METHOD AND APPARATUS FOR PREVENTING EJECTION FAILURES CAUSED BY MEDIA DEFORMATIONS

The present invention relates to a method of controlling an inkjet printing device comprising one or more print heads each print head comprising a plurality of nozzles, a sensor for detecting printing media deformations located such that printing media travels under said sensor before travelling under the one or more print heads, and a scanner located such that printing media travels under said scanner after travelling under the one or more print heads. The method comprises a first step of detecting media deformations using the sensor. Subseqeuntly, if deformations are detected in the printing media, printing is inhibited. If printing has been inhibited, the method of the present invention continues with a step of sensing a pressure wave in the liquid in the plurality of ducts of the plurality of nozzles of one or more of the print heads, while the printing media travels under the one or more print heads resulting in a plurality of sensed pressure waves. The next step of the method of the preent invention comprises inferring from the plurality of sensed pressure waves which nozzles of the plurality of nozzles enter in contact with the deformed printing media while the printing media travels under the one or more print heads. Finally, the parts of the image printed by the nozzles that have been previously determined to have entered in contact with the deformed printing media are scanned after a subsequent printing of the inhibited printing job.