| 摘要 |
PROBLEM TO BE SOLVED: To provide a water base ink ballpoint pen for writing a handwriting having a predetermined thickness always with constant head of ink irrespective of an ink amount in an ink tank. SOLUTION: In the water base ink ballpoint pen comprising a ball 4 rotatably held in the state that the ball 3 partly oppositely projects from an end opening of a tip 3 and the tip 3 mounted at an end of an ink tank 1 filling water base ink, a tail end face of the tank 1 is closed to form a closed space. And, a tail end opening 2a communicates with the atmosphere. An internal pressure regulating tube 2 closed at its end 2b is disposed in the tank 1 so that its end is disposed near the tip 3, and a check valve 6 for invading the air into the tank 1 as the ink is consumed is disposed near an end of the tube 2. |
