A mechanical pencil unit is provided which includes: a holding tube; a holder which is inserted into a front side opening portion of the holding tube and which protrudes forward from a front end of the holding tube, and moreover which is supported so as to be back and forth movable relative to the holding tube; a pencil lead delivering mechanism which delivers forward a pencil lead x inserted into the holder; and a movement direction conversion mechanism which causes the holder to go forward relative to the holding tube and the pencil lead x by using a force applied in a radial direction from the pencil lead x to the holder, wherein the pencil lead delivering mechanism is provided at a position further toward a rearward side than the holder and the movement direction conversion mechanism.

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 loosely fitted onto an inner periphery of the opening of the shaft cylinder to be movable in an axial direction of the shaft cylinder with respect to the shaft cylinder, and an elastic member capable of connecting the tip holder and the annular member such that the tip holder and the annular member are movable relatively to each other. A contact surface tapered toward the front end is formed on at least a part of an outer periphery of the annular member. A cutout is formed at a part of the annular member such that an inner diameter of the annular member is reduced when a load is received by the contact surface. A guide surface tapered toward the front end is formed on the part of the inside surface of the shaft cylinder. The contact surface is configured to receive the load from the guide surface in conjunction with the movement of the tip holder toward the front end side.

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 loosely fitted onto an inner periphery of the opening of the shaft cylinder to be movable in an axial direction of the shaft cylinder with respect to the shaft cylinder, and an elastic member capable of connecting the tip holder and the annular member such that the tip holder and the annular member are movable relatively to each other. A contact surface tapered toward the front end is formed on at least a part of an outer periphery of the annular member. A cutout is formed at a part of the annular member such that an inner diameter of the annular member is reduced when a load is received by the contact surface. A guide surface tapered toward the front end is formed on the part of the inside surface of the shaft cylinder. The contact surface is configured to receive the load from the guide surface in conjunction with the movement of the tip holder toward the front end side.

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.

Disclosed is a knock-type pen, which includes: a housing having a -shaped guide groove formed at a top end thereof; a pen seam accommodated in the housing; a pressing member having a moving protrusion provided at a lower end thereof and movably inserted into the guide groove; a rotating member rotatably coupled to an outer circumference of the top end of the housing and having a l-shaped slide groove into which an end of the moving protrusion inserted into the guide groove is movably inserted; and a knock unit disposed between the pressing member and the pen seam and configured to allow an end of the pen seam to move in and out at a lower end of the housing when the pressing member is pressed.

Disclosed is a knock-type pen, which includes: a housing having a -shaped guide groove formed at a top end thereof; a pen seam accommodated in the housing; a pressing member having a moving protrusion provided at a lower end thereof and movably inserted into the guide groove; a rotating member rotatably coupled to an outer circumference of the top end of the housing and having a l-shaped slide groove into which an end of the moving protrusion inserted into the guide groove is movably inserted; and a knock unit disposed between the pressing member and the pen seam and configured to allow an end of the pen seam to move in and out at a lower end of the housing when the pressing member is pressed.

A press structure for a press type stationery, having mounting board (1), a button (400) and a resilient piece. The mounting board has a recess (11). A position limiting block (12) is provided at the front surface of the mounting board in this recess. A closed loop sliding track is formed between outer walls of the position limiting block and inner walls of the recess. The resilient piece has a spring (2) and a resilient rod (3). The position limiting block has a first inclined surface (122) and a second inclined surface (123). End portions of the first and second inclined surfaces are at one side of the resilient rod; upper ends of the first and second inclined surfaces are at another opposite side of the resilient rod. A contact part (4) positioned within the sliding track is provided at an upper end portion of the resilient rod.

A ballpoint pen. In the ballpoint pen, an oil-based ballpoint pen ink composition has an ink viscosity with a range of 500 mPa.Math.s to 15000 mPa.Math.s inclusive at 20? C. and a shear rate of 500 sec.sup.?1. A ball has a ball diameter of 0.5 mm or less. A tip distal end portion includes a first swaged portion and a second swaged portion. The first swaged portion has an inclination angle with a range of 90 degrees to 100 degrees inclusive. The second swaged portion is provided closer to a distal end side of a ballpoint pen tip than the first swaged portion and has an inclination angle with a range of 110 degrees to 130 degrees inclusive. An angle of a bottom wall of a ball holding chamber is the same as the inclination angle of the second swaged portion.

A ballpoint pen. In the ballpoint pen, an oil-based ballpoint pen ink composition has an ink viscosity with a range of 500 mPa.Math.s to 15000 mPa.Math.s inclusive at 20? C. and a shear rate of 500 sec.sup.?1. A ball has a ball diameter of 0.5 mm or less. A tip distal end portion includes a first swaged portion and a second swaged portion. The first swaged portion has an inclination angle with a range of 90 degrees to 100 degrees inclusive. The second swaged portion is provided closer to a distal end side of a ballpoint pen tip than the first swaged portion and has an inclination angle with a range of 110 degrees to 130 degrees inclusive. An angle of a bottom wall of a ball holding chamber is the same as the inclination angle of the second swaged portion.