Patent ID: 8764151

Claim:
A method for processing image data to preserve edges comprising: identifying edge image data values in a plurality of image data values stored in a memory, the image data values stored in the memory are less than 100 percent of a maximum ink drop mass that can be ejected by inkjet ejectors in at least one printhead; excluding the identified edge image data values from dithering of the image data values stored in the memory; excluding image data values not identified as edge image data values from dithering, the excluded image data values not identified as edge image data values having a predetermined relationship to at least one edge image data value; dithering at least one image data value stored in the memory that was not excluded from dithering by determining whether to modify the at least one image data value that was not excluded with reference to a threshold and a predetermined percentage of the maximum drop mass, the threshold being greater than zero, but less than the predetermined percentage of the maximum ink drop mass; generating firing signals corresponding to the image data values stored in the memory; and operating the at least one printhead with the generated firing signals.