Lithographic plate processing apparatus

Claim 1

In a lithographic plate processing apparatus which comprises means for moving an exposed lithographic plate through the apparatus on an uphill slope, developer means within the apparatus for applying a developer liquid to the plate as it moves through the apparatus, and gumming means within the apparatus for applying gum to the plate after it has been developed, the developer means including a development enclosure through which the plate passes, a first scrub brush mounted inside the enclosure near the entrance on a horizontal axis for rotation in the direction of plate movement in scrubbing contact with the plate, first spray means for spraying developer liquid onto the exposed surface of the plate before it reaches the first scrub brush, a second scrub brush mounted inside the enclosure near the exit on a horizontal axis for rotation in the direction against the movement of the plate in scrubbing contact with the plate, a doctor blade engaging the second scrub brush for preventing developer liquid from being thrown forward by the rotation of the second scrub brush, and drainage means positioned beneath the enclosure between the first and second scrub brushes for removing dirty developer flowing from the plate, the improvement comprising, as part of the developer means, second spray means positioned within the enclosure and between the first and second scrub brushes for flowing clean developer liquid onto the exposed surface of the plate to simultaneously wash the dirty developer liquid from the plate and provide fresh developer on the plate as it is scrubbed by the second scrub brush.