Hewlett-packard Company

Hewlett-packard Development Company, L.P.

Thomas B Pritchard

Jay Stephen Gondek

Mark D Lund

Steven O Miller

David J Lowe

Winthrop D Childers

William James Allen

Kevin R Hudson

Richard I Klaus

Douglas L Franz

Eva-Maria Moon

Ronald R Paulsen

Shane D Wall

Eric P Ross

Casey D Hoekstra

An apparatus includes a first processing device to perform halftoning on a first set of values corresponding to a first set of pixels and a second processing device to perform halftoning on a second set of values corresponding to a second set of pixels, with ones of the first set of pixels located adjacent to the second set of pixels and with ones of the second set of pixels located adjacent to the first set of pixels. The apparatus further includes a bus arranged for transferring a third set of values, from the halftoning of ones of the first set of values corresponding to the ones of the first set of pixels, to the second processing device and for transferring a fourth set of values, from the halftoning of ones of second set of values corresponding to the ones of the second set of pixels, to the first processing device.

System for improving the speed of data processing

Tools for directing a collection of light emitting devices toward pixel locations to make an image are disclosed. A pixel location is a light emitting device target at least twice during a given frame, and each light emitting device in the collection is directed toward at least two different pixel locations during the frame. Adjacent light emitting devices may be directed toward adjacent pixel locations or toward nonadjacent pixel locations.

Light emitting device projection methods and systems

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

Multiple algorithms are applied to expand input image data of a variety of lower resolutions to output image data of a variety of higher resolutions with enhanced text quality, particularly in the black datapath controlling an output device such as an inkjet or laser printer. Enhancement techniques include edge smoothing, bit stripping for large drop weight pens, and drop-weight based ink depletion. Embodiments provide algorithms that convert 600&times;600 dpi input resolution data to 1200&times;600 dpi output resolution image data or 300&times;300 to 600&times;300 dpi resolution (i.e., asymmetric 2:1 ratio resolution conversion along mutually perpendicular axes), including text edge smoothing, while causing minimal change to gray scaled (halftoned) data within images. The techniques can be applied to other resolutions as well. Some embodiments include unidirectional bitstripping that preserves 1200 dpi edges while applying output pixels at only 600 dpi from 1200 dpi resolution output image data. Some embodiments include drop-weight based depletion to adjust the average ink flux to 32 ng per {fraction (1/600)}th inch cell, thereby preventing excess ink application at high output resolutions, e.g., 1200&times;600 dpi. In various embodiments, operations are performed in hardware modules and/or performed cooperatively as an integrated process to meet system throughput requirements.

Pixel depletion technique

Multiple algorithms are applied to expand input image data of a variety of lower resolutions to output image data of a variety of higher resolutions with enhanced text quality, particularly in the black datapath controlling an output device such as an inkjet or laser printer. Enhancement techniques include edge smoothing, bit stripping for large drop weight pens, and drop-weight based ink depletion. Embodiments provide algorithms that convert 600&times;600 dpi input resolution data to 1200&times;600 dpi output resolution image data or 300&times;300 to 600&times;300 dpi resolution (i.e., asymmetric 2:1 ratio resolution conversion along mutually perpendicular axes), including text edge smoothing, while causing minimal change to gray scaled (halftoned) data within images. The invention applies to other resolutions as well. Some embodiments include unidirectional bitstripping that preserves 1200 dpi edges while applying output pixels at only 600 dpi from 1200 dpi resolution output image data. Some embodiments include drop-weight based depletion to adjust the average ink flux to 32 ng per {fraction (1/600)}th inch cell, thereby preventing excess ink application at high output resolutions, e.g., 1200&times;600 dpi. In various embodiments, operations are performed in hardware modules and/or performed cooperatively as an integrated process to meet system throughput requirements.

Multiple data manipulation algorithms for text quality enhancement

The present disclosure relates to a replaceable printing component for an ink-jet printing system having at least one replaceable printing component. The replaceable printing component includes an electrical storage device responsive to printing system control signals for transferring information between the printing component and the ink-jet printing system. The electrical storage device includes a storage portion containing a plurality of data fields associated with the replaceable printing component. Included in the electrical storage device is a plurality data values stored in each of the plurality of data fields. Also included is a control portion responsive to control signals for selectively transferring a block of data values having a preselected size between the ink-jet printer and the storage portion. The plurality of data fields are sized and arranged in the storage portion to ensure each of the plurality of data fields is transferred in a single data transfer between the ink-jet printer and the storage portion.

Method and apparatus for transferring data between a printer and a replaceable printing component

In an error diffusion process for an inkjet printer, a look-up table is indexed by an input color tone, with entries for base output level, base level error term, threshold error term, and whatever other data may be relevant. This table may be embodied in a conventional memory or software code. The base output level corresponds to the number of ink drops to be ejected by the inkjet print for particular ink colors, the base level error term reflects the error between the input and output of the look-up table, and the threshold error term is subtracted from the total error for the pixel if the base output level is incremented by one.

Table based fast error diffusion halftoning technique

A method adapted for implementation in a computer system for correcting and half toning color data in a list of colors is provided. Starting with the first color in the list, color corrections are performed. Using traditional half toning methods, descriptions of the resulting printable dots for each position in the halftone matrix for that color are determined. Color corrections and half toning are repeated for each of the colors in the list. A lookup table is compiled. As each pixel of the image from which the list of colors was compiled is encountered, the printable dots are determined by reference to the lookup table.

Computerized memory mapping method for transforming color data

A method for reducing the volume of ink applied to high-density print regions by depleting certain pixels in these regions avoids problems associated with excessive ink, improves economy, and yet retains print quality. Pixels located along the edges of high-density regions are identified and not depleted, thus preserving the sharp image demarcations characteristic of high quality printing. An upper bound for the percentage of depleted pixels may be chosen. A two-dimensional depletion table having certain entries designated as potential depletion candidates is tiled across a pixel image to be depleted. The designated entries are spaced apart within the table. If a pixel in the image is a candidate to be depleted according to the depletion table and if it is not an edge pixel, then it is depleted.

Dot depletion in pixel-array printing

A data compression and decompression procedure for a serial printer handles data from a print swath that includes Y rows of pixel data. The procedure divides the print swath into N microbands of pixel data, with each microband including y rows of pixel data (where y.times.N.gtoreq.Y). The procedure compresses each microband of the pixel data by breaking up the microband into microblocks and comparing data in each microblock with a seed value to arrive at a compressed microblock based upon data differences from the seed value. Each microblock comprises a block of pixel data that is m bits wide by y rows high, where m is a small fraction of M bits of pixel data that are printable by the printhead across a sheet. All microbands of a swath are subjected to the data compression procedure so as to create positionally corresponding sets of compressed data microblocks for all of the microbands. In preparation for printing, the procedure decompresses all N microbands of raster data by acting on each set of compressed microblocks to recreate a set of N microbands of decompressed pixel data. The procedure then feeds the N microbands of decompressed raster data, in parallel, to the printhead.

Method and apparatus for compression and decompression of data used by a

Digital integrated circuit testable input/output pad logic includes modified output driver logic and a latch for storing a test bit provided externally at the I/O pad terminal. The output driver logic selects either the normal pad output signal (O) for output during normal operation, or the stored test bit (S) or its complement (S') for output during a test operation. The output driver logic and latch are controlled by control logic signals (DP,SP,NDN,LS,NLS,NSN) derived from common tri-state (NTR) and latch (NTM) test signals provided externally at dedicated test pins (NTR,NTM). The control logic signals are provided over a bus to all similar testable I/O pads for testing all testable I/O pads within the IC under control of the two test signals.

Testing integrated circuit pad input and output structures

The invented data compression/decompression methods, device, and resulting data structures, operate by noting likenesses and differences between portions of data, and effecting data storage only with respect to the noted differences. The compression method arranges the data, compares portions of the data, and provides a flag to signal changes between adjacent data portions. The decompression method reads a portion of data, identifies whether the flag signals any changes in the data, and if so, reads a subsequent portion of data; but if no changes are signaled, then the first portion of data is duplicated. The invented device includes memory, a structure for storing data in the memory, data stored in the memory with flags to signal changes in the data, and structure for accessing and using the stored data. The invented data structure includes data divided into predetermined sections, and flags associated with the sections to signal changes within the sections.

Data compression/decompression method, device and resulting data

In a color ink jet printing system, an image superpixel (84, 86, 88) consists of a 2 by 2 array of cells (1-4), each cell corresponding to a pixel area on the substrate (80). Each pixel (55) of graphics data is processed to form a 2 by 2 array of bit image data (40), for printing a corresponding superpixel image (68). A superpixel configuration (86), indicating cell location and color of drops of ink for forming a superpixel image, is defined for each desired image color. Superpixel configurations control printing so that drops of ink (Y,M,C) are deposited only an a diagonally adjacent pair of cells (1,4), with no more than two drops of ink per cell, and no more than three drops of ink per superpixel. This superpixel strategy provides for printed images (62,64) perceivable as having the desired image color and having good color saturation, while minimizing bleed across color field boundaries (66).

Ink jet color graphics printing

The protection circuit of the invention connects differentiated grounds in an electronic system either by a single diode, or by two diodes arranged in a back-to-back, parallel fashion. The differentiated grounds may include a chassis ground, a logic ground and an earth ground. The circuit locally connects two of the differentiated grounds, thereby providing a low inductance path for the fast discharging of electrostatic charge build-ups, with the diode(s) therein providing the electrical separation necessary to provide proper local isolation between the interconnected grounds to enable filtering out of electromagnetic interference potentials.

Growing community of inventors

Brush Prairie, WA, United States of America

Thomas B Pritchard