JP2015001882A - Print image processing system and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a generation speed of print image data higher than in the case where a ratio between the number of means for translating a logic page and the number of means for translating an element of a cache object of a form, or the like is fixed.SOLUTION: A system includes, for example, two logic page translation parts and one dual-purpose translation part. The dual-purpose translation part can be changed over as to whether to be functioned as a logic page translation part or to be functioned as a form translation part. In the case that a progress level of form translation progresses more greatly than a progress level of logic page translation (a determination result of S1004 is Y), means for controlling the changeover sets the dual-purpose translation part to the logic page translation part (S1006). On the other hand, in the case that the progress level of the form translation is likely to be caught up with the progress level of the logic page translation (a determination result of S1012 is Y), the means sets the dual-purpose translation part to the logic page translation part (S1014).

Description

  The present invention relates to a print image processing system and a program.

  In general, print document data sent from a personal computer to a printing apparatus is called a page description language (hereinafter referred to as PDL) such as PostScript (registered trademark) or PDF (Portable Data Format: ISO 32000-1). Abbreviation). In a printing apparatus, print document data is converted into image data in a bitmap format (also called a raster format) by a data processing device called RIP (Raster Image Processor), and the image data is printed by a print engine. In addition to the method of directly converting PDL data to a raster image, PDL data is converted into intermediate language format data such as a display list having a smaller granularity than the PDL command and buffered. A printing apparatus that performs a two-stage conversion of a bitmap format is also well known.

  2. Description of the Related Art Conventionally, there is also known a system in which conversion from PDL data to image data in a bitmap format or an intermediate language format is executed in parallel by a plurality of data processing devices for each predetermined unit such as a page unit.

  Conventionally, when a data processing apparatus converts a document element (object) described in PDL in print data into a bitmap format or an intermediate language format, the conversion result data corresponds to the document element identification information. If the same document element needs to be converted later by the same or different data processing device, the conversion process may be omitted by using the cached data. ing.

  Patent Document 1 discloses a mechanism for converting print data in a page description language into image data such as a bitmap that can be handled by a printing apparatus, an intermediate data generation unit that converts PDL into intermediate data, and intermediate data as an image. A system is disclosed in which a plurality of intermediate data generation units and a plurality of drawing data generation units are operated in parallel, divided into two stages of a drawing data generation unit that converts data. In the description related to FIGS. 13 to 20 of Patent Document 1, an example of handling a form that is repeatedly used on a plurality of pages is shown. In the description, it is shown that the intermediate data or image data of the form is stored in the cache memory in the drawing data generation unit, and the form data extracted from the cache memory is used when generating the image data of the page including the form. Has been.

  In the print document conversion apparatus disclosed in Patent Document 2, the RIP module control unit activates the RIP module as one process. The RIP module internally runs a plurality of page conversion processing threads, and RIP processes a plurality of pages in parallel by each thread. The page allocation unit allocates different pages of the print document data to each page conversion processing thread. Multiple page conversion processing threads use the shared cache in the same memory space, so that the conversion results of other page conversion processing threads in the shared cache (e.g., form image data) can be used without inter-process communication. Etc.).

  In the printing system disclosed in Patent Document 3, a device for converting PDL print data into raster image data is divided into two-stage devices, a front-end device at the front stage and a back-end device at the rear stage. Yes. The front stage has a parallel configuration with a plurality of front-end devices, and the rear stage has a parallel configuration with a plurality of processing circuits mounted in one back-end device. A plurality of processing circuits in the back-end device share a cache memory in the back-end device. In the cache memory, data of an object that is commonly used in a plurality of pages, such as a form, is cached.

JP 2011-070337 A JP 2011-230470 A JP 2012-200955 A

  An object of the present invention is to increase the generation speed of print image data as compared with a case where the ratio of the number of means for interpreting logical pages and the number of means for interpreting elements to be cached such as forms is fixed.

  The invention according to claim 1 interprets the logical page in the print data and outputs the interpretation result, and interprets the cache target element included in each logical page in the print data. One or more dual-use interpreting means capable of functioning as cache interpreting means for storing the cache means in the cache means, and whether each of the dual-use interpreting means functions as the logical page interpreting means or the cache interpreting means. A print image of each logical page by using the switching means for switching between, the interpretation result of each logical page output from each logical page interpretation means, and the interpretation result of the cache target element stored in the cache means Print image data generation means for generating data and supplying the generated print image data to a printing apparatus. When the cache interpreting unit finds a cache target element whose interpretation result is not stored in the cache unit from the print data, it interprets the found cache target element, and interprets the interpretation result according to a predetermined generation rule. The logical page interpretation unit interprets the cache target element for each cache target element included in the logical page to be processed in association with the cache identification information generated from the data of the cache target element. Instead, the cache reference command including the cache identification information generated according to the generation rule is generated from the data of the cache target element, and the generated cache reference command is converted into the interpretation result of the logical page as the interpretation result of the cache target element. Built-in, When the print image data generating means generates the print image data from the interpretation result of each logical page output from each logical page interpreting means and finds the cache reference command from the interpretation result of the logical page, the cache reference An interpretation result corresponding to the cache identification information included in the command is acquired from the cache unit, and print image data of a cache target element corresponding to the cache identification information is generated using the acquired interpretation result, and the logic The switching unit is combined with the print image data of the page, and the switching unit interprets the progress of the interpretation of the cache target element in the print data by the cache interpretation unit, and interprets the logical page in the print data by the logical page interpretation unit. One or more dual-use interpreting means based on the difference between the degree of progress and The print image processing system is characterized in that the ratio between the one that functions as the cache interpretation means and the one that functions as the logical page interpretation means is controlled.

  According to a second aspect of the present invention, the switching unit includes a progress degree of interpretation of the cache target element in the print data by the cache interpretation unit, and interpretation of a logical page in the print data by the logical page interpretation unit. The ratio of the one functioning as the cache interpreting means to the function functioning as the logical page interpreting means among the one or more dual interpreting means is controlled so that the difference between the degree of progress and the difference is within a predetermined range. The print image processing system according to claim 1.

  According to a third aspect of the present invention, the switching unit determines whether the logical page interpretation unit interprets the logical page in the print data based on the progress of interpretation of the cache target element in the print data by the cache interpretation unit. 3. The ratio of the one or more dual-purpose interpreting units that function as the cache interpreting unit is reduced as the leading degree obtained by subtracting the progress degree is increased. 3. A print image processing system.

  According to a fourth aspect of the present invention, the switching unit determines whether the logical page interpretation unit interprets a logical page in the print data based on a progress degree of interpretation of the cache target element in the print data by the cache interpretation unit. 4. The ratio of the one or more dual-use interpreting means that functions as the cache interpreting means is increased as the leading degree obtained by subtracting the progress degree is smaller. The print image processing system according to item 1.

  The invention according to claim 5 interprets a logical page interpreting means for interpreting a logical page in print data and outputting an interpretation result, and a cache target element included in each logical page in the print data. One or more dual-use interpretation means capable of functioning as cache interpretation means for storing the interpretation result in the cache means, and the dual-use interpretation means function as either the logical page interpretation means or the cache interpretation means. Switching means for switching between the logical page, the interpretation result of each logical page output from each logical page interpretation means, and the interpretation result of the cache target element stored in the cache means, printing each logical page As print image data generation means for generating image data and supplying the generated print image data to a printing apparatus When the cache interpreting unit finds a cache target element in which the interpretation result is not stored in the cache unit from the print data, the cache interpreting unit interprets the found cache target element, and the interpretation result Are stored in the cache means in association with the cache identification information generated from the data of the cache target element in accordance with a predetermined generation rule, and the logical page interpreting means respectively stores the cache included in the logical page to be processed. For the target element, instead of interpreting the cache target element, a cache reference command including the cache identification information generated according to the generation rule is generated from the data of the cache target element, and the generated cache reference command is stored in the cache target element. Interpretation Embedded in the interpretation result of the logical page, and the print image data generation means generates the print image data from the interpretation result of each logical page output by each logical page interpretation means. When a cache reference command is found, an interpretation result corresponding to the cache identification information included in the cache reference command is acquired from the cache unit, and a cache target element corresponding to the cache identification information is acquired using the acquired interpretation result The print image data of the logical page is synthesized and combined with the print image data of the logical page, and the switching means includes a progress degree of interpretation of the cache target element in the print data by the cache interpretation means, and the logical page interpretation means. Progress of interpretation of logical pages in the print data by And controlling the ratio of the one or more dual-use interpreting means that functions as the cache interpreting means to the logical page interpreting means. .

  According to the first or fifth aspect of the invention, it is possible to increase the print image data generation speed as compared with the case where the ratio of the number of logical page interpretation means and cache interpretation means is fixed.

  According to the second aspect of the present invention, the generation speed of the print image data can be increased as compared with the case where one of the interpretation of the logical page and the interpretation of the cache target element is allowed to precede significantly the other.

  According to the third aspect of the invention, it is possible to prevent the interpretation of the cache target element from proceeding too much than the interpretation of the logical page.

  According to the invention of claim 4, it is possible to prevent the interpretation of the logical page from proceeding too much than the interpretation of the cache target element.

It is a block diagram which shows the example of a structure of an image processing system. FIG. 3 is a block diagram illustrating an example of an internal configuration of a print controller. FIG. 3 is a block diagram illustrating an example of an internal configuration of a print controller according to an embodiment. It is a figure which shows the example of the whole process sequence of a logical page interpretation part and a form interpretation part. It is a figure which shows the example of the process sequence for every command of a logical page interpretation part. It is a figure which shows the example of the process sequence for every command of a form interpretation part. It is a figure which shows the example of the whole process sequence of a drawing part. It is a figure which shows the example of the procedure of the drawing process for every command of a drawing part. It is a figure which shows an example of the procedure of control of the ratio of a logical page interpretation part and a form interpretation part. FIG. 10 is a diagram illustrating an example of a progress of processing of each logical page interpretation unit and a dual-use interpretation unit at an initial stage of a print job. It is a figure which shows the modification of the procedure of control of the ratio of a logical page interpretation part and a form interpretation part. It is a figure which shows the 2nd modification of the procedure of the control of the ratio of a logical page interpretation part and a form interpretation part.

<System hardware configuration>
FIG. 1 is a block diagram illustrating an example of the configuration of an image processing system. Each of the image processing systems according to various embodiments of the present invention described below is assumed to have the configuration illustrated in FIG. The system in the example of FIG. 1 includes a terminal device 10, a print controller 20, and a printing device 50. The print controller 20 includes a front end device 30 and a back end device 40. The terminal device 10 is connected to the front-end device 30 via the communication unit 60 and transmits a print job including a document print command to the front-end device 30 in accordance with a user instruction. The front-end device 30 is connected to the back-end device 40 via the communication unit 62, and the back-end device 40 is connected to the printing device 50 via the communication unit 64.

  The communication means 60, 62, 64 may be a network such as a LAN (Local Area Network). The communication means 60, 62, and 64 may be communication means common to each other or may be different communication means. For example, a LAN is used as the communication means 60 between the terminal device 10 and the front-end device 30, and the communication means 62 between the front-end device 30 and the back-end device 40 and between the back-end device 40 and the printing device 50. As the communication means 64, dedicated communication means different from the LAN may be used.

  In the system of the example of FIG. 1, the print job transmitted from the terminal device 10 is processed in the front-end device 30, and the processing result data is passed to the back-end device 40, and the drawing data generated in the back-end device 40. Printing by the printing apparatus 50 is performed according to (also referred to as raster data).

  The terminal device 10, the front-end device 30, and the back-end device 40 in the example of FIG. 1 can be realized by a general-purpose computer, for example. The computer has a circuit configuration in which a CPU (central processing unit), a memory (primary storage), various I / O (input / output) interfaces, a communication interface, and the like are connected via a bus as hardware. The computer exchanges data with other devices via the communication interface. Also, an input device such as a keyboard and a mouse, and a display device such as a CRT (Cathode Ray Tube) and a liquid crystal display are connected to the bus via, for example, an I / O interface. In addition, a disk drive for reading portable non-volatile recording media of various standards such as HDD (hard disk drive), CD, DVD, and flash memory is connected to the bus via an I / O interface. Such a drive functions as an external storage device for the memory. A program in which the processing content of each embodiment described later is described is stored in a fixed storage device such as an HDD via a recording medium such as a CD or DVD or via a network, and is installed in a computer. The programs stored in the fixed storage device are read into the memory and executed by the CPU, whereby the processing of each embodiment and modification described later is realized.

  In each of the embodiments and modifications described below, some of the functions of the back-end device 40 may be realized by hardware processing, not software processing by executing a program. The hardware processing may be performed using, for example, a processor called Dynamic Reconfigurable Processor (DRP) that can dynamically reconfigure a circuit in the middle of execution of processing. Alternatively, the hardware processing may be performed using a circuit such as ASIC (Application Specific Integrated Circuit). For example, hardware elements such as DRP and ASIC that execute a part of the functions of the back-end device 40 are configured in advance, and such hardware elements are connected to a general-purpose computer bus so that The end device 40 may be realized.

  As a specific example of hardware for realizing the front-end device 30 and the back-end device 40, it is conceivable to use a blade server in which a plurality of information processing devices each functioning as a server are mounted in a single casing. The blade server is a server device in which a general-purpose computer including a CPU and a memory is mounted on a single board (blade) and a plurality of blades are mounted in a housing. For example, one blade mounted on the blade server may function as the front end device 30 and the other one blade may function as the back end device 40. Alternatively, for example, each of the front-end device 30 and the back-end device 40 may be realized by a plurality of blades mounted on a blade server.

  The printing device 50 is a device that performs printing on a medium such as paper, and may be, for example, a continuous paper printer. Hereinafter, an example of each embodiment will be described by taking a case where a continuous paper printer is used as the printing apparatus 50 as an example. Note that the printing apparatus 50 performs printing using an electrophotographic, inkjet, or other printing engine.

<Embodiment>
FIG. 2 shows an example of functional configurations of the front-end device 30 and the back-end device 40 included in the print controller 20. The front-end device 30 includes a print job reception unit 32, a page distribution unit 34, and a plurality of interpretation units 36. The back end device 40 includes an intermediate data buffer 42, a drawing unit 44, and an output buffer 46.

  The print job receiving unit 32 of the front end device 30 receives a print job from the terminal device 10. In the example of this embodiment, the print job includes a command for printing a document and data describing a document to be printed in a page description language. A page description language (abbreviated as PDL: PDL is an abbreviation of Page Description Language) is a computer programming language for causing an information processing device to execute display display processing, printing processing, and the like. Examples of the page description language include PostScript (registered trademark) and PDF (Portable Document Format). The data described in the page description language includes position information, format information, color information, and the like of objects such as characters and figures, images (bitmap images) constituting a document to be printed. In the following description, data in which a document to be printed is described in a page description language is referred to as “PDL data”. The print job receiving unit 32 passes the PDL data included in the received print job to the page distribution unit 34.

  The page distribution unit 34 determines which page of the pages included in the PDL data acquired from the print job reception unit 32 is to be processed by which interpretation unit 36. The “page” here is a page defined in the PDL data, that is, a logical page. One or more logical pages are printed on one side of the sheet, that is, one physical page, depending on the print setting. In the following, as apparent from the context, the term “page” refers to a logical page unless otherwise specified.

  The page distribution unit 34 assigns a page to each interpretation unit 36 based on the operating state of each interpretation unit 36. For example, the interpreter 36 that is not executing a process or the interpreter 36 that is executing a process having a lower load than the other interpreters 36 is given priority, and assigned pages are assigned in order from the first page in the PDL. The page distribution unit 34 notifies each interpreting unit 36 of the assigned assigned page and passes the PDL data acquired from the print job receiving unit 32. In this example, it is assumed that not only the portion of the assigned page in the PDL data but also the entire PDL data is passed to each interpretation unit 36. This is an example in which, for example, a page-independent PDL (that is, a type of PDL in which generation of an image of a page depends on an interpretation result of PDL data before the page) is used. As another example, when using page-independent PDL (PDL of a type that can correctly generate an image of the page with only PDL data for each page), the page distribution unit 34 sends the PDL data to each interpretation unit 36. An assignment for each page may be performed, and PDL data divided for each page may be transferred to each interpreter 36 in charge based on the assignment.

  The interpretation unit 36 interprets the PDL data acquired from the page distribution unit 34, and generates and outputs intermediate data including a command representing a drawing data generation procedure for the assigned page notified from the page distribution unit 34.

  More specifically, the interpretation unit 36 interprets the PDL data and generates intermediate data for its own assigned page. The intermediate data is data at the previous stage that is converted into data that is finally output to the printing apparatus 50. Examples of the intermediate data include a display list and a section data format (for example, see Japanese Patent Application Laid-Open No. 2011-150535 by the present applicant). Here, the interpretation unit 36 has four basic colors (for example, yellow (Y, Yellow), magenta (M, Magenta), cyan (C, Cyan), and black (K, Black) used in printing by the printing apparatus 50. ), The separated intermediate data may be generated. However, this is only an example.

  The intermediate data includes, for each object that is a component of the document to be printed, a drawing command that represents a procedure for drawing the object in the print image of the document. As a language for describing the drawing command, a language that expresses more detailed procedures than the page description language is used. For example, in the page description language, when information representing the position, shape, and size of an object on the print image is defined, the drawing command for the object in the intermediate data indicates the object in units of scanning lines in the print image. It may describe a drawing procedure. In accordance with the intermediate data, drawing data to be output to the printing device 50 is generated in the back-end device 40 described later.

  Examples of commands used in the section data format (also referred to as “run list” format) are shown below.

(1) line, ym, xl, xr, c
Draw with gradation c from x-coordinate xl to xr-1 on the scanning line of y-coordinate ym (2) duplicate
Draw in the same mode (x coordinate, gradation) as the scan line drawn immediately before (3) window, xl, xr
Draw from x coordinate xl to xr -1 with the same gradation as the scan line drawn immediately before

  The intermediate data of a certain page is regarded as a set of instructions representing the drawing procedure of each object constituting the page. The amount of intermediate data representing one page is small compared to raster data including the value of each pixel constituting the page.

  The section data format is merely an example of the intermediate data format. This embodiment can be applied to any intermediate data format. When drawing data is generated by hardware processing in the back-end device, the format of the intermediate data may be a format representing a drawing procedure that enables generation of drawing data by hardware processing, and is exemplified above. A format different from the section data format may be used.

  The intermediate data generated by the interpretation unit 36 is output to the back-end device 40. The output intermediate data is written into the intermediate data buffer 42 of the back-end device 40. The drawing unit 44 reads the intermediate data of each page stored in the intermediate data buffer 42 and generates drawing data (raster data) according to the read intermediate data of the page. The generated drawing data of each page is stored in the output buffer 46 and sequentially read out from the printing apparatus 50. The printing apparatus 50 prints the drawing data of each page read from the output buffer 46 on paper.

  Next, the configuration of the print controller 20 of the embodiment will be described with reference to FIG.

  In one example, the plurality of interpretation units 36 include a logical page interpretation unit 36-p (two logical page interpretation units 36-p1 and 36-p2 are illustrated in FIG. 3) and a form interpretation unit 36-f, respectively. Can function. However, one interpreter 36 does not function as both the logical page interpreter 36-p and the form interpreter 36-f at the same time. That is, one interpreter 36 functions as one of the logical page interpreter 36-p and the form interpreter 36-f at one time point.

  The logical page interpretation unit 36-p executes intermediate data generation for a page (logical page). The form interpretation unit 36f executes intermediate data generation for an object such as a form or an image that can be shared by a plurality of pages (that is, a result of interpretation once can be reused in a later page). Hereinafter, objects that can be shared by a plurality of pages are collectively referred to as a form. Although an object corresponding to the form and an object not corresponding to the form may be included in the page, the form interpretation unit 36-f processes only the object corresponding to the form in the page. On the other hand, the logical page interpretation unit 36-p basically processes all objects included in the page (however, the form performs special processing described later). The number of logical page interpretation units 36-p and the number of form interpretation units 36-p at a single point in time are equal to the total number of interpretation units 36 included in the front-end device 30.

  In this embodiment, the PDL data is sequentially processed from the first page, and the composition ratio between the logical page interpretation unit 36-p and the form interpretation unit 36-f operating in the front-end device 30 is dynamically controlled. To do.

  In other words, the load of PDL data interpretation processing generally varies from page to page depending on the number and complexity of objects included in the page, and how much time is spent interpreting logical pages and forms within a logical page. It will be difficult to predict whether it will take. For this reason, it is difficult to know in advance the optimal ratio of the number of logical page interpretation units 36-p and form interpretation units 36-f in the front-end device 30. Even if there is such an optimal ratio, the optimal ratio changes during the progress of interpretation of one entire print job. Therefore, in this embodiment, the configuration ratio between the logical page interpretation unit 36-p and the form interpretation unit 36-f is dynamically controlled.

  This dynamic control of the composition ratio is performed based on a comparison between the progress status of logical page interpretation (intermediate data generation) and the progress status of form interpretation. The ratio of the number of logical page interpretation units 36-p (or form interpretation units 36-f) to the total number of interpretation units 36 included in the front-end device 30 is controlled within a range of, for example, 0% to 100%.

  Note that the possible range of the ratio of the number of logical page interpretation units 36-p in the total number of interpretation units 36 in this ratio control is 0% to 100% exemplified above (that is, all interpretation units 36 are interpreted as forms). It is not limited to the case where the unit 36-f is used to the case where all the interpreting units 36 are set as the logical page interpreting unit 36-p). Instead, for example, a lower limit (or upper limit) is set for the number of logical page interpretation units 36-p, and the number of logical page interpretation units 36-p is within a range from the lower limit number to the total number of interpretation units 36. You may control the ratio which occupies.

  In the above example, all the interpretation units 36 are “bilateral” interpretation units that can function as the logical page interpretation unit 36-p and the form interpretation unit 36-f, but this is only an example. As another example, a configuration in which only a part of the interpretation units 36 among the plurality of interpretation units 36 is such a “dual use” interpretation unit and the rest are interpretation units dedicated to interpretation of logical pages is also conceivable. That is, in this configuration, the total number of interpretation units dedicated to interpretation of logical pages is the lower limit number of logical page interpretation units 36-p in the ratio control. In this example, of the total number of “double-use” interpretation units, the ratio of what functions as the logical page interpretation unit 36-p and what functions as the form interpretation unit 36-f is controlled.

  In the control of the ratio between the logical page interpretation unit 36-p and the form interpretation unit 36-f, the progress of the page interpretation progress relative to the progress of the form interpretation increases (or the progress of the form interpretation relative to the page interpretation decreases). The ratio of the logical page interpretation unit 36-p is lowered, and the ratio of the form interpretation unit 36-f is increased. On the contrary, the smaller the progress of the page interpretation with respect to the form interpretation (or the greater the advance of the form interpretation with respect to the page interpretation), the higher the ratio of the logical page interpretation unit 36-p and the lower the ratio of the form interpretation unit 36-f. .

  In this example, this ratio control is performed by the page distribution unit 34 that assigns logical pages or the like to the interpretation units 36. However, this is only an example, and a control unit that performs this ratio control may be provided separately from the page distribution unit 34.

  This ratio control will be described in more detail later.

  FIG. 3 shows that when the front-end device 30 has three interpretation units 36, two of them function as logical page interpretation units 36-p1 and 36-p2, and one as a form interpretation unit 36-f. Indicates a functioning situation.

  As described above, the form is an image that is supposed to be repeatedly used on a plurality of pages. A form is composed of one or more objects. In general, in PDL data, identification information for uniquely identifying the form in the PDL data (referred to as “form ID”) is assigned to the form. When there are commands specifying the same form ID in the PDL data, the commands represent images using the same form.

  In this embodiment, by providing a framework (form cache 48) in which intermediate data of a form once generated is cached and reused, inefficiency that intermediate data of the same form is generated many times is avoided. The form cache 48 is a cache that temporarily stores intermediate data of a form to be cached.

  Each logical page interpretation unit 36-p1 and 36-p2 generates intermediate data of the PDL data of the page allocated from the page distribution unit 34, respectively. Here, in one example, each logical page interpretation unit 36-p processes an object group other than the form in the allocated page. The form included in the page replaces the PDL command (object) group constituting the form converted into the intermediate data format, and the identification information indicating the intermediate data of the form cached in the form cache 48 ( This is replaced with an intermediate data command that refers to “cache ID”. The intermediate data of each page generated by each logical page interpretation unit 36 -p is sent to the intermediate data buffer 42 of the back-end device 40.

  On the other hand, the form interpretation unit 36-f interprets the PDL command group of the form in the PDL data, and generates intermediate data representing the form. Then, the generated intermediate data of the form is registered in the form cache 48 of the back-end device 40. Here, the form interpreter 36-f assigns at least a unique cache ID in the print job to the intermediate data representing the form to be registered in the form cache 48, and associates the cache ID with the cache ID. The intermediate data is registered in the form cache 48.

  The logical page interpretation unit 36-p processes only the allocated pages (that is, interpretation and generation of intermediate data) of the PDL data of the print job, whereas the form interpretation unit 36-f performs the PDL of the print job. Process all pages of data. However, the form interpreter 36-f processes only the form in the page, and does not process general objects not included in the form.

  The logical page interpretation units 36-p1 and 36-p2 and the form interpretation unit 36-f are typically realized as processes executed on the CPU. For example, in a system configuration using a multi-core CPU, a configuration in which the processes of the interpretation unit 36 are executed one by one in each core can be considered.

  The cache management unit 38 holds management information of cache data (that is, intermediate data of the form) held in the form cache 48. For each cache data, the cache management unit 38 has a cache ID and information indicating the storage location of the cache data in the storage space of the form cache 48 (for example, a combination of the start address and the size of the data). Remembered. When processing the form in the PDL data, the form interpretation unit 36-f asks the cache management unit 38 whether or not the cache data of the form is registered in the form cache 48. Cache data is not generated, and cache data is generated only when it is not registered.

  The drawing unit 44 of the back-end device 40 reads the intermediate data of each page in the intermediate data buffer 42, for example, in page order, and generates drawing data according to the command of the read intermediate data of the page. Here, if the intermediate data of the read page includes a command for referring to the cache ID, the intermediate data corresponding to the cache ID (that is, the intermediate data of the form) is read from the form cache 48 and read. By processing the intermediate data, form drawing data is generated and combined with the page drawing data.

In the above, in order to simplify the description, it has been described that the form is cached. However, in an actual apparatus, not all forms are cached. In order to use the cache, processing overhead such as registration to the cache and an inquiry about the presence or absence of necessary cache data occurs. If the form is very small or has a simple structure, the time required to generate the intermediate data can be very short, so considering the overhead of such processing, the processing is often faster without using a cache. . Therefore, in the present embodiment, only the forms that have better processing efficiency when cached are cached. For this reason, in the present embodiment, a rule for determining a form that has better processing efficiency when cached (that is, a cache target) and a form that is not so is defined. An example of this determination rule is shown below.
(Rule 1) If the number of pixels in the bounding box of the form (the smallest rectangle that can surround the form on the physical page) is greater than a predetermined number (referred to as a “pixel number threshold”), Form is cached, otherwise it is not cached.
(Rule 2) When the number of objects included in the form is larger than a predetermined number (referred to as “object number threshold”), the form is set as a cache target, and otherwise, the form is not set as a cache target.
(Rule 3) If there is an image (bitmap) larger than a predetermined size (referred to as “image size threshold”) in the form, the form is set as a cache target. Otherwise, the form is not set as a cache target.

  For example, the determination may be performed using any one of the rules 1 to 3 exemplified above, or the determination may be performed by combining two or more. When two or more are combined, if it is determined as “cache target” by at least one rule, the form is cached regardless of the determination result by other rules.

  The pixel number threshold, the object number threshold, and the image size threshold described above are values according to the system configuration and performance of the front-end device 30 and the back-end device 40, and may be determined through experiments, simulations, or the like.

  In the present embodiment, the logical page interpretation units 36-p1 and 36-p2 and the form interpretation unit 36-f determine whether or not the form is to be cached using a unified common determination rule. Therefore, for example, a form that the logical page interpretation unit 36-p1 determines to be cached is determined to be a cache target by both the logical page interpretation unit 36-p2 and the form interpretation unit 36-f.

  In the present embodiment, the logical page interpretation units 36-p1 and 36-p2 and the form interpretation unit 36-f use the unified common ID assignment rule to perform cache data (intermediate data) on the form. A cache ID is assigned. In this common ID assignment rule, in addition to the form ID assigned to the form in the PDL data, the form is determined in consideration of various parameters that define the state of the final rendered image of the form. The cache ID to be assigned to the cache data is determined. Even if a form with the same form ID is used, if the parameters for drawing and printing the form are different, the image of the form that finally appears on the printed matter will also be different, so if the parameters are different, they are handled as different cache data. It is. Parameters such as drawing that define the cache ID include a coordinate transformation matrix (matrix representing the rotation angle and scaling ratio of coordinates), drawing attribute information (eg, line width, line cap, line join, miter limit, line shape) Stroke adjustment, drawing method, logical operation mode, pattern information), clip information, color information, and the like. In one example, a combination of a form ID and these parameters is expressed as binary data, and a cache ID is generated from the binary data using a hash function such as an MD5 hash function (defined by rfc1321). The form ID and the parameter group used as the cache ID material are referred to as “key data”.

  Strictly speaking, since there is a collision in the hash function, the cache ID (hash value) of different cache data may be the same value in the above-described method. In order to avoid hash collision, the key data itself may be used as a cache ID.

  However, since the key data is quite long, it takes a certain amount of time to collate the key data when checking whether there is usable cache data. It takes a considerable amount of time to collate key data for all cache entries in the cache management unit 38. Therefore, in the following example, a combination of key data and a hash value of the key data is used as a cache ID. In this example, when the presence or absence of usable cache data is checked, the number of cache entries to be checked for key data is reduced by first narrowing down with hash values.

  As described above, in this embodiment, the logical page interpretation units 36-p1 and 36-p2 and the form interpretation unit 36-f use a common ID assignment rule. Therefore, for example, when a certain cache ID is generated for a form having the logical page interpretation unit 36-p1 (here, the logical page interpretation unit 36-p1 does not generate intermediate data of the form), the form interpretation unit 36-f. Generates the same cache ID, and registers the generated intermediate data of the form in the form cache 48 in association with the cache ID.

  Next, with reference to FIGS. 4 to 6, a procedure of processes executed by the logical page interpretation unit 36-p and the form interpretation unit 36-f will be exemplified.

  FIG. 4 shows a processing procedure common to the logical page interpretation unit 36-p and the form interpretation unit 36-f. In this example, PDL data described in non-page independent PDL is processed. In the description of FIG. 4, the logical page interpretation unit 36-p and the form interpretation unit 36-f are collectively referred to as the interpretation unit 36. These interpretation units 36 operate asynchronously independently of each other.

  In this procedure, the interpretation unit 36 acquires the entire PDL data of the print job from the print job reception unit 32 (S10). Next, an allocation of a page to be processed is received from the page distribution unit 34 (S12). Here, in the page distribution unit 34, the logical page interpretation units 36-p1 and 36-p2 share all pages of the PDL data, but the form interpretation unit 36-f handles all pages. The interpretation unit 36 interprets the PDL data of the allocated page (S14). When the interpretation of the page is completed, the interpretation unit 36 determines whether the interpretation of the entire print job is completed (S16). If it is determined that the interpretation is not completed, the process returns to S12 and the page distribution unit 34 is determined. Notify the end of page interpretation and receive the next assigned page assignment. The above processing is repeated until interpretation of the entire print job is completed.

  In the page interpretation process (S14), the interpreter 36 extracts PDL data commands one by one from the top of the page (S20), interprets the extracted commands, and generates intermediate data objects (S14). S22). These processes of S20 and S22 are repeated until the process of the last command on the page is completed (S24).

  When processing page-independent PDL data, each logical page interpreting unit 36-p interprets the commands of all pages regardless of whether or not it is a page for which it is responsible, In accordance with the result of the interpretation. For the page in charge, not only interpretation but also generation of intermediate data is performed. As a result, correct intermediate data reflecting the interpretation result from the first page is generated. Similarly, the form interpretation unit 36-f interprets all commands of PDL data including drawing commands for objects other than forms, and also generates intermediate data for drawing drawing commands.

  The content of the intermediate data generation process (S22) differs between the logical page interpretation unit 36-p and the form interpretation unit 36-f.

  FIG. 5 shows an example of the processing procedure of the intermediate data generation processing (S22) by the logical page interpretation unit 36-p. In this example, the logical page interpretation unit 36-p determines whether or not the command to be processed (extracted in S20) is a command instructing generation of a form object (S30). For example, in the case of PostScript (registered trademark), if the command name of the command to be processed is “form”, the command is a command for instructing generation of a form object. A command instructing generation of a form is accompanied by a form ID as a parameter.

  If the determination result in S30 is negative (N: command other than form generation), the logical page interpretation unit 36-p interprets the command to generate intermediate data (S32), and the intermediate data is converted into the page. Is output as intermediate data (S34).

  If the determination result in S30 is affirmative (Y: form generation command), the logical page interpretation unit 36-p determines whether the intermediate data of the form corresponding to the command is to be cached next as described above. The determination is made according to the determination rule (S36).

  If it is determined in S36 that the command is not a cache target (the determination result in S36 is N), the logical page interpretation unit 36-p extracts the form ID associated with the command, and the form ID corresponding to the form ID is extracted. The PDL data is acquired and expanded on the memory (S38). For example, there are cases where the form ID is shown only in the second and subsequent uses of the form in the PDL data, and the PDL data representing the form entity is not described. Even in such a case, the logical page interpretation unit 36-p manages the PDL data of the form read from the place where the form is first used in the PDL data of the print job in association with the form ID. In the second and subsequent use locations, the managed PDL data is read and used. After expanding the PDL data of the form, the logical page interpretation unit 36-p interprets the expanded PDL data, generates intermediate data (S32), and outputs the intermediate data (S34).

  If it is determined in S36 that the determination target command is a cache target (the determination result in S36 is Y), the logical page interpretation unit 36-p follows the unified ID assignment rule described above, and the cache corresponding to the command is determined. An ID is generated (S40). In S40, the value of each item constituting the key data is extracted from the parameter group such as the form ID attached to the command and the internal state information of the logical page interpretation unit 36-p itself, and the extracted values are combined. Key data is generated, and a hash value of the key data is calculated. The hash value / key data pair is used as a cache ID.

  Then, the logical page interpretation unit 36-p generates an intermediate data command instructing to refer to the cache data indicated by the cache ID, and outputs the generated intermediate data command (S42). As described above, for the cached form, the logical page interpretation unit 36-p generates a command for referring to the cache data instead of generating intermediate data representing the entity (image) of the form.

  FIG. 6 shows an example of the processing procedure of the intermediate data generation processing (S22) by the form interpretation unit 36-f. In this example, the form interpretation unit 36-f determines whether or not the command to be processed (extracted in S20) is a command instructing generation of a form object by the same method as S30 (S50). If the determination result in S50 is negative (N), the form interpretation unit 36-f does not perform any processing for the command and ends the processing in FIG.

  If the determination result in S50 is affirmative (Y), the form interpretation unit 36-f determines whether the intermediate data of the form corresponding to the command is to be cached next, as in S36. It judges according to a rule (S52).

  If it is determined in S52 that the command is not a cache target (the determination result in S52 is N), the form interpreter 36-f does not perform any processing on the command and ends the processing in FIG.

  If it is determined in S52 that the determination target command is a cache target (the determination result in S52 is Y), the form interpreter 36-f follows the unified ID assignment rule described above in the same manner as in S40. A cache ID corresponding to the command is generated (S54). Then, the command is interpreted to generate cache data (form intermediate data) (S56), and the generated cache data is output in association with the cache ID (S58). The output cache ID / cache data pair is registered in the form cache 48.

  In S56 and S58, duplicate generation and registration of the same cache data may be avoided. For this purpose, the form interpretation unit 36-f inquires of the cache management unit 38 whether or not the cache data corresponding to the cache ID generated in S54 exists in the form cache 48 before generating the cache data. It is only necessary to generate cache data only when an answer that it does not exist is obtained. When cache data is generated and registered in the form cache 48, the form interpretation unit 36-f registers the cache ID of the cache data in the cache management unit 38, thereby confirming that the cache data has been registered. Record.

  Next, an example of a processing procedure of the drawing unit 44 of the back-end device 40 will be described with reference to FIGS. 7 and 8.

  As shown in FIG. 7, in this procedure, the drawing unit 44 first receives designation of a print job to be processed (S100). Next, for example, the page intermediate data is acquired from the intermediate data buffer 42 one page at a time in order from the first page of the print job (S102), and the acquired intermediate data of the page is interpreted (S104). The processes of S102 and S104 are repeatedly executed page by page until the end of the print job (S106).

  In the intermediate data interpretation process (S104), the intermediate data commands are extracted one by one in order from the top of the page (S110), the extracted commands are interpreted, and the raster image indicated by the command is extracted. Drawing on the memory (S112). These processes of S110 and S112 are repeated until the process of the last intermediate data command of the page is completed (S114).

  In the page intermediate data interpretation process (S112), as shown in FIG. 8, the drawing unit 44 reads commands from the top of the page intermediate data in order from the top, and the read command instructs the cache data to be referenced (cache). It is determined whether it is referred to as a reference command (S120).

  If the determination result in S120 is affirmative (Y), the drawing unit 44 extracts a cache ID from the cache reference command (S122), and extracts cache data (intermediate data) corresponding to the cache ID from the form cache 48 ( In step S124, the fetched cache data is interpreted to render a raster image (ie, “rasterize”) (S126).

  If the determination result in S120 is negative (N), the drawing unit 44 interprets and rasterizes the command (S126).

  As described above, in this embodiment, the logical page interpretation unit 36-p and the form interpretation unit 36-f use the same ID assignment rule, and the same material (that is, the form ID and the form print result image). A cache ID is assigned from other parameters to be specified). Accordingly, the interpretation units 36 can attach the same cache ID to the same cache data without communicating with each other. Therefore, the cache data indicated by the cache ID of the cache reference command included in the intermediate data of the pages generated by the logical page interpretation units 36-p1 and 36-p2 is surely generated sooner or later by the form interpretation unit 36-f. It is registered in the form cache 48 in association with the ID. If the rendering unit 44 tries to process a cache reference command in a page and the cache data indicated by the command is not in the form cache 48, the rendering unit 44 stores the cache data in the form cache if it waits for a while. 48 can be obtained. While the first part of the print job is being processed, the progress of the generation of the form cache data by the form interpretation unit 36-f is not sufficient, and thus the waiting of the drawing unit 44 (waiting for completion of the cache data) occurs. The probability is somewhat high. While the logical page processing is performed in parallel by a plurality of logical page interpreting units 36-p, the form processing is performed in the page order by one form interpreting unit 36-f. Because there are times when it cannot catch up. However, since the form interpreter 36-f generates cache data only once, even if a form with the same key data appears, the process proceeds to some extent and when a considerable number of cache data is accumulated in the form cache 48, In general, the frequency at which new cache data needs to be generated is reduced. For this reason, the page processing speed is improved, and the progress of the processing of the logical page interpretation unit 36-p operating in parallel is overtaken. When this happens, the above-described drawing unit 44 does not wait for completion of cache data.

  As described above, even if the logical page interpretation units 36-p1 and 36-p2 and the form interpretation unit 36-f operate asynchronously independently of each other without performing inter-process communication, intermediate data of the form Can be cached and reused. This embodiment is faster in processing than a system that performs interprocess communication because there is no overhead for interprocess communication.

<Ratio control>
Next, control of the ratio between the logical page interpretation unit 36-p and the form interpretation unit 36-f in the front-end device 30 will be described. In the following description, it is assumed that the page distribution unit 34 performs this ratio control. However, another control unit may perform the ratio control.

  For the ratio control, the page distribution unit 34 grasps the progress degree of page interpretation by the logical page interpretation unit 36-p group and the progress degree of form interpretation by the form interpretation unit 36-f group. Each progress degree represents the length from the top of the PDL data of the print job to the interpreted portion (in other words, the position of the interpreted portion viewed from the top of the PDL data) as an index. That is, both the logical page interpretation unit 36-p and the form interpretation unit 36-f interpret in order from the top of the PDL data. To do.

  For example, a page number may be used as the unit of progress. For example, among n pages currently processed in parallel by n logical page interpreters 36-p (n is the total number of logical page interpreters 36-p currently operating in the front-end device 30). The number of the latest (last) page is used as an index value of the progress degree of logical page interpretation. Instead of the page currently being processed, the number of the latest page that the n logical page interpretation units 36-p have completed the interpretation, or the page distribution unit 34 applies to the n logical page interpretation units 36-p. The latest assigned page number may be used as the value of the degree of progress of logical page interpretation. Similarly, k (where k is the total number of form interpretation units 36-f currently operating in the front-end device 30) are currently processing in parallel or have completed interpretation. The latest page number among the k pages, or the latest page number assigned to the k form interpretation units 34 by the page distribution unit 34 may be used as an index value of the progress degree of form interpretation.

  In the above, the example in which the index value of the progress of the interpretation process is represented by the page number is shown, but this is only an example. For example, the degree of progress may be expressed by the number of bands on which page and how many bands have been interpreted. A band is a band-like range obtained by dividing a page into a plurality of parts in the sub-scanning direction. Further, the progress of interpretation may be expressed in units of tiles (that is, the page is composed of a plurality of tiles) that is a result of dividing the page into a plurality of parts in both the main scanning direction and the sub-scanning direction. In the following, an example in which the progress of interpretation is represented by a page number will be described as a representative.

  An example of the processing procedure of the control of the composition ratio of the interpretation unit performed by the page distribution unit 34 is shown in FIG. In the example of FIG. 9, the front-end device 30 has two interpretation units dedicated to interpretation of a logical page and one dual-use interpretation unit that can function as both the logical page interpretation unit 36-p and the form interpretation unit 36-f. This is an example of control when a total of three interpretation units 36 are provided. That is, this example is considered to be an example in the case where the logical page interpretation units 36-p1 and 36-p2 are interpretation units dedicated to logical pages and the form interpretation unit 36-f is a dual-use interpretation unit in the example of FIG. That's fine. In this example, since there is only one dual-use interpreter, the dual-use interpreter (the third interpreter 36-f from the top in the example of FIG. 3) functions as a form interpreter or a logical page interpreter. It will be controlled whether to function as a part.

  In the procedure of FIG. 9, first, the page distribution unit 34 sets, as the form interpretation unit, the only dual-use interpretation unit of the front-end device 30 at the start of processing of PDL data to be printed (S1002). That is, the dual interpretation unit is instructed to function as a form interpretation unit. As a result of this instruction, the front-end device 30 has two logical page interpretation units 36-p1 and 36-p2 and one form interpretation unit 36-f as shown in FIG.

  In this state, the page distribution unit 34 assigns different pages to the logical page interpretation units 36-p1 and 36-p2 in order from the first page of the PDL data. For example, each logical page interpretation unit 36-p sends a completion notification to the page distribution unit 34 every time it completes the interpretation (intermediate data generation) of one logical page, and the page distribution unit 34 responds to the completion notification to the logical page. The next logical page is allocated to the interpreter 36-p. Further, the page distribution unit 34 causes the form interpretation unit 36-f to execute form interpretation in order from the first page. The form interpretation unit 36-f may send a completion notification to the page distribution unit 34 every time the interpretation of the form group in one page is completed.

  Here, the page distribution unit 34 monitors how many pages of the print job have been interpreted by the logical page and the form. This monitoring may be performed using, for example, a completion notification sent from the logical page interpretation unit 36-p and the form interpretation unit 36-f to the page distribution unit 34. For example, in the example of FIG. 3, a notification of completion of the third page is received from the logical page interpretation unit 36-p1 (the completion notification of the next allocated fifth page has not arrived), and the logical page interpretation unit 36-p2 When the notification of the completion of the fourth page is received from (the completion notification of the next allocated sixth page has not arrived), the two logical page interpretation units 36-p1 and 36-p2 as a whole reach the fourth page. It is determined that the logical page interpretation is complete. In the case of only one form interpretation unit 36-f, it is simpler. When n page completion notifications are received from the start of the print job, the form interpretation up to the nth page is completed. Can be judged. If there are a plurality of active form interpreting units 36-f in the front-end device 30, the progress of the form interpreting process is determined based on the number of pages that have been interpreted by the plurality of form interpreting units 34-f. The latest page number may be used.

  In the above, the progress of interpretation is represented by the latest page number where the interpretation is “completed”. If 1 is added to this page number, the logical page interpretation unit 36-p group (or the form interpretation unit 36-f group). ) Is the latest page number currently being interpreted. The latest page number currently being interpreted may be used as an index value for the degree of progress.

  Further, the page distribution unit 34 sequentially assigns pages from the first page to the logical page interpretation unit 36-p according to a predetermined algorithm, so that it can grasp how many pages have been allocated. ing. The assigned latest page number may be used as an index value for the degree of progress.

  As exemplified above, the page distribution unit 34 obtains and updates index values of the progress levels of logical page interpretation and form interpretation as the print job process proceeds. Then, the page distribution unit 34 compares the index value of the progress degree of logical page interpretation with the index value of the progress degree of form interpretation at a certain determination timing (S1004, S1012). The determination timing may be, for example, a regular timing every predetermined time, or the interpretation of one page is completed from the logical page interpretation units 36-p1 and 36-p2 or the form interpretation unit 36-f. It may be the timing each time a notification comes.

  First, in S1004, it is determined whether the progress of form interpretation is sufficiently larger than the progress of logical page interpretation. In this determination, for example, the leading degree of the progress of the interpretation of the form with respect to the progress of the interpretation of the logical page is calculated, and it is determined whether or not the leading degree is larger than a predetermined threshold Th1. This leading degree is, for example, a subtraction result obtained by subtracting the progress degree of the logical page interpretation from the progress degree of the form interpretation. It is represented by (Pf−Pp). In this case, in S1004, it is determined whether or not “(Pf−Pp)> Th1” is satisfied. If true, the determination result in S1004 is affirmative (Y), and if not, negative (N).

  Here, the threshold value Th1 is the number of pages that serves as a criterion for determining whether the progress of form interpretation is “sufficiently” ahead of the progress of logical page interpretation. The value of the threshold Th1 is an integer larger than the threshold Th2 used in the determination in S1012 described later.

  When the determination result in S1004 is Y, the page distribution unit 34 sets the dual interpretation unit (indicated as the form interpretation unit 36-f in FIG. 3) as the logical page interpretation unit (S1006). That is, the dual interpreter is instructed to function as the logical page interpreter 36-p. As a result of this instruction, the front-end device 30 enters a state in which the three logical page interpretation units 36-p operate. That is, in this case, since the interpretation of the form is sufficiently advanced to the previous page, the image processing (interpretation and interpretation) of the entire system is increased by increasing the number of logical page interpretation units 36-p to increase the logical page interpretation speed. Speed of drawing).

  Then, the page distribution unit 34 allocates pages to the three logical page interpretation units 36-p (S1008), and determines whether the allocation has been completed up to the last page of the print job (S1010). If the determination result in S1010 is Y, the page distribution unit 34 ends the process for this print job. Conversely, if the determination result is N, the process returns to S1004.

  When the determination result in S1004 is N, the page distribution unit S34 determines whether the progress of form interpretation has been caught up with the progress of logical page interpretation (S1012). If the result of this determination is Y, that is, it has been determined that “it has been caught up”, the dual interpretation unit is set as the form interpretation unit (S1014). For example, when all the three interpreting units 36 have been operating as the logical page interpreting unit 36-p so far and the determination result in S1012 is Y, one of them is switched to the form interpreting unit 36-f, Form interpretation will resume. As a result, the remaining two logical page interpretation units 36-p interpret the form used in each page to be processed from now on, and the interpretation result is accumulated in the form cache 48. After S1014, the process proceeds to S1008.

  If the determination result in S1012 is N, S1014 is skipped, so the operation mode of the dual interpretation unit is not changed.

  Here, in the determination in S1012, for example, it is determined whether or not the leading degree (Pf−Pp) of the form interpretation with respect to the logical page interpretation is equal to or less than the second threshold Th2. If (Pf−Pp) ≦ Th2 is satisfied, the determination result in S1012 is Y.

  The second threshold Th2 may be 1, for example. In this case, when the form interpretation is completely overtaken by the logical page interpretation (that is, the leading degree = 0), the determination result in S1012 is Y.

  As another example, “the interpretation result of the form used up to the next page to be processed next by the logical page interpretation unit 36-p group in the front-end device 30 is accumulated in the form cache 48”. The value of Th2 may be determined so that the condition is satisfied. For example, in the case of a system configuration in which there are two interpretation units dedicated to logical pages and one interpretation unit for both examples, the conditions imposed on the form interpretation carried by the interpretation units for both are two dedicated logical page interpretation units. 36-p1 and 36-p2 cache the form interpretation results up to the next page to be processed. In this case, Th2 is the number of logical page interpretation units remaining when the dual interpretation unit operating as the logical page interpretation unit is switched to the form interpretation unit (in this example, dedicated logical page interpretation units 36-p1, 36- The number may be “4”, which is twice the number of p2 = 2). That is, if the maximum number of logical pages that have been interpreted at the present time is k, the maximum number of logical pages currently processed by the two logical page interpreters 36-p1 and 36-p2 is (k + 2). The maximum number of pages to be processed next by these logical page interpretation units is (k + 4). Therefore, in order to satisfy the above-described condition, the form interpretation must be completed up to four pages ahead of the page number where the logical page interpretation is completed.

  For example, considering the time point when the leading degree of form interpretation (Pf−Pp) has changed from Th2 = “4” to Th2 = “4” or less, the form cache 48 at that time has two logical pages. The interpretation result of the form used in the page to be processed next by the interpretation units 36-p1 and 36-p2 is barely accumulated or slightly less than that. Therefore, in order to proceed with the interpretation of the form, the dual-purpose interpretation unit that has been functioning as the logical page interpretation unit is switched to the form interpretation unit.

  The threshold value Th2 for satisfying the above condition may be twice the total number of the dedicated logical page interpretation units 36-p as illustrated above, but the time required for switching from the logical page interpretation unit to the form interpretation unit, In consideration of the control time delay due to other factors, the value may be set to a value somewhat larger than “total number of dedicated logical page interpretation units 36-p × 2”.

  Moreover, what is necessary is just to determine the specific value (value larger than Th2) of the above-mentioned 1st threshold value Th1 on the basis of the 2nd threshold value Th2 defined in this way.

  FIG. 10 shows a specific example of the first processing flow of a print job for a front-end device including three dedicated logical page interpretation units and one dual-purpose interpretation unit. In this example, the three logical page interpreters first interpret the pages 1, 2, and 3, respectively, and the dual interpreter functioning as the form interpreter interprets the forms contained in the page in order from the first page. To proceed. For example, the top logical page interpretation unit interprets the fourth page after the interpretation of the first page is completed. Thereafter, when the dual interpretation unit functioning as the form interpretation unit finishes interpreting the form group in the sixteenth page, the three logical page interpretation units complete the interpretation up to the sixth page, Interpretation of ~ 9 pages is in progress. In this example, the first threshold Th1 is “9”, and the leading degree “10” (= 16−6) of the form interpretation at this time is greater than the threshold Th1, so the determination result in S1004 is Y, and both The interpreter is switched to the mode of the logical page interpreter. Then, the interpretation of the tenth page is assigned to the dual interpretation unit functioning as the fourth logical page interpretation unit.

  After that, when the dual interpretation unit functioning as the logical page interpretation unit completes the interpretation of the tenth page, the three logical page interpretation units are processing the 11th to 13th pages. At this time, the leading degree of form interpretation is “6”, which is the result of subtracting the latest page number 10 for which logical page interpretation has been completed from the latest page number 16 for which form interpretation has been completed. The leading degree value 6 is a value equal to or smaller than the determination threshold Th2 = 6 (twice the total number of dedicated logical page interpretation units 3) in S1012. Therefore, the determination result in S1012 is Y, and the dual-purpose interpreter is switched to the form interpreter mode in S1014. As a result, the dual-purpose interpreter proceeds with the interpretation of the forms on the 17th and subsequent pages.

  In the above, the case where the number of the dual interpretation units in the front end device 30 is one has been described. Next, an example of control of the component ratio of the interpretation unit when two dual-purpose interpretation units are provided in the front-end device 30 will be described with reference to FIG. As long as the number of interpretation sections dedicated to logical page interpretation is one or more, any number is acceptable.

  In this example, first, at the beginning of execution of a print job, two dual-purpose interpreters are set in a logical page interpreter and a form interpreter at a predetermined ratio (S1022). For example, if the “predetermined ratio” is 1: 1, one of the two dual-purpose interpreters is set as the logical page interpreter, and the other is set as the form interpreter. However, this is merely an example, and instead of this, both of the two interpretation units may be initially set as the form interpretation unit.

  The page distribution unit 34 monitors the progress of each of the form interpretation and the logical page interpretation, and determines whether or not the leading degree of the form interpretation with respect to the logical page interpretation is sufficiently large every time the determination timing comes. (S1024). In S1024, it is determined whether or not the leading degree exceeds a predetermined threshold value ThA. This threshold value ThA is a predetermined value that is larger than a determination threshold value ThB in S1032 described later. When the determination result in S1024 is Y (positive), the page distribution unit 34 sets both of the two dual-purpose interpretation units as the logical page interpretation unit (S1026). In S1026, the dual interpretation unit that has already been operating as the logical page interpretation unit before S1026 continues to operate as the logical page interpretation unit, and the dual interpretation unit that is operating as the form interpretation unit before S1026 is Switch to the logical page interpreter. As described above, in S1026, if the interpretation of the form has been completed up to a sufficiently long page, the number of logical page interpretation units is increased to increase the speed of logical page interpretation, thereby improving the processing speed of the print job. It is. Then, pages are allocated to each logical page interpretation unit (S1028), and it is determined whether the interpretation is completed up to the last page of the print job (S1030).

  When the determination result in S1024 is N, the page distribution unit 34 determines whether or not the advance degree of form interpretation is greater than the second threshold ThB (S1032). The second threshold ThB is a threshold for determining whether or not the form interpretation has been caught up with the logical page interpretation, like the threshold Th2 in the above example. If the result of the determination in S1032 is N (No), it means that the form interpretation has been caught up with the logical page interpretation, and therefore it is necessary to advance the form interpretation at high speed. Therefore, in this case, both interpretation units are set as form interpretation units (S1036). In S1036, the dual-use interpreter that has been operating as the form interpreter before S1036 continues to operate as the form interpreter, and the dual-use interpreter that is operating as the logical page interpreter before S1036 Switch to the interpreter. By operating the two form interpretation units in this way, the form interpretation speed is increased.

  When the determination result in S1032 is Y, the leading degree of form interpretation is between the first threshold ThA and the second threshold ThB. This situation is between a situation where the form interpretation is too predecessor and a situation where the form interpretation is likely to be caught up with the logical page interpretation. In this situation, one of the two dual-purpose interpreting units functions as a logical page interpreting unit, and the other functions as a form interpreting unit (S1034). As a result, the form interpretation can be made more difficult to catch up with the logical page interpretation by increasing the speed of the form interpretation than when both the two-purpose interpretation units are operated as the logical page interpretation unit.

  In the example of FIG. 11 described above, two form interpretation units may operate in parallel. In such a case, the intermediate data of the interpretation results of the two form interpretation units are centrally managed by the cache management unit 38 (see FIG. 3) of one form interpretation unit, so that the two form interpretation units have the same form. Duplicate interpretation may be prevented. That is, in this case, only a predetermined one of the two dual-use interpretation units has the cache management unit 38, and if only one dual-use interpretation unit is set as the form interpretation unit, the cache management unit 38 is provided. Will be set in the form interpretation section. When the two interpretation units are form interpretation units, the form interpretation unit that does not have the cache management unit 38 sets the cache ID corresponding to the form every time a new form is detected from the PDL data. The form interpretation unit having the cache management unit 38 is inquired as to whether the interpretation result corresponding to the cache ID has already been registered. If it is determined as a result of the inquiry that the registration is already registered, the interpretation of the form is canceled and the process proceeds to the next form. If the registration is not registered, the form is interpreted.

  FIG. 11 shows an example of the case where there are two dual-use interpreters in the front-end device 30 (the dedicated logical page interpreter is an arbitrary number greater than or equal to 1). The present invention is also applicable when there are three or more. In other words, the degree of precedence of the logical interpretation of the form interpretation is monitored, and as the precedence decreases, the number of dual interpretation units to be operated as the form interpretation unit is increased stepwise (that is, the logical page interpretation unit is operated). The efficiency of the entire interpretation process can be increased by performing control (reducing the number of objects step by step).

  Next, with reference to FIG. 12, the further modification about control of the structure ratio of an interpretation part is demonstrated. Of the procedure of the composition ratio control shown in FIG. 12, the same steps as those in the procedure of FIG. In the example of FIG. 12, it is assumed that the front-end device 30 includes a plurality of dual-purpose interpretation units and one or more dedicated logical page interpretation units.

  In the procedure of FIG. 12, first, at the start of execution of a print job, a plurality of interpretation units in the front-end device 30 are set as a logical page interpretation unit and a form interpretation unit according to a predetermined initial ratio (S1022). Assign a page to the interpreter and execute the process.

  Then, the leading degree of the form interpretation with respect to the logical page interpretation is calculated, and when the obtained leading degree is equal to or less than a predetermined threshold ThB (the determination result of S1032 is N), the dual-use interpretation that has been functioning as the logical page interpretation unit until then One of the units is switched to the form interpretation unit (S1044). Thereby, the number of form interpretation parts increases by one. The threshold value Thb used here is a threshold value for determining whether or not the form interpretation has been caught up with the logical page interpretation, like the threshold value Th2 in the above-described example. This increases the speed of form interpretation and reduces the possibility that form interpretation will be overtaken by logical page interpretation.

  On the other hand, when the leading degree of the form interpretation exceeds the threshold ThA larger than the threshold ThB (the determination result in S1024 is Y), one of the dual-use interpretation units that has been functioning as the form interpretation unit until then is determined. Switching to the logical page interpretation unit (S1042). As a result, the logical page interpretation speed is improved, and the printing speed is improved.

  When the leading degree of form interpretation is equal to or less than the threshold ThA and greater than ThB, switching from the logical page interpretation unit to the form interpretation unit and vice versa are not performed. Therefore, in this case, the ratio between the logical page interpretation unit and the form interpretation unit is maintained.

  The switching from the logical page interpreting unit to the form interpreting unit and the switching from the form interpreting unit to the logical page interpreting unit do not have to be performed one by one as in the above-described example, and may be performed by a plurality.

  In the embodiment described above, the ratio of the number of form interpreters to the number of logical page interpreters is set so that the progress of form interpretation cannot catch up with the progress of logical page interpretation (that is, form interpretation always precedes logical page interpretation). Although controlled, this is not essential. Conversely, the logical page interpretation may be controlled to precede the form interpretation. Further, it may be a control in which either logical page interpretation or form interpretation may precede.

  In any case, it is important to control the progress of the form interpretation and the logical page interpretation so that there is no significant difference. The drawing unit 44 can perform drawing up to a page where both the interpretation result of the logical page and the interpretation result of the form used in the logical page are available. That is, the drawing speed of the drawing unit 44 is limited to the slower speed of logical page interpretation and form interpretation. For this reason, even if one of the logical page interpretation and the form interpretation is significantly faster than the other, the drawing speed of the drawing unit 44 (and consequently the speed of the entire printing process) is not improved. Rather, in a situation where the total number of interpretation units 36 is determined, it is possible to improve the overall processing speed by preventing a large difference between the progress of form interpretation and the progress of logical page interpretation. For example, in the procedure of FIG. 12, if the threshold ThB used in S1032 is a negative value, either logical page interpretation or form interpretation may precede, and the progress degree of logical page interpretation and the progress degree of form interpretation The difference can be made to fall within a certain range.

  In the foregoing, an example in which one or more dedicated logical page interpretation units and one or more dual interpretation units exist in the front-end device 30 has been mainly described. On the other hand, the various controls exemplified above can be applied to a system configuration in which the plurality of interpretation units 36 in the front-end device 30 are all dual-use interpretation units. When all of the plurality of interpretation units 36 are dual-use interpretation units, in the initial setting (S1022), not all of the dual-use interpretation units are set as form interpretation units, but some are set as logical page interpretation units. The ratio of the number of logical page interpretation units and form interpretation units at the time of initialization is a predetermined ratio.

  In the above, embodiment and the modification of this invention were demonstrated. The above-described embodiments and modifications are merely examples for explaining the present invention, and the scope of the present invention is not limited to the above-described embodiments and modifications. For example, in the above embodiment, the form cache 48 is provided in the back-end device 40, but this is merely an example. The form cache 48 may be arranged in any place as long as it is accessible from each interpretation unit 36 and drawing unit 44. In the above-described embodiment, the number of the drawing units 44 is one.

10 terminal device, 20 print controller, 30 front-end device, 32 print job reception unit, 34 page distribution unit, 36-f form interpretation unit, 36-p1, 36-p2 logical page interpretation unit, 38 cache management unit, 40 back End device, 42 Intermediate data buffer, 44 Rendering unit, 46 Output buffer, 48 Form cache, 50 Printing device, 60, 62, 64 Communication means, 382 Communication control unit, 384 Cache control unit, 386 Cache table.

Claims (5)

Logical page interpreting means for interpreting logical pages in print data and outputting interpretation results; and for cache for interpreting cache target elements included in each logical page in print data and storing interpretation results in cache means One or more dual-purpose interpretation means capable of functioning as interpretation means;
Switching means for switching whether to make each of the dual-purpose interpretation means function as the logical page interpretation means or the cache interpretation means;
Generate print image data of each logical page using the interpretation result of each logical page output from each logical page interpreting means and the interpretation result of the cache target element stored in the cache means, and generate Print image data generation means for supplying the print image data to the printing apparatus;
Have
When the cache interpreting unit finds a cache target element whose interpretation result is not stored in the cache unit from the print data, the cache interpreting unit interprets the found cache target element, and the interpretation result is determined according to a predetermined generation rule. In association with the cache identification information generated from the data of the cache target element is stored in the cache means,
Each of the logical page interpreting means includes, for each cache target element included in the logical page to be processed, cache identification information generated according to the generation rule from the data of the cache target element instead of interpreting the cache target element. Generate a cache reference command, incorporate the generated cache reference command into the interpretation result of the logical page as the interpretation result of the cache target element,
When the print image data generating unit finds the cache reference command from the interpretation result of the logical page when generating the print image data from the interpretation result of the logical page output by the logical page interpretation unit, the cache reference An interpretation result corresponding to the cache identification information included in the command is acquired from the cache unit, and print image data of a cache target element corresponding to the cache identification information is generated using the acquired interpretation result, and the logic Composite to the print image data of the page,
The switching unit is based on a difference between a progress level of interpretation of the cache target element in the print data by the cache interpretation unit and a progress level of interpretation of the logical page in the print data by the logical page interpretation unit. , Controlling the ratio of the one or more dual-use interpreting means to function as the cache interpreting means and the logical page interpreting means to function.
A printed image processing system.   The switching means has a difference between a progress degree of interpretation of the cache target element in the print data by the cache interpretation means and a progress degree of interpretation of the logical page in the print data by the logical page interpretation means in advance. 2. The ratio of the one or more dual-use interpreting means that functions as the cache interpreting means and the one that functions as the logical page interpreting means is controlled so as to be within a predetermined range. The print image processing system described in 1.   The switching means is obtained by subtracting the progress of interpretation of the logical page in the print data by the logical page interpretation means from the progress of interpretation of the cache target element in the print data by the cache interpretation means. 3. The print image processing system according to claim 1, wherein a ratio of the one or more dual-purpose interpretation units that function as the cache interpretation unit is reduced as the leading degree increases.   The switching means is obtained by subtracting the progress of interpretation of the logical page in the print data by the logical page interpretation means from the progress of interpretation of the cache target element in the print data by the cache interpretation means. The print image processing according to any one of claims 1 to 3, wherein a ratio of the one or more dual-purpose interpreting units that function as the cache interpreting unit is increased as the leading degree is smaller. system. Computer
Logical page interpreting means for interpreting logical pages in print data and outputting interpretation results; and for cache for interpreting cache target elements included in each logical page in print data and storing interpretation results in cache means One or more dual-purpose interpretation means capable of functioning as interpretation means;
Switching means for switching whether to make each of the dual-purpose interpretation means function as the logical page interpretation means or the cache interpretation means;
Generate print image data of each logical page using the interpretation result of each logical page output from each logical page interpreting means and the interpretation result of the cache target element stored in the cache means, and generate Print image data generation means for supplying the printed image data to the printing apparatus,
Is a program for functioning as
When the cache interpreting unit finds a cache target element whose interpretation result is not stored in the cache unit from the print data, the cache interpreting unit interprets the found cache target element, and the interpretation result is determined according to a predetermined generation rule. In association with the cache identification information generated from the data of the cache target element is stored in the cache means,
Each of the logical page interpreting means includes, for each cache target element included in the logical page to be processed, cache identification information generated according to the generation rule from the data of the cache target element instead of interpreting the cache target element. Generate a cache reference command, incorporate the generated cache reference command into the interpretation result of the logical page as the interpretation result of the cache target element,
When the print image data generating unit finds the cache reference command from the interpretation result of the logical page when generating the print image data from the interpretation result of the logical page output by the logical page interpretation unit, the cache reference An interpretation result corresponding to the cache identification information included in the command is acquired from the cache unit, and print image data of a cache target element corresponding to the cache identification information is generated using the acquired interpretation result, and the logic Composite to the print image data of the page,
The switching means is based on a difference between a progress degree of interpretation of the cache target element in the print data by the cache interpretation means and a progress degree of interpretation of the logical page in the print data by the logical page interpretation means. , Controlling the ratio of the one or more dual-use interpreting means to function as the cache interpreting means and the logical page interpreting means to function.
A program characterized by that.

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