Patent ID: 6527358
Filing Date: 2003-03-04
Classification: B41J

Abstract:
A printing apparatus which performs printing by discharging ink onto a print medium while scanning a printhead, based on an ink-jet method, having a plurality of printing elements, said apparatus comprising:scan means for scanning said printhead; print means for performing print operation by using said printhead; test discharge means for controlling operation of said printhead to select at least a part of said plurality of printing elements and perform test ink discharge while said scan means scans said printhead; detection means for detecting ink-discharge statuses of said plurality of printing elements of said printhead from the test ink discharge by said test ink discharge means; and first control means for controlling said test discharge means to sequentially select said printing elements of said printhead at each of plural scannings of said printhead by said scan means, and controlling said detection means to detect the ink-discharge statuses, wherein said detection means includes: light emission means for emitting a light beam; and photoreception means for receiving said light beam, wherein said printhead is provided such that ink droplets discharged from said plurality of printing elements block said light beam, wherein said light emission means and said photoreception means are provided such that a light axis of said light beam intersects an array direction of the plurality of printing elements of said printhead, thereby detecting ink discharge status of a part of the plurality of printing elements, and wherein said plurality of printing elements selected by said test discharge means are determined based on a distance between said plurality of printing element arrays, a moving speed of said printhead, the number of printing elements consisting said plurality of printing element arrays, the length of printing by each of said plurality of printing element arrays, a printing resolution in a printhead scanning direction, an ink discharge period in the printhead scanning direction, and a distance between said printing elements of said printing element arrays.