A knock type writing tool is provided, in which an appropriate amount of air can be taken in depending on an amount of a thermochromic ink discharged from a pen tip, so that the thermochromic ink can be smoothly discharged from the pen tip, and in which a writing body can rotate surely in conjunction with a rotation of a rotating member. An air hole 63a and a plurality of projection pieces 63b are provided at a rear end portion of a writing body 6. A front surface of a projection and retraction rotating member 7 is provided with a plurality of abutment parts 73, on which respective rear ends of the plurality of projection pieces 63b are to abut, and with a plurality of protrusion parts 72, each of which is formed between the plurality of abutment parts 73 and protruded more forward than the plurality of abutment parts 73. The protrusion parts 72 are respectively inserted in gaps 63c between the projection pieces 63b. An axial length of each projection piece 63b is longer than an axial length of each protrusion part 72, so that a portion of the gap 63c is left more forward than a front end of each protrusion part 72.

There is a compound represented by the following formula (I): ##STR00001##
in which R1 and R2, identical or different, represent a C.sub.2-C.sub.30 alkyl group, a C.sub.2-C.sub.30 alkenyl group, a C.sub.2-C.sub.30 alkynyl group, or a C.sub.2-C.sub.30 alkoxy group, the alkyl, alkenyl, alkynyl, or alkoxy groups being optionally substituted with at least one hydroxy, halogen, amino, C.sub.1-C.sub.8 alkyl, or C.sub.1-C.sub.8 alkoxy group, as a temperature change regulating agent in a thermochromic ink composition. There also are thermochromic pigment microcapsules having a compound of formula (I) according to the disclosure, to ink compositions having such thermochromic pigment microcapsules, and to writing instruments comprising such ink compositions.

There is a compound represented by the following formula (I): ##STR00001##
in which R1 and R2, identical or different, represent a C.sub.2-C.sub.30 alkyl group, a C.sub.2-C.sub.30 alkenyl group, a C.sub.2-C.sub.30 alkynyl group, or a C.sub.2-C.sub.30 alkoxy group, the alkyl, alkenyl, alkynyl, or alkoxy groups being optionally substituted with at least one hydroxy, halogen, amino, C.sub.1-C.sub.8 alkyl, or C.sub.1-C.sub.8 alkoxy group, as a temperature change regulating agent in a thermochromic ink composition. There also are thermochromic pigment microcapsules having a compound of formula (I) according to the disclosure, to ink compositions having such thermochromic pigment microcapsules, and to writing instruments comprising such ink compositions.

A writing instrument, in particular a pen, comprises a housing comprising a front barrel and a rear barrel, the front barrel having a front opening, two or more cartridges for storing colorants or inks, each cartridge having a writing tip, at least one actuator for selectively moving one of the cartridges within the housing so that the writing tip of a selected cartridge extends through the front opening of the front barrel, and a cartridge guide member which is designed to guide the movement of the cartridges within the housing. The front barrel and the cartridge guide member are designed to be removed from the rear barrel for replacing one or more of the cartridges. In particular, the front barrel and the cartridge guide member may be removed from the rear barrel while the cartridge guide member may remain mounted to the front member at the same time.

The adaptation of a pocket-size pen for use by a person is provided. The pen includes a cap with internally configured male threads, and a body. The body includes a barrel with externally configured and spaced apart first set of female threads, and second set of female threads. The barrel is hollow inside with a top opening for receiving a full-sized standard ink source. The male threads of the cap engage the second set of female threads of the pen body for closing a writing tip and reducing the length of the pen for storage in the pocket of a user. The male threads of the cap engage the first set of female threads of the body for transforming the pen into an extended-length pen similar in length to a conventional pen and revealing the writing tip for comfortable writing using the pen.

A retractive writing utensil includes a shaft tube, a core stored in the shaft tube in such a manner as to protrude from a front end of the shaft tube when moved forward, and an urging member that is stretched and contracted in the shaft tube in a front-rear direction, wherein the urging member is located adjacent to the core radially outward in such a manner that the center of the urging member is positioned radially outside the core, and urges the core rearward.

There is a non-thermochromic irreversible color changing aqueous writing ink including core-shell dye microparticles and a coloring agent, in which the core of the core-shell dye microparticles includes an organic solvent immiscible with water and at least one dye soluble in the organic solvent and the shell includes a resin component. There also is a writing instrument containing it and the process of preparation of this ink.

A pen comprising a shaft, a gripping zone, and a measuring device having a sensor configured to measure a force acting on the gripping zone. The pen further comprises a cover in the area of the gripping zone, the cover configured to cover the measuring device.

The present invention provides a thermochromic color-memory composition including (a) an electron-donating color-developing organic compound, (b) an electron-accepting compound, and (c) an ester compound represented by the following formula (1) or (2), as a reaction medium which controls color reaction of the component (a) and the component (b); and a thermochromic color-memory microcapsule pigment encapsulating the thermochromic color-memory composition. ##STR00001##

A writing instrument includes a body, a nosecone, and an adaptor each being of generally hollow tubular shape. The body, the nosecone, and the adaptor each have a first end and a second end. The first end of the adaptor is configured to slidably couple to the nosecone second end. The second end of the adaptor is coupled to the first end of the body. The writing instrument includes a writing element with a mounting end and a writing end where the mounting end is removably coupled to the second end of the body. The writing instrument includes a locking mechanism configured to selectively lock the nosecone in a storage position or a writing position. In the storage position, the nosecone extends and covers the writing end. In the writing position, the nosecone retracts and the writing end of the writing element extends beyond the nosecone.