sheets which become impregnated in this manner. The use of an excess amount of coating material is to be avoided in that it remains on the copy sheet surface as a frangible, transferable layer which tends to become mushy during use and contaminate the master sheet.
A number of coating compositions embodying heatmoclifiable or meltable materials may be coated onto the copy sheet 13. These coatings are such as fuse, otherwise modify or may even become liquid when subjected to the increased temperature of the process of this invention and in this modified or fused, or even liquid state, have the necessary dye or chemical solvency to reproduce record data on the surface of copy sheets which are heated by hot plates or infrared lamps and brought into contact with a dye or chemically imaged master.
The following examples of coatin mixtures suitable for use on the copy sheet are merely illustrative and not to be understood as limitative embodiments:
EXAMPLE I (l'vlolten state coating) Parts by Weight Stearic acid 75.0 Cetyl alcohol 25.0
100.0 EXAMPLE II (Molten state coating) Parts by weight Carbowax 4000 (solid polyethylene glycol polymer having an average molecular weight between 300 and 3700) 30.0 Colloidal clay 30.0
100.0 EXAMPLE III (Water dispersible binder) Parts by Weight Water 100.0
Carbomethyl cellulose (medium viscosity) 3.0 Carbowax 4000 10.0
EXAMPLE IV (Emulsion type) Stearic acid 12.0 Gleic acid 12.0 Triethanolamine 1.2 Hot water 165.0
EXAMPLE V (Solvent type) Parts by weight Rosin (wood rosin) 12.0 Tricresyl phosphate 3.0 Ethyl acetate 80.0 Colloidal clay 5.0
Colloidal clay 20.0 Copper sulfate 30.0
From the above examples, it is 'to be noted that several types of coatings can be used to produce the copy sheets. In Examples I, II and VI above, the fusible material itself is hot roll coated or knife coated and absorbed in the molten state by the surface of a web of paper from which the copy sheets are formed. In still another example, a suitable meltable solid dissolved in a volatile solvent is coated on the copy sheet and evaporation of the volatile solvent results in a heat-meltable film containing the solvent for the chemical or dye being absorbed by the copy sheet.
and comprising a non-volatilesolid which is meltable at a temperature Within the range of about 90 F. to 150 F. and which, only in its heat-melted state, is a solvent for the solid soluble imaging material of the master sheet images,said superficial coating in its melted state being ,unreceptiveto the transfer of said solid soluble imaging material in its solid state; heating said superficial coating to a temperature within the range of about 90 F. to about 150F. to melt the said coating and the said non-volatile solid and contacting the melted coating with the images on the master sheet whereby a portion of the solubleimaging material is dissolved by the melted non-volatile solid into the melted coating while the undissolved portion of the imaging material remains on the master sheet; and separating the copy sheet from the master sheet whereby duplicate, smudge-resistant and stable imagesof immediate intensity are formed in the coating on the copy sheet In Examples III and IV, the solid material is held as dispersed particles in a fluid film former such as casein, carboxymethyl cellulose, starch, polyvinyl alcohol or any water-dispersible colloid such as is commonly used in the paper industry. In the latter case, the solid material is preferably present in discrete particulate form, the par:
ticles of which fuse and melt together when subjected to copy sheet.' It should be understood that any of the aforementioned copy sheet complementary chemical reagents may be substituted in place thereof, preferably in an amount ranging from about 20-40% byweight, based upon the total weight of the coating composition.
Variations and modifications may be made within the scope of the claims and portions of the improvements may be used without others. 7
I claim: v
1. In the dry method of imaging dry, coated hectograph. copy sheets directly from an imaged hectograph'master' sheet on which the images contain solid soluble imaging material capable of being dissolved into the coating of the copy sheet to form brightly colored images thereon, the improvement which comprises usinga copy sheet having a solid non-transferable superficial coating meltable at a temperature within the range of about to F.
. the master sheet.
in areas corresponding to the location of the images on 2. The method according to claim 1 in which the/imaging material on the master sheet comprises hectograph dyestuff. v V j 3. The method according to claim 1 in which the imaging material on the master sheet comprises a' chemical compound and the coating on the copy sheet includes a different chemical compound which when placed incontact'with the chemical compound dissolved from the masterisheet reacts therewith to produce a brightly colored.
reaction product contrasting with the color of either of the chemical compounds used.
4. The method according to claim 1 in which the nonvolatile solid in the copy sheet coating comprises a solid alcohol. i 7
. 5. The method according to claim 1 in which the step of heating the superficial coating is carried out while, the coating is in contactwith the images on the master sheet.
6. The method according to claim] in which the step of heating the superficial coating is carried out immediately before the coating is contacted with the images on the master sheet.
References Cited by the Examiner UNITED STATES PATENTS 2,501,495 13/50 Carroll etal. 101149.4 X
2,503,758 4/50 Murray. 2,769,391 11/56 R0sl1kind 101-149.4 2,954,311 9/60 Vander Wee1; 101 149.4 .2,'957,411 310/60 'Black 101-1495 3,034,428. 5/62 Ellam .101-,-149.5 3,076,4G6 2/63 7 Florence POI-149.5
' DAVID KLEIN, Primary Examiner.
WILLIAM B. PENN, Examiner.