US 6,142,605 A · Bidirectional color printing using multipass printmodes with at least partially swath-aligned inkjet printheads

Abstract

The method enables swath-type bidirectional printing without hue shift, using plural scanning multiple-inkjet printheads (holding inks of different colors respectively) and printing-medium advance orthogonal to the scan axis. Inking is calculated and implemented for each position in the grid independently. Images appear as a pixel grid of columns and rows both spaced--i.e. in both the scan and media-advance directions--more finely than 300 dpi. In one aspect of the invention, both these resolutions are the same, and equal to the nozzle spacing. At least some of the nozzles are overlapping and respectively aligned along the advance axis, to be capable of printing on adjacent rows during a single pass. In another aspect of the invention, the nozzle arrays only partially overlap, so as to use significantly fewer than the total number of nozzles in each array. As to this second aspect of the invention, in each nozzle array the method uses a number of nozzles that is fewer than the total nozzle complement by a certain number that is preferably at least fifteen, more preferably thirty, and ideally roughly sixty nozzles.

Claims20

Dependent claims

A method for swath-type ink printing without hue shift of a color printout on a printing medium with a pixel grid of rows separated by a given first true resolution in a media advance direction;

said method comprising the steps of:
installing a plurality of inkjet printheads in a scanning carriage which moves along a scanning axis in a forward printing direction and in a rearward printing direction across the printing medium with a pixel grid of columns separated by a given second resolution in said scanning axis, each of said printheads having a different color of ink, and each of said printheads having multiple nozzles with a nozzle resolution in the media advance direction greater than 300 dpi, said nozzle resolution being the same as the given first true resolution of the rows;
positioning the inkjet printheads in the scanning carriage such that at least some of the multiple nozzles of the inkjet printheads are overlapping and respectively aligned in order to be capable of printing on adjacent rows during a single pass of the carriage along the scanning axis;
calculating inking for each position in the grid independently;
and
performing bidirectional color printing in both the forward printing direction and the rearward printing direction across the printing medium, including independently implementing the inking for each position in the grid.

3 more elements

Dependencies are inferred from the claim text.

Bidirectional color printing using multipass printmodes with at least partially swath-aligned inkjet printheads

Life of this patent

Bidirectional color printing using multipass printmodes with at least partially swath-aligned inkjet printheads

Life of this patent

Abstract

Claims20