Electrode apparatus for a printer for electrostatic matrix printing
United States Patent Krekow et al.  
 ELECTRODE APPARATUS FOR A PRINTER FOR ELECTROSTATIC MATRIX PRINTING Inventors: Gerhard Krekow, Schenefeld; Klaus Witter, Hamburg; Jurgen Schramm, Norderstedt, all of Germany Assignee: U.S. Philips Corporation, New  
 York, NY.  
 Filed: Oct. 29, 1973 Appl. N0.: 410,977  
 Foreign Application Priority Data Nov. 2, 1972 Germany 2253625 US. Cl. 346/74 ES; 346/74 S Int. Cl. G0ld 15/06; B41j 3/10 Field of Search 346/74 E. 74 ES, 74 CH,  
 346/74 S, 74 SB, 74 SC, 139 C Primary E.\&#39;aminer--Bernard Konick Assistant E.ranziner-Jay P. Lucas Attorney, Agent, or FirmFrank R. Trifari [57] ABSTRACT A printer for electrostatic matrix printing, comprising a counter electrode, a space for a record carrier, a ceramic body with openings, and an electrode system consisting of conductor tracks between which spark gaps are formed which are situated in the prolongation ,of the openings.  
 3 Claims, 2 Drawing Figures ELECTRODE APPARATUS FOR A PRINTER FOR ELECTROSTATIC MATRIX PRINTING The invention relates to a printer for electrostatic matrix printing, comprising a space for a record carrier, the said space being situated between a counter electrode and an electrode system which consists of image electrodes which are insulated with respect to each other, a ceramic body being arranged on the side of the electrode system which faces the said space. the said ceramic body being provided with openings extending perpendicular to the record carrier.  
  Electrode arrangements of this kind serve for the formation of electrostatic charge image points. The prior art describes an electrode arrangement in which an electrode system is incorporated comprising electrodes which are arranged one above the other and which are insulated from each other, at least the electrode facing the space for the record carrier being provided with a bore extending perpendicular to the record carrier such that an air gap is produced between the electrodes.  
  The invention has for its object to simplify the construction of such electrode arrangements.  
  This object is achieved according to the invention in that the electrode system is formed by conductor tracks, a narrow gap being present between the end face of a conductor track and the end face of a neighbouring conductor track, the said gap constituting a spark gap, each spark gap being situated in an envelope defined by a projection of the openings.  
  In the manufacture of conductor tracks according to a thick-film technique while using materials such as, for example,tungsten and ceramics, a very long service life of, for example, 10 discharges is obtained. A further advantage is that the connection of the electrodes can be very simply realized by way of plug-type connectors.  
  One embodiment according to the invention is shown in the drawing.  
  FIG. 1 is a perspective view of the mechanical construction of an electrode system for a printer according to the invention, and FIG. 2 is a cross-sectional view with an electrical circuit diagram.  
  As is shown in FIG. 1, a large number of conductor tracks 3 and 4, preferably made of tungsten paste, are baked into two ceramic plates 1 and 2, for example, of A1 0 by the silk-screen printing technique. The two plates 1 and 2 are mounted such that between the end faces 5 and 6 of oppositely arranged conductor tracks an airgap 7 of approximately 30 to 50 micrometers exists. A single ceramic plate can alternatively be used on which a gap is, for example, ground between the corresponding conductor tracks. Electrodes which are oppositely arranged in pairs, for example 3&#39; and 4&#39;, constitute a spark gap 8. The two ceramic plates 1 and 2 are arranged on a ceramic plate 9 having a thickness of a few tenths of a millimetre (attachment not shown), the said plate 9 being provided with openings 10, the arrangement being such that each time a spark gap 8 is situated in the projection of an opening 10. The complete electrode system is situated at a distance of a few tenths of a millimeter (air gap L) from a record carrier 11 having a dielectric layer which itself is arranged on a plate-like counter electrode 12 (see FIG. 2).  
  As is shown in FIG. 2, for example, for the electrical operations one (3) of the two conductor tracks 3, 4 constituting a spark gap 8 receives a high voltage pulse U of approximately 1 to 1.5 kV, while the other conductor track (4) is grounded. As a result, a spark is produced between these conductor tracks. A pointlike charge image is produced on the record carrier 11 by applying a voltage pulse U,- (500 to 1000 volts of re versed polarity) to the counter electrode 12.  
 What is claimed is:  
  l. A printer for electrostatic matrix printing on an associated generally planar record carrier comprising: first and second image electrodes, a counter electrode in spaced relation to said image electrodes said image electrodes being electrically insulated with respect to each other. a ceramic body disposed intermediate&#39;said image electrodes in spaced relation to said counter electrode to permit movement of the record carrier therebetween, said body being provided with openings each having an axis extending perpendicular to the re: cord carrier, said image electrodes each comprising a plurality of conductor&#39; tracks extending away from a narrow elongated gap each of said conductor tracks having an end face abutting said gap, each of said conductor tracks in one image electrode being disposed proximate to a conductor track in the other image electrode to define a spark gap, each of said spark gaps being disposed within an envelope defined by a projection of one of said openings.  
  2. A printer as claimed in claim 1, characterized in that the conductor tracks are provided on a ceramic substrate by means of a thick-film technique.  
  3. The apparatus as described in claim 1 wherein each of said openings is cylindrical.  
  Patent No. 3 ,877 038 UNITED STATES PATENT OFFICE CERTIFICATE 6F -1=- RETIN Dated April 8, 1975 Inventor-(s) Gerhard Krekow? Klaus Witter, Jurgen Schramm It is certified that error appears in the above-identified patent hat said Letters Patentare hereby corrected as shown below:  
 &#34; Foreign Application Priority Data NOV. &#39;2, 1972 Germany r .2253625 should read Signed and sealed this 15th day of July 1975.  
 (SEAL) Attest:  
 RUTH C. MASON Attesting Officer C. MARSHALL DANN Commissioner of Patents and Trademarks UNITED STATES PATENT OFFICE CERTIFICATE OF QORREQTION Patent No. 3,877,038 Dated April 8, 1975 Inventofls) Gerhard Krakow; Klaus Witter Jurgen Schramm It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:  
  Foreign Application Priority Data Nov. 2, 1972 Germany ..2253625 should read -&#39;--Foreign Application Priority Data Nov. 2, 1972 Germany, .P2253625. 0&#34;  
 Signed and sealed this 15th day of July 1975.  
 (SEAL) Attest:  
  C. MARSHALL DANN RUTH C. MASON Commissioner of Patents Attesting Officer and Trademarks