Provided is an aqueous ink composition for a writing instrument which is excellent in a drying property of drawn lines and a low temperature stability of the ink while inhibiting the pen tip from drying and which prevents the drawn lines from causing feathering and strike-through. The aqueous ink composition for a writing instrument described above contains at least a colorant, trimethylglycine, pentaerythritol, 10% by mass or less of a water-soluble organic solvent and water.

Provided is an aqueous ink composition for a writing instrument which is excellent in a drying property of drawn lines and a low temperature stability of the ink while inhibiting the pen tip from drying and which prevents the drawn lines from causing feathering and strike-through. The aqueous ink composition for a writing instrument described above contains at least a colorant, trimethylglycine, pentaerythritol, 10% by mass or less of a water-soluble organic solvent and water.

A thermochromic writing instrument including a writing body, storing a thermochromic ink therein, stored in a barrel; an operation body provided in the barrel to be operated to longitudinally move the writing body; a nib of the writing body configured to be capable of appearing from a front end of the writing instrument, wherein the writing instrument 1 further includes a friction unit, for rubbing handwriting in the thermochromic ink and capable of thermally changing the color of the handwriting by frictional heat generated at that time, and at least one clip body as the operation body, the friction unit 10 is provided at a rear end of the barrel, and the clip body is provided in an area other than the rear end of the barrel.

A barrel assembly according to an embodiment includes one barrel having an annular engaging projection; and another barrel having an engaging projection that protrudes toward the annular engaging projection of the one barrel, wherein the engaging projection of the other barrel has an engaging edge that protrudes in a direction of engagement, the engaging edge further has a protruding molded part that further protrudes from the engaging edge in the direction of engagement, and the protruding molded part of the engaging edge of the other barrel engages with the annular engaging projection of the one barrel.

Provided is a writing tool comprising a clip composed of a wire rod, wherein the writing tool is capable of allowing a user to raise the clip without manipulation with both hands. The writing tool 1 comprises a tool body 7 extending in a longitudinal direction, and a clip member 8 composed of a wire rod and held by a lateral portion of the tool body 7, wherein a longitudinal intermediate portion 8B of the clip member 8 is held by the lateral portion of the tool body 7, and the clip member 8 is biased toward the tool body 7 so as to cause a longitudinal fore-end portion 8A of the clip member 8 to come into contact with the tool body 7, and wherein the writing tool is configured such that, when a back-end portion 8C of the clip member 8 is pushed toward the tool body 7, the fore-end portion 8A of the clip member 8 is swung to be spaced apart from the tool body 7.

A multi-purpose combination writing instrument is provided. The instrument can comprise a writing instrument holder, with 2 casing members connected together by a retractable unwinding tool. The retractable unwinding tool can be automatically retractable. One or more removable individual writing instruments can be reversibly attached to the writing instrument holder. An individual writing instrument is provided that comprises a male connector adapted to be mated to a corresponding female connector or that comprises an external screw thread. A casing member of a writing instrument holder is provided, comprising an automatic retracting mechanism stored in the casing member and adapted to be attached to a retractable unwinding tool and adapted to allow the retractable unwinding tool to automatically retract. Another multi-purpose combination writing instrument is provided, comprising a writing instrument holder that is fan-shaped (like a hand-held fan). Yet another multi-purpose combination writing instrument is provided, comprising a writing instrument holder comprising zero, one, or two casing members comprising a hinge assembly, which comprises a hinge.

A writing instrument having a writing part, having a writing tip, and having a protective cap which protects, the writing tip and is releasably connectable to the writing part. For the releasable connection between the cap and writing part, the writing part has several connecting structures, each with a connecting region which is curved in an ellipsoidal, ball-shaped manner, such as balls or semi-spheres, and the cap has an internal thread on the inside. The internal thread of the cap and the connecting structure of the writing part are positioned and aligned with each other in such a manner that, in each case with the cap in a state fastened on the writing part, the connecting region of the respective connecting structure engages completely or in part in a or the thread of the internal thread.

A mess-free coloring system comprising a coloring medium and optionally one or more coloring utensils is disclosed. The coloring medium can include a substrate with or without decorative effects and one or more coating layers on a surface of the substrate. In various examples, the one or more coating layers include a color-triggering developer, e.g., in the form of a substantially clear resin, and an opaque pigment. Decorative effects integrated with or disposed on the substrate, while initially obscured by the one or more coating layers, can be revealed when the coating layers are mixed with at least one color precursor stored and dispensed from a coloring utensil. The opaque pigment is selected and configured such that, upon receipt of at least one color precursor by the one or more coating layers, a change in the pigment's reflective index occurs as the pigment dissolves into the clear resin developer.

A mess-free coloring system comprising a coloring medium and optionally one or more coloring utensils is disclosed. The coloring medium can include a substrate with or without decorative effects and one or more coating layers on a surface of the substrate. In various examples, the one or more coating layers include a color-triggering developer, e.g., in the form of a substantially clear resin, and an opaque pigment. Decorative effects integrated with or disposed on the substrate, while initially obscured by the one or more coating layers, can be revealed when the coating layers are mixed with at least one color precursor stored and dispensed from a coloring utensil. The opaque pigment is selected and configured such that, upon receipt of at least one color precursor by the one or more coating layers, a change in the pigment's reflective index occurs as the pigment dissolves into the clear resin developer.

A writing instrument comprises an elongated barrel having a first end, a second end and a plurality of sides including at least three sides, each side having data printed along its length at uniform spacing increments from the first end, the data on any two sides that share the same distance from the first end are computationally related to the data on another side that shares the same distance from the first end. The data includes at least one of a numerical data or a phonic alphabet. The numerical data on a first side and a third side is linked to a sign that associated with an arrow respectively to indicate the direction to which the writing instrument should be rotated to signify the computation relation. Thus, the elongated barrel defines a triangular shaped writing instrument that allows a user to learn the computation relation between the data.