| 摘要 |
PROBLEM TO BE SOLVED: To provide a convenient duplex writing implement in which a ball- point pen using an ink which can be erased by an eraser, a mechanical pencil, etc., are combined according to specifications and which has an eraser feeding mechanism at its rear end. SOLUTION: The writing implement is composed of a cylindrical cam 34 for advancing a writing body selectively by pushing the rear end of one of sliding pieces and an eraser holder which holds the eraser 56 and can slide in the axial direction along the slit of an inner cylinder. In the ball-point pen, a tip ball is always pushed to be contacted with the inner fringe of a ball holding part at the tip of a chip. In an ink housing tube, a water base ink having viscosity reduced by shear, a low viscosity oily ink, or an ink in which a crosslinking substance is added into an ink solvent so that the ink is solated by the rotation of the tip ball associated with writing and gelated in a depicting state to be prevented from penetrating into paper to be erasable by an eraser is packed, and a greaselike follower 19 which is moved to follow the consumption of ink is packed in the rear end of the ink.
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