JPH09226097A - Device for detecting print registration and print registration adjusting device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To freely set a spectral sensitivity and thereby increase a detection accuracy by weighting and adding output signals generated by plural detection parts with varying spectral sensitivity in a registration mark detector with the help of a mixture calculator to output a mixture amount, and outputting a registration shift amount based on the mixture quantity using a registration shift calculator. SOLUTION: A mixture calculator 2 for a registration mark detector 1 weights signals generated by CCD line sensors 15, 16, 17 and entered through amplifiers 18, 19, 20 by specified factors and adds these weighted signals, and outputs a mixture amount. Next, this amount is stored in memory, then the sum of three products of digital data on the mixture amount and factors is calculated to obtain a mixture amount which is in turn, output. The mixture calculator 2 selects the factors by a rotary encoder pulse which is output by a rotary encoder 6. This mixture amount is entered to a registration shift calculator 3 to output a registration shift amount. Further, the calculator 3 determines which part of printed matter is represented by the mixture amount using the output pulse from the rotary encoder 6, and image data on the registration mark is reproduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technical field of detecting and adjusting a print register from a register mark printed on a multicolor printing machine. In particular, the present invention relates to a printing register detecting device and a printing register adjusting device that can appropriately set detection conditions even when the spectral characteristics of the register mark are diverse due to the use of various types of printing ink.

[0002]

2. Description of the Related Art Overprinting is performed in multicolor printing, and it is said that the registration of printed images is aligned during this overprinting. Visual registration is one of the methods for registering. This is a method in which a printing operator checks a cross-shaped register mark, which is called a register mark, printed on a margin of a printing sheet with a naked eye or a loupe and adjusts the printing machine. The registration marks are inserted in advance in the printing original plates of the respective colors so that the registration marks of the respective colors are completely overlapped, and the necessity of the register adjustment and the coping method are determined based on the overlapping degree of the printed registration marks. Another method of registering is registering by an automatic device. For example, as disclosed in Japanese Patent Application No. 43-49490, a register mark of the same shape is arranged in a margin of a printing paper at a constant interval for each color, and the interval between the register marks is detected by a detector. In this method, the register shift amount is calculated from the detection signal and the register shift is automatically corrected.

In the above automatic registration device, the register mark detector has a white light source and a light receiving element such as a photoelectric tube or a photodiode paired with the white light source. The light from the light source illuminates the blank area of the printing paper on which the register mark is printed, and the light receiving element receives the reflected light and outputs a signal. The presence or absence of the register mark is detected from the change in the output signal. By the way, the ink used for printing is
In addition to the four colors of yellow, magenta, cyan, and black, which are called process ink colors, there is an ink called special color ink in which special pigments are mixed. Therefore, the spectral characteristics of the ink are extremely diverse and change, and it is assumed that the ink colors include all colors in the visible region. Therefore, to ensure that the wavelength range of light that can be detected by the register mark detector includes the entire visible range, the light source emits all wavelengths in the visible range, and the light receiving element emits all wavelengths in the visible range. A material having sensitivity is used.

[0004]

By making it possible to detect light of all wavelengths in the visible region in this way, for a specific ink color, the detection signal is biased (raised) by light outside the absorption wavelength region. Therefore, it generally means that the sensitivity is lowered. Even in this case, it is possible to detect a register mark printed with an ink having a relatively high density such as magenta or cyan without any problem. However, when printed with light-colored ink having a relatively low density such as yellow or pink, the detection signal of the register mark becomes very small, and it is difficult to distinguish it from the noise included in the bias. Therefore, the detection becomes unstable or impossible, and the inconvenience that the registration cannot be performed automatically occurs. To alleviate this problem, a method of detecting a register mark by changing the light amount balance of a light receiving element having sensitivity in two divided visible regions is disclosed in JP-A-49-1216.
No. 05 publication. However, it is not practical because initial adjustment according to the background color is required, and it is not effective for ink colors having a spectral characteristic that extends into two visible regions.

Of course, it is conceivable to prepare a detector having sensitivity corresponding to the absorption wavelength region of the ink for each ink and replace the detector according to the ink used for printing, but the preparation work for replacement is complicated. And this is also not realistic. Therefore, an object of the present invention is to provide a printing register in which the spectral sensitivity can be freely and easily set for a detector having sensitivity in the entire visible region so as to have sensitivity matching the absorption wavelength range of ink. An object is to provide a detection device and a printing register adjustment device.

[0006]

In order to solve the above-mentioned problems, in the present invention, a register mark detector in which a plurality of detection portions having different spectral sensitivities output independent signals, and a plurality of the detection portions output. A mixing operation unit for weighting signals to be added by a predetermined coefficient and adding the signals to output a mixing amount;
A register shift calculator that outputs a register shift amount based on the mixing amount, and the predetermined coefficient can be set freely and easily.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to embodiments. First, the print registration detecting device of the present invention will be described. The printing register detecting device of the present invention includes at least a register mark detector, a mixing calculator, and a register shift calculator. Then, the register mark detector outputs a signal in which a plurality of detection portions having different spectral sensitivities are independent. Also,
The mixing calculator weights the signals output by the plurality of detection portions with a predetermined coefficient, adds the signals, and outputs a mixing amount. Therefore, signals in the absorption wavelength range of the register mark can be selected from the signals output from the plurality of detection portions, or mixed and used, and signal components that do not contribute to the detection of the register mark can be removed. it can. The register shift calculator outputs the register shift amount based on the mixing amount.

As described above, according to the printing register detecting apparatus of the present invention, each detection portion of the detector having the sensitivity in the entire visible region is weighted so as to have the sensitivity corresponding to the absorption wavelength region of the ink. By adding, the spectral sensitivity can be set freely and easily. As a result, the register mark printed with light-colored ink with low density can be separated from the noise included in the bias to increase the S / N ratio of the detection signal, and a highly reliable register shift amount can be detected. it can.

In the printing register detecting apparatus of the present invention, the detecting portion of the above-mentioned register mark detector has an illumination element and an image pickup element, and the register shift calculator is image data of the register mark imaged by the image pickup element. Then, the coordinate value of the center of gravity is calculated, and the register shift amount is output according to the shift of the coordinate value.
A so-called white light source such as a halogen lamp, a xenon lamp, a fluorescent lamp, or the like can be used as the lighting element. An imaging device such as a CCD line sensor or a CCD image sensor can be used as the imaging element. Then, a color filter, an interference filter, a dichroic filter, or the like is inserted into the imaging optical system in order to give different detection areas different spectral sensitivities. The misregistration calculator calculates the coordinates of the center of gravity after binarizing the mixing amount output from the mixing calculator to obtain binary image data. The coordinates of the center of gravity can be calculated by a microcomputer or the like, and the details thereof are well known in the art, so that the description thereof will be omitted.

According to the printing register detecting apparatus of the present invention, since the position of the register mark is calculated as the coordinates of the center of gravity thereof from the image information of the entire register mark in this manner, it is resistant to disturbances such as noise and printing defects. The reliability is high and the position data detection accuracy is high.

Further, in the printing register detecting apparatus of the present invention, the above-mentioned mixing calculator has a coefficient storage element and a selection element. The coefficient storage element stores a plurality of coefficients for weighting. The selection element selects one from the plurality of coefficients stored in the coefficient storage element. The selected coefficient is used as a coefficient when calculation is performed by (the calculation element of) the mixing calculation unit. This mixed computing unit can be realized by a pure hardware configuration including a latch and a register for temporarily storing data and a multiplier and an adder. It can also be realized by a microcomputer. Since the configuration of the arithmetic unit when an arithmetic expression is given is a well-known technique, detailed description thereof will be omitted. The general expression in the above calculation is given by the following mathematical expression 1 (sum of products calculation).

[0012]

## EQU1 ## c = a1 * x1 + a2 * x2 +
.. + + an * xn where c; mixing amount an; coefficient (real number) xn; output of imaging element n; integer (1, 2, 3, ...)

As described above, according to the printing register detecting apparatus of the present invention, the register mark detector installed in the printing unit remains unchanged, and various ink colors can be obtained by simply changing the coefficient used in the mixing calculator. It can be set so that the optimum detection is performed on the registration mark. Therefore, even if the ink color of the register mark changes, it can be easily dealt with.

Further, in the print register detecting apparatus of the present invention, the above-mentioned mixing arithmetic unit has a communication element, and the communication element sets a coefficient for weighting in the coefficient storage element based on input data. . Therefore, when presetting the various functions of the printing machine according to the print item, it is possible to remotely set the coefficients used in the mixing calculator together with the data setting.

Further, in the printing register detecting apparatus of the present invention, the above-mentioned selection element is a selection element for changing the coefficient to be selected according to the print timing from among the plurality of coefficients stored in the coefficient storage element. Since this coefficient change is performed electronically in accordance with the print timing and is fast, the register mark printed on the upstream unit can also be detected to detect the relative register mark position. High accuracy.

Further, in the print registration detecting apparatus of the present invention, the above-mentioned communication element sets selection data in which the relationship between the print timing and the coefficient to be selected is described, in the selection element, based on the input data. Therefore, when presetting the various functions of the printing press according to the printing item, it is possible to set the selection data together with the data setting.

Next, the printing register adjusting device of the present invention will be described. The printing register adjusting device of the present invention includes at least a register mark detector, a mixing calculator, a register shift calculator,
It has a control circuit, a vertical register adjuster, and a left and right register adjuster. In the register mark detector described above, a plurality of detection portions having different spectral sensitivities output independent signals. The above-mentioned mixing calculator weights the signals output from the plurality of detection portions with a predetermined coefficient, adds the signals, and outputs the mixing amount. The misregistration calculator outputs the misregistration amount based on the mixing amount. The control circuit outputs the operation amount for adjusting the register shift based on the register shift amount. The above-mentioned top-and-bottom register adjuster adjusts the register shift in the direction parallel to the transfer direction of the printing paper based on the operation amount. The left and right register adjuster adjusts the register shift in the direction perpendicular to the transport direction of the printing paper based on the operation amount.

As is apparent from the above, the printing register adjusting device of the present invention is a device in which a control circuit, a top and bottom register adjusting device, and a left and right register adjusting device are added to the above-described printing register detecting device of the present invention. . In the printing register adjusting device of the present invention,
The control circuit gives a manipulated variable to the register shift amount, and its control operation can be represented by a functional relationship between the register shift amount and the manipulated variable. The control operation is a binary operation in which the operation amount takes one of two fixed values, a multi-value operation in which the operation amount takes one of three or more fixed values, and the operation amount is the current value of the misregistration amount. Known are a proportional proportional operation, an integral operation in which the operation amount is proportional to an integral value of the misregistration amount, a differential operation in which the operation amount is proportional to a differential value of the misregistration amount, and the like. Also in the present invention, one of those control operations or a combination thereof can be used.

Further, in the printing register adjusting device of the present invention, the top-bottom register adjuster is a gravure printing machine, and in the gravure printing machine, it is provided with a registering roller and a moving mechanism for correcting the positional relationship between the units of the printing paper. Further, the offset printing machine is constituted by a phase adjusting mechanism for changing the rotational phase of the plate cylinder. The left / right register adjuster is a mechanism for moving the plate cylinder in the left / right direction. According to the printing register adjusting device of the present invention, the register adjustment is highly reliable and accurate even when the register mark is printed with a light ink having a low density.

[0020]

EXAMPLES The present invention will be described below with reference to examples. FIG. 1 is a diagram showing the configuration of a printing register detecting apparatus according to the present invention. In FIG. 1, 1 is a register mark detector, 2 is a mixing calculator, 3 is a register calculator, 4 is L such as Ethernet.
AN (local area network), 5 is a computer such as a personal computer or a workstation connected to the LAN 4, 6 is a rotary encoder for outputting the traveling information of the printing paper, and 7 is the paper surface of the printing paper. In addition, the register mark detector 1 is composed of further details.
Is a white light source, 9 is a lens for imaging, 10 and 11 are half mirrors, 12 is an optical filter R that transmits red light,
13 is an optical filter G that transmits green light, 14 is an optical filter B that transmits blue light, and 15 is C that images red light.
CD line sensor camera, 16 CC for capturing green light
D line sensor camera, 17 is a CCD for capturing blue light
Line sensor camera, 18 is an amplifier for red image pickup signal, 1
Reference numeral 9 is a green image pickup signal amplifier, 20 is a green image pickup signal amplifier, and 21 is a drive circuit of the CCD line sensor camera.

The operation of the above structure will be described below. In order to detect the register mark printed on the margin portion of the printing paper, the white light source 8 illuminates the margin portion (paper surface 7) on which the register mark is printed. The illuminated portion of the paper surface 7 changes as the printing paper is transported. Image information is read by performing main scanning by the CCD line sensor described below and performing sub-scanning by the transfer of the printing paper. The light reflected from the paper surface 7 passes through the imaging lens 9, and the light flux is divided into three by the half mirror 10 and the half mirror 11. One of the divided light beams forms an image on the CCD line sensor 15 via the filter R12 which transmits red light, and one of the divided light beams forms on the CCD line sensor 16 via the filter G13 which transmits green light. One of the image-formed and divided light beams forms an image in the CCD line sensor 17 through the filter B14 that transmits blue light. As a result, the CCD line sensor 15 has a spectral sensitivity to red light, and the CCD line sensor 1
6 has a spectral sensitivity to green light, and a CCD line sensor 17
Has a spectral sensitivity to blue light.

The CCD line sensors 15, 16 and 17 are C
It is driven by the CD line sensor drive circuit 21, and the CCD line sensor drive circuit 21 inputs a rotary encoder pulse. The rotary encoder 6 is connected to a driving shaft of a printing machine or the like, and a rotary encoder pulse output from the rotary encoder 6 gives a print timing. That is, the CCD line sensor drive circuit 21 is controlled so that the CCD line sensors 15, 16 and 17 read the paper surface 7 in synchronization with the print timing.
Drive the CD line sensor. By synchronizing with the print timing, it is possible to read a predetermined print portion at a predetermined timing, regardless of fluctuations in the print speed. This CC
The signals output from the D line sensors 15, 16 and 17 are input, the amplifiers 18, 19 and 20 amplify and output to the mixing calculator 2.

The mixing calculator 2 inputs the signals output from the CCD line sensors 15, 16 and 17 via the amplifiers 18, 19 and 20, weights these signals with a predetermined coefficient and adds them to obtain the mixing amount. Output. Mixed computing unit 2
When the signals output from the CCD line sensors 15, 16 and 17 are input, the analog signals are A / D converted into digital data and stored in memories such as latches and registers. On the other hand, a predetermined coefficient is selected by a selection element (see FIG. 4) from the coefficients stored in the coefficient storage element (see FIG. 4) and is also stored in a memory such as a latch or a register. CCD line sensor 1 stored in memory
Three products of the digital data of 5, 16, and 17 and the coefficient are calculated, and when the sum of these three products is calculated, the mixing amount is obtained, and the mixing amount is output. This calculation is performed by the calculation element of the mixing calculator 2 (see FIG. 4).

The coefficient stored in the coefficient storage element of the mixing calculator 2 is set by the data transferred from the computer 5 through the LAN 4. The selection element of the mixing calculator 2 selects the coefficient specified by the print timing given by the rotary encoder pulse output from the rotary encoder 6. It is determined by this printing timing that the register mark of a specific color is included in the detection area of the CCD line sensor, and the optimum coefficient for detecting the register mark of that color is selected. Selection data describing the relationship between the print timing and the coefficient to be selected (see FIG. 4).
From the computer 5 as in the above-mentioned coefficient.
The data transferred through N4 is set.

The register shift calculator 3 inputs the mixing amount output from the mixing calculator 2 and outputs the register shift amount. The misregistration calculator 3 receives the rotary encoder pulse output from the rotary encoder 6, and can determine which part of the printed material is obtained by picking up the input mixing amount. Therefore, the register shift calculator 3 can reproduce the image data of the register mark based on the mixing amount. The mixed amount is, for example, 1-byte multivalued data, so that the image data of the binary register mark is binarized, the center of gravity of the binary register mark is calculated, and the coordinates of the center of gravity are used as the position coordinates of the register mark. To do. The register shift amount is calculated by comparing this coordinate with the coordinate of the register mark of the upstream printing unit and calculating the shift from the case where the register is correct.

Next, details of each part will be described with reference to the drawings. FIG. 2 is a diagram showing an example of the register mark detector of the present invention. 2, the same parts as those in FIG. 1 are given the same names. Hereinafter, the same applies to the drawings for explaining the present invention. In FIG. 2, 1 is a register mark detector, 7 is a paper surface,
8 is a light source, 9 is a lens, 22 is a first color register mark,
Reference numeral 23 is a second color register mark. In the register mark detector 1 shown in FIG. 2, the CCD line sensor and the like in the configuration shown in FIG. 1 are omitted. As shown in FIG.
The register mark detector 1 detects the register mark 22 of the first color.
Has been detected. As is clear from the transport direction of the paper indicated by the arrow ←, after the first-color register mark 22 is detected, the second-color register mark 23 is detected in the same optical system of the register mark detector 1. It

When the detection is performed as described above, the mixing amount corresponding to the detection of the two registration marks is input to the register shift calculator 3 through the mixing calculator 2 in time series. With respect to the mixing amount input in this time series, the coordinate value in the traveling direction (sub-scanning direction) of the paper surface is calculated by the rotary encoder pulse output from the rotary encoder 6, and the same coordinate value is input. The coordinate value in the scanning direction (main scanning direction) of the CCD line sensor is calculated depending on whether the mixing amount is a certain amount. FIG. 3 is a diagram for explaining a method of calculating the register shift amount from the center of gravity of two register marks performed in the register shift calculator 3. As shown in FIG. 3, assuming that the x-axis is the traveling direction of the paper surface (sub-scanning direction) and the y-axis is the scanning direction (main scanning direction) of the CCD line sensor, the registration is based on the mixing amount input in time series. The image data of the mark can be reproduced. Since the mixture amount input to simplify the calculation of the center of gravity is binarized (see the description of the center of gravity in FIG. 1), the register mark is reproduced as binary image data.

It is assumed that the coordinates of the center of gravity of the register mark 22 of the first color are (G1x, G1y) and the coordinates of the center of gravity of the register mark 23 of the second color are (G2x, G2y). The upside-down registration amount, which is the upside-down registration amount that is parallel to the printing paper transfer direction, and the left-right registration error that is the left-right registration error amount, which is the direction perpendicular to the printing paper transfer direction. It can be calculated by the following equation 2.

[Equation 2] (Regular misalignment amount) = G1x-G2x
+ ΔX (left / right register misalignment amount) = G1y−G2y where ΔX; regular distance between the first and second color registration marks

In the above description, the first color and second color register marks have been described for the sake of convenience of description, but they are referred to as the second and third color register marks, and the third and fourth color register marks. It goes without saying that the same holds true for the adjacent upstream and downstream register marks.

Next, the mixing calculator will be described. FIG.
FIG. 3 is a diagram showing a configuration of a mixing arithmetic unit in functional blocks. In FIG. 4, 2 is a mixed computing unit, 41 is a computing element of the mixed computing unit 2, 42 is a coefficient storage element of the mixed computing unit 2, 43 is a selection element of the mixed computing unit 2, 44 is a communication element of the mixed computing unit 2. Is. As shown in FIG. 4, the mixing arithmetic unit 2 includes an amplifier 1
Signals R, 8 and 19 output from CCD line sensors 15, 16 and 17 (see FIG. 1) via
Enter G and B. The calculation element 41 is composed of signals R, G, B,
Based on the coefficients r, g, b selected by the selection element 43 from the coefficients stored in the coefficient storage element 42, the following formula 3
The calculation represented by the equation is performed and the mixed amount c is output.

## EQU00003 ## c = r * R + g * G + b * B

This calculation is performed by the signals R, G, and
Although B is converted into digital data and digital calculation is performed, analog calculation may be performed. Whether to perform the digital calculation or the analog calculation is a design item that is performed in consideration of the obtained performance and the economical efficiency when the device is realized. Either case is within the scope of the embodiments of the present invention, and the present invention includes them.

The coefficient is a vector and has the same number of components as the number of detecting portions of the register mark detector. In the above example, the number of components is three (r, g, b), but it goes without saying that the spectral sensitivity of the detection unit of the register mark detector can be subdivided. If subdivided, detection performance is improved for register marks of various printing colors. On the other hand, the signal (R, G, B) is also a vector, and Equation 3 is a scalar product of the coefficient vector (r, g, b) and the signal vector (R, G, B). If subdivided, the number of components is not limited to three, so in general,
It is represented by the above-described formula of Formula 1.

The coefficient storage element 42 stores a plurality of coefficients. In FIG. 4, (coefficient 1) = (r1, g1, b
1), (coefficient 2) = (r2, g2, b2), (coefficient 3)
= (R3, g3, b3), (coefficient 4) = (r4, g4
Coefficients such as b4) are stored. This coefficient is determined to have sensitivity in the light absorption wavelength range of the register mark to be detected. That is, of the coefficient components, the absorption wavelength band component has a large value, and within the coefficient component, the non-absorption wavelength band component has a small value or zero.

When the print timing is input, the selection element 43 refers to the selection data, selects the coefficient set in the calculation element 41 at the print timing from the coefficients stored in the coefficient storage element 42, and sets it in the calculation element 41. To do. The printing timing in this case gives the timing before the register mark is detected by the register mark detector.When multiple register marks are detected by the register mark detector, the register marks are registered for each register mark. The timing before the mark is detected is given.

The communication element 44 has an interface function for performing data communication between the mixed computing unit 2 and an external device. Although FIG. 1 shows an example in which the computer 5 is connected via the LAN 4, RS232C, IEEE
It may be another interface such as E488 or SCSI. The communication element 44 has a function as such an interface, and the coefficient is stored in the coefficient storage element 42 based on the data input through the interface.
It has a function of setting selection data in the selection element 43.

Now, the printing register adjusting apparatus of the present invention will be described. As described above, the printing register adjusting device of the present invention is a device obtained by adding the control circuit, the top and bottom register adjusting device, and the left and right register adjusting device to the above-described printing register detecting device of the present invention. Therefore, only those adjustment parts will be described. FIG. 5 is a view showing an adjusting portion of the print register adjusting apparatus. In FIG. 5, reference numeral 51 is a control circuit, 52 is a motor drive circuit, 53 is a vertical correction motor, 54 is a compensator roller, 55 is a left and right correction motor, and 56 is a plate cylinder.

As shown in FIG. 5, the control circuit 51 inputs the register shift amount output from the register shift calculator (see FIG. 1). When the register shift amount is input, the control circuit 51 outputs the adjustment amount to the motor drive circuit 52 according to a predetermined control operation. When the adjustment amount is input, the motor drive circuit 52 drives the correction motor so as to correct the misregistration amount. The correction motor includes an up-and-down correction motor 53 that corrects in the up-and-down direction (direction parallel to the printing paper transfer direction) and a left-and-right correction motor 55 that performs correction in the left-right direction (direction perpendicular to the printing-paper transfer direction).
According to the adjustment amount, both or one of the correction motors is driven. The up-and-down correction motor 53 adjusts the position of the compensator roller 54 of the printing machine in the direction perpendicular to the axis of the compensator roller 54, and corrects the misalignment in the up-and-down direction by correcting the path length of the printing paper between the printing units. The left / right correction motor 55 adjusts the position of the plate cylinder 56 of the printing machine in a direction parallel to the axis of the plate cylinder 56 to correct the lateral misregistration.

Next, a modification of the above embodiment will be described. FIG. 6 is a diagram showing a modified example of the register mark detector. In FIG. 6, 61 is a paper surface, 62a and 62b are white light sources, 63
a, 63b are lenses, 64a, 64b, 65a, 65b
Is a dichroic mirror, 66a, 66b, 67a, 6
7b, 68a and 68b are photodiodes. The paper surface 61 is illuminated by the light projected from the light sources 62a and 62b, and part of the light reflected on the paper surface 61 is reflected by the lens 6
It is condensed by 3a and 63b and reaches the dichroic mirrors 64a and 64b. Dichroic mirror 64
Reference numerals a and 64b are mirrors that utilize the interference of light and have the property of reflecting light of a specific wavelength and transmitting light of another wavelength. The dichroic mirrors 64a and 64b are R (red)
Light reflected by the photodiode 66a,
The light is received at 66b. Dichroic mirror 64
The light transmitted through a and 64b is the dichroic mirror 65.
reach a, 65b. Dichroic mirrors 65a, 6
5b reflects G (green) light, and the reflected light is received by the photodiodes 67a and 67b. The light transmitted through the dichroic mirrors 65a and 645 is blue light because red and green are removed, and the light is received by the photodiodes 68a and 68b.

As is clear from the figure and the description, the register mark detector shown in FIG. 6 is composed of a pair of detectors of a set with a number "a" and a set with a number "b". Has been done. The pair of detectors are provided at a distance corresponding to the distance between the pair of register marks when there is no misregistration. Therefore, when there is no misregistration, the pair of registration marks are detected at the same time, so that there is no delay or advance in the detection time (zero position method). On the other hand, if there is misregistration, it can be detected as a delay or advance of the detection time, and the detection sensitivity is high. Also, compared to the register mark detector of FIG. 1, a dichroic mirror is used instead of the color filter and a photodiode is used instead of the CCD line sensor.

A method for detecting misregistration by the zero-position method, which has two sets of detectors in one register mark detector as shown in FIG. 6, is mainly used in a multicolor gravure rotary printing machine. used. In this case, the register mark detectors are installed in the respective printing units of the second and subsequent colors, and the register mark detector installed in the Nth unit is the Nth unit by the detector with the number "a" in FIG. -1 unit detects the registration mark printed, and the number is "b"
The register mark printed by the Nth unit is detected by the detector marked with. At that time, in order to detect only the target mark, set the period during which the target mark passes the detection area of the detector based on the print timing signal of the rotary encoder, and only the detection signal of the set period is set. Is processed. In the case of this method, each register mark detector only detects a register mark of a specific color while a certain pattern is being printed, so it is not necessary to switch the coefficient at each detection in the mixing calculator. Absent. Therefore, by setting the coefficient before the printing is started, it is not necessary to change the coefficient thereafter until the printing is completed.

FIG. 7 is a diagram showing a modification of the mixing arithmetic unit. In FIG. 6, 71a and 71b are color selection switches,
72a and 72b are coders, and 73a and 73b are analog switches. The selection switches 71a and 71b have a position to be selected corresponding to the print color of the register mark, and a position matching the print color of the register mark to be detected is selected.
When this selection is made, the coders 72a and 72b convert the coded selection signals to the analog switches 73a and 73b. On the other hand, the analog switches 73a and 73b are supplied with output signals from a plurality of detection units of the register mark detector, and only the selected output signal is output from the analog switches 73a and 73b based on the coded selection signal. Is output. As described above, the mixing calculator shown in FIG. 7 is a simple selection switcher having a coefficient of "0" or "1".

[0042]

As described above, according to the printing register detecting apparatus of the present invention of the present invention, each of the detectors having sensitivity in the entire visible region has sensitivity corresponding to the absorption wavelength region of ink. The spectral sensitivity can be freely and easily set by weighting and adding the detected portions.
As a result, the register mark printed with light-colored ink with low density can be separated from the noise included in the bias to increase the S / N ratio of the detection signal, and a highly reliable register shift amount can be detected. it can. Further, the detection portion of the register mark detector has an illumination element and an image pickup element, and the register shift calculator calculates the coordinate value of the center of gravity from the image data of the register mark imaged by the image pickup element, and the coordinate value thereof. According to the printing registration detecting apparatus of the present invention which outputs the registration deviation amount according to the deviation of the registration mark, the position of the registration mark is calculated as the coordinates of its center of gravity from the image information of the entire registration mark, and therefore disturbances such as noise and printing defects are generated. Strong, reliable, and highly accurate in detecting position data.

Further, according to the print register detecting apparatus of the present invention in which the mixing calculator has the coefficient storage element and the selection element, the register mark detector installed in the printing unit remains as it is and the coefficient used in the mixing calculator. It is possible to set so that optimum detection can be performed for register marks of various ink colors by simply changing. Therefore, even if the ink color of the register mark changes, it can be easily dealt with. Further, according to the print register detecting apparatus of the present invention, in which the mixing arithmetic unit has a communication element, and the communication element sets the coefficient for weighting in the coefficient storage element based on the input data, Accordingly, when presetting various functions of the printing press, it is possible to remotely set the coefficients used in the mixing calculator together with the data settings.

Further, according to the print register detecting apparatus of the present invention, the selection element is a selection element for changing the coefficient selected from the plurality of coefficients stored in the coefficient storage element according to the print timing. Since it is performed electronically in accordance with the printing timing and is high-speed, the register mark printed by the upstream unit can also be detected to detect the relative position of the register mark, and the position detection accuracy is high. Further, according to the print register detection apparatus of the present invention, which sets the selection data in which the relationship between the print timing and the coefficient to be selected is described as the selection element based on the data input by the communication element,
When presetting the various functions of the printing press according to the print item, it is possible to set the selection data together with the data settings thereof.

Further, according to the printing register adjusting apparatus of the present invention, the register adjusting is highly reliable and accurate even when the register mark is printed with a light color ink.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of a print register detection apparatus of the present invention.

FIG. 2 is a diagram showing an example of a register mark detector of the present invention.

FIG. 3 is a diagram illustrating a method of calculating a register shift amount from a center of gravity of two register marks, which is performed in a register shift calculator.

FIG. 4 is a block diagram showing the configuration of a mixing calculator.

FIG. 5 is a diagram showing an adjusting portion of the print register adjusting apparatus.

FIG. 6 is a diagram showing a modification of the register mark detector.

FIG. 7 is a diagram showing a modified example of a mixing calculator.

[Explanation of symbols]

1 Register mark detector 2 Mixing calculator 3 Register shift calculator 4 LAN 5 Computer 6 Rotary encoder 7 Paper surface 8 Light source 9 Lens 10, 11 Half mirror 12 Filter R 13 Filter G 14 Filter B 15, 16, 17 CCD line sensor 18 , 19, 20 Amplifier 21 CCD line sensor drive circuit 22 First color register mark 23 Second color register mark 41 Calculation element 42 Coefficient storage element 43 Selection element 44 Communication element 51 Control circuit 52 Motor drive circuit 53 Vertical correction motor 54 Compensator roller 55 Left-right correction motor 56 Plate cylinder 61 Paper surface 62a, 62b White light source 63a, 63b Lens 64a, 64b, 65a, 65b Dichroic mirror 66a, 66b, 67a, 67b, 68a, 68b Photodiode

Claims (7)

[Claims] 1. A register mark detector in which a plurality of detection parts having different spectral sensitivities output independent signals, and signals output from the plurality of detection parts are weighted by a predetermined coefficient and added to output a mixing amount. And a register shift calculator that outputs a register shift amount based on the mixture amount. 2. The detection portion has an illumination element and an image pickup element, and the register shift calculator calculates a coordinate value of a center of gravity from image data of a register mark picked up by the image pickup element,
The print registration detecting device according to claim 1, wherein the registration deviation amount is output according to the deviation of the coordinate values. 3. The mixing arithmetic unit has a coefficient storage element for storing a plurality of coefficients for weighting, and a selection element for selecting one from a plurality of coefficients stored in the coefficient storage element. The printing register detecting device according to any one of claims 1 to 3, wherein 4. The mixing arithmetic unit has a communication element, and the communication element sets a coefficient for weighting in the coefficient storage element based on input data. Printing register detection device. 5. The printing according to claim 4, wherein the selection element is a selection element that changes a coefficient selected from among a plurality of coefficients stored in the coefficient storage element according to print timing. Register detection device. 6. The selection element according to claim 4, wherein the communication element sets selection data in which the relationship between the print timing and the coefficient to be selected is described, on the basis of the input data. Print registration detection device. 7. A register mark detector in which a plurality of detection portions having different spectral sensitivities output independent signals, and signals output from the plurality of detection portions are weighted by a predetermined coefficient and added to output a mixing amount. A mixing calculator, a register shift calculator that outputs a register shift amount based on the mixture amount, a control circuit that outputs a manipulated variable for adjusting the register shift based on the register shift amount, and the manipulated variable An up-and-down register adjuster that adjusts the register misalignment in the direction parallel to the transfer direction of the printing paper, and a left-right register adjuster that adjusts the register misalignment in the direction perpendicular to the transfer direction of the printing paper based on the operation amount. A printing register adjusting device having.