Grouped stylus electrostatic recording head

Claim 1

An electrostatic recording device for producing an image on an associated record carrier comprising: means for producing gray tones including a plurality of elongated recording electrodes for the formation of a latent recording in the form of a dot by each electrode when a high voltage is applied to said recording electrodes, each of said elongated recording electrodes comprising a plurality of sub-electrodes which are electrically insulated with respect to each other; each of said sub-electrodes being spaced from each adjacent sub-electrode a distance which is less than the minimum distance to produce an image on the associated carrier which will have the appearance of a continuous unbroken image when viewed at a normal reading distance, at least one sub-electrode from one recording electrode being electrically connected to at least one sub-electrode from another recording electrode, said sub-electrodes which are electrically connected constituting a group, said device further including switching means for selective switching voltage on each group independently of all other groups, at least two sub-electrodes in any of said recording electrodes being generally circular and disposed in generally concentric relationship, said device further including a generally square electrode disposed in generally coaxial relationship to each other sub-electrode in each of said recording electrodes at least at one axial portion thereof.