Time indicator

摘要

A time indicator is provided which includes a first substrate having first and second surfaces and at least two indicia areas on the first surface. A second substrate having first and second surfaces is also provided. A first chemical agent is provided on each of the indicia areas and a second chemical agent is provided on the first surface of the second substrate. The first surfaces of each substrate overlay and are in contact with each other, the chemical agents coacting to cause a visually perceptible change at one of the second surfaces overlaying the first indicia area in a first selected time interval and a visually perceptible change in said second surface overlaying the second indicia area in a second selected time interval, the first selected time interval differing from the second selected time interval. A preferred embodiment of the time indicator includes an ink pattern of dots printed in a preselected pattern in the indicia area and an adhesive activator means on the first surface of the second substrate. The ink and activator coact to cause the ink pattern of dots to gradually bleed and blend together to cause a visually perceptible change through the second substrate overlaying the indicia area in a selected time interval. Preferred embodiments of the invention are self-timing parking permits and tickets.