Inkjet printing: mask-rotation-only at page extremes; multipass modes for quality and throughput on plastic media

A method of printing desired images on a low-liquid-absorption printing medium, by construction from individual marks formed in pixel column-and-row arrays by a scanning multiple-nozzle pen that operates in conjunction with a printing-medium advance mechanism;

• said method comprising the steps of:
• scanning the pen repeatedly along a pen-scanning axis across the medium, to place marks on the medium within a swath of pixel rows that is exposed to the multiple nozzles of the pen, each nozzle corresponding to one pixel row;
• periodically advancing the printing medium relative to the pen, along a printing-medium-advance axis that is substantially orthogonal to the pen-scanning axis, to bring a fresh portion of the medium within the swath that is exposed to the pen;
• and
• in each scanning of the head across the medium, firing at most one-sixth of the nozzles in each pixel-position column.

A method of printing a desired image, which has two ends, on a printing medium by construction from individual marks formed in pixel column-and-row arrays by a scanning multiple-nozzle pen that operates in conjunction with a printing-medium advance mechanism;

• said printing medium being held taut beneath the pen except while printing near top and bottom edges of the printing medium, when it is constrained from only one direction;
• said method comprising the steps of:
• scanning the pen repeatedly along a pen-scanning axis across the medium, to place marks on the medium within a swath of pixel rows that is exposed to the multiple nozzles of the pen, each nozzle corresponding to one pixel row;
• when the pen is not substantially at either end of the desired image, and while the medium is held taut, periodically advancing the printing medium relative to the pen, along a printing-medium-advance axis that is substantially orthogonal to the pen-scanning axis, to bring a fresh portion of the medium within the swath that is exposed to the pen;
• whereby the pen moves stepwise from one end of the image to the other;
• and
• when the pen is substantially at either end of the desired image, at least if the medium is constrained from only one direction and at least until completion of full inking for the swath of pixel rows that is exposed to the nozzles of the pen, holding the printing medium substantially stationary relative to the pen while performing a plurality of said scanning steps;
• and wherein:
• the periodically-advancing step comprises advancing the printing medium between substantially every pair of scans of the pen.

A method of printing a desired image, which has two ends, on a printing medium by construction from individual marks formed in pixel column-and-row arrays by a scanning multiple-nozzle pen that operates in conjunction with a printing-medium advance mechanism;

• said printing medium being held taut beneath the pen except while printing near top and bottom edges of the printing medium, when it is constrained from only one direction;
• said method comprising the steps of;
• scanning the pen repeatedly along a pen-scanning axis across the medium, to place marks on the medium within a swath of pixel rows that is exposed to the multiple nozzles of the pen, each nozzle corresponding to one pixel row;
• when the pen is not substantially at either end of the desired image, and while the medium is held taut, periodically advancing the printing medium relative to the pen, along a printing-medium-advance axis that is substantially orthogonal to the pen-scanning axis, to bring a fresh portion of the medium within the swath that is exposed to the pen;
• whereby the pen moves stepwise from one end of the image to the other;
• and
• when the pen is substantially at either end of the desired image, at least if the medium is constrained from only one direction and at least until completion of full inking for the swath of pixel rows that is exposed to the nozzles of the pen, holding the printing medium substantially stationary relative to the pen while performing a plurality of said scanning steps;
• and wherein:
• during the holding-stationary step, said scanning steps comprise employing a sequence of print masks in rotation to progressively provide full inking for the swath of pixel rows that is exposed to the nozzles of the pen;
• and
• said sequence of masks is such as to compensate for absence of printing-medium advance.