| 摘要 |
PURPOSE:To prevent a permanent set of a lift arm, a spring or the like from being generated, by providing a first cam for pressing the lift arm away from a platen and a second cam for pressing the spring to increase the deflection quantity of the spring, in rotatable conditions. CONSTITUTION:When in use, a lever 16 is released from a first cam 18, and a leaf spring 20 is pressed by a second cam 24. Under this condition, a lift arm 10 is turned downward with a support shat 3 as a fulcrum by the force of the spring 20, and a pinch roller 14 presses a paper 19 against a feeding roller 4. The lift arm 10 is stabilized at this position, and a gap between the paper 19 and a dot printer head 12 is determined. When not in use, a cam shaft 22 is rotated 180 deg., the leaf spring 20 is restored to a free condition under its own elasticity, and a cam shaft 6 is rotated 180 deg., whereby the lever 16 is pressed clockwise by the first cam 18, a shaft 9 is pushed upward by a base 15 of the lever 16, and the lift arm 10 is turned upward with the support shaft 3 as a fulcrum, thereby separating the pinch roller 14 from the feeding roller 4. |
