A writing tip assembly for dispensing a free-flowing low-viscosity ink from a writing instrument may include a micro-spring, a writing ball configured to transfer ink to a substrate, and a second ball between the writing ball and the micro-spring. The second ball is configured to transfer ink to the writing ball. A writing instrument for dispensing a free-flowing low-viscosity ink includes an ink reservoir, the writing tip assembly, and a feeder fluidically coupling the ink reservoir to the writing tip assembly.

A writing tip assembly for dispensing a free-flowing low-viscosity ink from a writing instrument may include a micro-spring, a writing ball configured to transfer ink to a substrate, and a second ball between the writing ball and the micro-spring. The second ball is configured to transfer ink to the writing ball. A writing instrument for dispensing a free-flowing low-viscosity ink includes an ink reservoir, the writing tip assembly, and a feeder fluidically coupling the ink reservoir to the writing tip assembly.

A pen includes: an ink reservoir configured to store an ink; and a pen tip section including an ink application part configured to apply the ink to an ink application object. The ink application part of the pen tip section includes: a rigid tip made of a rigid material and having a hemispherical outer surface, an inner surface facing toward the ink reservoir, and a penetration part penetrating from the inner surface side to the outer surface side of the rigid tip; and at least one foam body filled in the penetration part at least on the side of the penetration part close to the outer surface side of the rigid tip, and provided with at least one air bubble formed to communicate from the outer surface side of the foam body to the inner surface side of the foam body.

A pen includes: an ink reservoir configured to store an ink; and a pen tip section including an ink application part configured to apply the ink to an ink application object. The ink application part of the pen tip section includes: a rigid tip made of a rigid material and having a hemispherical outer surface, an inner surface facing toward the ink reservoir, and a penetration part penetrating from the inner surface side to the outer surface side of the rigid tip; and at least one foam body filled in the penetration part at least on the side of the penetration part close to the outer surface side of the rigid tip, and provided with at least one air bubble formed to communicate from the outer surface side of the foam body to the inner surface side of the foam body.

A writing instrument comprises a hollow body having a first end and a second opposite end along a longitudinal axis (X); a deformable tank inside the hollow body and containing ink; a writing tip disposed at the first end of the hollow body and in fluid communication with the deformable tank; and a deformation device configured to squeeze the deformable tank along the longitudinal axis (X) so as to move forward towards the writing tip the ink contained in the deformable tank.

A ball point tip comprising a ball holder having an ink conduit and a ball house, a ball accommodated into the ball house and a leaf spring axially disposed between the ball and an axial end of the ink conduit, the leaf spring having a main body and a plurality of tongues extending radially from the main body, ink passages being formed between the tongues in order to fluidly connect the ink conduit and the ball house, wherein the ball holder and the leaf spring are made of plastic and unitary formed.

A ball point tip comprising a ball holder having an ink conduit and a ball house, a ball accommodated into the ball house and a leaf spring axially disposed between the ball and an axial end of the ink conduit, the leaf spring having a main body and a plurality of tongues extending radially from the main body, ink passages being formed between the tongues in order to fluidly connect the ink conduit and the ball house, wherein the ball holder and the leaf spring are made of plastic and unitary formed.

A ballpoint pen is disclosed. In the ballpoint pen, an oil-based ballpoint pen ink composition has an ink viscosity with a range of 500 mPa.Math.s to 15000 mPa.Math.s inclusive at 20° C. and a shear rate of 500 sec.sup.-1. A ball has a ball diameter of 0.5 mm or less. A tip distal end portion includes a first swaged portion and a second swaged portion. The first swaged portion has an inclination angle with a range of 90 degrees to 100 degrees inclusive. The second swaged portion is provided closer to a distal end side of a ballpoint pen tip than the first swaged portion and has an inclination angle with a range of 110 degrees to 130 degrees inclusive. An angle of a bottom wall of a ball holding chamber is the same as the inclination angle of the second swaged portion.

A ballpoint pen is disclosed. In the ballpoint pen, an oil-based ballpoint pen ink composition has an ink viscosity with a range of 500 mPa.Math.s to 15000 mPa.Math.s inclusive at 20° C. and a shear rate of 500 sec.sup.-1. A ball has a ball diameter of 0.5 mm or less. A tip distal end portion includes a first swaged portion and a second swaged portion. The first swaged portion has an inclination angle with a range of 90 degrees to 100 degrees inclusive. The second swaged portion is provided closer to a distal end side of a ballpoint pen tip than the first swaged portion and has an inclination angle with a range of 110 degrees to 130 degrees inclusive. An angle of a bottom wall of a ball holding chamber is the same as the inclination angle of the second swaged portion.

Disclosed are a knock type direct liquid pen refill assembly and a writing pen. The pen refill assembly comprises an ink cylinder assembly (100), a pen tip (200) and an elastic member (300). An ink guide core (150) is provided in the ink cylinder assembly. The pen tip (200) is arranged at one end of the ink cylinder assembly (100). An ink duct (210) is formed inside and passes through the pen tip (200). A ball member (230) is provided at an ink outlet end of the ink duct (210). The ink guide core (150) partially passes through the ink duct (210), and one end of the ink guide core (150) is abutted against the ball member (230). The elastic member (300) is sleeved at the periphery of the ink guide core (150) and positioned inside the ink duct (210). The elastic member is abutted against the ball member to exert a force, such that the ball member is closely attached to an inner wall of the ink outlet end, the ball member forms sealed contact with the inner wall of the ink outlet, and ink volatilization and leakage are avoided.