| 摘要 |
PURPOSE:To decrease overshooting quantity at the tube wall temperature and stabilize optical output of the captioned device, by disposing around a discharge lamp two groups of heater elements which are connected in parallel and by on- off controlling each group in each different temperature range. CONSTITUTION:When heating a fluorescent lamp used for an exposure lamp or the like of a copying machine, 1st and 2nd heater elements 6, 7 are buried in parallel in an insulating material installed around said lamp and these elements 6, 7 are on-off controlled in individually different temperature ranges by means of 1st and 2nd thermostats 8, 9 mounted on the lamp tube wall. Consequently, in a low temperature environment and soon after a power source is actuated, the lamp is rapidly heated by the two heater elements 6, 7, the temperature of the tube wall is raised up to a temperature which is a little lower than optimum temperature of 40 deg.C, one of said heater elements is turned off, and the other is forced by control the temperature and by doing that the overshooting quantity can be decreased and a stable optical output can be obtained. |
