The present invention includes a shaft cylinder having an opening at a front end thereof, a tip holder movable in an axial direction of the shaft cylinder, a tip projectable and retractable in conjunction with a movement of the tip holder, an annular member fitted on the tip holder and axially movable, and an elastic member connecting the tip holder and the annular member so that they are movable relatively to each other. A contact surface tapered toward the front end is formed on an outer periphery of the annular member. A cutout reduces an inner diameter of the annular when a load is received by the contact surface. A guide surface is formed on the part of the inside surface of the shaft cylinder. The contact surface receives the load from the guide surface in conjunction with the movement of the tip holder toward the front end side.

In a writing utensil with a pressurizing mechanism, a cylinder is provided such that it comes into sliding contact with an outer peripheral part of a valve element and moves back and forth. An inner wall face of the cylinder is provided with a ventilating recess communicating with outside air, and an annular non-pressure contact face is positioned on the rear side of the ventilating recess. When the cylinder moves forwardly, the valve element is brought into pressure contact with the non-pressure contact face to seal the pressurizing chamber and when the cylinder moves backwardly, the valve element is moved forward and is separated from the non-pressure contact face, such that the ventilating recess communicates with the pressurized chamber.

In a writing utensil with a pressurizing mechanism, a cylinder is provided such that it comes into sliding contact with an outer peripheral part of a valve element and moves back and forth. An inner wall face of the cylinder is provided with a ventilating recess communicating with outside air, and an annular non-pressure contact face is positioned on the rear side of the ventilating recess. When the cylinder moves forwardly, the valve element is brought into pressure contact with the non-pressure contact face to seal the pressurizing chamber and when the cylinder moves backwardly, the valve element is moved forward and is separated from the non-pressure contact face, such that the ventilating recess communicates with the pressurized chamber.

A thermochromic writing tool which includes a writing element including a reservoir in which thermochromic ink is retained, and a writing point portion which is disposed on a front end portion of the reservoir and from which the thermochromic ink is dischargeable; a barrel which is made of a resin and in which the writing element is accommodated so as to be movable in a longitudinal direction; a protruding and retracting mechanism including a push element made of a resin and disposed on a rear end portion of the barrel so as to be tiltable in a radial direction relative to an axis of the barrel; and a rub portion disposed on a rear end portion of the push element 5.

A thermochromic writing tool which includes a writing element including a reservoir in which thermochromic ink is retained, and a writing point portion which is disposed on a front end portion of the reservoir and from which the thermochromic ink is dischargeable; a barrel which is made of a resin and in which the writing element is accommodated so as to be movable in a longitudinal direction; a protruding and retracting mechanism including a push element made of a resin and disposed on a rear end portion of the barrel so as to be tiltable in a radial direction relative to an axis of the barrel; and a rub portion disposed on a rear end portion of the push element 5.

A thermochromic writing instrument capable of causing curiosity and interest of a user by configuring an eraser to be easily separated from the main body of the thermochromic writing instrument and to be shaped into various character dolls. A rotation member is inserted into a pen body and a hollow upper cover is detachably coupled to an outside of the upper portion of the pen body, a first eraser is connected to the rotation member by a connection member, a connection portion of an operation member is disposed in a groove formed at one side of the side wall of the pen body, the first body portion of the operation member is inserted into the pen body and a clip portion of the operation member is exposed to the outside of the pen body.

A thermochromic writing instrument capable of causing curiosity and interest of a user by configuring an eraser to be easily separated from the main body of the thermochromic writing instrument and to be shaped into various character dolls. A rotation member is inserted into a pen body and a hollow upper cover is detachably coupled to an outside of the upper portion of the pen body, a first eraser is connected to the rotation member by a connection member, a connection portion of an operation member is disposed in a groove formed at one side of the side wall of the pen body, the first body portion of the operation member is inserted into the pen body and a clip portion of the operation member is exposed to the outside of the pen body.

An electronic pen has increased strength, especially a pen tip portion that is not bent or broken even if the electronic pen is slimmed down. A core unit includes a ferrite core on which a coil is wound and a core rod. The core rod is fixed from a first end of the ferrite core to a second end of the ferrite core at a position including a center axis of the ferrite core and projects at an end thereof from the first end of the ferrite core. The ferrite core includes a first coil non-winding portion on which the coil is not wound provided on the pen tip side of the ferrite core. In operation, the end of the core rod and part of the first coil non-winding portion of the ferrite core project from an opening of a housing of the electronic pen.

An electronic pen has increased strength, especially a pen tip portion that is not bent or broken even if the electronic pen is slimmed down. A core unit includes a ferrite core on which a coil is wound and a core rod. The core rod is fixed from a first end of the ferrite core to a second end of the ferrite core at a position including a center axis of the ferrite core and projects at an end thereof from the first end of the ferrite core. The ferrite core includes a first coil non-winding portion on which the coil is not wound provided on the pen tip side of the ferrite core. In operation, the end of the core rod and part of the first coil non-winding portion of the ferrite core project from an opening of a housing of the electronic pen.

A multifunctional writing instrument comprising a body housing at least two writing elements, each writing element comprising a writing tip, a selection device configured to select one writing element from the at least two writing elements and a retraction device configured to move a selected writing element between a writing position in which the writing tip of the selected writing element protrudes from the body and a retracted position in which the writing tip of the selected writing element is retracted.