Abstract: An apparatus for inhibiting the copying of confidential documents is disclosed. Confidential documents are treated with an infrared ray-absorbing agent. The apparatus for inhibiting the copying of confidential documents is comprised of a means to detect the presence of the infrared ray-absorbing agent, and a means to stop a copying operation upon detection of the agent or a means to start a control system to make the documents unreadable. Documents may also be provided with a metal layer. The apparatus is then comprised of a means to detect the presence of the metal layer and a means to stop a copying operation or to start a control system adapted to make copied materials undistinguishable or unreadable upon detection of the metal layer.

Abstract: A coated paper suitable for use in an electrophotographic process for receiving an image formed by a magnetic brush device with a single component developer is disclosed. The paper is coated with a composition made of a styrene/butadiene latex and a crosslinking agent for the latex, together with any desired pigment and nonionic emulsifier. The composition may be economically coated onto paper at an amount about 1 to 5 grams per square meter.