Provided is a writing instrument suited to ballpoint pens, marking pens and the like in which a flow pressure of an ink applied to a pen tip is controlled to a fixed level to prevent an ink direct flow phenomenon reverse flow phenomenon. The above writing instrument comprises a pen tip disposed at a front part of an ink tank, an ink received in the ink tank, a follower filled at a rear part of the ink, and a capillary porous member provided with a capillary force, which is arranged at a space part between a rear part of the follower and a rear end part of the ink tank in a state in which the follower is filled, wherein the pen tip is sealed when a cap is put on the writing instrument.

A water-based ink composition is described. The water-based ink composition includes a latex containing styrene-butadiene rubber particles, and a coloring agent, the glass transition temperature of the styrene-butadiene rubber particles being 10 C. to 50 C.

A water-based ink composition is described. The water-based ink composition includes a latex containing styrene-butadiene rubber particles, and a coloring agent, the glass transition temperature of the styrene-butadiene rubber particles being 10 C. to 50 C.

Devices have a flexible housing with an inside chamber having a closed and open end. A first chemiluminescent fluid is disposed in a breakable container in the chamber, and a second chemiluminescent fluid is in the chamber. A tip assembly is attached to the housing and includes a nib movably disposed in the body, and a filter element may be positioned within the body to prevent passage of broken particles from the container to the nib tip. A resilient element is used to impose an outward biasing force on the nib. A porous material is disposed over an outer surface of the nib tip and securely held in place. The device is activated for use by bending the housing to break the container causing the first and second chemiluminescent fluids to mix and react, providing a chemiluminescent solution that flows to the tip assembly for dispensing onto a desired surface.

Provided is a writing instrument or an applicator using resin parts formed, by way of two-color molding, to have an optimal guiding clearance between slide members. A plurality of resin molded parts is included. At least one of the plurality of resin molded parts is formed as a primary molding, and at least another one of the resin molded parts is formed as a secondary molding, by way of two-color molding, using a portion of a surface of the primary molding. The primary molding and the secondary molding are separated to be used as independent members. In this case, the primary molding and the secondary molding are preferably configured to slide against each other by each separating portion.

Provided is a writing instrument or an applicator using resin parts formed, by way of two-color molding, to have an optimal guiding clearance between slide members. A plurality of resin molded parts is included. At least one of the plurality of resin molded parts is formed as a primary molding, and at least another one of the resin molded parts is formed as a secondary molding, by way of two-color molding, using a portion of a surface of the primary molding. The primary molding and the secondary molding are separated to be used as independent members. In this case, the primary molding and the secondary molding are preferably configured to slide against each other by each separating portion.

There is provided a friction body which is adapted to rub a thermochromic image or handwriting formed on a paper surface by use of thermochromic ink to thermally discolor the thermochromic image or handwriting by frictional heat resultant from rubbing, a thermal conductivity of a friction portion of the friction body is set to be within 0.05 W/(m.Math.K) to 50 W/(m.Math.K).

There is provided a friction body which is adapted to rub a thermochromic image or handwriting formed on a paper surface by use of thermochromic ink to thermally discolor the thermochromic image or handwriting by frictional heat resultant from rubbing, a thermal conductivity of a friction portion of the friction body is set to be within 0.05 W/(m.Math.K) to 50 W/(m.Math.K).

A waterproof paint formula and a pen device for using the same are disclosed. The concentration of the formula may be adjusted by changing the weight percentage of the aqueous solution and cooperate with different outlet diameter of the nibs to make the waterproof paint smoothly flow out for painting on the writings. Simultaneously, the weight percentage of Ethyl Alcohol may be adjusted to control the air-dried speed of the waterproof paint to achieve the effects of waterproof and preventing the inks or colors from diffusion.

A waterproof paint formula and a pen device for using the same are disclosed. The concentration of the formula may be adjusted by changing the weight percentage of the aqueous solution and cooperate with different outlet diameter of the nibs to make the waterproof paint smoothly flow out for painting on the writings. Simultaneously, the weight percentage of Ethyl Alcohol may be adjusted to control the air-dried speed of the waterproof paint to achieve the effects of waterproof and preventing the inks or colors from diffusion.