Creating composite page images from compressed data

• US 20030193676A1
• Filed: 04/24/2003
• Published: 10/16/2003
• Est. Priority Date: 04/23/1999
• Status: Active Grant

• Current Assignee: Memjet Technology Ltd. (Memjet Limited)
• Original Assignee: Silverbrook Research Pty Limited
• Inventors: Lapstun, Paul
• Granted Patent: US 6,982,799 B2
• Time in Patent Office: Days
• US Class Current: 358/1.8
• CPC Class Codes: B41J 11/002 Curing or drying the ink on the copy materials, e.g. by heating or irradiating
• CPC Class Codes: B41J 11/00216 using infrared [IR] radiation or microwaves
• CPC Class Codes: B41J 2/0057 where an intermediate transfer member receives the ink before transferring it on the printing material
• CPC Class Codes: B41J 2/01 Ink jet
• CPC Class Codes: B41J 2/04508 aiming at correcting other parameters
• CPC Class Codes: B41J 2/0451 for detecting failure, e.g. clogging, malfunctioning actuator
• CPC Class Codes: B41J 2/04586 controlling heads of a type not covered by groups B41J2/04575 - B41J2/04585, or of an undefined type
• CPC Class Codes: B41J 2/155 for line printing
• CPC Class Codes: B41J 2/2139 Compensation for malfunctioning nozzles creating dot place or dot size errors generating single droplets or particles on demand by pressure, e.g. electromechanical transducers B41J2/045
• CPC Class Codes: B41J 2202/21 Line printing
• CPC Class Codes: B41J 3/60 for printing on both faces of the printing material
• CPC Class Codes: G06F 13/00 Interconnection of, or transfer of information or other signals between, memories, input/output devices or central processing units interface circuits for specific input/output devices G06F3/00 ; multiprogram control therefor G06F9/46; multiprocessor systems G06F15/16
• CPC Class Codes: G06F 15/00 Digital computers in general details G06F1/00 – G06F13/00; Data processing equipment in general
• CPC Class Codes: G06F 3/12 Digital output to print unit , e.g. line printer, chain printer
• CPC Class Codes: G06K 15/00 Arrangements for producing a permanent visual presentation of the output data , e.g. computer output printersprinting or plotting combined with another operation, e.g. with conveying, G06K17/00
• CPC Class Codes: H04N 1/393 Enlarging or reducing

Abstract

A printhead controller controls printing of a page by at least one printhead. The printhead controller, in use, receives data, in a compressed format relating to the page to be printed, the data including a page description comprising a bi-level black layer and a contone color layer. The printhead controller extracts from the compressed data relating to the bi-level black layer the contone color layer. Memory is provided for temporary storage of the expanded data. A dithering/compositing unit produces a ditherer page from the data temporally stored in the memory and feeds its out put to the printhead.

Claims

1. A printhead controller for controlling printing of a page by at least one printhead, the printhead controller, in use, receiving data, in a compressed format, relating to the page to be printed, the data including a page description comprising a bi-level black layer and a contone color layer, the printhead controller including:

a decoding unit that extracts first data relating to the bi-level black layer and second data relating to the contone color layer from the compressed data;

memory that temporarily stores the first and second data;

a ditherer/compositor unit operable to;

produce a dithered bi-level color layer based on the second data,

produce a bi-level black layer based on the first data and

composite the bi-level black layer on the color layer after dithering thereof to produce a page image.

2. The printhead controller of claim 1 including a printhead interface that controls at least one printhead connected to the interface and that feeds the page image to the at least one printhead.

3. The printhead controller of claim 1 wherein the decoding unit includes a first decoded that extracts the first data and a second decoder that extracts the second data.

4. The printhead controller of claim 3 wherein the first and second decoders are arranged in parallel;

5. The printhead controller of claim 3 in which the first decoder is a lossless bi-level decompression device for decompressing the bi-level black layer.

6. The printhead controller of claim 3 in which the second decoder is a high-quality lossy decompression device for decompressing the contone color layer.

7. The printhead controller of claim 1 wherein the memory includes a first memory device that stores the first data and a second, physically distinct, memory device that stores the second data.

10. The printhead controller of claim 1 that functions as a self-synchronizing pipeline.

11. A method of creating and printing a page image from data, in a compressed format, relating to a page to be printed, the data including a page description comprising a bi-level black layer and a contone color layer, includes the steps of:

extracting first data relating to the bi-level black layer from the compressed data;

extracting second data relating to the contone color layer from the compressed data;

storing the in first and second data in memory;

retrieving the first and second data from the memory;

creating a dithered bi-level color layer from the second data;

creating bi-level black layer from the first data

compositing the bi-level black layer on the dithered bi-level color layer to create a dithered/composited page image, and

printing the page image.

8. The printhead controller of claim 11, further including a third memory device that receives the page image.

9. The printhead controller of claim 8 in which each of the memory devices is a dedicated, on-chip FIFO.

12. The method of claim 11 in which the first and second data are extracted substantially simultaneously.

13. The method of claim 11 that includes extracting the first data using a lossless bi-level decompression device.

14. The method of claim 11 that includes extracting the second data using a high quality lossy decompression device.

15. The method of claim 11, further including the step of temporarily storing the page image in a storage device prior to printing.

16. The method of claim 11 when performed in a printhead controller, including operating the printhead controller as a self-synchronizing pipeline.