| 摘要 |
<p>Apparatus for implementing the tabulating function on a typewriter or communications printer terminal. An opaque cylinder is provided which rotates in synchronism with the relative movement between the printing mechanism and the recording medium. The cylinder wall is perforated with a series of holes along a line of rotation and sliding shutters in the cylinder wall may be selectively displaced to either block a hole or allow the passage of light therethrough. The holes correspond to character spaces, or print columns. A light source and a phototransducer are aligned so that when a hole is clear, the phototransducer produces a signal in response to light impinging thereon from the light source. The shutters are displaceable by two hammers, one on each side of the cylinder. One of the hammers displaces the shutters into the "tab clear" position and the other hammer displaces the shutters into the "tab set" position. Receipt of a "tab" signal causes the apparatus to search for a hole which has its associated shutter displaced to the "tab set" position.</p> |
