Patent ID: 8104983

Claim:
A writing instrument having a longitudinal axis, a proximal end, a distal end, and an outer barrel having an open distal end at said distal end of said writing instrument and a proximal end at said proximal end of said writing instrument, said writing instrument comprising: an inner writing element including a first writing tip adjacent said distal end of said writing instrument and further including a first writing medium reservoir, said first writing medium reservoir having a rear end which is directed towards said proximal end of the outer barrel; an outer writing element which is axially moveable with respect to said outer barrel, said outer writing element including a second writing tip adjacent said distal end of said writing instrument and a second writing medium reservoir joined to said second writing tip, said outer writing element further including an inner axial passage extending through said second writing tip and said second writing medium reservoir, said second writing medium reservoir having a rear end which is directed towards said proximal end of the outer barrel; and a driving mechanism operatively coupled to at least said outer writing element, wherein actuation of said driving mechanism causes axial movement of said outer writing element with respect to said outer barrel, and wherein said first writing medium reservoir is at least partially positioned in said inner axial passage of said outer writing element, said inner and outer writing elements are axially moveable with respect to each other, and said driving mechanism is located at said rear end of said second writing medium reservoir.