A writing instrument includes: a writing instrument body and an ink cartridge. The ink cartridge includes a bottomed cylindrical container with an opened front end and a plug fitted into an inner circumferential surface of an opening of the container. The writing instrument body includes a projection that opens the ink cartridge when inserted into the opening to press the plug rearward and an air tight connecting portion, formed separately from the projection, that surrounds the projection. The opening is divided into a plurality of openings by air tight fitting the opening in the air tight connecting portion. A plurality of longitudinal channels are formed on an outer periphery of the projection. At least one of the plurality of channels serves as an ink channel and at least one of the other channels serves as an air intake path.

A writing instrument includes: a writing instrument body and an ink cartridge. The ink cartridge includes a bottomed cylindrical container with an opened front end and a plug fitted into an inner circumferential surface of an opening of the container. The writing instrument body includes a projection that opens the ink cartridge when inserted into the opening to press the plug rearward and an air tight connecting portion, formed separately from the projection, that surrounds the projection. The opening is divided into a plurality of openings by air tight fitting the opening in the air tight connecting portion. A plurality of longitudinal channels are formed on an outer periphery of the projection. At least one of the plurality of channels serves as an ink channel and at least one of the other channels serves as an air intake path.

An ink and method of conducting an examination suitable for reducing the likelihood that the students' answers on paper-based examinations may be changed at a later time prior to being graded. The ink includes a solution of marking particles, a suspension material, and a preserving material. A mark made with the ink is initially erasable for a predetermined period of time after the mark is formed and after the expiration of the predetermined period of time the mark is not erasable. The method of conducting an examination includes providing an ink to an individual, and then providing questions to an individual wherein the individual indicates answers to the questions by producing marks with the ink.

A liquid applying tool which can create pressurizing action with a simple structure and without any labor at the time of using the liquid applying tool, and allows liquid to be smoothly fed to a tip end of a liquid applicator member with the assistance of the pressurizing action.

A liquid applying tool which can create pressurizing action with a simple structure and without any labor at the time of using the liquid applying tool, and allows liquid to be smoothly fed to a tip end of a liquid applicator member with the assistance of the pressurizing action.

A waterproof paint formula and a pen device for using the same. 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. 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 plurality of inlets are defined in a circulation path between an ink reservoir and an ink absorbing member by an inlet forming part formed in the circulation path.

A plurality of inlets are defined in a circulation path between an ink reservoir and an ink absorbing member by an inlet forming part formed in the circulation path.

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.