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US3124804A - Electrostatic recording head - Google Patents

Electrostatic recording head Download PDF

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Publication number
US3124804A
US3124804A US3124804DA US3124804A US 3124804 A US3124804 A US 3124804A US 3124804D A US3124804D A US 3124804DA US 3124804 A US3124804 A US 3124804A
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US
United States
Prior art keywords
electrodes
recording head
pin
high voltage
recording
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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
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English (en)
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    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06K—GRAPHICAL DATA READING; PRESENTATION OF DATA; RECORD CARRIERS; HANDLING RECORD CARRIERS
    • G06K1/00—Methods or arrangements for marking the record carrier in digital fashion
    • G06K1/12—Methods or arrangements for marking the record carrier in digital fashion otherwise than by punching
    • G06K1/128—Methods or arrangements for marking the record carrier in digital fashion otherwise than by punching by electric registration, e.g. electrolytic, spark erosion
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G15/00—Apparatus for electrographic processes using a charge pattern
    • G03G15/22—Apparatus for electrographic processes using a charge pattern involving the combination of more than one step according to groups G03G13/02 - G03G13/20
    • G03G15/32—Apparatus for electrographic processes using a charge pattern involving the combination of more than one step according to groups G03G13/02 - G03G13/20 in which the charge pattern is formed dotwise, e.g. by a thermal head
    • G03G15/321—Apparatus for electrographic processes using a charge pattern involving the combination of more than one step according to groups G03G13/02 - G03G13/20 in which the charge pattern is formed dotwise, e.g. by a thermal head by charge transfer onto the recording material in accordance with the image
    • G03G15/325—Apparatus for electrographic processes using a charge pattern involving the combination of more than one step according to groups G03G13/02 - G03G13/20 in which the charge pattern is formed dotwise, e.g. by a thermal head by charge transfer onto the recording material in accordance with the image using a stylus or a multi-styli array
    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/23—Reproducing arrangements
    • H04N1/29—Reproducing arrangements involving production of an electrostatic intermediate picture

Definitions

  • the recording head of the present invention is designed primarily to record electrical signals on a moving paper tape, but may be equally useful in recording such signals on a rotating drum or a revolving disc.
  • the paper tape on which the signals are recorded comprises a layer of carbon impregnated paper coated with an insulating layer of plastic such as polyethylene or vinyl. The carbon impregnation of the paper renders it electrically conductive and in the recording operation, this portion of the paper is normally maintained at ground potential.
  • the recording head comprises a plurality of free end pin electrodes disposed in a parallel array and connected to a high voltage pulser circuit.
  • a single ground electrode was disposed in close proximity to the free ends of the pin electrodes but insulated therefrom.
  • the free ends of the pin electrodes are located in close proximity normal to the insulating coating of the paper.
  • High voltage pulses Lffid from the pulser to each of the pin electrodes cause an electrical discharge across the gap between the end of the pin electrode and the ground electrode.
  • Some of the ions generated in the electrical discharge are deposited by ion migration on the polyethylene or vinyl surface. The surface resistivity of materials of this type is very high and if desired, the electrical signals may be stored in this form for prolonged periods of time.
  • the latent image defined by the static charges may be rendered visible by passing the tape through a dry ink or pigment powder bath.
  • the ink powder may comprise a finely granulated mixture of resins and carbon that is electrically conductive and is attracted by the static charge so as to adhere to the tape. Any loose powder is cleaned from the tape and the ink powder attracted by the static charges is fixed thereon either by a thermal process or by pressure fixing.
  • a current limiting resistor is necessary in series in each of the pin electrode circuits.
  • This resistor must be located between the pulse source and the pin electrode.
  • the high voltage pulses fed to the pin electrodes may have a magnitude of approximately minus 2,000 volts. Just prior to the instant that discharge occurs, all of this potential dilference appears across the gap between the electrodes. When the electrical discharge is initiated, the voltage across the gap decreases substantially, and a major portion of the high voltage pulses appears as a potential drop across the resistor. This means that a relatively low potential exists between the pin elect-rode and the portion of the paper tape at ground potential. Consequently, there is a relatively low accelerating potential tending to repel the ions to the insulating coating.
  • the phrase connected in series describes a circuit arrangement which may include elements in addition to the ground electrode and the current limiting resistor, but irrespective of the precise arrangement utilized, the current which flows in the current limiting resistor is the same as the current which passes through the ground electrode.
  • Still another disadvantage of the prior art devices is the fact that the insulating material, such as epoxy resin or lime glass, separating the pin electrodes from the ground electrode tends to melt or deteriorate under the high temperatures produced by the electrical discharge. Insulating materials of this type also tend to be water absorbing which increases the possibility of shorting out the high voltage pulses.
  • the insulating material such as epoxy resin or lime glass
  • FIGURE 1 is a longitudinal sectional view of the electrostatic recording head of the present invention.
  • FIGURE 2 is an end view taken on line 22 of FIG- URE 1;
  • FIGURE 3 is an enlarged fragmentary view of a portion of FIGURE 2;
  • FIGURE 4 is a View taken on line 4-4 of FIGURE 3;
  • FIGURE 5 is a View taken on line 55 of FIGURE 4.
  • FIGURE 6 is a schematic diagram of the electrical connections for the pin electrodes.
  • the electrostatic recording head of the present invention is designated generally by the numeral 10 and comprises a plurality of high voltage pin electrodes 11, a plurality of ground pin electrodes 12, supporting pin holders 13 and 14, and an insulating layer 15 separating the pin electrodes 11 and 12.
  • the pin holders 13 and 14 are formed with longitudinal grooves 16 and 17,
  • the recording head 10 is assembled by inserting the.
  • the pin electrodes are then bonded into place by potting the pin holders 13 and 14 with epoxy resin or other suitable potting compound.
  • a sheet of quartz 15 having a thickness of approximately .003'in. is bonded against the parallel pin electrodes 11 or 12.
  • the quartz sheet is then lapped down to a thickness of approximately .0015 inch.
  • the other pin holder 13 or 14 is then bonded against the face of the quartz sheet 15 with the pin electrodes 11 and 12 lying parallel to each other at a minimum distance apart.
  • the end surface 20 of the recording head 10 is then lapped to some degree of smoothness.
  • the end surface 20 lies in a plane defined by the free ends of the pin electrodes 11 and 12 and comprises the recording surface for the head 10.
  • the assembled pin holders 13 and 14 and the conductors 18 and 19 are then placed in a suitable mold and are potted with epoxy resin to form a unitary structure of suitable size.
  • FIGURE 6 there is illustrated a schematic diagram of the electrical connections to the pin electrodes 11 and 12.
  • the high voltage electrodes 11 are connected directly to a pulser 21 and the ground electrodes 12 are connected in series through resistors 22 to ground.
  • the pulser 21 provides output pulses having a magnitude of approximately minus 2000 volts to each of the electrodes 11 for the recording operation to be described hereinafter.
  • the paper tape 23 comprises a plastic or insulating layer 24 which may be polyethylene or vinyl and a conductive layer 25 which may be impregnated with carbon or other electrical conductive material.
  • the recording head 10 is disposed above the tape 23 with the recording surface 20 parallel to the top surface of the plastic layer 24 but separated therefrom by a few thousandths of an inch.
  • the tape 23 is moved at some predetermined speed past the recording surface 20 during the recording operation.
  • the conductive layer 25 is normally maintained at ground potential by being in contact with metal rollers or metal guide pins connected to the chassis of the recorder.
  • negative high voltage pulses are fed to selective ones of the high voltage pin electrodes 11 according to the sequence in which the signals are to be recorded.
  • the pin electrodes 11 and 12 and a resistor 22 form a series circuit for a recording channel between the pulser 21 and a plane of reference potential, conventionally designated as ground.
  • a plane of reference potential conventionally designated as ground.
  • the static charges deposited on the insulating layer 24 may be rendered visible by passing the tape 23 through a dry ink powder bath.
  • the particles comprising the ink powder are attracted by the static charge and are caused to adhere to the plastic layer 24. Any loose powder is cleaned from the tape and the portion attracted by the static charge is fixed by a thermal process or pressure fixing.
  • the resultant coded information stored on the tape can be read either by man or by an appropriate reading machine.
  • each of the electrodes substantially prolongs the operating life of the recording head because the tungsten is able to withstand the high temperatures developed by the electrical discharge.
  • the provision of two separate pin electrodes disposed close together tends to inhibit lateral drifting of the electrical discharge across the gap and thereby maintains the recorded information more truly on line in each recording channel on the tape.
  • the provision of a quartz separator between the pin electrodes as an insulating material also tends to prolong the life of the recording head.
  • the quartz has a high dielectric constant and is able to withstand the high temperatures developed by the electrical discharge and in addition is non-water absorbent, and thereby resists break-down or shorting out between the electrodes other than across the discharge gap.
  • an electrostatic recording head the combination of a pair of pin electrodes for each recording channel, a high voltage pulse circuit for providing negative high voltage pulses to one of said electrodes, and a current limiting resistor connected in series between the other of said electrodes and ground.
  • an electrostatic recording head for recording a plurality of code channels on a recording medium, the combination of a pair of high melting point pin electrodes disposed parallel to each other and each having a free end adjacent the recording medium, a high voltage pulse circuit for providing negative high voltage pulses to one of said electrodes, and a current limiting resistor connected in series between the other of said electrodes and ground.
  • An electrostatic recording head as defined in claim 2 melting point non-hygroscopic insulating material separating the pin electrodes, a pulse circuit connected to supply current to one of said electrodes, and a current limiting resistor connected in series with the other of said electrodes.
  • a device for recording electrostatic signals on a medium having a high surface resistivity the combination of a plurality of high voltage pin electrodes disposed in a parallel array each having a free end adjacent the recording medium, a plurality of ground electrodes also disposed in a parallel array with each having a free end adjacent the recording medium and with one such electrode disposed in close proximity with each of said high voltage electrodes, and a thin layer of non-hygroscopic insulating material having a high dielectric constant and a high melting temperature separating the high voltage electrodes from said ground electrodes, the free ends of each pair of electrodes defining an electrical discharge gap where ionized particles are generated to be deposited on the recording medium.
  • an electrostatic recording head for recording electrical signals on a moving paper tape having a plastic layer of high surface resistivity and an underlying layer which is electrically conductive and normally retained at ground potential

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Theoretical Computer Science (AREA)
  • Printers Or Recording Devices Using Electromagnetic And Radiation Means (AREA)
  • Recording Measured Values (AREA)
US3124804D 1961-10-16 Electrostatic recording head Expired - Lifetime US3124804A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US14537361A 1961-10-16 1961-10-16

Publications (1)

Publication Number Publication Date
US3124804A true US3124804A (en) 1964-03-10

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ID=22512809

Family Applications (2)

Application Number Title Priority Date Filing Date
US26212D Expired USRE26212E (en) 1961-10-16 Electrostatic recording head
US3124804D Expired - Lifetime US3124804A (en) 1961-10-16 Electrostatic recording head

Family Applications Before (1)

Application Number Title Priority Date Filing Date
US26212D Expired USRE26212E (en) 1961-10-16 Electrostatic recording head

Country Status (4)

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US (2) US3124804A (de)
DE (2) DE1913852U (de)
GB (1) GB981760A (de)
SE (1) SE311379B (de)

Cited By (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3335322A (en) * 1966-05-06 1967-08-08 Borg Warner Charge head array for electrostatic printing system
US3372400A (en) * 1962-12-03 1968-03-05 Borg Warner Electrostatic recorder with plural electrodes and biased mask
US3693185A (en) * 1970-10-15 1972-09-19 Versatec Electrostatic recording head
US4087826A (en) * 1976-08-02 1978-05-02 Epp Corp. Pulsed electrical printer with dielectrically isolated electrode
US4315270A (en) * 1978-06-01 1982-02-09 Xerox Corporation Backup electrode for an electrostatic recorder
FR2501443A1 (fr) * 1981-03-06 1982-09-10 Cit Alcatel Tete d'impression d'image
US5132705A (en) * 1988-12-06 1992-07-21 Ngk Insulators, Ltd. Recording head including electrode supporting substrate having thin-walled contact end portion
US5184344A (en) * 1989-08-21 1993-02-02 Ngk Insulators, Ltd. Recording head including electrode supporting substrate having thin-walled contact end portion, and substrate-reinforcing layer
US5231422A (en) * 1990-05-16 1993-07-27 Ngk Insulators, Ltd. Recording head having two substrates superposed such that electrode supporting surface of one of the substrates faces non-electrode-supporting surface of the other substrate

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3576585A (en) * 1968-10-24 1971-04-27 Toho Denki Co Ltd Scanning and recording device for electrostatic recording
GB1264743A (de) * 1969-04-15 1972-02-23

Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3076968A (en) * 1957-09-12 1963-02-05 Xerox Corp Electrostatically recording plurality of signal bits simultaneously

Patent Citations (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3076968A (en) * 1957-09-12 1963-02-05 Xerox Corp Electrostatically recording plurality of signal bits simultaneously

Cited By (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3372400A (en) * 1962-12-03 1968-03-05 Borg Warner Electrostatic recorder with plural electrodes and biased mask
US3335322A (en) * 1966-05-06 1967-08-08 Borg Warner Charge head array for electrostatic printing system
US3693185A (en) * 1970-10-15 1972-09-19 Versatec Electrostatic recording head
US4087826A (en) * 1976-08-02 1978-05-02 Epp Corp. Pulsed electrical printer with dielectrically isolated electrode
US4315270A (en) * 1978-06-01 1982-02-09 Xerox Corporation Backup electrode for an electrostatic recorder
FR2501443A1 (fr) * 1981-03-06 1982-09-10 Cit Alcatel Tete d'impression d'image
EP0059920A1 (de) * 1981-03-06 1982-09-15 COMPAGNIE INDUSTRIELLE DES TELECOMMUNICATIONS CIT-ALCATEL S.A. dite: Bilddruckkopf
US5132705A (en) * 1988-12-06 1992-07-21 Ngk Insulators, Ltd. Recording head including electrode supporting substrate having thin-walled contact end portion
US5184344A (en) * 1989-08-21 1993-02-02 Ngk Insulators, Ltd. Recording head including electrode supporting substrate having thin-walled contact end portion, and substrate-reinforcing layer
US5231422A (en) * 1990-05-16 1993-07-27 Ngk Insulators, Ltd. Recording head having two substrates superposed such that electrode supporting surface of one of the substrates faces non-electrode-supporting surface of the other substrate

Also Published As

Publication number Publication date
USRE26212E (en) 1967-05-30
GB981760A (en) 1965-01-27
SE311379B (de) 1969-06-09
DE1250141B (de)
DE1913852U (de) 1965-04-15

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