Patent ID: 8538581

Claim:
An article rental machine for authenticating a returned article comprising a machine-readable authentication code forming a first layer on a surface of the returned article, and a second layer substantially opaque in visible light and at least partially overlaying the authentication code, the article rental machine comprising: a receptacle for receiving the returned article; an infrared light source configured to illuminate the surface of the returned article with electromagnetic radiation in an infrared spectrum; an article sensor in communication with the infrared light source, wherein the article sensor detects a presence of the returned article and causes the infrared light source to illuminate; an image capture device configured to capture a digital image of the authentication code while the surface of the returned article is illuminated, wherein the authentication code is comprised of a carbon-containing ink visible in the infrared spectrum, and the second layer is comprised of a substantially carbon-free ink; and a processor in communication with the image capture device, wherein the processor is configured to identify the authentication code from the digital image and to compare the authentication code to a master authentication code.