| 摘要 |
PURPOSE:To omit the supply of an electric current for holding a shifted condition and thereby reduce current consumption, by a construction wherein action of a rotating force on a positive motion cam is eliminated in a condition wherein a ribbon is shifted. CONSTITUTION:A ribbon guide shift lever 41 is turnably supported on a support shaft 26 protruding on left and right sides of a carrier 21, and a tip part 41a thereof shifts a ribbon guide 22 in the vertical direction. A rear end part 41b of the lever 41 is engaged to a guide member 45 through an engaging roller 44 by a support shaft 43. A cam roller 46 provided at the rear end of a cam follower 30b of a ribbon cassette base 30 is rollably fitted in a guide groove 47-3 of the positive motion cam 47. A cam surface at each rotational angle of the cam 47 corresponding to each shift position of a multicolor ink ribbon 33 (the position at which an ink band of the ribbon is positioned at a printing position) is made to be a flat surface substantially perpendicular to a line of action which passes through the center C of rotation of the cam 47, whereby the action of a rotating force on the cam 47 in the shifted condition of the ribbon can be eliminated, and the supply of an electric current for holding the shifted condition can be omitted. |
