Ball point pen

Claim 1

A ball point pen comprising an elongated ink reservoir terminating at one end in writing means and at an opposite end in an opening, a supply of ink within said reservoir to a level below its open end, and an end closure of heat fusible material for said open end and serving to limit one end of a solely fluid filled, fluid pressurized, chamber delimited at its opposite end by said ink level, said end closure comprising an enlarged head portion having an outer end face and an axially extending stem portion projecting from an inner face of said enlarged head portion opposite said outer face into said reservoir, said stem portion being formed throughout its length with at least one longitudinally extending groove terminating inwardly of said outer face of the head portion, said end closure having first and second positions in relation to said reservoir, said inner face of the enlarged head portion in said first position of said closure being spaced from the open end of said reservoir with its stem portion and groove therein at least partially introduced within said reservoir and being in sealing engagement with the reservoir open end in said second position of the closure, and an external source supplied fluid in said reservoir supplied therein via said longitudinally extending groove in said first position of said end closure and during positioning thereof to said second position in which said groove is wholly within said reservoir and sealed against communication with the atmosphere.