Transfer quality enhancement in latent-image electrographic printers - by ionisation of air in space between roller carrying toner particles and counter-electrode behind sheet of paper

摘要

An arrangement (16) of the electrodes (19) in the space between the toner particle carrier (17) and the counter-electrode (12) opens and closes passages for the force of attraction between them. When particles (9) are transferred to the paper (23), an equipotential distribution (6) is obtd. with the boundary electrodes out of range of the electric field. Pref. when no development takes place the air in the intervening space is charged with positive and/or negative ions to neutralise the electrostatic attraction and/or to achieve an homogeneous charge density over the electrode surface layer. ADVANTAGE - Distinct lines are achieved without blurred edge regions, and uniform quality is maintained over entire printed sheet.