Image forming apparatus, image forming method, image forming system and program

Abstract

To provide an image forming apparatus that can improve printing efficiency.SOLUTION: An image forming apparatus includes: a buffer unit that stacks a plurality of sheets, each sheet having been printed and to be applied with post-processing based on a first print job, and transmits a stop signal instructing to stop the first print job when the plurality of sheets are fully stacked on the buffer unit; a first ejection unit that ejects the sheet having been printed and applied with the post-processing based on the first print job; a second ejection unit that ejects the sheet having been printed based on a second print job, the second print job being executed after the first print job is stopped upon reception of the stop signal; a calculation unit that calculates a predicted printing time required for printing for each print job based on printing capability, and calculates a predicted post-processing time required for post-processing for each print job based on post-processing capability; and a selection unit that selects the print job being the second print job from the plurality of print jobs based on the predicted printing time and the predicted post-processing time.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to an image forming apparatus, an image forming method, an image forming system, and a program. [Background technology]

[0002] There is a known technology for providing a buffer in an image forming device to compensate for differences in processing speed with a connected post-processing device. Patent Document 1 discloses a technology related to a printing device that accepts input of multiple jobs, processes them in parallel, associates the paper on which each page is printed with one of multiple paper output trays to be output to, and accumulates the pages for each paper output tray in a page queue waiting to be output. Summary of the Invention [Problem to be solved by the invention]

[0003] When an accepted job is associated with a paper output tray, if the associated tray is in use and not available, a print wait occurs, which may result in a decrease in printing efficiency.

[0004] SUMMARY OF THE INVENTION In order to solve the above problems, an object of the present invention is to provide an image forming apparatus that improves printing efficiency. [Means for solving the problem]

[0005] An image forming device according to one aspect of the present invention includes a buffer unit that stacks sheets printed by a first print job before post-processing and sends a stop signal to stop the first print job when the buffer is full of sheets; a first discharge unit that discharges the sheets printed by the first print job after post-processing; a second discharge unit that discharges the sheets printed by a second print job that begins execution after the first print job is stopped upon receiving the stop signal; a calculation unit that calculates an estimated printing time required for printing for each print job based on printing performance and an estimated post-processing time required for post-processing for each print job based on post-processing performance; and a selection unit that selects a print job to be the second print job from a plurality of the print jobs based on the estimated printing time and the estimated post-processing time. [Effects of the Invention]

[0006] According to the image forming apparatus of the present invention, printing efficiency can be improved. [Brief explanation of the drawings]

[0007] [Figure 1] 1 is a schematic diagram of an overall configuration of an image forming apparatus according to an embodiment of the present invention; [Figure 2] 1 is a diagram illustrating a hardware configuration of an image forming apparatus according to an embodiment of the present invention. [Figure 3] 1 is a functional block diagram of an image forming apparatus according to an embodiment of the present invention; [Figure 4] 10A and 10B are diagrams illustrating an example of a sheet on which job information is printed and which is discharged by an image forming apparatus according to an embodiment of the present invention. [Figure 5] FIG. 2 is a flowchart illustrating an image forming method executed by the image forming apparatus according to an embodiment of the present invention. [Figure 6] 10A and 10B are diagrams for explaining the relationship between the progress of each print job, the post-processing speed, and the printing speed in an image forming apparatus according to an embodiment of the present invention. [Figure 7] FIG. 1 is a diagram illustrating a first embodiment of an image forming apparatus according to an embodiment of the present invention. [Figure 8] FIG. 10 is a diagram illustrating Example 2 of an image forming apparatus according to an embodiment of the present invention. [Figure 9] FIG. 10 is a diagram illustrating Example 3 of an image forming apparatus according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0008] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The following describes the preferred embodiments of the present invention with reference to the accompanying drawings. In the drawings, the same components are designated by the same reference numerals, and redundant explanations may be omitted.

[0009] [Embodiment] <Configuration of Image Forming Apparatus 1> 1 is a schematic diagram of the overall configuration of an image forming apparatus 1 according to one embodiment of the present invention. The image forming apparatus 1 may be, for example, an MFP (Multifunction Peripheral) including functions such as a printer, copy machine, and facsimile machine, or an electronic device including an image forming function such as a printer.

[0010] Image forming apparatus 1 includes image forming unit 10, conveying unit 20, post-processing mechanism 30, first discharge unit 41, and second discharge unit 42. Second discharge unit 42 may be included in conveying unit 20. Arrows in the diagram indicate the flow of sheets P. In the following, a print job in which printed sheets P are subjected to post-processing and discharged to first discharge unit 41 will be referred to as a first print job, and a print job in which printed sheets P are discharged to second discharge unit 42 will be referred to as a second print job. Arrow F1 in the diagram indicates the flow of sheets P printed by the first print job. Arrow F2 in the diagram indicates the flow of sheets P printed by the second print job.

[0011] The image forming unit 10 includes a paper feed tray 11. The image forming unit 10 performs printing for each print job on a sheet P supplied from the paper feed tray 11. The sheet P is transported in the direction indicated by the arrow in the figure. An example of the sheet P is printing paper, but is not limited to this.

[0012] The conveying unit 20 conveys the sheet P printed by the first print job to the post-processing mechanism 30. The post-processing mechanism 30 includes a post-processing unit 31 and a buffer unit 32. The post-processing mechanism 30 is provided downstream of the image forming unit 10, and performs post-processing on the printed sheet P.

[0013] The post-processing performed by the post-processing unit 31 includes an alignment process for aligning the edges of the sheets P, a folding process for forming creases in the sheets P, a binding process for binding a stack of the sheets P with their edges aligned, and a saddle stitching process for folding the sheets P in half and binding them at the crease position. The sheets P discharged to the second discharge unit 42 may be manually moved to the post-processing mechanism 30 and post-processed.

[0014] The buffer unit 32 stacks sheets P that have been printed by the first print job and have not yet been subjected to post-processing, since it is necessary to prevent sheets P from becoming stuck on the discharge path due to the difference between the post-processing speed by the post-processing unit 31 and the printing speed by the image forming unit 10.

[0015] When the buffer unit 32 is full of sheets P, it sends a stop signal to stop the first print job. When the image forming unit 10 receives the stop signal, it stops the first print job. When the first print job stops, printing by the second print job starts.

[0016] The first discharge section 41 discharges sheets P that have been printed by a first print job and have undergone post-processing. The second discharge section 42 discharges sheets P that have been printed by a second print job that starts execution after the first print job is stopped upon receipt of a stop signal.

[0017] 2 is a diagram showing the hardware configuration of an image forming apparatus 1 according to an embodiment of the present invention. The image forming apparatus 1 includes a CPU (Central Processing Unit) 51, a ROM (Read Only Memory) 52, a RAM (Random Access Memory) 53, an HDD (Hard Disk Drive) 54, and an input / output I / F (Interface) 55. These components are electrically connected to one another via a bus 59.

[0018] The CPU 51 controls the operation of the image forming apparatus 1. The ROM 52 stores programs and the like executed by the CPU 51. The RAM 53 is used as a work area for the CPU 51. The HDD 54 stores various data such as programs. The input / output I / F 55 is an interface for inputting and outputting various signals and data to and from external devices.

[0019] Some or all of the functions of the CPU 51 may be realized by an electronic circuit such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field-Programmable Gate Array).

[0020] <Background of the study leading to the idea of ​​the image forming apparatus 1 according to the embodiment> Here, the details of the investigations that led to the idea of ​​the image forming apparatus 1 according to the embodiment will be described.

[0021] By providing the buffer unit 32, printing of a print job can be executed intermittently even if there is a difference between the printing speed and the post-processing speed of the post-processing unit 31. However, when the buffer unit 32 sends a stop signal, the image forming unit 10 that receives the stop signal temporarily stops printing, which reduces printing efficiency.

[0022] Even if the capacity of the buffer unit 32 is increased, it may become full with sheets P, causing printing to be temporarily stopped. Furthermore, for an ongoing print job, if the buffer unit 32 becomes full with sheets P and the sheets P are discharged to the second discharge unit 42, the sheets P printed in one print job will be discharged separately. This requires the work of combining the discharged sheets P in a dispersed manner.

[0023] Furthermore, if printing by another print job starts while printing by the currently running print job is temporarily stopped by a stop signal, the order in which sheets P are discharged may differ from the order in which the accepted print jobs were printed. Furthermore, it may be preferable to give priority to jobs that use the post-processing unit 31 and to reduce the time that the post-processing unit 31 is not operating.

[0024] This led to the development of the image forming apparatus 1 according to this embodiment. Below, functional blocks of the image forming apparatus 1 according to one embodiment of the present invention will be described.

[0025] 3 is a functional block diagram of an image forming apparatus 1 according to an embodiment of the present invention. The image forming apparatus 1 includes a data input unit 2, an image development unit 3, a printing unit 4, a paper feed / discharge unit 5, a display / operation unit 6, a calculation unit 7, a selection unit 8, and a control unit 9.

[0026] The data input unit 2 accepts input of a print job. The image processing unit 3 performs processing such as converting the format of image data into a format that can be processed later. Specifically, the image processing unit 3 converts the image data into pixel data for black, magenta, cyan, and yellow.

[0027] The printing unit 4 prints on sheets P according to a print job. The paper feed / discharge unit 5 feeds sheets P from a paper feed tray 11 to a paper feed path. The paper feed / discharge unit 5 also transports printed sheets P to a first discharge unit 41 or a second discharge unit 42. The display / operation unit 6 is an operation panel or the like having a display unit, and displays operations for the image forming apparatus 1, the status of the apparatus, the progress of processing, etc.

[0028] The calculation unit 7 calculates the estimated printing time required for printing each print job based on the printing performance of the image forming apparatus 1. The calculation unit 7 also calculates the estimated post-processing time required for post-processing each print job based on the post-processing performance of the image forming apparatus 1.

[0029] The calculation unit 7 calculates a print pause time, which is the time for which the first print job is stopped by a pause signal. The print pause time is the time obtained by subtracting the estimated print time from the estimated post-processing time. The calculation unit 7 also calculates a cumulative print pause time, which is the cumulative total of the print pause times of multiple first print jobs.

[0030] In this way, the calculation unit 7 calculates processing time information for each print job, including the estimated printing time, estimated post-processing time, print pause time, and cumulative print pause time.

[0031] The selection unit 8 selects a print job to be the second print job from the plurality of print jobs based on the estimated print time and the estimated post-processing time. More specifically, the selection unit 8 selects a print job to be the second print job by comparing the estimated print time and the cumulative print pause time.

[0032] More specifically, the selection unit 8 assumes that the estimated printing time of the first print job is equal to or greater than the cumulative print pause time of the first print job accepted immediately before the first print job, and selects the first print job as the second print job if the estimated printing time of the first print job is less than the cumulative print pause time of the first print job accepted immediately after the first print job, excluding the print pause time of the first print job.

[0033] By selecting the second job in this way, the selection unit 8 can give priority to printing by the first print job that will undergo post-processing, and can complete printing in the order of the accepted print jobs.

[0034] The control unit 9 controls the overall operation of the image forming apparatus 1. The control unit 9 causes the image forming unit 10 to execute printing according to the first print job. The control unit 9 also controls the path for discharging the sheets P printed by the first print job and the second print job.

[0035] 4 is a diagram showing an example of a sheet on which job information is printed, which is discharged by the image forming apparatus 1 according to one embodiment of the present invention. After printing by a series of print jobs is completed, the image forming apparatus 1 may discharge a sheet P on which job information including the chronological relationship between the first print job and the second print job is printed.

[0036] In the illustrated example, print jobs are accepted in the order of job 1, job 2, job 3, and job 4. Jobs 1, 2, and 4 are the first print jobs, and job 3 is the second print job. Sheets P printed by jobs 1, 2, and 4 are discharged from first discharge section 41, and sheets P printed by job 3 are discharged from second discharge section 42.

[0037] The illustrated sheet P indicates that the sheet P printed by job 3 should be placed back between the sheets P printed by jobs 2 and 4. This allows the user to easily arrange the sheets P discharged from the first discharge section 41 and the second discharge section 42 in the order of the accepted print jobs.

[0038] FIG. 5 is a flowchart showing an image forming method executed by the image forming apparatus 1 according to one embodiment of the present invention.

[0039] When the first print job is accepted (Yes in step S101) and there is a print job for which the calculation of the estimated printing time has not been completed (No in step S102), the calculation unit 7 calculates the estimated printing time based on the printing performance of the image forming device 1 (step S103).

[0040] Next, if there is a print job for which calculation of the expected post-processing time has not been completed (No in step S104), calculation unit 7 calculates the expected post-processing time based on the post-processing performance of image forming apparatus 1 (step S105).

[0041] Next, if there is a print job for which calculation of the print job pause time has not been completed (No in step S106), the calculation unit 7 calculates the print pause time, which is the time obtained by subtracting the expected print time from the expected post-processing time (step S107).

[0042] Next, if there is a print job for which calculation of the cumulative print pause time has not been completed (No in step S108), the calculation unit 7 calculates the cumulative print pause time, which is the cumulative time of the print pause times of multiple first print jobs (step S109).

[0043] Next, the first print jobs, which are print jobs that have already been accepted, are checked in the order in which they were accepted, and if the estimated printing time of the first print job is equal to or greater than the cumulative print pause time of the first print job accepted immediately before the first print job (Yes in step S110), and is less than the print pause time obtained by subtracting the print pause time of the first print job from the cumulative print pause time of the first print job accepted immediately after the first print job (Yes in step S111), the selection unit 8 selects the first print job as the second print job (step S112).

[0044] When the confirmation after the above processing is completed (Yes in step S113), the processing ends.

[0045] 6 is a diagram illustrating the relationship between progress for each print job, post-processing speed, and printing speed in image forming apparatus 1 according to one embodiment of the present invention. The solid line in the graph shown indicates the number of sheets P for which post-processing has been completed. The dashed line in the graph shown indicates the number of sheets P for which printing has been completed. Arrow A in the diagram indicates the number of sheets P stacked in buffer unit 32.

[0046] In the illustrated example, print jobs are accepted in the order of Job 1, Job 2, Job 3, and Job 4, with Jobs 1, 2, and 4 being the first print jobs and Job 3 being the second print job. Each print job prints 400 sheets. The post-processing speed is 66 sheets / minute, the printing speed is 100 sheets / minute, and the buffer unit 32 becomes full with 68 sheets.

[0047] One minute after printing starts, 100 sheets have been printed by job 1 and post-processing has been performed on 66 sheets. 34 sheets P are stacked in the buffer unit 32. Two minutes after printing starts, 200 sheets have been printed by job 1 and post-processing has been performed on 132 sheets. 68 sheets P are stacked in the buffer unit 32.

[0048] Two minutes after printing starts, the buffer unit 32 becomes fully loaded with sheets P. Therefore, the buffer unit 32 sends a stop signal to stop printing of job 1, and printing of job 1 is temporarily stopped. Then, printing of job 3 starts, and the printed sheets P are discharged to the second discharge unit 42.

[0049] Three minutes after printing begins, post-processing has been completed for 198 sheets, and two sheets P remain in the buffer unit 32. Because the buffer unit 32 is not full of sheets P, the pause on printing of job 1 is released, and printing of job 1 resumes. The image forming apparatus 1 continues this process. Note that after a stop signal to stop printing is sent, printing of the print job whose printing has been stopped will not begin until the number of sheets stacked in the buffer unit 32 falls below a predetermined number. In the above case, the pause on printing of job 1 will not be released until the number of remaining sheets P reaches two, minus the number of sheets that can be post-processed in one minute (66).

[0050] Strictly speaking, given the printing speed and post-processing speed described above, the number of sheets P in the buffer unit 32 five minutes after printing begins is calculated to be 70. In other words, the buffer unit 32 will become full again shortly before five minutes have elapsed since printing began. To prevent this situation, if the number of remaining sheets to be printed in a job is a small, predetermined number, such as five or fewer, and the buffer unit 32 becomes full, a period of time may be set in which printing operations are temporarily stopped and only post-processing is performed. By performing this process, it is possible to prevent the buffer unit 32 from becoming full even if the remaining number of sheets P to be printed is printed.

[0051] In the illustrated example, 2-3 minutes and 5-6 minutes after printing starts, printing by Job 1, the first print job, stops, and printing by Job 3, the second print job, begins. 6 minutes after printing starts, printing by Job 2 begins, and 8-9 minutes and 11-12 minutes after printing starts, printing by Job 2, the first print job, stops, and printing by Job 3, the second print job, begins. Therefore, printing by Job 3 completes after printing by Jobs 1 and 2 completes, and then printing by Job 4 completes. Therefore, the print jobs are completed in the order they were received: Job 1, Job 2, Job 3, and Job 4.

[0052] Example 1 7 is a diagram showing Example 1 of the image forming apparatus 1 according to one embodiment of the present invention, in which (a) is a table showing job information of each print job, and (b) is a diagram showing the progress of each print job.

[0053] In the illustrated example, print jobs are accepted in the order of Job 1, Job 2, Job 3, and Job 4. Each print job is assumed to print 400 sheets. The printing speed is 100 sheets / minute, the post-processing speed is 66 sheets / minute, and the buffer unit 32 becomes full with 68 sheets. The time required for the buffer unit 32 to become full with sheets P is calculated as 68 / (100-66), which is approximately 2 minutes.

[0054] First, the accepted job is accepted as a first print job, and if the expected print time of the first print job is equal to or greater than the cumulative print pause time of the first print job accepted immediately before the first print job, and if the expected print time of the first print job is less than the cumulative print pause time of the first print job accepted immediately after the first print job, excluding the print pause time of the first print job, the first print job is selected as the second print job.

[0055] In the illustrated example, the estimated print time of job 2 is 4 minutes, which is greater than the cumulative print pause time of job 1, which is 2 minutes (Yes in S110 of FIG. 5), so job 2 becomes a candidate to be the second print job. Therefore, since job 2 becomes a candidate to be the second print job, subtracting the print pause time of job 2 (2 minutes) from the cumulative print pause time of the following job 3 (6 minutes) results in a cumulative print pause time of 4 minutes for the next job 3. And because the estimated print time of job 2 is 4 minutes, the cumulative print pause time of job 3 is not less than 4 minutes (No in S111 of FIG. 5), so job 2 is not selected as the second print job. Also, the estimated print time of job 3 is 4 minutes, which is greater than the cumulative print pause time of job 2, which is 4 minutes, so job 3 becomes a candidate to be the second print job. Therefore, since job 3 becomes a candidate to be the second print job, subtracting the print pause time of job 3 results in a cumulative print pause time of the next job 4, which is 6 minutes. The estimated printing time for job 3 is 4 minutes, which is less than the cumulative print pause time for job 4, which is 6 minutes.

[0056] Therefore, the print job whose estimated print time is equal to or longer than the cumulative print pause time of the job accepted immediately before and shorter than the cumulative print pause time of the job accepted immediately after is job 3. Therefore, the selection unit 8 selects job 3 as the second print job.

[0057] 7(b), while printing of the first print jobs, Job 1 and Job 2, is paused, printing of the second print job, Job 3, is executed. As a result, without any of the print jobs being stopped, the print jobs are completed in the order in which they were received: Job 1, Job 2, Job 3, and Job 4.

[0058] <Example 2> 8 is a diagram showing Example 2 of the image forming apparatus 1 according to one embodiment of the present invention. In Fig. 8, (a) and (b) are tables showing job information of each print job, and (c) is a diagram showing the progress of each print job.

[0059] In the illustrated example, print jobs are accepted in the order of Job 1, Job 2, Job 3, and Job 4. The print jobs Job 1, Job 2, Job 3, and Job 4 are assumed to print 400, 600, 800, and 1000 sheets, respectively. The printing speed is assumed to be 100 sheets / minute, the post-processing speed is assumed to be 66 sheets / minute, and the buffer unit 32 becomes full with 68 sheets. The time required for the buffer unit 32 to become full with sheets P is approximately 2 minutes, the same as in the first embodiment.

[0060] First, consider whether job 2 should be selected as the second print job. In the example shown in Figure 8(a), the expected print time for job 2 is 6 minutes, which is more than the cumulative print pause time of job 1, which is 2 minutes. However, it is not less than the cumulative print pause time of job 3, which is 6 minutes, excluding the print pause time of job 2, assuming job 2 is the second print job. Therefore, job 2 is not selected as the second print job.

[0061] Next, we consider whether job 3 should be selected as the second print job. As shown in the example in Figure 8(b), the expected print time for job 3 is 8 minutes, which is greater than the 5 minutes that is the cumulative print pause time for job 2. Furthermore, if job 3 is selected as the second print job, it is less than the 10 minutes that is the cumulative print pause time for job 4 excluding the print pause time for job 3.

[0062] Therefore, a print job whose estimated printing time is equal to or longer than the cumulative print pause time of the job accepted immediately before the print job in question, and shorter than the cumulative print pause time of the job accepted immediately after the print job in question, is job 3. Therefore, the selection unit 8 selects job 3 as the second print job.

[0063] As shown in Figure 8(c), while printing of the first print jobs, Job 1, Job 2, and Job 4, is paused, printing of the second print job, Job 3, is executed. As a result, without any of the print jobs being stopped, the print jobs are completed in the order in which they were received, that is, Job 1, Job 2, Job 3, and Job 4.

[0064] In the illustrated example, printing of pages 1 to 100 of job 3 is executed during a pause after pages 1 to 200 of job 1 have been printed. Then, pages 201 to 400 of job 1 are printed, and job 1 ends.

[0065] Next, while printing is paused after job 1 is completed, pages 101 to 200 of job 3 are printed, and pages 1 to 200 of job 2 are printed. While printing of job 2 is paused, pages 201 to 300 of job 3 are printed. After that, pages 201 to 400 of job 2 are printed. Then, while printing of job 2 is paused, pages 301 to 400 of job 3 are printed. Then, printing of pages 401 to 600 of job 2 is completed, and job 2 ends.

[0066] While printing is paused after job 2 is completed, pages 401 to 500 of job 3 are printed. Then, pages 1 to 200 of job 4 are printed, and during the subsequent printing pause, pages 501 to 600 of job 3 are printed. Then, pages 201 to 400 of job 4 are printed, and during the subsequent printing pause of job 4, pages 601 to 700 of job 3 are printed. Then, pages 401 to 600 of job 4 are printed, and during the subsequent printing pause of job 4, pages 701 to 800 of job 3 are printed, and job 3 is completed. Job 4 continues to be executed until it is completed.

[0067] Example 3 9 is a diagram showing Example 3 of the image forming apparatus 1 according to one embodiment of the present invention. In FIG. 9, (a) and (b) are tables showing job information of each print job, and (c) is a diagram showing the progress of each print job.

[0068] In the illustrated example, print jobs are accepted in the order of Job 1, Job 2, Job 3, and Job 4. The print jobs Job 1, Job 2, Job 3, and Job 4 are assumed to print 800 sheets, 200 sheets, 400 sheets, and 400 sheets, respectively. The printing speed is 100 sheets / minute, the post-processing speed is 66 sheets / minute, and the buffer unit 32 becomes full with 68 sheets. The time required for the buffer unit 32 to become full with sheets P is approximately 2 minutes, the same as in the first embodiment.

[0069] In the example shown in FIG. 9(a), the estimated print time for job 2 is 2 minutes, which is not more than the 4 minutes that is the cumulative print pause time for job 1. Similarly, the estimated print time for job 3 is 4 minutes, which is not more than the 5 minutes that is the cumulative print pause time for job 2. Furthermore, the estimated print time for job 4 is 4 minutes, which is not more than the 7 minutes that is the cumulative print pause time for job 3. Therefore, neither print job is selected as the second print job.

[0070] Therefore, if it becomes possible to execute the print job by delaying the timing of printing by the second print job to be discharged to the second discharge section 42, then it is considered to delay the execution of the second print job. More specifically, the timing of starting printing is delayed so that the cumulative printing pause time of the first print job is equal to or less than the estimated printing time of the first print job accepted immediately after the first print job.

[0071] In the example shown in Figure 9(b), consider whether job 2 will be selected as the second print job. The cumulative print pause time for job 1 is 4 minutes, and the estimated print time for job 2 is 2 minutes. If job 2 is to be selected as the second print job, the timing to start printing based on the estimated print time of job 2 is delayed until the cumulative print pause time becomes 2 minutes (4 minutes - 2 minutes). The time displayed in parentheses for "cumulative print pause time" in Figure 9(b) is the time when the timing to start printing for each print job is delayed by 2 minutes.

[0072] T1 in Figure 9(c) indicates the time for each time printing is paused during execution of Job 1. T2 indicates the time for which the start of printing by Job 2 is delayed. From Figure 9(b), the printing pause time for Job 1 is 4 minutes. Furthermore, printing is paused four times during execution of Job 1. Therefore, T1 is 1 minute.

[0073] The timing when printing by Job 2 starts is delayed by two minutes. In other words, Job 2 does not start printing for the two times printing is paused in Job 1. Therefore, the timing when printing by Job 2 starts is the timing when printing is paused for the third time in Job 1, as shown at T2 in Figure 9(c).

[0074] In this case, the estimated printing time for job 2 is 2 minutes, which is more than the cumulative print pause time of 2 minutes caused by delaying the timing to start printing of job 1. And, if job 2 is the second print job, it will be less than the cumulative print pause time of 4 minutes caused by delaying the timing to start printing of job 3 excluding the print pause time of job 2. Therefore, the selection unit 8 selects job 3 as the second print job.

[0075] 9(c), while printing of the first print job, Job 1, is paused, printing of the second print job, Job 2, is executed. As a result, without any of the print jobs being stopped, the print jobs are completed in the order in which they were received: Job 1, Job 2, Job 3, and Job 4.

[0076] <Action and effect> According to an image forming apparatus 1 according to an embodiment of the present invention, printing by a second print job begins during the waiting time of a first print job. The second print job has an expected printing time that is equal to or longer than the cumulative print pause time of the print job accepted immediately before, but shorter than the cumulative print pause time of the print job accepted immediately after. In other words, the second print job is a print job that can complete printing after printing by the first print job is completed, and can complete printing before the first print job that is executed next and completes printing.

[0077] Therefore, according to the image forming apparatus 1 according to one embodiment of the present invention, it is possible to improve the efficiency of printing and complete printing in the order in which print jobs are received.

[0078] [Other embodiments] The image forming apparatus 1 according to the above embodiment can be configured as an image forming system, in which case the image forming section 10, the conveying section 20, and the post-processing mechanism 30 can be configured as separate devices.

[0079] In this case, the image forming system includes a buffer unit 32, a first discharge unit 41, and a second discharge unit 42. The image forming system also includes a calculation unit that calculates an estimated printing time required for printing each print job based on the printing performance, and an estimated post-processing time required for post-processing each print job based on the post-processing performance. The image forming system also includes a selection unit that selects a second print job from the multiple print jobs based on the estimated printing time and the estimated post-processing time.

[0080] Although the embodiments have been described above, the present invention is not limited to the above-described embodiments, and various modifications and improvements are possible within the scope of the present invention.

[0081] Each function of the above-described embodiments can be realized by one or more processing circuits. Here, the term "processing circuit" in this specification includes a processor programmed to perform each function by software, such as a processor implemented by an electronic circuit, as well as devices such as an ASIC (Application Specific Integrated Circuit), a DSP (Digital Signal Processor), an FPGA (Field Programmable Gate Array), and conventional circuit modules designed to perform each of the above-described functions.

[0082] For example, aspects of the present invention are as follows. <1> a buffer unit that stores sheets printed by a first print job and not yet subjected to post-processing, and that transmits a stop signal to stop the first print job when the buffer unit is full of sheets; a first discharge unit that discharges the sheet that has been printed by the first print job and has been subjected to post-processing; a second ejection unit that ejects the sheets printed by a second print job that starts execution after the first print job is stopped upon receipt of the stop signal; a calculation unit that calculates an estimated printing time required for printing for each print job based on printing performance, and calculates an estimated post-processing time required for post-processing for each print job based on post-processing performance; a selection unit that selects the print job to be the second print job from the plurality of print jobs based on the estimated printing time and the estimated post-processing time; An image forming apparatus comprising: <2> The calculation unit calculating a print pause time, which is a time for stopping the first print job, and which is the time obtained by subtracting the estimated print time from the estimated post-processing time, and a cumulative print pause time, which is the cumulative total of the print pause times of a plurality of the first print jobs; The selection unit selecting the print job to be the second print job by comparing the estimated print time and the accumulated print pause time; The aforementioned <1> 2. The image forming apparatus according to claim 1 . <3> The selection unit the estimated printing time of the first print job is equal to or longer than the cumulative print pause time of the first print job accepted immediately before the first print job; If the estimated printing time of the first print job is less than the cumulative print pause time of the first print job accepted immediately after the first print job, excluding the print pause time of the first print job, selecting the first print job as the second print job; The aforementioned <2> 2. The image forming apparatus according to claim 1 . <4> After the printing of the series of print jobs is completed, the sheet on which job information including the chronological relationship between the first print job and the second print job is printed is discharged. The aforementioned <1> From the above <3> 10. The image forming apparatus according to claim 9, wherein: <5> a buffer unit that stores sheets printed by a first print job and not yet subjected to post-processing, and that transmits a stop signal to stop the first print job when the buffer unit is full of sheets; a first discharge unit that discharges the sheet that has been printed by the first print job and has been subjected to post-processing; a second ejection unit that ejects the sheets printed by a second print job that starts execution after the first print job is stopped upon receipt of the stop signal; a calculation means for calculating an estimated printing time required for printing for each print job based on the printing performance, and for calculating an estimated post-processing time required for post-processing for each print job based on the post-processing performance; a selection unit for selecting the print job to be the second print job from the plurality of print jobs based on the estimated printing time and the estimated post-processing time; An image forming system comprising: <6> a buffer unit for stacking sheets printed by a first print job and before being subjected to post-processing; a first discharge unit that discharges the sheet that has been printed by the first print job and has been subjected to post-processing; a second discharge unit that discharges the sheets printed by the second print job; An image forming method executed by an image forming apparatus comprising: transmitting a stop signal to stop the first print job when the sheets stacked in the buffer unit become full; starting execution of the second print job after the first print job is stopped upon receipt of the stop signal; calculating an estimated printing time required for printing for each print job based on the printing performance, and calculating an estimated post-processing time required for post-processing for each print job based on the post-processing performance; selecting the print job to be the second print job from the plurality of print jobs based on the estimated printing time and the estimated post-processing time; An image forming method comprising: <7> a buffer unit for stacking sheets printed by a first print job and before being subjected to post-processing; a first discharge unit that discharges the sheet that has been printed by the first print job and has been subjected to post-processing; a second discharge unit that discharges the sheets printed by the second print job; A program to be executed by an image forming apparatus comprising: a process of transmitting a stop signal to stop the first print job when the sheets stacked in the buffer unit become full; a process of starting execution of the second print job after the first print job is stopped by receiving the stop signal; A process of calculating an estimated printing time required for printing for each print job based on the printing performance, and calculating an estimated post-processing time required for post-processing for each print job based on the post-processing performance; a process of selecting the print job to be the second print job from the plurality of print jobs based on the estimated printing time and the estimated post-processing time; A program that executes the following. [Explanation of symbols]

[0083] 1. Image forming device 7 Calculation section 8 Selection section 31 Post-processing section 32 Buffer section 41 1st discharge section 42 2nd discharge section P-sheet [Prior art documents] [Patent documents]

[0084] [Patent Document 1] Japanese Patent Application Laid-Open No. 2000-335049

Claims

1. a buffer unit that stores sheets printed by a first print job and not yet subjected to post-processing, and that transmits a stop signal to stop the first print job when the buffer unit is full of sheets; a first discharge unit that discharges the sheet that has been printed according to the first print job and has been subjected to post-processing; a second ejection unit that ejects the sheets printed by a second print job that starts execution after the first print job is stopped upon receipt of the stop signal; a calculation unit that calculates an estimated printing time required for printing for each print job based on printing performance, and calculates an estimated post-processing time required for post-processing for each print job based on post-processing performance; a selection unit that selects the print job to be the second print job from the plurality of print jobs based on the estimated printing time and the estimated post-processing time; An image forming apparatus comprising:

2. The calculation unit calculating a print pause time, which is a time for stopping the first print job, and which is the time obtained by subtracting the estimated print time from the estimated post-processing time, and a cumulative print pause time, which is the cumulative total of the print pause times of a plurality of the first print jobs; The selection unit selecting the print job to be the second print job by comparing the estimated print time and the accumulated print pause time; The image forming apparatus according to claim 1 .

3. The selection unit the estimated printing time of the first print job is equal to or longer than the cumulative print pause time of the first print job accepted immediately before the first print job, If the estimated printing time of the first print job is less than the cumulative print pause time of the first print job accepted immediately after the first print job, excluding the print pause time of the first print job, selecting the first print job as the second print job; The image forming apparatus according to claim 2 .

4. After the printing of the series of print jobs is completed, the sheet on which job information including the chronological relationship between the first print job and the second print job is printed is discharged. The image forming apparatus according to claim 1 .

5. a buffer unit that stores sheets printed by a first print job and not yet subjected to post-processing, and that transmits a stop signal to stop the first print job when the buffer unit is full of sheets; a first discharge unit that discharges the sheet that has been printed according to the first print job and has been subjected to post-processing; a second ejection unit that ejects the sheets printed by a second print job that starts execution after the first print job is stopped upon receipt of the stop signal; a calculation means for calculating an estimated printing time required for printing for each print job based on the printing performance, and for calculating an estimated post-processing time required for post-processing for each print job based on the post-processing performance; a selection unit for selecting a print job to be the second print job from the plurality of print jobs based on the estimated printing time and the estimated post-processing time; An image forming system comprising:

6. a buffer unit for stacking sheets printed by a first print job and not yet subjected to post-processing; a first discharge unit that discharges the sheet that has been printed according to the first print job and has been subjected to post-processing; a second discharge unit that discharges the sheets printed by the second print job; An image forming method executed by an image forming apparatus comprising: transmitting a stop signal to stop the first print job when the sheets stacked in the buffer section become full; starting execution of the second print job after the first print job is stopped upon receipt of the stop signal; calculating an estimated printing time required for printing for each print job based on the printing performance, and calculating an estimated post-processing time required for post-processing for each print job based on the post-processing performance; selecting the print job to be the second print job from the plurality of print jobs based on the estimated printing time and the estimated post-processing time; An image forming method comprising:

7. a buffer unit for stacking sheets printed by a first print job and not yet subjected to post-processing; a first discharge unit that discharges the sheet that has been printed according to the first print job and has been subjected to post-processing; a second discharge unit that discharges the sheets printed by the second print job; A program to be executed by an image forming apparatus comprising: a process of transmitting a stop signal to stop the first print job when the sheets stacked in the buffer section become full; a process of starting execution of the second print job after the first print job is stopped upon receipt of the stop signal; A process of calculating an estimated printing time required for printing for each print job based on the printing performance, and calculating an estimated post-processing time required for post-processing for each print job based on the post-processing performance; selecting a print job to be the second print job from the plurality of print jobs based on the estimated printing time and the estimated post-processing time; A program that executes the following.

Images