The influence of electroless plated chromium on printing properties of aluminium offset printing plate

Abstract

A method for the improvement of the printing properties of offset printing forms is presented. Specimens of technical aluminum were electrochemically roughened and treated in different alkaline solutions of chromium chloride in order to chemically deposit a chromium layer. The composition of the surface layer was investigated by EDAX. Chromium was found on the specimens that had been treated in an alkaline solution of chromium chloride, while no chromium was found on chemically untreated specimens or on specimens that had been treated in an alkaline solution without chromium chloride. The spectral reflectance from treated and non-treated specimens was also measured. The chromium-treated specimens were brighter than the non-chromium-treated ones. The wettability of the chromium- treated samples was compared with the wettability of the non-chromium treated samples by measuring the contact angle with water and the wetted area. The chromium-treated samples showed increased wettability compared with the non-chromium-treated samples.A printing test was performed under real printing conditions. Control prints was analyzed densitometrically and statistically. The chromium-treated printing forms gave clearer prints than the non-chromium-treated printing forms under all printing conditions.

Keywords

• aluminum
• chromium
• electroless deposition
• printing plates.