Patent ID: 8991962
Filing Date: 2015-03-31
Classification: B41J

Abstract:
1. A method of printing a spit pattern for an inkjet printer, the inkjet printer comprising a print head having a plurality of nozzles, wherein a receiving material is moved relatively to the print head and droplets of marking material are ejected from the nozzles onto the receiving material in order to form the spit pattern of dots of marking material on the receiving material, wherein the method comprises the steps of: selecting a dot distance between the dots of the spit pattern to be ejected by a nozzle, the dot distance being expressed in a number of dots; selecting at least a sub-matrix of a dither matrix of entries arranged in rows and columns, each entry comprising a positive natural number, wherein the number of rows of the sub-matrix is less than or equal to the numeric value of the dot distance; determining a threshold value based on the selected dot distance and on the dither matrix; constructing a bi-level bitmap of the same size as the sub-matrix, each entry of the bi-level bitmap having a row number and a column number and having a value of zero or one dependent on the threshold value and the value of the corresponding entry in the sub-matrix; splitting each column of the bi-level bitmap, which has more than one entry having a value of one, into a number of columns such that each column of the number of columns comprises exactly one entry having a value of one; removing each column of the bi-level bitmap, which has no entry having a value of one; extracting the row number and column number of each entry of the bi-level bitmap having a value of one; adapting the row number of each extracted entry in accordance with the dot distance; and printing the spit pattern by ejecting droplets of marking material forming the dots on locations on the receiving material according to the column number and adapted row number of each extracted entry.