Patent ID: 8702204

Claim:
Method of printing multi-colored images by applying colored ink dots to a print medium with an inkjet printer having a printing bed for displacing a print medium in a forward feed direction and with a print head carriage disposed above the printing bed for displacing at least one print head unit in a transverse feed direction, a print head unit with at least one print head being provided for every color to be printed and each print head having a nozzle row oriented in the forward feed direction of the print medium, the method comprising: generating control signals for the ink dots by a control unit from digital image data and activating nozzles of at least one nozzle row of the at least one print head unit; determining control signals for additional ink dots for a color not contained in the image data, wherein white ink is used for the additional ink dots; and in a printing mode for applying colored images to a reverse face of a transparent print medium, applying the colored ink dots first of all and then applying the additional ink dots to the entire area of the image, and after applying the additional ink dots, applying the colored ink dots, wherein by the control signals determined for the white ink dots another print head unit with nozzles for printing white color disposed in at least one nozzle row oriented in the forward feed direction of the print medium and of an effective row length is activated, and an at least first effective row length of a nozzle row for printing a first color within the at least one print head unit and the effective row length of the nozzle row for printing the white color at least partially overlap each other in the transverse feed direction, and wherein nozzles of the nozzle row for printing said first color as well as nozzles of the nozzle row for printing the white color are activated during a single transverse movement of the print head carriage, and of the nozzles of the nozzle row for printing the first color, only those nozzles lying outside of an overlap region between the effective row length of the nozzle row for printing the first color and a row length of the nozzle row for printing the white color are activated.