Knock type direct liquid pen refill assembly and writing pen

A knock type direct liquid pen refill assembly comprising:

• an ink cartridge assembly provided with an ink guide core therein;
• a pen tip disposed at one end of the ink cartridge assembly, in which an ink duct is formed and passes therethrough, a ball member is provided at an ink outlet end of the ink duct, the ink guide core is partially inserted into the ink duct and one end of the ink guide core abuts against the ball member;
• and
• an elastic member wrapped around the outer periphery of the ink guide core and positioned inside the ink duct, and the elastic member abuts against the ball member to exert a force to push the ball member up against the inner wall of the ink outlet end;
• wherein the elastic member is a conical spring and one end of the conical spring gradually tapers in diameter toward the ball member;
• wherein the ball member comprises an upper ball and a lower ball, wherein the upper ball abuts against the lower ball, the conical spring abuts against the upper ball and the ink guide core abuts against the upper ball;
• wherein the ink cartridge assembly comprises an ink cartridge, a regulator, a first connecting member and a second connecting member, in which the regulator is disposed in the ink cartridge, a first through hole is formed inside the regulator;
• the first connecting member comprises a hollow straight cylindrical portion having an outer lateral surface provided with a first convex ring portion along a circumferential direction thereof, the ink cartridge is sleeved on the outer lateral surface of the straight cylindrical portion, one end of the ink cartridge abuts against the first convex ring portion and one end of the regulator is inserted into the first connecting member;
• a second through hole is formed inside the second connecting member, and the outer lateral surface of the second connecting member is provided with a second convex ring portion and a third convex ring portion along a circumferential direction thereof;
• one end of the second connecting member is inserted into the first through hole and one end of the regulator abuts against the second convex ring portion and one end of the first connecting member abuts against the third convex ring portion;
• one end of the pen tip is inserted into the second through hole;
• and
• the first through hole, the second through hole and the ink duct are coaxial and communication with each other, and the ink guide core penetrates through the first through hole, the second through hole and the ink duct;
• wherein a vent is opened on the first connecting member;
• wherein the outer peripheral wall of the straight cylindrical portion of the first connecting member is provided with ventilation grooves along its circumferential direction;
• wherein one or more first protruding portions are provided on an inner peripheral wall of the ink duct;
• the first protruding portions are pressed up against the ink guide core;
• one or more second protruding portions are disposed on an inner peripheral wall of the second through hole;
• the second protruding portions are abutted against the ink guide core;
• the upper end of the ink guide core is in an interference fit with the first through hole.