US Patent 7232271 Writing implement

A writing implement 1 includes a sensor 11 and control circuitry 13 so that when the writing implement is brought into close proximity with an input screen, the writing tip 3 of the writing implement 1 is prevented from delivering ink to the input screen. This may be achieved in one embodiment by retracting the writing tip within the body of the writing implement, or by extending a stylus tip 20 beyond the writing tip 3. In other embodiments, ink can be prevented from delivered to the input screen by a mechanism which disengages an ink reservoir 5 from the writing tip 3 of the writing implement 1 and/or, in the case of a ball-point pen type writing tip 3, electromagnets 26 can be arranged to prevent rotation of an ink delivery ball 22.