Allen L. Frazier - Eagle ID, US Jan P. Allebach - W. Lafayette IN, US
Assignee:
Hewlett-Packard Development Company, L.P. - Houston TX
International Classification:
H04N 1/40 B41J 2/47
US Classification:
358 312, 358 302
Abstract:
The data required to specify an image which is to be printed by a printing device, such as an ink-jet or laser printer, can be substantially reduced by omitting the data specifying the dot size or amplitude modulation (AM). Instead, the processor of the printing device determines the dot density in the immediate vicinity of each dot and, from that density measurement, calculates the appropriate dot size and modulates the dot size accordingly when driving the print head or print laser.
Method And Apparatus For Conservation Of Memory In A Printer Through Selective Compression Of A Display List
The method of the invention enables a printer to interpret received page description data and to generate a series of corresponding graphics commands that enable graphic objects to be printed. During the interpreting action, memory resources are allocated for storage of the graphics commands, which are then arranged into a display list. The printer's personality maintains a measure of available memory for allocation and, upon sensing a low memory level, causes a compression of the series of graphics commands in the display list to achieve a more efficient use of the available memory assets.
An improved method and apparatus for the creation and application of visual images such as textual characters is provided, which preferably makes use of a digital computer (12) and laser printer (16). In the preferred method, a desired image is developed using the computer (12), typically with specific selection of font style, image orientation and size of characters; the final image is then printed using printer (16) on a substrate (18) presenting a release surface (20). An image-removing web (22) is then applied over the printed image, causing the printed image to adhere to the web (22). The web (22) is then stripped from the substrate (18) and can be applied to any selected support surface.
Method And Apparatus For Toner Level Monitoring And Motion Sensing
David J. Arcaro - Boise ID Kenneth A. Lindblom - Boise ID Wayne E. Foote - Eagle ID Allen L. Frazier - Eagle ID
Assignee:
Hewlett-Packard Company - Palo Alto CA
International Classification:
G03G 1508
US Classification:
399 27
Abstract:
In a device including a replaceable cartridge containing a consumable material, the cartridge having at least one moving part, a system for estimating the use of consumable material from the cartridge is disclosed. The system includes an information storage medium secured to the moving part of the cartridge. A read-write head is mounted in the device in proximity with the information storage medium, and is adapted and constructed to write information on and read information from the information storage medium. The storage medium can be provided as a magnetic storage medium, which may be configured as an annular disc. The moving part can be provided as a generally cylindrical roller assembly including a drive gear. The drive gear can include an end surface to which the storage medium may be secured. The device itself can be any suitable printing device, such as a laser printer.
Resolution Transforming Raster-Based Imaging System
Allen L. Frazier - Derby KS James S. Pierson - Augusta KS
Assignee:
DP-Tek, Inc. - Wichita KS
International Classification:
H04N 140 G01D 942 G01D 1514
US Classification:
358298
Abstract:
A conventional display device, such as a marking engine for a laser printer or digital copier, having a nominal resolution (where the energy source for the display device can be selectively activated) and a predetermined threshold level for producing output image dots, is modified to a different (higher or lower) resolution or modified to produce output dots along axes different from the axes of the display device (such as for producing halftone screens on angles), by selectively activating the energy source to produce overlap areas that exceed the device threshold and thereby produce dots at positions that are not on the normal resolution positions of the device. Such threshold exceeding overlap areas may be achieved by activating the marking engine's energy source at a plurality of positions, with the energy at some positions being selectively below the threshold level for producing an output dot, but with the combined energy at the desired dot positions being above the threshold level to produce the desired dot. These overlap areas may be produced by modifying the duration that the energy source is activated, by the placement of less than full-extent energy actuation within the pixel extent, by activating the energy source multiple times within a pixel extent, by modulating the intensity of the energy source, and by modulating the shape of the energy cluster that the energy source (or energy beam) produces. For example, a 300. times.
Method And Apparatus For Compressing And Decompressing Image Data
Allen L. Frazier - Wichita KS Brent M. Bradburn - Wichita KS
Assignee:
Hewlett-Packard Company - Palo Alto CA
International Classification:
H03M 746
US Classification:
341 63
Abstract:
Image data such as text or half-tone images is compressed and decompressed. A compressor has three phases: a bit-run length phase that counts the length of each run of consecutive identical pixels; a pairs-repetition phase that compresses repeated pairs of pixel run values to one copy of the repeated pair and a repeat count; and an optional dictionary-based micro-table encoder. The micro-table, which may be used in any application calling for a least recently used (LRU) mechanism, has multiple qualification layers, with elements within a qualification layer being promoted to the next higher qualification layer upon the occurrence of a table hit for that element, and being demoted to the next lower qualification layer by being bumped by elements promoted up from below. The result is a table that is weighted both by frequency and recency of hits.
System And Method For Enhancing Graphic Features Produced By Marking Engines
Gray scale input data, derived from continuous tone data, is transformed into pulse patterns for driving a marking engine so that a variety of marks of different sizes and shapes are formed in any given pixel region. Gray scale input data is arranged (received) as an array of pixels, in the native engine resolution, including multi-bit per pixel gray level values. A pixel in the array is analyzed in a transformation (window) to determine the pulse pattern output based on the gray level value of the current pixel and on the gray level values of adjacent vertical and horizontal pixels. The pulse pattern output for driving the marking engine in the current pixel location is adjusted by the transformation to produce sub-pixel sized marks of various shapes, sizes, positions, and orientations that, in combination with neighboring marks so produced, provides for the flexible production of marking patterns that contain a number of gray scale levels substantially exceeding the number of gray scale levels contained in the input data, and that enhance the simulation of graphic features produced. The transformation flexibly selects from an optimized subset of pulse patterns available to produce the most accurately calibrated tones and features based on the input data. Hence, gray scale input data is transformed into a pulse pattern output for driving a marking engine.
Interleaving Vertical Pixels In Raster-Based Laser Printers
Allen L. Frazier - Derby KS James S. Pierson - Augusta KS
Assignee:
DP-Tek, Inc. - Wichita KS
International Classification:
H04N 121
US Classification:
358298
Abstract:
The output of a conventional laser printer having a resolution of 300. times. 300 dots per inch (DPI), and a predetermined threshold level for forming image dots, is enhanced by selectively providing interleaved image dots between the normal scan lines of the laser printer. Such interleaved image dots between scan lines may be achieved by appropriately energizing the two pixels directly above and directly below that desired interleaved dot, with the energizations at one or both pixels being selectively below the threshold level for producing a dot on the scan line, but with the combined energization at the desired interleaved point being above the threshold level to produce the desired interleaved dot. An input 600. times. 600 bit map may be stored in a random access memory, and three vertically aligned bits from one main scan lne and adjacent 600 DPI lines above and below are drawn from the RAM and are supplied to a logic and video output circuit which produces variable pulse width modulated pulses to the laser printer to produce the enhanced image.