Patent ID: 7413277
Filing Date: 2008-08-19
Classification: B41J

Abstract:
1. A method for controlling a nozzle position in an image forming apparatus comprising a nozzle plate provided with a plurality of nozzles and an optical detection sensor located adjacent to the nozzle plate, in which a nozzle position information is measured with reference to a datum position and varied in accordance with the nozzle plate moving during the printing operation of the image forming apparatus, such that the nozzle position information is calculated by adding a first positional information of the datum position obtained using an effective detection area with a second positional information which is measured in a real-time basis during movement of the nozzle plate, and the position information of the effective detection area being defined to be a subject area to the detection and from which an amount of reflected light is measured at a light receiving part of the optical detection sensor, the method further comprising the steps of: a) printing a predetermined test pattern on a print medium; b) measuring a distance from the effective detection area at the time of starting the printing of the test pattern to the test pattern along a first coordinate axial direction; c) measuring a distance from the effective detection area at the time of starting the printing of the test pattern to the test pattern along a second coordinate axial direction; d) calculating positional information on an orthogonal coordinate system consisting of the first and second coordinate axial directions by combining the distances measured in steps b) and c); and e) recording the positional information calculated in step d) as the first positional information.