| 摘要 |
PURPOSE:To eliminate the need for a heater and to prolong the life of a fluorescent lamp by holding the fluorescent lamp at constant temperature with the heat that it generates according to detected temperature and providing certain width between 1st set temperature and 2nd set temperature for operation control. CONSTITUTION:A thermistor 7 as a temperature detector for the fluorescent lamp 4 is arranged closely on the opposite back surface of the fluorescent lamp 4 from a document platen. Further, the 1st set temperature A and 2nd set temperature B are set so as to control the operation of the fluorescent lamp 4 according to the detected temperature. The thermistor 7 detects the temperature of the fluorescent lamp 4 and a temperature control means(CPU) drives the fluorescent lamp 4 when the detected temperature is lower than the set temperature A. The fluorescent lamp 4 heats itself by lighting. When the detected temperature of the thermistor 7 reaches the set temperature A, the fluorescent lamp 4 is turned off and when the temperature falls to the set temperature B, the fluorescent lamp is turned on. Further, the certain width is given between the set temperature A and set temperature B to decrease the frequency of the turning-ON/OFF operation of the fluorescent lamp 4. |
