Reflex printing with process direction stitch error correction
AssigneeXerox Corporation
InventorsGregg Guarino, Daniel Costanza, Martin Hoover, James Calamita, Abu Islam
Life of this patent
Estimating the term…
Abstract
A reflex printing device having multiple print heads mounted at different locations around the circumference of the drum at different “angles” and an encoder disk mounted on the drum to allow for detection of the drum position as a function of time. An image defect due to a misalignment in the print process direction of the output from the multiple print heads is corrected by detection of an encoder position error function subtracted from itself shifted by the angle between the print heads.
Claims20
An image formation apparatus, comprising:
- a rotatable drum;
- at least two print heads disposed over a surface of the drum at different angular positions that eject ink onto the surface of the drum;
- an encoder disk connected to an axial end of the drum that rotates with the drum;
- an encoder sensor positioned to detect a position of the encoder disk as the encoder disk rotates with the drum;
- a ink sensor positioned over the surface of the drum that detects a relative position of ink ejected on to the surface of the drum from the at least two print heads;
- and
- an encoder corrector operably connected to the at least two print heads, the encoder disk, the encoder sensor and the ink sensor, wherein the encoder corrector receives a signal from the ink sensor and the encoder sensor and reduces stitch error by controlling a timing of ink ejection from the at least two print heads based on the received signals.
A method of reducing stitch error in a an image formation device, comprising:
- detecting placement of marks on a surface of a rotating drum;
- detecting a relative position of the drum when the marks are placed on the surface of the drum;
- storing data representing the detected placement of the marks and the detected relative position of the drum in a memory;
- calculating an error of ink placement on the surface of the drum based on the stored data;
- and
- reducing the error by controlling ejection of ink from at least two print heads onto the surface of the drum based on the calculated error.
An image formation apparatus, comprising:
- a controller operably connected to the at least two print heads, an encoder disk, an encoder sensor and an ink placement sensor, that controls:
- detecting placement of marks on a surface of a rotating drum;
- detecting a relative position of the drum when the marks are placed on the surface of the drum;
- storing data representing the detected placement of the marks and the detected relative position of the drum in a memory;
- calculating an error of ink placement on the surface of the drum based on the stored data;
- and
- reducing the error by controlling ejection of ink from at least two print heads onto the surface of the drum based on the calculated error.
Dependencies are inferred from the claim text.