Patent ID: 9083911
Filing Date: 2015-07-14
Classification: B41J,H04N

Abstract:
1. A nozzle shading method applicable to nozzles of an inkjet printing apparatus, comprising: a reading step for repeatedly reading charts for shading correction with a contact image sensor (CIS) type scanner with a plurality of read conditions consisting of varied exposure amounts, while emitting light from light emitters, thereby to obtain a plurality of image data with different read conditions; a density value converting step for converting luminance values of the plurality of image data read with the plurality of read conditions consisting of the varied exposure amounts into density values, respectively, based on a luminance value to density value conversion table corresponding to each of the plurality of read conditions consisting of the varied exposure amounts; a correction table creating step for creating nozzle shading correction tables corresponding to all input tone values, based on target density values for correction which are the plurality of density values converted and combined with density values having a region where detection of the density values is saturated; and a shading correcting step for carrying out shading correction based on the correction tables.