| 摘要 |
Markings, esp. numbers, are applied to continuously conveyed packages by spraying three chemical substances in succession from three separate nozzles. The second and third substances each react with the first. The third is pref. sprayed through a template, thus producing markings against a contrasting background. Pref the first component is CuSO4 or PbCl2, the second component a light metal sulphide, and the third component a light soluble carbonate. |
