Abstract: A supplementary study was conducted to investigate the deviation of baseline parallel, line spacing and page margins of added printed entries caused by mechanical errors. A new examination approach based on Photoshop was developed. It is concluded that deviation characteristics exist unavoidably on added printed documents, and the new approach is a convenient and effective way to find out addition.

Key words: addition of printed documents, printer, mechanical error, common characteristics, new examination method

摘要： 结合打印机工作原理,对打印机进纸、走纸机械构件不可避免的造成文书添加打印内容的图文字迹横轴线倾斜异常、行距异常、页边距异常该三方面共性特征的机械原理做出解构分析,对添加打印变造文书做出补充性的研究,进一步确证添加打印内容与原文书内容差异特征的客观存在。并介绍以photoshop图像处理软件为平台的更便捷、直观、高效的科学检验新方法,解决实际工作中运用以往机械比对方法难以实现添加打印变造文书检验目的情况。

关键词: 添加打印文书, 打印机, 机械误差规律, 共性特征, 检验新方法