US2872863A - Hectograph duplicating - Google Patents

Description

United States tent HECTIQGRARH DUPLICATING Douglas A. Newman and Harrison W. Boylan, Glen Cove, Allan T. Schiotzhauer, Locust Valley, and Stephen 3. Smatlalr, Hicltsviile, N. 2 1, assignors to Columbia Ribban and Carbon Manufacturing Company, Inc., Glen Cove, N. Y., a corporation of New York No Drawing. Application December 2, 1954 Serial No. 472,772

7 Claims. (til. ibi 1494) herein is intended to include all manifolding processes in which a medium having an image in the form of a color-producing material suspended in a suitable base is brought together with successive copy sheets in the presence of an activating or developing agent for the materials to reproduce the image on the copy sheet.

Heretofore, in making copies by the hectograph dupli cating process, the master sheet was commonly imaged with a dye usually crystal violet, soluble in Water or spirits, the image being reproduced on copy sheets by contacting the latter with the image dyestuffs in the presence of a solvent therefor, such as water and/or alcohol. The copies thus produced are somewhat limited in their permanency because the dyestuffs of the class which are satisfactory in carrying out the above method, are not very stable in the presence of light and tend to fade and bleach out with age.

' Further objections stem from use of the dyestuffs which are highly water-soluble and therefor, readily transfer to other damp objects during handling resulting in stains, particularly to the hands of the user, Which require a special cleansing fluid for removal.

It has also been proposed to avoid the above difficulties by breaking the basic soluble dyestuffs into separate base dye components which have substantially no color transfer value when they are separately applied to the master. sheet and copy sheets respectively, but which will produce a colored image when the two dye com ponents are coupled into their basic dyestuffs in the presence of an activating or coupling agent included in an alkaline solvent used to wet the master or copy sheet. Even though the proposed method produces visible colored images and eliminates to some extent the objectionable dye color transfer during handling, it is not as economical as the conventional hectograph method using basic soluble dyestuffs. The proposed process requires, in addition to a complex method for breaking down the basic dyestuffs into their basic components, a modification of the duplicating machine to resist the alkaline reaction or" the solvent on the parts of the machine.

it is an object of this invention to produce duplicate copies by the ,hectograph process utilizing the conventional duplicating machines now commonly in use and avail-able, without any modifications thereof, by using materials which do not have the objections encountered heretofore, and which will produce a permanent visible colored image on the copy which will not perceptibly fade or bleach even though exposed to ordinary incident light for long periods of time.

it has been found that this may be accompl shed by using complementary chemical reagents of the class including metallic salts as one reagent and an organic acid as the other reagent which by themselves are substan- Fat enteol Feb. 1%, lit-5 Cilia? 2 tially colorless but when combined in the, presence of moisture will develop a visible colored image.

In carrying out the invention the; complementary reagents are kept segregated, preferably one being applied in or on the copy sheet and the other to the master sheet in image form, and they are combined only when the copy sheet is placed in contact with an imaged master in the presence of a solvent for the imaging material to transfer a portion of the latter in image form from the master to the copy sheet. The moisture necessary to complete th reaction and produce colormay be ob tained from any suitable source, as for instance, moisture in or on the copy paper, and/or from the solvent used to dissolve the image reagent.

There are numerous metallic salts andcomplementary organic acids which, in the presence of moisture, produce permanent duplicate copies when used in accordance with the method of this invention, the choice of the re? agents used in the process being determined by the color of the image desired on the copies. For example, if a blue-black is desired either ferric sulfate or ferric chloride may be used with their complementary reagent gallic acid, or if red is desired, nickel and glyoxime may be used.

The chemical reagent may be imaged on the master sheet in a conventional manner by the use of a transfer member such as a sheet or ribbon having onits Working surface a transferable layer which includes the chemical reagent. In the preferred form of the invention the organic acid such as gallic or tannic acid is used on the transfer member because of its ready solubility in alcohol which is the wetting fluid commonly used in the, duplicating process. pared by suspending the acid reagent, as for instance, the gallic acid, in either its fluid or. solid form in any of the conventional bases such as wax or substitutes therefor which when applied as a coating on a flexible foundation will form a releasably adhering layer and transfer in image form when subjected to an imaging force. 3

A transfer coating composition which has been found satisfactoryis formulated as follows:

Although the ingredients in the, composition as set forth above may all be converted to their dissolved state and so applied to a transfer sheet, in the preferred form all of the ingredients with the exception of the gallic acid are melted together and thereafter ground particles of the gallic acid are added. The composition prepared in either of the above ways is thereafter applied in any conventional manner, as for exam-pie, by brush coating, on a paper or other flexible foundation to form the transfer member, and the latter may bein ribbon, sheets, or continuous strip form.

The transfer member is positioned with its coated side in surface contact with the image-receiving surface of a master sheet and subjected to an imaging force by an inscri-bing instrument, such as a stylus or type, whereby portions of the layer in image form transfer from the transfer member and adhere tothe master sheet. The transfer nieinber master sheets imaged thereby can be handled Without the danger of staining the person or The transfer layer may be pro:

clothing of a user since the material used is colorless and does not have any color transfer value.

The copy sheets in the preferred form of this invention are provided with the chemical reagent, i. e. the metal salt, which is complementary to that which is imaged upon the master sheet and which will in contact therewith in the presence of moisture produce color as a visible image. In the preferred form of the invention the metallic salt, as for example, ferric chloride, is included in a coating applied to the copy paper.

The coating materials forming the base for the complementary metallic salt should be of the type which is fairly resistant to dissolving in the fountain fluid in order to prevent transfer of the metallic salt contained therein to the imaged master sheet during the taking of copies therefrom so that the reaction and color formation will not occur on the master sheet but only on the copy sheet as desired. The copy paper and imaged master sheets are contacted in the presence of the fountain fluid containing the solvent for the imaging materials, the organic acid, for instance. The fountain fluid should be a solvent for the imaging materials on the master sheet and rapidly dissolve and transfer a portion of the latter to the copy sheets, but the fountain fluid should not be a solvent with respect to the copy sheet coating materials whereby the latter does not dissolve and release metallic salt contained therein for reaction with the imaging materials during the brief instant that the copy paper and master sheet are in contact.

The retention of the metallic salt in the coating on the copy paper is accomplished in the present in Vendor; by including in the coating cellulosic film-forming materials such as, for example, cellulose acetate, which are resistant to dissolving in the alcohol normally used in the fountain fluid. Under some circumstances, when the film-forming coating is not sufliciently porous to permit the desired extent of ingress of the imaging materi1l into the coating, a component may be included in the fountain fluid along with the solvent for the imaging material as a solvent for the coating materials which will partially break down the surface thereof to permit the combiuing of the imaging material and the chemical reagent in the coating.

As previously pointed out, the presence of moisture is essential for the reaction, between the metallic salt and the organic acid to occur and develop a visible image on the copy sheet. It is desirable that the moisture content present duringthe duplicating process be suflicient to produce a strong, instantaneously visible image on the copy sheet. While all the moisture required may be included in the fountain fluid to Wet the copy paper during the duplicating process, this is generally not preferable because it causes excess wetting and an undesirable limpness in the copy paper resulting in diflicult feeding of the paper in the hectograph duplicating machine. It is therefore preferable that the fountain fluid contain a minimum amount of moisture.

By the present invention it has been discovered that the moisture in the fountain fluid may be maintained at a minimum by providing the copy papers with the additional moisture needed for producing a satisfactory instantaneous copy. This is accomplished by giving hygroscop1c properties to the copy sheet by providing glycerine thereon. In order that the overall reaction on the copy paper produce instantaneous and simultaneous images of strong uniform intensity over the entire area of the copy sheet, it is desirable that the coating on the copy paper have a uniform moisture content over its entire surface. This is accomplished by using hygroscopic materials as for example, glycerinc, in a coating compositron including polyethylene glycols, as for example, Carbowax, manufactured by the Carbide and Carbon Chemical Corp., whereby the moisture will be uniformly dispersed throughout the coating. In the present preferred form of the invention, the hygroscopic material cop j sheet.

is included in the film-forming coating having the chemical reagent dispersed therein.

A typical coating composition which has been found satisfactory is formulated as follows:

Ingredient: Percent by weight Ferric chloride 1.5

Glycerine 4.7 Carbowax 1500 (Carbide and Carbon Chemical Corp.) 7.l Cellulose acetate (acidic content 53-54%) 4.7 Ethyl acetate 82.0

The above composition is applied as a coating to the copy medium by solvent methods, and may also be in corporated on the paper during its manufacture.

The coating composition may include such inert ma terials as clay and the like to improve the coating properties and prevent leaching of the reagent through the copy paper.

To reproduce copies with the master and copy sheets as prepared in the above manner by the hectograph spirit duplicating method, the copy sheets are wettcd by the fountain solution which will not react with the chemical reagents on either the master or copy sheet to produce color thereon. When the gallic acid is imaged on the master sheet, a solvent such as alcohol may be used in the fountain fluid. Tne copy sheet is then contacted wi.h the imaged portion of the master sheet to dissolve a portion of the imaged reagent which adheres to the An instantaneous development of the image then. occurs on the copy sheet due to the presence of moisture supplied from the coating on the copy sheet and from the fountain fluid. If an iron salt such as ferric chloride is used as one reagent to react with gallic acid, a blue-black image will be reproduced which with age will become blacker.

A fountain solution which has been found satisfactory is formulated as follows:

Ingredient: Percent by volume Methanol 38.2 Ethanol 48.2 Cellosolve (2-ethoxy ethanol) 4.5 Water 9.1

The above method in addition to providing permanent copies will also produce copies of equal intensity throughout a long run of successive copy sheets before the imaging reagent has become exhausted. This is not possible with methods commonly used heretofore, because the dyestuff was gradually diluted after successive copies, producing weaker copies toward the end of the run, while according to the present invention the imaging is dependent upon a development reaction which will always rcproduce copies of equal intensity until it is consumed.

Variations and modifications may be made Within the scope of the claims and portions of the improvements may be used without others.

We claim:

1. The method of producing duplicate copies by the hectograph process using on a master sheet and copy sheets complementary chemical reagents which when combined in the presence of moisture develop a color; comprising the steps of coating a transfer sheet with a transferable coating composition having gallic acid dispersed therein; superposing said transfer sheet with a master sheet in face-to-face contact with said transfer coating on said transfer sheet; subjecting said superposed sheets to an imaging force to release from said transferable coating imaged portions and adhere them on said master sheet; dispersing iron salts and glycerinc in a coating composition including cellulose acetate; coating at least one surface of said copy paper with said composition containing said metallic salt; wetting said copy paper with a solution including a solvent for the gallic acid and moisture insufficient to cause litnpness in said copy paper; contacting said imaged master sheet and a coated copy paper to transfer and adhere a portion of said transfer coating including said gallic acid in image form on said copy paper whereby when said copy paper and master sheet are out of contact a visible image will instantaneously develop on said copy paper due to the presence of the moisture from said wetting solution and that provided by the glycerine on said copy paper.

2. The method as defined in claim 1 in which the coat ing composition applied to the copy sheets includes the following ingredients in substantially the proportions given:

Ingredient: Percent by weight Ferric chloride 1.5 Glycerine 4.7 Polyethylene glycols 7.1 Cellulose acetate 4.7

Ethyl acetate 82.0

3. The method as defined in claim 1 in which the transferable coating composition on the transfer sheet includes the following ingredients substantially in the proportions given:

Ingredient: Percent by weight Carnauba wax 8.5 Raw montan 2.5 Pure beeswax 2.5 Lanolin 10.2 Mineral oil 13.6 Gallic acid 50.8 Cetyl alcohol 8.5 Titanium dioxide 3.4

4. A copy paper for use in duplicating by the hectograph process using a master sheet imaged with gallic acid, comprising a flexible foundation having a coating on one surface thereof comprising a film-former of cel- .lulose acetate; and hygroscopic materials including glycerine and ferric chloride uniformly dispersed therein whereby when said copy sheets are contacted with said master sheets and portions of the image transferred thereto, the gallic acid will react on the copy sheets to develop visible images thereon.

5. The invention as defined in claim 4 in which the coating on the one surface of said copy sheet comprises the following ingredients substantially in the proportions given:

6 Ingredient: Percent by weight Ferric chloride 8.35

Glycerine 26.1

Polyethylene glycols 39.45 Cellulose acetate 26.1

6. The method of producing duplicate copies by the hectograph process using on a master and copy sheets complementary chemical reagents including metallic salts as one reagent and gallic or tannic acid as the complementary reagent which when combined in the presence of moisture develop visible images, comprising the steps of imaging said master sheet with one of said chemical reagents, providing on at least one surface of said copy sheets a humectant in addition to a dispersion of the chemical reagent complementary to said first reagent, contacting the imaged portions of the master sheet with a copy sheet in the presence of a solvent for the imaged reagent to transfer and adhere portions of the latter in image form to said copy sheet whereby the chemical reagents thereon Will react in the presence of moisture including that provided by the presence of said humectant to develop visible images on the copy sheet, in which the complementary reagent is applied .to the copy sheets by coating the surface of the latter with said complementary reagent, and in which the complementary reagent is dispersed with a film-former which in solidified form is resistant to solution in the solvent for the imaged reagent before the copy sheets are contacted therewith, and in which the film-former comprises cellulose acetate.

7. The method as defined in claim 6 in which said copy sheet prior to contacting it with the imaged master sheet is wetted with a solution comprising methanol, ethanol,

Z-ethoxy ethanol and water.

References Cited in the file of this patent UNITED STATES PATENTS 1,950,982 Gookin et al Mar. 13, 1934 2,146,976 Neidich Feb. 14, 1939 2,168,098 Groak Aug. 1, 1939 2,217,349 Neidich Oct. 8, 1940 2,634,677 Klimkowski et al Apr. 14, 1953 2,663,657 Miller et a1. Dec. 22, 1953

Claims (1)

1. THE METHOD OF PRODUCING DUPLICATE COPIES BY THE HECTOGRAPH PROCESS USING ON A MASTER SHEET AND COPY SHEETS COMPLEMENTARY CHEMICAL REAGENTS WHICH WHEN COMBINED IN THE PRESENCE OF MOISTURE DEVELOP A COLOR; COMPRISING THE STEPS OF COATING A TRANSFER SHEET WITH A TRANSFERABLE COATING COMPOSITION HAVING GALLIC ACID DISPERSED THEREIN; SUPERPOSING SAID TRANSFER SHEET WITH A MASTER SHEET IN FACE-TO-FACE CONTACT WITH SAID TRANSFER COATING ON SAID TRANSFER SHEET; SUBJECTING SAID SUPERPOSED SHEETS TO AN IMAGING FORCE TO RELEASE FROM SAID TRANSFERABLE COATING IMAGED PORTIONS AND ADHERE THEM ON SAID MASTER SHEET; DISPERSING IRON SALTS AND GLYCERINE IN A COATING COMPOSITION INCLUDING CELLULOSE ACETATE; COATING AT LEAST ONE SURFACE OF SAID COPY PAPER WITH SAID COMPOSITION CONTAINING SAID METTALIC SALT; WETTING SAID COPY PAPER WITH A SOLUTION INCLUDING A SOLVENT FOR THE GALLIC ACID AND MOISTURE INSUFFICIENT TO CAUSE LIMPNESS IN SAID COPY PAPER; CONTACTING SAID IMAGED MASTER SHEET AND A COATED COPY PAPER TO TRANSFER AND ADHERE A PORTION OF SAID TRANSFER COATING INCLUDING SAID GALLIC ACID IN IMAGE FORM ON SAID COPY PAPER WHEREBY WHEN SAID COPY PAPER AND MASTER SHEET ARE OUT OF CONTACT A VISIBLE IMAGE WILL INSTANTANEOUSLY DEVELOP ON SAID COPY PAPER DUE TO THE PRESENCE OF THE MOISTURE FROM SAID WETTING SOLUTION AND THE PROVIDED BY THE GLYCERINE ON SAID COPY PAPER