Abstract: As a thinning pattern which is used in a multipass recording method, plural mask patterns are created according to a printing mode from a pseudo periodic mask arrangement that an arrangement of non-recording pixels and recording pixels becomes visually preferable when binarization is performed at an arbitrary level. Thus, as compared with a mask pattern based on a random number, generation of a repetitive pattern and deterioration of graininess can be lowered, and the number of memories for storing the mask patterns can be reduced.

Abstract: A color ink-jet head, having plural arrays of nozzles side by side in a main scan direction corresponding to different color inks, is moved to scan reciprocally. In a multi-pass recording for divided recording on an area by scanning at plural times with the head, an ink firstly landed on recording of the area determines a prioritized color influential on the color tone. Moreover, a printing medium is largely covered by the recording of first two passes. A harmful influence on a whole image by the color irregularity can reduced by suppressing the color irregularity in the two passes, therefore, the data recording ratio of the first pass to the area is set smaller than that of the second pass and thereafter. Further, for such the control, a pseudo periodical masking data arranging record prohibiting pixels and record permitting pixels in a visually agreeable state is introduced.

Abstract: An image processing method matches the gradations of a first output unit and a second output unit which have different gradation-reproduction ranges. The image processing method sets first-output-unit information on the first output unit, sets output-medium information for use in the second output unit, and finds an output-gradation reproduction curve from the first-output-unit information and the output-medium information.

Abstract: A color ink-jet head, having plural arrays of nozzles side by side in a main scan direction corresponding to different color inks, is moved to scan reciprocally. In a multi-pass recording for divided recording on an area by scanning at plural times with the head, an ink firstly landed on recording of the area determines a prioritized color influential on the color tone. Moreover, a printing medium is largely covered by the recording of first two passes. A harmful influence on a whole image by the color irregularity can reduced by suppressing the color irregularity in the two passes, therefore, the data recording ratio of the first pass to the area is set smaller than that of the second pass and thereafter. Further, for such the control, a pseudo periodical masking data arranging record prohibiting pixels and record permitting pixels in a visually agreeable state is introduced.

Abstract: As a thinning pattern which is used in a multipass recording method, plural mask patterns are created according to a printing mode from a pseudo periodic mask arrangement that an arrangement of non-recording pixels and recording pixels becomes visually preferable when binarization is performed at an arbitrary level. Thus, as compared with a mask pattern based on a random number, generation of repetitive pattern and deterioration of graininess can be lowered, and the number of memories for storing the mask patterns can be reduced.

Abstract: An image processing apparatus of a digital copying machine, a digital facsimile, or a printer comprises an input unit to input multi-level data; an arithmetic operating circuit for adding error data to the input multi-level data and for calculating error correction data; a selector to select a predetermined dot pattern on the basis of the error correction data; an error calculation circuit to calculate a difference between the representative value for each dot pattern and the error correction data; a storage memory for storing the difference as error data into a memory; and a dot pattern memory in which dot patterns corresponding to a plurality of colors have been stored. The input unit inputs multi-level image data of a plurality of colors and the selector selects the dot pattern whose dot arrangement differs in accordance with the color of the multi-level image data.

Abstract: An image processing apparatus of a digital copying apparatus, digital facsimile, printer, or the like comprises an input unit to input multi-level data, an arithmetic operation circuit for adding error data to the input multi-level data and calculating error correction data, a selector to select a predetermined dot pattern on the basis of the error correction data, an error calculation circuit to calculate a difference between a representative value for each dot pattern and the error correction data; and a storing circuit for storing the difference as error data into a memory. The selector comprises a level classification threshold value storage memory in which threshold values to classify the error correction data into levels have been stored, and a data level determination circuit for classifying the error correction data into levels on the basis of the value of the error correction data and the value stored in the level classification threshold value storage memory.