JP2011051234A - Image processor, image forming apparatus, and image processing program - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To make processing speed in a processing means high comparing with the case not including the constitution of this present invention when performing the depicting processing of printing data by a plurality of processing means in parallel. <P>SOLUTION: A page allocating control section 35 does not carry out processing in such a way respective pages of a printing document are mechanically allocated to respective image processing modules 37 but carries out processing in such a way that the respective pages of the printing document are allocated dynamically to the respective image processing modules 37 according to the processing quantity of the pages waiting processing in the respective image processing modules 37. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  The present invention relates to an image processing apparatus, an image forming apparatus, and an image processing program.

  In an image forming apparatus such as an electrophotographic system, print data (bitmap data) is drawn from a print document and output to a printer engine to form an image.

  In the process of drawing bitmap data from a print document recorded in a page-independent page description language such as PDF (Portable Document Format), the page breaks can be easily determined from the page configuration information of the print document.

  On the other hand, in the process of drawing bitmap data from a printed document recorded in a page description language such as PostScript that is not page-independent, there is no page configuration information, so it is impossible to know which page is where it is. To do this, it is necessary to find the break between pages while parsing from the beginning of the printed document. Patent Documents 1 and 2 disclose techniques for parallel processing of drawing bitmap data from a print document recorded in a page description language that is not page-independent in an image processing apparatus having a plurality of image processing modules. Things are known.

  Patent Document 1 describes two types of methods (1. centralized processing method and 2. distributed processing method). In the centralized processing method, “empty drawing” is performed by the master, the format information and the top address of each page are found, these two types of information are sequentially passed to each slave, and each slave “actually draws” only the corresponding page. . Also shown is a case where the PDL of the corresponding page portion is cut out instead of the top address. However, in this centralized processing method, since the master generates format information up to the previous page and delivers it to the slave, the processing load on the master is heavy. Further, as the number of slaves is increased to increase the multiplicity of parallel processing, the processing load on this master increases. Therefore, the slave performance cannot be effectively utilized as the number of slaves increases.

  On the other hand, in the distributed processing method, different numbers 1, 2, 3,..., N are assigned in advance to processing units such as N processors, and “empty drawing” and “real drawing” are performed in a page cycle N. Repeat the process indefinitely. In this method, each processor generates and updates the format information by itself, so that the format information and page head position information passing processing required in the centralized processing method is not necessary, and the number of processors increases. There is a merit that the performance is improved. However, since each processor mechanically converts only page numbers having a constant cycle value into print data, if the progress of processing in each processor is different, the performance of the processing unit with the slowest processing performance of the image processing apparatus Limited by speed.

Japanese Patent No. 3553985

  An object of the present invention is to prevent the processing performance of an image processing apparatus from being restricted to the slowest processing unit among processing units that perform a plurality of drawing processes, and to concentrate the processing load on a single processing unit. Is to prevent.

  According to the first aspect of the present invention, there is provided a plurality of processing means for performing drawing processing for drawing print data from a print document for each page and performing parallel processing, and any of the plurality of processing means for processing each page. And an allocating unit that executes or allocates the allocating unit, wherein the allocating unit performs the allocation according to a processing amount of the page that is waiting for processing by each processing unit.

  According to a second aspect of the present invention, in the image processing apparatus according to the first aspect, the image processing apparatus further includes a specialization unit that performs a parsing process for the print document in a manner specific to detecting a break between pages, and the allocation unit includes: Allocation is performed as to which of the plurality of processing means is to execute the processing of the page in which the delimiter is detected by the specializing means.

  According to a third aspect of the present invention, in the image processing apparatus according to the first or second aspect, the processing means performs the parsing of the print document over all pages, and the allocation means The drawing is performed on the page on the condition that the page is allocated to be executed.

  According to a fourth aspect of the present invention, a plurality of processing means for sharing drawing of print data from a print document for each page and performing parallel processing, and processing of each page is executed by any of the plurality of processing means. Allocating means for performing or allocating, and image forming means for forming an image based on the printed document drawn by the processing means, and the allocating means is waiting for processing in the processing means. An image forming apparatus comprising: performing the allocation according to a processing amount of the page.

  According to a fifth aspect of the present invention, a plurality of processing means for sharing drawing of print data from a print document for each page and performing parallel processing, and processing of each page is executed by any of the plurality of processing means. Allocating means for performing or allocating the image to the computer, wherein the allocating means performs the allocation according to the processing amount of the page that is waiting for processing in each processing means, and the computer-readable image It is a processing program.

  According to the first, fourth, and fifth aspects of the present invention, the processing load is prevented while preventing the performance of the image processing apparatus from being restricted to the slowest processing means among the processing means for performing a plurality of drawing processes. Can be prevented from concentrating on one processing means.

  According to the second aspect of the present invention, it is possible to speed up the processing of the previous stage of the processing means as compared with the case where this configuration is not provided.

  According to the third aspect of the present invention, it is possible to speed up the processing in the processing means as compared with the case where this configuration is not provided.

1 is a block diagram of electrical connection of an image forming apparatus according to an embodiment of the present invention. FIG. 3 is a functional block diagram of processing executed by the image forming apparatus according to the embodiment of the present invention. FIG. 4 is a functional block diagram illustrating processing executed by a page configuration analysis unit and a print data generation unit in the image forming apparatus according to the embodiment of the present invention. FIG. 4 is a functional block diagram illustrating processing executed by each image processing module in the image forming apparatus according to the embodiment of the present invention. 6 is a flowchart illustrating processing executed by each image processing module in the image forming apparatus according to the embodiment of the present invention. FIG. 4 is a functional block diagram illustrating processing executed by each image processing module in the image forming apparatus according to the embodiment of the present invention. It is a block diagram explaining the outline | summary of the process which draws print data from a print document. FIG. 10 is a block diagram illustrating an example in which a process of drawing bitmap data from a print document recorded in a page-independent page description language is performed in parallel by a plurality of image processing modules. FIG. 10 is a block diagram illustrating an example in which a process of drawing bitmap data from a print document recorded in a page description language that is not page-independent is performed in parallel by a plurality of image processing modules.

  Embodiments of the present invention will be described below with reference to the drawings.

[Prerequisite technology]
In an electrophotographic image forming apparatus, print data (bitmap data) is drawn from a print document and output to a printer engine to form an image. Note that the image forming apparatus may form an image by an inkjet method.

  FIG. 7 is a block diagram illustrating an outline of processing for drawing print data from a print document.

  This process is executed by the interpreter unit 201 at the preceding stage and the renderer unit 202 that performs the process after the interpreter unit 201.

  Hereinafter, the process executed by the interpreter unit 201 may be referred to as “I” process. The interpreter unit 201 includes a pre-processing unit 203 that performs pre-processing and a post-processing unit 204 that performs post-processing.

  The pre-processing unit 203 performs syntax analysis (parser) processing of the print document and extracts various drawing information. As a result, the pre-processing unit 203 receives drawing objects (characters, graphics, images, etc.) 205, graphics state information (color space type, coordinate position, character drawing attributes, etc.) 206, page breaks (page-to-page , Etc. are output. Such parsing processing (parser) processing may be referred to as “P” processing hereinafter.

  The post-processing unit 204 develops the drawing object 205 extracted by the pre-processing unit 203 into bitmap data constituting a page as pre-processing of processing by the renderer unit 202, so that a primitive drawing element such as a rectangle or a trapezoid is used. Conversion to intermediate language (display list creation) is performed. Such an intermediate language conversion (display list creation) process may be referred to as “D” process below.

  The renderer unit 202 includes a drawing unit 208, and performs drawing (rendering) processing that draws primitive drawing elements based on the display list 209 output from the post-processing unit 204 and develops bitmap data. . Hereinafter, such drawing (rendering) processing may be referred to as “R” processing. The printer engine forms an image based on the print data 210 that is bitmap data after the drawing process.

  The process of drawing print data from a print document as described above can be performed at high speed by sharing a plurality of pages of a print document with a plurality of image processing modules and performing the processes in parallel with the plurality of image processing modules. Can be achieved.

  Also, the assignment to a plurality of image processing modules is not performed by cutting out a print document for each page and distributing each page to a plurality of image processing modules. Since this is performed in a form in which all pages are transmitted and the page to be processed is notified in the print document, in this embodiment, it is not necessary to perform such a sorting process.

  FIG. 8 is a block diagram for explaining an example in which a process of drawing bitmap data from a print document recorded in a page-independent page description language is processed in parallel by a plurality of image processing modules.

  In the process of drawing bitmap data from a print document recorded in a page-independent page description language such as PDF (Portable Document Format), the page breaks can be easily determined from the page configuration information of the print document.

  A printed document 101 recorded in a page-independent page description language such as a PDF document is a document composed of one page, two pages,..., N pages. The print document 101 includes a page configuration dictionary 102, and by referring to this, the page breaks in the print document 101 can be known. The image processing unit 103 includes a plurality of ((1) number, (2) number,..., (N) number) image processing modules 104. The plurality of image processing modules 104 perform processing for drawing bitmap data from the print document 101 in a shared manner. Since the print document 101 can easily identify the page break position, the processing of each page is assigned to each image processing module 104. That is, the (1) number image processing module 104 processes page 1, 1 + N page, 1 + 2N page,..., And (2) number image processing module 104 processes page 2, 2 + N page, 2 + 2N page,. And ... and so on.

  As described above, when the print document 101 recorded in the page-independent page description language is processed in parallel by the plurality of image processing modules 104, the bitmap data creation time of a page is determined by “I” processing and “ Only the time required for the “R” process is required, and the image processing module 104 does not need to perform any analysis on pages that are not in charge of processing by the image processing module 104 (only the image processing module 104 in charge of the processing of the page). Analysis). Therefore, the time required for processing the print document 101 by the image processing unit 103 is compared with the case where the image processing unit 103 includes only a single image processing module 104, assuming that the print document 101 has n pages in total. And 1 / N of the total time required for the “I” process and the “R” process for the n page (when the time required for the “I” process and the “R” process is the same for each page).

  FIG. 9 is a block diagram for explaining an example in which a process of drawing bitmap data from a print document recorded in a page description language that is not page-independent is performed in parallel by a plurality of image processing modules.

  In contrast to the page-independent page description language described above, in the process of drawing bitmap data from a printed document recorded in a non-page-independent page description language such as PostScript, there is no page configuration information, so which page It is not known where it is, and in order to know this, it is necessary to find the break between pages while parsing from the beginning of the printed document.

  That is, a print document 151 recorded in a page-independent page description language such as PostScript is a document composed of one page, two pages,..., N pages. Since the print document 151 does not include a page configuration dictionary, it is not known which page is in the data of the print document 151. Therefore, it is necessary to analyze the print document 151 from the top and find a page break.

  The image processing unit 153 includes a plurality of ((1) number, (2) number,..., (N) number) image processing modules 154. The plurality of image processing modules 154 perform processing for drawing bitmap data from the print document 151 in a shared manner. The sharing of processing for each page is assigned to each image processing module 154. That is, the (1) number image processing module 154 processes page 1, 1 + N page, 1 + 2N page,..., And (2) number image processing module 154 processes page 2, 2 + N page, 2 + 2N page,. And ... and so on.

  However, in this print document 151, the page break position is not easily known, and therefore, each image processing module 154 needs to find the top position of the page to be printed while performing syntax interpretation of the print document 151.

  Therefore, each image processing module 154 requires “I” processing for all pages. This is because each image processing module 154 reveals the page breaks and knows the position of the page that it is responsible for.

  However, since the “R” process only needs to be performed for the page to be handled by the image processing module 154, only the “R” process indicated by hatching in FIG. 9 is executed, and the “R” process not indicated by hatching is performed. It is not necessary to carry out processing.

  As described above, even when the print document 151 recorded in a page description language that is not page-independent is processed in parallel by the plurality of image processing modules 154, unnecessary “R” processing can be omitted. The processing speed can be increased by parallel processing by the processing module 154.

  However, even if only the target page is converted to bitmap data, the page description language commands are set up to immediately before, and the various format information to be transferred to the next page is updated and stored each time. The point that needs to be set as the initial value of the page is a unique restriction when processing a printed document recorded in a page description language that is not page-independent.

[Contents of embodiments for carrying out the invention]
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a block diagram of electrical connection of the image forming apparatus according to the present embodiment.

  The image forming apparatus 1 is connected to the host computer 3 via the LAN 2, processes a print request transmitted from the host computer 3, and forms an image on a medium such as paper.

  The image forming apparatus 1 includes an MPU module 11 and a plurality (N) of SPU modules 12 (number (1), number (2),..., Number (N)). These modules implement the image processing apparatus of the present invention.

  The MPU module 11 and the N SPU modules 12 are connected to a communication control unit 14, a secondary storage device 15, a printer engine 17 and a shared memory 18 (via an engine control unit 16) via a system bus 13. ing.

  The MPU module 11 is a master module that controls image forming processing in the image forming apparatus 1. The SPU module 12 is a slave processor module that performs processing for converting a print document included in a print request transmitted from the host computer 3 into print data (bitmap data).

  Each of the MPU module 11 and each SPU module 12 performs various calculations and serves as a work area for the CPU 21 that centrally controls each part, a ROM 23 that stores programs executed by the CPU 21 such as an image processing program 22, and the like. A RAM 24 is connected via a local bus 25. The local bus 25 is connected to the system bus 13 via a bus I / F (interface) 26.

  The image processing program 22 may be set up from the beginning of manufacture of the image forming apparatus 1. However, the image processing program 22 is read later from a storage medium storing the image processing program 22 by a storage medium reader, and the secondary storage device 15 or the like. Or may be downloaded from the Internet or the like and set up in a storage device such as the secondary storage device 15.

  The communication control unit 14 controls communication with the LAN 2 of the image forming apparatus 1.

  The secondary storage device 15 stores data such as a print request transmitted from the host computer 3.

  The shared memory 18 stores data such as bitmap data converted from a print document by the SPU module 12.

  The printer engine 17 operates under the control of the engine control unit 16 and forms an image on a print medium such as paper based on bitmap data converted from a print document. As an image forming means, various means such as an electrophotographic system and an ink jet system can be used.

  FIG. 2 is a functional block diagram of processing executed by the image forming apparatus 1.

  The print document receiving unit 31 receives a print document to be processed from the host computer 3, and this print document is stored in a print document storage unit 32 prepared in the secondary storage device 15.

  The system control unit 33 is realized by the MPU module 11. When the print document reception unit 31 receives a print document, the system control unit 33 controls each unit to process the print document.

  The page configuration analysis unit 34 is realized by the MPU module 11 and sequentially analyzes from the beginning to the end of the printed document, and notifies the page allocation control unit 35 of the notification that the break between pages has been detected or the corresponding page number to be detected. .

  The print data generation unit 36 converts the print document into bitmap data. The print data generation unit 36 includes a plurality (N) of image processing modules 37 (number (1), number (2),..., Number (n)). Each image processing module 36 is realized by each SPU module 12. That is, the (1) number image processing module 36 is realized by the (1) number SPU module 12, the (2) number image processing module 36 is realized by the (2) number SPU module 12,. No. image processing module 36 is realized by the (n) No. SPU module 12. The N image processing modules 37 share the processing of each page of the print document, and process the print documents in parallel with each other.

  The page allocation control unit 35 determines which page is to be processed by which image processing module 36 based on the notification from the page configuration analysis unit 34 in the printed document, and allocates the processing of the page.

  The print page management unit 38 manages the bit map data generated by the print data generation unit 36 while sorting the page order, and supplies the page order to the engine control unit 16.

  FIG. 3 is a functional block diagram for explaining processing executed by the page configuration analysis unit 34 and the print data generation unit 36.

  First, the processing in the page configuration analysis unit 34, which is the pre-processing of the image processing module 37, is speeded up, and even if the number of image processing modules 37 is large, the image processing modules 37 are successively received without waiting for the image processing modules 37. A means for enabling the processing of the pages to be allocated will be described.

  The page configuration analysis unit 34 sequentially analyzes from the beginning to the end of the printed document, and each time a page break is detected, a notification that a page break is detected (page detection notification) or a corresponding page to be detected. The number is notified to the page allocation control unit 35. The page configuration analysis unit 34 specializes in processing for detecting such page breaks, and does not perform processing such as detecting format information of a printed document. Therefore, as compared with the case where the page configuration analysis unit 34 performs detection of the print document format information and the like, the processing load of the page configuration analysis unit 34 which is the preprocessing of the image processing module 37 is small.

  That is, the processing performed by the page configuration analysis unit 34 is “P” processing, but the page break 207 described above with reference to FIG. 7 is extracted from the print document 41, but the drawing object 205 and graphics state information 206 are extracted. Do not do. Therefore, in the syntax analysis processing described above with reference to FIG. 7, the processing performed by the page configuration analysis unit 34 is limited to the extraction of the page break 207.

  Next, means for speeding up the processing in the print data generation unit 36 will be described.

  That is, the processing load on the image processing module 37 is not uniform for each page. Some pages are heavily loaded and others are small. If there is a difference in processing load between the image processing modules 37, the time required for processing by the print data generation unit 36 is constrained by the processing time of the largest processing load among the plurality of image processing modules 37. .

  Therefore, the page assignment control unit 35 does not mechanically perform the process of assigning each page of the print document to each image processing module 37, but according to the processing amount of the page waiting for processing in each image processing module 37. Thus, each page of the print document is dynamically allocated to each image processing module 37.

  Specifically, the page allocation control unit 35 assigns the processing of pages 1, 1a, 1b,... To the (1) number image processing module 37, and 2, 2a, 2b to the (2) number image processing module 37. ,... Page processing is allocated, and processing of each page of the printed document is allocated, and the page number information of the pages that have been allocated to each image processing module 37 but have not yet been processed. Each queue 51 is held in each image processing module 37. Therefore, referring to this page queue 51, the image processing module 37 with the smallest number of pages held as the page queue 51 is the image processing module with the least amount of processing for the pages waiting to be processed. It is sufficient to estimate that the number is 37 and to allocate a new page process to the image processing module 37.

  FIG. 4 is a functional block diagram for explaining processing executed by each image processing module 37. FIG. 5 is a flowchart for describing processing executed by each image processing module 37.

  In FIG. 4, the processing of each page from the first page of the print document 41 is shown in a horizontal row from left to right. When the page assignment control unit 35 assigns each page of the print document 41 to each image processing module 37, the page assignment control unit 35 gives the page numbers of the assigned pages to the individual image processing modules 37 in ascending order.

  Each image processing module 37 sets the initial value of “current page number” to 0 (step S1), and waits for a page to be processed to be assigned from the page assignment control unit 35 (step S2). If there is this assignment (Y in step S2), if the assigned page number is larger than “current page number” (Y in step S3), only “P” processing is performed for the page with the current page number ( Step S4), “D” processing and “R” processing are not performed. Then, “current page number” is counted up by +1 (step S5).

  If the assigned page number is the same as the “current page number” (N in step S3), the “P” process, the “D” process, and the page of the current page number (= assigned page number), and “R” processing is performed (step S 6), and the generated bitmap data is output to the print page management unit 38. Then, “current page number” is counted up by +1 (step S5). The “D” process and the “R” process are combined to form a broad drawing process.

  In this way, each image processing module 37 performs only “P” processing on pages that should not be processed by itself, and does not perform “D” processing and “R” processing. That is, the “P” process is executed over the entire print document 41 to determine which part of the print document is the data of the page to be processed by itself, but the data determined not to be the page to be processed by itself. “D” processing and “R” processing are omitted.

  In this case, the “P” process is performed even on a page that is not a page to be processed by itself. In this case, the page break 207 is extracted from the processes described with reference to FIG. However, the drawing object 205 is discarded. Also, the graphics state information 206 is stored internally as information that is inherited between pages.

  FIG. 6 is a functional block diagram illustrating processing executed by each image processing module 37.

  In FIG. 6, the processing of each page from the first page of the print document 41 for each image processing module 37 is shown in a horizontal row from left to right.

  When N pages of the print document 41 are processed by the single image processing module 37, “(time required for“ P ”processing + time required for“ D ”processing + time required for“ R ”processing) × N” ”” Time is required for processing.

  On the other hand, when N pages of the print document 41 are processed in parallel by the N image processing modules 37, assuming that the number of pages processed by each image processing module 37 is equal, “(“ P ”processing” The time required for the processing is as follows: time required + time required for “D” processing + time required for “R” processing + time required for “P” processing × (N−1) ”.

  Therefore, the processing time of “(time required for“ D ”processing + time required for“ R ”processing) × (N−1)” ”is reduced as compared with the case where parallel processing is not performed.

  In this case, the time required for processing by the page configuration analysis unit 34 is “time required for“ P ”processing × N”. Therefore, the time required for the page configuration analysis unit 34 to analyze the entire print document 41. Is shorter than the time required for the image processing module 37 by “time required for“ D ”processing + time required for“ R ”processing” ”.

DESCRIPTION OF SYMBOLS 1 Image forming apparatus 17 Printer engine 34 Page structure analysis part 35 Page allocation control part 36 Print data generation part 37 Image processing module

Claims (5)

A plurality of processing means for performing parallel processing by sharing drawing processing for drawing print data from a print document for each page;
Allocating means for allocating which of the plurality of processing means is to execute the processing of each page;
With
The allocation unit performs the allocation according to the processing amount of the page that is waiting for processing in each processing unit.
Image processing device. Further comprising specialized means for specially performing parsing processing of the printed document for detecting a break between pages;
The allocating means allocates which one of the plurality of processing means is to execute the processing of the page whose delimiter is detected by the specializing means.
The image processing apparatus according to claim 1.   Each of the processing means performs the parsing of the printed document over all pages, and performs the drawing on the page on the condition that the page is allocated by the allocating means as one to be executed by itself. The image processing apparatus according to claim 1. A plurality of processing means for sharing the drawing of the print data from the print document for each page and processing in parallel;
Allocating means for allocating which of the plurality of processing means is to execute the processing of each page;
Image forming means for forming an image based on the printed document after drawing by the processing means;
With
The allocation unit performs the allocation according to the processing amount of the page that is waiting for processing in each processing unit.
An image forming apparatus. A plurality of processing means for sharing the drawing of the print data from the print document for each page and processing in parallel;
Allocating means for allocating which of the plurality of processing means is to execute the processing of each page;
To the computer,
The allocation unit performs the allocation according to the processing amount of the page that is waiting for processing in each processing unit.
An image processing program readable by a computer.

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