JP2015022685A - Image forming apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an image forming apparatus that executes optimal parallel processing irrespective of the number of pages of PDL data in a multi-core CPU to process the PDL data at a high speed.SOLUTION: In a multi-core CPU, an image forming apparatus determines pages to be processed, and switches to PDL parallel processing in an object unit on the first page and switches to PDL parallel processing in a page unit on the second and subsequent pages. When executing the processing on the remaining one page, the image forming apparatus then switches to the PDL parallel processing in an object unit so as to obtain the optimal performance improvement effect on both single-page data and multiple-page data.

Description

  The present invention relates to an image forming apparatus. The present invention relates to an image forming apparatus such as a printing apparatus provided with means for processing page description language (PDL) data by a plurality of processors.

  In recent years, due to improvements in hardware technology, multi-core CPUs have been developed, and a PC or the like can simultaneously execute a plurality of applications.

  A multi-function printer (MFP) is also equipped with a multi-core CPU in order to execute a plurality of functions such as copying and printing in parallel without stress. In the MFP, the PDL data print process has a very high CPU usage rate, and a method has been proposed in which each page is processed in parallel (page parallel process) using a multi-core CPU and printed at a higher speed. (See Patent Document 1).

  In addition, a method has been proposed in which commands in the PDL data are rearranged, and then each command is executed in parallel on an object basis (object parallel processing) by each CPU and processed efficiently by a multi-core CPU. (For example, refer to Patent Document 2).

Japanese Patent Laid-Open No. 05-201077 JP 2009-259231 A

  However, the PDL page parallel processing described above can efficiently utilize the multi-core CPU for a plurality of pages of data, but has no effect on single-page data. The PDL object parallel processing described above is effective for single-page data, but a system call between threads is generated in units of objects, and the effect is lower for multi-page data than for page parallel processing.

  Therefore, the present invention provides an image forming apparatus that processes PDL data at high speed by executing optimal parallel processing regardless of the number of pages of PDL data in a multi-core CPU.

To solve the above problem,
A page parallel processing means (402, 403) for processing a plurality of pages in parallel by a plurality of PDL processes for PDL data, an object parallel processing means (404, 405) for processing objects in a page in parallel, and A page determination unit (213) that analyzes PDL data and determines a page in an image forming apparatus (101) that executes a parallel processing unit with a plurality of CPUs (204);
Status management means (501, 502) for managing page processing statuses of a plurality of PDL processes executed by the page parallel processing means;
Depending on the page determination means and the status management means, the process switching means (S1003, S1022, S1103) for switching whether to execute the object parallel processing means, and the processing status managed by the status management means. And page processing control means (S1031, S1013) for switching the page processing execution of the page parallel processing,
The object parallel processing means performs parallel processing of PDL analysis and DL (Display List) generation in a pipeline on a per-object basis,
The process switching means, when it is determined that the page determined by the page determination means is the first page, PDL processing of the page by the object parallel processing means,
Furthermore, the process switching means includes an end determination means for determining whether any of the PDL processes has been completed from the statuses of the plurality of PDL processes managed by the status management means, and the PDL that has been terminated by the end determination means. When there is a process and an unfinished PDL process, the unfinished PDL process is switched to the object parallel processing means,
When the page processing control unit determines from the status of the plurality of PDL processes managed by the status management unit that the first page is being processed, the PDL process of the first page Control is performed so that the process waits until the process ends.

  In the multi-core CPU, the page to be processed is determined. If the first page, the PDL parallel processing in units of objects is switched, and the second and subsequent pages are switched to the PDL parallel processing in units of pages. Further, when the page processing is only one page, the optimum performance improvement effect can be obtained for single page data or multiple page data by switching to PDL parallel processing in object units.

1 is a diagram illustrating an example of a system configuration of an image forming apparatus 101 according to the present invention. The figure which shows an example of the module structure of the PDL process in this invention The figure which shows an example of the task structure of the PDL process in this invention The figure which shows the flowchart of the PDL control part 212 of the PDL control task 401 in Example 1. FIG. The figure which shows an example of the PDL task execution information which the PDL control part 212 in Example 1 manages. The figure which shows an example of the PDL task execution information which the PDL control part 212 in Example 1 manages. The figure which shows an example of the PDL task execution information which the PDL control part 212 in Example 1 manages. The figure which shows an example of the PDL task execution information which the PDL control part 212 in Example 1 manages. The figure which shows an example of the PDL task execution information which the PDL control part 212 in Example 1 manages. The figure which shows the flowchart of the process performed by PDL task 1 (402) in Example 1, and PDL task 2 (403). The figure which shows the flowchart of the pipeline process of S1104 in Example 1. FIG. The figure which shows the flowchart of the process performed by the pipeline task in Example 1. The figure which shows the flowchart of the normal process of step S1105 in Example 1. FIG.

  FIG. 1 is a diagram illustrating an example of a system configuration of an image forming apparatus 101 according to the present invention.

  Reference numeral 101 denotes an image forming apparatus, and 201 denotes a ROM that stores a control code of the CPU 204 in the image forming apparatus 101. The ROM 201 includes a reception unit 211, a PDL control unit 212, a PDL analysis unit 213, a DL generation unit 214, a pipeline processing unit 215, and a development processing unit 216. A RAM 202 temporarily stores various information. The RAM 202 includes a reception buffer 221, a work memory 222, a frame buffer 223, and a raster memory 224. Reference numeral 203 denotes a network I / F for inputting / outputting information to / from an external device, and receives print data transmitted from the external device.

  A reception unit 211 stores the PDL data received by the network I / F 203 in the reception buffer 221. A PDL control unit 212 controls processing execution of the PDL analysis unit 213, the DL generation unit 214, and the pipeline processing unit 215 and manages the processing status. Also, the PDL control unit 212 reads the PDL data stored in the reception buffer 221 in response to a request from the PDL analysis unit 213 and passes it to the PDL analysis unit 213. Reference numeral 213 denotes a PDL analysis unit that analyzes a PDL data command passed from the PDL control 212 and generates DL generation information.

  Reference numeral 214 denotes a DL generation unit that generates DL (Display List (intermediate code)) that is internal information for performing drawing from the DL generation information generated by analysis in the analysis unit 213, and stores the DL in the frame buffer 223. . A pipeline processing unit 215 temporarily spools DL generation information generated by command analysis by the PDL analysis unit 213 in the work memory 222, reads the asynchronously generated DL generation information, and passes the DL generation information to the DL generation unit 214. Reference numeral 216 denotes a decompression processing unit that decompresses the DL stored in the frame buffer 223 and stores the bitmap in the raster memory 224.

  The reception buffer 221 is a memory that stores print data received via the network I / F 203. A work memory 222 is temporarily used for generating DL generation information from PDL data, for storing DL generation information, and the like. A frame buffer 223 stores the DL generated by the DL generation unit 214. A raster memory 224 stores a raster image developed by the development processing unit 215 from the DL stored in the frame buffer 223.

  A multi-core central processing unit (CPU) 204 can perform arithmetic processing and control of the image forming apparatus 101 in parallel. Reference numeral 205 denotes an engine I / F that inputs and outputs signals with the printer engine 206. Reference numeral 206 denotes a printer engine that forms a latent image on a photosensitive drum by a known electrophotographic process based on image data, transfers the image onto a sheet, fixes it, and performs printing.

  FIG. 2 is a diagram showing a module configuration of PDL processing in the present invention.

  The PDL processing includes a PDL control unit 212, a PDL analysis unit 213, a DL generation unit 214, and a pipeline processing unit 215. The PDL analysis unit 213 and the DL generation unit 214 are executed from a plurality of tasks, and a plurality of pages are arranged in parallel. Can be done with. When receiving the notification of reception of PDL data from the reception unit 211, the PDL control unit 212 requests the PDL analysis unit 213 to perform processing. The PDL analysis unit 213 switches the DL generation unit 214 or the pipeline processing unit 215 in accordance with an instruction from the PDL control unit 212, and passes the DL generation information created by the PDL analysis.

  The pipeline processing unit 215 includes a spooler 301 that stores DL generation information, a spool 302 that stores DL generation information, and a despooler 303 that reads DL generation information stored in the spool 302. By executing the spooler 301 and the despooler 303 as separate tasks, the PDL analysis of the PDL analysis unit 213 and the DL generation of the DL generation unit 214 can be processed in parallel using the multi-core CPU 204.

  FIG. 3 is a diagram showing a task configuration of PDL processing in the present invention.

  401 is a PDL control task for executing the PDL control unit 212. The PDL control task 401 is activated when PDL data is received from the network I / F 203, generates PDL tasks 402 and 403 after activation, performs mutual message communication, and manages PDL data processing control and processing status. Reference numerals 402 and 403 denote PDL tasks 1 and 2 that receive the PDL processing request message from the PDL control unit 212 and execute by switching between the PDL analysis unit 213 and the DL generation unit 214 or between the PDL analysis unit 213 and the spooler 302. The PDL tasks 402 and 403 transmit a PDL page processing instruction request, a page end message, and a job end message to the PDL control task 401.

  Reference numerals 404 and 405 denote pipeline tasks 1 and 2 that are generated by the PDL tasks 402 and 403 and execute the despooler 303 and the DL generation unit 214. Note that the number of PDL tasks and pipeline tasks generated can be changed according to the number of CPUs.

[Example 1]
FIG. 4 is a diagram illustrating a flowchart of the PDL control unit 212 of the PDL control task 401 operating on the CPU 204 in this embodiment.

  In step S1001, PageCount for managing page numbers is initialized (1 is set) and task execution information is initialized. In step S1002, PDL tasks 1 and 2 are activated, and a message reception wait from PDL tasks 1 and 2 is awaited. When the message is received, it is determined in step S1003 whether it is a page processing instruction request. If it is a page processing instruction request message, it is determined in step S1004 whether PageCount is 1. If PageCount is 1, in step S1005, the page count page and pipeline processing request message are sent to the task that sent the message.

  In step S1042, PageCount and “Exec” indicating that processing is being executed are set in the PDL task execution information. In step S1043, PageCount is incremented and a message reception is waited (step S1002). On the other hand, if PageCount is other than 1, it is further determined in step S1031 whether PageCount is 2. If PageCount is 2, in step S1032, PageCount and “Wait” indicating the processing wait state are set in the PDL task execution information, and the message reception is waited (step S1002).

  As a result, for the processing of the first page, the objects can be executed in parallel by pipeline processing using a plurality of CPUs, and the printing time of the first page can be shortened. If PageCount is neither 1 nor 2, in step S1041, a PageCount page and a normal processing request message are transmitted to the task of the message transmission source. In step S1042, PageCount and “Exec” indicating that processing is being executed are set in the PDL task execution information. In step S1043, PageCount is incremented and a message reception is waited (step S1002).

  If the received message is not a page processing instruction request, it is determined in step S1011 whether it is a page end notification. If it is a page processing notification, in step S1012, "End" indicating the end of processing is set in the PDL task execution information. In step S1013, it is determined whether there is a task in the “Wait” state in the PDL task execution information. If there is a task in the “Wait” state, in step S1041, the page count page and the normal processing request message are transmitted to the task of the message transmission source. In step S1042, PageCount and “Exec” indicating that processing is being executed are set in the PDL task execution information.

  In step S1043, PageCount is incremented and a message reception is waited (step S1002). On the other hand, if there is no task in the “Wait” state, it waits for message reception (step S1002).

  If the received message is not a page processing notification, it is determined in step S1021 whether it is a job end notification. If it is a job processing notification, it is determined in step S1022 whether there is a task in the “Exec” state in the PDL task execution information. If there is a task in the “Exec” state, in step S1023, a message for requesting change to pipeline processing is transmitted to the task of the message transmission source. As a result, a free CPU can be used for object parallel execution by pipeline processing, and the processing time of the remaining unprocessed pages can be reduced. On the other hand, if there is no task in the “Exec” state, the PDL1 task and the PDL2 task are stopped in step S1024, and the processing of the PDL control unit is ended.

  FIG. 5 is a diagram illustrating an example of PDL task execution information managed by the PDL control unit 212 in the present embodiment.

  FIG. 5A shows the configuration of the PDL task execution information. The PDL task execution information includes a page number 501 and a task status 502. The page number 501 is the number of the page of each PDL task processing, processing, and processing end. The task status 502 indicates the processing status of each PDL task, and there are three statuses: processing waiting “Wait”, processing executing “Exec”, and processing end “End”.

  FIG. 5B shows PDL task execution information when the PDL task is activated. Both PDL task 1 and PDL task 2 are initialized to page number 0 and task status “End”.

  FIG. 5C shows PDL task execution information at the start of the first page. A page processing instruction request from the PDL task 1 is received, and the page number of the PDL task 1 is changed to 1, and the task status is changed to “Exec”.

  FIG. 5D shows the PDL task execution information at the start of the second page. The page processing instruction request from the PDL task 2 is received, and since the PDL task 1 is “Exec” while the first page is being processed, the page number of the PDL task 2 is changed to 2 and the task status is changed to “Wait”.

  FIG. 5E shows PDL task execution information at the end of the first page. A page processing end notification is received from the PDL task 1 and the task status of the PDL task 1 is changed to “End”. Further, since the PDL task 2 is in the “Wait” process waiting for the second page, the PDL task 2 is requested to process, and the task status of the PDL task 1 is changed to “Exec” while the process is being executed.

  FIG. 6 is a flowchart of processing executed by the CPU 204 by the PDL task 1 (402) and the PDL task 2 (403) in this embodiment.

  When the PDL tasks 1 and 2 are activated in step S1002 of the PDL control task 401, the PDL data passed from the reception unit 211 is read from the work memory 222 in step S1101, and a page processing instruction request is sent to the PDL control task 401. A message is transmitted, and a message reception waiting from the PDL control task 401 is awaited. When a processing request message is received, it is determined in step S1102 whether the received message is a pipeline processing request. In the case of a pipeline processing request, a pipeline task is activated in step S1103, and pipeline processing is executed in step S1104.

  When the processing of the pipeline processing page is completed, the pipeline task is stopped in step S1105. On the other hand, if the received message is a normal processing request, normal processing is executed in step S1106. Steps S1101 to S1107 are repeatedly executed until the job ends in steps S1104 and S1105.

  FIG. 7 is a flowchart illustrating the pipeline processing in step S1104 executed by the CPU 204 in this embodiment.

  In step S1201, when the PDL analysis unit 213 analyzes the PDL data, it is determined in step S1202 whether the page is finished. In the case of page end, a page processing end notification message is transmitted to the PDL control task 401 in step S1203. If it is not the end of the page, it is determined in step S1211 whether the job has ended. If the job has ended, a job end notification message is transmitted to the PDL control task 401 in step S1212. If the job is not finished, DL generation information is generated in step S1221, and the DL generation information is stored in the spool 302 via the spooler 301 in step S1222.

  In step S1223, a DL generation request message is transmitted to the pipeline task, and the analysis of the PDL data in S1201 is executed again.

  FIG. 8 is a diagram illustrating a flowchart of processing executed by the CPU 204 by the pipeline task in the present embodiment.

  When the pipeline task is started in step S1103 of the PDL task 1 or the PDL task 2, in step S1301, it waits for reception of a DL generation request message from the PDL task. When the DL generation request message is received, the DL generation information stored in the spooler 302 is read via the despooler 303 in step S1302, and the DL generation unit 214 generates DL in step S1303. In step S1304, the DL generation information is deleted from the spooler 302, and the process returns to message reception waiting in step S1301.

  FIG. 9 is a diagram illustrating a flowchart of normal processing in step S1105 executed by the CPU 204 in the present embodiment.

  When the PDL analysis unit 213 analyzes the PDL data in step S1401, it is determined in step S1402 whether the page is finished. In the case of page end, a page processing end notification message is transmitted to the PDL control task 401 in step S1403. If it is not the page end, it is determined in step S1411 whether the job is ended. If the job has ended, a job end notification message is transmitted to the PDL control task 401 in step S1412. If the job is not finished, DL generation information is generated in step S1421, DL is generated in the DL generation unit 214 in step S1422, and the PDL data analysis in S1201 is executed again.

101 Image forming apparatus 212 PDL control unit 213 PDL analysis unit 214 DL generation unit 215 Pipeline processing unit 216 Development processing unit 204 CPU
206 Printer engine

Claims (5)

With respect to PDL (Page Description Language) data, page parallel processing means (402, 403) for processing a plurality of pages in parallel by a plurality of PDL processes, and object parallel processing means (404 for processing objects in a page in parallel) 405) and a page determination unit (213) that analyzes PDL data and determines a page in an image forming apparatus (101) that executes the parallel processing unit by a plurality of CPUs (204).
Status management means (501, 502) for managing page processing statuses of a plurality of PDL processes executed by the page parallel processing means;
Depending on the page determination means and the status management means, the process switching means (S1003, S1022, S1103) for switching whether to execute the object parallel processing means, and the processing status managed by the status management means. An image forming apparatus comprising page processing control means (S1031, S1013) for switching the page processing execution of the page parallel processing. The image forming apparatus according to claim 1, wherein the object parallel processing unit performs parallel processing of PDL analysis and DL (Display List) generation in a pipeline in units of objects. 2. The image forming apparatus according to claim 1, wherein when the page determined by the page determination unit is determined to be a first page, the processing switching unit performs PDL processing of the page by the object parallel processing unit. The process switching means includes an end determination means for determining which one of the PDL processes has been completed from the statuses of the plurality of PDL processes managed by the status management means, and a PDL process completed by the end determination means. The image forming apparatus according to claim 1, wherein when there is an unfinished PDL process, the unfinished PDL process is switched to the object parallel processing unit to process the image forming apparatus. When the page processing control unit determines from the status of the plurality of PDL processes managed by the status management unit that the first page is being processed, the PDL process of the first page The image forming apparatus according to claim 1, wherein control is performed to wait until the process ends.