PRESSURIZING-TYPE WRITING UTENSIL

PROBLEM TO BE SOLVED: To provide a pressurizing-type writing utensil enabling applying pressurizing force to the rear end of a writing utensil ink composition only during handwriting.SOLUTION: A pressurizing type writing utensil is configured such that: an outer diameter of an ink housing cylinder 9, an outer diameter of a cylinder 8, and an outer diameter of a piston 16 are almost the same; a diameter-reduced front end part (front end periphery 8a) of the cylinder is attached into a rear end opening part of the ink housing cylinder, and a front part of the piston is attached to the rear end opening part; a ballpoint pen refill is moved backward in a state that the front end part of a ballpoint pen chip 12 projects from the front end of a barrel, and a rear end part of the piston abuts on a barrel inside to suppress the moving backward; the cylinder moves in a rear end direction of the barrel against the resilient force of a first resilient body (pressurizing coil spring 18) so as to close an air hole 8g of the cylinder by a sealing member (O-ring 17); and when the cylinder moves in a rear end direction of the barrel, a pressurizing space 8h between the cylinder and the piston is compressed to apply pressure to a rear end of a writing utensil ink composition 10.SELECTED DRAWING: Figure 1 【課題】筆跡時にのみ、筆記具用インキ組成物の後端に加圧力が加えることができる加圧式筆記具を提供する。【解決手段】インキ収容筒９の外径と、シリンダー８の外径、ピストン１６の外径を略同一とし、インキ収容筒の後端開口部内に、シリンダーの縮径された前端部（前端外周部８ａ）、後端開口部にピストンの前部が装着され、ボールペンチップ１２の前端部が軸筒の前端から突出した状態で、ボールペンレフィルを後方に移動させ、ピストンの後端部が、軸筒内に当接して後方への移動が抑制され、且つ第一弾発体（加圧用コイルスプリング１８）の弾発力に抗して、シリンダーが軸筒の後端方向に移動し、密閉部材（Ｏリング１７）によりシリンダーの空気孔８ｇを閉鎖させ、さらにシリンダーが軸筒の後端方向に移動すると、シリンダーとピストンとの加圧空間８ｈが圧縮されて、筆記具用インキ組成物１０の後端に圧力を加える。【選択図】図１