Patent ID: 6568780
Filing Date: 2003-05-27
Classification: B41J

Abstract:
An environmental condition detection system for a hardcopy device, comprising: an environmental condition sensor having an optical property which changes in response to a change in an environmental condition, said environmental condition sensor comprising a base material treated with a solution of a color-changing material which changes color in response to said change in said environmental condition, said base material being of an absorbent material having a first region which has absorbed said solution having a first concentration of said color-changing material, and a second region which has absorbed said solution having a second concentration of said color-changing material, with said second concentration being different from said first concentration, and with said first region changing color in response to a first change in said environmental condition, and said second region changing color in response to a second change in said environmental condition different from said first change; and an optical sensor which detects said change in the optical property and generates a signal in response thereto.