Patent ID: 9457561
Filing Date: 2016-10-04
CPC Classification: B41J,H04N

Claim Text:
1. An image forming apparatus, comprising: an image forming device including a recording head with nozzles to discharge a droplet to form an image on a recording medium; a threshold comparator configured to compare a pixel value corresponding to a defective discharge nozzle, from which a droplet is not normally discharged, and a predetermined threshold; a first image compensator configured to execute a processing of, for at least a pixel value less than the predetermined threshold among pixel values corresponding to defective discharge nozzles, setting a value of stopping discharge of a droplet from a defective discharge nozzle in converting multi-valued data of an input image into n-value data, where n is an integer of two or greater, and spreading a quantization error due to setting of the value of stopping discharge in converting the multi-valued data of the input image into the n-value data, to neighboring pixels of a pixel corresponding to a defective discharge nozzle; and a second image compensator configured to execute a processing of replacing a smaller dot among dots around the defective discharge nozzle with a larger dot by pattern matching with use of a predetermined mask pattern in accordance with a dot size and placement around the defective discharge nozzle, on condition that as a result of comparison of the threshold comparator, the pixel value corresponding to the defective discharge nozzle is equal to or more than the predetermined threshold.