An ink reservoir element for use in a marking instrument is disclosed, which combines good ink holding capacity and good ink release properties with a wide variety of inks. The ink reservoir element is formed from a coherent sheet of flexible thermoplastic fibrous material, such as a spunbonded polyester fabric or a foam-attenuated extruded polyester fabric, which has been uniformly embossed with a series of parallel grooves. The embossed sheet is compacted and bonded into a dimensionally stable rod-shaped body whose longitudinal axis extends parallel to the embossed grooves. A method and apparatus is disclosed for continuous production of the ink reservoir elements from a continuous web of the fibrous sheet material.