[57] A cartridge for a pen, the cartridge including: a cartridge body; a marking device operative to mark a visible path onto a surface, the marking device being electronically controllable to change the value of at least one attribute of the path; a non marking stylus nib moveable relative the cartridge body, and an on/off switch and wherein the on/off switch is turned to an "on" state upon sensing of more than a predetermined amount of movement of the stylus nib relative to the cartridge body or application of more than a predetermined compressive force to the stylus nib; wherein the stylus nib is movable relative to the cartridge body along a first axis, the stylus nib including a slot or groove extending at other than 0˚ or 90˚ to the first axis and wherein the marking device includes: a printhead; and wherein the capping device is mounted in front of the printhead and rotatable about a second axis parallel to the first axis between the open and closed positions, the capping device including an arm engaging the slot or groove, whereby movement of the stylus nib relative to the cartridge body along the first axis moves the capping device between the open and closed positions.
