Liquid developer apparatus

Claim 1

Liquid developer apparatus for developing an electrographic latent image formed on an image bearing surface of a recording medium with a liquid developer comprising a liquid carrier containing toning particles attractable to areas of said surface containing an image-wise charge of a first polarity comprising said latent image, said apparatus comprising a conductive applicator roll supported for rotational movement adjacent to the path of said recording medium forming a development gap therebetween, said applicator roll rotated in the direction of movement of said recording medium, a backrest electrode positioned on the opposite side of said recording medium to said applicator roll and across which said recording medium is drawn, a doctor blade supported against the surface of said applicator roll and positioned on the forward most position of said roll surface in the direction of the advancing recording medium, flow controlling means positioned between said doctor blade and said development gap and supported in spaced relation relative to said roll surface to form a metering gap, means to continually supply liquid developer to the surface of said applicator roll in a region between said doctor blade and said flow controlling means, means to rotate said applicator roll at high rotational velocity sufficient to produce a thin film of liquid developer on said roll surface and metered by said flow controlling means for forming a meniscus in said development gap relative to said moving recording medium, means to apply a voltage of said first polarity to said applicator roll, means to apply a voltage of a second polarity to said bakup electrode, a drying roll positioned down stream relative to the movement of said recording medium and supported for rotational movement against the surface of said recording medium, said dryer rotated in a direction opposite to the direction of movement of said recording medium to remove excess toning liquid from the surface thereof.