A writing instrument configured to apply a writing material or liquid to a surface, comprising a socket, and a ball arranged in the socket, characterized by at least one first component which is arranged to come into contact with the ball, wherein the at least one first component comprises a first material having surface properties such that the friction coefficient between the ball and the at least one first component decreases when the force acting from the ball on the at least one first component increases at least within a certain range of forces.

A writing instrument configured to apply a writing material or liquid to a surface, comprising a socket, and a ball arranged in the socket, characterized by at least one first component which is arranged to come into contact with the ball, wherein the at least one first component comprises a first material having surface properties such that the friction coefficient between the ball and the at least one first component decreases when the force acting from the ball on the at least one first component increases at least within a certain range of forces.

The present invention provides a water-based ink composition for a ballpoint pen that is less likely to cause bleeding of a written trace in writing, provides a favorable written trace without causing no blurring or line splitting, and excels in the storage stability of the ink composition; and a water-based ballpoint pen using the ink composition. A water-based ink composition for a ballpoint pen comprising water, a coloring agent, a copolymer having a specific structure; and a water-based ballpoint pen using the ink composition.

Provided is a dispersion liquid of colored resin fine particles for an aqueous ink having excellent stability and a sufficient drawn line intensity; an aqueous ink composition for a writing instrument such as felt-tip pens, marking pens, and ballpoint pens using the dispersion liquid of the colored resin fine particle as a colorant; and a writing instrument loaded with the composition. The dispersion liquid of colored resin fine particles for an aqueous ink includes colored resin fine particles dispersed in water, the colored resin fine particles composed of at least a cyclohexyl (meth)acrylate monomer, and a basic dye or an oil-soluble dye, in which the content of the cyclohexyl (meth)acrylate monomer is 30% by mass or more, and the content of the basic dye or the oil-soluble dye is 15% by mass or more based on the total polymer component constituting the colored resin fine particles.

An ink composition contains a carbon black and/or an organic pigment, water, a polysaccharide, two or more of diols, and particles of an acrylic resin. The two or more of diols include a first diol having from 5 to 7 carbon atoms and a second diol having from 1 to 4 carbon atoms, and a content of the first diol in the ink composition is 0.05 wt % or more.

The invention relates to a pen for cosmetic, writing, drawing, sketching and/or marking purposes, having an inner part and an outer part, wherein the inner part is accommodated in the outer part at least in sections and is fastened therein. According to the invention, it is provided that a fastening device between the inner part and the outer part serves to fasten the inner part to the outer part, which fastening device is elastically deformable and is deformed in the installed state against its elastic restoring force, wherein it is supported on one side on the inner part and on the other side on the outer part by means of the elastic restoring force to fasten the inner part to the outer part.

Convertible writing instrument assemblies are provided, including an outer barrel having a tapered nosecone with an aperture for a writing instrument tip and a grip portion, and an aperture for receiving an eraser or a push button therethrough, wherein the writing instrument assembly provides selective access to a volume defined by the outer barrel, and wherein the outer barrel and the volume are collectively configured to operably and interchangeably receive a mechanical pencil insert having the eraser and a retractable pen insert having the push button. Mechanical pencils and pens utilizing the convertible writing instrument assemblies are also provided, along with kits for providing such mechanical pencils and pens.

A method for manufacturing a ball pen tip, in which a spring for biasing a ball is assembled to the ball pen tip, includes punching the ball pen tip by a punch from a rear end of the ball pen tip along a central axis direction of the ball pen tip to form a plastic flow ridge formed by plastic flow upheaving radially inward from an inner peripheral wall surface of the ball pen tip to assemble the spring to the ball pen tip by the plastic flow ridge.

A method for manufacturing a ball pen tip, in which a spring for biasing a ball is assembled to the ball pen tip, includes punching the ball pen tip by a punch from a rear end of the ball pen tip along a central axis direction of the ball pen tip to form a plastic flow ridge formed by plastic flow upheaving radially inward from an inner peripheral wall surface of the ball pen tip to assemble the spring to the ball pen tip by the plastic flow ridge.

A position indicator that enables a component having a writing function to be easily replaced. The component having the writing function can be inserted/extracted into/from a first housing through a second opening of the first housing. When the second opening of the first housing and a third opening of a second housing are engaged in a state in which the component having the writing function has been inserted into the first housing, a resonant circuit is formed that includes a circuit in which a coil inside the first housing and a writing pressure detector inside the second housing are electrically connected to each other.