Controlling media curl in print-zone

An inkjet printing apparatus which moves print media along a media path, comprising:

• an inkjet printhead having a plurality of inkjet nozzles which eject ink onto a portion of said media located within a print-zone;
• means for supporting the media as the media passes along the media path through the print-zone;
• means, located upstream along the media path prior to the print-zone, for stabilizing the media relative to a first surface during printing onto at least a first portion of the media;
• and
• means, located along the media path extending before, even with and beyond the print-zone during printing to the media, for holding a side edge of the media to the supporting means within a printing margin of the media;
• wherein the support means comprises a recessed portion and a non-recessed portion, the media spanning along the non-recessed portion into the recessed portion, the holding means aligned within the recessed portion for holding the media side edge into the recessed portion.

An inkjet printing apparatus which moves print media along a media path, comprising:

• an inkjet printhead having a plurality of inkjet nozzles which eject ink onto a media portion located within a print-zone;
• a support which supports the media as the media passes along the media path through the print-zone;
• a roller located upstream along the media path prior to the print-zone, the roller stabilizing the media relative to a first surface during printing onto at least a first portion of the media;
• and
• a guide shim located downstream of the print-zone which captures a leading edge of the media as it exits the print-zone, the guide shim configured to reduce media curling.

A method of advancing print media along a media path through a print-zone of an inkjet printing apparatus, the method comprising:

• receiving a center portion of the media at a central length of a drive shaft;
• receiving a side edge of the media at a recess along the drive shaft, the drive shaft having a first radius along the central length and a second radius, less than the first radius, at the recess;
• biasing a side portion of the media into the recess with a first guide aligned with the first recess and spaced from a longitudinal axis of the drive shaft by a first distance which is less than the first radius;
• advancing the media through the print-zone;
• and
• ejecting ink onto the media when located within the print-zone.

A method of advancing print media along a media path through a print-zone of an inkjet printing apparatus, the method comprising:

• receiving a center portion of the media at a first pinch roller of a plurality of pinch rollers;
• receiving a side portion of the media at a second pinch roller of the plurality of pinch rollers, wherein the second pinch roller has a smaller diameter than the first pinch roller and has an axis which is closer to the print-zone than the first roller, the second pinch roller reduces lifting of the media in the print-zone;
• advancing the media through the print-zone;
• and
• ejecting ink onto a portion of the media when located within the print-zone.

A method for advancing print media along a media path through a print-zone of an inkjet printing apparatus, the method comprising the steps of:

• receiving said media at pinch rollers which stabilize the media along the media path relative to a first surface, the rollers located upstream along the media path prior to the print-zone;
• receiving a leading edge of the media under a guide shim located along a portion of the media path extending before, even with and beyond the print-zone;
• receiving a side portion of the media under the guide shim and within a recessed portion of a platen, the platen having a non-recessed portion and the recessed portion, the media spanning the non-recessed portion into the recessed portion, the guide shim aligned within the recessed portion for holding the media side edge into the recessed portion;
• and
• ejecting ink onto a portion of the media located within the print-zone.

A method for advancing print media along a media path through a print-zone of an inkjet printing apparatus, the apparatus including an inkjet printhead having a plurality of inkjet nozzles which eject ink, the print-zone located adjacent to the plurality of nozzles, the method comprising:

• receiving the media at a roller which stabilizes the media along the media path relative to a first surface, the roller located upstream along the media path prior to the print-zone;
• ejecting ink onto a portion of the media located within the print-zone;
• advancing the media through the print-zone;
• capturing a leading edge of the media, as the media exits the print-zone, with a guide shim located downstream of the print-zone;
• and
• reducing media curling during said advancing.

An inkjet printing apparatus which moves a media along a media path, the media having a leading edge with leading corners, the apparatus comprising:

• an inkjet printhead having a plurality of inkjet nozzles which eject ink onto a media portion located within a print-zone;
• a drive shaft located upstream of the printhead and incrementally rotated to advance the media, the drive shaft having a first radius over a central length and a second radius less than the first radius at a first recess and a second recess, each said recess being peripheral to the central length;
• a plurality of pinch rollers for stabilizing the media against the drive shaft, comprising at least one first pinch roller and at least two second pinch rollers, the second pinch rollers having a smaller diameter and located peripherally relative to the first pinch roller, the second pinch rollers having an axis which is closer to the print-zone than an axis of the at least one first roller, the second pinch rollers for reducing lifting of the media in the print-zone by pinching toward side edges of the media;
• a first guide aligned with the first recess and spaced from an axis of the drive shaft by a first distance which is less than the first radius;
• a second guide aligned with the second recess and spaced from the axis by a second distance less than the first radius;
• a platen support for receiving the media from the drive shaft, the support having a first clearance for receiving a central portion of the leading edge and a second clearance greater than the first clearance, for receiving the leading corners;
• a first shim located along the media path extending even with and beyond the print-zone during printing to the media, the first shim holding a side edge of the media to the platen support within a printing margin of the media;
• and
• a second shim located downstream of the print-zone which captures a leading edge of the media as it exits the print-zone, the second shim for reducing media curling;
• wherein the platen support has a recessed portion and a non-recessed portion, the media spanning along a non-recessed portion into the recessed portion, the first shim aligned within the recessed portion for holding the media side edge into the recessed portion,
• wherein a top surface of the first shim is at or below a top surface of the media, so that a printhead to first shim height differential is at least as great as a printhead to underlying media spacing.