US3402109A - Electrolytic recording medium - Google Patents

Electrolytic recording medium Download PDF

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Publication number
US3402109A
US3402109A US600893A US60089366A US3402109A US 3402109 A US3402109 A US 3402109A US 600893 A US600893 A US 600893A US 60089366 A US60089366 A US 60089366A US 3402109 A US3402109 A US 3402109A
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US
United States
Prior art keywords
paper
recording medium
sheet
silver
electrolytic
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
US600893A
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English (en)
Inventor
Jay R Berman
Lieblich Irving
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.)
Hogan Faximile Corp
Original Assignee
Hogan Faximile Corp
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
Application filed by Hogan Faximile Corp filed Critical Hogan Faximile Corp
Priority to US600893A priority Critical patent/US3402109A/en
Priority to GB44178/67A priority patent/GB1148132A/en
Priority to DE1696215A priority patent/DE1696215B2/de
Application granted granted Critical
Publication of US3402109A publication Critical patent/US3402109A/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
    • B41M5/20—Duplicating or marking methods; Sheet materials for use therein using electric current
    • B41M5/205—Duplicating or marking methods; Sheet materials for use therein using electric current and an eroding electrode
    • 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
    • B41M5/20—Duplicating or marking methods; Sheet materials for use therein using electric current

Definitions

  • Recording paper of the electrolytic type is generally marked by passing the paper between a positive eroding metal anode electrode and a negative non-eroding cathode electrode.
  • the paper is impregnated with an electrolytically-conducting solution containing certain ingredients.
  • metal ions are introduced into the paper from the anode and reacted with one or more of the ingredients of the paper impregnant to form a colored mark on the recording paper.
  • the recording paper preferably should be white initially and should have the ability to produce marks having a density which is at least close in linear relationship to the current passed through the paper.
  • the density of the marked area should be variable uniformly in a range from white for zero current flow through grays for currents of intermediate magnitude to black for currents of maximum flow.
  • the mark preferably should be black to provide a good contrast with the white background.
  • the unmarked paper while stored in moist condition in sealed containers for extended periods of time prior to use should remain stable without chemical decomposition of its ingredients which would cause discoloration of the paper or affect the reproducibility of results without recorder adjustment. Further, the marked recording paper should not become discolored, give off unpleasant or other odors, or be subject to the transfer of the mark to adjacent materials.
  • the marked recording paper should be insensitive to light even after being repeatedly run through any of the conventional duplicating machines involving exposure to ultraviolet or other strong light sources.
  • a sheet of electrolytic recording medium is impregnated with an electr-olytically-conducting solution which contains a compound selected from the group consisting of ascorbic acid and erythorbic acid.
  • an electr-olytically-conducting solution which contains a compound selected from the group consisting of ascorbic acid and erythorbic acid.
  • the pH of the solution is between about five to about nine, and in the preferred form is buffered in a pH range between about six and about 7.5.
  • the invention includes a sheet impregnated with an electrolytically-conductive solution containing a compound selected from the group consisting of ascorbic acid and erythorbic acid.
  • a silver-containing anode is in contact with one part of the sheet, and a cathode is in contact with another part of the sheet so an electric current can be passed through the electrolyte to change its color where it is contacted by the anode.
  • the silver ions reelased into the paper by electrolytic erosion of the anode are reduced to metallic silver by the action of the ascorbic or erythorbic acid to leave a dense blue-black mark where the paper is contacted by the anode during the flow of electric current.
  • a clear, unblurred image is obtained with minimum diffusion of the mark.
  • the recording paper is stable both before and after marking, and the recorded mark does not fade, even after repeated exposure to light and heat such as occasioned by being passed through the copying machines using strong ultraviolent lamps.
  • a further advantage of the recording paper of this invention is that it has no perceptible odor either during or after recording.
  • the impregnant has a low vapor pressure and thus there is good reproducibility of results.
  • the impregnant is formulated with solid salts easy to handle and easily dissolved in water. The salts are inexpensive and readily obtainable.
  • a sheet of paper 10 impregnated with a conductive electrolyte containing ascorbic acid or erythorbic acid is passed between a stationary eroding anode 11 which contains silver, and a rotatable non-eroding cylindrical cathode 12 which has a prismatic platinum-iridium helical electrode wound around and projecting above its exterior surface.
  • the electrode 13 sweeps a spot longitudinally along a knife-edge 14 of the silvercontaining electrode.
  • Suitable formulations for impregnating ten square feet of porous recording paper stock having relatively high wet strength and a thickness of about three mils are as follows:
  • Example I Ingredients Quantity Erythorbic acid g 6 Sodium nitrate g Water ml- 100 This solution had a pH of 7.3, with the sodium nitrate acting primarily as the electrolyte.
  • Example II Ingredients Quantity Ascorbic acid g 2 Sodium nitrate g Sodium carbonate g 2 Sodium bicarbonate g 1 Water ml 100 The sodium carbonate and bicarbonate in this solution buffered to a pH of about 7.3.
  • Example III Ingredients Quantity Ascorbic acid g 3 Sodium nitrate g 10 Water ml 100 The solution of Example III had a pH of six.
  • any of the above solutions could be adjusted and buffered to any desired value by well-known buffering agents.
  • Formulations in the acid or base range can be made to work satisfactorily, but those with a pH in the vicinity of seven give the best over-all results with respect to clarity, density of the mark, and stability of the recorded sheet.
  • any of the above solutions can be buffered as high as 9.7 by including in them 5.3 grams of sodium carbonate and 4.2 grams of sodium bicarbonate.
  • the pH can be maintained at about nine with a solution which contains 35.8 grams of sodium biphosphate and two milliliters of one N NaOH and five hundred milliliters of water.
  • the diffuse reflectance optical density, as read on a Macbeth Quantalog Densitometer, Model RD-100, for the marks ranged from about 1.02 at maximum paper speed to about 1.26 at minimum paper speed.
  • the silver alloy electrode had a composition of about seventy-four percent silver, twenty-one percent copper, and four percent zinc. If the amount of silver is increased, the mark can be made darker for less current flow, but the silver electrode tends to wear faster. If the silver content is decreased much below about seventy-four percent, it wears better, but the mark is less dense.
  • Silver or silver alloys are the preferred anode electrodes because of the high optical density of the mark produced and because of its stable image. Silver produces univalent silver ions, which require less electrical energy than metal electrodes which produce multivalent ions. The use of silver thus generally results in the production of good density marks with a small expenditure of power. Silver alloy electrodes of the composition given above provide increased hardness, resistance to wear, and resistance to deformation without an appreciable effect on their marking qualities.
  • the cathode electrode may be made of any suitable conductive metal able to withstand the abrasive effects of the moving recording paper. Metals found acceptable are platinum, platinum alloys, steel, and others known in the art.
  • the reducing agent is about two percent to about three percent by weight.
  • the amount of reducing agent can be varied from a minimal amount which barely reduces enough silver to make a visible mark up to the solubility limit of the reducing agent.
  • various combinations of the ascorbic and erythorbic acids can be used rather than either of them alone.
  • Typical concentrations of reducing agent can vary between about one and about ten percent by weight. The required concentration is selected to be compatible with conventional recording speeds and marking apparatus sensitivity.
  • the sodium nitrate is used as an electrolyte.
  • suitable electrolytes which can be used are the alkali metal nitrates and sulfates, and ammonium nitrate or sulfate.
  • concentration of the electrolyte salt can be varied as required for changing the electrical conductivity of the solution. Such variations can be from minimal amounts to the solubility limits of the salts used. Combinations of the various salts can be used, if desired.
  • the recording medium of this invention was prepared by impregnating porous white paper or other porous support with high wet strength with an impregnant prepared in accordance with the above disclosure.
  • the impregnant was permitted to distribute itself even throughout the paper. Excess impregnant was removed by passing the paper between pressure rollers, so that when ready for use in a recorder, the impregnated paper had about twenty-five to fifty percent moisture by weight. To retard evaporation and keep the moisture content of the paper substantially uniform, the impregnated paper was stored in a suitable sealed container until needed.
  • An electrolytic recording medium comprising a sheet impregnated with an electrolytically-conducting solution containing a compound selected from the group consisting of ascorbic acid and erythorbic acid, the impregnated sheet including between about 25% and about 50% of moisture by weight of the sheet and a sealed container disposed around the sheet to maintain the moisture content between about 25% and about 50% by weight.
  • An electrolytic recording medium which includes a compound for buffering the pH of the eleetrolytically-conducting solution between about six and about 7.5.
  • An electrolytic recording medium which includes sufiicient sodium carbonate and sodium bicarbonate to buffer the electrolytic solution to a pH of about 7.3.
  • An electrolytic recording process for marking a sheet impregnated with an electrolytically-conductive solution containing a compound selected from the group consisting of ascorbic acid and erythorbie acid comprising the steps of passing an electric current through said sheet while a silver containing anode is in contact with one part of the sheet, and a cathode is in contact with any other part of the sheet to produce a colored mark on the anode side of the sheet.
  • the electrolytically-conductive solution includes a complexing agent for tying up copper and iron.
  • An electrolytic recording medium which includes an electrolyte selected from the group consisting af alkali metal and ammonium nitrates and sulfates.
  • An electrolytic recording medium which includes a complexing agent for tying up copper and iron ions.

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  • Printing Plates And Materials Therefor (AREA)
  • Printing Methods (AREA)
US600893A 1966-12-12 1966-12-12 Electrolytic recording medium Expired - Lifetime US3402109A (en)

Priority Applications (3)

Application Number Priority Date Filing Date Title
US600893A US3402109A (en) 1966-12-12 1966-12-12 Electrolytic recording medium
GB44178/67A GB1148132A (en) 1966-12-12 1967-09-28 Electrolytic recording medium
DE1696215A DE1696215B2 (de) 1966-12-12 1967-10-11 Elektrolytisches Aufzeichnungsmaterial und seine Verwendung

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US600893A US3402109A (en) 1966-12-12 1966-12-12 Electrolytic recording medium

Publications (1)

Publication Number Publication Date
US3402109A true US3402109A (en) 1968-09-17

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Family Applications (1)

Application Number Title Priority Date Filing Date
US600893A Expired - Lifetime US3402109A (en) 1966-12-12 1966-12-12 Electrolytic recording medium

Country Status (3)

Country Link
US (1) US3402109A (enrdf_load_stackoverflow)
DE (1) DE1696215B2 (enrdf_load_stackoverflow)
GB (1) GB1148132A (enrdf_load_stackoverflow)

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3113910A (en) * 1959-08-20 1963-12-10 Eastman Kodak Co Process for electro-development of photographic images
US3152903A (en) * 1959-04-30 1964-10-13 Minnesota Mining & Mfg Reproduction system
US3278366A (en) * 1961-04-28 1966-10-11 Telefunken Patent Storage device

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3152903A (en) * 1959-04-30 1964-10-13 Minnesota Mining & Mfg Reproduction system
US3113910A (en) * 1959-08-20 1963-12-10 Eastman Kodak Co Process for electro-development of photographic images
US3278366A (en) * 1961-04-28 1966-10-11 Telefunken Patent Storage device

Also Published As

Publication number Publication date
DE1696215C3 (enrdf_load_stackoverflow) 1974-05-22
DE1696215B2 (de) 1973-10-18
GB1148132A (en) 1969-04-10
DE1696215A1 (de) 1972-03-23

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