Patent ID: 8733892
Filing Date: 2014-05-27
Classification: B41J

Abstract:
1. A method for depositing a substance onto a receiving medium for said substance, by ink-jet printing using a head which is movable relative to the medium in a transverse direction and in a longitudinal direction perpendicular to said transverse direction, said head including at least one set of multiple ejection nozzles which are longitudinally offset relative to each other and which are each adapted to eject amounts of the substance in the direction of the medium with a fixed distance between said nozzle and said medium, the method comprising: for each nozzle, measuring a longitudinal deviation between a point of impact on the medium of an amount of substance ejected by the nozzle, and a position in the longitudinal direction of said nozzle when said nozzle ejects said amount of substance; determining a set of target points distributed in the longitudinal direction on the medium, at which amounts of substance are to be deposited; for an initial longitudinal offset of the head relative to the medium, parallel to the longitudinal direction, selecting those of the nozzles which have respective offsets in the longitudinal direction relative to certain target points, substantially opposite the respective longitudinal deviations of said nozzles, such that the points of impact on the medium of the amounts of substance ejected by the selected nozzles coincide with the corresponding target points parallel to said longitudinal direction; repeating the selecting step for a number of iterations while varying each iteration the longitudinal offset of the head beyond said initial longitudinal offset, by an increment of said longitudinal offset of the head that is less than or equal to the distance between two neighboring target points; placing the head facing the medium at the initial longitudinal offset, and activating the selected nozzles in accordance with predetermined amounts of substance to be deposited on the medium at said target points; and repeating the placing and activating steps for each longitudinal offset of the head, wherein each iteration of placing the head includes moving the head parallel to the transverse direction, and the nozzles selected for the longitudinal offset of the head occurring during said iteration are activated during the transverse movement of the head according to predetermined amounts of substance to be deposited on the medium at transverse offset locations, the nozzles not selected for said longitudinal offset of the head not being activated during said transverse movement of the head.