Liquid developing apparatus
AssigneeXerox Corporation
InventorWilliam A. Lloyd
Life of this patent
Estimating the term…
Abstract
A liquid developing apparatus is provided for developing, with a liquid developer or toner, an electrographic latent image formed on an image bearing, charge retaining surface of a moving recording medium and thereafter wiping excess developer from the medium surface. The apparatus is designed to require only a single developer/wipe roll to perform the dual function of image development surface wiping. The single developer/wipe roll is supported for rotational movement in a direction opposite to the direction of movement of the recording medium and is in forward and leeward tangential engagement with a portion of the moving medium surface, respectively, to form a development apex and fluid seal between it and the recording medium surface and to wipe the recording medium surface to promote surface drying.
Claims17
A liquid development apparatus for developing with a liquid developer and wiping excess developer from an electrographic latent image formed on an image bearing, charge retaining surface of a moving recording medium comprising:
- a roll supported for rotational movement in tangential engagement with the surface of said recording medium forming a development apex between the surface of said roll and said recording medium, the circumference of said roll sufficiently large to provide a tangential engaging surface with said recording medium surface,
- a baffle plate supported in spaced relation to said roll and positioned upstream from said roll relative to said moving recording medium for receiving a flow of said liquid developer between it and said roll and directing said liquid developer into said development apex to form a meniscus with the surface of said recording medium, the top of said baffle plate spaced from said recording medium surface to form an outlet for liquid developer from said development apex over the top of said plate,
- said roll rotated in a direction against the direction of movement of said recording medium to form a fluid seal between the surface of said roll and said medium to prevent liquid developer from passing therebetween,
- said tangential engaging surface against said medium movement comprising a first portion of forward tangential engagement with the surface of said recording medium to form said fluid seal with said recording medium surface and to force expended liquid developer in said development apex toward said outlet and a second adjacent portion of leeward tangential engagement with the surface of said recording medium to wipe said recording medium surface.
In a developing apparatus for developing electrographic images formed on a surface of a recording medium as the recording medium is moved relative to engagement with said apparatus and comprising:
- a rotatably supported developer roll rotated in a direction opposed to the direction of movement of said recording medium and positioned in tangential engagement with said recording medium surface to form a development apex between the circumferential surface of said roll and said recording medium surface,
- means to pump developer directly from an inlet passage into and along the full length of said formed development apex and form a meniscus with said recording medium surface during the active pumping of said developer,
- means to guide excess or expended developer away from said development apex in an opposite direction to medium movement to an outlet passage,
- means to form a wrap angle of said medium surface in tangential engagement with said roll of sufficient wrap length, and in conjunction with said opposed movement, to form at its forward extent a fluid seal at the rearward tip of said development apex and to form at its leeward extent a wiping action on said recording medium surface,
- said opposed rotational movement of said developer roll functioning to breakup and sweep away said meniscus upon cessation of pumping of said developer.
Dependencies are inferred from the claim text.