Method and apparatus for an external media buffer

A media transport mechanism comprising:

• a. a drive roller and an idler roller paired together forming a nip;
• b. roller drive means for rotating the drive roller;
• c. first sensor means for sensing a leading end of media approaching the nip of the drive roller and the idler roller and in response thereto signaling said roller drive means to begin rotation of the drive roller;
• d. transport means for transporting the drive roller and the idler roller back and forth between a media pick-up position and a media delivery position;
• e. movable media guide means for guiding media into the nip of the drive roller and idler roller while said movable guide means is in a first position, and for allowing a slack loop to form in the media as the transport means begins to transport the drive roller and idler roller away from the media pick-up position thereby preventing buckling of the media while said movable guide means is in a second position;
• and
• e. second sensor means for sensing the leading end of media exiting the nip and in response thereto signaling the roller drive means to stop rotation of said drive roller, signaling the transport means to transport the drive roller and idler roller from the media pick-up position to the media delivery position, and signaling the movable media guide means to move into the second position.

A method for buffering a sheet of media having a leading end and a trailing end, between a first media handling station and a second media handling station, comprising the steps of:

• a. gripping the leading end of the sheet as the sheet continues advancing at a first speed from the first media handling station;
• b. transporting the leading end of the sheet at a second speed from the first media handling station to the second media handling station as the sheet continues advancing at a first speed from the first media handling station;
• c. forming a slack loop in the sheet of media due to the second speed being slower than the first speed during transportation of the leading end of the sheet to the second media handling station until the trailing end of the sheet advances out from the first media handling station;
• and
• d. releasing the leading end of the sheet and transporting the leading end to the second media handling station.

A method for buffering a media sheet between a first media handling station and a second media handling station by a pair of media transport rollers carried by a linear transport device, comprising the steps of:

• a. positioning the rollers at the first media handling station;
• b. feeding the media sheet continuously toward the rollers at a first speed from the first media handling station;
• c. rotating the rollers an amount sufficient to grip and hold a leading end of the media sheet stationary relative to the rollers;
• d. transporting the rollers and the leading end at a second speed slower than the first speed, away from the first media handling station;
• e. forming a slack loop of media between the rollers and the first media handling station until a trailing end of the media sheet is fed toward the rollers from the first media handling station;
• f. positioning the rollers at the second media handling station;
• g. rotating the rollers to feed the media sheet from the leading end to the trailing end into the second media handling station;
• and
• h. transporting the rollers from the second media handling station to the first media handling station.