Printing system

Abstract

To reduce the number of pages whose print positions are not adjusted, compared to when the print positions of pages of a print job are adjusted on the basis of position adjustment images of multiple pages of the print job.SOLUTION: A printing system includes a printing unit that prints a print job and prints position adjustment images corresponding to each page of the print job, a reading unit that reads the position adjustment images printed by the printing unit, and an adjustment unit that adjusts the printing position of the pages of the print job printed by the printing unit on the basis of the position adjustment images read by the reading unit, and adjusts the printing position of the smallest page whose printing position can be adjusted from the second page onwards of the print job on the basis of the position adjustment image of the first page of the print job.SELECTED DRAWING: Figure 9

Description

[Technical Field]

[0001] The present invention relates to a printing system. [Background technology]

[0002] Patent Document 1 discloses an image forming apparatus having a print image forming unit that forms an image and prints the image on a transfer medium, and a control unit that manages jobs and controls image formation in the image forming unit, wherein the control unit has a real-time adjustment function that prints an adjustment image on the transfer medium and obtains the reading results of the adjustment image while the image forming unit is outputting a job in which the image is printed on the transfer medium based on the job, and adjusts the image quality of the image formed in the image forming unit in real time based on the reading results, and when an executed job includes a job that does not perform real-time adjustment and a job that does perform real-time adjustment, the control unit prints an adjustment image on the transfer medium for the job that does not perform real-time adjustment and obtains the reading results, and applies image quality adjustment to the job that performs real-time adjustment based on the reading results. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 2018-010115 Summary of the Invention [Problem to be solved by the invention]

[0004] The present invention aims to reduce the number of pages whose print positions are not adjusted, compared to when the print positions of pages of a print job are adjusted based on position adjustment images of multiple pages of the print job. [Means for solving the problem]

[0005] The printing system according to the first aspect includes: a printing unit that prints a print job and prints a position adjustment image corresponding to each page of the print job; a reading unit that reads the position adjustment image printed by the printing unit; an adjustment unit that adjusts the print position of the pages of the print job printed by the printing unit based on the position adjustment image read by the reading unit, and adjusts the print position of the smallest page whose print position can be adjusted for the second and subsequent pages of the print job based on the position adjustment image of the first page of the print job; The present invention is characterized by having the following.

[0006] A printing system according to a second aspect is the printing system according to the first aspect, The adjustment unit is characterized in that each time it reads the position adjustment image for the second page or later of the print job, it adjusts the printing position of the page to be printed after adjusting the correction value based on the correction value adjusted using the read position adjustment image.

[0007] A printing system according to a third aspect is the printing system according to the second aspect, The adjustment unit calculates positional deviation information of the position adjustment image for each page based on the position adjustment image, and adjusts the printing position of the page based on an averaging value obtained by averaging the calculated positional deviation information according to the number of times the position adjustment image is read.

[0008] A printing system according to a fourth aspect is the printing system according to the third aspect, When the number of times of reading exceeds a predetermined upper limit, the adjustment unit averages the positional deviation information in accordance with the upper limit. [Effects of the Invention]

[0009] According to the first aspect, it is possible to reduce the number of pages whose print positions are not adjusted, compared to when the print positions of pages of a print job are adjusted based on position adjustment images of multiple pages of the print job.

[0010] According to the second aspect, the accuracy of adjusting the print position of a page can be improved compared to when the print positions of all pages whose print positions can be adjusted are adjusted based on the position adjustment image of the first page of the print job.

[0011] According to the third aspect, the accuracy of adjusting the print position of a page can be improved compared to when the print positions of all pages whose print positions can be adjusted are adjusted based on the position adjustment image of the first page of a print job.

[0012] According to the fourth aspect, the averaging process time can be reduced compared to when all calculated positional deviation information is averaged. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a diagram illustrating a schematic configuration of a printing system according to an embodiment. [Figure 2] FIG. 1 is a plan view showing a printed matter on which a position adjustment image is printed according to an embodiment. [Figure 3] FIG. 10 is an explanatory diagram illustrating the operation of a printing system that starts printing subsequent printed materials before reading a position adjustment image from the first page of printed material. [Figure 4] 4 is a graph showing the relationship between the number of printed sheets of printed matter and the amount of positional deviation of the position adjustment image M read from the printed matter by the image reader in the printing system shown in FIG. 3. [Figure 5] 10 is an explanatory diagram illustrating the operation of a printing system that calculates a moving average value of a plurality of pieces of positional deviation information and calculates a correction value for the printing position of a print image based on the calculated moving average value. FIG. [Figure 6] 6 is a graph showing the relationship between the number of printed sheets of printed matter and the amount of positional deviation of an image read from the printed matter by an image reader in the printing system shown in FIG. 5. [Figure 7] FIG. 2 is a block diagram showing the hardware configuration of the printing system shown in FIG. [Figure 8] FIG. 2 is a functional block diagram of the printing system shown in FIG. [Figure 9] 4 is a flowchart showing the flow of a print position adjustment process in the printing system shown in FIG. [Figure 10] 2 is an explanatory diagram illustrating feedback control of the print position of a print image printed on paper in the printing system shown in FIG. 1. FIG. [Figure 11] 10 is a graph showing the relationship between the number of printed sheets and the amount of misalignment or the correction value. [Figure 12] 10 is a graph showing the relationship between the number of printed sheets and the amount of misalignment or the correction value. [Figure 13] 10 is a graph showing the relationship between the number of printed sheets and the amount of misregistration. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, an embodiment will be described with reference to the drawings.

[0015] (Printing Device Overview) 1 shows a printing system 10 according to one embodiment. The printing system 10 includes a printing machine 20 and an image reader 30.

[0016] (printing machine) The printing machine 20 has a plurality of storage trays 20T for storing paper sheets. The printing machine 20 also has a printing function for printing an image (hereinafter referred to as a "printed image") on paper sheets supplied from the storage trays 20T. The printing machine 20 supplies the paper sheets on which the printed image has been printed (hereinafter referred to as a "printed matter") to the image reader 30. The paper sheets are an example of a recording medium.

[0017] (Image reader) The image reader 30 has an image reading function of sequentially receiving printed materials on which print images have been printed from the printer 20 and reading the printed images from the received printed materials. Specifically, the image reader 30 has a scanner or the like as an inline sensor that optically reads the printed images from the printed materials received from the printer 20. The image reader 30 also has an output tray 30A onto which the printed materials from which the print images have been read are discharged.

[0018] (Print position adjustment function) The printing system 10 has a print position adjustment function that adjusts the position of a print image printed on paper. In a printing process that executes this print position adjustment function, a print image (hereinafter referred to as a "position adjustment image") is printed on the paper to detect the print position of the print image printed on the paper. The position adjustment image is printed, for example, in the margin area of ​​the paper to be cut.

[0019] 2 shows an example of a position adjustment image M. As an example, the position adjustment image M is a cross-shaped image, and is printed at each of the four corners of the margin area outside the image printing area R on the paper P. Furthermore, each position adjustment image M is printed so as to be positioned at a predetermined position (hereinafter referred to as a "target position") on the paper P. As an example, the target position of the position adjustment image M may be a predetermined distance (hereinafter referred to as a "target distance X, Y") from the outer periphery of the paper P.

[0020] In double-sided printing, in which a print image is printed on both sides of the paper P, a plurality of position adjustment images M are printed on both sides of the paper P, respectively.

[0021] Each position adjustment image M printed on the paper P is read by the image reader 30. Then, the position of the position adjustment image M relative to the paper P (hereinafter referred to as the "detection position") is detected by performing image analysis on the position adjustment image M read by the image reader 30. The detected position of the position adjustment image M relative to the paper P can be, for example, the distance from the outer edge of the paper P to the position adjustment image M (hereinafter referred to as the "detection distance x, y"). Based on this detected position and the target position described above, positional deviation information of the position adjustment image M is calculated.

[0022] Examples of the misalignment information include the lead position, side position, right-angle correction amount, trapezoidal correction amount, horizontal magnification (main scanning magnification), and vertical magnification (sub-scanning magnification). As an example, the lead position is the amount of misalignment of the position adjustment image M in the transport direction of the paper P, and is calculated as, for example, the difference (Xx) between the target distance X and the detected distance x. Furthermore, the side position is the amount of misalignment of the position adjustment image M in a direction perpendicular to the transport direction of the paper P, and is calculated as, for example, the difference (Yy) between the target distance Y and the detected distance y.

[0023] Next, based on the calculated misalignment information, a correction value is calculated to adjust the print position of the print image to be printed on the paper P. As an example, the correction value is calculated for each type of misalignment information (lead position, side position, right angle correction amount, trapezoidal correction amount, horizontal magnification, vertical magnification) described above.

[0024] For example, the lead position correction value is calculated as position information indicating the print start position of the print image based on the leading edge in the transport direction of the paper P. Also, for example, the side position correction value is calculated as position information indicating the print start position of the print image based on one edge in the direction perpendicular to the transport direction of the paper P. Then, based on the calculated correction value, the printing position of the print image to be printed on the paper P is adjusted in the printing press 20.

[0025] (Correction continuous printing function) Here, when multiple printed materials are continuously printed in the printing system 10, the print position of the printed image is likely to shift due to the influence of factors such as a rise in temperature of the transport mechanism that transports the paper, and the amount of shift in the print position of the printed image is likely to change depending on the temperature of the transport mechanism. Therefore, the printing system 10 according to this embodiment is equipped with a correction continuous printing function (real-time correction continuous printing function) that adjusts the position of the print image printed on the paper while continuously printing multiple printed materials.

[0026] In a print job using the corrected continuous printing function, while multiple printed materials are printed continuously, the printing position of the printed image is adjusted by feedback control based on the position adjustment image printed on the preceding printed material.

[0027] Specifically, as shown in the schematic diagram of Fig. 3, the printing system 10 prints the above-mentioned position adjustment images (see Fig. 2) in the margin area of ​​the paper in the printing machine 20. Then, the printing system 10 reads the position adjustment images in order from the preceding printed matter using the image reader 30, and calculates positional deviation information for each of the position adjustment images relative to the paper based on the read position adjustment images.

[0028] Then, the printing system 10 calculates a correction value for adjusting the printing position of the print image based on the calculated positional deviation information, and adjusts the printing position of the print image to be printed on paper in the printing press 20 based on the calculated correction value. This reduces the amount of positional deviation of the print image printed on paper while continuously printing multiple printed materials.

[0029] 3, before the image reader 30 reads the position adjustment image from the first page (1p) of the print job, the printer 20 starts printing the subsequent second page (2p) and subsequent printed materials. Therefore, in the printing system 10 shown in FIG. 3, the printing position of the print image is not adjusted when the first to fourth pages (1-4p) of the print job are printed, but is adjusted from the fifth page (5p) onwards.

[0030] 4 shows a graph illustrating the relationship between the number of printed sheets of printed matter and the amount of misalignment of the position adjustment image read from the printed matter by the image reader 30 in the printing system 10 shown in FIG. 3. The amount of misalignment of the position adjustment image (misalignment information) is, for example, the amount of misalignment of the position adjustment image in the paper transport direction (registration position).

[0031] As shown in Figure 4, the amount of misalignment of the position adjustment images is large in printed materials from pages 1 to 4 (1 to 4p), where the printing position of the printed image is not adjusted, and the amount of misalignment of the position adjustment images is small in printed materials from page 5 (5p) onwards, where the printing position of the printed image is adjusted.

[0032] If printing of the subsequent printed material is started before the position adjustment image is read from the preceding printed material in this way, multiple printed materials will be generated in which the printing position of the print image is not adjusted.

[0033] (Measures to prevent variations in positional deviation information) Here, in order to reduce the variation in the positional deviation information of the printed image, it is conceivable to calculate a moving average value of multiple pieces of positional deviation information and calculate a correction value for the printing position of the printed image based on the calculated moving average value.

[0034] 5, the misalignment information of the position adjustment image is the moving average value of 16 printed sheets. In this case, if the number of times the position adjustment image is read from the printed sheets in the image reader 30 (hereinafter referred to as the "number of reads") does not reach the number required to calculate the moving average of the misalignment information, i.e., 16 times, the misalignment information is not calculated and the printing position of the print image is not adjusted in the printer 20.

[0035] 5, printing of the subsequent printed matter from page 17 (17p) onwards is started in the printing press 20 before the correction value is calculated. Therefore, in the printing system 10 shown in Fig. 5, the printing position of the printed image is not adjusted when printing pages 1 to 19 (1 to 19p), but is adjusted from page 20 (20p) onwards.

[0036] Fig. 6 shows a graph illustrating the relationship between the number of printed sheets of printed matter and the amount of misalignment of the position adjustment image read from the printed matter by the image reader 30 in the printing system 10 shown in Fig. 5. Note that the amount of misalignment of the position adjustment image (misalignment information) is, for example, the amount of misalignment of the position adjustment image in the paper transport direction (registration position).

[0037] As shown in Figure 6, the amount of misalignment of the position adjustment images is large in printed materials from pages 1 to 19 (1 to 19p), where the printing position of the printed image is not adjusted, and the amount of misalignment of the position adjustment images is small in printed materials from page 20 (20p) onwards, where the printing position of the printed image is adjusted.

[0038] If moving average values ​​of multiple pieces of positional deviation information are calculated in this way and a correction value for the printing position of the print image is calculated based on the calculated moving average values, the number of printed materials in which the printing position of the print image is not adjusted will increase.

[0039] Therefore, in the printing system 10 according to this embodiment, the printing position of the smallest page for which the printing position can be adjusted is adjusted for the second and subsequent pages of the print job based on the position adjustment image of the first page of the print job. The printing system 10 according to this embodiment will be described in detail below.

[0040] (Hardware configuration of the printing device) First, we will explain the hardware configuration of the printing system 10. Note that, for the sake of convenience, the hardware configuration of the printing system 10 will be explained below, but the printing machine 20 and the image reader 30 may each have a hardware configuration such as that shown in FIG.

[0041] 7, the printing system 10 includes a CPU (Central Processing Unit) 50, a ROM (Read Only Memory) 52, a RAM (Random Access Memory) 54, a storage 56, an input unit 58, a display unit 60, a communication interface (I / F) 62, an image reading unit 64, an image forming unit 66, and a position adjustment image reading unit 68. Each of the components is connected to each other via a bus 72 so as to be able to communicate with each other.

[0042] The CPU 50 is a central processing unit that executes various programs and controls each part. That is, the CPU 50 reads programs from the ROM 52 or storage 56 and executes the programs using the RAM 54 as a work area. The CPU 50 controls each of the above components and performs various arithmetic processing in accordance with the programs recorded in the ROM 52 or storage 56. The CPU 50 is an example of an adjustment part and a processor.

[0043] The ROM 52 stores various information processing programs and various data. The RAM 54 serves as a work area for the CPU 50 and temporarily stores programs or data.

[0044] The storage 56 is configured by a hard disk drive (HDD) or a solid state drive (SSD), and stores various programs including the operating system, and various data.

[0045] The input unit 58 includes operation buttons and the like and is used to perform various inputs. The display unit 60 is, for example, a liquid crystal display and displays various types of information. The display unit 60 may employ a touch panel system and function as an input unit.

[0046] The communication I / F 62 is an interface for communicating with other devices, and uses standards such as Ethernet (registered trademark), FDDI, and Wi-Fi (registered trademark).

[0047] The image reading unit 64 includes a scanner or the like, and optically reads image data from a document, etc. The image forming unit 66 prints the image data read by the image reading unit 64 or image data received from an operation terminal (not shown) onto a recording medium such as paper.

[0048] The position adjustment image reading unit 68 includes a scanner or the like, and optically reads a printed image such as a position adjustment image from a sheet of paper (printed matter) on which an image has been printed by the image forming unit 66.

[0049] (Printing Device Functions) Next, the functions of the printing system 10 will be described.

[0050] When executing the information processing program described above, the printing system 10 uses the above hardware resources to realize various functions of the printing machine 20 and the image reader 30.

[0051] (printing machine) Specifically, as shown in FIG. 8, the printing machine 20 functionally includes a print request receiving unit 22, a printing unit 26, an adjustment unit 27, and a print control unit 28.

[0052] (Print request reception unit) The print request receiving unit 22 receives a print job for corrected continuous printing input to the printing system 10. This print job includes, for example, print image information (print data), paper size, number of copies, and other printing conditions.

[0053] (Printing Department) The printing unit 26 prints the print image (including the position adjustment image) on the paper based on the print request for corrected continuous printing received by the print request receiving unit 22. At this time, the printing unit 26 adjusts the position of the print image to be printed on the paper based on the correction value of the print position of the print image calculated by the correction value calculation unit 34, which will be described later.

[0054] (adjustment section) The adjustment unit 27 adjusts the print position of the print image to be printed on the paper based on a correction value for the print position of the print image calculated by a correction value calculation unit 34, which will be described later.

[0055] (Printing control unit) The print control unit 28 controls the overall operation of the printing machine 20. Furthermore, based on the print job accepted by the print request accepting unit 22, the print control unit 28 continuously prints multiple prints while adjusting the print position of the print image to be printed on the paper.

[0056] Specifically, the print control unit 28 controls a paper feed device (not shown) based on the print job accepted by the print request acceptance unit 22, and causes the device to sequentially supply multiple sheets of paper from the storage tray 20T to the printing unit 26. The print control unit 28 also transmits print data to be printed on the multiple sheets of paper to the printing unit 26. The print control unit 28 then causes the printing unit 26 to print a print image and a position adjustment image based on the print data on the multiple sheets of paper supplied from the storage tray 20T, and causes the printing unit 26 to sequentially supply the multiple printed sheets to the image reader 30.

[0057] (Image reader) The image reader 30 functionally comprises a reading unit 31, a positional deviation information calculation unit 32, a correction value calculation unit , and an image reading control unit .

[0058] (Reading unit) The reading unit 31 optically reads the position adjustment image from the printed matter printed by the printing unit 26.

[0059] (Positional deviation information calculation unit) The positional deviation information calculation unit 32 calculates the detected position of the position adjustment image by performing image processing on the position adjustment image read by the reading unit 31. Then, the positional deviation information calculation unit 32 calculates positional deviation information of the position adjustment image based on the calculated detected position of the position adjustment image and the target position.

[0060] As described above, the positional deviation information of the position adjustment image includes the lead position, side position, right-angle correction amount, trapezoidal correction amount, and lateral magnification. The positional deviation information of the position adjustment image calculated by the positional deviation information calculation unit 32 is stored in a predetermined storage area as time-series data according to the number of printed sheets.

[0061] (Correction value calculation section) The correction value calculation unit 34 calculates a correction value for the printing position of the print image to be printed on paper based on the misalignment information calculated by the misalignment information calculation unit 32. As described above, the correction value is calculated for each type of misalignment information (lead position, side position, right-angle correction amount, trapezoidal correction amount, horizontal magnification, vertical magnification).

[0062] Here, when the number of times the position adjustment image is read is one, the correction value calculation unit 34 calculates a correction value for the printing position of the print image based on the position shift information of the first page calculated by the position shift information calculation unit 32.

[0063] Furthermore, when the number of times the position adjustment image has been read exceeds one and is equal to or less than a predetermined upper limit, the correction value calculation unit 34 averages the plurality of pieces of positional deviation information according to the number of times the position adjustment image has been read, and calculates a correction value for the print position of the print image based on the averaged value. Examples of averaging include arithmetic mean, geometric mean, weighted mean, and exponential mean. The averaging may also include, for example, a process of removing outliers from the interval. The upper limit is an integer greater than the reference number (upper limit > reference number).

[0064] Furthermore, when the number of times the position adjustment image is read exceeds the upper limit, the correction value calculation unit 34 averages the multiple pieces of positional deviation information according to the upper limit, and calculates a correction value for the printing position of the print image based on the averaged result.

[0065] Here, for example, if the upper limit number is 10 times, the following occurs: That is, when the number of times the position adjustment image is read is 1, the positional deviation information calculation unit 32 calculates the positional deviation information based on the positional deviation image read from the first page of the printed material by the image reader 30. Then, the correction value calculation unit 34 calculates the correction value for the printing position of the printed image based on the positional deviation information of the first page calculated by the positional deviation information calculation unit 32.

[0066] Next, when the number of times the position adjustment image is read is two, the positional deviation information calculation unit 32 calculates the positional deviation information based on the positional deviation image read from the second page of the printed material by the image reader 30. Then, the correction value calculation unit 34 averages the positional deviation information of the first and second pages calculated by the positional deviation information calculation unit 32, and calculates a correction value for the printing position of the printed image based on the averaged value.

[0067] Next, when the number of times the position adjustment image is read is three, the positional deviation information calculation unit 32 calculates the positional deviation information based on the positional deviation image read from the third page of the printed material by the image reader 30. Then, the correction value calculation unit 34 averages the positional deviation information of the first to third pages calculated by the positional deviation information calculation unit 32, and calculates a correction value for the printing position of the printed image based on the averaged value.

[0068] In this way, when the number of times the position adjustment image is read ranges from 2 to 10 times, the correction value calculation unit 34 averages multiple pieces of positional deviation information while increasing the number of sections according to the number of times the position adjustment image is read, and calculates a correction value for the printing position of the print image based on the averaged averaging process.

[0069] Next, when the number of times the position adjustment image has been read is 11, that is, when the number of times the position adjustment image has been read exceeds the upper limit, the correction value calculation unit 34 averages the plurality of pieces of positional deviation information according to the upper limit. More specifically, the correction value calculation unit 34 averages (moving averages) the plurality of pieces of positional deviation information with the number of sections set to 10, which is the upper limit. In other words, the correction value calculation unit 34 averages the plurality of pieces of positional deviation information calculated by the positional deviation information calculation unit 32, from the most recent to the number of times corresponding to the upper limit.

[0070] The upper limit number of times can be changed as appropriate, and may be set to, for example, 2 times or more, 9 times or less, or 11 times or more.

[0071] Furthermore, when averaging multiple pieces of positional deviation information, the number of times the position adjustment image is read and the number of sections in the averaging process do not necessarily have to match; for example, if the position adjustment image is read four times, the number of sections in the averaging process may be three.

[0072] (Image reading control unit) The image reading control unit 38 controls the overall operation of the image reader 30. Specifically, the image reading control unit 38 causes the reading unit 31 to read the position adjustment image from the printed material, and causes the positional deviation information calculation unit 32 to calculate positional deviation information of the position adjustment image.

[0073] The image reading control unit 38 also causes the correction value calculation unit 34 to calculate a correction value for the printing position of the print image to be printed on paper in the printing press 20. The image reading control unit 38 then transmits the correction value calculated by the correction value calculation unit 34 to the print control unit 28.

[0074] The print control unit 28 and the image reading control unit 38 cooperate to control the overall operation of the print system 10 by transmitting and receiving information to and from each other.

[0075] (Printing device correction value calculation process) Next, the correction value calculation process performed by the printing system 10 will be described.

[0076] When a print job is executed in the printing system 10 and a position adjustment image is read from a printed material by the image reader 30, the correction value calculation process shown in Fig. 9 is executed. Note that the correction value calculation process is an example of a correction value calculation method.

[0077] First, in step S10, the CPU 50 adds 1 to the variable number of times the position adjustment image has been read. Note that the variable number of times the position adjustment image has been read is initialized (number of times read = 0) when the corrected continuous printing process is executed.

[0078] Next, in step S12, the CPU 50 calculates positional deviation information of the position adjustment image based on the position adjustment image read from the printed material by the image reader 30.

[0079] Next, in step S14, the CPU 50 determines whether the number of times the position adjustment image has been read is 1. If the CPU 50 determines that the number of times the position adjustment image has been read is 1, the CPU 50 proceeds to step S16.

[0080] Next, in step S16, the CPU 50 calculates a correction value for the print position of the print image based on the positional deviation information of the first page calculated in step S14, and ends the correction value calculation process.

[0081] Here, once the correction value is calculated, the CPU 50 adjusts the printing position of the print image to be next printed on paper based on the calculated correction value. Specifically, for the pages of the print job that are printed after the calculation of the correction value for the printing position of the print image, the CPU 50 adjusts the printing position of the image based on the correction value calculated in step S16. In other words, the CPU 50 adjusts the printing position of the smallest page whose printing position can be adjusted from the second page onwards of the print job based on the position adjustment image of the first page of the print job. In the example shown in FIG. 3, the CPU 50 adjusts the printing position of the fifth page (5p) of the print job based on the position adjustment image of the first page (1p) of the print job.

[0082] On the other hand, if the CPU 50 determines in step S14 that the number of times the position adjustment image has been read exceeds one, the process proceeds to step S18.

[0083] Next, in step S18, the CPU 50 determines whether the number of times the position adjustment image has been read is equal to or less than the upper limit. If the CPU 50 determines that the number of times the position adjustment image has been read is equal to or less than the upper limit, the CPU 50 proceeds to step S20.

[0084] Next, in step S20, the CPU 50 averages the plurality of pieces of positional deviation information according to the number of times the position adjustment image has been read, and calculates an averaged value. Specifically, the CPU 50 averages the plurality of pieces of positional deviation information calculated based on the position adjustment images read from the first time to the number of times the image has been read, and calculates an averaged value.

[0085] Next, in step S22, the CPU 50 calculates a correction value for the print position of the print image to be printed on the paper based on the averaging process value of the plurality of pieces of positional deviation information, and ends the correction value calculation process.

[0086] Here, after the correction value is calculated, the CPU 50 adjusts the printing position of the print image to be printed next on paper based on the calculated correction value. Specifically, for the page of the print job to be printed after the correction value is calculated, the CPU 50 adjusts the printing position of the print image to be printed on paper based on the correction value calculated in step S22.

[0087] On the other hand, if the CPU 50 determines in step S18 that the number of times the position adjustment image has been read exceeds the upper limit, the process proceeds to step S24.

[0088] Next, in step S24, the CPU 50 averages the plurality of pieces of positional deviation information according to the upper limit number of times the position adjustment image is read, and calculates an averaged value. Specifically, the CPU 50 averages the plurality of pieces of positional deviation information from the most recent to the upper limit number of times, and calculates an averaged value. Then, the CPU 50 proceeds to step S22 described above.

[0089] (feedback control) Here, feedback control of the printing position of the print image printed on the paper in the printing press 20 will be described.

[0090] As shown in FIG. 10, the amount of misalignment calculated based on the position adjustment image read from the m-th page of the printed matter (read count m) is expressed as r m , the correction value of the print position of the print image applied when printing the nth page (n>m) of the print is C n Then, the general correction value C using the moving average n+1 The update formula is as shown in the following formula (1).

number

[0091] Regarding the method of deriving the above formula (1), a general update formula for feedback control is the following formula (2).

number

[0092] In the above formula (2), the second term on the right side is the latest correction value C n The first term on the right side is the correction value C nThis correction value ΔC is simplified to the negative positional deviation amount r m This leads to the following equation (3).

number

[0093] In Fig. 11, the positional deviation r m , the moving average value of the positional deviation Average(r m ), correction value C n Graph r showing the relationship between the number of printed sheets and the amount of misalignment or correction value for m , Average(r m ), C n In FIG. 11, the positional deviation amount r m Moving average value of Average(r m ) is set to 10 (Z=10). Also, in FIG. 11, the gain G is set to 0.1 (G=0.1).

[0094] As shown in FIG. 11, the positional deviation r m However, in the above formula (1), when the number of printed sheets is small, the latest correction value C applied to the nth printed page n and the misregistration amount r based on the printed matter on the mth page. m The correction value C n+1 The error tends to be large.

[0095] Therefore, the above formula (1) is modified as in the following formula (4). Specifically, in the following formula (4), the correction value C applied to the n-th page of the printed matter is n Instead, the latest correction value C applied to the mth page of the printoutm and the misregistration amount r based on the printed matter on the mth page. m Based on the difference between n+1 As a result, the difference due to the phase difference between the first and second terms on the right side of the following formula (4) is reduced, so the correction value C n+1 The error becomes smaller.

number

[0096] In addition, since the difference between the first and second terms on the right side of the above equation (4) is small, the gain G (G=1) may be omitted as in the following equation (5).

number

[0097] FIG. 12 shows the displacement amount r m , positional deviation (r m -C m ), the moving average of the position deviation Average(r m -C m ), correction value C n Graph r showing the relationship between the number of printed sheets and the amount of misalignment or correction value for m , r m -C m , Average(r m -C m ), C n In FIG. 12, the positional deviation (r m -C m ) moving average value Average(r m -C m ) is set to 10 (Z=10).

[0098] As shown in FIG. 12, the positional deviation r m It can be seen that the positional deviation amount r in the above equation (5) converges to 0. m Graph of r m is the positional deviation amount r in the above formula (1).m Graph of r m In comparison with (see Figure 11), the amplitude of the vibration is smaller and converges to around 0 from a small number of printed sheets.

[0099] In addition, Figure 13 shows the moving average value (r m -C m ) When the number of sections Z is 1 and 10, the number of printed sheets and the amount of misalignment r m Graphs Z1 and Z10 are shown which show the relationship between the above and the allowable range of the misregistration amount. The allowable range of the misregistration amount is set appropriately depending on, for example, the print quality of the printed matter.

[0100] As shown in FIG. 13, the positional deviation amount r m The deviation of the position r m In addition, in graph Z1, the positional deviation amount r m In other words, the graph Z1 reduces the number of printed sheets in which the print position of the print image is not adjusted compared to the graph Z10.

[0101] For these reasons, it is preferable to set the number of sections Z of the moving average of the misalignment amount small at the start of printing of the printed matter and to set it large as the number of printed matters increases. This suppresses misalignment of the printed image on the printed matter while reducing the number of printed matters in which the printing position of the printed image is not adjusted.

[0102] In the printing system 10 according to the embodiment, any of the above formulas (1), (4), and (5) can be used. In addition, in the printing system 10 according to the embodiment, other formulas may be used in addition to the above formulas (1), (4), and (5).

[0103] (Variation) Next, a modification of the above embodiment will be described.

[0104] In the above embodiment, when the number of times the position adjustment image is read exceeds 1 and is equal to or less than the upper limit, multiple pieces of positional deviation information are averaged according to the number of times the image is read. However, when the number of times the position adjustment image is read exceeds 1, multiple pieces of positional deviation information are not averaged according to the number of times the image is read, and a correction value may be calculated based on the latest positional deviation information.

[0105] In the above embodiment, when the number of times the position adjustment image is read exceeds the upper limit, the multiple pieces of positional deviation information are averaged according to the upper limit. However, the upper limit may be omitted. In this case, for example, the multiple pieces of positional deviation information may be averaged according to the number of times the position adjustment image is read, or the correction value may be calculated based on the latest positional deviation information without averaging the multiple pieces of positional deviation information.

[0106] In addition, in the above embodiments, the term "processor" refers to a processor in a broad sense, and includes general-purpose processors (e.g., CPU: Central Processing Unit, etc.) and dedicated processors (e.g., GPU: Graphics Processing Unit, ASIC: Application Specific Integrated Circuit, FPGA: Field Programmable Gate Array, programmable logic device, etc.).

[0107] Furthermore, the operations of the processor in the above embodiments may not only be performed by one processor, but may also be performed by multiple processors located at physically separate locations working together. The order of the operations of the processor is not limited to the order described in the above embodiments, and may be changed as appropriate. Some or all of the processors may be configured on a cloud. At least each process described in the above embodiments may be executed by a processor on a cloud.

[0108] In the above embodiment, the programs are installed in a ROM or storage device, but this is not limiting. The programs according to the above embodiment may be provided in a form recorded on a computer-readable storage medium. For example, the programs according to the above embodiment may be provided in a form recorded on an optical disc such as a CD (Compact Disc)-ROM or a DVD (Digital Versatile Disc)-ROM, or in a form recorded on a semiconductor memory such as a USB (Universal Serial Bus) memory or a memory card. The programs according to the above embodiment may also be acquired from an external device via a communication I / F.

[0109] In the above embodiment, the processing in the printing system 10 is described as being implemented by a software configuration using a computer by executing a program, but the present disclosure is not limited to this. For example, the processing in the printing system 10 may be implemented by a hardware configuration or a combination of a hardware configuration and a software configuration.

[0110] Furthermore, the configuration of the printing system 10 described in the above embodiment is merely an example, and it goes without saying that unnecessary parts may be deleted or new parts may be added within the scope of the present disclosure.

[0111] Furthermore, the processing flow in the printing system 10 described in the above embodiment is also an example, and it goes without saying that unnecessary steps may be deleted, new steps may be added, or the processing order may be rearranged within the scope of the present disclosure.

[0112] The following additional notes are provided regarding the above-described embodiments.

[0113] (((1))) a printing unit that prints a print job and prints a position adjustment image corresponding to each page of the print job; a reading unit that reads the position adjustment image printed by the printing unit; an adjustment unit that adjusts the print position of a page of the print job that is printed by the printing unit based on the position adjustment image read by the reading unit, A printing system characterized in that the adjustment unit adjusts the printing position of the smallest page for which the printing position can be adjusted, from the second page onwards of the print job, based on the position adjustment image of the first page of the print job. (((2))) The printing system described in (((1))) is characterized in that, each time the position adjustment image for the second page or subsequent pages of the print job is read, the adjustment unit adjusts the printing position of the page to be printed after adjusting the correction value based on the correction value adjusted using the read position adjustment image. (((3))) The printing system described in (((2))) is characterized in that the adjustment unit calculates positional deviation information of the position adjustment image for each page based on the position adjustment image, and adjusts the printing position of the page based on an averaged value obtained by averaging the calculated positional deviation information according to the number of times the position adjustment image is read. (((4))) The printing system described in (((3))) is characterized in that, when the number of readings exceeds a predetermined upper limit, the adjustment unit averages the positional deviation information according to the upper limit.

[0114] According to (((1))), in a printing system in which an adjustment unit adjusts the printing position of a page of a print job printed by a printing unit based on a position adjustment image read by a reading unit, it is possible to reduce the number of pages whose printing position is not adjusted. According to (((2))), the accuracy of adjusting the print position of a page can be improved compared to when the print position of all pages for which the print position can be adjusted is adjusted based on the position adjustment image of the first page of a print job. According to (((3))), the accuracy of adjusting the print position of a page can be improved compared to when the print position of all pages for which the print position can be adjusted is adjusted based on the position adjustment image of the first page of the print job. According to (((4))), the averaging process time can be reduced compared to when all calculated positional deviation information is averaged. [Explanation of symbols]

[0115] 10 Printing System 26 Printing Department 27 Adjustment part 31 Reading unit M Image for position adjustment

Claims

1. a printing unit that prints a print job and prints a position adjustment image corresponding to each page of the print job; a reading unit that reads the position adjustment image printed by the printing unit; an adjustment unit that adjusts the print position of a page of the print job printed by the printing unit based on the position adjustment image read by the reading unit, and adjusts the print position of the smallest page whose print position can be adjusted for the second and subsequent pages of the print job based on the position adjustment image of the first page of the print job; A printing system comprising:

2. The printing system described in claim 1, characterized in that the adjustment unit adjusts the printing position of the page to be printed after adjusting the correction value based on the correction value adjusted using the read position adjustment image each time the position adjustment image for the second page or later of the print job is read.

3. The printing system according to claim 2, characterized in that the adjustment unit calculates positional deviation information of the position adjustment image for each page based on the position adjustment image, and adjusts the printing position of the page based on an averaging value obtained by averaging the calculated positional deviation information according to the number of times the position adjustment image is read.

4. 4. The printing system according to claim 3, wherein when the number of readings exceeds a predetermined upper limit, the adjustment unit averages the positional deviation information in accordance with the upper limit.

Images