1. Field of the Invention
The present invention relates to printers having an arrangement for switching the ribbon guide among three positions, having two electromagnets each with an armature mounted on a pivoted armature lever which is in turn connected to the ribbon guide bar.
2. Prior Art
Printers such as teleprinters require switching of a one- or two-colored ribbon from a black or upper position into a red or lower position, usually by raising and lowering a ribbon guide carrying the ribbon. Also, to allow viewing of the printed matter, a further, so-called visibility position of the ribbon is necessary. Thus, the ribbon guide in a printer must be able to be switched into any of three positions.
It is known to provide a ribbon control system having two electromagnets. Magnetic armatures are each arranged on an armature lever which is in turn connected to the ribbon guide bar so that a movement of the armature levers is transmitted to the ribbon guide bar to move the bar upwardly or downwardly. The third position of the ribbon guide is obtained upon the absence of current in both electromagnets, when the ribbon guide assumes a central position between the upper and the lower position. A problem presented by these devices is in safely and assuredly maintaining the ribbon guide in this third, non-printing position.
USPTO Backgrounds
USPTO Backgrounds