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Printing apparatus and printing method

  • US 9,944,071 B2
  • Filed: 03/06/2015
  • Issued: 04/17/2018
  • Est. Priority Date: 03/07/2014
  • Status: Active Grant
First Claim
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1. A printing apparatus for performing printing on a medium in an inkjet method, comprising:

  • a head unit having a plurality of nozzles for ejecting ink drops onto the medium;

    a main scan driver configured to drive the head unit to perform main scan operations of ejecting ink drops from the nozzles while moving in a main scan direction which is predetermined; and

    a controller configured to control operations of performing printing on the medium by controlling the main scan operations of the head unit and the main scan driver,wherein, when the main scan operations are performed, the controller performs control with respect to each area of the medium such that the head unit ejects ink drops of one selected color onto a plurality of first selection pixels selected on a basis of a first mask data item and a plurality of second selection pixels selected on a basis of a second mask data item different from the first mask data item in an arrangement of a plurality of pixels to be selected,wherein, printing on the plurality of first selection pixels and the plurality of second selection pixels is performed by a plurality of main scan operations to be performed with respect to a same position,a spatial frequency characteristic of a pixel arrangement of the plurality of second selection pixels is different from a spatial frequency characteristic of a pixel arrangement of the plurality of first selection pixels,in a first pattern of the first mask data item and a second pattern of the second mask data item, a spatial frequency characteristic of one of the first pattern and the second pattern is one-sided on the high frequency side, and a spatial frequency characteristic of the other one of the first pattern and the second pattern is one-sided on the low frequency side,a pattern that is one-sided on the high frequency side is a distance at which spatial frequencies corresponding to 80% or more of all inter-dot distances are higher than a peak frequency of a visual sensitivity function,a pattern that is one-sided on the low frequency side is a distance at which the spatial frequencies corresponding to 80% or more of the all inter-dot distances are lower than the peak frequency of the visual sensitivity function.

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