| 摘要 |
<p>A rotatable assembly includes a plurality of writing devices which are selectably moveable into and out of writing position. As the assembly rotates, the writing devices in the writing position describe concentric patterns on a recording medium. The selective movement of the writing devices may be controlled by an array of sensing elements such as light sensors. These may be located on the assembly and may be selectively energized, as the assembly rotates, in response to a smaller stationary group of energy emitting elements located next to the assembly.</p> |
