Patent ID: 7675534
Filing Date: 2010-03-09
Classification: B41J

Abstract:
1. A thermal printer comprising: a first print head operable to record a first donor image and a third donor image forming a part of a superimposed image on a receiver medium as the receiver medium passes through a printing nip between the first print head and a first platen; a second print head operable to record a second donor image and a fourth donor image forming a part of the superimposed image on a receiver medium as the receiver medium passes through a printing nip between the second print head and a second platen; a receiver medium transport system having a loading portion urging receiver medium from a supply to a printing path leading the first receiver medium past the first print head and second print head so that the first print head and second print head can transfer donor material to form the first donor image and second donor image of the superimposed image; a post printing system having a return path that guides a leading edge of the receiver medium to return to the printing path or to an exit path, and a movable return path diverter operated by a controllable return path actuator, said return path actuator being operable to move the return path diverter so that a leading edge of the receiver medium can be caused to enter a selected one of the return path and the exit path; and a controller adapted to integrate the operation of the first thermal print head, the second thermal print head and the receiver medium transport system to cause the receiver medium transport system to urge a first receiver medium from the supply to the printing path and along the printing path so that the first donor image and the second donor image can be recorded thereon, said controller then causing the return path actuator to position the return path diverter so that the leading edge of the receiver medium is returned to the printing path so that the third donor image and the fourth donor image can be recorded to form a superimposed image, wherein said controller is further adapted to urge a second receiver medium to the printing path in a manner that allows the leading edge of the second receiver medium to enter the first printing nip before printing of the fourth image plane on the first receiver medium is complete so that the first print head can begin recording a first donor image for a second superimposed image on the second receiver medium before printing of the first superimposed image has completed.