| 摘要 |
PURPOSE:To prevent generation of an erroneous mark by providing a sensor which checks laser beam passing through light transmission perforations opened on each rotary stencil only when each rotary stencil stops at an exact position on the side of a material to be marked of a multiple rotary stencil. CONSTITUTION:Many light transmission perforations 9 are opened on a circle of the same diameter from a center at fixed minimum stencil rotary angular intervals, on three rotary stencils 4a to 4c. First, each rotary stencil 4a to 4c of a multiple rotary stencil 4 is driven by a stepping motor individually to select characters. Then laser beam L begins to be oscillated, and the beam L reaches the multiple rotary stencil through a mirror 2, and a cylindrical lens 3. If rotary stencils 4a to 4c are set correctly, part of the beam L passes through light transmission perforations 9 and enters in a sensor 5. Thus it is checked whether the position of the rotary stencils 4a to 4c are correct. If the sensor 5 does not react, then oscillation of the laser beam is stopped. |
