| 摘要 |
<P>PROBLEM TO BE SOLVED: To realize excellent gradation control regardless of the number of the levels of input signals in an image forming apparatus, its gradation control method and a printing system. <P>SOLUTION: The image forming apparatus is equipped with a photoreceptor drum 1 on which a latent image corresponding to an image signal is formed, an image transfer body to which a visible image based on the latent image is transferred, a density detection sensor 13 for detecting the density of the visible image, a conversion means for forming a γ conversion table by reading a plurality of patch patterns formed in different density by the sensor 13, and a control means for controlling the gradation of an output image by using the γ conversion table. The apparatus is equipped with a reference density forming means for forming the patch pattern in the specified density being reference on the image transfer body and a comparison means for comparing the density of the patch pattern read by the sensor 13 with the reference density. Then, the γ conversion table is formed so that image density characteristic is different from the signal level of the γ characteristic of the reference according to the result of comparison, and the gradation control is performed by using the γ conversion table. <P>COPYRIGHT: (C)2003,JPO |
