JPS57198262A - Multiple liquid type etching method in gravure engraving - Google Patents

Abstract

PURPOSE:To make the manufacture of a machine plate of stable quality with good reproducibility without requiring skill by measuring the penetration time of resist by inspecting liquid, and determining etching conditions prior to corrosion. CONSTITUTION:When conductive inspecting liquid SL is dropped onto the resist electrode 12, 14 positions on resist 10, these contact, and from the point when they drop, potential VB from an electric power source VCC enters a comparator 16. Since this is larger than threshold potential VTH, a counter 22 begins to move, and the liquid SL penetrates through the resist and therefore the VB decreases gradually and stops decreasing at the point when it goes lower than the VTH, from which the penetration time (t) can be measured. This is determined with respect to gradation partsI-IV. The relation between cell setting volume V and the time t is determined from the relation between the volume V and positive concn. and the time (t), and the relation between the time and etching liquid penetration time. The combinations of various etching liquids to be used, the use sequence thereof and the time distribution of the use can be derived by utilizing the curves thereof. The etching of the plate material entails the determination of a total corrosion time and this is determined from about at least how mutch time T is required in order to obtain the volume V of the extreme shadow part IV.