A method of operating an ink jet card printer having a transport belt, a print unit including an inkjet print head, a sensor and a gantry supporting the ink jet print head and the sensor for movement relative to the transport belt, the method comprising: loading a card onto the transport belt including engaging the card with an exposed surface of the transport belt and driving the card along a processing axis using the exposed surface of the transport belt; moving the sensor and the ink jet print head relative to the card using the gantry; detecting a current position of the card relative to the processing axis using the sensor; printing an image to the card using the ink jet print head when the detected current position of the card indicates that the card is supported on the transport belt in a print position; and interrupting printing an image to the card using the ink jet print head when the detected current position of the card indicates that the card is not in the print position, wherein interrupting printing an image to the card comprises: discharging the card from the transport belt including driving the card along the processing axis using the transport belt; reloading the card onto the transport belt including driving the card along the processing axis using the transport belt; detecting a new current position of the card relative to the processing axis using the sensor; and printing an image to the card using the ink j et print head when the detected new current position of the card indicates that the card is in the print position. loading a card onto the transport belt including engaging the card with an exposed surface of the transport belt and driving the card along a processing axis using the exposed surface of the transport belt; moving the sensor and the ink jet print head relative to the card using the gantry; detecting a current position of the card relative to the processing axis using the sensor; printing an image to the card using the ink jet print head when the detected current position of the card indicates that the card is supported on the transport belt in a print position; and interrupting printing an image to the card using the ink jet print head when the detected current position of the card indicates that the card is not in the print position, wherein interrupting printing an image to the card comprises: discharging the card from the transport belt including driving the card along the processing axis using the transport belt; reloading the card onto the transport belt including driving the card along the processing axis using the transport belt; detecting a new current position of the card relative to the processing axis using the sensor; and printing an image to the card using the ink j et print head when the detected new current position of the card indicates that the card is in the print position. discharging the card from the transport belt including driving the card along the processing axis using the transport belt; reloading the card onto the transport belt including driving the card along the processing axis using the transport belt; detecting a new current position of the card relative to the processing axis using the sensor; and printing an image to the card using the ink j et print head when the detected new current position of the card indicates that the card is in the print position.