| 摘要 |
<p>Xerographic image transfer agent consists of (a) a particulate component which deposits on a charged surface under the influence of electrotastic forces and (b) a second particulate component which deviates strongly w.r.t. the image transfer capacity of component (a). The second component may differ from the first e.g. in electrostatic activity, ink retention capacity, colour,light reflectance, light transmittance, or heat fixing properties. A pref. compsn. is a 5:1 mixt. of carbon and tal. The toners can be used in standard office xerographic copying machines. When the latent electrostatic image is developed with the powder mixts., component (a) deposits in the areas of high charge, whilst in areas of weak charge component (b) predominates. When the image is transferred in the usual way to a substrate material such as paper or an offset printing master, the powder mixt. gives areas ranging from black through grey to white, and thus gives a vastly improved half tone effect compared to normal xerographic toners.</p> |
