Abstract: An apparatus for connecting electrical power to an exposure lamp in an image scanner in response to the detection of ambient light by a light sensor located under the scanner's cover. Such an apparatus provides an apparent reduction in exposure lamp warm-up time, with associated improvement in operator productivity, while minimizing exposure lamp operational life degradation and excessive energy consumption caused by leaving the exposure lamp turned on. Once the exposure lamp is turned on, a timing circuit is used in the preferred embodiment to disconnect electrical power from the exposure lamp so that if the scanner's cover is left open or closed, the exposure lamp will not be left on for excessively long periods of time.