JP3790490B2 - Print quality control device and printing machine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
  The present invention relates to a quality control device for printed matter printed by a printing press.And printing pressAbout.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, a printing machine is provided with various quality control devices for managing the quality of produced printed matter. FIG. 7 shows a schematic configuration of a rotary printing press which is one of the printing presses equipped with such a quality control device.
In the printing section of the rotary printing press, two sets of printing units each including a plate cylinder 4 and a blanket cylinder 3 on which a plate 5 is mounted are arranged on the upper and lower sides of a continuous belt-like sheet 1. Each printing unit is provided with an ink supply unit composed of an ink source roller 6 and a plurality of ink keys 7 arranged in the axial direction of the ink source roller 6 (in FIG. 7, the ink supply unit of the upper printing unit). Ink is supplied to the plate cylinder 4 from a gap between the ink base roller 6 and each ink key 7 through a plurality of ink rollers (not shown). The ink supplied to the plate cylinder 4 adheres to the oleophilic region of the plate 5, and the ink attached to the plate 5 is transferred to the paper 1 through the blanket cylinder 3, so that the printed pattern 2 is continuous with the paper 1. Formed. Then, a sheet-like printed matter is obtained by cutting the paper 1 for each predetermined region including the printed pattern 2 by a folding machine (cutting unit) (not shown) provided downstream of the printing unit.
[0003]
As a quality control device for printed matter produced by such a rotary printing press, as shown in FIG. 7, a printing error discrimination processing device 20, a print defect inspection device 21, a cutting register control device 22 and a density control device 23 are known. It has been. The plate error determination processing device 20 is a device that determines whether or not the plate 5 is erroneously mounted, for example, whether the wrong plate 5 is mounted on the plate cylinder 4 or whether the plate 5 is upside down. . Conventionally, a bar code 5 a for distinguishing the plate 5 is written in the left or right margin of the plate 5. The plate error determination processing device 20 reads the barcode 5a with a barcode reader (or camera) 10 to determine whether the plate 5 is correctly attached. The determination result by the printing error determination processing device 20 is displayed on a dedicated display 30.
[0004]
The print defect inspection device 21 is a device that inspects a print defect in the printed pattern 2 printed on the paper 1. The printing defect referred to here refers to an abnormality that cannot be dealt with by normal density adjustment, such as the ink not being applied where the ink should be applied, or the pattern being crushed due to excessive ink. The print defect inspection apparatus 21 reads the print pattern 2 by the line sensor 11 and predetermines the obtained image data of the print pattern 2 and image data of a print pattern (printed material of a normal print pattern) captured in advance after starting printing. Compared for each area, an area where the density difference exceeds a predetermined threshold is determined to have a print defect. Note that the above-described area serving as a unit of comparison is determined in pixel units of the line sensor 11 or block units of a predetermined number of pixels. In addition, the inspection result by the print defect inspection apparatus 21 is displayed on a dedicated display 31.
[0005]
The cutting register control device 22 is a device that controls the cutting position of the sheet 1 in the folding machine. The folding machine cuts the sheet 2 at a speed synchronized with the traveling speed (printing speed) of the sheet 1, and the cutting timing (phase) of the fold 9 is obtained by cutting the sheet 1 by the printed pattern 2. It is set so as to come to a predetermined position of the leaf-like printed matter. However, during printing, the travel length of the paper 1 from the printing unit to the folding machine slightly changes due to a change in the amount of elongation of the paper 1 due to the tension variation, and the cutting position with respect to the reference position due to the change in the travel length. As a result, the position of the pattern in the printed material changes. Therefore, the cutting register control device 22 uses the CCD camera 12 to photograph a mark (cutting register mark) 2a printed in an area outside the printed picture area 2 of the paper 1, and uses the image data as a reference for the cutting register mark 2a. Measure the displacement relative to the position. This reference position is a virtual position where the cutting registration mark is supposed to be located if there is no deviation in the cutting registration. The cutting register control device 22 controls the compensator driving motor 9 according to the deviation of the measured cutting register mark 2a from the reference position, and corrects the position of the compensator roll 8 for guiding the paper 1 in the direction of the arrow in FIG. Thus, the running length of the sheet 1 from the printing unit to the folding machine is corrected, thereby correcting the misregistration of the cutting register. The control result by the cutting register control device 22 is displayed on a dedicated display 32.
[0006]
The density control device 23 is a device that controls the density of the printed picture 2. The density of the print pattern 2 is determined by the amount of ink supplied, and this ink supply amount depends on the gap between the ink base roller 6 and the ink key 7 (ink key opening) in the width direction of the print pattern 2 in units of the width of the ink key 7. It can be set arbitrarily. The density controller 23 reads the printed picture 2 by the density sensor 11 for density control, and compares the obtained density data of the printed picture 2 with the density data of the OK sheet read in advance in the width unit of the ink key 7. The opening degree of each ink key 7 is adjusted according to the density difference. Further, the control result by the density control device 23 is displayed on a dedicated display 33.
[0007]
[Problems to be solved by the invention]
The quality control devices 20, 21, 22, and 23 are indispensable for a rotary printing press when producing high-quality printed matter, but a plurality of input devices along the travel path of the paper 1. Since 10, 11, 12, and 13 are installed, a lot of installation space is required in the rotary printing press. Since each quality control device 20, 21, 22, 23 is independent and has a dedicated display 30, 31, 32, 33, respectively, these quality control devices 20, 21, A large amount of installation space is also required for installing the devices 22 and 23 and the display devices 30, 31, 32 and 33. Furthermore, since many devices are required, the cost is increased.
[0008]
  The present invention was devised in view of such a problem, and the quality management apparatus for a printed matter that enables the quality management of the printed matter to be saved in a space-saving and low-cost configuration with no waste.And printing pressThe purpose is to provide.
[0009]
[Means for Solving the Problems]
As a means for achieving the above object, the present invention uses a line sensor as a data input means for quality control, and performs various quality control processes using print pattern data read by the line sensor. Multiple functions related to print quality control have been integrated into a single device.
[0010]
  First, the present inventionPrinted matterThe quality control device is a line sensor that is arranged downstream of the printing unit of the printing press and reads a printed pattern printed on paper by the printing unit;A printed pattern data storage unit for storing printed pattern data read by the line sensor;Data acquisition means for acquiring sample pattern data as a sample of the printed pattern;A sample pattern data storage unit for storing the sample pattern data acquired by the data acquisition means;the abovePrinted picture data storage unit memorizedPrint pattern data and aboveSample picture data storage unit memorizedPrint defect detection means for detecting a print defect using the sample picture data and ink key opening control means for adjusting the opening of the ink key are provided. The print defect detection means compares the printed pattern data and the sample pattern data in pixel units of the line sensor or in block units of a predetermined number of pixels, and density difference (or difference in parameter value correlated with density) for each pixel or block. , And a print defect is detected by comparing the calculated difference with a predetermined threshold value. Ink key opening control meansPrinted picture data storage unit memorizedPrint pattern data andSample picture data storage unit memorizedCompare the sample pattern data with the width of the ink key in the print area in the width direction of the printed pattern and calculate the density difference (or the difference in the parameter value related to the density) for each ink key width. Adjust the ink key opening accordingly.Then, the predetermined threshold value used for printing defect detection is set to a value larger than the range of the difference generated in the density control by the ink key opening degree control means (claim 1).According to such a configuration, the image data read by the line sensor can be effectively used for detection of printing defects and adjustment of the ink key opening, and a printing defect detection function and an ink key opening adjustment function (density of printed matter). Control function) can be integrated into one device, and space saving and cost reduction can be realized.
[0011]
  abovePrinted matterQuality control equipmentPrinted picture data storage unit memorizedPrint pattern data andSample picture data storage unit memorizedWith sample pattern dataCompare multiple areasIt is possible to further include a printing error determination means for determining a printing error based on the overall match / mismatch.(Claim 2). As a result, the image data read by the line sensor can be used effectively for detecting printing defects and adjusting the ink key opening, as well as for discriminating plate errors. The adjustment function and the plate error determination function can be integrated into one apparatus, and further space saving and cost reduction can be realized.
[0013]
  The above printed matterWhen the quality control device of the machine has a printing error discriminating means, EditionThe discrimination process by the multiplying error discrimination means is preferably the following processing method. That is,Printed picture data storage unit memorizedPrint pattern data density histogram andSample picture data storage unit memorizedThe density histogram of the sample pattern data is compared in an area unit wider than the comparison unit in the print defect detection means, and the plate multiplication error is determined by the match / mismatch of the density histogram for each area.(Claim 3). In this way, the amount of comparison calculation can be reduced by performing processing in an area unit larger than the comparison unit in the print defect detection means, and the calculation load associated with the integration of the printing error discrimination function can be reduced. Can do.
[0014]
  Also, abovePrinted matterQuality control equipmentIn placeIn the case where the paper is a continuous belt-shaped paper and the printing press is a rotary printing press provided with a cutting unit that cuts the paper at a speed synchronized with the printing speed for each predetermined area including the print pattern, A sensor is disposed between the printing unit and the cutting unit, and a traveling length adjusting unit that adjusts the traveling length of the sheet from the printing unit to the cutting unit, and a cutting that corrects the traveling length by controlling the traveling length adjusting unit. And a register control means. The cutting register control means detects a deviation between the boundary position in the vertical direction of the printed picture and the cutting reference position from the printed picture data of the line sensor, and controls the travel length adjusting means in a direction to cancel the detected deviation.(Claim 4). As a result, the image data read by the line sensor can be effectively used for cutting register control, and the cutting register control function can be integrated into one device to achieve further space saving and cost reduction. Can do.
[0016]
  In addition,The above printed matterQuality control equipmentWherePlace with cutting register control meansTogetherThe reading of the printed pattern by the line sensor is preferably performed by the following method. That is, at least one of the top and bottom borders of the printed pattern is read with fine resolution, and the area on the printed pattern excluding the border is read with a coarser resolution than the vicinity of the boundary.(Claim 5). In order to control the cutting register, it is necessary to accurately grasp the boundary position of the printed pattern.In this way, only the area near the boundary is read with a fine resolution, and the other areas are read with a coarse resolution. And the calculation load associated with the integration of the cutting register control function can be reduced.
[0020]
  The abovePrint goodsIn the quality management apparatus, any of the following methods is preferable as a method of acquiring the sample pattern data by the data acquisition means. One is a method of acquiring image data for creating a plate used for producing a plate as sample pattern data from a plate making system that produces a plate used in a printing section.(Claim 6). The other is a method of acquiring sample picture data by reading a sample printed matter having a desired print quality with a line sensor.(Claim 7).
Moreover, the printing machine of this invention is the quality control apparatus of the printed matter of any one of Claims 1-7, the ink supply part which has an ink key by which the opening degree is adjusted by the said quality control apparatus, The said ink A printing unit that prints on the printed matter with the ink supplied from the supply unit, and a display that displays a control result in the quality control device are provided (claim 8).
[0021]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
FIG. 1 is a schematic configuration diagram showing an application example of a quality control device for printed matter according to an embodiment of the present invention to a rotary printing press. In FIG. 1, the same reference numerals are used for the same parts as in the prior art. Here, the description of the same part as the conventional one is omitted, and the main part of the present invention will be described mainly.
[0022]
As shown in FIG. 1, in the printed matter quality management apparatus according to this embodiment, a line sensor 50 and a display 60 are combined with an integrated quality management apparatus 40 that is a main body. The line sensor 50 is disposed downstream of the compensator roller 8 and upstream of a folding machine (cutting unit) (not shown), and reads the printed pattern 2 continuously printed on the paper 1 at a predetermined timing. In addition to the print pattern data that is the image data from the line sensor 50, the integrated quality control device 40 is supplied with sample pattern data (sample pattern data) from the plate making system 70 that is an upstream process. Yes. The sample pattern data is data for plate making, and the plate making system 70 creates the plate 5 based on the sample pattern data. On the other hand, from the integrated quality control device 40, various information related to quality control is transmitted to the display device 60, and a control signal (ink key opening correction command) for controlling the ink supply amount is transmitted to the ink key 7. A control signal (compensation correction command) for controlling the running length of the paper 1 is transmitted to the compensator drive motor 9.
[0023]
The functions of the integrated quality control device 40 are shown in detail in the functional block diagram of FIG. As shown in FIG. 2, the integrated quality management device 40 includes a printed pattern data storage unit 401, a sample pattern data storage unit 402, a histogram generation unit 403, a printing error determination unit 404, a boundary position deviation detection unit 405, and cutting register control. 406, an ink key width-specific density comparison unit 407, an ink key opening degree control unit 408, a pixel-specific density comparison unit 409, and a print defect detection unit 410. The integrated quality management apparatus 40 can also be realized by using a general computer. In this case, each unit 401 described above is obtained by the cooperation of computer components such as a CPU, RAM, and ROM and a program. ˜410 are virtually configured.
[0024]
The printed pattern data storage unit 401 is a part that stores printed pattern data read by the line sensor 50. Print pattern data is transmitted from the line sensor 50 to the print pattern data storage unit 401 at a predetermined cycle, and the print pattern data storage unit 401 temporarily stores an amount of print pattern data corresponding to at least one print pattern 2. It is like that. The data reading cycle of the line sensor 50 is schematically shown in the plan view of FIG. In FIG. 3, the period between the broken lines crossing the paper 1 and the broken line indicates the data reading cycle, and it can be seen that there are a short region S1 and a long region S2. The period of data reading is related to the resolution of the printed picture data. In the area S1, a fine resolution of L1 is obtained in the vertical direction of the printed picture 2, whereas in the area S2, L2 is obtained in the vertical direction of the printed picture 2 that is coarser than the area S1. Can be obtained. The area S1 corresponds to the vicinity of the border in the vertical direction of the printed picture 2 and the non-printing area between the printed pictures 2 and 2, and the area S2 corresponds to the area on the printed picture 2 excluding the vicinity of the boundary.
[0025]
The sample picture data storage unit 402 is a part that stores the sample picture data acquired from the plate making system 70. Input of the sample pattern data from the plate making system 70 to the sample pattern data storage unit 402 may be online input via a communication network or offline input via a recording medium such as a magnetic disk. The line sensor 50 generally measures spectral values. On the other hand, the data format of the sample pattern data includes halftone dot area ratios, densities, and color coordinate values (L, a, and K) of each color (C, M, Y, K). b) is used. In the integrated quality control device 40, a table (not shown) for associating these spectral values, halftone dot area ratios, densities and color coordinate values with each other in advance is facilitated. Data, here converted into density and stored in the respective storage units 401 and 402.
[0026]
The histogram creating unit 403 and the printing error discriminating unit 404 are parts corresponding to printing error discriminating means according to the present invention. The histogram creation unit 403 creates a density histogram of the printed pattern data stored in the printed pattern data storage unit 401 for each predetermined area, and the sample pattern data stored in the sample pattern data storage unit 402 for each area. A density histogram is also created.
[0027]
The printing error discriminating unit 404 has a function of discriminating a printing error of the plate 5 based on the coincidence / non-coincidence between the density histogram of the printed pattern data created by the histogram creating unit 403 and the density histogram of the sample pattern data. . In FIG. 4, when the density histogram of the sample pattern data is represented by a solid line, if the correct plate 5 is mounted in the correct direction on the plate cylinder 4, the density histogram of the printed pattern data is also represented by a solid line. Alternatively, it is represented by a density histogram having substantially the same shape. However, if the wrong version is installed, or if the correct version is installed in the wrong direction, the density histogram of the printed picture data will show the density of the sample picture data as shown by the two-dot chain line in FIG. The shape is completely different from the histogram. The printing error discriminating unit 404 compares such density histograms for a plurality of areas, and discriminates the printing error of the printing plate 5 based on the overall match / mismatch. The area for creating the density histogram may be an area corresponding to one reading cycle in FIG. 3 (an area sandwiched between a broken line and a broken line) or a wider area over a plurality of periods. However, it is preferable that the areas are subdivided in order to more accurately determine the application error of the plate 5, and at least two areas are provided in the vertical direction. An error in the plate itself can also be determined by comparing the density histograms of the entire pattern data, but an error in the mounting orientation of the top and bottom cannot be determined by comparing the entire density histogram, and at least two areas must be compared in the vertical direction. Because it becomes. The determination result of the printing error determination unit 404 is output to the display device 60, and a warning is displayed on the display device 60 when there is a printing error.
[0028]
The boundary position deviation detection unit 405 and the cutting register control unit 406 are parts corresponding to the cutting register control unit according to the present invention. The boundary position deviation detection unit 405 detects a deviation of the border position in the vertical direction of the printed pattern 2 from the cutting reference position from the printed pattern data stored in the printed pattern data storage unit 401. As shown in FIG. 3, the printed picture 2 is read by being subdivided into a plurality of temporally continuous frames by the line sensor 50, and the plurality of subdivided frames are printed as print picture data as a whole. It is stored in the picture data storage unit 401. The boundary position deviation detection unit 405 detects, by image analysis, a frame including the boundary in the vertical direction of the print pattern 2 from a plurality of frames constituting the print pattern data stored in the print pattern data storage unit 401. A shift of the frame from the reference frame is detected. The reference frame is a frame including the boundary of the printed pattern 2 if there is no deviation in the cutting register, and corresponds to the cutting reference position.
[0029]
The cutting register control unit 406 outputs a control signal (compensation correction command) to the compensator drive motor 9 according to the amount of deviation of the boundary position of the printing unit 2 detected by the boundary position deviation detection unit 405. The compensator drive motor 9 is actuated by the control signal, and the compensator roll 8 moves in the direction of the arrow in FIG. 1, so that the running length of the paper 1 from the printing unit to the folding machine changes. The compensator roll 8 and the compensator drive motor 9 correspond to the travel length adjusting means according to the present invention. The cutting register control unit 406 moves the compensator driving motor 9 in such a direction that the change in the running length of the sheet 1 due to the movement of the compensator roll 8 absorbs the deviation of the boundary position of the printed pattern 2 from the cutting reference position, that is, the deviation of the cutting register. Operate. In the present embodiment, as shown in FIG. 3, in the region S1 in the vicinity of the boundary of the printed pattern 2, the data reading cycle of the line sensor 50 is set to be short, so that the temporal detection error of the boundary position of the printed pattern 2 is reduced. The amount of misregistration of the trimming register can be obtained accurately. In other words, by shortening the data reading cycle only for the part necessary for detecting the boundary position, the total calculation amount is reduced and the calculation load is reduced. The control result of the cutting register control unit 406 is output to the display device 60, and the position control status of the compensator roll 8 is displayed on the display device 60.
[0030]
The ink key width-specific density comparison unit 407 and the ink key opening degree control unit 408 are portions corresponding to the ink key opening degree control means according to the present invention. As shown in FIG. 5, the density comparison unit 407 for each ink key width uses the print pattern data stored in the print pattern data storage unit 401 and the sample pattern data stored in the sample pattern data storage unit 402 of the print pattern 2. In the width direction, comparison is made in units of area A1 of the width W of the ink key 7, and the density difference is calculated for each ink key width area A1.
[0031]
The ink key opening degree control unit 408 outputs a control signal (ink key opening degree correction command) to the corresponding ink key 7 according to the density difference of each region A1 calculated by the density comparison unit 407 classified by ink key width. When the tip of the ink key 7 is swung vertically by the control signal, the gap amount (ink key opening degree) between the ink base roller 6 and the ink key 7 is changed, and the ink supply amount is changed. The ink key opening degree control unit 408 operates the ink key 7 in such a direction that the change in the ink supply amount accompanying the change in the ink key opening degree eliminates the density difference between the printed pattern 2 and the sample pattern. The control result of the ink key opening degree control unit 408 is output to the display device 60, and the current ink key opening degree of each ink key 7 is displayed on the display device 60.
[0032]
The pixel-by-pixel density comparison unit 409 and the print defect detection unit 410 are portions corresponding to the print defect detection unit according to the present invention. As shown in FIG. 6, the pixel-by-pixel density comparison unit 409 prints image data stored in the print image data storage unit 401 and sample image data stored in the sample image data storage unit 402 for each pixel P of the line sensor 50. And the density difference is calculated for each pixel P. The density difference may be compared not in units of pixels P but in units of blocks including a plurality of pixels P. The size of the block is arbitrary, but it is preferable to set the block small in order to detect printing defects with high accuracy.
[0033]
The print defect detection unit 410 compares the density difference calculated by the pixel-by-pixel density comparison unit 409 with a predetermined threshold value. Here, in order to detect defects in which the print density is abnormal, such as when the ink is not applied where it should be applied, or when the pattern is crushed due to excessive ink, the above threshold is It is set to a value that is much larger than the range of density differences that normally occur in density control by the density comparison unit 407 and ink key opening degree control unit 408. The control result of the print defect detection unit 410 is output to the display device 60. If there is a print defect, a warning is displayed on the display device 60.
[0034]
As described above, the quality control apparatus according to the present embodiment uses the printed pattern data read by the line sensor 50 to determine plate error, controls cutting registration, controls ink key opening, and further prints. Defects can be detected. Therefore, it is not necessary to secure an installation space for installing a plurality of cameras on the travel route of the paper 1 as in the prior art. Further, since all the functions (determination error determination, cutting register control, ink key opening control, and print defect detection) are integrated in one integrated quality control apparatus 40, the integrated quality control apparatus 40 and the display 60 are integrated. The quality control as before can be performed only by providing one each. Therefore, the installation space for these equipments can be reduced and the cost can be reduced.
[0035]
Further, in the quality control apparatus of the present embodiment, it is not necessary to provide a barcode on the plate as in the prior art because the plate application error is determined from the printed picture data. Similarly, since the misregistration of the cutting register is detected from the printed pattern data, it is not necessary to print the cutting register mark separately from the printed pattern as in the prior art. Accordingly, it is possible to eliminate the need for extra operations such as bar code management and excision of cut registration marks after printing.
[0036]
Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the spirit of the present invention.
The integrated quality management device 40 does not necessarily include all the functions described above, and it is of course possible to provide only necessary functions according to the required quality control items. For example, when the printing machine is a sheet-fed printing machine, the cutting register control is unnecessary, and therefore, at least the boundary position deviation detection unit 405 and the cutting unit among the units 101 to 410 of the integrated quality management apparatus 40 illustrated in FIG. The register control unit 406 can be omitted. In addition, when the printing press is not an ink key type ink supply device but an ink supply device of another type, the density comparison unit 407 for each ink key width and the ink key opening control unit 408 can be omitted. .
[0037]
Note that the resolution (number of pixels) of the line sensor 50 may be selected according to the required function. That is, when printing defect detection is performed as in the above-described embodiment, it is preferable to increase the resolution by increasing the number of pixels. However, if printing defect detection is not performed, the next highest resolution is achieved. In this case, the number of pixels required for the ink key opening control may be selected.
[0038]
In the above-described embodiment, the image data for creating a plate is acquired as sample pattern data from the plate making system. However, the line sensor 50 reads a sample printed matter (so-called OK sheet) having a desired print quality. It is also possible to acquire sample pattern data. In this case, since the sample pattern data also has the same spectral value as the printed pattern data, the ink key opening is controlled from the difference by directly comparing the two without performing data conversion using a table as in the embodiment. It is also possible to detect printing defects.
[Brief description of the drawings]
FIG. 1 is a schematic diagram illustrating an overall configuration when a print quality management apparatus according to an embodiment of the present invention is applied to a rotary printing press.
FIG. 2 is a functional block diagram illustrating a configuration of the print quality management apparatus in FIG. 1;
FIG. 3 is a plan view illustrating an example of setting resolution of a line sensor according to the print quality management apparatus of FIG. 1;
4 is an explanatory diagram for explaining a printing error determination method according to the print quality management apparatus of FIG. 1; FIG.
FIG. 5 is an explanatory diagram for explaining a method of controlling the ink key opening according to the print quality management apparatus of FIG. 1;
6 is an explanatory diagram for explaining a cutting register control method according to the print quality management apparatus of FIG. 1; FIG.
FIG. 7 is a schematic diagram showing the overall configuration of a conventional print quality management apparatus applied to a rotary printing press.
[Explanation of symbols]
1 paper
2 Print pattern
3 Blanket body
4 Plate cylinder
5th edition
6 Ink base roller
7 Ink key
8 Compensator roller
9 Compensator drive motor
40 Integrated quality control device
50 line sensor
60 indicator
70 Plate making system
401 Print pattern data storage unit
402 Sample picture data storage unit
403 Histogram creation part
404 Printing error discriminator
405 Boundary position deviation detector
406 Cutting register control unit
407 Density comparison section by ink key width
408 Ink key opening controller
409 Density comparison unit by pixel
410 Print defect detector

Claims (8)

A line sensor that is arranged downstream of the printing unit of the printing press and reads a printed pattern printed on paper by the printing unit;
A printed pattern data storage unit for storing printed pattern data read by the line sensor;
Data acquisition means for acquiring sample pattern data as a sample of the printed pattern;
A sample pattern data storage unit for storing the sample pattern data acquired by the data acquisition means;
The printed pattern data stored in the printed pattern data storage unit and the sample pattern data stored in the sample pattern data storage unit are compared in units of pixels of the line sensor or in units of blocks of a predetermined number of pixels. A print defect detection means for calculating a density difference or a difference in parameter values correlated with the density for each time, and detecting a print defect by comparing the calculated difference with a predetermined threshold;
The print pattern data stored in the print pattern data storage unit and the sample pattern data stored in the sample pattern data storage unit are compared in the width direction of the print pattern for each ink key width in the width direction of the print pattern. An ink key opening degree control means for calculating a difference in density or a parameter value correlated with the density, and adjusting the opening degree of the ink key according to the magnitude of the calculated difference ,
The quality control of the printed matter, wherein the predetermined threshold value is set to a value larger than the above-described density difference used in density control by the ink key opening degree control means or a parameter value difference range correlated with density. apparatus. The printed pattern data stored in the printed pattern data storage unit and the sample pattern data stored in the sample pattern data storage unit are compared in a plurality of areas, and an error of the plate is determined by the overall match / mismatch. 2. A quality control apparatus for printed matter according to claim 1, further comprising printing error discriminating means. The printing error determining means is a unit for comparing the density histogram of the printed picture data stored in the printed picture data storage section and the density histogram of the sample picture data stored in the sample picture data storage section in the print defect detecting means. compared with a wide area units than, characterized in that to determine the multiplying error of the plate by the match / mismatch of the density histogram for each of the areas, the quality control apparatus of a printed material according to claim 2 Symbol placement. In the case where the paper is a continuous belt-like paper, and the printing press is a rotary printing machine provided with a cutting unit that cuts the paper at a speed synchronized with the printing speed for each predetermined region including the printed pattern.
The line sensor is disposed between the printing unit and the cutting unit,
A running length adjusting means for adjusting the running length of the paper from the printing unit to the cutting unit;
A cutting register control for detecting a deviation between the top and bottom boundary position of the printed picture and the cutting reference position from the printed picture data, and correcting the running length by controlling the running length adjusting means in a direction to cancel the detected deviation. and further comprising a means, quality control apparatus of a printed material according to any one of claims 1-3. The line sensor is characterized in that at least one of the top and bottom boundaries of the printed pattern is read with fine resolution, and the area on the printed pattern excluding the vicinity of the boundary is read with coarser resolution than the vicinity of the boundary. The quality control apparatus for printed matter according to claim 4 . Upper Symbol data acquisition means, from the plate-making system of manufacturing a plate used in the printing unit, characterized by the Turkey to obtain a sample picture of the data used for manufacturing the plate, one of the claims 1 to 5 A quality control device for printed matter according to claim 1 . Said data acquisition means and acquires the sample picture data sample printed material with desired print quality by reading by the line sensor, the printed matter according to any one of claims 1 to 6 Quality control equipment. A quality control device for printed matter according to any one of claims 1 to 7,
  An ink supply unit having an ink key whose opening is adjusted by the quality control device;
  A printing unit that prints on the printed matter with the ink supplied from the ink supply unit;
  A display for displaying a control result in the quality control device;
A printing machine comprising:

Images