Maintenance on a hand-held printer

A method of performing maintenance on a hand-held printer, said hand-held printer including a printhead with a plurality of nozzles and adapted to print a user-desired output image as said printer is manually moved across a surface, comprising:

• generating a first set of print instructions that cause said hand-held printer to print said user-desired output image, said print instructions identifying a firing order for said plurality of nozzles;
• analyzing, while printing said user-desired output image, said firing order for at least some of said plurality of nozzles to determine when one or more of said plurality of nozzles are likely to require a maintenance action;
• and
• modifying said first set of print instructions such that said hand-held printer will perform at least one maintenance action as said hand-held printer is manually moved across said surface while printing said user-desired output image.

A method of performing maintenance on a printer that is manually moved across a surface to print an image, said method comprising:

• generating print instructions for said image that dictate when and where each of a plurality of nozzles will fire to print said image;
• determining which of said plurality of nozzles requires a maintenance action as said printer prints said image;
• and
• including in said print instructions at least one instruction related to a performance of said maintenance action, wherein said step of determining which of said plurality of nozzles requires a maintenance action comprises assuming a minimal user printing speed to determine a time period between firings of each nozzle.

A method of performing maintenance on a printer that is manually moved across a surface to print an image, said method comprising:

• generating print instructions for said image that dictate when and where each of a plurality of nozzles will fire to print said image;
• determining, while printing said image, which of said plurality of nozzles requires a maintenance action;
• and
• including in said print instructions at least one instruction related to a performance of said maintenance action, said at least one instruction comprising including a print instruction that causes a nozzle to fire in a high density region of said image at least once to clear said nozzle.

A method of performing maintenance on a printer that is manually moved across a surface to print an image, said method comprising:

• generating print instructions for said image that dictate when and where each of a plurality of nozzles will fire to print said image;
• determining, while printing said image, which of said plurality of nozzles requires a maintenance action by assuming a minimal user printing speed to determine a time period between firings of each nozzle;
• and
• including in said print instructions at least one instruction related to a performance of said maintenance action.

A method of performing maintenance on a printer that is manually moved across a surface to print an image, said method comprising:

• generating print instructions for said image that dictate when and where each of a plurality of nozzles will fire to print said image;
• determining, while printing said image, which of said plurality of nozzles requires a maintenance action comprising using, for each of the plurality of nozzles, the following:
• if (NozzleIdleTime>15)
• {
• P=k1(pdnsity)+k2(pothers)+k3(ptemp)+k4(ptime);
• if (P>0.8)
• {
• FireNozzle ( );
• }
• }
• where P is a probability to fire a particular nozzle, pdnsity is a density of a swath firing around a dot location, pothers is a number of other maintenance dots at that time, ptime is an idle time of the particular nozzle, ptemp is a parameter associated with maintaining a predetermined target printhead temperature, and k1, k2, k3 and k4 are weightings on said pdnsity, pothers, ptemp, and ptime values;
• and,
• including in said print instructions at least one instruction related to a performance of said maintenance action.