Hewlett-packard Company

Russell Campbell

Timothy P Blair

Richard M Dow

Douglas J Mellor

Burton H Poppenga

Terrence M Shannon

Ted E Dennler

David L Lanning

Todd A Fischer

Jeff H Papke

Paul R Sorenson

James G Wendt

Charles K Keyes

Patrick W Fulghum

An imaging device and method provide memory management tasks on data of a page being composed in response to feedback generated by memory management tasks that are performed on pages in the page pipe that are waiting to be imaged. The feedback is throttled relative to memory management tasks that occur in the pipe. Advantageously, the memory management tasks are performed on the page being composed without waiting for an already composed page to finish imaging. Accordingly, page throughput of a multi-page print job is improved. The memory management tasks include compressing, relocating, and/or compressing and relocating data. Page data on which the memory management tasks are performed include raster patches, fonts, patterns, video bands, monster bands and vector bands. Atomic operations and/or a critical section locking mechanism provide collision avoidance as between the memory management tasks performed on data in the pipe and a video imaging task.

Conservation of printer memory on the composition page in response to page pipe feedback

An imaging device and method enable the freeing of memory during a punt (print overrun) avoidance operation and during a duplexing operation for enhanced page throughput. Specifically, if a first race condition threshold is met, being indicative of an estimated need to pre-rasterize a band from a page of image data for punt avoidance, and if after pre-rasterization it is determined pre-rasterization is not actually needed for punt avoidance, then the pre-rasterized band is evaluated relative to its display list for memory savings purposes for improved page throughput performance. Similarly, if a duplex condition threshold is met, being indicative of a band being part of a first side of a duplex page being processed and of an estimated need to save memory for processing of the second side of the duplex page, then the band is pre-rasterized and evaluated relative to its display list for memory savings purposes for improved duplex page throughput performance. If neither the race condition threshold nor duplex condition threshold is met, but an increased general memory savings condition threshold is met for the band, then the band is pre-rasterized for memory savings purposes.

Freeing memory in a page printer during punt protection

A memory management system usable with a client is provided. The memory defines a memory space including at least one memory buffer, and the memory buffer is defined by a set of attributes including base address and size. The memory includes a fixed-simple memory allocation, having a link, and one of a relocatable simple memory allocation coupled with the link, a head of a complex memory allocation comprising multiple simple memory allocations, or a null simple memory allocation. A memory manager is coupled with the memory and is configured to manage specific instances of memory allocation usable by a client. A memory management interface is coupled with the memory manager and is configurable to enable a client to specify a request for a relocatable memory object. Processing circuitry is coupled with the memory and the memory management interface and is operative to detect a low memory condition. The memory manager is operative to relocate the memory object from one physical location in memory to another physical location in memory to generate a sufficiently large contiguous free memory block for the client so as to overcome the low memory condition. A method is also provided.

Memory management system and method for relocating memory

A system and method produce a combined page having all of the composition of a first page plus all of the composition of a second page. Each band of the first page is pre-rasterized then saved to solitary band stores. Next each band of the second page is pre-rasterized and combined with the corresponding solitary band store to produce combined band stores. The combined band stores are then joined to produce the combined page. The combined band stores are joined by printing each combined band store in sequential location on the same page.

Simplified method to print inherited pages in a page printer

Freeing memory in a page printer during duplex processing

An imaging subsystem for a printer is configured to support multiple printer personalities. The imaging subsystem has an integrated display list that is accessed and used by all of the printer personalities. The printer implements a display list builder tool that assists each personality in posting its objects to the display list.

Integrated display list and building tool for multiple personalities

A multi-resolution capable printer includes a critical operations memory buffer for enabling critical page print operations to occur without flushing the video buffers and without waiting for returned-in memory to heal into larger free blocks. The critical operations buffer thus enables improved constant printer throughput and reduced 'pausing' during a multi-page print job. The critical operations buffer is dynamically sized to the resolution of the current page being printed. Thus, at higher resolution configurations, the critical operations buffer is reduced in size to allow the video buffers to increase in size to accommodate the higher resolution. At lower resolution configurations, the critical operations buffer is increased in size and the video buffers are decreased in size to accommodate the lower resolution. Advantageously, the total combined pre-reserved memory area utilized by the critical operations buffer and the video buffers remains constant. The critical operations buffer is utilized for large contiguous memory allocation requests, pre-rasterization operations, compressing operations, rendering character bitmaps, scaling and rotating raster objects, building vector paths, defragmenting the memory, and the like.

Memory partitioning for multi-resolution pauseless page printing

A method of operating a digital printer for producing a printed image on a print medium is described. The method is intended for use with a printer which includes at least one memory for holding an overlay pattern bit map which defines an overlay pattern at least portions of which are utilized in printing the printed image onto the print medium, and an image processor for processing 3image data used to produce the printed image. The method includes defining at least one fill area to be printed with at least a portion of the overlay pattern; reading at least a portion of the overlay pattern bit map from said memory; providing at least one boundary point which in part defines a fill area subset which serves to fill a portion of the fill area and define a portion of the printed image appearing therewithin; applying at least a portion of the overlay pattern bit map read from memory to the fill area subset; writing the fill area subset to an output buffer which stores data defining at least a portion of the printed image; and servicing the print mechanism at variable or constant paper slew rate. According to a preferred embodiment, a 3-parameter model is used to determine the incremental image processing cost of pattern processing.

Efficient pattern use in printers

A printer apparatus and method for operating a digital printer are provided which utilize a super-pixel bit map set containing a plurality of pixel pattern bit maps, each pixel pattern bit map defining the on or off condition for a plurality of individual pixels which make up a super-pixel which forms a part of a printed area, such as for gray or color shading. The method includes accepting an input value for a particular super-pixel to be printed, the input value being from one of a set of available input values defined by an input array set; providing a threshold array which defines available pixel pattern bit maps which can be used in printing super-pixels for a particular print job; producing a key array which assigns a different key identifier to each of the available pixel pattern bit maps defined by the threshold array; associating an input value with a key identifier; using the key identifier to access or build and access a suitable pixel pattern bit map for a particular super-pixel to be printed; and transferring the pixel pattern bit map to effect printing of the super-pixel being printed.

Efficient use of dither matrix based gray level patterns

Apparatus for processing and displaying binary pixel image data includes a printer for receiving image data and for presenting the image data as bilevel pixel values. The printer includes a processor for altering the received image data into an output image. A host processor stores multi-bit-per-pixel image data and further includes image processing software and data transmission circuitry coupled to the printer. The host processor compares the bilevel pixel data size and the multi-bit-per-pixel data size and, based upon a size relationship determined from the comparison, processes the multi-bit-per-pixel image data into bilevel pixel values in either the printer or the host processor so as to transmit the least amount of image data between the host processor and the bilevel printer.

Image processing load balancing for a host processor with a connected

A processor unit converts source image data to a rasterized monochrome bit map and includes a random access memory, a storage memory containing a gray scale conversion table, dithering matrices, procedures for determining destination image dithering tiling locations, scaling conversion procedures and sub routines for establishing a gray scale value array indexed to a bit mask array. The processor unit performs a method of converting source image data to a rasterized compressed monochrome bit map which involves a conversion cycle for converting source pixels to gray scale value and output position bits within the two arrays. Testing is performed to determine all of the source pixels converted to the same gray scale value, and if so, a read ahead cycle commences, reading ahead in the source pixel row for as long as the unconverted source image data bytes are the same as for those converted in the conversion cycle. The converted output position bits of the converted source pixels are dithered. Optionally, an attempt is made to generate a compressed data repeated run entry with a default to a literal run entry based upon dithering of only the converted source pixel output position bits and a count of repeating source pixels.

Method to convert bitmaps to monochrome data

A printer includes a procedure for assigning received print commands, in a page intermediate form, to page strips to be printed. The page strips are subsequently rasterized. The printer implements a method for predetermining whether the received print commands exceed an adaptively determined complexity threshold and, if so, the received print commands are rasterized immediately and stored in supplemental memory. The method includes the steps of: determining for each object to be printed on a page, in which page strip or page strips the object resides; for a portion of the object residing in a first page strip, finding a print complexity factor for the portion of the object; summing the found print complexity factor to previously found print complexity factors to determine an intermediate strip complexity factor for the page strip; providing an immediate rasterization threshold value which is varied in accordance with the amount of available supplemental memory; comparing the intermediate strip complexity factor to the immediate rasterization threshold and if it exceeds the threshold, rasterizing all objects in the first strip and storing the rastered data in the supplemental memory. The method further provides for adjustment of an amount of memory assigned to supplemental memory so as to enable more immediate rasterization when memory is plentiful.

Method and apparatus for preventing print overruns by pre-rasterizing

A packet-based communication system is described for linking a peripheral unit (PU) to the outside world via a communications link. The system includes a modular interface unit (MIU) which has a memory shared by processors in both the PU and MIU. The system employs control packets, read packets and write packets and performs a method for allocating the shared memory that optimizes memory utilization. The system determines a ratio of read to write packets required in the operation of the PU, and it ignores that ratio if the communications link will not transmit write packets. If the communication link will transmit write packets, it allocates read and write packet space within the shared memory in accordance with the ratio. The system also includes apparatus for enabling MIU configuration via user/keyboard inputs through the PU with the MIU providing the question and answer messages. This feature allows the PU to adapt to many different communication links, simply by replacement and user configuration of the MIU. The system further includes apparatus for rapidly handling network protocol headers. Those headers are stored along with the data packets and when the packet is accessed by the PU from shared memory, pointers are employed to enable access of only the data portions of such packets while ignoring the network protocol header portions.

Growing community of inventors

Boise, ID, United States of America

Russell Campbell