Printing apparatus and method thereof

A printing method, in which an image is formed on a printing medium by that a print head having a plurality of printing elements moves in two orthogonal directions, that is, a main scanning direction and a sub scanning direction, comprising the steps of:

• selecting printing elements to be used for printing from said plurality of printing elements;
• dividing said selected printing elements into P pieces, where P is an integer of two or more, of printing element groups in which the number of printing elements m in each of said P pieces of printing element groups is equal;
• allocating one of said P pieces of printing element groups to each of a plurality of printing pixels to be printed in said main scanning direction;
• and
• setting a scanning amount in said sub scanning direction so that one of said printing elements in each of said plurality of P pieces of printing element groups corresponds to one of said plurality of printing pixels in said sub scanning direction for printing all of said plurality of printing pixels in said sub scanning direction on said printing medium,
• wherein said scanning amount in said sub scanning direction is m×d, where d is a pitch of said printing pixels, and said m has no prime factors greater than one in common with w/d, where w is a pitch of said printing elements.

A printing apparatus that forms an image on a printing medium by a print head, which moves in a main scanning direction, and by movement of the printing medium relative to the print head in a sub scanning direction, which is orthogonal to the main scanning direction, comprising:

• a print head including a plurality of printing elements that are disposed in a straight line in the sub scanning direction and equally spaced with a pitch, w, wherein each of the plurality of printing elements prints a printing element line having a predetermined number of pixels;
• a number of groups, P, of the plurality of printing elements that equals a number of printing scans of a shingling process, wherein
• P is an integral number of 2 or more,
• each of the printing element lines is subject to P printing scans and is divided into a number of arrays of printing pixels, each of the number of arrays of printing pixels corresponding to one of the number of groups, P, of the plurality of printing elements,
• each group of the plurality of printing elements has an equal number, m, of printing elements, and
• the movement of the printing medium in the sub scanning direction is an integral multiple, m, of d, where d is a pitch of the printing pixels in the sub scanning direction and the m has no prime factors greater than one in common with w/d, to produce an interleaved constant scanning amount such that at least one of the plurality of printing elements subjects each pixel of each of the printing element lines to a printing scan.

A printing method that forms an image on a printing medium by a print head, which moves in a main scanning direction, and by movement of the printing medium relative to the print head in a sub scanning direction, which is orthogonal to the main scanning direction, comprising:

• selecting a number of groups, P, of a plurality of printing elements of the print head, disposed in a straight line in the sub scanning direction, that equals a number of printing scans of a shingling process, wherein P is an integral number of 2 or more and each group of the number of groups, P, of the plurality of printing elements has an equal number, m, of printing elements;
• dividing each of a plurality of printing element lines into a number of arrays of printing pixels, corresponding to one of the number of groups, P, of the plurality of printing elements;
• and
• moving the printing medium in the sub scanning direction an integral multiple, m, of d, where d is a pitch of the printing pixels in the sub scanning direction and the m has no prime factors greater than one in common with w/d, to produce an interleaved constant scanning amount such that at least one of the plurality of printing elements subjects each pixel of each of the printing element lines to a printing scan.