Imaging apparatus including a photoreceptor, a charging station operative to charge the photoreceptor including an active length of corona wire operatively juxtaposed with the photoreceptor and a corona wire dispenser containing an undispensed length of corona wire contiguous with the active length and at least as long as the active length. The apparatus also includes an exposure station operative to selectively discharge portions of the photoreceptor to form a latent image thereon and a developer operative to develop the latent image. The corona wire dispenser is operative to dispense an appropriate length of the undispensed corona wire to replace the active length of corona wire. The corona wire dispenser preferably includes a dispensing bobbin around which the undispensed corona wire is wound, a lever-plate on which the dispensing bobbin is rotatably mounted, a friction pin and apparatus operating on the lever-plate for forcing an edge of the dispensing bobbin into contact with the friction pin with a given force whereby the undispensed corona wire is dispensed from the dispensing bobbin when tension in the corona wire is greater than a first threshold tension which is directly proportional to the given force and wherein wire continues to be drawn so long as the tension in the corona wire is greater than a second threshold tension.