The nib comprises a base portion 21, having comb-tooth pieces 22, and a sleeve 3 which forces the comb-tooth pieces together so that the front ends 24 form a hemi-spherical writing tip 26 with ink passages 23 between the adjoining comb-tooth pieces. When the writing tip is pressed against paper with the pen axis inclined, the portions 24 of the tip shift relative to one another and elastically deform to expand the outer diameter of the tip. The base portion and comb-tooth pieces are formed by injection moulding.
