JP4389199B2 - Printer system - Google Patents

Description

  The present invention relates to a technique for performing image processing in parallel using a plurality of processors.

  Generally, in a laser printer system, a print object described in PDL (page description language) is developed into a print image by a RIP (raster image processor), and sequentially sent to a print engine for each scan line (raster) for printing. Execute.

  At this time, if all the print images are developed and stored for one page, a very large memory area is required. Therefore, it is common to divide one page into bands composed of a plurality of scanning lines and develop a print image in that unit.

In order to perform such band-by-band expansion processing at high speed, a configuration has been proposed in which each band is assigned to each of a plurality of processors and the expansion processing is performed in parallel (Patent Document 1).
JP 2003-51019 A

  When the RIP is provided in the host device, the developed print image needs to be transmitted to the printer side. In this case, since the print image has a large amount of data, it is usual to adopt a framework in which compression processing is performed before transmission by the host device and decompression is performed on the printer side.

  Here, when the host device or the printer includes a plurality of processors, a configuration in which each band is assigned to each of the plurality of processors and compression processing or decompression processing is performed in parallel as in Patent Document 1 can be considered.

  However, in such a method of parallelizing in units of bands, data of individual scanning lines (individual bands) is not parallelized. Therefore, there remains a problem that the time required for obtaining the processing result for the first one scanning line (one band) is the same as when processing is performed by a single processor. In other words, despite the parallelization by a plurality of processors, no advantage is obtained with respect to the rise until the actual printing is executed.

  In addition, in the case of the method of parallelization in units of bands, in order to improve the throughput, a memory area for storing the processing results for the number of processors so that each processor can execute processing in parallel for the band allocated to itself. Is required. Therefore, if the number of processors is increased to increase the degree of parallelism, there arises a problem that the memory area necessary for processing increases accordingly.

  Therefore, the present invention aims to increase the processing speed for each scanning line, and in particular to shorten the time (rise time) required until the first processing result is obtained.

  Another object of the present invention is to realize an improvement in throughput while suppressing a necessary memory area when parallelized by a plurality of processors.

  An image processing apparatus of the present invention is an image processing apparatus that performs image processing in parallel using a plurality of processors, and for each of at least one scanning line constituting an image, each scanning line is divided into a plurality of partial regions. In this case, at least one of the plurality of processors is assigned to each of the partial areas, and image processing is performed in parallel. According to such a configuration, the image processing time for each scanning line can be shortened. In particular, by shortening the image processing time for the first scanning line, the time from the start of image processing to the end of the first scanning line image processing and the use of the processing result Can be shortened, and a flow of image processing that rises quickly can be realized.

  Preferably, the image processing is image compression processing or image expansion processing.

  Preferably, the memory area for storing the image processing result is provided with memory areas corresponding to the number of scanning lines smaller than the number of the plurality of processors.

  Preferably, the apparatus further comprises means for transferring corresponding image processing results to a subsequent processing apparatus in the arrangement order of the partial areas in the scanning line.

  Preferably, the image processing apparatus further comprises means for transferring the image processing result to a subsequent processing apparatus when the image processing results for one scanning line are obtained.

  According to such a configuration of the present invention, if there is a memory area having a capacity for storing an image processing result for at least one scanning line, it is possible to improve the throughput of the image processing by parallelization.

  A printer control apparatus according to the present invention is a printer control apparatus having a function of performing image processing in parallel using a plurality of processors, and for each of at least one scan line constituting an image, each scan line is divided into a plurality of partial areas. And assigning at least one of the plurality of processors to each of the partial areas, performing image compression processing in parallel, and transmitting the compressed data corresponding to each partial area to the printer device. Features.

  The printer device of the present invention is a printer device having a function of performing image processing in parallel using a plurality of processors, and for each of at least one scan line constituting an image, each scan line is divided into a plurality of partial areas. In this case, the compressed partial data corresponding to each of the partial areas is received from the host device, and at least one of the plurality of processors is assigned to the compressed partial data to perform image decompression processing in parallel. .

  The printer system according to the present invention includes a host device and a printer device configured to be communicable with the host device, and each of the host device and the printer device performs image processing in parallel using a plurality of processors. A host system having a function, wherein at least one scanning line constituting an image, the host device divides each scanning line into a plurality of partial areas, and each of the partial areas includes a plurality of processors. Image compression processing is performed in parallel by assigning at least one, and compressed data corresponding to each partial area (hereinafter referred to as “compressed partial data”) is transmitted to the printer device, and the printer device forms an image. For at least one scan line, the portion when each scan line is divided into a plurality of partial regions Receiving the compressed partial data corresponding to the respective frequency from the host device, and performs image expansion processing in parallel by assigning at least one of the compressed partial data to the plurality of processors.

  The image processing method of the present invention is an image processing method for performing image processing in parallel using a plurality of processors, and for each of at least one scanning line constituting the image, each scanning line is divided into a plurality of partial regions. In this case, at least one of the plurality of processors is assigned to each of the partial areas, and image processing is performed in parallel.

  The image processing method of the present invention can be implemented by a computer, and a computer program therefor can be installed or loaded on the computer through various media such as a CD-ROM, a magnetic disk, a semiconductor memory, and a communication network. . It also includes the case where a computer program is recorded and distributed on a printer card or printer option board.

  According to the present invention, it is possible to increase the throughput while increasing the processing speed of individual scanning lines constituting an image and suppressing a necessary memory area.

(First embodiment)
FIG. 1 is a block diagram showing a hardware configuration of a printer system 1 according to an embodiment of the present invention. As shown in FIG. 1, the printer system 1 may be any of a host device 10 and a communication network (LAN, Internet, dedicated line, packet communication network, a combination thereof, etc., and includes both wired and wireless. ), A printer device (image forming device) 20 configured to be communicable with the host device 10.

  The host device 10 includes hardware such as a main CPU, a parallel processing unit 15 including parallel processors 11 to 14, a ROM, a RAM, a user interface, and a communication interface. In the present embodiment, the parallel processing unit 15 includes four processors 11 to 14, but the number of processors can be any number greater than or equal to 2 (for example, 8) depending on the design.

  The host device 10 includes a printer driver unit 16 as a normal control function necessary for causing the printer device 20 to execute printing.

  The printer driver unit 16 has the same functional configuration as that of a normal printer driver, and is described in a predetermined printer control language such as a postscript in response to a print request from an application program operating on the host device 10, for example. RIP means for generating a raster image based on print target data, image processing means for creating a print image by performing predetermined image processing (screen processing or the like) on the raster image, and the like.

  However, as will be described later, the printer driver means 16 of the present embodiment uses a parallel processing unit 15 to perform compression control means 17 for executing image compression processing in parallel on individual scanning lines constituting a print image. This is different from the conventional configuration in that a transfer means 18 for transferring the compression processing result by the parallel processing unit 15 to the printer device 20 is provided (see FIG. 2).

  Each of these means is functionally realized by the main CPU executing a program stored in a ROM or RAM in the host device 10 or an external storage medium.

  The printer device 20 includes a power mechanism unit and a printer controller 26.

  The power mechanism unit includes a paper feed mechanism that supplies paper into the printer, a print engine that performs printing, and a paper discharge mechanism that discharges paper outside the printer. As the print engine, for example, a serial printer that prints in units of characters, such as an inkjet printer or a thermal transfer printer, a line printer that prints in units of lines, a page printer that prints in units of pages, and the like are used. it can.

  The printer controller 26 includes a main CPU, a parallel processing unit 25 including processors 21 to 24, a ROM, a RAM, a user interface, a communication interface, and the like. In the present embodiment, the parallel processing unit 25 includes four processors 21 to 24. However, the number of processors can be any number of 2 or more (e.g., 8) depending on the design. In addition, the power mechanism unit may include an independent CPU. In this case, the CPU of the power mechanism unit communicates with the main CPU of the information processing unit via a predetermined communication path to control the print engine. Thus, a printing operation is performed.

  The printer controller 26 has the same functional configuration as a printer controller in a normal printer. For example, the printer controller 26 receives a command or data from the host device 10 and stores it in a reception buffer, and controls the power mechanism unit to execute printing. The engine control means etc. to be provided are provided.

  However, as will be described later, the printer controller 26 of the present embodiment uses the parallel processing unit 25 to perform decompression control means 27 that performs decompression processing in parallel on individual scanning lines, and decompression processing by the parallel processing unit 25. This is different from the conventional configuration in that it includes transfer means 28 for transferring the results to the print engine in the order used for printing (see FIG. 2).

  Each of these means is realized by the main CPU executing a program stored in a ROM or RAM in the printer device 20, an external storage medium, or the like.

  Hereinafter, the printing process in the printer system 1 will be described with reference to the flowcharts shown in FIGS. In addition, each process (including the partial process to which the code | symbol is not provided) can be arbitrarily changed in order within the range which does not produce contradiction in the processing content, or can be performed in parallel.

(Processing in the host device 10: FIGS. 3 to 5)
When the printer driver unit 16 receives a print request from an application program operating on the outside or the host device 10, the printer driver unit 16 transmits a print instruction command to the printer device 20 (printer controller 26), and also to the RIP unit or the like. To start the process.

  When the RIP unit receives an instruction to start processing, the RIP unit generates a raster image based on print target data described in a predetermined printer control language such as a postscript received from the application program. If the print target data can be received in the form of a raster image from an application program or the like, the processing by the RIP unit can be omitted.

  The image processing means performs predetermined image processing (screen processing or the like) on the generated raster image, generates a print image, and stores it in a predetermined area of the RAM.

  The compression control unit 17 selects lines in the main scanning direction (hereinafter simply referred to as “scanning lines”) constituting the generated print image in the order of the sub scanning direction (step S100). The main scanning direction and the sub-scanning direction are determined based on scanning in the printer device 20.

  Next, the compression control means 17 divides the selected scanning line into a plurality of partial areas (S101). Hereinafter, such a partial area is referred to as a “channel”, and channel numbers are added in order of arrangement in the scanning line to identify each channel (see FIG. 10).

  Next, the compression control means 17 specifies the head position of a print image (hereinafter referred to as “partial data”) included in each channel in the selected scanning line (step S102). For example, when one scan line is 2048 pixels, one scan line is equally divided into four partial areas according to the number of processors, and the first pixel, the 512th pixel, the 1024th pixel, and the 1536th pixel are respectively partial. It may be possible to specify the head position of data.

  Note that steps S101 to S102 can be omitted if channels are defined in common for all scanning lines and the head position of partial data of each channel is specified in advance.

  Next, the compression control means 17 assigns at least one of the processors 11 to 14 to each of the plurality of channels (step S103). Specifically, a combination of a channel and a processor is fixedly assigned, such as a processor 11 for channel 1 and a processor 12 for channel 2.

  Next, the compression control means 17 determines whether or not the allocated processor can process new data. If the allocated data can be processed, the compression control means 17 passes the head position of the corresponding partial data to the allocated processor, and the partial data Is read out (step S104).

  Here, the case where the processor can process new data is a case where the processor can newly write the next processing result. As a determination method, for example, when an output buffer writable by each of the processors 11 to 14 has a capacity corresponding to the processing result of one partial data, whether or not new writing can be performed depending on whether or not the processing result has been transferred. Therefore, a configuration can be considered in which a transfer end flag indicating whether or not the processing result has been transferred for each processor is prepared, and whether or not the processor can process new data based on the flag.

  Next, when there is an unselected scan line among the scan lines constituting the generated print image, the compression control unit 17 returns to Step S100 (Step S105).

  When each of the processors 11 to 14 of the parallel processing unit 15 receives the start position and read instruction of the partial data from the compression control means 17 (step S200: YES), it starts from the predetermined area of the RAM storing the generated print image. Partial data is read based on the position (step S201).

  Then, a predetermined compression process is performed on the read partial data to generate compressed partial data (step S202), and the compressed partial data is written in its own output buffer (step S203). As the predetermined compression processing, various conventional compression algorithms can be adopted depending on the design. For example, if the print image is binary data, JBIG (Joint Bi-level Image Experts Group). It is conceivable to adopt an algorithm.

  The transfer means 18 cyclically selects a processor corresponding to the channel in the order of channel arrangement (step S300).

  Next, when the partial data compression processing is completed in the selected processor and the printer device 20 (printer controller 26) can receive the compressed partial data (step S301: YES), the transfer means 18 The compressed partial data is transferred from the output buffer of the processor to the printer device 20 (printer controller 26) (step S302). At this time, predetermined boundary information is added and transferred at the end (or first) of the compressed partial data so that the boundary of the compressed partial data can be detected.

  Next, when the transfer of the compressed partial data is completed, the transfer unit 18 turns on the transfer end flag for each processor of the processor (step S303). The per-processor transfer end flag of the processor is returned to OFF when the compression control means 17 gives a read instruction to the processor.

  Next, the transfer means 18 returns to step S300 when not all the compressed partial data has been transferred for the generated print image (S304).

  According to such a configuration, the compression processing is performed in parallel for each channel constituting one scan line (that is, for each partial data), so the compression processing time for each scan line is shortened. be able to. In particular, since the compression processing time for the first scan line is shortened, the compression processing for the first scan line is completed after the compression processing for the print image is started, and the processing result is the printer device 20 (printer controller 26). It is possible to shorten the time until the data is transferred to (), and it is possible to realize a compression process (and thus a print process) that starts quickly.

(Processing in the printer 20: FIGS. 6 to 8)
When the command received by the receiving unit is a print instruction command, the printer controller 26 controls the power mechanism unit by the engine control unit to prepare for printing, and instructs the expansion control unit 27 and the like to start processing. To do.

  When receiving the processing start instruction, the decompression control means 27 assigns at least one of the processors 21 to 24 to the compressed partial data (channel) to be read next from the data reception buffer (S400).

  Specifically, a combination of a channel and a processor is fixedly assigned, such as a processor 21 for the compressed partial data of channel 1 and a processor 22 for the compressed partial data of channel 2.

  Here, it is desirable to configure the data reception buffer as a FIFO type buffer (or by a FIFO type memory) on the RAM, for example. In this case, as described above, since the transfer means 18 of the host device 10 is configured to transfer the compressed partial data to the printer device 20 (printer controller 26) in the order of the channels, the compressed portion data in the data reception buffer is transferred. Writing / reading is also the order of channels. Therefore, the decompression control means 27 can specify which channel the compressed partial data to be read out next corresponds to, and can assign a fixed combination of processor and channel.

  Next, the decompression control means 27 determines whether or not the allocated processor can process new data, and if possible, instructs the reading of the compressed partial data from the data reception buffer (step S401).

  Here, for example, when the output buffer writable by each of the processors 21 to 24 has a capacity corresponding to one partial data, the above determination can be made based on the transfer end flag in the same manner as the compression control means 17. However, as will be described later, since transfer processing is performed in units of scan lines by the operation of the transfer means 28, there is no need to prepare a transfer end flag for each processor, and the above determination is made for the processor assigned to the first channel of the scan line. You only have to do it.

  Next, when there is compressed partial data that has not been decompressed, the decompression control means 27 returns to step S400 (step S402).

  When each processor 21 to 24 of the parallel processing unit 25 receives an instruction to read compressed partial data from the expansion control unit 27 (step S500: YES), the compressed partial data at the read position of the data reception buffer is read (step S501). . Each processor can identify the read start / end position of the compressed partial data by detecting the boundary information added to the compressed partial data.

  Next, each of the processors 21 to 24 executes a predetermined decompression process on the read compressed partial data, generates corresponding partial data (step S502), and stores the partial data in its own output buffer. (Step S503). The decompression process needs to employ the decompression process corresponding to the compression algorithm employed in the parallel processing unit 15 of the host device 10.

  The transfer unit 28 selects scanning lines in the order of the sub-scanning direction in order to transmit data in the order used for printing (S600).

  Next, the transfer unit 28 determines whether or not the partial data for one scan line is stored in the output buffer of each processor in a state where all the partial data for the selected scan line is expanded (S601).

  When it is determined that all the data is stored in an expanded state, the data is transmitted in the order in which the selected scanning lines are used for printing in the order in which the channels are arranged. Data is read out and transferred to the print engine (S602).

  When the transfer of the data for one scanning line is completed, the transfer unit 28 sets the transfer end flag to ON (S603). Note that the transfer end flag is turned OFF when the print control unit gives a read instruction to the processor of the channel 1 for the next line.

  If there is an unselected scan line for the generated print image, the process returns to S600 (S604).

  According to this configuration, since the decompression process is executed in parallel for each channel constituting one scan line (that is, for each compressed partial data), the decompression process time for each scan line is shortened. can do.

  In particular, since the decompression time of the first scan line is shortened, the decompression process is completed for the first scan line after the decompression process of the compressed print image is started, and the processing result is transferred to the print engine. It is possible to shorten the time until the image is processed, and it is possible to realize a decompression process (and thus a print process) that starts quickly.

  Furthermore, when the partial data for one scanning line is prepared in the output buffer of each processor, it is transferred to the printing engine, and when the transfer is completed, the next line is expanded, that is, synchronized in units of scanning lines. Since the decompression process and the transfer process are performed, if there is a memory area with a capacity of at least one scan line as a memory area for storing partial data as a decompression process result (specifically, each processor has If the capacity of the output buffer is equal to or larger than the memory capacity for one scanning line / the number of processors), it is possible to improve the throughput by parallelization.

  In other words, when one processor is assigned to one scan line (or one band) and processed in parallel as in the prior art, the number of scan lines is the same as the number of processors as the memory area for storing the decompression processing result. If there is no memory area for the number of bands (or the number of bands), the effect of parallelization according to the number of processors cannot be obtained, whereas one processor is assigned to one partial data for parallel processing as in this embodiment. In this case, it is sufficient that each processor has a memory area corresponding to partial data, and it is not necessary to prepare a memory area for one scanning line for each processor. Even when only a small number of memory areas can be used, the effect of parallelization according to the number of processors can be obtained. It can be.

  For example, by parallelizing decompression processing, (expansion processing time of one scan line) ≈MAX {expansion processing time of compressed partial data of each processor}, by providing an appropriate number of processors, Elongation processing time) <(time required for printing one scanning line in the print engine), and in real time even for a laser printer or the like that needs to continuously supply the print data for each line to the engine at a constant speed Can respond.

(Modification of transfer means 28: FIG. 9)
In the configuration of the transfer means 28, each processor cannot perform the decompression process for the next scan line unless the data for one scan line is prepared. Therefore, the decompression process has the effect of parallelization according to the number of processors. However, the decompression process and the transfer process to the print engine cannot be executed in parallel.

  Therefore, in this modification, instead of the transfer means 28, a FIFO type transfer buffer, a first transfer means 281 for transferring from the output buffer of each processor to the transfer buffer, and a first transfer from the transfer buffer to the print engine. By providing the second transfer means 282, the decompression process and the transfer process to the print engine can be executed in parallel. The transfer buffer can be configured, for example, on a RAM or as a dedicated FIFO type memory. The transfer units 281 and 282 are realized by the main CPU executing a program stored in a ROM or RAM in the printer device 20 or an external storage medium.

  Specifically, the first transfer unit 281 selects scan lines in the order of the sub-scanning direction in order to transmit data in the order used for printing (S700).

  Next, the first transfer unit 281 selects channels for the selected scanning lines in the order used for printing, that is, in the order of arrangement (S701).

  Next, the first transfer means 281 determines whether or not the partial data is stored in an expanded state in the output buffer of the processor corresponding to the selected channel (S702). If it is determined that the data is stored, the partial data is read from the output buffer of the processor corresponding to the selected channel and stored in the transfer buffer (S703), and the transfer of the processor corresponding to the selected channel is completed. The flag is turned ON (S704). Note that the transfer end flag of each processor is returned to OFF when the decompression control means gives a read instruction to the processor.

  Next, if there is an unselected channel for the selected scanning line, the first transfer means 281 returns to S701 (S705), otherwise, if there is an unselected scanning line, The process returns to S700 to select a scan line (S706).

  On the other hand, the second transfer means 282 determines whether or not data for one scanning line is stored in the transfer buffer (S800), and if it is determined that the data is stored, the data for one scanning line is determined. Is transferred to the print engine (S801). Since partial data is stored in the FIFO type transfer buffer in the order used for printing by the first transfer means, the second transfer means 282 reads the data from the transfer buffer in order and transfers it. It can be transferred to the print engine in the order used.

  In the configuration of such a modified example, each processor can start the decompression process for the next compressed partial data at the stage when the partial data that is the processing result of the processor is transferred to the transfer buffer. It is possible to execute the decompression process in parallel with the transfer process to the engine (process by the second transfer unit).

(Other)
The present invention is not limited to the above-described embodiment, and can be variously modified and applied. For example, the present invention can be applied to a system other than a printer system as long as the system compresses / decompresses an image.

  For example, in the above-described embodiment, the printer device 20 includes the parallel processing unit 25 and the printer controller 26. However, the present invention is not necessarily limited to such a configuration. For example, the parallel processing unit 25 and the printer controller 26 may be configured as external devices that can be connected to the printer device 20. Furthermore, the parallel processing unit 25 and the printer controller 26 may be configured as devices that can be connected to the host device 10 according to a standard such as a PCI bus. When the parallel processing unit 25 is connected to the host device 10, the functions of the printer controller 26 may be realized by the main CPU or the like of the host device 10.

  For example, in the above-described embodiment, the configuration in which one scan line is equally divided into partial areas according to the number of processors has been described. However, for example, the size of the partial area to be allocated is changed according to the processor specifications and the like. It is not necessary to divide. Further, the number of divisions (number of channels) of the partial area is not necessarily equal to the number of processors.

  Further, for example, in the above-described embodiment, the configuration in which the combination of the channel and the processor is fixedly described has been described. However, for example, a processor that has finished processing may be allocated to the next channel. In this case, the correspondence between the processor and the channel may be different for each scan line. Note that not only the processors of the parallel processing units 15 and 25 but also the main CPU may be assigned channels to execute parallel processing.

  Further, for example, in the above embodiment, the configuration in which the processors 11 to 14 read partial data from the RAM has been described. However, for example, the host device 10 transfers means for transferring partial data from the RAM to the processors 11 to 14 (for example, DMA transfer means). ), The compression control means may instruct the means. In this case, the processors 11 to 14 execute processing upon receiving the transfer from the means. Similarly, for example, when the printer device 20 includes means for transferring compressed partial data from the data reception buffer to the processors 21 to 24 (for example, DMA transfer means), the decompression control means may instruct the means. The processors 21 to 24 execute processing in response to the transfer from the means.

  Further, for example, in the above embodiment, the case where the output buffers writable by each of the processors 11 to 14 (processors 21 to 24) has a capacity corresponding to the processing result of one partial data has been described. It may be possible to write to an output buffer that is larger than the capacity. In this case, each processor can perform compression processing (decompression processing) one after another as long as the capacity of the output buffer permits. In addition to the configuration provided in the parallel processing unit, the output buffer of each processor may be configured using a part of the RAM of the host device 10 or the printer device 20.

  Further, for example, in the above-described embodiment, the configuration in which the parallel processing is performed for all the scan lines of the print image has been described. However, if the present invention is applied to at least one scan line constituting the print image, the compression processing time for the scan line is determined. / An effect of shortening the extension processing time can be obtained.

  Further, for example, in the above embodiment, the configuration in which the transfer unit 18 sequentially transfers the compressed partial data to the printer device 20 has been described. . At this time, for example, the compressed partial data may be stored once in the RAM and then transferred.

  Further, for example, in the above-described embodiment, the configuration in which the transfer unit 18 transfers the channel in the order of the channels has been described, but the configuration in which the channel identification information is added to the compressed partial data and transferred to transfer in a different order. It can also be. In this case, the expansion control means 27 can determine the processor to be assigned based on the identification information.

  Further, for example, in the above-described embodiment, the transfer unit 28 (or the second transfer unit 282) has been described with respect to a configuration in which data is transferred to the print engine when data for one scanning line is prepared. Depending on the situation, the data may be transferred to the print engine without waiting for the data for one scanning line to be prepared or when the data for a plurality of scanning lines has been prepared.

1 is a block diagram illustrating a hardware configuration of a printer system according to an embodiment of the present invention. 2 is a block diagram showing a functional configuration diagram of a printer driver means 16 and a printer controller 26. FIG. 4 is a flowchart showing processing contents of a compression control means 17; 3 is a flowchart showing processing contents in a parallel processing unit 15. 4 is a flowchart showing processing contents of a transfer means 18; 4 is a flowchart showing the processing contents of an expansion control means 27. 4 is a flowchart showing processing contents in a parallel processing unit 25. 3 is a flowchart showing processing contents of a transfer means 28. 10 is a flowchart showing processing contents in a modification of the transfer means 28. It is a figure for demonstrating a channel.

Explanation of symbols

  DESCRIPTION OF SYMBOLS 1 Printer system, 10 Host apparatus, 11-14 Processor for parallel processing, 15 Parallel processing unit, 16 Printer driver means, 17 Compression control means, 18 Transfer means, 20 Printer apparatus, 21-24 Processor for parallel processing, 25 Parallel processing Unit, 26 printer controller, 27 expansion control means, 28 transfer means

Claims (1)

A printer system that includes a host device and a printer device configured to be able to communicate with the host device, and each of the host device and the printer device has a function of performing image processing in parallel using a plurality of processors. And
The host device
When at least one scan line constituting the image is divided into a plurality of partial areas, at least one of the plurality of processors of the host device is assigned to each of the partial areas, and the images are arranged in parallel. a compression control unit intends row compression process,
A transfer end flag provided for each processor of the host device and indicating whether or not the compressed data corresponding to each partial area (hereinafter referred to as “compressed partial data”) has been transferred;
Transfer means for transmitting the compressed partial data to the printer device in the order of arrangement of the partial areas in the scan line and turning on the transfer end flag of the processor corresponding to the compressed partial data when the transfer of the compressed partial data is completed; With
The compression control means determines that new data can be processed for the processor whose transfer end flag is ON, and instructs the processor to compress the print image included in the partial area corresponding to the processor. The transfer end flag corresponding to
The printer device
A print engine for printing,
A FIFO type data reception buffer for receiving compressed partial data corresponding to each of the partial areas when at least one scan line constituting the image is divided into a plurality of partial areas from a host device ; ,
Decompression control means for assigning at least one of a plurality of processors of the printer device to compressed partial data and performing image decompression processing in parallel ;
FIFO type transfer buffer,
First transfer means for transferring from the output buffer of each processor of the printer apparatus to the transfer buffer;
Second transfer means for transferring from the transfer buffer to the print engine,
The first transfer means selects scanning lines in the order of the sub-scanning direction, selects partial areas in the order of arrangement in the scanning lines for the selected scanning lines, and outputs from the processor of the printer device corresponding to the partial areas It is determined whether or not the print image of the partial area is stored in the buffer in a decompressed state. If it is stored, the print image of the partial area is output from the output buffer of the processor corresponding to the selected partial area. Is read and stored in the transfer buffer,
The second transfer means determines whether or not data for one scanning line is stored in the transfer buffer, and if stored, reads the data for one scanning line from the transfer buffer. And transferring to the print engine .