Determination of crossing sequences between seal impression and laser‐printed lines based on characteristics of the toner molten state

Abstract

Determining the sequence of intersection lines is a challenge in forensic document examination. To explore more advanced technology and meet the needs of practical applications, this study proposes a method based on the characteristics of the molten state to examine crossing-line sequences. This state can be considered as a melting state of solid laser toner through a dissolution process. Experimental results demonstrate that the molten state is always visible at intersections when a particular ink is stamped after laser printing; however, the presence of the molten state when the seal is stamped before laser printing largely depends on the time interval between printing and stamping. The degree of error obtained through blind tests indicates that this approach has its limitations; however, a high accuracy, which refers to the ability of an examiner, was achieved with respect to determining the sequence of strokes when using a fluorescence method in conjunction with this method. This further indicated the limitation of a single method and the importance of combining multiple methods for document examinations.

Systematic study of a method to determine the sequence of crossing lines on stamping before writing

“…Beyond the vermilion inkpad, five other stamp pad inks were chosen based on market prevalence: foam inkpad, water-based stamp pad ink (composed of dyes, resins, organic solvents, and water), oil-based stamp pad ink (composed of oily pigments, resins, and organic solvents), atomic stamp ink pads, and photosensitive stamp ink pads. The atomic and photosensitive stamp ink pads are specially formulated inks stored in self-ink storage within the seal, stamped from holes in the seal during the sealing action [12]. Table 2 lists the six types of stamp seal inks.…”

Interpol questioned documents review 2019–2022

“…including any other technology used to prepare the document. The following 64 articles [ [548] , [549] , [550] , [551] , [552] , [553] , [554] , [555] , [556] , [557] , [558] , [559] , [560] , [561] , [562] , [563] , [564] , [565] , [566] , [567] , [568] , [569] , [570] , [571] , [572] , [573] , [574] , [575] , [576] , [577] , [578] , [579] , [580] ] [ [581] , [582] , [583] , [584] , [585] , [586] , [587] , [588] , [589] , [590] , [591] , [592] , [593] , [594] , [595] , [596] , [597] , [598] , [599] , [600] , [601] , [602] , [603] , [604] , [605] , [606] , [607] , [608] , [609] , [610] , [611] ], combined with 17 presentations [...…”

“…Wu et al used laser fluorescence microscopy to study the intersections between stamp ink impressions and toner printing [ 553 ]. And in 2021, another study of stamp ink impressions and laser-printed lines focused on the characteristics of the toner fusing characteristics [ 554 ]. Wu et al [ 555 ] studied the use of coaxial lighting to view the sequence of line crossings between electrophotographic processes (toner) and writing inks.…”