| 摘要 |
1348425 Etching; credit cards; printing processes; printing surfaces PITNEY-BOWES Inc 16 July 1971 [27 July 1970] 33574/71 Headings B6C B6J and B6A Etching; credit cards.-A sheet of plastics material such as polyvinyl chloride, e.g. a credit card, is etched to give one surface a matte finish by passing between rollers one of which dips into a bath of methyl ethyl ketone, and is then provided with one or more code marks not visible under light but visible under ultra-violet radiation by means of a marker material carried in a solvent which acts as an etchant to etch the surface in the code area and allow the material to be absorbed into the sheet. The solvent may be the same as the first etchant. The resulting card has an etched surface all over, so that the marks are not rendered visible by contrast with an untreated glossy surface area. Printing processes.-The marks visible under ultra-violet radiation but not under light are made by impinging against the plastics sheet 66 an absorbent member containing a printing- material consisting of 3-phenyl-7-(3-chloro-5- diethyl amino triazyl) coumarin, in a solvent such as methyl ethyl ketone or tetrahydrofuran, which acts on the sheet surface to allow penetration of the material. Printing - surfaces.-An absorbent printing block comprises an upper foam body 54 and a lower foam body 56 of higher density. The upper body stores the printing-material, which is drawn into the lower body by capillary action for transfer to the sheet 66 to be printed. |
