Developer roll

摘要

This invention relates to image developing apparatus and specifically a developer roll for use in combination with a color producing substrate. In accordance with this invention, a color is formed by the reaction of isolated chromogenic materials. A first chromogenic material is typically a color precusor of the electron donating type whereas the second chromogenic material is typically identified as a color developer and is generally of the electron accepting type. In this invention a developer roll bunishes the active coating on the color producing substrate to promote the reaction of the color forming ingredients. This developing action is accomplished without "rupturing pressure" or without the necessity for pressure rollers which define a pressure nip.