| 摘要 |
<P>PROBLEM TO BE SOLVED: To stably reproduce an isolated dot or the like without correcting image data of a print object. <P>SOLUTION: Isolated dots at a given interval P are formed on an intermediate transfer belt 112, and the density of the dots is detected by a toner density sensor 130. A detection signal of the toner density sensor 130 is subjected to frequency analysis. In the results of the frequency analysis, for example, a value of a peak Cp in a basic frequency component is compared to a threshold Th. If the value of the peak Cp is lower than the threshold Th, reproduction of isolated dots is determined as unstable. In this case, an exposure time of the isolated dots is increased by a unit time duration; and again isolated dots at the given interval P are formed, the density detection signal of the dots is subjected to frequency analysis, and the peak value in the results of the frequency analysis is compared to the threshold Th. The exposure time is increased in a stepwise manner until the peak value reaches the threshold Th or higher. When the peak value reaches the threshold Th or higher, reproduction of the isolated dots is determined as stabilized and the process is terminated. <P>COPYRIGHT: (C)2012,JPO&INPIT |
