Method and apparatus for improving gray scale resolution in an ink jet printing system

摘要

Image processing apparatus for increasing the gray scale resolution of a graphic generated by an ink jet printing system wherein the graphic is made up of pixel areas on a receiving surface and each pixel area is comprised of a fixed number of potential dot positions printed with substantially equal sized dots. A sequential series of image density signals representative of the gray scale color intensity is generated from an original graphic and converted to a dot level value for each pixel. A pixel's dot level value is compared to a set of integer and non-integer values and pixels having dot level values falling between the same two successive integer values are selected. A predetermined dot level value is alternately added to the identified adjacent pixels so that one is increased and the other is decreased by the predetermined dot value. The resulting values are rounded off to the nearest integer and each pixel is printed with its respective new value. The resulting gray scale color intensity represented by the two printed pixels is the average of the sums of the two printed pixels' dot level values.