基于纸张表面结构的静电色粉传递特性分析

针对双组分固体色粉静电印刷复制过程中呈现新闻纸印刷网点扩大值小于铜版纸印刷网点扩大值的异常现象。笔者选取6种粗糙度不同的纸张,比较其印刷网点的扩大情况,并获取各样张半色调网点的SEM图,以分析静电印刷过程中色粉的传递特性。结果表明:固体色粉属性和纸张表面结构对静电印刷复制属性具有直接影响,色粉颗粒越小,其网点扩大越大; 新闻纸等粗糙度较大的纸张,其孔隙容纳了部分色粉颗粒,降低了熔融扩展程度,从而抑制了网点扩大; 且网点扩大越小,印品的成膜性与光泽度也相应降低。模拟色粉颗粒的热熔、扩展、附着的形态变化,直观表达了色粉传递与纸张平滑度的相关性,合理解析了静电印刷固体色粉传递中的网点扩大机理,为提高静电印刷质量提供理论依据。
In two-component toner solid electrostatic printing copying process, it always presented an abnormal phenomenon that the newsprint paper printing dot gain value is lower than the copperplate printing dot gain value. The situation of replication effect is that the higher the paper surface smoothness is, the more serious the dot gain becomes. This is contrary to the conventional dot gain in printing process. In order to explore the transmission characteristics of solid toner in electrostatic printing process, we selected six kinds of different roughness paper as substrate in the experiment, then measured the dot gain of CMYK color, and got the SEM micrographs of each sample. The results showed that the solid toner attributes and paper surface structure all had a direct effect on the electrostatic printing reproduction. The smaller the toner particles were, the greater the dot gain would be. When the roughness of paper is larger enough, such as newsprint paper, the pore part of paper will contain toner particles, so that can reduce the melting expansion of toner and inhibit the dot gain. In addition, when the value of the dot gain was smaller, then the film forming properties of ink and glossiness of print would decrease. By establishing the fusing model of solid toner, it explained the correlation of the toner transfer and paper smoothness, and analyzed the dot gain mechanism of solid toner transfer in electrostatic printing. The results of this study will provide a theoretical basis for improving the quality electrostatic printing in aspects of the research and development of high quality electrostatic printing-use paper and the development of solid toner technique