Image formation 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] The present disclosure relates to a paper discharge device, a paper discharge method, and an image forming system. [Background technology]

[0002] Conventionally, there is known an image forming apparatus that forms an image on a recording medium, that is, paper, and outputs the image. 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 feed section, and the sheets are fed one by one in sequence to form the same image on the sheets (for example, see Patent Document 1). In such an image forming apparatus, a packaged stack of sheets of paper is often used. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-189419 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, although the paper in the package is manufactured to be the same size according to a common standard, the size of each sheet varies slightly, and for example, the size of the top sheet and the bottom sheet may differ greatly. This is because the sheets that make up the paper stack are cut from a single large sheet of paper, and there is an influence of error that occurs when cutting.

[0005] Therefore, when the same image is formed on each sheet of paper using such a paper stack, it is not possible to form an image of the quality desired by the user. Also, when a large amount of paper is output using paper from multiple paper stacks, there is a possibility that the ejected paper will be significantly misaligned and the paper will not be properly aligned.

[0006] The present disclosure has been made in consideration of the problems in the above-mentioned conventional technology, and aims to provide a paper discharge device, a paper discharge method, and an image forming system that can appropriately align the size of output paper. [Means for solving the problem]

[0007] The paper discharge device according to the present disclosure is A reading unit that acquires a reading size, which is the size of the recording medium; a paper discharge unit that purges recording media whose size difference value, which is a difference value between the read size and a preset reference size, is greater than an allowable value; Equipped with.

[0008] The paper ejection method according to the present disclosure includes: Obtain the read size, which is the size of the recording medium; A recording medium having a size difference value between the read size and a preset reference size that is greater than a tolerance value is purged.

[0009] The image forming system according to the present disclosure includes: The above-mentioned paper discharge device, an image forming apparatus for forming an image on the recording medium; Equipped with. Effect of the Invention

[0010] According to the present disclosure, the size of output paper can be appropriately adjusted. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a schematic diagram showing an example of the configuration of an image forming system according to the present embodiment. [Diagram 2] FIG. 2 is a block diagram showing a main part of a control system of the image forming system according to the present embodiment. [Diagram 3] FIG. 3 is a schematic diagram for explaining the paper size of a paper stack. [Figure 4]FIG. 4 is a flowchart showing an example of the flow of the correction coefficient calculation process performed by the image forming system according to the present embodiment. [Diagram 5] FIG. 5 is a schematic diagram showing an example of an actual size setting screen displayed on the operation display unit. [Figure 6] FIG. 6 is a flowchart showing an example of the flow of the purge process by the image forming system according to the present embodiment. [Figure 7] FIG. 7 is a schematic diagram showing an example of a purge setting screen for setting the difference deviation amount and the number of consecutive NG sheets, which is displayed on the operation display unit. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[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 are possible without departing from the spirit of the present disclosure. In addition, in each drawing, the same reference numerals are used to denote the same or equivalent parts, and this is common throughout the entire specification.

[0013] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An image forming system according to an embodiment of the present disclosure is capable of forming an image on a sheet of paper (recording medium), such as a paper sheet.

[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. Fig. 2 is a block diagram showing the main parts of a 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 device 100, a paper feed section 200, a reading section 300, an upstream paper discharge section 600, and a downstream paper discharge section 400. The reading section 300 and the upstream paper discharge section 600 or the downstream paper discharge section 400 constitute a paper discharge device according to the present embodiment.

[0015] The image forming apparatus 100 is an intermediate transfer type color image forming apparatus that utilizes electrophotographic process technology. That is, the image forming apparatus 100 primarily transfers the toner images of each color, CMYK, formed on a photoconductor onto an intermediate transfer body, and then superimposes the four color toner images on the intermediate transfer body, and then secondarily transfers them onto paper to form an image. CMYK stands for C (cyan), M (magenta), Y (yellow), and K (black).

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

[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 transport unit 40, an operation display unit 50, a communication unit 71, a memory unit 72, a control unit 500, a paper feeding unit 200, a reading unit 300, an upstream paper discharge unit 600, and a downstream paper discharge unit 400.

[0018] The image processing unit 10 includes a circuit for performing image processing on input image data according to initial settings or user settings, etc. The image forming unit 20 is controlled based on the image data that has been subjected to the image processing.

[0019] The image forming section 20 includes an image forming unit 21, an intermediate transfer unit 22, and a secondary transfer unit 23. The image forming unit 21 forms an image using color toners of each color component based on image data from the image processing section 10. For example, the image is formed using color toners 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 photosensitive drum, a charging device, a drum cleaning device, etc. Since known technologies can be adopted for the exposure device, the developing device, the photosensitive drum, the charging device, and the drum cleaning device, detailed description thereof will be omitted here.

[0021] The intermediate transfer unit 22 includes an intermediate transfer belt and the like. The intermediate transfer belt is stretched in a loop shape around a number of support rollers and travels in the direction of arrow A. The support rollers include a backup roller, a primary transfer roller, a drive roller, and other rollers, but these are not shown here. The intermediate transfer belt is pressed against the photosensitive drum, thereby transferring a toner image from the photosensitive drum to the intermediate transfer belt.

[0022] The intermediate transfer unit 22 may be configured to include a belt cleaning device having a plate-shaped belt cleaning blade or the like that is in sliding contact with the surface of the intermediate transfer belt. The belt cleaning device removes residual toner and the like that remains on the surface of the intermediate transfer belt after the secondary transfer.

[0023] The secondary transfer unit 23 includes a secondary transfer roller, etc. The secondary transfer roller is in pressure contact with the intermediate transfer belt, so that 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 paper is transported to the secondary transfer nip, the toner images of each color carried on the intermediate transfer belt are transferred onto the paper at once. The paper onto which the toner images have been transferred is transported toward the fixing unit 30 by the secondary transfer roller.

[0025] Incidentally, the secondary transfer unit 23 may be a belt-type secondary transfer unit having a secondary transfer belt stretched 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 and a pressure roller. The fixing roller is heated to a predetermined fixing temperature, and the pressure roller forms a fixing nip between the fixing roller and the pressure roller to sandwich and transport the paper. In the fixing unit 30, the toner image is fixed to the paper by heating and pressurizing the paper, which has been secondarily transferred and transported, in the fixing nip.

[0027] The paper transport section 40 includes a transport path section 41. The transport path section 41 is composed of, for example, a path for transporting the paper, a plurality of transport rollers, and a drive motor for driving the transport rollers to rotate. The transport path section 41 transports the paper supplied from the paper feed section 200 to the secondary transfer unit 23 and the fixing section 30, and then transports the paper to the downstream paper discharge section 400.

[0028] In the transport path section 41, a registration roller pair 41a is provided upstream of the secondary transfer unit 23 in the paper transport direction D. The registration roller pair 41a adjusts the transport timing and direction (angle) of the paper transported 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, and functions as a display unit and an operation unit. The display unit displays various operation screens, image status display, and operation status of each function according to a display control signal input from the control unit 500. The operation unit includes various operation keys such as a numeric keypad and a start key, and outputs operation signals to the control unit 500 upon receiving various input operations by the user.

[0030] The paper feed unit 200 is disposed upstream of the image forming apparatus 100 in the paper transport direction D, and is connected to the image forming apparatus 100 via a reading unit 300 and an upstream paper discharge unit 600, which will be described later. The paper feed unit 200 has a plurality of paper feed trays 201, 202, and 203, and each of the paper feed trays 201, 202, and 203 stores sheets of paper (standard paper or special paper) identified based on basis weight or size, etc., for each preset type. The paper feed unit 200 supplies the specified paper to the image forming apparatus 100 based on an instruction from the image forming apparatus 100.

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

[0032] Reading unit 300 has sensors 301 and 302 that read the paper transported from paper feed unit 200. Sensor 301 is disposed above the path along which the paper is transported, facing the paper being transported, and configured to read the front (upper) side of the paper being transported. Sensor 302 is disposed below the path along which the paper is transported, facing the paper being transported, and configured to read the back (lower) side of the paper being transported.

[0033] For example, CCDs (Charge Coupled Devices) or CISs (Contact Image Sensors) are used as the sensors 301 and 302. Also, for example, line sensors extending over a width equal to or greater than the width of the paper (width in a direction perpendicular to the paper transport direction D) such as a line scanner or a line sensor camera are used as the sensors 301 and 302.

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

[0035] Here, as an example, the reading unit 300 is configured to have sensors 301 and 302 that read both sides (front and back) of the paper, but this is not limited to this and may be configured to have, for example, only sensor 301 that reads one side (front) of the paper.

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

[0037] For example, when the paper size satisfies a predetermined condition, the upstream paper ejection section 600 conveys the paper to the image forming apparatus 100. When the paper size does not satisfy the predetermined condition, the upstream paper ejection section 600 ejects the paper to the purge tray 601 as shown by the dashed arrow in Fig. 1. In this embodiment, when the size of the paper read by the reading section 300 does not fit within the predetermined size, the upstream paper ejection section 600 ejects the paper to the purge tray 601.

[0038] Note that, here, as an example, the image forming system 1 is configured to include the upstream paper discharge section 600, but may be configured not to include the upstream paper discharge section 600. In such a configuration, when the paper size does not satisfy a predetermined condition based on the result of reading the paper by the reading section 300, the image forming section 20 does not form an image (hereinafter, appropriately referred to as "printing"), and the paper is transported to the downstream paper discharge section 400 by the paper transport section 40.

[0039] The downstream discharge section 400 is disposed downstream of the image forming apparatus 100 in the paper transport direction D, and is connected to the image forming apparatus 100. The downstream discharge section 400 has a paper output tray 401 and a purge tray 402, and discharges paper transported from the image forming apparatus 100 to the paper output tray 401 or the purge tray 402.

[0040] The paper output tray 401 outputs paper on which an image has been formed by the image forming apparatus 100. The purge tray 402 outputs paper whose paper size does not satisfy a predetermined condition as a result of the paper size being read by the reading unit 300. For example, if the paper size read by the reading unit 300 does not satisfy a predetermined condition, the downstream paper output unit 400 may output paper on which an image has not been formed by the image forming apparatus 100 from the purge tray 402, as indicated by the dashed-dotted arrow in FIG.

[0041] The control unit 500 is connected to the above-mentioned image processing unit 10, image forming unit 20, fixing unit 30, paper transport unit 40, operation display unit 50, communication unit 71, memory unit 72, paper feed unit 200, reading unit 300, upstream paper discharge unit 600, and downstream paper discharge unit 400. The control unit 500 issues various instructions to each of these units and executes predetermined processes.

[0042] In this embodiment, the control unit 500 performs a correction coefficient calculation process to calculate a correction coefficient for correcting the size of the paper read by the reading unit 300. Furthermore, the control unit 500 performs a purge process to purge the paper if the size of the paper is not the desired size. The correction coefficient calculation process and the purge process will be described in detail later.

[0043] The control unit 500 includes a central processing unit (CPU) 501, a read only memory (ROM) 502, and a random access memory (RAM) 503. The CPU 501 reads out a program corresponding to the processing contents from the ROM 502, loads it in the RAM 503, and centrally controls the operation of each block of the image forming system 1 in cooperation with the loaded program. At this time, various data such as a look up table (LUT) stored in the storage unit 72 is referenced. The storage unit 72 is configured, for example, with a non-volatile 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 a 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 a sheet based on this image data (input image data). The communication unit 71 is, for example, configured from a communication control card such as a LAN card.

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

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

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

[0048] In addition, the calculation unit calculates a corrected paper size by correcting the read size based on the read size and the calculated correction coefficient during the purge process. Furthermore, the calculation unit calculates a size difference value that is the absolute value of the difference between the calculated corrected paper size and the standard paper size.

[0049] The comparison unit, for example, compares the size difference value calculated by the calculation unit with the difference deviation amount, and determines whether or not to purge the paper based on the comparison result. The difference deviation amount is a tolerance value for the size difference value, and indicates the allowable deviation amount of the corrected paper size from the reference paper size.

[0050] The comparison unit also compares the count value of 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 that becomes the criterion for canceling the job when paper is purged consecutively.

[0051] [Operation of image forming system 1] In image forming system 1 according to the present embodiment having the above configuration, when an image is formed on paper as a recording medium, the paper is stored in paper feed trays 201, 202, and 203 of paper feed unit 200. The paper fed from paper feed unit 200 is then transported to image forming device 100, where it is printed, and transported to downstream paper discharge unit 400.

[0052] When forming images on a large amount of paper, the paper feed trays 201, 202, and 203 often contain packaged bundles of paper. In this case, even if the packaged paper is of the same standard, the paper size may differ from the expected size. This is because the paper in the bundle is cut from a larger sheet, and there is an effect of an error that occurs when cutting.

[0053] Fig. 3 is a schematic diagram for explaining the paper size of a paper stack. Fig. 3 shows an example of a paper stack when the paper is viewed from a direction perpendicular to the conveying direction. This example shows a state in which two packaged paper stacks are stacked.

[0054] This example shows a situation where there is an error of about 1 mm between the size of the topmost sheet and the size of the bottommost sheet for each stack of sheets. This error occurs because when a large sheet of paper is cut, it is not cut perpendicular to the surface, but at a certain angle. In this case, the size gets smaller from the top to the bottom of the stack of sheets, and if the topmost sheet is cut to comply with the standard, the bottommost sheet will be about 1 mm shorter than the standard size.

[0055] In this way, when an image is printed on paper of a size different from the size specified by the standard, the printing may not be performed properly, and the user may not be able to obtain the quality of the printed matter that he or she desires. Also, when a large amount of printed matter is output using paper from multiple paper stacks, the ejected paper may be significantly misaligned, and the paper may not be aligned properly.

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

[0057] On the other hand, the paper size read by the reading unit 300 may differ 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 occurs between the actual paper size and the read size, making it impossible to read the paper size accurately.

[0058] Therefore, 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-mentioned purge process when a job is reserved or executed.

[0059] (Correction coefficient calculation process) 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 actual size of the paper is measured in advance by the user. The actual size of the paper is measured manually, for example. At this time, the user may, for example, take out the topmost sheet of paper from a package of sheets of paper to be used for printing, and measure the size of the taken-out sheet. Also, without being limited to this, the actual 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 operating 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 a reference paper size.

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

[0062] The transport direction size input box 52 is selected by a user's touch operation or the like when inputting a numerical value indicating the actual size of the paper in the transport direction. When the transport direction size input box 52 is selected, for example, numerical input buttons such as a numeric keypad are displayed on the operation display unit 50. Then, the user operates the numerical input buttons to input the actual size of the paper in the transport direction (transport direction size). In this example, a state in which "210.0 mm" has been input as the transport direction size is shown.

[0063] The transport direction intersecting size input box 53 is selected by a user's touch operation or the like when inputting a numerical value indicating the actual size of the paper in a direction intersecting the transport direction. When the transport direction intersecting size input box 53 is selected, for example, numerical input buttons such as a numeric keypad are displayed on the operation display unit 50. Then, the user operates the numerical input buttons to input the actual size of the paper in a direction intersecting the transport direction (transport direction intersecting size). In this example, a state in which "297.0 mm" has been input as the transport direction intersecting size is shown.

[0064] The measurement start button 54 is selected by the user when reading the paper size by the reading unit 300. By operating the measurement start button 54, the reading unit 300 starts measuring the paper size.

[0065] When the measurement start button 54 displayed on the actual 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 obtains 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 standard paper size stored in the storage unit 72. Then, the calculation unit of the control unit 500 calculates the reading error based on the standard paper size, which is the actual size of the paper, and the size read by the reading unit 300.

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

[0068] Therefore, when the size of the paper on which an image is printed is 209.5 mm as read by the reading unit 300, the actual paper size is "209.5 x 210 / 209.5 = 210 mm", and it is found 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] This correction coefficient calculation process is performed for each type of paper classified by standard, and the correction coefficient is calculated according to the type of paper. As a result, the corrected paper size is calculated using the correction coefficient corresponding to each type of paper, so that the size of the scanned paper can be appropriately corrected.

[0071] Depending on the job reserved or executed, multiple types of paper such as A4 size and A3 size may be 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 paper of each type in the job.

[0072] (Purge process) Next, the purge process will be described with reference to a flow chart of 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 number of consecutive NG sheets are input by a user's operation on the operation display unit 50. The operation display unit 50 supplies information including the difference deviation amount and the number of consecutive NG sheets input by the user to the control unit 500. The control unit 500 stores and sets the difference deviation amount and the number of consecutive NG sheets included in the received information in the storage unit 72.

[0074] The reason for setting the number of consecutive NG sheets here is to prevent a large number of sheets from being purged. For example, if it is assumed that the size of the sheets in a stack of sheets changes from top to bottom as shown in Fig. 3, when a certain number of sheets are purged in succession, there is a high possibility that the subsequent sheets 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 number of consecutive NG sheets, which is displayed on the operation display unit 50. As shown in Fig. 7, the operation display unit 50 displays the purge setting screen 55 including a difference deviation amount input box 56 and a consecutive NG sheet number input box 57.

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

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

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

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

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

[0081] In step S16, the calculation unit reads out the standard paper size stored in the memory unit 72, and calculates a size difference value that is the absolute value of the difference between the standard paper size and the corrected paper size. Next, the comparison unit of the control unit 500 compares the size difference value with the differential shift amount set in step S11. If the comparison result shows that the size difference value is equal to or smaller than the differential shift amount (step S16: NO), the process proceeds to step S17.

[0082] In step S17, the paper whose size difference value is determined to be equal to or less than the differential deviation amount is transported from the reading unit 300 to the image forming apparatus 100 via the upstream paper ejection unit 600. The control unit 500 forms an image on the paper transported to the image forming apparatus 100. The paper on which the image has been formed is transported to the downstream paper ejection unit 400 and ejected from the paper ejection 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 judges whether the sheet discharged to the discharge tray 401 in step S17 is the last sheet of the job. If the judgment result is that the sheet is the last sheet (step S19: YES), the series of processes ends. On the other hand, if the sheet is not the last sheet (step S19: NO), the process returns to step S13.

[0085] On the other hand, if the size difference value is greater than the differential shift amount in step S16 (step S16: YES), the process proceeds to step S20. If the size difference value is determined to be greater than the differential shift amount in step S20, the paper is transported from the reading unit 300 to the upstream paper ejection unit 600 and is purged by being ejected from the purge tray 601.

[0086] If the image forming system 1 is not provided with the upstream discharge section 600, the paper for which it is determined that the size difference value is larger than the differential deviation amount may be discharged from the downstream discharge section 400. In this case, the paper is transported from the reading section 300 to the image forming apparatus 100, but is transported to the downstream discharge section 400 without an image being formed on the paper in the image forming apparatus 100. The paper transported to the downstream discharge section 400 is then purged by being discharged from the purge tray 402.

[0087] In step S21, the control unit 500 increments the count value of the counter 505 for the number of consecutive NG sheets by one.

[0088] In step S22, the control unit 500 compares the count value of the counter 505 indicating the number of consecutive NG sheets with the set value of the number of consecutive NG sheets, and judges whether the count value is greater than the set value. If the comparison result shows that the count value of the number of consecutive NG sheets is greater than the set value (step S22: YES), the control unit 500 judges that the number of consecutive NG sheets has exceeded the allowable number. In this case, the control unit 500 cancels the current job. Then, the series of processes ends.

[0089] On the other hand, if the count value is equal to or less than the set value (step S22: NO), the control unit 500 determines that the number of consecutive NG sheets does not exceed the allowable number, and the process returns to step S13.

[0090] The purge process is performed after the correction coefficient is calculated by the above-mentioned correction coefficient calculation process. However, if there is no need to correct the paper size, the purge process may be performed without performing the correction coefficient calculation process. In this case, after the paper size is read in step S14, the calculation unit of the control unit 500 calculates the absolute value of the difference between the standard paper size and the read size as a size difference value in step S16.

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

[0092] Furthermore, the calculation unit of the control unit 500 calculates a correction coefficient for correcting the size of the paper read by the reading unit 300, and calculates a corrected paper size by correcting the read size using the correction coefficient. This causes the read size read by the reading unit 300 to be corrected to the actual paper size. Therefore, the image forming system 1 can accurately obtain the size of the paper. [Explanation of symbols]

[0093] 1. Image forming system 50 Operation display section 51 Actual size setting screen 52 Conveying direction size input box 53 Conveyance direction cross size input box 54 Measurement start button 55 Purge setting screen 56 Differential deviation input box 57 Continuous NG count input box 100 Image forming device 200 Paper feed section 201, 202, 203 Paper Tray 300 Reading unit 301, 302 Sensor 400 Downstream paper output section 401 Output tray 402, 601 Purge Tray 500 Control section 505 Counter 600 Upstream paper discharge section

Claims

1. A reading unit that acquires a reading size, which is the size of the recording medium; a paper discharge unit that purges recording media whose size difference value, which is a difference value between the read size and a preset reference size, is greater than an allowable value; A paper discharge device comprising:

2. The image forming apparatus further includes a calculation unit that calculates a correction coefficient, which is a reading error, based on the reading size and the reference size, and calculates a corrected size by correcting the reading size with the correction coefficient. The paper delivery device according to claim 1 .

3. The calculation unit is The reference size is divided by the reading size to calculate the correction coefficient. The paper delivery device according to claim 2 .

4. The calculation unit is A difference between the corrected size and the reference size is calculated as the size difference value. The paper delivery device according to claim 2 .

5. a comparison unit that compares the size difference value with the tolerance value, The comparison unit is purging the read recording medium if the size difference value is greater than the tolerance value; The paper delivery device according to claim 1 .

6. The tolerance value is further input to an operation unit. The paper delivery device according to claim 1 .

7. A counter is further provided for counting the number of sheets of the recording medium that are successively purged, When the recording medium has been purged a predetermined number of times in succession, the job is stopped. The paper delivery device according to claim 1 .

8. The tolerance is: a difference in deviation amount indicating an allowable deviation amount of the reading size from the reference size; The paper delivery device according to claim 1 .

9. Obtain the read size, which is the size of the recording medium; A recording medium having a size difference value between the read size and a preset reference size that is greater than a tolerance value is purged. Paper ejection method.

10. The paper ejection device according to claim 1 ; an image forming apparatus for forming an image on the recording medium; An image forming system comprising:

Images