Media advance system for swath printers

For a media advance system for a swath printer, comprising a swath-type printing head, with N spaced printing devices means for mounting said printing head for movement along a first predetermined axis, means for advancing the print media along a second predetermined axis substantially orthogonal to the first axis, and a line sensor mounted adjacent a first one of said printing devices and carried by said mounting means, said line sensor comprising means for imaging lines drawn in the media margin, a method for controlling said printing head and said media advancing means for accurately advancing said media upon the printing of a swath, comprising a sequence of the following steps:

• (i) printing an initial swath with said media positioned appropriately for the beginning of a new plot or page, and printing two marginal lines in the direction of the swath with the first printing device and with the Nth printing device;
• (ii) centering in the swath direction the line sensor over said margin line drawn by said first print device without moving the media from the position at which the first swath was printed, and storing the sensor output signal value as a reference signal indicative of the mounting error between said sensor and the first printing device;
• (iii) advancing the media to a position wherein the sensor provides an output signal equal to said reference value, indicating that the sensor is centered over the marginal line drawn by said Nth printing device;
• (iv) advancing the media a predetermined amount equal to one printing device pitch;
• (v) printing the next swath and a margin line printed by said Nth printing device;
• and
• (vi) repeating steps (iii), (vi) and (v) until the plot or page is complete.

For media advance system for a swath printer, comprising a swath-type printing head with N spaced printing devices, means for mounting said printing head for movement along a first predetermined axis, means for advancing the print media along a second predetermined axis substantially orthogonal to the first axis, and a line sensor mounted adjacent a first one of said printing devices and carried by said mounting means, said line sensor comprising means for imaging lines drawn in the media margin, a method for controlling said printing head and said media advancing means for accurately advancing said media upon the printing of a swath, comprising a sequence of the following steps:

• (i) printing an initial swath with said media positioned appropriately for the beginning of a new plot or page, and printing two marginal lines in the direction of the swath with the first printing device and with the Nth printing device;
• (ii) positioning in the swath direction the line sensor over said margin line drawn by said first print device without moving the media and storing the sensor output signal value as a reference signal indicative of the mounting error between said sensor and the first printing device;
• (iii) advancing the media to a position wherein the sensor provides an output signal equal to said reference value, indicating that the sensor is centered over a marginal line drawn by said Nth printing device;
• (iv) printing the next swath and a margin line printed by said Nth printing device, without using the first printing device;
• and
• (v) repeating steps (iii) and (iv) until the plot or page is completed.

A media advance system for a swath printer, comprising:

• a swath-type printing head, said head comprising N spaced printing devices;
• means for mounting said printing head for movement along a first predetermined axis;
• means for advancing the print media along a second predetermined axis substantially orthogonal to the first axis;
• a line sensor mounted adjacent a first one of said printing devices and carried by said mounting means, said line sensor comprising means for imaging lines drawn in the media margin;
• system controller responsive to said line sensor for controlling said printing head and said media advancing means for accurately advancing said media upon the printing of a swath, said controller comprising, in combination with said print head, said mounting means and said media advancing means:
• (i) first means for printing an initial swath with said media positioned appropriately for the beginning of a new plot or page, and for printing two marginal lines in the direction of the swath with the first printing device and with the Nth printing device;
• (ii) means for positioning in the swath direction the line sensor over said margin line drawn by said first print device without moving the media from the position at which the first swath was printed, and storing the sensor output signal value as a reference signal indicative of the mounting error between said sensor and the first printing device;
• (iii) means for advancing the media to a position wherein the sensor provides an output signal equal to said reference value, indicating that the sensor is positioned over the marginal line drawn by said Nth printing device;
• and
• (v) second means for printing the next swath and a margin line printed by said Nth printing device without overlapping the previously printed swath.