Novel developing agents for (photo) thermographic systems
申请人:MINNESOTA MINING AND MANUFACTURING COMPANY
公开号:EP0681210A1
公开(公告)日:1995-11-08
A thermographic element comprising in a non-aqueous binder medium a silver salt oxidising agent in reactive association with a compound comprising a plurality of redox colour releasing moieties such that oxidation of each redox colour releasing moiety causes release from said compound of a thermally diffusible dye.
The compounds many of which are new incorporate two or more developer moieties into a single molecule to minimise the diffusibility of the compound. Following oxidation, either directly by the silver salt or by means of a cross-oxidising agent, each oxidised developer moiety releases a thermally diffusible dye. The compounds are of sufficient size and molecular weight to slow or prevent diffusion in imaging systems and yet possess several active developer moieties per molecule which is advantageous over known ballasted dye releasers which comprise bulky molecules with only a single developer moiety.