Patent ID: 7826094

Claim:
An apparatus for processing data describing an image, the apparatus comprising: an input device that inputs the data including a sequence of pixel values, each pixel value describing tone of a corresponding one of pixels arranged in a scanning direction; a binarizing device that performs a binarizing calculation for each pixel based on the input data, wherein the binarizing device comprises: a flag determining device configured to accumulate the pixel values up to a processing pixel, to assign a printing-flag for the processing pixel when the accumulated value reaches a first predetermined value, to subtract a second predetermined value from the accumulated value when the accumulated value reaches the first predetermined value, and to assign a nonprinting-flag for the processing pixel when the accumulated value does not reach the first predetermined value, and a repeating device configured to repeatedly activate the flag determining device by advancing the processing pixel along the scanning direction, a correcting device that corrects the accumulated value in order to reduce occurrence of the printing-flag when the nonprinting-flag is assigned to a second preceding pixel, the printing-flag is assigned to a first preceding pixel and the nonprinting-flag is assigned to the processing pixel, wherein the second preceding pixel is adjacent to the first preceding pixel and the first preceding pixel is adjacent to the processing pixel; a driving pulse generating device that generates driving pulses based on the flags assigned to the pixels; and an adjusting device that elongates the driving pulse for the first preceding pixel in order to make a printing dot longer when the nonprinting-flag is assigned to the second preceding pixel, the printing-flag is assigned to the first preceding pixel and the nonprinting-flag is assigned to the processing pixel; wherein an amount of correction of the accumulated value and a magnitude of elongation of the driving pulse are determined so that the reduced printing-flag occurrence cancels and effect of the elongation of the printed dot on the tone of images.