JP3978958B2 - Image forming apparatus - Google Patents

Description

BACKGROUND OF THE INVENTION
The present invention relates to an image forming apparatus, and more particularly, a method for reducing print processing time in an image forming apparatus capable of printing a plurality of sheets in one print engine cycle, and an image forming apparatus capable of executing the method. About.
[0001]
[Prior art]
Conventionally, in electrophotographic technology for obtaining a color image by superimposing a plurality of toner images of different colors, a color image forming apparatus for generating an image in which each color is once superimposed on an intermediate transfer member and transferring the image from the intermediate transfer member to a sheet Has been proposed. The intermediate transfer member of such an image forming apparatus often has an area equivalent to the maximum sheet size that can be printed by the image forming apparatus. Therefore, in some image forming apparatuses, when the area of the image that can be transferred to the intermediate transfer member is larger than the sheet to be printed and a plurality of pages of images can be transferred to the intermediate transfer member at the same time, a plurality of pages can be transferred. In some cases, a plurality of pages are printed at a high speed by generating a plurality of images on an intermediate transfer member at a time and sequentially transferring and transferring a plurality of sheets.
[0002]
For example, in a printer having a maximum printable paper size of A3, when printing a plurality of pages with a paper size of A4, one print engine cycle (image formation on an intermediate transfer member-image transfer onto paper) Then, two pages of images are formed on the intermediate transfer member, and two A4 sheets are sequentially transferred and transferred.
[0003]
In this way, the number of print engine cycles that take a relatively long time can be reduced to half of the number of printed sheets, and the time (throughput) required to execute (print processing) a print job can be shortened.
[0004]
[Problems to be solved by the invention]
However, if the printing process is performed according to the above procedure, the first print engine cycle cannot be started until the image generation process for two pages is completed, so the first print time (time until the first sheet is printed) There was a disadvantage that it became longer.
[0005]
Therefore, in the first print engine cycle, there is a method in which only one page is printed, and thereafter, a plurality of sheets are processed in one print engine cycle. However, in this case, the first print time may be short. However, depending on the number of printed sheets, it is necessary to process a useless print engine cycle, so that there is a disadvantage that throughput is deteriorated.
[0006]
For example, in the example of the printer having the maximum print size of A3, when printing 5 sheets of A4 paper, 1 sheet is printed in the first print engine cycle, and 2 sheets are printed in the second print engine cycle. The sheet will be printed. In this case, since the first print engine cycle can be started when the image generation process for one page is completed, two pages are printed in every print engine cycle, that is, two pages of images. Compared to the case where the first print engine cycle is started when the generation process is completed, the first print time can be shortened. Further, since the print engine cycle and the image generation processing for the second and subsequent pages can be executed in parallel, the overall throughput can be shortened.
[0007]
On the other hand, when printing 6 sheets of A4 paper, 1 sheet is printed in the first print engine cycle, 2 sheets are printed in the second, 3rd print engine cycle, and 1 sheet is printed in the fourth print engine cycle. However, in this case, since it is necessary to process the print engine cycle once more than when printing every two print engine cycles, the first print time is short, but the overall throughput is deteriorated. There were drawbacks.
[0008]
The present invention has been made to solve the above-described problems, and an object of the present invention is to provide an image forming apparatus capable of minimizing the overall throughput while minimizing the print engine cycle during the printing process.
[0009]
[Means for Solving the Problems]
  In order to solve the above problems, an image forming apparatus according to the present invention generates an image.Image generation processing, Print multiple sheets in one print engine cycle based on the generated imagePrinting process and,I doPrinting can be performed in one print engine cycle corresponding to the total number of prints of the image forming unit and the at least one print job specified by the image forming unit before generating the image and the print size specified by the print job Determining means for determining the number of prints in each print engine cycle of printing by the print job based on the maximum number of prints, and the image so that the number of prints determined by the determination means is printed in each print engine cycle Control means for controlling the forming means.
[0010]
According to the present invention, the number of prints in each print engine cycle is determined and printed based on the total number of print jobs and the maximum number of prints that can be printed in one print engine cycle. The number of prints in each print engine cycle can be determined so that the time required for the print job can be reduced, and the time required for the entire print job can be reduced.
[0011]
Note that “multiple sheets can be printed in one print engine cycle” does not necessarily mean that a plurality of sheets are printed in each printing process, but a plurality of sheets are printed in each printing process. If it is possible, it means that a plurality of printing processes can be performed. For example, if the maximum printable size is an A3 image forming apparatus, a plurality of sheets can be printed if the printing size is A4 or less. If the printing size exceeds A4, a plurality of sheets cannot be printed. It is meant to include devices.
[0012]
  Also,The determining means of the present invention is characterized in that the number of prints in the first print engine cycle of printing by the print job is determined so that a print processing time corresponding to the print job is shortened.The
[0013]
  The image forming unit executes the print processing of the generated image in parallel with the next image generation processing after the end of the image generation processing,The determining means determines the maximum number as the number of prints in the first print engine cycle of printing by the print job when the total number of prints is a multiple of the maximum number, and the total number of prints is the maximum number If it is not a multiple of the number of sheets, the remainder obtained by dividing the total number of printed sheets by the maximum number may be determined as the number of printed sheets in the first print engine cycle of printing by the print job. According to the present invention, since the number of prints in the first print engine cycle can be determined so as to reduce the number of print engine cycles, the print processing time corresponding to the print job can be shortened.
  In addition,When the next and subsequent print jobs after the rendering processing for converting the print job data into printable data by the engine are registered before the image generation for one print job is started, The total number of prints of the first print job and the next print job may be the total print number.
If the next next print job is additionally registered during the process for one print job, the print process for the first print job and the image generation process for the next print job are performed in parallel, and the decision is made. The means may determine the number of prints in the first print engine cycle of the next print job as the maximum print number that can be printed in one print engine cycle.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings.
[0015]
The image forming apparatus according to the present embodiment is a color laser printer. As shown in FIG. 1, a toner unit 10 having toners of four colors of cyan (C), magenta (M), yellow (Y), and black (K), and scanning for scanning a laser on a drum unit based on image data. Unit 12, drum unit 14 on which an electrostatic band image is formed by scanning unit 12, belt intermediate transfer body 16 that receives image transfer from drum unit 14, roller 22 for conveying paper 20, and toner on the paper And a fixing unit 24 for fixing.
[0016]
The image forming process by the image forming apparatus is performed in the following procedure. First, a cyan component electrostatic band image is formed on the drum unit 14 by the scanning unit 12, and then the toner unit 10 is rotated to generate a cyan component image on the drum unit 14 using cyan toner. The image generated on the drum unit 14 is transferred to the belt intermediate transfer member 16. Next, a magenta component image is similarly generated on the drum unit 14 and transferred onto the belt intermediate transfer member 12, and each image is transferred to the belt intermediate transfer member 16 in the same manner for the yellow component and the black component. In this way, four color images are synthesized on the belt intermediate transfer member 16. After the four color images are generated on the belt intermediate transfer body 16, the paper 20 is fed from the paper tray 18, and the image is transferred from the belt intermediate transfer body 16 to the paper 20 while being conveyed toward the discharge port 26 by the conveyance roller 22. After the image is transferred and the toner is fixed by the fixing unit 24, the paper is discharged from the discharge port 26. This series of processing is defined as one print engine cycle.
[0017]
In the image forming apparatus according to the present embodiment, the surface area of the belt intermediate transfer body 16 is the same as the area of the maximum printable paper size A3. Therefore, when the paper to be printed is A4, two pages of images can be generated on the belt intermediate transfer body 16 in one print engine cycle, and two sheets of paper 20 can be fed and transferred sequentially. Is possible.
[Number of prints in the first print engine cycle]
As described above, in an image forming apparatus capable of generating an image for a plurality of pages on the belt intermediate transfer member 16 and transferring it to a sheet in one print engine cycle, printing is performed in one print engine cycle. Depending on the number of pages, even for the same print job, the first print time (which means the time required to print the first page, hereinafter referred to as “FPOT”) and throughput (printing of all sheets in a series of prints) Means the time until completion). This will be described with reference to FIGS.
[0018]
FIG. 2 is a diagram for explaining the image generation processing time and the print processing time when the number of print jobs is a multiple of the number of pages that can be printed in one print engine cycle. Here, A4 size page printing is assumed, and two pages can be printed in one print engine cycle, and a total of four sheets are printed.
[0019]
When printing the number of pages that can be printed in one print engine cycle (for two pages) in the first print engine cycle, as shown in FIG. The print processing time for a page is FPOT. On the other hand, when only one page is printed in the first print engine cycle, as shown in FIG. 2B, the image generation processing time for one page plus the printing processing time for one page becomes FPOT. Therefore, FPOT is shorter when printing for one page in the first print engine cycle. However, regarding the throughput, when two pages are printed in the first print engine cycle (see FIG. 2A), the print processing can be performed in two print engine cycles, and image generation processing for two pages is possible. The sum of the print processing time for two pages, the print processing time for two pages (image generation for the second and third pages can be processed in parallel during the first print engine cycle) is the throughput. On the other hand, if one page is printed in the first print engine cycle (see FIG. 2B), three print engine cycles are required for the printing process for four sheets, and one page image is generated. Processing time, printing processing time for one page, time from the end of printing processing for the first page to the end of image generation for the third page (the image generation for the second and third pages is performed in parallel during the first print engine cycle) Although the processing is possible, the image generation processing end time of the third page is put ahead of the printing processing end time of the first page. The sum of the printing processing time for two pages and the printing processing time for one page Is the throughput. Therefore, the throughput is shorter when two pages are printed in the first print engine cycle. This indicates that since the time required for one print engine cycle is relatively long compared to the time required for image generation processing, the overall throughput is improved by reducing the number of print engine cycles. .
[0020]
FIG. 3 is a diagram illustrating image generation processing and print processing time when the number of print jobs is not a multiple of the number of pages that can be printed in one print engine cycle. Here, it is assumed that A4 size page printing is assumed in the same manner as described above, and that two pages can be printed in one print engine cycle, and a total of three sheets are printed.
[0021]
For FPOT, when only one page is printed in the first print engine cycle rather than printing the number of pages that can be printed in one print engine cycle (two pages) in the first print engine cycle This is the same as the case described above. However, regarding the throughput, when printing two pages in the first print engine cycle (see FIG. 3A), the image generation processing time for two pages, the printing processing time for two pages, and one page The sum of the print processing times is the throughput. On the other hand, when one page is printed in the first print engine cycle (see FIG. 3B), the image generation processing time for one page, the printing processing time for one page, and the printing processing for the first page are completed. The sum of the time from the start of image generation to the end of image generation for the third page and the print processing time for two pages is the throughput. In this case, both require two print engine cycles. However, when two pages are printed in the first print engine cycle, printing is performed between the image generation processes for the first and second pages. It is possible to perform only the image generation process for the third page in parallel with the first print engine cycle without starting the process. On the other hand, if only the first page is printed in the first print engine cycle, the first page print processing is performed immediately after the image generation processing for the first page. Some image generation processing can be performed in parallel with the first print engine cycle. Therefore, if only one sheet is printed in the first print engine cycle, the throughput is shortened by a part of the image generation processing time for the third page (see reference numeral 30 in FIG. 3B).
[0022]
Therefore, if the number of print jobs is a multiple of the number of pages that can be printed in one print engine cycle, the number of pages that can be printed in one print engine cycle in all print engine cycles If the number of print jobs is not a multiple of the number of pages that can be printed in one print engine cycle, the number of print jobs is divided by the number of pages that can be printed in one print engine cycle. It becomes clear that the throughput can be kept optimal by printing the excess number of sheets in the first print engine cycle. Therefore, in this embodiment, in order to keep the throughput optimal, when the number of print jobs is a multiple of the number of pages that can be printed in one print engine cycle, the print job is executed once in all print engine cycles. When printing is performed for the number of pages that can be printed in the print engine cycle, and the number of print jobs is not a multiple of the number of pages that can be printed in one print engine cycle, the number of print jobs is set to one print engine. The remainder of the number divided by the number of pages that can be printed in the cycle is printed in the first print engine cycle.
[0023]
If the number of print jobs is not a multiple of the number of pages that can be printed in one print engine cycle, the remainder of dividing the number of print jobs by the number of pages that can be printed in one print engine cycle. FPOT can also be improved by printing the number of sheets in the first print engine cycle.
[0024]
[About system configuration]
Next, the system configuration of the image forming apparatus in the present embodiment will be described. FIG. 4 is a block diagram showing a system configuration of the image forming apparatus according to the present embodiment. The printer controller 38 is connected to the host computer 40 and the engine controller 56, and the engine controller 56 is connected to the print engine 58. Inside the printer controller 38 are a communication I / F 42 that is a connection unit with the host computer 40, a PDL analysis unit 44 that performs analysis of the PDL language and registration of a print job from the host computer 40, and the number of prints to be registered. A registration unit 48, a drawing processing unit 46 for converting data from the PDL analysis unit 44 into data printable by the engine, and a scheduler 50 for registering a print schedule are arranged.
[0025]
When a print job is transmitted from the host computer 40 to the printer controller 38, the drawing process task shown in FIG. 5 and the scheduler task shown in FIG. 6 are executed in parallel.
[0026]
In the drawing processing task, in step 60, the PDL analysis unit 23 receives data from the host computer 40 via the communication I / F 42. In step 62, the PDL analysis unit 44 that has received the data registers a print job. This print job is put in the job queue 52 inside the scheduler task. In step 64, the print number registration unit 48 similarly registers the total number of prints of the print job received by the PDL analysis unit 44 in the job queue 52 in the scheduler task. It is assumed that the total number of sheets printed by the print job registered here is calculated on the host computer 40 when a printer driver (not shown) generates print job data. In step 66, the print job data from the host computer 40 is analyzed by the PDL analysis unit 44. The analyzed data is transmitted to the drawing processing unit 46, converted into data that can be printed by the engine in step 68, and this data is registered in the page queue 54 in the scheduler 50 for each page in step 70. Is done. In step 72, it is determined whether or not the print job is finished. If it is finished, this processing is finished. If the print job has not ended, the process returns to step 66 and the following processing is repeated. With this processing, necessary data is registered in the job queue 52 and the page queue 54.
[0027]
The scheduler task waits until a print job is registered in the job queue 52 in the scheduler 50 in step 76. If there is a registered print job, the number of prints of the registered print job is read, and it is determined in step 78 whether the number of prints is an odd number. If the number of printed sheets is an odd number, in step 80, the page queue 54 is read to determine whether the number of registered pages is one or more. That is, when the number of printed sheets is an odd number, if the number of sheets printed in the first print engine cycle is set to one page as described above, the throughput can be shortened. Therefore, registration of data for one page or more is completed. If the registration has been completed, a print engine cycle for image processing for one page is started in step 82. If it is determined in step 78 that the number of printed sheets is not an odd number, the page queue 54 is read in step 84 to determine whether the number of registered pages is two or more. In other words, when the number of printed sheets is an even number, if the number of sheets printed in the first print engine cycle is 2 pages, which is the maximum number of printable pages in one print engine cycle, the throughput can be shortened. It is determined whether or not the registration of the data has been completed. If the registration has been completed, a print engine cycle for image processing for two pages is started in step 86. In the second and subsequent print engine cycles, image processing is performed for two pages at a time. Therefore, in step 88, the page queue 54 is read to determine whether the number of registered pages is two pages or more. If registered, in step 90, a print engine cycle for image processing for two pages is started, and thereafter, step 88 and step 90 are repeated. If it is determined in step 88 that two or more pages are not registered, it is determined in step 92 whether or not the print job has been completed, that is, whether or not data for all pages of the print job has been transmitted. If NO in step 88, the flow returns to step 88 to wait until two or more pages are registered. If it is determined in step 92 that the print job is completed, the process returns to the initial state, that is, the first step 76, and the following processing is repeated.
[0028]
According to the present embodiment, when the number of prints of the entire print job is a multiple of the maximum number of prints that can be printed in one print engine cycle, in all print engine cycles including the first print engine cycle. The maximum number of pages that can be printed in one print engine cycle is set as the maximum number of pages to be printed, and the first print engine when the total number of print jobs is not a multiple of the maximum number of pages that can be printed in one print engine cycle The number of pages printed in a cycle is the remainder of the print job divided by the maximum number of prints that can be printed in a single print engine cycle, so throughput can be maintained optimally for image processing. The required time can be shortened. If the number of print jobs is not a multiple of the maximum number of prints that can be printed in one print engine cycle, the FPOT can be shortened.
[0029]
In the above-described embodiment, assuming that A4 paper is printed, the maximum number of printable sheets in one print engine cycle is set to two. However, the present invention is not limited to this. The same printing process can be performed when printing a sheet of paper.
[0030]
In this embodiment, the number of pages to be printed is determined in the first print engine cycle of the print job according to the number of prints for each print job. However, the drawing process is completed before starting image generation for one print job. If the subsequent print jobs are registered in the job queue 52, the number of pages to be printed in the first print engine cycle of the print job is determined in the same manner as described above according to the total number of print jobs of a plurality of print jobs. You can also For example, considering that the number of print jobs 1 is 3, and the number of print jobs 2 is 3, the print job 1 has 3 prints. Since it is a multiple of the maximum number of printable sheets (2) that can be printed in one print engine cycle, one sheet of print processing is performed in the first print engine cycle, but this requires four print engine cycles. (See FIG. 7B). Therefore, the number of pages to be printed in the first print engine cycle is determined based on the total number of print jobs (6) of print job 1 and print job 2. That is, since the number of printed sheets (6 sheets) is a multiple of the maximum number of printed sheets (2 sheets) that can be printed in one print engine cycle, as shown in FIG. By performing the printing process for the sheets, the print engine cycle can be made three times, and the throughput across the print jobs can be improved.
[0031]
If the next print job 2 is additionally registered during the processing of the print job 1, the print processing of the print job 1 and the image generation processing of the print job 2 are performed in parallel, and the print jobs are straddled. It is also possible to improve the throughput. In this case, the number of pages to be printed in the first print engine cycle of the print job 2 does not need to be the remaining number divided by the maximum number of prints that can be printed in one print engine cycle. If the maximum number of prints that can be printed in the print engine cycle is used, the throughput is minimized.
[0032]
【The invention's effect】
As described above, according to the present invention, the time required for the entire print job is reduced based on the total number of prints in at least one print job and the maximum number of prints that can be printed in one print engine cycle. Thus, since the number of prints in each print engine cycle is determined, the time required for the entire print job can be shortened.
[Brief description of the drawings]
FIG. 1 is a schematic diagram of an image forming apparatus according to an embodiment.
FIG. 2 is an explanatory diagram showing a processing time when a job for four pages is executed.
FIG. 3 is an explanatory diagram showing a processing time when a job for three pages is executed.
FIG. 4 is a block diagram showing a configuration of a system according to the present embodiment.
FIG. 5 is a diagram showing a flow of a drawing processing task according to the present embodiment.
FIG. 6 is a diagram showing a flow of a scheduler task according to the present embodiment.
FIG. 7 is an explanatory diagram showing processing times when two print jobs are executed.
[Explanation of symbols]
10 Toner unit
12 Scanning unit
14 drum units
16 Belt intermediate transfer member
18 Paper tray
20 paper
22 Roller
24 Fixing unit
26 Discharge port
38 Printer controller
40 Host computer
42 Communication I / F
44 PDL analyzer
46 Drawing processor
48 Number of copies printed
50 scheduler
52 Job queue
54 page queue
56 Engine controller
58 Print Engine

Claims (2)

Image forming means for performing image generation processing for generating an image, and printing processing for performing printing of a plurality of sheets in one print engine cycle based on the generated image;
The total number of prints of at least one print job specified before the image generation by the image forming unit and the maximum number of printable sheets in one print engine cycle corresponding to the print size specified by the print job A determination means for determining the number of prints in each print engine cycle of printing by the print job,
Control means for controlling the image forming means to print the number of printed sheets determined by the determining means in each print engine cycle;
With
The image forming unit executes a print process of the generated image in parallel with the next image generation process after the end of the image generation process,
The determining means determines the maximum number as the number of prints in the first print engine cycle of printing by the print job when the total number of prints is a multiple of the maximum number, and the total number of prints is the maximum number If it is not a multiple of the number of sheets, the remainder obtained by dividing the total number of printed sheets by the maximum number is determined as the number of printed sheets in the first print engine cycle of printing by the print job, and before image generation for one print job is started. If the next and subsequent next print jobs that have been subjected to the drawing process for converting the print job data into printable data by the engine are registered, the total number of prints of the first print job and the next print job An image forming apparatus , wherein the number of sheets is the total number of printed sheets . Image forming means for performing image generation processing for generating an image, and printing processing for performing printing of a plurality of sheets in one print engine cycle based on the generated image;
The total number of prints of at least one print job specified before the image generation by the image forming unit and the maximum number of printable sheets in one print engine cycle corresponding to the print size specified by the print job A determination means for determining the number of prints in each print engine cycle of printing by the print job,
Control means for controlling the image forming means to print the number of printed sheets determined by the determining means in each print engine cycle;
With
The image forming unit executes a print process of the generated image in parallel with the next image generation process after the image generation process is completed , and a next next print job is executed during the process for one print job. When additionally registered, the print processing of the first print job and the image generation processing of the next print job are performed in parallel,
The determining means determines the maximum number as the number of prints in the first print engine cycle of printing by the print job when the total number of prints is a multiple of the maximum number, and the total number of prints is the maximum number If it is not a multiple of the number of sheets, the remainder obtained by dividing the total number of printed sheets by the maximum number is determined as the number of printed sheets in the first print engine cycle of printing by the print job, and the image generation processing of the next print job is performed in parallel. In the case where it is performed, the number of prints in the first print engine cycle of the next print job is determined as the maximum number of prints that can be printed in one print engine cycle. .

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