EP0097832A2 - Procédé pour régler la valeur du pH dans la zone de réaction d'un appareil pour l'impression électrolytique - Google Patents

Procédé pour régler la valeur du pH dans la zone de réaction d'un appareil pour l'impression électrolytique Download PDF

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Publication number
EP0097832A2
EP0097832A2 EP83105437A EP83105437A EP0097832A2 EP 0097832 A2 EP0097832 A2 EP 0097832A2 EP 83105437 A EP83105437 A EP 83105437A EP 83105437 A EP83105437 A EP 83105437A EP 0097832 A2 EP0097832 A2 EP 0097832A2
Authority
EP
European Patent Office
Prior art keywords
reaction zone
anode
surface layer
cathode
value
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.)
Granted
Application number
EP83105437A
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German (de)
English (en)
Other versions
EP0097832B1 (fr
EP0097832A3 (en
Inventor
William Emmett Bernier
Charles Robert Pigos
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.)
International Business Machines Corp
Original Assignee
International Business Machines Corp
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Filing date
Publication date
Application filed by International Business Machines Corp filed Critical International Business Machines Corp
Publication of EP0097832A2 publication Critical patent/EP0097832A2/fr
Publication of EP0097832A3 publication Critical patent/EP0097832A3/de
Application granted granted Critical
Publication of EP0097832B1 publication Critical patent/EP0097832B1/fr
Expired legal-status Critical Current

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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
    • B41M5/20—Duplicating or marking methods; Sheet materials for use therein using electric current

Definitions

  • the invention relates to a method for controlling the pH of the pressure reaction zone of an electrolytic printer having at least one anode and one cathode, with pressure control means, with a recording medium which has a treated surface layer which contains a leuco dye and with a supply of liquid for Moisten the record carrier.
  • the problem of printing electrode wear is associated with the effects of electrolytic or chemical reactions that occur both at the anode and at the cathode of the printer.
  • electrolytic printing either the anode is exposed to excessive acid and the resulting chemical wear, or the cathode is subject to excessive base wear.
  • the approaches mentioned can mitigate this aspect of electrode wear, but they cannot reduce electrode consumption prevent.
  • the printing electrodes can be plated or covered with a resistant protective layer.
  • the number of protective materials that meet all the requirements for coating the printing electrodes in this work environment is small, and coating using ordinary methods is difficult.
  • such measures are complex and reduce the throughput rates and the print quality of electrolytic printers.
  • the invention achieves the object of specifying a method for reducing or avoiding electrochemically caused wear on the printing electrodes of an electrolytic matrix printer, in which careful pH buffering of the surface of the recording medium for the purpose of limiting the effects of electrolytic Responses to the printing electrodes is used and whereby their electrode wear can be dynamically adjusted without having to change the printing process or the pass rate of the printer and without affecting the print quality or stability.
  • the advantages achieved by the invention are essentially to be seen in the fact that the correct pH range can be achieved by forming it in the printing surface of the recording medium and that wetting agents used to support the electrolytic printing process can be pH adjusted to achieve the correct pH of the surface of the recording medium and such buffering to compensate for excessive acid or base material generated on the electrodes, thereby reducing or deleteriously influencing them even be completely eliminated.
  • the recording medium 10 consists of a surface layer 12, a conductive layer 14 and a support layer 16 (FIG. 1).
  • the surface layer 12 is approximately 5 to 50 g thick. It contains five main components, one of which is a pigment of a suitable color, generally clay. The clay component is selected to increase or decrease the gloss, whiteness or absorption of the surface layer in accordance with the end use.
  • the surface layer 12 also contains as components a leuco dye, a color stabilizer, a binder and an electrolyte.
  • a leuco dye is a dye whose chromophores are not visible under normal room conditions. However, they can be permanently shifted into the visible spectrum if a pulse of sufficient energy is applied for a suitable period of time.
  • the conductive layer 14 is formed from a thin metal foil, such as aluminum, with a thickness of approximately 1000 A or from a coating of sodium chloride (NaCl) or a suitable other salt.
  • the base layer 16 serves only, as its name suggests, to support the surface layer 12 and the conductive layer 14. It is approximately 15 to 20 nm thick and is made from ordinary paper.
  • a possible electrolytic printing device which is a recording medium which is produced in accordance with the preceding description schematically illustrated in Fig. 2.
  • the record carrier 10 is in the vicinity of an electrode 18, the anode brought by a suitable transport mechanism.
  • the printing electrode 18 can be made of a tungsten alloy or of a member coated with a ruthenium oxide which is very durable and shows little or no tendency for chemical penetration into the printing process.
  • the base electrode 20 or cathode is made of a similar, if not identical, material. Although only one anode and cathode are shown in FIG. 2 for simplicity, a typical printhead has at least 250 print electrodes, as shown in FIG. 3.
  • a control circuit 22 of conventional type is connected between the voltage source V and the printing electrode 18.
  • a control circuit which is particularly suitable for use in an electrolytic color matrix printer is described in the US patent application Ser. No. 323 843.
  • the control circuit 22 serves to apply a voltage pulse of suitable amplitude or width to the printing electrode 18.
  • the pulses are supplied to the desired printing electrodes by the control circuit 22 in accordance with commands received from a text or graphics source connected via the input line 24.
  • a liquid reservoir 26 and electrode 28 are provided.
  • the details of a typical liquid measuring system in which the reservoir 26 and the electrode 28 can be used are given in US patent application Ser. No. 240 332.
  • the electrode is for uniformly applying a very small amount of liquid to the surface layer 12 of the recording Carrier 10 suitable before the latter passes the pressure electrode 18.
  • the use of liquid on the surface layer 12 serves a dual purpose. Since the printing electrode 18 is placed in loose contact with the surface layer 12, the presence of a liquid on the latter reduces the frictional forces and thereby increases the printing speed. In addition, the presence of the liquid significantly supports the electrolytic pressure reaction by increasing the conductivity of the recording medium 10, in particular its surface layer 12. Water is a preferred liquid for economic and safety reasons, but other liquids which are compatible with the components of the surface layer can also be used successfully .
  • print reaction zone means the area in which the printing takes place, that is the surface layer 12 of the recording medium 10, which lies directly next to the printing electrodes 18 and 20.
  • Printing is done by supplying the pulses obtained to the moistened surface of the recording medium 10. As a result of these pulses, free bromine ions which are in the surface layer 12 as part of the electrolyte components are converted to form bromine on the printing electrode 18. This response is in accordance with and
  • reaction (1) converts the leuco dye, ie causes it to shift permanently into the visible spectrum, with a printed picture element next to the printing electrode 18 arises.
  • reaction (2) causes excess acid at the anode due to the presence of extra hydrogen cations.
  • the printing electrode is etched or electrochemically eroded if an unbuffered surface layer 12 is used or if the pH of the surface in the reaction zone is 5 or less.
  • this electrochemically induced wear also affects the insulation material surrounding the anode, causing the printhead surface to be eroded and grooved.
  • portions of the pressure electrode material were plated on the base electrode 20, creating burrs of deposited material. This reduces the print quality and the efficiency of the bromine production, but except for the extreme cases described above, there is little wear on the cathode.
  • the electrochemical reaction generates 20 processes on the cathode or base electrode accordingly
  • these excessive alkaline ions attack the surrounding material and cause an electrochemically generated erosion at the cathode.
  • the base ions produce little or no wear on the anode.
  • One way of controlling the pH of the reaction zone is to buffer the surface layer 12 by introducing a suitable material.
  • Either carbonated lime or phosphoric acid potash were found to be suitable for this task.
  • the carbonated lime causes buffering in accordance with the reactions on the anode and on the cathode.
  • the reactions by which the phosphoric acid potassium reaches the buffering, and it should be noted that the potassium does not enter into these reactions, are (6) on the anode and (7) on the cathode.
  • a pH sensor 30 is arranged in the immediate vicinity of the pressure electrode 18. It measures the pH value of the reaction zone on the surface layer 12 and sends a signal proportional to the measured pH value signal of a comparison circuit 32 in which it is compared with the desired pH.
  • the comparison circuit 32 generates an Error signal proportional to the degree of deviation between the actual and desired pH that is supplied to the buffer agent stock 34.
  • An outlet valve (not shown) of conventional design is then opened by the error signal to the extent that the correct amount of buffering agent flows via line 34 into the liquid storage container 26 and then brings the error signal to zero.
  • this arrangement would work slowly, it is a means of dynamically adjusting the pH, which is preferred rather than waiting for a batch of new dampening fluid to be combined with another record carrier to be inserted into the printer. Accordingly, the invention completely alleviates or avoids the harsh effects of excessive acids or base material by stably tuning them using buffers.

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  • Printing Methods (AREA)
  • Electronic Switches (AREA)
EP83105437A 1982-06-25 1983-06-01 Procédé pour régler la valeur du pH dans la zone de réaction d'un appareil pour l'impression électrolytique Expired EP0097832B1 (fr)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US392208 1982-06-25
US06/392,208 US4453171A (en) 1982-06-25 1982-06-25 Reduced electrode wear in electrolytic printing by pH control of the print reaction zone

Publications (3)

Publication Number Publication Date
EP0097832A2 true EP0097832A2 (fr) 1984-01-11
EP0097832A3 EP0097832A3 (en) 1985-07-03
EP0097832B1 EP0097832B1 (fr) 1988-10-26

Family

ID=23549717

Family Applications (1)

Application Number Title Priority Date Filing Date
EP83105437A Expired EP0097832B1 (fr) 1982-06-25 1983-06-01 Procédé pour régler la valeur du pH dans la zone de réaction d'un appareil pour l'impression électrolytique

Country Status (4)

Country Link
US (1) US4453171A (fr)
EP (1) EP0097832B1 (fr)
JP (1) JPS597091A (fr)
DE (1) DE3378307D1 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4109198A1 (de) * 1991-03-18 1992-09-24 Sandrock Stefan Verfahren zur beeinflussung des ph-wertes an oberflaechen von festkoerpern in fluessigen medien

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US7584539B2 (en) * 2006-10-16 2009-09-08 Eastman Kodak Company Electropolishing of inkjet printer components

Family Cites Families (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3974041A (en) * 1973-12-10 1976-08-10 Canon Kabushiki Kaisha Image recording member with zeolitic water containing compounds
DE2458128C3 (de) * 1973-12-10 1981-07-16 Canon K.K., Tokyo Stromempfindliches Bildaufzeichnungsmaterial

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE4109198A1 (de) * 1991-03-18 1992-09-24 Sandrock Stefan Verfahren zur beeinflussung des ph-wertes an oberflaechen von festkoerpern in fluessigen medien

Also Published As

Publication number Publication date
DE3378307D1 (en) 1988-12-01
JPS597091A (ja) 1984-01-14
EP0097832B1 (fr) 1988-10-26
US4453171A (en) 1984-06-05
JPH0247353B2 (fr) 1990-10-19
EP0097832A3 (en) 1985-07-03

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