Automatic developing apparatus for photosensitive lithographic printing plates

Abstract

An automatic developing apparatus for photosensitive lithographic printing plates, includes a development vessel storing a plate developer and a replenishing apparatus for replenishing a predetermined amount of development replenisher in accordance with an electric conductance of the plate developer. The replenishing apparatus includes: an electric conductance sensor detecting the electric conductance of the plate developer; a delivery device delivering the development replenisher into the development vessel; a timer detecting an elapsed time from replenishment of the development replenisher; and a control device for setting a reference electric conductance and for controlling the delivery device to replenish the development replenisher when the detected electric conductance has fallen below the set reference electric conductance. The control device calculates a carbon dioxide exhaustion replenisher ratio for replenishing the development replenisher in accordance with the elapsed time and the predetermined amount of the development replenisher. The automatic developing apparatus is capable of maintaining the activity of the plate developer in a good condition over a long period of time by the ratio between the plate processing exhaustion and the carbon dioxide exhaustion.

Dependencies are inferred from the claim text.