Patent ID: 6502920
Filing Date: 2003-01-07
Classification: B41J

Abstract:
An ink jet printing apparatus for forming a printed image on a print medium based on image data, comprising:a printer controller for receiving the image data and for generating print signals based on the image data; a print medium advance mechanism for causing the print medium to advance in a print medium advance direction based on print signals from the print controller; an ink jet print head having a plurality of ink ejection nozzles in a nozzle array and a corresponding number of ink heating elements, the print head for receiving the print signals and selectively activating the heating elements based on the print signals to cause ink to be ejected from the corresponding nozzles and onto the print medium as the print head scans across the print medium in a scan direction which is orthogonal to the print medium advance direction, thereby forming the image on the print medium, the nozzle array comprising: a first substantially columnar array of nozzles being aligned with a print medium advance direction which is perpendicular to the scan direction, the first array comprising: a first upper subarray pair comprising: a first upper left subarray of nozzles comprising a substantially linear arrangement of n number of nozzles having equal nozzle-to-nozzle spacings; and a first upper right subarray of nozzles comprising a substantially linear arrangement of n number of nozzles having equal nozzle-to-nozzle spacings, the nozzle-to-nozzle spacing in the first upper right subarray being equivalent to the nozzle-to-nozzle spacing in the first upper left subarray, the first upper right subarray being offset from the first upper left subarray in the scan direction by a first horizontal spacing and in the print medium advance direction by one-half of the nozzle-to-nozzle spacing; and a first lower subarray pair comprising: a first lower left subarray of nozzles comprising a substantially linear arrangement of n number of nozzles having equal nozzle-to-nozzle spacings, the first lower left subarray being offset from the first upper left subarray in the scan direction by twice the first horizontal spacing and in the print medium advance direction by n times the nozzle-to-nozzle spacing; and a first lower right subarray of nozzles comprising a substantially linear arrangement of n number of nozzles having equal nozzle-to-nozzle spacings, the nozzle-to-nozzle spacing in the first lower right subarray being equivalent to the nozzle-to-nozzle spacing in the first lower left subarray, the first lower right subarray being offset from the first lower left subarray in the scan direction by the first horizontal spacing and in the print medium advance direction by one-half of the nozzle-to-nozzle spacing; and a second substantially columnar array of nozzles being aligned with the print medium advance direction, the second array being offset from the first array in the scan direction by a second horizontal spacing and in the print medium advance direction by one-fourth of the nozzle-to-nozzle spacing. in the first upper subarrays, the second array comprising: a second upper subarray pair comprising: a second upper left subarray of nozzles comprising a substantially linear arrangement of n number of nozzles having equal nozzle-to-nozzle spacings, the nozzle-to-nozzle spacings in the second upper left subarray being equivalent to the nozzle-to-nozzle spacing in the first upper left subarray; and a second upper right subarray of nozzles comprising a substantially linear arrangement of n number of nozzles having equal nozzle-to-nozzle spacings, the nozzle-to-nozzle spacing in the second upper right subarray being equivalent to the nozzle-to-nozzle spacing in the first upper right subarray, the second upper right subarray being offset from the second upper left subarray in the scan direction by the first horizontal spacing and in the print medium advance direction by one-half of the nozzle-to-nozzle spacing; and a second lower subarray pair comprising: a second lower left subarray of nozzles comprising a substantially linear arrangement of n number of nozzles having equal nozzle-to-nozzle spacings, the nozzle-to-nozzle spacings in the second lower left subarray being equivalent to the nozzle-to-nozzle spacing in the first lower left subarray, the second lower left subarray being offset from the second upper left subarray in the scan direction by twice the first horizontal spacing and in the print medium advance direction by n times the nozzle-to-nozzle spacing; and a second lower right subarray of nozzles comprising a substantially linear arrangement of n number of nozzles having equal nozzle-to-nozzle spacings, the nozzle-to-nozzle spacing in the second lower right subarray being equivalent to the nozzle-to-nozzle spacing in the first lower right subarray, the second lower right subarray being offset from the second lower left subarray in the scan direction by the first horizontal spacing and in the print medium advance direction by one-half of the nozzle-to-nozzle spacing; and a print head scan mechanism for scanning the ink jet print head in the scan direction across the print medium.