JP2017121756A - Image formation apparatus - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform continuous printing of printing data described in the page description language without delay.SOLUTION: An image formation apparatus 1 includes: a page unit division part 101; an interpreter part 102; a rasterizer part 103; and a control part 100 which causes a printing part to print a raster image of the generated previous page while causing the interpreter part 102 and rasterizer part 103 to process the page data of the next page and generate the raster image in the printing order of the plurality of pieces of page data. The control part 100 predicts the processing time in the rasterizer part 103 for each page data, and causes a plurality of processor cores to perform raster image generation processing of the page data by allocating the plurality of processor cores to the rasterizer part 103 when it is determined that generation of the raster image becomes too late to the printing timing of the raster image for one page data.SELECTED DRAWING: Figure 2

Description

  The present invention relates to an image forming apparatus, and more particularly to a technique for continuously printing print data described in a page description language without delay.

  In recent years, many image forming apparatuses are equipped with a RIP (Raster Image Processor) that develops print data described in a page description language into a raster image. Patent Document 1 below processes a large number of jobs at high speed by dividing a job into a plurality of pages and executing a plurality of divided jobs with a plurality of RIPs when the job processing is high-speed processing. Technology is disclosed.

JP 2001-134389 A

  In order to continuously print the print data described in the page description language without delay, it is only necessary to start printing after generating raster images of all pages. However, in this method, printing is not started until the generation of the raster image for all pages is completed. Therefore, when the number of pages is large, a very long waiting time is generated until printing is started. On the other hand, it is conceivable that the raster image of each page is sequentially printed while generating the raster image of each page. May occur, and it may take time to resume printing. In this regard, further improvement is expected.

  SUMMARY An advantage of some aspects of the invention is that print data described in a page description language can be continuously printed in a shorter time without any delay.

An image forming apparatus according to an aspect of the present invention includes a page unit dividing unit that divides print data described in a page description language into a plurality of page data in page units,
An interpreter for converting a page description language in the page data into an intermediate language;
A raster riser unit that processes the page data converted into the intermediate language to generate a raster image;
An image memory for temporarily storing the raster image;
A printing unit for printing the raster image on paper;
The previous page generated from the image memory while writing the raster image generated by causing the interpreter unit and the raster riser unit to process the page data of the next page in the printing order of the plurality of page data. A control unit that reads the raster image of the image and prints it on the printing unit,
The controller is
When the processing time in the raster riser unit and the printing timing of the raster image are predicted for each page data, and it is determined that the generation of the raster image is not in time by the printing timing of the raster image for a certain page data, the raster riser A plurality of processor cores are allocated to the unit, and at least raster image generation processing of the page data is performed by the plurality of processor cores.

  According to the present invention, print data described in a page description language can be continuously printed in a shorter time without delay.

1 is a front sectional view showing a structure of an image forming apparatus according to an embodiment of the present invention. 2 is a functional block diagram illustrating a main internal configuration of the image forming apparatus. FIG. 6 is a flowchart illustrating a printing process of print data described in a page description language in the image forming apparatus. 6 is a timing chart of raster image generation and printing when PDL print data is processed by only one core. 6 is a timing chart of raster image generation and printing when PDL print data is processed by a plurality of cores.

  Hereinafter, an image forming apparatus according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a front sectional view showing the structure of an image forming apparatus according to an embodiment of the present invention.

  An image forming apparatus 1 according to an embodiment of the present invention is a multifunction machine having a plurality of functions such as a copy function, a printer function, a scanner function, and a facsimile function. The image forming apparatus 1 includes an apparatus main body 11 that includes an operation unit 47, an image forming unit 12, a fixing unit 13, a paper feeding unit 14, a document feeding unit 6, a document reading unit 5, and the like.

  The operation unit 47 receives instructions such as an image forming operation execution instruction and a document reading operation execution instruction from the operator regarding various operations and processes that can be executed by the image forming apparatus 1. The operation unit 47 includes a display unit 473 that displays operation guidance to the operator. The display unit 473 is a touch panel, and an operator can operate the image forming apparatus 1 by touching a key displayed on the screen.

  When the image forming apparatus 1 performs a document reading operation, the document reading unit 5 optically reads a document fed by the document feeding unit 6 or a document placed on the document placing glass 161, Generate image data. Image data generated by the document reading unit 5 is stored in a built-in HDD or a network-connected computer.

  When the image forming apparatus 1 performs an image forming operation, it is based on image data generated by the document reading operation, image data received from a computer connected to a network, image data stored in a built-in HDD, or the like. Then, the image forming unit 12 forms a toner image on a sheet P as a recording medium fed from the sheet feeding unit 14. When performing color printing, the magenta image forming unit 12M, the cyan image forming unit 12C, the yellow image forming unit 12Y, and the black image forming unit 12Bk of the image forming unit 12 respectively A toner image is formed on the photosensitive drum 121 by charging, exposure, and development processes based on an image composed of each color component constituting data, and the toner image is formed on the intermediate transfer belt 125 by the primary transfer roller 126. Let them transcribe.

  The toner images of the respective colors transferred onto the intermediate transfer belt 125 are superimposed on the intermediate transfer belt 125 with the transfer timing adjusted to form a color toner image. The secondary transfer roller 210 passes the toner image of the color formed on the surface of the intermediate transfer belt 125 from the paper supply unit 14 through the conveyance path 190 at a nip N between the intermediate transfer belt 125 and the driving roller 125a. Transfer is performed on the conveyed paper P. Thereafter, the fixing unit 13 fixes the toner image on the paper P to the paper P by thermocompression bonding. The sheet P on which the color image has been formed after the fixing process is completed is discharged to the discharge tray 151.

  The paper feed unit 14 includes a manual feed tray 141 and a plurality of paper feed cassettes. When the size of the paper is designated by the operator, the pickup roller 145 of the paper feed cassette containing the paper of that size is driven to rotate, and the paper P contained in each paper feed cassette is fed to the nip portion N. Transport toward.

  In the image forming apparatus 1, when performing double-sided printing, the sheet P on which an image is formed on one side by the image forming unit 12 is nipped by the discharge roller pair 159, and then the sheet P is loaded. The sheet is switched back by the discharge roller pair 159 and sent to the reverse conveyance path 195, and is conveyed again to the upstream area in the conveyance direction of the paper P with respect to the nip portion N and the fixing unit 13 by the conveyance roller pair 19. As a result, an image is formed on the other side of the sheet by the image forming unit 12.

  In the image forming apparatus 1 configured as described above, a portion including the image forming unit 12, the fixing unit 13, the paper feeding unit 14, the conveyance path 190, and the reverse conveyance path 195 corresponds to a printing unit in the claims.

  FIG. 2 is a functional block diagram showing the main internal configuration of the image forming apparatus 1. The image forming apparatus 1 includes a control unit 10, an operation unit 47, a document feeding unit 6, a document reading unit 5, an image memory 32, an image forming unit 12, a fixing unit 13, a drive motor 70, a facsimile communication unit 71, and a network interface unit. 91, HDD 92, and the like.

  The document reading unit 5 includes a reading mechanism 163 (FIG. 1) having a light irradiation unit, a CCD sensor, and the like under the control of the control unit 10. The document reading unit 5 reads an image from the document by irradiating the document with the light irradiating unit and receiving the reflected light with a CCD sensor.

  The image memory 32 is an area for temporarily storing document image data obtained by reading by the document reading unit 5 and temporarily storing data to be printed by the image forming unit 12.

  The HDD 92 is a large-capacity storage device that stores document images and the like read by the document reading unit 5.

  The facsimile communication unit 71 includes an unillustrated encoding / decoding unit, modulation / demodulation unit, and NCU (Network Control Unit), and performs facsimile transmission using a public telephone network.

  The network interface unit 91 includes a communication module such as a LAN board, and transmits and receives various data to and from the local area or the computer 20 on the Internet via a LAN connected to the network interface unit 91.

  A computer 20 is connected to the image forming apparatus 1. A printer driver for the image forming apparatus 1 is installed in the computer 20. When the computer 20 prints an image created by a word processor, CAD (Computer Aided Design), graphic software, or the like using the image forming apparatus 1, the printer driver posts the contour and fill information of each graphic element included in the image. It is described in a page description language (PDL) such as a script (registered trademark), pre-scribe (registered trademark), or PCL6, and print data is generated and transmitted to the image forming apparatus 1.

  The network interface unit 91 receives print data (hereinafter referred to as PDL print data) described in a page description language transmitted from the computer 20 and stores it in the HDD 92 as a print job.

  The driving motor 70 is a driving source that applies a rotational driving force to each rotating member of the image forming unit 12, the conveyance roller pair 19, and the like.

  The control unit 10 includes a CPU (Central Processing Unit), a RAM, a ROM, a dedicated hardware circuit, and the like, and controls overall operation of the image forming apparatus 1. The control unit 10 includes a control unit 100, a page unit dividing unit 101, an interpreter unit 102, and a raster riser unit 103.

  The control unit 100 includes an operation unit 47, a document feeding unit 6, a document reading unit 5, an image memory 32, an image forming unit 12, a fixing unit 13, a drive motor 70, a facsimile communication unit 71, a network interface unit 91, an HDD 92, and the like. And control each of these parts.

  For example, when the control unit 100 receives a print job from the computer 20, when the print job includes PDL print data, the page unit division unit 101, the interpreter unit 102, and the rasterizer unit 103 perform the PDL print data. Then, each process for generating a bitmap image (raster image) corresponding to the output resolution (for example, 600 dpi) of the image forming apparatus 1 is performed. For example, the control unit 100, the page unit dividing unit 101, the interpreter unit 102, and the rasterizer unit 103 have a function as RIP. Details of processing by the control unit 100 will be described later.

  The page unit dividing unit 101 divides PDL print data into a plurality of page data in page units. For example, the page unit dividing unit 101 can divide the PDL print data into a plurality of page data in page units by searching for escape sequences or page break commands representing page breaks in the PDL print data.

  The interpreter unit 102 converts the page description language in the page data into an intermediate language such as DL (Display List). By the conversion process in the interpreter unit 102, the page data is represented as a set of commands for generating graphic elements such as images, texts, and fills that can be processed by the rasterizer unit 103.

  The rasterizer unit 103 processes the page data converted into the intermediate language to generate a raster image. Specifically, in accordance with the command included in the page data, the rasterizer unit 103 displays the graphic element having the contour, the fill, and the size indicated by the command at a position indicated by the command in a predetermined drawing area. Drawing (rendering process). By executing all the commands included in the page data in this way, one raster image in which a plurality of graphic elements are collected is generated. The raster riser unit 103 stores the generated raster image in the image memory 32.

  In the present embodiment, the control unit 10 functions as the control unit 100, the page unit dividing unit 101, the interpreter unit 102, and the rasterizer unit 103 by an operation according to a computer program installed in the HDD 92. However, the control unit 100, the page unit dividing unit 101, the interpreter unit 102, and the rasterizer unit 103 can be configured by hardware circuits regardless of the operation of the control unit 10 according to the computer program.

  Next, PDL print data print processing in the image forming apparatus 1 will be described. FIG. 3 is a flowchart illustrating the PDL print data printing process in the image forming apparatus 1.

  First, the control unit 100 reads PDL print data from a print job received from the computer 20 and passes it to the interpreter unit 101. The interpreter unit 101 divides the delivered PDL print data into a plurality of page data in page units (S1).

  The control unit 100 determines the printing order of each page data according to the printing conditions of the PDL print data (S2). For example, when the printing condition is single-side face-down paper discharge (printing an image on one side of the paper and discharging the paper to the discharge tray 151 with the print side down), the printing order is ascending from one page. When the printing condition is single-sided face-up discharge (printing an image on one side of the paper and discharging the paper to the discharge tray 151 with the print side up), the printing order is descending from the last page. On the other hand, when the printing condition includes both sides, the printing order is not limited to this. For example, when printing by double-sided face-down paper discharge, the first page → the third page → the fifth on the surface of a plurality of sheets (for example, three sheets) of paper P continuously fed from the paper supply unit 14 to the image forming unit 12. The pages are printed in order, and then these three sheets P are switched back and conveyed again to the image forming unit 12, and the second page, the fourth page, and the sixth page are printed in order on the back surface. That is, the printing order when printing by double-sided face-down paper discharge is as follows: first page → third page → fifth page → second page → fourth page → sixth page.

  Next, the control unit 100 predicts the processing time in the rasterizer unit 103 for each page data of the PDL print data (S3). In the process of generating a raster image from page data, the process that requires the most calculation load is a rendering process in the raster riser unit 103. Therefore, the control unit 100 predicts the processing time in the raster riser unit 103 for each page data of the PDL print data, and if the generation of the raster image is not in time by the printing timing of the raster image for a certain page data. When the determination is made, a plurality of processor cores are allocated to the raster riser unit 103 to speed up the rendering process.

  Here, the control unit 100 can predict the processing time in the rasterizer unit 103 based on the presence or absence of a predetermined command in the page data. The command is, for example, a gradation processing command, a transparent composition processing command, or the like. Since these commands are commands that are particularly computationally intensive in the rendering process, it is considered that it takes a relatively long processing time to generate a raster image of page data including these commands.

  Furthermore, the control unit 100 may predict the processing time in consideration of the area of an object such as a character, a figure, a picture, or a table generated by the command. Since the calculation load is heavier as the area of the object is larger, a longer processing time is required. Therefore, by using the area of the object generated by the above command (for example, a predetermined processing time per unit area is determined and used), a more accurate processing time in the raster riser unit 103 can be obtained. Can be predicted.

  The control unit 100 stores the time required for processing the page data including the command in the rasterizer unit 103, and predicts the processing time in the rasterizer unit 103 for similar page data. The processing time of the same page data may be predicted with reference to the stored processing time. That is, the control unit 100 stores the time required for processing the page data including the command in the raster riser unit 103, and similarly processing time in the raster riser unit 13 for other page data including the command. Is predicted, the processing time of the other page data is predicted using the stored processing time. According to this, it is possible to predict the processing time in the raster riser unit 103 more accurately.

  When the control unit 100 predicts the processing time in the rasterizer unit 103 for each page data of the PDL print data, it passes the page data of the first page to the interpreter unit 102. The interpreter unit 102 converts the PDL of the page data of the first page into DL. The rasterizer unit 103 receives page data from the interpreter unit 102, creates a raster image for the first page according to the DL in the page data, and stores the raster image in the image memory 32 (S4).

  Note that the printing of the first page may be started after the raster image of the first page is generated. Therefore, the raster image of the first page does not need to be processed at high speed. In the raster image generation, only one processor core may be allocated to the raster riser unit 103.

  When the generation of the raster image of the first page is finished, the control unit 100 is necessary for the raster riser unit 103 to generate the raster image of the next page based on the processing time in the raster riser unit 103 predicted in step S3. A large number of processor cores are allocated (S5). Then, the control unit 103 writes the raster image generated by causing the interpreter unit 102 and the rasterizer unit 103 to process the page data of the next page in the printing order of the plurality of page data, while writing to the image memory 32. Then, the generated raster image of the previous page is read out, and the image forming unit 12 and the fixing unit 13 are controlled to print the raster image on the paper P (S6).

  In step S5, the necessary number of processor cores are allocated to the raster riser unit 103 as follows. The control unit 100 calculates the printing timing for the second and subsequent pages of the PDL print data according to the continuous printing speed (for example, 24 sheets / minute) of the image forming apparatus 1. Then, the control unit 100 compares the processing time in the raster riser unit 103 for each previously predicted page data with the printing timing of each page, and the raster data for a certain page data by the printing timing of the raster image. When it is determined that the image generation is not in time, a plurality of processor cores are assigned to the raster riser unit 103, and the raster image generation processing of the page data is performed by the plurality of processor cores.

  Furthermore, when the printing operation in the image forming unit 12 and the fixing unit 13 is temporarily stopped due to a paper jam or the like, the control unit 100 performs processing in the raster riser unit 103 that has predicted the remaining page data in which the raster image has not been generated. Processor cores may be reassigned to the raster riser unit 103 based on time. Thus, when the paper jam is resolved and printing is resumed, the remaining pages can be continuously printed without delay.

  A plurality of processor cores may be assigned to the rasterizer unit 103 and a plurality of page data may be simultaneously processed by the plurality of processor cores. FIG. 4 is a timing chart of raster image generation and printing when PDL print data is processed by only one core. FIG. 5 is a timing chart of raster image generation and printing when PDL print data is processed by a plurality of cores. In any timing chart, page data for 6 pages is included in the PDL print data, and double-sided face-down paper discharge is selected (that is, first page → third page → fifth page → second page → second page). It is assumed that it takes a relatively long time to generate the raster image of the second page.

  When printing PDL print data with only one core (FIG. 4), printing proceeds smoothly from the first page to the third page to the fifth page, but it takes time to generate the raster image of the second page, Immediately after the printing of the fifth page, the raster image of the second page has not yet been generated, and printing is paused until a raster image of the second page is generated, resulting in a waiting time.

  On the other hand, the control unit 100 determines that the raster image generation is not in time for the page data of the second page by the printing timing of the raster image at the start of processing of the PDL print data, and the raster riser unit 103. A plurality of processor cores can be assigned to a plurality of page data to be simultaneously processed by each processor core. For example, as illustrated in FIG. 5, the control unit 100 allocates two processor cores to the raster riser unit 103, and raster images of the first page, the third page, the fourth page, and the sixth page are assigned to the processor core 0. And the processor core 1 generates raster images of the fifth page and the second page. In addition, for example, it is also possible to cause the processor core 0 to generate raster images of the first page, the third page, the fifth page, the fourth page, and the sixth page, and to cause the processor core 1 to generate the second page. It is.

  Thus, unlike the case of FIG. 4, since the raster image of the second page has already been generated immediately after the printing of the fifth page, the second page can be printed following the printing of the fifth page. , All pages of the PDL print data can be continuously printed without delay.

  Returning to FIG. 3, after step S <b> 6, the control unit 100 confirms whether or not the last page raster image has been generated. If not (NO in S <b> 7), the control unit 100 returns to step S <b> 5 and the next page raster. A necessary number of processor cores are allocated to the raster riser unit 103 for image generation. On the other hand, if the raster image of the final page has been generated (YES in S7), the control unit 100 reads the raster image of the next page from the image memory 32 and controls the image generation unit 12 and the fixing unit 13 to control the raster. The image is printed on the paper P (S8).

  Thereafter, the control unit 100 confirms whether or not the printing of the raster image of the last page has been completed. If not (NO in S9), the control unit 100 returns to step S8 and prints the raster image of the next page. On the other hand, if the printing of the raster image of the last page is finished (YES in S9), the printing process of the PDL print data is finished.

  As described above, according to the present embodiment, the processing time of each page data of the PDL print data is predicted and the required number of processor cores are allocated to the rasterizer unit 103, so that the PDL print data can be continuously transmitted without delay. Can be printed.

  The present invention is not limited to the configuration of the above embodiment, and various modifications can be made. For example, in the above-described embodiment, a multifunction peripheral is used as an embodiment of the image forming apparatus according to the present invention. However, this is merely an example, and another image forming apparatus such as a printer may be used.

  Moreover, in the said embodiment, the structure and process which were shown by the said embodiment using FIG. 1 thru | or FIG. 5 are only one Embodiment of this invention, and are not the meaning which limits this invention to the said structure and process.

1 Image forming apparatus 12 Image forming unit (printing unit)
13 Fixing part (printing part)
32 Image memory 100 Control unit 101 Page unit division unit 102 Interpreter unit 103 Raster riser unit

Claims (7)

A page unit dividing unit that divides print data described in a page description language into a plurality of page data in page units;
An interpreter for converting a page description language in the page data into an intermediate language;
A raster riser unit that processes the page data converted into the intermediate language to generate a raster image;
An image memory for temporarily storing the raster image;
A printing unit for printing the raster image on paper;
The previous page generated from the image memory while writing the raster image generated by causing the interpreter unit and the raster riser unit to process the page data of the next page in the printing order of the plurality of page data. A control unit that reads the raster image of the image and prints it on the printing unit,
The controller is
When the processing time in the raster riser unit and the printing timing of the raster image are predicted for each page data, and it is determined that the generation of the raster image is not in time by the printing timing of the raster image for a certain page data, the raster riser An image forming apparatus in which a plurality of processor cores are allocated to a unit and at least raster image generation processing of the page data is performed by the plurality of processor cores. The controller is
When it is determined that the generation of the raster image is not in time for the print timing of the raster image for a certain page data, a plurality of processor cores are allocated to the raster riser unit and a plurality of page data is processed simultaneously by each processor core. Item 2. The image forming apparatus according to Item 1. The controller is
When the printing operation of the printing unit is temporarily stopped, a processor core is allocated to the raster riser unit based on the processing time in the raster riser unit that has been predicted for the remaining page data in which the raster image has not been generated. The image forming apparatus according to claim 1 or claim 2 to be corrected. The controller is
The image forming apparatus according to claim 1, wherein a processing time in the rasterizer unit is predicted based on whether or not a predetermined command is included in each page data. The controller is
The image forming apparatus according to claim 4, wherein the processing time is predicted based on an area of an object generated by the predetermined command.   The image forming apparatus according to claim 4, wherein the predetermined command includes at least one of a gradation processing command and a transparent composition processing command. The controller is
The time required for processing the page data including the predetermined command in the raster riser unit is stored, and similarly the processing in the raster riser unit for other page data including the predetermined command is stored. The image forming apparatus according to claim 4, wherein when the time is predicted, the processing time of the other page data is predicted using the stored processing time.