A writing instrument excellent in handwriting density and temporal stability. The writing instrument includes a ball-point pen tip attached to the front end portion of the ink storage cylinder; and a ball-point pen refill having an ink composition for a writing instrument loaded therein. The ink composition for the writing instrument is a thermochromic ink containing at least a thermochromic microcapsule pigment. The writing instrument includes a pressurization mechanism for applying a pressure to the back end of the ink composition for the writing instrument.

A writing instrument excellent in handwriting density and temporal stability. The writing instrument includes a ball-point pen tip attached to the front end portion of the ink storage cylinder; and a ball-point pen refill having an ink composition for a writing instrument loaded therein. The ink composition for the writing instrument is a thermochromic ink containing at least a thermochromic microcapsule pigment. The writing instrument includes a pressurization mechanism for applying a pressure to the back end of the ink composition for the writing instrument.

A retractable writing instrument includes a push member including a clip and a protruding and retracting mechanism that causes a pen point to protrude from and retract into a front end of the barrel at a frontward press on the push member, without the push member rotating with respect to the instrument. The protruding and retracting mechanism includes cam teeth and cam grooves formed in an inner face of the barrel, a rotary member including protuberances engageable alternately with the cam teeth or the cam grooves, a cam member connected to the push member and includes cam projections rotating the rotary member, and engagement projections engaged with the cam grooves in the inner face of the barrel so as to be movable in the longitudinal direction; and a resilient element that biases the writing element rearward. The push member and the cam member are in detent engagement with each other.

A retractable writing instrument includes a push member including a clip and a protruding and retracting mechanism that causes a pen point to protrude from and retract into a front end of the barrel at a frontward press on the push member, without the push member rotating with respect to the instrument. The protruding and retracting mechanism includes cam teeth and cam grooves formed in an inner face of the barrel, a rotary member including protuberances engageable alternately with the cam teeth or the cam grooves, a cam member connected to the push member and includes cam projections rotating the rotary member, and engagement projections engaged with the cam grooves in the inner face of the barrel so as to be movable in the longitudinal direction; and a resilient element that biases the writing element rearward. The push member and the cam member are in detent engagement with each other.

A writing implement includes a housing for receiving a refill, an operating side and a writing side. An adjustment mechanism in the housing has a guide bushing and a cam pin concentrically arranged therein and spring-loaded along the longitudinal axis on the refill, which cam pin engages an end of the refill. The cam pin has at least two locking positions, which are offset along the longitudinal axis. The writing implement includes a control arrangement having a resetting device, a freewheel couplable with an operating unit arranged at the operating side and a cam bushing couplable with the freewheel. The resetting device exerts a resetting force onto the operating unit. The freewheel is a rotatably supported body having a circumferential recess and forms an operative connection in a region with a second body that is rotatably supported and concentrically thereto. One of the first and second rotatably supported bodies is freely rotatable around its longitudinal axis in an angle range and transfers a rotation from the operating unit to the cam bushing outside of this range.

A writing implement includes a housing for receiving a refill, an operating side and a writing side. An adjustment mechanism in the housing has a guide bushing and a cam pin concentrically arranged therein and spring-loaded along the longitudinal axis on the refill, which cam pin engages an end of the refill. The cam pin has at least two locking positions, which are offset along the longitudinal axis. The writing implement includes a control arrangement having a resetting device, a freewheel couplable with an operating unit arranged at the operating side and a cam bushing couplable with the freewheel. The resetting device exerts a resetting force onto the operating unit. The freewheel is a rotatably supported body having a circumferential recess and forms an operative connection in a region with a second body that is rotatably supported and concentrically thereto. One of the first and second rotatably supported bodies is freely rotatable around its longitudinal axis in an angle range and transfers a rotation from the operating unit to the cam bushing outside of this range.

A writing instrument assembly has a writing instrument with a body and a working tip extended or extendable from the body. A holder has a landing spot for the writing instrument. The writing instrument is magnetically and detachably retained at the landing spot when attached to the holder. The working tip is sheathed or covered automatically when the writing instrument is attached to the holder and is unsheathed or uncovered when detached from the holder.

A writing instrument assembly has a writing instrument with a body and a working tip extended or extendable from the body. A holder has a landing spot for the writing instrument. The writing instrument is magnetically and detachably retained at the landing spot when attached to the holder. The working tip is sheathed or covered automatically when the writing instrument is attached to the holder and is unsheathed or uncovered when detached from the holder.

A knock type pen includes a body in which a lead and a spring which provides an elastic force to the lead are received, and a knock section which is coupled to a rear end of the body and includes a knock body and a rotary cam to push the lead out of a tip of the body or receive the lead inside, wherein the knock type pen includes a cutout groove which extends in one direction along an axial direction of the body, a slit hole which extends along a downward direction from an upper end of the cutout groove, an insert hole which is formed in a direction perpendicular to the slit hole from the upper end of the cutout groove, and a locking section which moves up and down along the slit hole.

A knock type pen includes a body in which a lead and a spring which provides an elastic force to the lead are received, and a knock section which is coupled to a rear end of the body and includes a knock body and a rotary cam to push the lead out of a tip of the body or receive the lead inside, wherein the knock type pen includes a cutout groove which extends in one direction along an axial direction of the body, a slit hole which extends along a downward direction from an upper end of the cutout groove, an insert hole which is formed in a direction perpendicular to the slit hole from the upper end of the cutout groove, and a locking section which moves up and down along the slit hole.