| 摘要 |
The thread is printed with magnetic ink patches 28,30,32 in parallel with visually-readable characters 14,16,18 formed in an aluminium coating 34 on a polyester film substrate 36. The visually-readable characters are formed by negative printing with a resist followed by etching. The magnetic ink patches may be impressed into the polyester substrate to provide a smooth upper surface. The magnetic patches are obscured by over-printing with a ribbon of silver or silver-coloured ink. The thread is then provided with a protective coating. |
