US3769629A - Multicolor permanent and erasable printing - Google Patents

Multicolor permanent and erasable printing Download PDF

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Publication number
US3769629A
US3769629A US00275989A US3769629DA US3769629A US 3769629 A US3769629 A US 3769629A US 00275989 A US00275989 A US 00275989A US 3769629D A US3769629D A US 3769629DA US 3769629 A US3769629 A US 3769629A
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United States
Prior art keywords
electrode
mark
marking
permanent
reference electrode
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Expired - Lifetime
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US00275989A
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English (en)
Inventor
C Sambucetti
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International Business Machines Corp
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International Business Machines Corp
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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

Definitions

  • a salt bridge may be provided l g 15/ between a reference electrode and the recording me- 1 0 fem-c 412;; g dium to prevent a counter-mark during erasing.
  • a porous recording medium such as paper
  • a conductive salt such as ammonium fluoride, ammonium oxalate, or potassium fluoride or the like
  • a reducing agent such as ascorbic acid, stannous chloride, stannous sulfate, or the like.
  • Printing is effected through the use of a silver or silver alloy anode and a cathode of platinum, platinum alloy, gold, steel, etc.
  • the erase electrode and the'reference electrode When a sacrificial area is used, the erase electrode and the'reference electrode must be spaced relatively far apart, and thus erasing becomes difficult because the conductivity between electrodes becomes much less than that available when the cur- 7 rent is passed directly through the thickness of the recording medium..-To compensate, high erasing potentials must be used. Further, the reaction time-of the system is slower. When the same reference electrode is used during the non-permanent marking mode of operation, the distance between the marking electrode'and reference electrode is also great and thus high marking potentials are required.
  • the marking electrode rapidly moves in anessentially unpredictable manner to various X Y coordinates on the marking area.
  • the distance between the marking/erasing electrode and the reference electrode is not only large but varies considerably'as themarking electrode traces out the graphic illustration.
  • the conductivity at the marking spots varies considerably.
  • the marking and erasing voltages must be made variable and dependent upon the position of the marking/erasing electrode.
  • the inventive system which solves the counter-marking problem without using sacrificial areas.
  • the marking/erasing and reference electrodes can be located close to each other and indeed they may be located in alignment on opposite sides of the recording medium.
  • the dual operating mode feature is-attained by impregnating a recording medium, such as paper, with an electrolyte such as potassium fluoride, ammonium fluoride, ammonium oxalate or the like along with both a reducing agent such as ascorbic acid, stannous chloride, stannous'sulfate or the like, and an electrochromic material such as a Redox system or a pH indicator.
  • the marking/erasing electrode is in the form of a permanent or erasable marking electrode element and an erase electrode'element positioned in a holder which is rotatable to place either of the electrode elements into contact with the recording medium.
  • the marking electrode element is formed from silver or its. alloys while the erase electrode element is formed from platinum or its alloys.
  • a reference electrode is also provided.
  • the silver marking electrode element acts as either a permanent or erasable markingelectrode merely by changing the polarity of the potential supply thereto.
  • a conductive salt bridge positioned between the reference electrode and the recording medium.
  • the salt bridge provides the necessary conductivity but as the electrolyte in the salt bridgedoes not contain any electrochromic material, it will produce no marking at either polarity.
  • FIG. 1 illustrates one embodiment of the dual mode electrochemical printing system of the present invention
  • FIG. 2. illustrates a second embodiment of thedual DETA LED DESCRIPTION "OF THE PREFERRED EMBODIMENTS
  • FIG. 1 illustrates one embodiment of the permanent or erasable electro-chemical printing system of the present invention.
  • Recording medium 1 which may be porous paper, is positioned overa conductive base 4 of platinum, gold or platinum or gold plated-mylar or epoxy boards. Other suitable conductive materials may be used for the base.
  • the recording medium which may for example, be in the form of a continuous roll of paper (not shown) with the paper being unrolled and pulled across the base/,4, as needed or individual sheets or a continuous loop, is impregnated with a conductive salt such as potassium fluoride-ammonium fluoride, ammonium oxalate or the like, a reducing agent such as ascorbic acid, stannous chloride, stannous sulfate or the like and an electrochromic materialsuch as a pH indicator or a Redox system.
  • a conductive salt such as potassium fluoride-ammonium fluoride, ammonium oxalate or the like
  • a reducing agent such as ascorbic acid, stannous chloride, stannous sulfate or the like
  • an electrochromic materials uch as a pH indicator or a Redox system.
  • an electrochromic material is used which produces a color in response to a basic condition of the electrolyte. Examples of suitable pH indicators-are given in the
  • a silver or silver alloy marking element 8 coupled to reversible polarity sources 10 and 14 through a rotatable conductive electrode element holder 7.
  • the reversible polarity sources 10 and 14 are illustrated as being formed by pairs of batteries 9, 11 and 13, 15.- In fact, any D.C. source of potential which can reverse the polarity of its out-put potential may be used.
  • the electrode element 8 is electrically connected to only one of the sources 10, 14 at any instant of time to accomplish marking or erasing. The significance of the provision of the two reversible polarity sources will be explained below.
  • an erase electrode element 6 is also attached to' the holder 7 . Two reference electrodes, one used to the exclusion of the other, are provided in the form of electrode 12 positioned over a sacrificial area 2 of the recording medium 1 and the conductive base 4.
  • the holder 7 is rotated so that the silver electrode element 8 is in contact with the recording medium 1 and either switch 16 or 20 is closed so that the silver electrode is provided with a potential positive with respect to the reference electrode.
  • switch 16 is closed, the reference electrode takes the form of the conductive base 4, while if switch 20 is closed, the reference electrode takes the form of electrode 12.
  • switch 16 When switch 16 is closed, current will flow directly through the thickness of the recording medium. Since the distance between the reference electrode in the form of base 4 and marking electrode element 8 is small, a dense black mark will appear.
  • switch 20 is closed, the distance between the marking electrode element and reference electrode is increased, thereby decreasing the conductivity be- .tween electrodes. As a result, a less dense mark may appear. In either case, the mark appears as a result of the creationof positive silver ions which flow to the paper and are there reduced by the reducing agent back to metal form. 1
  • the same silver electrode element 8 may be used.
  • either switch 18m 22 would be closed so that the marking electrode element 8 appears-at a negativepotential with ,resect to the reference electrode.
  • switch 18 When switch 18 is closed, the top surface of the recording medium l in the vicinity'of the electrode element 8 becomes alkaline.
  • This condition is noted by a color mark produced as a result of including an electrochromic material in the medium impregnant.
  • the color of this erasable mark will generallydiffer'fromthat provided as a result of a permanent mark. The particular color will depend uponthe particular electrochromic'material used.
  • holder 7 is rotated so that the erase electrode element 6 is positioned in contact with the recording medium 1.
  • switch 20 would be closed whereby electrode element 6 is at a potential positive with respect to reference electrode 12.
  • the erasable mark produced by the silver electrode element 8 is erased while a counter-mark is produced in the sacrificial area 2 in the vicinity of thereference electrode 12.
  • Reference electrode 4 would not be used during the'erasing process sincejrecordingmedium 1 is translucent and thus a counter-mark produced on the bottom surface ofmedium 1 during the erasing process would be visible from the top surface.
  • a difficulty may arise if an erasable mark is produced using the Conductive base'4 as the reference electrode.
  • the conductivity between the marking electrode element'8 and the base 4 is strong and thus an intense mark would be produced.
  • reference electrode 12 To effect erasing, reference electrode 12 must be used for the reasons indicated above. Since the distance between electrode 12 and the erase electrode element 6 is much greater than the distance between electrode element 8 and base 4, the conductivity 'decreases and thus unless the potential of battery 14 is made substantially greater than that of battery 9, a complete erasure may not result. Therefore, it would be preferable to use source 14 when creating and erasing erasable marks. On the other hand, it may be preferable to use source 10 and base 4 as the reference electrode when producing permanent marks.
  • source 10 may be removed and both permanent or erasable markings produced using only source 14 and reference electrode 12.
  • the-marking electrode .element 8 has been specified as consisting'of silver or its alloys, this electrode can be composed of any metal which dissolves releasing ions into the recording medium. Among these metals, in addition to silver, are molybdenum and chromium.
  • the reference electrode has been indicated as being either of gold or platinum. Other materials may be utilized such as stainless steel, copper, nickel or palladium. Further, it is also possible to use the erase electrode element 6 as a marking'electrode for producing erasable marks.
  • FIG. 2 illustrates a second embodiment of the invention wherein the problems associated with the use of a sacrificial area on therecording medium are alleviated.
  • a sacrificial area 2 must be provided so that the countermark does not appear in'the-recording area.
  • FIG. 2 Like elements in FIG. 1 and FIG. 2 carry common numerical designations.
  • FIG. 2 differs from FIG. 1 in the provision of a non-metallic conductive interface 26 between the conductive base acting as a reference electrode and recording medium 1.
  • This conductive non-metallic interface is preferably comprised of a salt bridge containing an electrolyte but no electrochromic material.
  • the salt bridge provides a high conductivity non-metallic reference terminal in contact with the recording medium and this new terminal will produce no mark on the medium regardless of its polarity with respect to the erase electrode.
  • the salt bridge may be a system formed of three components, water, a conductive salt (electrolyte) and an organic protein that gels, such as gelatin or agar. Depending upon the relative amounts of salt and agar, different consistencies and conductivity can be obtained. Excellent salt bridges are obtained using 5 grams agar and 30 grams calcium chloride per 100 grams of waer. Other salts are known that can replace the chloride ions such as nitrates, sulfates and fluorides. As a matter of fact, fluoride can be used as a common electrolyte for both the conductivity on the paper, that is, the recording medium and the salt bridge.
  • the salt bridge is formed of a solidifying gel containing the electrolyte which provides excellent conductivity while not causing markings on the recording medium at either polarity.
  • a conductive nonmetallic protective film situated between the salt bridge and the recording medium.
  • This protective film may take the form of a layer of wet paper or cellophane.
  • permanent markings can be formed in the manner disclosed with respect to FIG. 1. That is, switch 16 is closed and marking electrode element 8 is placed in contact with the recording medium 1. Since the marking electrode element 8 is at a positive potential with respect to the reference electrode, in the form of base 4 and salt bridge layer 26, ions of the electrode material are released into the paper where they are reformed into the metal to produce a permanent mark. Erasable marks are provided by opening switch 16, closing switch 18, and retaining electrode element 8 in contact with the recording medium 1. In this situation, electrode element 8 is at a potential negative with respect to the reference electrode, causing the area on the top surface of the medium 1 in the vicinity of electrode element 8 to become alkaline. Due to the electrochromic material in the medium, a color mark appears.
  • holder 7 is rotated so that erase electrode element 6 is in contact with the medium 1 and switch 16 is closed. Since the erase electrode element 6 is at a positive potential with respect to the reference electrode, the area about the electrode becomes acidic and the color mark disappears. Were it not for the non-metallic conductive interface 26, the underside of recording medium 1 would be in contact with the metallic base 4 and a counter-mark would appear. However, the imposition of the interface 26 containing no color indicators, prevents a counter-mark from appearing.
  • FIG. 3 shows a third embodiment of the invention wherein'both' the marking/erasing electrode and the reference electrode are located close to each other on the same surface of the recording medium 1.
  • the marking/erasing electrode 30 may be formed of platinum or its alloys and is located in a hollow core of a cylinder formed of insulating materials such as teflon. Surrounding this core is a cylindrically shaped salt bridge 34. Base 4 in this instance may be formed of non-conductive material or an insulation layer could be postioned between it and medium 1. Operation of this configuration is identical to the operation of the embodiment of FIG. 2. With electrode 30 being platinum only erasable marks can be made. Permanent marks can be provided by interchanging a silver electrode for the platinum electrode.
  • An electro-chemical printing system comprising:
  • a marking electrode composed of a metal that dissolves releasing ions when a first polarity potential difference is applied between it and a reference electrode for forming a permanent mark on said medium, said marking electrode producing an erasable mark when a second polarity potential difference, opposite said first polarity potential difference, is applied between it and said reference electrode,
  • a reversible polarity potential source coupled between said marking and erase electrodes and said reference electrode.
  • the electro-chemical printing system of claim 2 further including a conductive rotatable electrode holder holding said marking and erase electrodes and being coupled to said potential source.
  • An electro-chemical printing system comprising;
  • a recording medium formed of a porous material impregnated with potassium fluoride, ascorbic acid and an electrochromic material
  • a silver mark electrode for generating permanent or erasable marks on said medium and positioned on a first surface thereof a platinum mark/erase electrode positioned on said first surface a reference electrode positioned on said medium,
  • a reversible polarity potential source coupled be tween said reference electrode and said mark and mark/erase electrodes
  • the printing system of claim 6 further including a rotatable electrode holder wherein are mounted said mark and mark/erase electrodes.

Landscapes

  • Fax Reproducing Arrangements (AREA)
  • Duplication Or Marking (AREA)
  • Dot-Matrix Printers And Others (AREA)
  • Electronic Switches (AREA)
  • Electrochromic Elements, Electrophoresis, Or Variable Reflection Or Absorption Elements (AREA)
  • Devices For Indicating Variable Information By Combining Individual Elements (AREA)
US00275989A 1972-07-28 1972-07-28 Multicolor permanent and erasable printing Expired - Lifetime US3769629A (en)

Applications Claiming Priority (1)

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US27598972A 1972-07-28 1972-07-28

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US3769629A true US3769629A (en) 1973-10-30

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US (1) US3769629A (enrdf_load_stackoverflow)
JP (1) JPS5611591B2 (enrdf_load_stackoverflow)
DE (1) DE2338016A1 (enrdf_load_stackoverflow)
FR (1) FR2237437A5 (enrdf_load_stackoverflow)
GB (1) GB1417223A (enrdf_load_stackoverflow)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4121260A (en) * 1976-10-14 1978-10-17 Xerox Corporation Transceiver system for visible images
US4137538A (en) * 1977-08-11 1979-01-30 Klein Associates, Inc. Process and apparatus for compatible wet and dry paper signal recording
US5929881A (en) * 1994-04-26 1999-07-27 Seiko Epson Corporation Ink jet recording head having improved arrangement of electrodes

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2007163758A (ja) * 2005-12-13 2007-06-28 Oita Univ エレクトロクロミックフィルム印字装置

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4121260A (en) * 1976-10-14 1978-10-17 Xerox Corporation Transceiver system for visible images
US4137538A (en) * 1977-08-11 1979-01-30 Klein Associates, Inc. Process and apparatus for compatible wet and dry paper signal recording
US5929881A (en) * 1994-04-26 1999-07-27 Seiko Epson Corporation Ink jet recording head having improved arrangement of electrodes
US6073321A (en) * 1994-04-26 2000-06-13 Seiko Epson Corporation Manufacturing method for an ink jet recording head

Also Published As

Publication number Publication date
JPS4954043A (enrdf_load_stackoverflow) 1974-05-25
GB1417223A (en) 1975-12-10
FR2237437A5 (enrdf_load_stackoverflow) 1975-02-07
JPS5611591B2 (enrdf_load_stackoverflow) 1981-03-16
DE2338016A1 (de) 1974-02-14

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