Abstract: In one embodiment, a writing instrument refill includes a first portion having flexibility, and a second portion having a cross-sectional area larger than a cross-sectional area of the first portion, wherein the center of figure of the cross section of the first portion is offset from the center of the figure of the cross section of the second portion, the first portion and the second portion are formed integrally, and a part of the first portion has an outer diameter smaller than an outer diameter of the other part of the first portion.

Abstract: A mechanical pencil includes a writing lead, a chuck that chucks the writing lead and feeds the writing lead forward, and a shaft tube for housing the writing lead and the chuck. When a click operation for feeding the chuck forward is performed, a jet stream flowing forward is generated inside the shaft tube.

Abstract: A mechanical pencil includes a writing lead, a chuck that chucks the writing lead and feeds the writing lead forward, and a shaft tube for housing the writing lead and the chuck. When a click operation for feeding the chuck forward is performed, a jet stream flowing forward is generated inside the shaft tube.

Abstract: A magnetic recording medium has a magnetic layer formed by a thin magnetic metal layer and a carbon protective layer on a non-magnetic substrate; the surface of the carbon protective layer has first protrusions formed by first particles and second protrusions formed by second particles; the carbon protective film has a thickness in the range of 3 nm to 30 nm, while the first protrusions have the heights of 65 nm.+-.15 nm to 95 nm.+-.15 nm and the second protrusions have the heights of 18 nm.+-.5 nm to 28 nm.+-.5 nm; since the surface properties of the carbon protective film are controlled, the electro-magnetic conversion characteristics may be prevented from being lowered due to the spacing losses for improving the running durability of the recording medium.