Method of printing test pattern and printing apparatus for the same

A printing apparatus that drives a print head to create dots while carrying out a main scan, which moves said print head forward and backward relative to said printing medium in a main scanning direction, said printing apparatus carrying out a sub-scan that moves said printing medium relative to said print head in a sub-scanning direction, which is perpendicular to the main scanning direction, thereby printing an image on said printing medium, said printing apparatus comprising:

• a forward-course pattern formation unit that drives said print head at a first timing that forms a first pattern in the course of the main scan in the forward direction, wherein said first pattern comprises a dark portion having a certain area and a light portion having an area greater than the area of said dark portion that alternately appear at a first cycle in the main scanning direction in a predetermined first section of said printing medium;
• and
• a backward-course pattern formation unit that drives said print head at a second timing that are supposed to form a second pattern in the course of the main scan in the backward direction, wherein said second pattern comprises a dark portion having a certain area and a light portion having an area greater than the area of said dark portion that alternately appear at a second cycle in the main scanning direction in a predetermined second section of said printing medium, said predetermined second section at least partly overlapping said predetermined first section, and wherein said dark portion of said first pattern and said dark portion of said second pattern appear at a fixed interval in the main scanning direction in said overlapped area.

In a printer that creates dots while carrying out a main scan, which moves a print head forward and backward relative to a printing medium, a method of designing a test pattern formed by the main scan both in the forward direction and in the backward direction,

• wherein said test pattern comprises a plurality of dots created at a predetermined interval in a predetermined area,
• said method comprising the steps of:
• specifying a spatial frequency that gives a maximum visual sensitivity of a human's eye with respect to lightness;
• and
• determining said predetermined interval of said dots, in order to cause a spatial frequency of said test pattern to be substantially equal to said specified spatial frequency.

A recording medium on which a program for driving a print head and forming a test pattern, which comprises a plurality of dots, on a printing medium is stored in a computer readable manner,

• said program comprising:
• a first program code unit that causes a computer to realize a function that drives said print head at a first timing that forms a first pattern in the course of a main scan in a forward direction, wherein said first pattern comprises a dark portion having a certain area and a light portion having an area greater than the area of said dark portion that alternately appear at a first cycle in the main scanning direction in a predetermined first section of said printing medium;
• and
• a second program code unit that causes the computer to realize a function that drives said print head at a second timing that forms a second pattern in the course of the main scan in a backward direction, wherein said second pattern comprises a dark portion having a certain area and a light portion having an area greater than the area of said dark portion that alternately appear at a second cycle in the main scanning direction in a predetermined second section of said printing medium, said predetermined second section at least partly overlapping said predetermined first section, and wherein said dark portion of said first pattern and said dark portion of said second pattern appear at a fixed interval in the main scanning direction in said overlapped area.