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.

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 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 compact writing instrument includes a barrel and a cap. A majority of a length of the barrel and a writing element carried thereby may be received by the cap when the barrel and the cap are placed in a stored position, providing a compact stored arrangement. The cap may be secured to the barrel in a writing arrangement that extends a length of the writing instrument significantly; for example, to a conventional writing instrument length. Engagement features of the cap and barrel may include steep threads that enable the cap to be assembled with and disassembled from the barrel with one rotation (360°) or less. A clip on the cap may include a closed end that defines a receptacle, with the closed end and receptacle extending beyond a corresponding end of the cap. In addition, the closed end and receptacle may extend partially over the corresponding end of the cap.

A compact writing instrument includes a barrel and a cap. A majority of a length of the barrel and a writing element carried thereby may be received by the cap when the barrel and the cap are placed in a stored position, providing a compact stored arrangement. The cap may be secured to the barrel in a writing arrangement that extends a length of the writing instrument significantly; for example, to a conventional writing instrument length. Engagement features of the cap and barrel may include steep threads that enable the cap to be assembled with and disassembled from the barrel with one rotation (360°) or less. A clip on the cap may include a closed end that defines a receptacle, with the closed end and receptacle extending beyond a corresponding end of the cap. In addition, the closed end and receptacle may extend partially over the corresponding end of the cap.

A writing instrument extending between a first end and a second end, the writing instrument including a writing element, a first housing member extending between the first end and the second end and oriented about at least a portion of the writing element, and a second housing member extending between the first end and the second end and oriented about at least a portion of the first housing member, the second housing member being configured to move relative to the first housing member, between a first relative position and a second relative position, and at least a portion of the second housing member being configured to move radially with respect to the first housing member, wherein the relative movement of the second housing member automatically transitions the writing instrument from a writing state toward a non-writing state.

A writing instrument extending between a first end and a second end, the writing instrument including a writing element, a first housing member extending between the first end and the second end and oriented about at least a portion of the writing element, and a second housing member extending between the first end and the second end and oriented about at least a portion of the first housing member, the second housing member being configured to move relative to the first housing member, between a first relative position and a second relative position, and at least a portion of the second housing member being configured to move radially with respect to the first housing member, wherein the relative movement of the second housing member automatically transitions the writing instrument from a writing state toward a non-writing state.

A multi-function writing instrument comprises a body extending in an axial direction and a radial direction, and having at least two writing elements arranged inside the body, each writing element comprising a writing head and a button, at least one button extending in the radial direction through a window and allowing the writing element to be moved between a retracted position in which the writing head is retracted into the body and a writing position in which the writing head projects from the body, and one of the writing elements being a leadholder system comprising a leadholder mechanism and a lead container, the button of the leadholder system comprising a lead-insertion channel extending in the axial direction.

A multi-function writing instrument comprises a body extending in an axial direction and a radial direction, and having at least two writing elements arranged inside the body, each writing element comprising a writing head and a button, at least one button extending in the radial direction through a window and allowing the writing element to be moved between a retracted position in which the writing head is retracted into the body and a writing position in which the writing head projects from the body, and one of the writing elements being a leadholder system comprising a leadholder mechanism and a lead container, the button of the leadholder system comprising a lead-insertion channel extending in the axial direction.

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.