A Study on Mono-Component Color Developers for Electrophotography

近年来，电子照相被广泛应用于各种非接触式打印系统，如复印机、激光打印机、LED打印机等。虽然目前系统中主要使用双组件显影剂，但更希望使用单组件显影剂来提高其维护性。由于单组分显影剂中通常含有磁性材料，因此制作彩色单组分显影剂是很困难的。我们研究了非磁性单组分显影剂所必须具备的基本性质和条件。首先研究了聚苯乙烯、环氧树脂、聚乙烯等几种聚合物粉末的电学性能，它们可能是单组分显影剂的主要成分。研究发现，聚乙烯醇、聚氯乙烯、尼龙等聚合物不能长时间保持电荷。而聚合物粉末如聚乙烯、环氧树脂、聚四氟乙烯等可以保持电荷数天以上。其次，对由聚合物和颜料组成的粉末的电学性能进行了表征。这些粉末中的摩擦电荷量在1-10微克/克之间。这些粉末的电性能与主要抛光剂相似，例如，由聚氯乙烯和颜料组成的粉末不能长时间保持电荷。认为聚乙烯、环氧树脂等可能是单组分显影剂的主要聚合物。

Recently electrophotography is widely applied for various non-impact printing systems, for example photo-copying machines, laser beam printers, LED printers, etc. Although two-component developers are mainly used in the systems at the present time, mono-component developer is more desirable to improve their maintenance. Scince a mono-component developer usually contains magnetic materials, however, it is difficult to make color mono-component developers.We have studied fundamental properties and conitions which non-magnetic monocomponent developers must have. First electrical properties of several kinds of polymer powders, such as polystylene, epoxy, polyethylene, etc. were studied, which may be the main constituent of the mono-component developers. It was found that polymers, such as polyvinyl alcohol, polyvinyl chloride, nylon, could not keep charge for a long time. While, polymer powders, such as polyethylene, epoxy, Teflon, etc. could keep charge for more than several days.Next, electrical properties of the powders, consisting of a polymer and a pigment, were characterized. The amounts of tribo charge in those powders were in the range og 1 - 10 <micrn>C/g. Electrical properties of the pwders are similar to those of the main polmers, for example, the pwder, consisting of polyvinyl chloride and a pigment, cannot keep charge for a long time. It is concluded that polyethylene, epoxy, etc. may be the main polymer for mono-component developers.