Microscopic Method for Determining the Size of Toner Particles in Page Substitution and Document Dating Cases

Toner is typically a powder that is used in laser printers and photocopiers to form printed text and images on paper. During the printing process, toner particles are partially melted by the heat of the fuser, binding them to one another and onto the paper. This paper describes a microscopic method for determining the average particle size of the toner used to produce a printed (copied) document. The method can assist forensic document analysts in page substitution cases, as well as in document dating cases in which it is necessary to establish whether the toner was available on the date that the contested document bears.