Patent ID: 8147038
Filing Date: 2012-04-03
Classification: B41J

Abstract:
1. An image forming apparatus, comprising: a first group of large nozzles which eject large droplets of the liquid for a color; a second group of small nozzles which eject small droplets of the liquid for the color, the small droplets having volume smaller than the large droplets; a dot data creation device which creates dot data according to input image data; a dot data correction device which corrects the dot data if there is an abnormal nozzle in one of the first and second groups, in such a manner that a corrective nozzle is selected from the other of the first and second groups, and droplet ejection performed by the corrective nozzle substitutes for droplet ejection that is originally to be performed by the abnormal nozzle; and a driving device which drives the large and small nozzles to eject the large and small droplets according to the corrected dot data, wherein: the dot data correction device corrects the dot data if the abnormal nozzle belongs to the second group, in such a manner that a total amount of the liquid ejected by the corrective nozzle is greater than a total amount of the liquid that was originally to be ejected by the abnormal nozzle; the dot data correction device controls ink-droplet ejection such that the large droplets are ejected and deposited onto a porous surface of paper to form large dots on the paper, and the small droplets are ejected and deposited onto the porous surface of the paper to form small dots on the paper; and wherein the dot data correction device corrects the dot data taking into account that the volume of each of the large droplets is x times the volume of each of the small droplets, and so that the dot data correction device corrects the dot data if the abnormal nozzle belongs to the second group, in such a manner that one large dot substitutes for y small dots, where 1<y<x.