Drop firing control in multicolor ink jet printheads
View Patent ↗A print engine/controller suited to use with a drop on demand print head. The print engine/controller works with compressed page data having both JPEG contone image layers and a bi-level image plane compressed using a Group 4 facsimile protocol. It receives compressed image plane's and effects expansion and printing in a pipeline fashion. It consists of a high speed serial interface 27 (such as a standard IEEE 1394 interface), a standard JPEG decoder 28 , a standard Group 4 Fax decoder, a halftoner/compositor unit 29 , a tag encoder 30 by which to place infrared tags into a printed page, a line loader/formatter unit 31 feeding an interface 32 to the print head 33 . The decoders 28,88 and encoder 30 are buffered to the halftoner/compositor 29.
1. A printer comprising:
an inkjet printhead;
a print engine/controller comprising:
(i) a memory buffer configured to receive compressed page data supplied to the printer;
(ii) a contone image decoder to decode any compressed continuous tone image planes in the received compressed page data;
(iii) a bi-level decoder to decode any compressed bi-level image planes in the received compressed page data;
(iv) a half-toner/compositor to dither any continuous tone image planes and composite bi-level image plane data with any output plane; and
(v) a printhead driver to output the composite to the printhead;
wherein the print engine/controller is configured to enable a current page to be read from the memory buffer whilst a following page is being stored in the buffer.
2. A print engine/controller as claimed in claim 1 wherein the interface is a high-speed serial interface.
3. A print engine/controller as claimed in claim 1 wherein the contone image decoder is a JPEG decoder.
4. A print engine/controller as claimed in claim 1 wherein the contone image decoder outputs the separate color planes of the decoded image to separate buffers in a front end to the halftoner/compositor.
5. A print engine/controller as claimed in claim 1 wherein page data in each contone image plane is scaled in the halftoner/compositor.
6. A print engine/controller as claimed in claim 1 wherein the bi-level decoder is a Group 4 facsimile decoder.
7. A print engine/controller as claimed in claim 1 wherein the bi-level decoder decodes any compressed bi-level image plane in the received compressed image plane to respective buffers in a front end to the halftoner/compositor.
8. A print engine/controller as claimed in claim 1 wherein the page data in the bi-level image plane is scaled in the halftoner/compositor.
9. A print engine/controller as claimed in claim 1 further including an infrared tag encoder to produce an infrared image plane to place infrared ink printed tags into a printed page.
10. A printer comprising:
an ink drop printhead;
a print engine/controller to drive the printhead, the print engine/controller comprising:
(i) a memory buffer configured to receive compressed page data supplied to the printer;
(ii) a contone image decoder to decode any compressed continuous tone image planes in the received compressed page data;
(iii) a bi-level decoder to decode any compressed bi-level image plane in the received compressed page data; and
(iv) a halftone/compositor including a dot merger unit controlled by a color mask to effect integration of the image planes with what inks are provided in the printhead;
wherein the print engine/controller is configured to enable a current page to be read from the memory buffer whilst a following page is being stored in the buffer.
11. A printer comprising:
an ink drop printhead;
a print engine/controller to drive the printhead, the print engine/controller comprising:
(i) a memory buffer configured to receive compressed page data supplied to the printer
(ii) a contone image decoder to decode any compressed continuous tone image planes in the received compressed page data;
(iii) a bi-level decoder to decode any compressed bi-level image plane in the received compressed page data; and
(iv) a halftone/compositor including a margin unit to apply margin data to the respective image planes during the composite process;
wherein the print engine/controller is configured to enable a current page to be read from the memory buffer whilst a following page is being stored in the memory buffer.