Classifications

• • 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
  • B41M5/025—Duplicating or marking methods; Sheet materials for use therein by transferring ink from the master sheet
  • B41M5/0253—Duplicating or marking methods; Sheet materials for use therein by transferring ink from the master sheet using a chemical colour-forming ink, e.g. chemical hectography
• • 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
  • B41L11/00—Apparatus for directly duplicating from hectographic masters in mirror image, i.e. "wet duplicators" for producing positive copies
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10S—TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10S101/00—Printing
  • Y10S101/29—Printing involving a color-forming phenomenon

Definitions

• 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.
• a solvent therefor such as water and/or alcohol.
• 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 color may 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.
• 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.
• a transfer member such as a sheet or ribbon having onits Working surface a transferable layer which includes the chemical reagent.
• 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.
• 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.
• a transfer coating composition which has been found satisfactoryis formulated as follows:
• 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.
• an inscri-bing instrument such as a stylus or type
• 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.
• 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.
• cellulosic film-forming materials such as, for example, cellulose acetate, which are resistant to dissolving in the alcohol normally used in the fountain fluid.
• 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.
• 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.
• 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.
• the coating on the copy paper it is desirable that the coating on the copy paper have a uniform moisture content over its entire surface.
• hygroscopic materials as for example, glycerinc
• 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.
• the hygroscopic material cop j sheet In the present preferred form of the invention, the hygroscopic material cop j sheet.
• a typical coating composition which has been found satisfactory is formulated as follows:
• 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.
• 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.
• 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:
• 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
• 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.

Landscapes

• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Color Printing (AREA)
• Printing Plates And Materials Therefor (AREA)
• Cosmetics (AREA)
• Thermal Transfer Or Thermal Recording In General (AREA)

Priority Applications (6)

Applications Claiming Priority (1)

Publications (1)

Family

ID=23876879

Family Applications (1)

Country Status (6)

Cited By (8)

Citations (6)

Family Cites Families (1)

• 1954
  • 1954-12-02 US US472772A patent/US2872863A/en not_active Expired - Lifetime
• 1957
  • 1957-04-01 GB GB6844/57A patent/GB867507A/en not_active Expired
  • 1957-06-13 DE DEC14990A patent/DE1138076B/de active Pending
  • 1957-06-18 FR FR1180702D patent/FR1180702A/fr not_active Expired
  • 1957-06-21 CH CH4751357A patent/CH377860A/fr unknown
  • 1957-06-21 BE BE558590D patent/BE558590A/xx unknown

Patent Citations (6)

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