Sheet recording apparatus with dual nip transport

An apparatus for recording an image onto a sheet medium, comprising:

• a) an entrance drive roller paired with a corresponding entrance pressure roller to form an entrance nip for transporting the sheet medium into an image recording section;
• b) the image recording section comprising a write head for recording onto a portion of the sheet medium being transported between the entrance nip and an exit nip;
• c) the exit nip formed by a drive roller paired with a corresponding exit pressure roller, for transporting the sheet medium out from the image recording section;
• d) a motor for rotating the exit drive roller;
• e) a coupling apparatus for coupling rotary motion between the exit drive roller and the entrance drive roller, the coupling apparatus comprising:
• i) a coupling roller elongated in the width dimension of the sheet medium;
• ii) a loading mechanism providing a loading force to nest the coupling roller into continuous rotational contact against the entrance and exit drive rollers;
• whereby rotation is transferred between the exit drive roller and the entrance drive roller by the coupling roller;
• and
• wherein the coupling apparatus further comprises a counter roller coupling the exit drive roller with the entrance drive roller.

An apparatus for recording an image onto a sheet medium, comprising:

• a) an entrance drive roller paired with a corresponding entrance pressure roller to form an entrance nip for transporting the sheet medium into an image recording section;
• b) the image recording section comprising a write head for recording onto a portion of the sheet medium being transported between the entrance nip and an exit nip;
• c) the exit nip formed by a drive roller paired with a corresponding exit pressure roller, for transporting the sheet medium out from the image recording section;
• d) a coupling apparatus for coupling rotary motion to the exit drive roller and the entrance drive roller, the coupling apparatus comprising:
• i) a coupling roller elongated in the width dimension of the sheet medium;
• ii) a motor for driving the coupling roller;
• iii) a loading mechanism providing a loading force to nest the coupling roller into continuous rotational contact against the entrance and exit drive rollers;
• and
• wherein the coupling apparatus further comprises a counter roller coupling the exit drive roller with the entrance drive roller.

An apparatus for recording an image onto a sheet medium, comprising:

• a) a first drive roller paired with a corresponding first pressure roller to form a first nip for transporting the sheet medium;
• b) a second drive roller paired with a corresponding second pressure roller to form a second nip for transporting the sheet medium;
• c) an image recording section comprising a write head for recording onto a portion of the sheet medium being transported between the first and second nips;
• d) a motor for rotating the first drive roller;
• e) a coupling apparatus for coupling rotary motion between the first and second drive rollers, the coupling apparatus comprising:
• i) a coupling roller elongated in the width dimension of the sheet medium;
• ii) a loading mechanism providing a loading force to nest the coupling roller into continuous rotational contact against the first and second drive rollers;
• whereby rotation is transferred between the first and second drive rollers by the coupling roller;
• and
• wherein the coupling apparatus further comprises a counter roller coupling the exit drive roller with the entrance drive roller.

A method for image recording onto a sheet medium comprising:

• a) transporting the sheet medium into an image recording section through an entrance nip formed by pairing an entrance drive roller with a corresponding entrance pressure roller;
• b) recording the image onto a portion of the sheet medium being transported between the entrance nip and an exit nip;
• c) transporting the sheet medium out from the image recording section through the exit nip formed by pairing a drive roller with a corresponding exit pressure roller;
• d) rotating either the entrance drive roller or the exit drive roller from a motor;
• e) coupling rotary motion between the exit drive roller and the entrance drive roller by nesting a coupling roller into continuous rotational contact against the entrance and exit drive rollers, the coupling roller elongated in the width dimension of the sheet medium;
• transferring rotation between the exit drive roller and the entrance drive roller by the coupling roller thereby;
• and
• nesting a counter roller into contact with a portion of the surface of the entrance drive roller and a portion of the surface of the exit drive roller, providing additional coupling stiffness thereby.