Ink Drying Tester - OpTest

Drying property of letterpress or lithography ink is evaluated, by measuring the time till the ink dries and it is not transferred to the paper even if it is pressed against the paper. Gravure ink or other inks that are dried by heating or another process cannot be used on this tester. Test principle: a printing specimen and a counter-paper-sheet are overlapped and wound around the drum rotating at a constant speed; upon them, a press gear that applies a constant load is put, and it is moved along with rotation of the drum. From the trace of the press gear on the counter-paper-sheet, the drying time and set-off of the specimen are measured.