Multiple marker inkjet printing for increased print speed

A method for printing ink drops in an inkjet printing system where image pixels of a given color can be printed by two or more printheads each including a nozzle array for ejecting droplets of said given color and mounted in a scanning printhead carriage which moves over a print media in successive passes and swaths, and wherein a first printhead nozzle array has one or more failed nozzles, the method comprising:

• receiving print data from a print job source;
• producing from the print data a first plane for said given color;
• replicating the first plane to produce a second plane for said given color;
• using said first plane to produce a first set of printhead data signals for producing droplets, and said second plane to produce a second set of printhead data signals for producing droplets, wherein pixel data to be printed using said one or more of said failed nozzles is redirected to be printed by a corresponding equivalent one or more nozzles on a second printhead nozzle array;
• applying said first and second sets of printhead data signals to first and second printheads each for emitting droplets of said given color, thereby providing nozzle substitution for said one or more failed nozzles.

A method for printing ink drops in a color inkjet printing system using yellow, cyan, magenta and black inks, and wherein black image pixels are printed by two or more printheads ejecting droplets of black ink, comprising:

• providing print data defining a print job, said print data in respective yellow, cyan and magenta data planes and a first black data plane;
• replicating the first black data plane to produce a second black data plane;
• using said first black plane to produce a first set of black printhead data signals for producing black ink droplets, and said second black plane to produce a second set of black printhead data signals for producing black ink droplets;
• using said yellow, cyan and magenta data planes to respectively produce a set of yellow printhead data signals, a set of cyan printhead data signals and a set of magenta data signals;
• applying said first and second sets of black printhead data signals to first and second black ink printheads, said set of yellow printhead data signals to a yellow ink printhead, said set of cyan printhead data signals to a cyan ink printhead and said set of magenta printhead data signals to a magenta ink printhead.

A method for printing ink drops in an inkjet printing system where image pixels of a given color can be printed by two or more printheads ejecting droplets of said given color and mounted in a scanning printhead carriage, the method comprising:

• receiving print data from a print job source;
• producing from the print data a first plane for said given color comprising contone values;
• processing the contone values to produce two or more different planes of respective half-tone values corresponding to a number of ink droplets to be printed to represent respective pixels by said two or more printheads;
• using said two or more planes of half-tone values to produce corresponding two or more sets of printhead data signals for producing droplets;
• applying said two or more sets of printhead data signals to said two or more printheads each for emitting droplets of said given color.

A method for printing ink droplets in a color inkjet printing system using yellow, cyan and magenta inks and a secondary color ink, yellow, cyan and magenta inks being primary colors of ink, and wherein image pixels of the secondary color are printed by two or more printheads ejecting droplets of said secondary color ink, comprising:

• providing respective yellow, cyan and magenta and said secondary color data planes, said respective planes defining a colored image to be printed by the printing system;
• processing the secondary color data plane to determine first and second pseudo primary color planes whose addition results in the secondary color plane;
• using said first pseudo primary plane to produce a first set of secondary color printhead data signals for producing secondary color ink droplets, and said second pseudo primary plane to produce a second set of black printhead data signals for producing secondary color ink droplets;
• using said yellow, cyan and magenta data planes to respectively produce a set of yellow printhead data signals, a set of cyan printhead data signals and a set of magenta data signals;
• applying said first and second sets of secondary color printhead data signals to first and second secondary ink printheads, said set of yellow printhead data signals to a yellow ink printhead, said set of cyan printhead data signals to a cyan ink printhead and said set of magenta printhead data signals to a magenta ink printhead.

A method for printing ink droplets in a color inkjet printing system using yellow, cyan and magenta inks and a secondary color ink, yellow, cyan and magenta inks being primary colors of ink, and wherein image pixels of the secondary color are printed by two or more printheads ejecting droplets of said secondary color ink, comprising:

• providing respective yellow, cyan and magenta and said secondary color data planes, said respective planes defining respective contone values for pixels of a color image to be printed by the printing system;
• converting the contone values of the respective yellow, cyan and magenta color data planes into respective values corresponding to a number of ink droplets to be printed to represent respective pixels;
• converting the contone values of the secondary color plane into respective first and second pseudo primary color plane values corresponding to respective numbers of ink droplets of the respective first and second primary colors whose addition results in the secondary color plane;
• using said first pseudo primary plane values to produce a first set of secondary color printhead data signals for producing secondary color ink droplets, and said second pseudo primary plane values to produce a second set of secondary color printhead data signals for producing secondary color ink droplets;
• using said yellow, cyan and magenta data planes values to respectively produce a set of yellow printhead data signals, a set of cyan printhead data signals and a set of magenta data signals;
• applying said first and second sets of secondary color printhead data signals to first and second secondary ink printheads, said set of yellow printhead data signals to a yellow ink printhead, said set of cyan printhead data signals to a cyan ink printhead and said set of magenta printhead data signals to a magenta ink printhead.

A method for printing ink drops in an inkjet printing system where image pixels of a given color can be printed by two or more printheads ejecting droplets of said given color and mounted in a scanning printhead carriage, the method comprising:

• receiving print data from a print job source;
• producing from the print data a first plane for said given color comprising contone values;
• processing the contone values by an n-bit half-toning algorithm to produce respective half-tone values corresponding to a number of ink droplets to be printed to represent respective pixels, wherein n is an integer larger than 1, so that the half-tone values can represent multiple dots per pixel;
• using said half-tone values to produce multiple levels of printhead data signals for producing said dots;
• dividing said multiple levels of printhead data signals between the two or more printheads;
• applying said divided levels of printhead data signals to said two or more printheads each for emitting droplets of said given color.