Man Roland Druckmaschinen Ag

H. C. Starck, Gmbh & Co Kg

Falko Schlenkrich

Karlheinz Reichert

Lutz Seffner

Andreas Schonecker

Hans-Jurgen Gesemann

A ferroelectric ceramic material, for the storage of information in electrostatic printing processes, which ferroelectric ceramic material has a coercive force of less than 200 V/mm. The ferroelectric ceramic material consists of a ceramic perovskitic mixed crystal, which contains one or more components from each of Groups 1 and 2, whereby Group 1 contains the components PbTiO.sub.3, BaTiO.sub.3, Pb(Fe.sub.1/2 Nb.sub.1/2)O.sub.3 and Pb(Zn.sub.1/3 Nb.sub.2/3)O.sub.3 and Group 2 contains the components Pb(Mg.sub.1/3 Nb.sub.2/3)O.sub.3, Pb(Ni.sub.1/3 Nb.sub.2/3)O.sub.3, Pb(Fe.sub.2/3 W.sub.1/3)O.sub.3 and Pb(Mn.sub.1/2 Nb.sub.1/2)O.sub.3. The proportions of the components from the two groups in the mixed crystal are determined according to the following equation: ##EQU1## where X.sub.i is the mole fraction of the i-component, T.sub.ci is the Curie point of the i-component and T.sub.cM is the Curie point of the mixture between 50.degree. C. and 100.degree. C.

Printing cylinder having a ferroelectric ceramic material surface

Highly reactive metal niobates and/or metal tantalates of the general formula Me(II)A.sub.2 O.sub.6 or Me(III)AO.sub.4, a method for the preparation thereof, their further processing to form perovskites of the general formula X(B'B')O.sub.3 wherein X signifies Pb and/or Ba, B' signifies Mg, Fe, Co, Ni, Cr, Mn, Cd, Ti, Zr and/or Zn and B' signifies Nb and/or Ta, as well as these perovskites are provided through the present invention. An additive of Li, Na and/or K is provided to the niobates/tantalates in 0.1 to 20 mol-%.

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Dresden, Germany

Falko Schlenkrich