Halftone Dot Formation Method and Apparatus for Reducing Layer Thickness of Coloring Material Inside Halftone Dots, and Image Formation Apparatus

Abstract

An image processing method generates a halftone-dot image by forming a halftone dot, which is represented by a set of one or plural output dots and corresponds to an intensity of an input image signal, while making a part of the dots constituting the halftone dot to be an actual non-output dot so as to reduce an amount of a coloring material of the halftone-dot portion. When the intensity of the image signal exceeds a predetermined value and is in a predetermined range, while maintaining contour dots, which are output dots contribute to formation of a contour of the halftone dot, to be the output dot, the image processing method makes a part of dots inside the contour dots to be the actual non-output dot.

1 . An image forming apparatus for generating a halftone-dot image by forming a halftone dot, which is represented by a set of one or plural output dots and corresponds to an intensity of an input image signal, while making a part of the dots constituting the halftone dot to be an actual non-output dot so as to reduce an amount of a coloring material of the halftone-dot portion, the image processing apparatus comprising:
 a binarization processing section that, when the intensity of the image signal exceeds a predetermined value and is in a predetermined range, while maintaining contour dots, which are output dots contribute to formation of a contour of the halftone dot, to be the output dot, makes a part of dots inside the contour dots to be the actual non-output dot; and   an image recording section that forms the halftone-dot image including the actual non-output dot in the halftone dot, on a basis of the binarized data generated by the binarization processing section.   
     
     
         2 . The image forming apparatus according to  claim 1 , further comprising:
 a first halftone-dot image generating section that generates binarized data representing the halftone dot, which is represented by the plural dots and corresponds to the intensity of the input image signal;   a second halftone-dot image generating section that generates binarized data representing a set of the real non-output dot in response to the intensity of the image signal exceeding the predetermined value; and   a calculation processing section that makes the part of dots inside the contour dots to be the non-output dot on a basis of the binarized data, which is generated by the first halftone-dot image generating section and represents the halftone dot, and the binarized data, which is generated by the second halftone-dot image generating section and represents the set of real non-output dot, wherein:   the image recording section comprises a recording energy control section that executes image recording on a basis of the binarized data, which is generated by the calculation processing section and makes the part of dots inside the contour dot be the non-output dot.   
     
     
         3 . The image forming apparatus according to  claim 1 , further comprising:
 a first halftone-dot image generating section that generates binarized data representing the halftone dot, which is represented by the plural dots and corresponds to the intensity of the input image signal; and   a second halftone-dot image generating section that generates binarized data representing a set of the real non-output dot in response to the intensity of the image signal exceeding the predetermined value, wherein:   the image recording section comprises:   a modulation control section that generates output modulation data with using the binarized data, which is generated by the first halftone-dot image generating section and represents the halftone dot, as an on/off control input and using the binarized data, which is generated by the second halftone-dot image generating section and represents the set of real non-output dot, as a modulation control input; and   a recording energy control section that executes image recording on a basis of the output modulation data generated by the modulation control section.