A writing instrument includes: a replacement ink cartridge including a bottomed cylindrical container that has an opened front end and a closed rear end and a plug fitted into an inner circumferential surface of an opening of the container; and a projection inserted into the opening of the container to press the plug rearward, thereby opening the plug of the ink cartridge, wherein the projection and the plug are fitted when the plug is press opened, and when the cartridge is replaced, the fitting between the projection and the plug is released and the plug is locked again in the opening of the container.

A writing instrument includes: a replacement ink cartridge including a bottomed cylindrical container that has an opened front end and a closed rear end and a plug fitted into an inner circumferential surface of an opening of the container; and a projection inserted into the opening of the container to press the plug rearward, thereby opening the plug of the ink cartridge, wherein the projection and the plug are fitted when the plug is press opened, and when the cartridge is replaced, the fitting between the projection and the plug is released and the plug is locked again in the opening of the container.

An apparatus includes a pen. The pen includes a reservoir configured to store a fluid. The pen also includes a tip configured to transfer the fluid from the reservoir onto a surface of an object during writing. The pen further includes a regulator configured to control a flow of the fluid from the reservoir to the tip. The apparatus also includes the fluid stored within the reservoir. The fluid includes a carrier fluid and particles of an X-Ray opaque material.

An apparatus includes a pen. The pen includes a reservoir configured to store a fluid. The pen also includes a tip configured to transfer the fluid from the reservoir onto a surface of an object during writing. The pen further includes a regulator configured to control a flow of the fluid from the reservoir to the tip. The apparatus also includes the fluid stored within the reservoir. The fluid includes a carrier fluid and particles of an X-Ray opaque material.

A pressure fluctuation buffering mechanism includes a buffer space connected to a brush via a paint flow space (a paint tank and a paint feeder) through which paint flows. The pressure fluctuation buffering mechanism buffers pressure fluctuations in the paint tank by the flow of paint and air between the paint flow space and the buffer space. The pressure fluctuation buffering mechanism includes a first buffer space forming member for forming a first buffer space in the buffer space, and a second buffer space forming member for forming a second buffer space in the buffer space. The paint between the first buffer space and the paint flow space flows more easily than the paint between the second buffer space and the paint flow space.

A pressure fluctuation buffering mechanism includes a buffer space connected to a brush via a paint flow space (a paint tank and a paint feeder) through which paint flows. The pressure fluctuation buffering mechanism buffers pressure fluctuations in the paint tank by the flow of paint and air between the paint flow space and the buffer space. The pressure fluctuation buffering mechanism includes a first buffer space forming member for forming a first buffer space in the buffer space, and a second buffer space forming member for forming a second buffer space in the buffer space. The paint between the first buffer space and the paint flow space flows more easily than the paint between the second buffer space and the paint flow space.

Provided is a valve type writing instrument, eliminating the need for frequently making a core pushing-in operation, thus being long-lasting, and causing no blurring of a written character. The valve type writing instrument includes an ink tank barrel; a valve housing cylinder, fitted into the ink tank barrel; and a core, slidably held in the valve housing cylinder, in which an ink reservoir member, reservoiring ink, and a valve unit case, incorporating a valve mechanism are loaded. The ink reservoir member has a truncated cone shape, a core insertion hole being formed so as to be penetrated through the central portion thereof, one half part of core being slidably housed therein, a number of slits for reservoiring ink being radially formed from the core insertion hole, and ink reservoired in the slits being capable of permeating into the housed portion of core in the core insertion hole as needed.

Provided is a valve type writing instrument, eliminating the need for frequently making a core pushing-in operation, thus being long-lasting, and causing no blurring of a written character. The valve type writing instrument includes an ink tank barrel; a valve housing cylinder, fitted into the ink tank barrel; and a core, slidably held in the valve housing cylinder, in which an ink reservoir member, reservoiring ink, and a valve unit case, incorporating a valve mechanism are loaded. The ink reservoir member has a truncated cone shape, a core insertion hole being formed so as to be penetrated through the central portion thereof, one half part of core being slidably housed therein, a number of slits for reservoiring ink being radially formed from the core insertion hole, and ink reservoired in the slits being capable of permeating into the housed portion of core in the core insertion hole as needed.

An improved retractable liquid dispenser device comprises an outer body having an internal channel communicating with an open first end. A liquid dispenser includes a supply reservoir and a discharge reservoir with a valve disposed therebetween. A retractable mechanism slidably supports the liquid dispenser within the outer body. A retractable valve is located in proximity to the open first end of the outer body. A first depression of the retractable actuator opens the retractable valve and moves the liquid dispenser into the extended position for enabling a depression of the distal end of the liquid applicator to open the dispensing valve to permit liquid to flow from the supply reservoir into the dispensing reservoir to dispense the applicator liquid from the distal end of the liquid applicator. A second depression of the retractable actuator moves the liquid dispenser into the retracted position and closes the retractable valve to enclose the distal end of the liquid applicator within the outer body.

An improved retractable liquid dispenser device comprises an outer body having an internal channel communicating with an open first end. A liquid dispenser includes a supply reservoir and a discharge reservoir with a valve disposed therebetween. A retractable mechanism slidably supports the liquid dispenser within the outer body. A retractable valve is located in proximity to the open first end of the outer body. A first depression of the retractable actuator opens the retractable valve and moves the liquid dispenser into the extended position for enabling a depression of the distal end of the liquid applicator to open the dispensing valve to permit liquid to flow from the supply reservoir into the dispensing reservoir to dispense the applicator liquid from the distal end of the liquid applicator. A second depression of the retractable actuator moves the liquid dispenser into the retracted position and closes the retractable valve to enclose the distal end of the liquid applicator within the outer body.