Synthetic resin pen unit

In a pen unit in the form of a bar obtained by fusing a plurality of synthetic resin elements in the axial direction thereof to define a pen unit having a cylindrical outer member of annular cross-section and a plurality of linear members extending inwardly from the inner wall of the cylindrical member;

• the improvement compriisng:
• the unit including at least three bent members and additionally, straight members and protrusions;
• said straight members arranged such that they extend radially inwardly toward said central axis at equal circumferential intervals from the inner wall of said cylindrical member with top portions that terminate short of said central axis;
• said bent members extending inwardly from the inner wall of said cylindrical member such that said bent members are arranged at equal circumferential intervals, each of said bent members having a base portion connected to said cylindrical member and inclined in one direction with respect to an imaginary line connecting the base of said bent member to the central axis of said cylindrical member with each parallel to and adjacent to a straight member and each bent member having an inclined top portion which extends toward the central axis from said base portion in a second direction with respect to said imaginary line, said top portion terminating short of the central axis and short of the top portion of the straight members;
• said small protrusions extending inwardly from the inner wall of said cylindrical member such that said small protrusions are arranged at equal circumferential intervals one between pairs of a parallel straight member and bent member so as to provide in the cavity of said cylindrical member a plurality of voids serving as ink pasages joined to define between said members and protrusions and said cylindrical member throughout the length of said unit essentially equidistant ink passages.