Method of generating print data for inkjet printhead
A method of generating print data for an inkjet printhead having a plurality of ink planes. The method includes the steps of: receiving image data for a print job in a printer controller; retrieving keep-wet pattern data for each ink plane of the printhead, the retrieved keep-wet pattern data being determined using one or more input parameters; generating first print data for each ink plane in the printer controller based on the received image data; merging the first print data with the keep-wet pattern data to provide second print data for each ink plane; and sending the second print data from the printer controller to the printhead, thereby causing the printhead to print an image together with a keep-wet pattern. The keep-wet pattern is defined by a plurality of dots printed at a frequency sufficient to maintain hydration of each nozzle in the printhead.
1. A method of printing an image from a printer having a plurality of ink planes, each ink plane comprising one or more rows of nozzles supplied with the same ink, the method comprising the steps of:
printing the image; and
simultaneously printing a keep-wet pattern together with the image, wherein:
the keep-wet pattern comprises a pseudo-random pattern of dots printed at a frequency sufficient to ensure that each nozzle of the printhead is fired within a predetermined period of time which is less than a decap time of said nozzle; and
the keep-wet pattern for each ink plane is determined using one or more input parameters selected from the group consisting of:
a position of each ink plane in the printer;
a print speed of the print job;
a type of ink printed from each ink plane;
a type of print medium;
a length of the print job;
an ambient humidity;
an ambient temperature;
the image content;
optical interference between keep-wet patterns printed from each ink plane; and
a minimum print quality threshold.
2. The method of claim 1 , wherein at least one ink plane ejects a different keep-wet pattern than at least one other ink plane of the printer.
3. The method of claim 1 , wherein a printer controller retrieves keep-wet pattern data for the keep-wet pattern.
4. The method of claim 3 , wherein the printer controller comprises a memory storing a plurality of different keep-wet pattern data, and wherein the printer controller retrieves the keep-wet pattern data for a print job from the memory.
5. The method of claim 1 , wherein the keep-wet pattern data for each ink plane is determined using at least the following two parameters:
a position of each ink plane in the printer relative to the media feed direction; and
a type of ink printed from each ink plane.
6. The method of claim 1 , wherein the keep-wet pattern for each ink plane is determined by an algorithm, the algorithm weighting said one or more parameters.
7. The method of claim 6 , wherein printer firmware or a printer driver comprises the algorithm.
8. The method of claim 1 , wherein the pseudo-random pattern of dots defining the keep-wet patterns for different ink planes are not printed dot-on-dot.