Patent ID: 7510258
Filing Date: 2009-03-31
Classification: B41J

Abstract:
1. A method of detecting the alignment of print heads relative to one another in an ink jet printer having a plurality of print heads arranged side by side on a carriage in a first direction (Y), each print head having a conductive nozzle plate which defines an edge that extends in said first direction (Y), wherein a sensor is used for determining the position of a reference mark formed on the print head, said sensor being used to measure a capacitance between the nozzle plate serving as the reference mark, and the sensor, said alignment detection comprising the steps of moving the carriage relative to the sensor in said first direction (Y) into a first position (“b”) where said sensor extends across said edge of one print head, and into a second position (“d”) where said sensor extends across the edge of another print head, measuring the capacitances in said first and second positions, and comparing the measured capacitances, thereby determining the relative position of said print heads in a second direction (X) orthogonal to said first direction (Y).