Image forming system and method

Abstract

To provide an image formation system capable of properly making the sizes of output sheets of paper uniform, and a method.SOLUTION: An image formation system comprises: a reading part that reads a recording medium; an acquisition part that acquires information on the size of the recording medium on the basis of the result of reading by the reading part; and a control part that performs control so that the reading medium satisfying prescribed conditions based on a preset standard size and the reading medium not satisfying the prescribed conditions based on the preset standard size can be discriminated and ejected on the basis of the information on the size.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] This disclosure relates to Image forming system and Appearance a method.

Background Art

[0002] Conventionally, an image forming apparatus that forms and outputs an image on a recording medium such as paper is known. In such an image forming apparatus, when forming the same image on a plurality of sheets of paper, a stack of sheets of paper is set in a paper feeding unit, and the sheets are sequentially fed one by one to form the same image on the paper (see, for example, Patent Document 1). In such an image forming apparatus, a packaged stack of paper is often used.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, although the packaged paper is manufactured to have the same size according to a common standard, the size is slightly different for each sheet of paper. For example, the size may be significantly different between the top sheet and the bottom sheet. This is because the sheets constituting the stack of paper are cut from a single large sheet of paper and are affected by the errors generated during cutting.

[0005] Therefore, when forming the same image on each sheet of paper using such a stack of paper, the user cannot perform image formation of the desired quality. Also, when outputting a large amount of paper using the sheets of a plurality of stacks of paper, a large deviation may occur in the discharged paper, and the sheets may not be properly aligned.

[0006] The present disclosure has been made in view of the problems in the above-described conventional technologies, and aims to provide a method capable of appropriately aligning the sizes of the output sheets. Image forming system and Appearance a method.

Means for Solving the Problem

[0007] An image forming system according to the present disclosure includes A paper feeding unit in which a recording medium is accommodated and an accommodation size regarding the size of the accommodated recording medium is set The a reading unit that reads a recording medium, an acquisition unit that acquires information regarding the size of the recording medium based on the reading result of the reading unit, Regarding the recording medium accommodated in the paper feeding unit in which the predetermined accommodation size is set, the difference between the information regarding the size acquired by the acquisition unit and the information regarding the reference size preset corresponding to the accommodation size is within the range of a preset allowable value a recording medium, The difference is not within the range of the allowable value and a control unit that controls so that the recording media are discharged separately. The image forming system is provided with these components.

[0008] A method according to the present disclosure is A paper feeding unit in which a recording medium is accommodated and an accommodation size regarding the size of the accommodated recording medium is set a method executed in an image forming system, the method including a step of reading a recording medium by a reading unit, a step of acquiring information regarding the size of the recording medium based on the reading result of the reading unit, Regarding the recording medium accommodated in the paper feeding unit in which the predetermined accommodation size is set, the difference between the information regarding the size acquired and the information regarding the reference size preset corresponding to the accommodation size is within the range of a preset allowable value a step of controlling so that the recording media are discharged separately. The difference is not within the range of the allowable value The method is provided with these steps. The method is provided with these steps.

Advantages of the Invention

[0010] According to the present disclosure, the sizes of the output sheets can be appropriately aligned.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

[0012] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. The present disclosure is not limited to the following embodiments, and various modifications can be made without departing from the gist of the present disclosure. Also, in each figure, those denoted by the same reference numerals are the same or corresponding ones, which is common throughout the entire specification.

[0013] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. The image forming system according to the present embodiment is capable of forming an image on a sheet of paper (recording medium) such as a single-sheet paper.

[0014] [Configuration of Image Forming System 1] FIG. 1 is a schematic diagram showing an example of the configuration of an image forming system 1 according to the present embodiment. Further, FIG. 2 is a block diagram showing the main part of the control system of the image forming system 1 according to the present embodiment. As shown in FIG. 1, the image forming system 1 includes an image forming apparatus 100, a paper feeding unit 200, a reading unit 300, an upstream paper discharging unit 600, a downstream paper discharging unit 400, and the like. Also, a paper discharging apparatus according to the present embodiment is configured by a configuration including the reading unit 300 and the upstream paper discharging unit 600 or the downstream paper discharging unit 400.

[0015] The image forming apparatus 100 is an intermediate transfer type color image forming apparatus that uses electrophotographic process technology. That is, the image forming apparatus 100 primarily transfers the CMYK toner images of each color formed on the photoreceptor to the intermediate transfer member, overlaps the four-color toner images on the intermediate transfer member, and then secondarily transfers them to the paper to form an image. Note that CMYK refers to C (cyan), M (magenta), Y (yellow), and K (black).

[0016] The image forming apparatus 100 employs a tandem method in which photoreceptors corresponding to the four colors of CMYK are arranged in series in the running direction of the intermediate transfer member, and the toner images of each color are sequentially transferred to the intermediate transfer member in a single procedure.

[0017] As shown in FIG. 2, the image forming system 1 includes an image processing unit 10, an image forming unit 20, a fixing unit 30, a paper conveyance unit 40, an operation display unit 50, a communication unit 71, a storage unit 72, a control unit 500, a paper feeding unit 200, a reading unit 300, an upstream paper discharge unit 600, a downstream paper discharge unit 400, and the like.

[0018] The image processing unit 10 includes a circuit or the like that performs image processing on the input image data according to initial settings or user settings. Based on the image data subjected to image processing, the image forming unit 20 is controlled.

[0019] The image forming unit 20 includes an image forming unit 21, an intermediate transfer unit 22, a secondary transfer unit 23, and the like. The image forming unit 21 forms an image with colored toner of each color component based on the image data from the image processing unit 10. For example, it forms an image with colored toner of each color component of Y (yellow), M (magenta), C (cyan), and K (black).

[0020] The image forming unit 21 has, for each color, an exposure device, a developing device, a photoreceptor drum, a charging device, a drum cleaning device, and the like. Since known technologies can be adopted as the exposure device, the developing device, the photoreceptor drum, the charging device, and the drum cleaning device, detailed descriptions thereof are omitted here.

[0021] The intermediate transfer unit 22 includes an intermediate transfer belt or the like. The intermediate transfer belt is looped around a plurality of support rollers and runs in the direction of arrow A. The support rollers include rollers such as a backup roller, a primary transfer roller, and a drive roller, but the illustration of these is omitted here. The intermediate transfer belt is pressed against the photosensitive drum, and thereby, the toner image is transferred from the photosensitive drum to the intermediate transfer belt.

[0022] Note that the intermediate transfer unit 22 may be configured to include a belt cleaning device having a plate-like belt cleaning blade or the like that slidably contacts the surface of the intermediate transfer belt. The belt cleaning device removes transfer residual toner or the like remaining on the surface of the intermediate transfer belt after secondary transfer.

[0023] The secondary transfer unit 23 includes a secondary transfer roller or the like. The secondary transfer roller is pressed against the intermediate transfer belt. Thereby, a secondary transfer nip is formed between the intermediate transfer belt and the secondary transfer roller.

[0024] In the secondary transfer unit 23, when the sheet is conveyed to the secondary transfer nip, the toner images of each color carried on the intermediate transfer belt are collectively transferred onto the sheet. The sheet onto which the toner image has been transferred is conveyed by the secondary transfer roller toward the fixing unit 30.

[0025] Note that the secondary transfer unit 23 may be a belt type secondary transfer unit having a secondary transfer belt or the like looped around a plurality of support rollers instead of a roller type secondary transfer unit having a secondary transfer roller or the like.

[0026] The fixing unit 30 includes a fixing roller, a pressure roller, and the like. The fixing roller is heated to a predetermined fixing temperature, and the pressure roller forms a fixing nip for sandwiching and conveying the sheet between the fixing roller. In this fixing unit 30, the sheet onto which the toner image has been secondarily transferred and conveyed is heated and pressed by the fixing nip to fix the toner image on the sheet.

[0027] The paper conveyance unit 40 includes a conveyance path unit 41 and the like. The conveyance path unit 41 is composed of, for example, a path for conveying paper, a plurality of conveyance rollers, and a drive motor for rotationally driving these conveyance rollers. The conveyance path unit 41 conveys the paper supplied from the paper feeding unit 200 to the secondary transfer unit 23 and the fixing unit 30, and then conveys it to the downstream paper discharge unit 400.

[0028] In the conveyance path unit 41, a registration roller pair 41a is provided upstream of the secondary transfer unit 23 in the paper conveyance direction D. The registration roller pair 41a adjusts the conveyance timing and orientation (angle) of the paper conveyed to the secondary transfer unit 23.

[0029] The operation display unit 50 is composed of, for example, a liquid crystal display (LCD) with a touch panel, etc., and functions as a display unit and an operation unit. The display unit performs displays such as various operation screens, status displays of images, and operation statuses of each function according to the display control signal input from the control unit 500. The operation unit includes various operation keys such as numeric keys and a start key, accepts various input operations by the user, and outputs an operation signal to the control unit 500.

[0030] The paper feeding unit 200 is arranged upstream of the image forming apparatus 100 in the paper conveyance direction D, and is connected to the image forming apparatus 100 via a reading unit 300 and an upstream paper discharge unit 600 to be described later. The paper feeding unit 200 has a plurality of paper feeding trays 201, 202, and 203, and each paper feeding tray 201, 202, and 203 houses sheet-fed papers (standard papers or special papers) identified based on basis weight or size, etc. for each preset type. The paper feeding unit 200 supplies the designated paper to the image forming apparatus 100 side based on an instruction from the image forming apparatus 100.

[0031] The reading unit 300 is disposed between the paper feeding unit 200 and the upstream paper discharging unit 600, and is connected to the paper feeding unit 200 on the upstream side and to the image forming apparatus 100 on the downstream side in the paper conveyance direction D.

[0032] The reading unit 300 includes sensors 301 and 302 that read the paper conveyed from the paper feeding unit 200. The sensor 301 is disposed above the path along which the paper is conveyed, is disposed facing the conveyed paper side, and is configured to read the front (upper) surface side of the conveyed paper. The sensor 302 is disposed below the path along which the paper is conveyed, is disposed facing the conveyed paper side, and is configured to read the back (lower) surface side of the conveyed paper.

[0033] As the sensors 301 and 302, for example, a CCD (Charge Coupled Devices) or a CIS (Contact Image Sensor) or the like is used. Further, as the sensors 301 and 302, a line sensor extending over a width equal to or greater than the width of the paper (width in the direction orthogonal to the paper conveyance direction D), for example, a line scanner or a line sensor camera or the like is used.

[0034] The sensors 301 and 302 acquire information regarding the paper. The sensors 301 and 302 acquire, as information regarding the paper, for example, the size of the paper (paper width, paper length, etc.), and the paper position and the like.

[0035] Here, as an example, the reading unit 300 is configured to include the sensors 301 and 302 that read both sides (front and back surfaces) of the paper, but the present invention is not limited thereto. For example, a configuration including only the sensor 301 that reads one side (front surface) of the paper may be employed.

[0036] The upstream paper discharge unit 600 is connected to the reading unit 300 on the upstream side and to the image forming apparatus 100 on the downstream side in the paper conveyance direction D. The upstream paper discharge unit 600 has a purge tray 601, and based on the reading result of the paper by the reading unit 300, conveys the paper to the image forming apparatus 100 or discharges the paper to the purge tray 601.

[0037] For example, when the paper size satisfies a predetermined condition, the upstream paper discharge unit 600 conveys the paper to the image forming apparatus 100. Further, when the paper size does not satisfy the predetermined condition, the upstream paper discharge unit 600 discharges the paper to the purge tray 601 as indicated by the dashed arrow in FIG. 1. In the present embodiment, when the size of the paper read by the reading unit 300 does not fall within a predetermined size, the upstream paper discharge unit 600 discharges the paper to the purge tray 601.

[0038] Here, as an example, the image forming system 1 is configured to include the upstream paper discharge unit 600. However, for example, a configuration that does not include the upstream paper discharge unit 600 may also be used. In such a configuration, based on the reading result of the paper by the reading unit 300, when the paper size does not satisfy a predetermined condition, the paper is conveyed by the paper conveyance unit 40 to the downstream paper discharge unit 400 without forming an image (hereinafter, appropriately referred to as "printing") by the image forming unit 20.

[0039] The downstream paper discharge unit 400 is disposed on the downstream side of the image forming apparatus 100 and is connected to the image forming apparatus 100 in the paper conveyance direction D. The downstream paper discharge unit 400 has a discharge tray 401 and a purge tray 402, and discharges the paper conveyed from the image forming apparatus 100 to the discharge tray 401 or the purge tray 402.

[0040] The paper discharge tray 401 discharges the paper on which an image has been formed by the image forming apparatus 100. The purge tray 402 discharges the paper whose paper size has not satisfied a predetermined condition as a result of the paper size being read by the reading unit 300. For example, when the paper size read by the reading unit 300 does not satisfy the predetermined condition, the downstream paper discharge unit 400 may discharge the paper on which no image has been formed by the image forming apparatus 100 from the purge tray 402 as indicated by the dashed arrow in FIG. 1.

[0041] The control unit 500 is connected to the above-described image processing unit 10, image forming unit 20, fixing unit 30, paper conveyance unit 40, operation display unit 50, communication unit 71, storage unit 72, paper supply unit 200, reading unit 300, upstream paper discharge unit 600, and downstream paper discharge unit 400. The control unit 500 gives various instructions to these units and executes predetermined processing.

[0042] In the present embodiment, the control unit 500 performs a correction coefficient calculation process for calculating a correction coefficient for correcting the size of the paper read by the reading unit 300. Further, when the size of the paper is not the desired size, the control unit 500 performs a purge process for purging the paper. Details of the correction coefficient calculation process and the purge process will be described later.

[0043] The control unit 500 includes a CPU (Central Processing Unit) 501, a ROM (Read Only Memory) 502, a RAM (Random Access Memory) 503, and the like. The CPU 501 reads out a program corresponding to the processing content from the ROM 502 and expands it in the RAM 503, and centrally controls the operations of the respective blocks of the image forming system 1 in cooperation with the expanded program. At this time, various data such as a LUT (Look Up Table) stored in the storage unit 72 is referred to. The storage unit 72 is configured by, for example, a nonvolatile semiconductor memory (so-called flash memory) or a hard disk drive.

[0044] The control unit 500 transmits and receives various data to and from an external device (e.g., a personal computer) connected to a communication network such as a LAN (Local Area Network) or WAN (Wide Area Network) via the communication unit 71. The control unit 500 receives, for example, image data transmitted from an external device, and forms an image on paper based on this image data (input image data). The communication unit 71 is composed of, for example, a communication control card such as a LAN card.

[0045] Also, the control unit 500 includes a counter 505. The counter 505 counts the number of sheets of paper that are continuously purged during the purge process.

[0046] Furthermore, the control unit 500 has functions as an arithmetic unit and a comparison unit. The arithmetic unit performs various arithmetic operations performed during the correction coefficient calculation process or the purge process. The comparison unit performs various comparisons performed during the purge process.

[0047] Specifically, during the correction coefficient calculation process, for example, the arithmetic unit calculates a correction coefficient for correcting the read size based on the size of the paper read by the reading unit 300 (hereinafter appropriately referred to as the "read size") and a preset reference paper size.

[0048] Also, during the purge process, the arithmetic unit calculates a corrected paper size obtained by correcting the read size based on the read size and the calculated correction coefficient. Furthermore, the arithmetic unit calculates a size difference value, which is the absolute value of the difference between the calculated corrected paper size and the reference paper size.

[0049] The comparison unit compares, for example, the size difference value calculated by the arithmetic unit with the difference deviation amount, and based on the comparison result, determines whether to purge the paper. The difference deviation amount is an allowable value for the size difference value, and indicates the allowable deviation amount from the reference paper size in the corrected paper size.

[0050] Further, the comparison unit compares the count value of the counter 505 with the number of consecutive NG sheets, and determines whether to cancel the job based on the comparison result. The number of consecutive NG sheets indicates the number of sheets serving as a criterion for canceling the job when the sheets are continuously purged.

[0051] [Operation of Image Forming System 1] In the image forming system 1 according to the present embodiment having the above configuration, when forming an image on a sheet of paper as a recording medium, the sheets are accommodated in the paper feed trays 201, 202, and 203 of the paper feed unit 200. Then, the sheets supplied from the paper feed unit 200 are conveyed to the image forming apparatus 100, printing is performed in the image forming apparatus 100, and then conveyed to the downstream paper discharge unit 400.

[0052] By the way, when forming an image on a large number of sheets, the paper feed trays 201, 202, and 203 often accommodate sheets of a packaged paper bundle. At this time, even if the packaged sheets are of the same standard, the sheet size may be different from the assumed size. This is because the sheets included in the paper bundle are cut from large sheets and are affected by the errors generated during cutting.

[0053] FIG. 3 is a schematic diagram for explaining the sheet size of the paper bundle. FIG. 3 shows an example of a paper bundle when the paper is viewed from a direction orthogonal to the conveyance direction. Further, this example shows a state in which two packaged paper bundles are stacked.

[0054] This example shows a state in which an error of about 1 mm occurs between the size of the top sheet and the size of the bottom sheet for each paper bundle. Such an error is because when cutting a large sheet, the sheet is not cut perpendicular to the surface but is cut at a predetermined angle. In this case, when the size gradually decreases from the top to the bottom of the paper bundle and the top sheet is cut to conform to the standard, the bottom sheet will be about 1 mm shorter than the size according to the standard.

[0055] When printing an image on paper of a size different from the size defined by the standard, printing may not be performed properly, and printed materials of the quality desired by the user may not be obtained. Further, when a large number of printed materials are output using the paper in a plurality of paper bundles, a large deviation may occur in the discharged paper, and the paper may not be properly aligned.

[0056] Therefore, the image forming system 1 according to the present embodiment reads the paper size in the reading unit 300, and based on the reading result, performs a purge process of discharging paper that cannot be used for printing. In the purge process, a permissible deviation amount from the actual paper size is set in advance, and paper having a size read with an error larger than the set deviation amount is purged.

[0057] On the other hand, the paper size read by the reading unit 300 may be different from the actual paper size. This is because the distance between the sensors 301 and 302 and the paper is not constant for each device, and a reading error, which is an error between the actual paper size and the read size, occurs, so that the paper size cannot be accurately read.

[0058] Therefore, when a job is reserved or executed, the image forming system 1 according to the present embodiment performs a correction coefficient calculation process for calculating a correction coefficient for correcting the reading error prior to the above-described purge process.

[0059] (Correction Coefficient Calculation Process) FIG. 4 is a flowchart showing an example of the flow of the correction coefficient calculation process by the image forming system 1 according to the present embodiment. First, before the correction coefficient calculation process is performed, the actually measured size of the paper is measured in advance by the user. The actually measured size of the paper is manually measured by the user, for example. At this time, the user may take out the top paper from the packaged paper used for printing and measure the size of the taken-out paper. Further, without being limited thereto, the actually measured size of the paper may be stored in advance in the storage unit 72.

[0060] When the actual size of the paper is measured, in step S1, the actual size of the paper measured by the user is input by an operation on the operation display unit 50. The operation display unit 50 supplies size information including the actual size of the paper input by the user to the control unit 500. The control unit 500 stores the actual size of the paper included in the received size information in the storage unit 72 as the reference paper size.

[0061] FIG. 5 is a schematic diagram showing an example of the actual size setting screen 51 displayed on the operation display unit 50. As shown in FIG. 5, an actual size setting screen 51 including a conveyance direction size input box 52, a conveyance direction cross size input box 53, and a measurement start button 54 is displayed on the operation display unit 50.

[0062] The conveyance direction size input box 52 is selected by a touch operation or the like of the user when inputting a numerical value indicating the actual size in the conveyance direction of the paper. When the conveyance direction size input box 52 is selected, for example, a numerical value input button such as a numeric keypad is displayed on the operation display unit 50. Then, by operating the numerical value input button by the user, the actual size (conveyance direction size) in the conveyance direction of the paper is input. In this example, a state where "210.0 mm" is input as the conveyance direction size is shown.

[0063] The conveyance direction cross size input box 53 is selected by a touch operation or the like of the user when inputting a numerical value indicating the actual size in the direction crossing the conveyance direction of the paper. When the conveyance direction cross size input box 53 is selected, for example, a numerical value input button such as a numeric keypad is displayed on the operation display unit 50. Then, by operating the numerical value input button by the user, the actual size (conveyance direction cross size) in the direction crossing the conveyance direction of the paper is input. In this example, a state where "297.0 mm" is input as the conveyance direction cross size is shown.

[0064] The measurement start button 54 is selected by the user when the paper size is read by the reading unit 300. When the measurement start button 54 is operated, the measurement of the paper size by the reading unit 300 is started.

[0065] When the measurement start button 54 displayed on the actual measurement size setting screen 51 of the operation display unit 50 is selected, in step S2 of FIG. 4, the control unit 500 reads the paper size using the sensors 301 and 302 of the reading unit 300 and acquires the read size. The sensors 301 and 302 supply information including the read size to the control unit 500.

[0066] In step S3, the control unit 500 reads out the reference paper size stored in the storage unit 72. Then, the arithmetic unit of the control unit 500 calculates a reading error based on the reference paper size, which is the actual measured size of the paper, and the read size by the reading unit 300.

[0067] Specifically, when the read size is “X” and the reference paper size (actual measured size) is “Y”, the control unit 500 calculates “Y / X” obtained by dividing the reference paper size Y by the read size X as the reading error. For example, when the reference paper size X of the paper in the conveyance direction is 210 mm and the read size Y is 209.5 mm, the reading error is “Y / X = 210 / 209.5 (≈1.0024)”.

[0068] Therefore, for the paper on which an image is to be printed, when the read size read by the reading unit 300 is 209.5 mm, the actual paper size is “209.5×210 / 209.5 = 210 mm”, and it can be seen that the actual paper size is 210 mm.

[0069] In step S4, the control unit 500 stores the calculated reading error as a correction coefficient in the storage unit 72. Then, a series of correction coefficient calculation processes ends.

[0070] Such correction coefficient calculation processing is performed for each type of paper classified according to the standard, and a correction coefficient is calculated according to the type of paper. As a result, since the corrected paper size is calculated using the correction coefficient corresponding to each type of paper, the size of the read paper can be appropriately corrected.

[0071] Also, depending on the job to be reserved or executed, there may be a case where multiple types of papers such as A4 size and A3 size are mixed. In that case, the control unit 500 calculates a correction coefficient (reading error) for each type based on the size of the first sheet of each type in the job.

[0072] (Purge process) Next, the purge process will be described. FIG. 6 is a flowchart showing an example of the flow of the purge process by the image forming system 1 according to the present embodiment.

[0073] First, in step S11, the difference deviation amount and the continuous NG sheet count are input by an operation on the user operation display unit 50. The operation display unit 50 supplies information including the difference deviation amount and the continuous NG sheet count input by the user to the control unit 500. The control unit 500 stores and sets the difference deviation amount and the continuous NG sheet count included in the received information in the storage unit 72.

[0074] Here, setting the continuous NG sheet count is to prevent a large amount of paper from being purged. This is because, for example, assuming that the size of the paper in the paper bundle sequentially changes from top to bottom as shown in FIG. 3, if a predetermined number of sheets are continuously purged, there is a high possibility that the subsequent papers will also be purged.

[0075] FIG. 7 is a schematic diagram showing an example of a purge setting screen 55 for setting the difference deviation amount and the continuous NG sheet count, which is displayed on the operation display unit 50. As shown in FIG. 7, a purge setting screen 55 including a difference deviation amount input box 56 and a continuous NG sheet count input box 57 is displayed on the operation display unit 50.

[0076] When inputting the differential deviation amount, the differential deviation amount input box 56 is selected by the user's touch operation or the like. When the differential deviation amount input box 56 is selected, for example, numeric input buttons such as a numeric keypad are displayed on the operation display unit 50. Then, when the user operates the numeric input button, the differential deviation amount is input. In this example, a state where "0.5 mm" is input as the differential deviation amount is shown.

[0077] When inputting the number of consecutive NG sheets, the number of consecutive NG sheets input box 57 is selected by the user's touch operation or the like. When the number of consecutive NG sheets input box 57 is selected, for example, numeric input buttons such as a numeric keypad are displayed on the operation display unit 50. Then, when the user operates the numeric input button, the allowable number of consecutive NG sheets is input. In this example, a state where "5 sheets" is input as the number of consecutive NG sheets is shown.

[0078] Returning to FIG. 6, in step S12, the control unit 500 initializes the value of the counter 505 that counts the number of consecutive NG sheets. Then, in step S13, the control unit 500 starts paper feeding. As a result, paper is discharged from the paper feeding unit 200 and supplied to the reading unit 300.

[0079] Next, in step S14, the control unit 500 reads the size of the paper conveyed to the reading unit 300 using the sensors 301 and 302 of the reading unit 300. The sensors 301 and 302 supply information including the read size of the read paper to the control unit 500.

[0080] In step S15, the control unit 500 reads out the correction coefficient stored in the storage unit 72. Then, the arithmetic unit of the control unit 500 calculates a corrected paper size obtained by correcting the read size received from the sensors 301 and 302 using the correction coefficient. Specifically, for example, the arithmetic unit calculates the corrected paper size by multiplying the read size by the correction coefficient.

[0081] In step S16, the arithmetic unit reads out the reference paper size stored in the storage unit 72, and calculates a size difference value which is the absolute value of the difference between the reference paper size and the correction paper size. Next, the comparison unit of the control unit 500 compares the size difference value with the deviation amount set in step S11. As a result of the comparison, if the size difference value is less than or equal to the deviation amount (step S16: NO), the process proceeds to step S17.

[0082] In step S17, the paper for which it is determined that the size difference value is less than or equal to the deviation amount is conveyed from the reading unit 300 to the image forming apparatus 100 via the upstream paper discharge unit 600. The control unit 500 forms an image on the paper conveyed to the image forming apparatus 100. The paper on which the image is formed is conveyed to the downstream paper discharge unit 400 and discharged from the paper discharge tray 401.

[0083] In step S18, the control unit 500 resets the count of the number of consecutive NG sheets by the counter 505.

[0084] In step S19, the control unit 500 determines whether the paper discharged to the paper discharge tray 401 in step S17 is the last sheet of the job. As a result of the determination, if the paper is the last sheet (step S19: YES), the series of processes ends. On the other hand, if the paper is not the last sheet (step S19: NO), the process returns to step S13.

[0085] On the other hand, in step S16, if the size difference value is larger than the deviation amount (step S16: YES), the process proceeds to step S20. In step S20, the paper for which it is determined that the size difference value is larger than the deviation amount is conveyed from the reading unit 300 to the upstream paper discharge unit 600 and purged by being discharged from the purge tray 601.

[0086] In addition, when the upstream paper discharge unit 600 is not provided in the image forming system 1, the paper for which it is determined that the size difference value is larger than the difference deviation amount may be discharged from the downstream paper discharge unit 400. In this case, the paper is conveyed from the reading unit 300 to the image forming apparatus 100, but is conveyed to the downstream paper discharge unit 400 without the image being formed by the image forming apparatus 100. Then, the paper conveyed to the downstream paper discharge unit 400 is purged by being discharged from the purge tray 402.

[0087] In step S21, the control unit 500 increments the count value of the continuous NG sheet count by the counter 505 by 1.

[0088] In step S22, the control unit 500 compares the count value indicating the continuous NG sheet count of the counter 505 with the set value of the continuous NG sheet count, and determines whether the count value is greater than the set value. As a result of the comparison, when the count value of the continuous NG sheet count is larger than the set value (step S22: YES), the control unit 500 determines that the number of continuous NG sheets has exceeded the allowable number. In this case, the control unit 500 aborts the current job. Then, the series of processes ends.

[0089] On the other hand, when the count value is less than or equal to the set value (step S22: NO), the control unit 500 determines that the number of continuous NG sheets has not exceeded the allowable number. Then, the process returns to step S13.

[0090] Note that the purge process is performed in a state where the correction coefficient is calculated by the correction coefficient calculation process described above. However, when it is not necessary to correct the paper size, the purge process may be performed without performing the correction coefficient calculation process. In this case, after the size of the paper is read in step S14, the arithmetic unit of the control unit 500 calculates, in step S16, the absolute value of the difference between the reference paper size and the read size as the size difference value.

[0091] As described above, in the image forming system 1 according to the present embodiment, a sheet of paper having a size difference value, which is the difference between the read size of the sheet and the reference sheet size, greater than a predetermined deviation amount is purged. As a result, only sheets of paper having a size within a predetermined range of deviation amounts are used for image formation. Therefore, even when a large number of sheets are output, the deviation in the size of the sheets can be tolerated, and the sizes of the output sheets can be appropriately aligned.

[0092] Further, the arithmetic unit of the control unit 500 calculates a correction coefficient for correcting the size of the sheet read by the reading unit 300, and calculates a corrected sheet size obtained by correcting the read size using the correction coefficient. As a result, the read size read by the reading unit 300 is corrected so as to be the actual sheet size. Therefore, the image forming system 1 can accurately acquire the size of the sheet.

Explanation of Signs

[0093] 1 Image forming system 50 Operation display unit 51 Measured size setting screen 52 Conveying direction size input box 53 Conveying direction cross size input box 54 Measurement start button 55 Purge setting screen 56 Deviation amount input box 57 Consecutive NG sheet number input box 100 Image forming apparatus 200 Sheet feeding unit 201, 202, 203 Sheet feeding trays 300 Reading unit 301, 302 Sensors 400 Downstream paper discharge unit 401 Paper discharge tray 402, 601 Purge trays 500 Control unit 505 Counter 600 Upstream paper discharge unit

Claims

1. A paper feeding unit in which a recording medium is accommodated and an accommodation size regarding the size of the accommodated recording medium is set, A reading unit that reads the recording medium, An acquisition unit that acquires information regarding the size of the recording medium based on the reading result of the reading unit, For a recording medium accommodated in the paper feeding unit with a predetermined accommodation size, a difference between the information regarding the size acquired by the acquisition unit and information regarding a reference size preset corresponding to the accommodation size is within a preset allowable value range, and a control unit that controls to distinguish and discharge a recording medium whose difference is within the allowable value range from a recording medium whose difference is not within the allowable value range An image forming system comprising the same.

2. The control unit Controls so that a recording medium whose difference is within the allowable value range and a recording medium whose difference is not within the allowable value range are discharged to different discharge destinations The image forming system according to claim 1.

3. The information regarding the size of the recording medium Is a value obtained by correcting the size of the recording medium based on the reading result of the reading unit The image forming system according to claim 1 or 2.

4. Further comprising an image forming unit that forms an image on the recording medium, The control unit Controls whether to form the image on the recording medium to be discharged based on whether the difference is within the allowable value range The image forming system according to claim 1.

5. Further comprising an image forming unit that forms an image on the recording medium, A first discharge unit provided upstream of the image forming unit in the conveyance path of the recording medium, A second discharge unit provided downstream of the image forming unit in the conveyance path of the recording medium Further comprising the same, The control unit discharges the recording medium for which the difference is not within the allowable value range to the first discharge unit. The image forming system according to claim 2.

6. An image forming unit that forms an image on the recording medium; a second discharge unit provided downstream of the image forming unit in the conveyance path of the recording medium; and further includes: The second discharge unit has a first tray and a second tray, The control unit discharges the recording medium for which the difference is not within the allowable value range to the second tray. The image forming system according to claim 2.

7. The reading unit is provided in the conveyance path through which the recording medium is conveyed, and reads the conveyed recording medium. The image forming system according to claim 1 or 2.

8. further includes an image forming unit that forms an image on the recording medium, The reading unit is provided upstream of the image forming unit in the conveyance path through which the recording medium is conveyed. The image forming system according to claim 1 or 2.

9. The predetermined accommodation size is the size of the recording medium defined by the standard. The image forming system according to claim 1 or 2.

10. The recording medium accommodated corresponding to the predetermined accommodation size is the recording medium included in a bundle of sheets cut corresponding to a predetermined size. The image forming system according to claim 1 or 2.

11. The difference is caused by being cut corresponding to a predetermined size. The image forming system according to claim 1 or 2.

12. The control unit compares information on the size acquired by the acquisition unit with information on a reference size preset corresponding to the accommodation size, for a recording medium accommodated in the paper feed unit in which the predetermined accommodation size is set, and determines whether or not the difference is within the range of the allowable value. The image forming system according to claim 1 or 2.

13. A method executed in an image forming system including a paper feed unit in which a recording medium is accommodated and an accommodation size regarding the size of the accommodated recording medium is set, the method comprising: reading the recording medium by a reading unit; acquiring information on the size of the recording medium based on a reading result of the reading unit; controlling so that a recording medium for which a difference between the information on the size acquired and information on a reference size preset corresponding to the accommodation size is within a preset allowable value range, and a recording medium for which the difference is not within the allowable value range are discharged separately for a recording medium accommodated in the paper feed unit in which the predetermined accommodation size is set; A method comprising the above steps.

14. The method according to claim 13, wherein the controlling step controls so that a recording medium for which the difference is within the allowable value range and a recording medium for which the difference is not within the allowable value range are discharged to different discharge destinations.

15. The method according to claim 13 or 14, wherein the predetermined accommodation size is the size of the recording medium defined by a standard.

16. The method according to claim 13 or 14, wherein the recording medium accommodated corresponding to the predetermined accommodation size is a recording medium included in a bundle of papers cut corresponding to a predetermined size.

17. The method according to claim 13 or 14, wherein the difference is caused by being cut corresponding to a predetermined size.

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