| 摘要 |
PURPOSE:To contrive to miniaturize the titled reader by using a heat from a drive resistor of a stepping motor causing internal temperature rise for preheating a fluorescent light, thereby eliminating the need for a preheater or a self-control heat element. CONSTITUTION:When a tube wall temperature of a fluorescent light detected by a temperature detection element 6 is lower than the tube wall temperature at which the lighting efficient of the light source is maximum and the standard spectrum distribution characteristic of the light source is obtained and the stimulated luminous quantity of the light source is 80% or over the maximum stimulated luminous quantity, a resistor selection circuit 12 controls the 1st stepping motor drive resistor 7 so as to be connected to a power supply 11 by an output of a comparator 10. Thus, the current driving the stepping motor 14 flows through the 1st stepping motor drive resistor 7 and the fluorescent light 2 is heated quickly by the heat generated in the 1st stepping motor drive resistor 7.
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