| 摘要 |
<p>A particulate developer for developing a latent electrostatic image on a substrate, at least comprising electrostatically charged particles of a synthetic compsn., is a colourless developer which can be added, in pre-determined amt., to a coloured developer, to lower the final colour density of the developed image to a required value. The colourless developer pref. contains a transparent synthetic resin, esp. polyvinylpyrrolidone, polyvinyl acetate, polymethyl methacrylate, polystyrene, a polyester or PVC. It may contain an uncoloured pigment, esp. a white pigment, e.g. TiO2, Al2O3, ZnO or MgO. The synthetic compsn. is dispersed in an electrically insulating liq., partic. an unbranched hydrocarbon. The compsn. may contain an agent for controlling the charge, e.g. a metal soap. A particulate developer compsn. comprising a mixt. of a coloured particulate developer and an uncoloured particulate developer is claimed.</p> |
