Evaluation of the performance of erasable marker pen ink for the development of indentations on documents upon surface charging by electrostatic detection device

Abstract

Indented impressions can be left on the surface beneath a document when it is written on. In the absence of this document, electrostatic detection devices can be used to reveal the underneath previously written information. However, there are instances where the toner used to develop these indentations has to be substituted with alternative application, under unexpected circumstances, such as the supply chain disruption during the ongoing global pandemic. This study aimed to verify the use of erasable marker pen ink as an alternative application for the development of indentations. The procedure was optimized and evaluated, and its performance in deciphering indented impressions from 11 different underlying surfaces was compared to a conventional electrostatic detection device that applied toner to develop indentation. Electrostatic device with toner application using cascade developer method has successfully developed indented impressions from all surfaces, except for the coated glossy paper. In contrast, the application of erasable marker pens revealed indentation successfully from not only the coated glossy paper but also six other common writing surfaces. While the toner is a reliable application for deciphering indentations, the application of erasable marker ink pen can be used in the event when toners are unavailable but also on surfaces such as glossy paper, where application of toners to develop indentation may not provide satisfactory results.