Patent ID: 9116454
Filing Date: 2015-08-25
Classification: G03G

Abstract:
1. A density detection apparatus comprising: an image forming unit configured to form a plurality of density detection images having different area ratios on an image carrier; a measuring unit configured to measure a first amount of light reflected by the image carrier before the plurality of density detection images are formed thereon and configured to measure a second amount of light reflected by the plurality of density detection images formed on the image carrier; a storage unit configured to store, as a reference value, the first amount of light reflected by the image carrier during one revolution of the image carrier before the plurality of density detection images are formed thereon; a determining unit configured to determine, each time a density correction processing is started, a threshold corresponding to the plurality of density detection images on the basis of the reference value; and a density obtaining unit configured to obtain, based on the determined threshold, a respective plurality of density levels corresponding to the plurality of density detection images, wherein the determining unit is configured to specify a position of the image carrier at which a difference between the reference value and an average value of the first amount of light is large during one revolution of the image carrier, and configured to cause the density detection apparatus to repeat the density correction processing by (i) causing the image forming unit to form the plurality of density detection images having different area ratios on the image carrier, (ii) causing the measuring unit to measure the second amount of light reflected by the plurality of density detection images formed on the image carrier, and (iii) determining the threshold corresponding to the plurality of density detection images so that a change in the amount of light reflected by one of the density detection images located at the specified position will be equal to or smaller than a predetermined permissible value.