| 摘要 |
The device has an external envelope (1) surrounding a needle (2) over part of its length, such that the pointed end (5) of the needle protrudes by a predetermined length. The open end (6) of the envelope thus forms a depth stop for the needle. The needle is securely fastened inside the envelope. A small gap is maintained between the needle and the internal wall of the envelope to receive a quantity of ink or other colouring material. The wall of the envelope includes at least one opening (7). |
