| 摘要 |
<p>PROBLEM TO BE SOLVED: To obtain an exposure controller in which erroneous emission of light from a light emitting element due to offset voltage can be prevented. SOLUTION: A photodiode 228 detects the quantity of light being emitted from each LED chip 208R, 208G, 208B when 0 V is applied to each double stage sample hold circuit. An offset voltage is then determined for each double stage sample hold circuit from the detected quantity of light. The conversion table of a lock-up table 12 for converting an image data inputted from an image memory 10 according to a specified rule and delivering the converted data to a DA converter 32 is previously rewritten such that the offset voltage of each double stage sample hold circuit thus determined can be canceled by adding a specified voltage to the output from the DA converter 32 through an offset adder circuit 14.</p> |
