JP3564388B2 - DOUBLE DETECTION METHOD, DOUBLE DETECTION MARK, AND DOUBLE DETECTION DEVICE - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention detects a phenomenon called dubble in the printing world, in which a plurality of units having a printing plate cylinder perform multicolor printing and the color transferred to the second and subsequent plate cylinders is shifted and retransferred. The present invention relates to a doubling detection method, a doubling detection mark, and a doubling measurement device.
[0002]
[Prior art]
As shown in FIG. 7, a general printing press includes a paper feed unit 1, printing devices 2a, 2b, 2c, 2d,... 2n provided corresponding to colors to be printed, a paper discharge unit 3, and the like. Further, each printing device 2 has a plate cylinder 4, a blanket cylinder 5, an impression cylinder 6, an intermediate cylinder 7, etc., around which a printing plate is wound. Then, a corresponding color ink is supplied from a not-shown ink supply device to the character image portion of the printing plate wound around the plate cylinder 4 of each printing device 2, and the ink is transferred to the blanket cylinder 5. Thereafter, the printing paper 8 supplied from the paper feeding unit 1 is re-transferred by the impression cylinder 5 to perform printing.
[0003]
However, as shown in FIG. 8, the halftone dot of the character image printed at the point P1 of the printing paper 8 at the point B1 of the blanket cylinder 5a is the pressure of the impression cylinder 6b when the next image is printed by the blanket cylinder 5b. Is re-transferred from the printing paper 8 side to the point B1 'of the blanket cylinder 5b. There is no problem if the halftone dot of the character image printed on the next printing paper 8 at the point P1 coincides with the position of the halftone dot B1 'retransferred to the impression cylinder 6b. When the halftone dot B1 'is printed at the point P2, a thin halftone dot of the same color as the point P1 is printed at the point P2 as shown in FIG. This is what is called double. At this time, the halftone dot of the character image printed on the P1 point of the second printing paper 8 is retransferred to the B2 point of the blanket cylinder 5b, which also causes double.
[0004]
When this double occurs, the direction of the double changes regularly for each sheet as described above, and the ink density differs for each sheet or the ink density differs between right and left. Phenomena such as high. The cause of the double is caused by a decrease in biting accuracy due to clogging of a nail holding the printing paper 8 in the impression cylinder 6 and a decrease in accuracy due to wear of gears. However, the direction and amount of the double are not accurately grasped. And the exact cause cannot be determined.
[0005]
[Problems to be solved by the invention]
However, in the related art, the dubbing has been performed by a method in which a skilled person observes a halftone dot with a loupe to determine the amount and direction, and predicts the cause to cope with it. Therefore, a skilled person is always required, and it takes time to identify and deal with the cause, and it is necessary to stop the printing press for a long time, which may cause a great deal of damage.
[0006]
In addition, this color doubling cannot be accurately reproduced unless it is detected in the order of 20 to 30 μm. In addition, in the case of a decrease in biting accuracy due to clogging of a nail holding a printing paper, local occurrence may occur. Thus, some parts appear large on the same printing paper, and some parts appear small. Therefore, having to deal with such a situation by one skilled person alone takes a long time, and in some cases, causes an erroneous grasp of the cause, which in some cases increases the damage.
[0007]
Therefore, an object of the present invention is to provide a double detection method and a double detection device which can quickly and automatically measure the amount and direction of the double.
[0008]
[Means for Solving the Problems]
Claim 1 is a method invention,
In a printing machine that performs multicolor printing with a plurality of units having a printing plate cylinder, the printing color of the preceding unit transferred to the plate cylinder of the succeeding unit in the succeeding unit is shifted and retransferred to printing paper. A method for detecting doubling, wherein
A small circle center mark and a ring-shaped mark concentrically surrounding the center mark form a double detection mark, and the major and minor diameters of the printed double detection mark are measured, and the difference between the two is determined. At one time, the difference is defined as a double fog amount.
[0009]
By forming the doubling detection mark in a ring shape in this manner, even if the mark becomes thick due to ink crushing or bleeding at the time of printing, this thickening appears evenly over the entire 360-degree circumference of the mark. By measuring the major axis and minor axis of this mark and detecting the difference between them, the presence / absence and amount of double and the direction thereof can be easily and accurately detected, and prompt measures can be taken.
[0010]
The doubling direction is defined as "the direction of the major axis is the doubling direction".
[0011]
As described above, according to the first and second aspects of the present invention, the amount and direction of the doubling can be measured quickly and automatically.
The measurement of the major axis and the minor axis is performed as described in claims 3 and 4.
The short diameter and the long diameter are measured as distances from the center position coordinates of the small circular center mark.
And, the doubling detection mark is divided into a plurality at a fixed angle around the center position coordinates of the center mark, and within each of the divided angles, the minor axis and the major axis are measured from the center position coordinates, and the average value is calculated. The maximum value of the average value is defined as the major axis, and the minimum value is defined as the minor axis.
[0013]
By measuring the major axis and the minor axis from the coordinates of the center position of the small circular center mark, it is possible to easily and accurately measure the major axis and the minor axis.
[0014]
In addition, the major axis and the minor axis are, as described in claims 5 , 6, and 7 ,
The short diameter and the long diameter are measured at the outer circumference or the inner circumference of the ring-shaped mark.
Further, the minor axis and the major axis are measured at the outer periphery of the small circular center mark.
And, a plurality of doubling detection marks are arranged to form a group with a small circular center mark and a ring-shaped mark concentrically surrounding the center mark, and the major axis and minor axis of each doubling detection mark are measured. In addition, the average value of a plurality of doubling amounts determined from the difference between the two is set as the doubling amount.
[0015]
By measuring the minor axis and major axis at the outer and inner peripheries of the ring-shaped mark and the outer perimeter of the small circular center mark and determining their respective values, or determining the average value, accurate values can be measured. .
[0016]
The double detection mark used in the method described above is, as described in claims 8 and 9 ,
A small circle center mark and a ring mark surrounding the center mark concentrically form a double detection mark, a plurality of the same color double detection marks are arranged to form a group, and the group is printed in multiple colors. Is provided for each printing color used .
A small circle center mark and a ring mark surrounding the center mark concentrically form a double mark detection mark, and the double mark detection mark formed for each printing color used for the multicolor printing is used. It is characterized in that it is arranged in a predetermined frame to be a multicolor double detection mark, and a group is formed by arranging a plurality of multicolor double detection marks .
[0017]
By forming the double detection mark in a group as described above, if only a single mark is detected, it may be impossible to detect the double mark even if the double mark actually occurs, but a plurality of marks may be detected. By measuring, you will not miss it.
[0018]
Then, the doubly measuring device for detecting the doubly detecting mark and measuring the amount and the direction is as described in claim 10 ,
A storage unit for storing position coordinates of a double detection mark formed by the small circular center mark and a ring-shaped mark concentrically surrounding the center mark; and a two-dimensional moving means for moving the two-dimensional area sensor by two-dimensional moving means. After being moved to the coordinate position of the double detection mark stored in the storage unit, the two-dimensional area sensor detects the double detection mark printed on the double detection mark and measures the major axis and the minor axis of the double detection mark to measure both. When there is a difference, a control unit that sets the difference to a double amount is provided .
[0019]
By configuring the measuring device in this way, the amount of doubling and the direction can be automatically measured with high accuracy.
[0020]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, embodiments of the present invention will be illustratively described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention to them unless otherwise specified, and are merely mere descriptions. This is just an example.
[0021]
FIG. 1 shows an example of a doubling detection mark according to the present invention. In the present invention, a small circular center mark 30 placed at the center and a ring-shaped mark 31 surrounding the center mark as shown in FIG. A detection mark is formed and prepared for each color used in printing. The dub detection mark is formed in a ring shape in this way because, in general, thickening occurs due to crushing or bleeding of ink during printing, but the thickening of a circle occurs evenly over 360 degrees. The size of the double detection mark is formed, for example, such that the diameter of the small circular center mark is about 20 μm to 35 μm, the diameter of the outer circle of the ring mark is about 400 μm, and the diameter of the inner circle is about 200 μm. However, these numerical values are approximate values, and are not limited thereto.
[0022]
When the double detection mark formed in this way is printed and double generation occurs, the state shown in FIG. 2 is obtained. That is, in FIG. 2, reference numerals 30 and 31 are the double detection marks shown in FIG. 1, and reference numerals 40 and 41 are the double marks generated by double.
[0023]
When detecting double, the outer circumference, inner circumference, and center mark of the double detection mark printed on the printed matter are measured over the entire 360 degrees, and it is assumed that double has occurred when there is a difference in diameter. In this case, the amount of doubling is, for example, the difference between the outer diameter of the ring-shaped mark or the shortest diameter (shorter diameter) 42 and the longest diameter (longer diameter) 43 of the center mark. Become. When the major axis and the minor axis are measured on the inner circumference of the ring-shaped mark, the difference between the minor axis and the major axis is still the amount of doubling, but the direction of the minor axis is the doubling direction.
[0024]
In the above description, first, the diameter of the double detection mark is measured over the entire 360 degrees, and then the major axis passing through the center mark 30 is set as the double direction. However, the center mark 30 is detected first. The diameter of the ring mark may be measured with the center mark as the center, and the longer diameter may be set to the double direction.
[0025]
Further, the difference between the minor axis 42 and the major axis 43 is defined as the amount of doubling as described above. As described above, thickening occurs due to crushing or bleeding of the ink, and the difference between the thick measured value and a previously known diameter of 400 μ is determined. In such a case, an accurate value cannot be obtained. However, if this is a method of taking the difference between the minor axis and the major axis, in the case of a circle, the thickness is evenly generated over the entire circumference of 360 degrees, and the amount of double bleeding can be accurately measured.
[0026]
In addition, even if the double detection mark is formed in this way, if it is used alone, in some cases, the difference between the short diameter and the long diameter cannot be detected due to blurring or the like despite the occurrence of double, In addition, even if there is a difference, a correct amount of double filing cannot be measured.
[0027]
Therefore, in the present invention, as shown in FIG. 3, the double detection mark shown in FIG. 1 is arranged in a predetermined frame 50 for each color to form a multicolor double detection mark. A plurality of marks are arranged to form a multicolor double detection mark group. Separately from this, a plurality of the double-mark detection marks shown in FIG. 1 are arranged as shown in FIG. 4 to form a single-color double-mark detection mark group, all of which are the same color, and this group is provided for each color used in printing.
[0028]
Then, as shown in FIG. 5, the multicolor double detection mark group 61, the single color double detection mark group 62, 63, 64, 65, and the position detection provided so that these double detection mark groups can be automatically detected. The use marks 66 are arranged at regular intervals, and by measuring these two types of mark groups, the average of the amount of doubling can be obtained, so that the above-described blur and error can be dealt with. The distance from the position detection mark 66 to the multicolor double detection mark group 61, the single color double detection mark group 62, 63, 64, 65, and the distance between the marks in each group are determined in advance by the double measurement apparatus. It is stored in the storage unit.
[0029]
Note that the example in FIG. 3 shows a case where the colors constituting the multicolor double detection mark are four colors, and black 51, cyan 52, magenta 53, and yellow 54 are arranged in the frame 50. The numbers may be similarly arranged. Also, the case where the number of double detection marks constituting the group is 8 × 8 is shown, but it is obvious that the number is not limited to this number.
[0030]
The above is the details of the double detection mark according to the present invention. The double detection device of the present invention will be described below with reference to FIG.
[0031]
The lower part of FIG. 6 is a schematic perspective view of an apparatus showing the form of the double burring measuring apparatus of the present invention, and the upper part is a control block diagram thereof. In the drawing, reference numeral 70 denotes a doubling measuring device, 71 denotes a table on which a printed matter is placed, 72 denotes a printed matter, 73 denotes a group of marks for detecting doubling printed on the printed matter as described in FIG. And 75, a two-dimensional area sensor constituted by a CCD area sensor or the like for imaging a two-dimensional area, which has a high-magnification optical system and can image an area of about 1 × 1 mm on a printed matter. Reference numeral 76 denotes a measuring device such as a laser displacement meter for measuring an interval (height) between the two-dimensional area sensor 75 and the printed matter 72, and the laser light of the laser displacement meter is also used as a laser pointer indicating a measurement position.
[0032]
Reference numeral 77 denotes a Z-axis stage which has a step motor or a ball screw and moves in the Z-axis direction in order to adjust an interval (height) between a measurement device such as a two-dimensional area sensor 75 or a laser displacement meter 76 and the printed matter 72. A moving table for moving the measuring device and the Z-axis stage 77 together, a motor 79 for driving a ball screw for moving the moving table 78 in the X-axis direction, and a high-precision position detecting device such as a rotary encoder for performing position detection. X-axis driving device, 80 is a Y-axis driving device having a motor for driving a ball screw or the like that moves in the Y-axis direction, and a Y-axis driving device having a high-precision position detecting device such as a rotary encoder for detecting the position. 81 is an XYZ-axis motor. The motor drive unit 82 drives the X-axis drive device 79 and the rotary encoder included in the Y-axis drive device 80. Is a signal from the laser displacement meter 76, and the distance (height) between the two-dimensional area sensor 75 and the printed matter 72 is a signal from the laser displacement meter 76. The height detection unit 84 calculates the coordinates of the position detection marks 66 shown in FIG. 5 and the multicolor double detection mark groups 61 and the single color double detection mark groups 62 and 63 from the position detection marks 66. A coordinate storage unit that stores distances to 64 and 65 and a distance between the double detection marks in each group, 85 is a control unit, and 86 stores the shape of the double detection mark shown in FIG. A pattern storage unit 87 is a pattern matcher that performs matching between the image pattern detected by the two-dimensional area sensor 75 and the shape of the double detection mark stored in the pattern storage unit 86. Grayed portion, 88 is a moving amount and direction instructing section that instructs a moving direction and the moving amount of the moving table 78 which holds the measuring device, the like arrow keys or a joystick. Reference numeral 89 denotes an input device such as a keyboard, and reference numeral 90 denotes a display device that displays a double detection mark, a double amount, and a double direction.
[0033]
In order to measure the amount of doubling with the doubling measuring device configured as described above, first, the printed matter 72 is positioned and placed on the table 71 of the doubling measuring device 70 with the positioning pins 74 of the printing paper. Then, the movement amount / direction instructing section 88 instructs the movement of the movement table 78 so that the laser light of the laser displacement meter 76 indicates the position of the position detection mark 66 in FIG. Then, the control unit 85 causes the motor driving unit 81 to drive the X-axis driving device 79 and the Y-axis driving device 80 to move the moving table 78 to the designated position.
[0034]
When the laser beam from the laser displacement meter 76 indicates the position of the position detection mark 66 in FIG. 5, as described above, the position detection mark 66, the multicolor double detection mark group 61, and the single color double detection mark group Since the distances from 62, 63, 64, and 65 and the distance from the position of the laser beam of the laser displacement meter 76 to the two-dimensional area sensor 75 are stored in the coordinate storage unit 84 in advance, the control unit 85 This value is read from 84 and an instruction is sent to the motor drive unit 81 to move the movement table 78 to a position where the two-dimensional area sensor 75 can image the first mark in the multicolor double detection mark group 61 in FIG. Let it.
[0035]
Then, the distance (height) to the printed matter 72 is measured by the laser displacement meter 76, and the result is sent to the height detecting unit 83 to detect the height from the printed matter 72 to the two-dimensional area sensor 75. The result is sent to the control unit 85, and if the height is inappropriate for the doubling measurement, a signal is further sent to the motor driving unit 81, and the step motor of the Z-axis stage 77 is driven, so that the optimum doubling measurement is performed. Adjusted to height.
[0036]
When the preparation for the double doubling measurement is completed, the control unit 85 causes the two-dimensional area sensor 75 to capture the first double doubling detection mark, sends the image to the pattern matching unit 87, and causes the display device 90 to display the image through the control unit 85. Then, the pattern matching section 87 performs matching between the doubling detection mark stored in the pattern storage section 86 and the doubling detection mark on the printed matter 72 that has just been captured. Then, when the position of the double detection mark is detected, the control unit 85 measures the diameter of the mark over the entire circumference of 360 degrees.
[0037]
If the diameter of the double detection mark is substantially the same over the entire circumference of 360 degrees, it is determined that there is no double and the next mark is measured. In the same manner, all the marks of the multi-color double detection mark group indicated by 61 in FIG. 5 are measured, and if no double is detected, the single-color double detection marks 62, 63, 64, and 65 are sequentially measured. When no double is detected in all the marks, it is determined that no double has occurred.
[0038]
However, as a result of measuring the diameter over the entire 360 degrees, if there is a difference between the minor axis 42 and the major axis 43 as shown in FIG. 2, the control unit 85 determines that the doubling has occurred and calculates the difference between the two. Then, this is displayed on the display device 90 as the amount of doubling, and the direction of the major axis 43 passing through the center mark 30 is set as the doubling direction, and this is also displayed at the same time.
[0039]
Then, as described above, the multi-color double detection mark group and the single-color double detection mark group are sequentially measured in the same manner, and the average of the measurement results is displayed for the color in which the double detection is detected. . In addition, as described above, since the doubling may appear locally on the printing paper, the doubling detection mark group shown in FIG. 5 is printed at a plurality of positions, so that the doubling appears at any position. To
[0040]
With the configuration of the doubling measuring device as described above, the doubling in multicolor printing can be easily, accurately, and quickly measured.
[0041]
In the above description, when measuring the amount of double filing, the diameter is simply measured over the entire circumference of 360 degrees. However, as described above, three types of methods are conceivable. First, a method for measuring the diameter of the outer circle of the ring mark 31 in FIG. 1, a method for measuring the diameter of the inner circle, and a method for measuring the diameter of the center mark 30 are shown in FIG. In any of these three methods, the difference between the major axis and the minor axis is the amount of double. However, when measuring the outer circle of the ring mark 31 and the diameter of the center mark 30, the direction of the major axis is the double direction. When the diameter of the inner circle of the ring-shaped mark 31 is measured, the direction of the minor axis is the double direction.
[0042]
In this case, the major axis and the minor axis measured by each method may be independently measured results by the respective methods, or an average of the results measured by the three kinds of methods may be obtained and used as the measurement result. Is also good.
[0043]
Furthermore, there are three types of methods for measuring each diameter. First, the center position coordinates of the center mark 30 are detected and the diameter passing therethrough is measured. Also, the distance from the center position coordinates to each circle is calculated. That is, a method of measuring the radius, and dividing the doubling detection mark into a plurality at a fixed angle around the center position coordinates of the center mark 30, and within each of the divided angles, the minor axis and the major axis are calculated from the center position coordinates. In this method, an average value is calculated by a plurality of measurements, the maximum value of the average value is defined as the major axis, and the minimum value is defined as the minor axis.
[0044]
Further, as a method of obtaining the center of the center mark, the center position of the center mark 30 is also stored in advance in the pattern storage unit 86, and the two-dimensional area sensor 75 takes an image of the double detection mark and stores it in the pattern storage unit 86. When matching with the present double detection mark, the center position coordinates are also calculated. With this configuration, the measurement of the major axis and the minor axis described above can be easily performed from the coordinates of the center position.
[0045]
Similarly, if the matching of the center mark 30 is achieved, the contraction of the image of the center mark 30 may be repeated, and the last remaining point may be used as the center position coordinate.
[0046]
In the above description, the position of the position detection mark 66 is instructed by the movement amount / direction instructing unit 88. However, this is configured so that a numerical value is input in advance from the input device 89 and the measurement is automatically performed. May be. In addition, since the measurement of the doubling is performed several times during printing, the position may be stored in the coordinate storage unit 84 and the two-dimensional area sensor 75 may be configured to automatically search for the position.
[0047]
【The invention's effect】
As described above, according to the present invention, by forming the doubling detection mark in a ring shape, even if the mark becomes thick due to crushing or bleeding of ink at the time of printing, this thickening is uniform over the entire 360 degrees of the mark. If the difference between the major axis and the minor axis of the printed mark is measured and the difference between the two is detected, the presence / absence, amount, and direction of the double can be easily and accurately detected, and prompt measures can be taken.
[0048]
In addition, a group of double detection marks is used to measure a plurality of marks even if a single mark is not actually detected due to blurring or the like even though doubles actually occur. You will not miss it.
[0049]
According to the doubling measurement device of the present invention, the doubling amount and the direction can be automatically measured with high accuracy.
[Brief description of the drawings]
FIG. 1 is a diagram illustrating a double detection mark according to an embodiment of the present invention.
FIG. 2 is an explanatory diagram for detecting a doubling amount and a direction by using a doubling detection mark of the present invention.
FIG. 3 is an explanatory view of a multicolor double detection mark group of the present invention.
FIG. 4 is an explanatory diagram of a monochromatic double detection mark group of the present invention.
FIG. 5 is an explanatory diagram of a double detection mark group of the present invention.
FIG. 6 is a block diagram of the doubling measurement device of the present invention.
FIG. 7 is a diagram for explaining an outline of a printing press.
FIG. 8 is a diagram for explaining the cause of the occurrence of double.
FIG. 9 is an explanatory diagram of doubling.
[Explanation of symbols]
30 center mark 31 ring-shaped mark 40 center mark 41 printed in doubling ring-shaped mark 42 printed in doubling 42 minor axis 43 major axis

Claims (10)

In a printing machine that performs multicolor printing with a plurality of units having a printing plate cylinder, the printing color of the preceding unit transferred to the plate cylinder of the succeeding unit in the succeeding unit is shifted and retransferred to printing paper. A method for detecting doubling, wherein
A small circle center mark and a ring-shaped mark concentrically surrounding the center mark form a double detection mark, and the major and minor diameters of the printed double detection mark are measured. A method for detecting a dubble, wherein the difference is set as a dubble amount. 2. The double detection method according to claim 1, wherein a direction of the major axis is a double direction. 2. The double detection method according to claim 1, wherein the minor axis and the major axis are measured as distances from the center position coordinates of the small circular center mark. The doubling detection mark is divided into a plurality of portions at a fixed angle around the center position coordinates of the center mark, and the minor axis and the major axis are measured a plurality of times from the center position coordinates within each of the divided angles to calculate an average value. The double detection method according to claim 1, wherein the maximum value of the average value is a major axis, and the minimum value is a minor axis. The double detection method according to claim 1, wherein the minor axis and the major axis are measured at an outer circumference or an inner circumference of the ring-shaped mark. 2. The double detection method according to claim 1, wherein the minor axis and the major axis are measured at the outer periphery of a small circular center mark. A small circle center mark and a ring-shaped mark concentrically surrounding the center mark are arranged to form a group by arranging a plurality of doubling detection marks, and measuring the major axis and minor axis of each of the doubling detection marks. 2. The method of detecting dubbing according to claim 1, wherein an average value of a plurality of dubbing amounts determined by a difference between the two is set as a dubbing amount. A mark printed on a printed material for use in the doubling detection method according to claim 1,
A small circle center mark and a ring mark surrounding the center mark concentrically form a double detection mark, a plurality of the same color double detection marks are arranged to form a group, and the group is printed in multiple colors. A double detection mark provided for each printing color used in the image forming apparatus. A mark printed on a printed material for use in the doubling detection method according to claim 1 ,
A small circle-shaped center mark and a ring-shaped mark concentrically surrounding the center mark form a double-mark detection mark, and the double-mark detection mark formed for each printing color used in the multicolor printing is a predetermined mark. A double-mark detection mark, which is arranged in a frame to form a multi-color double-mark detection mark, and a group is formed by arranging a plurality of the multi-color double-mark detection marks. A two-dimensional area sensor for imaging double-mark detection marks for detecting double in a printing machine that performs multi-color printing with a plurality of printing units, and means for moving the two-dimensional area sensor in two-dimensional directions, and a measurement position In the doubly measuring device which measures the amount of double in the
A storage unit for storing position coordinates of a double detection mark formed by the small circular center mark and a ring-shaped mark concentrically surrounding the center mark; and a two-dimensional moving means for moving the two-dimensional area sensor by two-dimensional moving means. After being moved to the coordinate position of the double detection mark stored in the storage unit, the two-dimensional area sensor detects the double detection mark printed on the double detection mark and measures the major axis and the minor axis of the double detection mark to measure both. When there is a difference, there is provided a control unit for setting the difference to a double amount .

Images