Ink follower piston for a ball-point pen, and a method of manufacturing the same

A method of making a follower piston having an element in the form of a stable gel of hardness measured by cone penetration lying in the range 100×10−1 mm to 400×10−1 mm, for use in a pen of the type having an ink-reservoir forming tube fitted at one end with a ball-point carrier and a ball point, the method being characterized in that:

• a liquid reaction medium is introduced into the tube via its open end remote from the point and above the ink;
• and
• the gel element is produced by the liquid medium reacting chemically in situ.

A follower piston for a ball-point pen, characterized in that the follower piston comprises a liquid or gel element in which a solid element having an array of open pores is introduced at least in part.

A follower piston for a ball-point pen, the piston comprising an element in the form of a liquid element and an at least partly immersed porous solid element, the solid element being formed by a bar of extruded plastics material obtained from a mixture of an expansion agent and at least one component selected from polyolefins, polystyrene, and ABS, the solid element having a hardness measured by cone penetration lying in the range 100×10−1 mm to 400×10−1 mm.

A follower piston for a ball-point pen, the piston comprising an element in the form of a liquid element and an at least partly immersed porous solid element, the solid element being formed by thermoadhered high molecular weight polyethylene powder the solid element having a hardness measured by cone penetration lying in the range 100×10−1 mm to 400×10−1mm.