Hewlett-Packard Company

Hewlett-Packard Development Company, L.p.

Steven O Miller

Elden Wood

William James Allen

Jay Stephen Gondek

Thomas B Pritchard

Mark S Hickman

William B Buzbee

Mark D Lund

Ranjit Bhaskar

David M Wetchler

David E De Bellis

Daniel L Stuart

A method of printing a document having a plurality of pages in an original sequence includes determining an second sequence to print each of the pages, wherein the second equence is different than the original sequence; loading each of the pages onto cyclic multi-page transport apparatus according to the optimal sequence; and unloading the pages from the transport apparatus according to the original sequence.

Method of printing a multi-page document using a cyclical multi-page transport apparatus

A fast, raster-based, enhanced, data compression technique for the printing of compound documents, including pre-processing images in an original page description form of the data before the page data is rasterized, greatly improving compressibility. Unscaled image data is filtered before it is rasterized to the final printing resolution. The filtering specifically enables a separate, near loss-less, compression algorithm to operate on a rasterized page description with high compression ratios. A data compression technique enables a system to compress compound document using a relatively fast and simple algorithm with near loss-less print quality.

Compound document page data compression

A method of compressing a set of image data organized into a matrix of pixels includes selecting a multi-pixel block portion of the data, then performing a mathematical function on the multi-pixel block portion to generate a first result. The multi-pixel block portion is divided into at least two segments, and a function is performed on each of the segments to generate a second result and a third result. Based on a comparison of the first, second, and third results, determining whether or not to compress the multi-pixel block portion. The function may be a deviation or mean measurement and serve to determine the noise level and image detail level to determine whether to compress or divide the block into sub blocks. Sub blocks may be recursively analyzed for compression or subdivision until all sub blocks are compressed or divided into single pixels.

Image data compression method

A technique is described to greatly reduce or avoid the quantization errors that occur when mapping a relatively linear RGB color space into a greatly non-linear printer CMY color space of equal precision, avoiding the contouring or banding that occurs when printing color gradients in a non-linear printing system. The technique performs a dither-like process on the original RGB continuous tone data. The RGB values are dithered to create a range of values that, when mapped to the non-linear printer continuous tone CMY values, creates a range of CMY values that, on average, represent the correct average tone of the input RGB values. The generated CMY continuous tone values are then halftoned and printed.

Reducing quantization errors in imaging systems

Compound document page data processing

A method of automatically optimizing the controllable parameters related to producing printed material on a hardcopy output device is provided, along with a hardcopy output device configured for implementing this method. Users require different types of printed objects to have different characteristics. Specifically, business graphics need to be sharp and vivid, photographic images should look realistic, and text must be black, crisp and clear. By extracting, analyzing and conditioning data generated during a printing stream, the various regions of text, graphics and photographic images on a sheet are distinguished, characterized, and printed. The resulting hardcopy output has a custom balancing of color which is pleasing to the human eye for each type of image printed, and which has print characteristics tailored for the specific elements on the page.

Automatic optimization of hardcopy output

A method of automatically optimizing the controllable parameters related to producing printed material on a hardcopy output device is provided, along with a hardcopy output device configured for implementing this method. Users require different types of printed objects to have different characteristics. Specifically, business graphics need to be sharp and vivid, photographic images should look realistic, and text must be black, crisp and clear. By extracting, analyzing and conditioning data generated during a printing stream, the various regions of text, graphics and photographic images on a sheet are distinguished, characterized, and printed with a custom balancing of color pleasing to the human eye for each type of image printed.

Automatic optimization of hardcopy output for enhanced appearance and

A process is disclosed for controlling ink volume in liquid ink printing systems such as ink jet printers. The process examines the total ink volume per pixel as specified in source image data (typically 24-bit, three color data), i.e. before digital halftoning. For each pixel of data, the specified ink volume is compared to a selected maximum total ink volume per pixel. The maximum total ink volume is selected, depending upon the printing medium and environmental conditions, so as to provide good color coverage while avoiding curl, bleeding and other adverse effects of excessive ink volume. The source image ink volume is reduced so as to form depleted image data in which the ink volumes per pixel do not exceed the selected maximum. Preferably, a threshold ink volume also is selected, below which no ink limiting is applied, thereby avoiding washed-out images at lower ink volumes. Above the threshold, the ink volume is scaled to a value below the maximum, preferably by linear scaling.

Ink limiting in ink jet printing systems

A method for multiplying the speed-resolution product of a raster scanning or imaging device such as an inkjet printer, and a resulting pixel image data structure, are disclosed. Illustratively, a 300-dot per inch (dpi) by 600-dpi logical pixel image is mapped to a corresponding, non-overlapping physical dot image, and the printer's inkjets are fired responsive to the dot image to direct generally spherical ink droplets onto paper at 600-dpi resolution grid timing in order effectively to double the horizontal resolution of the printed pixel image, without increasing the firing rate of the print head. In order to accomplish this, and to avoid ink dot overlap, the printable pixel image is thinned before it is printed by a method that leaves no visible horizontal or vertical gaps by selectively turning off pixels within a `black` image that were on and that otherwise would result in ink dot overlap and slower print head speeds were the inkjets cycled at 600-dpi resolution timing. Pixel thinning is performed substantially without adversely affecting pixel image edge definition.

Raster imaging device speed-resolution product multiplying method and

A method is disclosed of mapping raster data input of a source data set to a destination data set, wherein the source and destination data sets have different resolutions. Initially, a resolution ratio is determined between the source data set and the destination data set. The horizontal component of the source data set is converted to the resolution of the destination data set by copying select discrete groups of the source data to form a desired number of discrete groups of the destination data. A select number of vertical, or raster, rows of the horizontally converted data set are copied to form a required number of rows, thereby completing the destination data set. Look-up tables are provided to efficiently convert the horizontal component of the source data set. An apparatus for mapping raster data input includes a computation mechanism for determining the resolution ratio, and mechanisms for converting the horizontal and vertical components of the source data set into the destination data set. Additionally, a look-up table generator is provided.

Method and apparatus for mapping printer resolution using lock-up-tables

The invented graphics images data compression method includes software which selectively compresses data on a raster-row-by-raster-row basis or on a byte-group-by-byte-group basis. The raster-row-by-raster-row basis compares bytes within adjacent raster rows and thereby detects repetitions between the rows. When data is compared on a raster-row-by-raster-row basis, the invented method records any differences as relative offset and replacement bytes. The byte-group-by-byte-group basis compares different byte groups within a single raster row, and thereby detects repetitions within the row itself.

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Vancouver, WA, United States of America

Steven O Miller