阅读说明：本技术 套准控制单元及多色印刷系统 (Registration control unit and multicolor printing system ) 是由 平山大介 于 2020-02-11 设计创作，主要内容包括：本发明的课题在于提供一种能够高精度地检测印刷于具有透光性的卷材上的套准标记的技术。套准控制单元(20)检测印刷于具有透光性的卷材(2)上的套准标记。套准控制单元(20)具备：光源(32),朝向卷材(2)照射光；背景部,被透射过卷材(2)的来自光源(32)的光照射；及受光元件(34),接收由套准标记及背景部反射的来自光源(32)的光。光源(32)将具有受光元件(34)的灵敏度波长范围内的波长的光照射到卷材上。套准标记及背景部中的一个为灵敏度波长范围内的波长的颜色,另一个为灵敏度波长范围外的波长的颜色。(The invention provides a technology capable of detecting a register mark printed on a light-transmitting roll material with high precision. A registration control unit (20) detects a registration mark printed on a web (2) having light transmittance. The registration control unit (20) is provided with: a light source (32) that irradiates light toward the web (2); a background section which is irradiated with light from a light source (32) transmitted through the web (2); and a light receiving element (34) for receiving the light from the light source (32) reflected by the registration mark and the background portion. A light source (32) irradiates the web with light having a wavelength within the wavelength range of sensitivity of the light receiving element (34). One of the registration mark and the background portion is a color of a wavelength within the sensitivity wavelength range, and the other is a color of a wavelength outside the sensitivity wavelength range.)

1. A registration control unit for detecting a registration mark printed on a web having light transmittance, the registration control unit comprising:

a light source that irradiates light toward the web;

a background section illuminated by light from the light source transmitted through the web; and

a light receiving element that receives light from the light source reflected by the registration mark and the background portion,

the light source irradiates light having a wavelength within a sensitivity wavelength range of the light receiving element onto the web,

one of the registration mark and the background portion is a color of a wavelength within the sensitivity wavelength range, and the other is a color of a wavelength outside the sensitivity wavelength range.

2. A registration control unit for detecting a registration mark printed on a web having light transmittance, the registration control unit comprising:

a light source that irradiates light toward the web;

a background section illuminated by light from the light source transmitted through the web; and

a light receiving element that receives light from the light source reflected by the registration mark and the background portion,

the light source irradiates light having a wavelength within a sensitivity wavelength range of the light receiving element onto the web,

one of the registration mark and the background portion is a color within a wavelength region of light irradiated from the light source, and the other is a color outside the wavelength region.

3. The registration control unit of claim 1 or 2,

the background portion has a color substantially identical to a color of a peak wavelength of light irradiated by the light source.

4. A multicolor printing system comprising the registration control unit according to any one of claims 1 to 3.

Technical Field

The invention relates to a registration control unit and a multicolor printing system.

Background

A multicolor printing system is known in which a plurality of printing units are provided along a transport path of a web serving as a medium to be printed, plate cylinders provided in the respective printing units are individually driven to rotate, and printing is sequentially performed on the web. In a multicolor printing system, register marks printed on a web are detected in each printing unit, and a deviation in printing position generated between plate cylinders is controlled based on the detection result.

Patent document 1 discloses a technique for detecting a registration mark printed on a web having light transmittance. In patent document 1, a reflective plate is provided so as to face a sensor with a web therebetween, a light emitting portion of the sensor emits light, a light receiving portion of the sensor receives reflected light reflected by a registration mark or reflected light transmitted through the web and reflected by the reflective plate, and the registration mark is detected from an intensity difference between the reflected light reflected by the registration mark and the reflected light reflected by the reflective plate.

Patent document 1: japanese laid-open patent publication No. 2007-021743

By a combination of the color of the illuminating light and the color of the registration mark, the registration mark returns a relatively strong reflected light. In this case, in the technique of patent document 1, the intensity difference between the reflected light from the registration mark and the reflected light from the reflection plate is small, and the registration mark cannot be detected with high accuracy. As a countermeasure, it is also conceivable to switch the color of the irradiation light so that the register mark returns relatively weak reflected light, but the color of the irradiation light switched is about several colors in the configuration of the sensor, and cannot be dealt with by the color of the register mark.

Disclosure of Invention

The present invention has been made in view of such circumstances, and an exemplary object of one embodiment thereof is to provide a technique capable of detecting a registration mark printed on a light-transmissive web with high accuracy.

In order to solve the above problem, a registration control unit according to an embodiment of the present invention is a registration control unit for detecting a registration mark printed on a light-transmissive web, the registration control unit including: a light source that irradiates light toward the web; a background section irradiated with light from a light source transmitted through the web; and a light receiving element for receiving the light from the light source reflected by the registration mark and the background portion. The light source irradiates the web with light having a wavelength within the sensitivity wavelength range of the light receiving element, and one of the registration mark and the background portion is colored with a wavelength within the sensitivity wavelength range and the other is colored with a wavelength outside the sensitivity wavelength range.

Another embodiment of the invention is also a registration control unit. The registration control unit is used for detecting a registration mark printed on a light-transmitting roll material, and the registration control unit includes: a light source that irradiates light toward the web; a background section irradiated with light from a light source transmitted through the web; and a light receiving element for receiving the light from the light source reflected by the registration mark and the background portion.

The light source irradiates the web with light having a wavelength within a wavelength range of sensitivity of the light receiving element, and one of the registration mark and the background portion is a color within a wavelength region of the light irradiated by the light source, and the other is a color outside the wavelength region.

Yet another embodiment of the present invention is a multicolor printing system. The multicolor printing system is provided with the registration control unit.

In addition, any combination of the above-described constituent elements or an embodiment in which the constituent elements or expressions of the present invention are replaced with each other among a method, an apparatus, a system, and the like is also effective as an embodiment of the present invention.

Effects of the invention

According to the present invention, the registration mark printed on the light-transmitting web can be detected with high accuracy.

Drawings

Fig. 1 is a diagram showing a configuration of a multicolor printing system according to an embodiment.

Fig. 2 is a block diagram showing the function and structure of the registration control unit of fig. 1.

Fig. 3 is a diagram showing an example of a relationship between a wavelength of light irradiated from the light source of the 1 st sensor in fig. 2 and a wavelength range of sensitivity of the light receiving element of the 1 st sensor in fig. 2.

Fig. 4 is a diagram showing another example of the relationship between the wavelength of light irradiated by the light source of the 1 st sensor of fig. 2 and the sensitivity wavelength range of the light receiving element of the 1 st sensor of fig. 2.

In the figure: 20-register control unit, 32-light source, 34-light receiving element, 50 a-1 st background section, 50 b-2 nd background section, 100-multicolor printing system.

Detailed Description

The present invention will be described below based on preferred embodiments with reference to the accompanying drawings. The same or equivalent constituent elements, components, and processes shown in the respective drawings are denoted by the same reference numerals, and overlapping description is appropriately omitted. The embodiments are not intended to limit the invention, but are examples, and all the features or combinations thereof described in the embodiments are not necessarily essential to the invention.

Fig. 1 is a diagram showing a configuration of a multicolor printing system 100 according to an embodiment. The multicolor printing system 100 includes a 1 st printing unit 10A, a 2 nd printing unit 10B, and a registration control unit 20. The 1 st printing unit 10A and the 2 nd printing unit 10B include a plate cylinder 11 and an impression cylinder 12, respectively. The web 2 is guided along a predetermined transport path by the guide roller 4, and is pressed against the plate cylinder 11 by the impression cylinder 12. A pattern of a color corresponding to the plate cylinder 11 and registration marks are printed on the web 2. A 1 st registration mark 6A (not shown in fig. 1) is printed in the 1 st printing unit 10A, and a 2 nd registration mark 6B (not shown in fig. 1) is printed in the 2 nd printing unit 10B. The web 2 for which the multicolor printing system 100 is directed is a web having light-transmitting properties, such as a transparent web.

The registration control unit 20 includes a 1 st sensor 30a, a 2 nd sensor 30b, a 1 st background section 50a, a 2 nd background section 50b, and a control section 40. They detect the registration marks printed on the web 2 and determine whether or not a registration deviation occurs between the 1 st printing unit 10A and the 2 nd printing unit 10B based on the detection result. In the case where the registration deviation occurs, the amount of rotation of the plate cylinder 11 is increased or decreased to eliminate the registration deviation.

Fig. 2 is a block diagram showing the function and structure of the registration control unit 20.

The 1 st background portion 50a is disposed so as to face the 1 st sensor 30a with the web 2 interposed therebetween, and more specifically, is disposed so as to be irradiated with light from the light source 32 of the 1 st sensor 30a transmitted through the web 2. The shape of the 1 st background portion 50a is not particularly limited, but in the present embodiment, it has a plate-like shape. The 1 st background portion 50a is replaceable, and as described later, a background portion adapted to detect the color of the 1 st registration mark 6A may be employed.

The 2 nd background portion 50b is disposed so as to face the 2 nd sensor 30b across the web 2, and more specifically, is disposed so as to be irradiated with light from the light source 32 of the 2 nd sensor 30b transmitted through the web 2. The shape of the 2 nd background portion 50b is not particularly limited, but in the present embodiment, it has a plate-like shape. The 2 nd background portion 50B is replaceable, and as described later, a background portion adapted to detect the color of the 2 nd registration mark 6B may be employed.

The 1 st sensor 30a and the 2 nd sensor 30b are arranged at an interval L. The interval L corresponds to the distance between the 1 st registration mark 6A and the 2 nd registration mark 6B when no registration deviation occurs.

The 1 st sensor 30a and the 2 nd sensor 30b are optical sensors, and each include a light source 32, an optical system 33, and a light receiving element 34.

The light source 32 irradiates light toward the web 2. The light source 32 illuminates, inter alia, the area through which the register mark intersects. Light emitted from the light source 32 is irradiated onto the registration mark, reflected by the registration mark, condensed by the optical system 33, and received by the light receiving element 34. Alternatively, the light emitted from the light source is transmitted through the web 2 and irradiated onto a background portion, reflected by the background portion and transmitted through the web 2 again, condensed by the optical system 33, and received by the light receiving element 34.

The optical system 33 is constructed using a known technique.

The light receiving element 34 is, for example, a diode. The light receiving element 34 converts the received light into a current signal and outputs the current signal. The magnitude of the current signal is obtained by integrating the product of the intensity of the received light and the light receiving sensitivity for each wavelength. That is, the light receiving element 34 outputs a current signal corresponding to the received light. The current signal is converted into a voltage signal by a current-voltage conversion circuit, not shown, and is output to the control unit 40.

The control section 40 includes a 1 st registration mark detection section 44a, a 2 nd registration mark detection section 44b, and a registration error control section 46.

The 1 st registration mark detecting section 44a detects the 1 st registration mark 6A based on the signal output from the 1 st sensor section 31 a. The 1 st registration mark detection unit 44a compares the signal intensity of the signal output from the 1 st sensor unit 31a with a predetermined detection threshold, and determines that the 1 st registration mark 6A is detected at that time (the 1 st registration mark 6A has reached the detection region) when the signal intensity exceeds the detection threshold, for example. The 2 nd registration mark detecting section 44B detects the 2 nd registration mark 6B based on the signal output from the 2 nd sensor section 31B. The 2 nd registration mark detection section 44b has the same configuration as the 1 st registration mark detection section 44 a.

The detection results are input from the 1 st registration mark detection unit 44a and the 2 nd registration mark detection unit 44b to the registration error control unit 46, respectively. The registration error control unit 46 determines whether or not there is a registration deviation, which is a deviation in the printing position between the plate cylinders 11, based on the detection results. As described above, since the 1 st sensor unit 31a and the 2 nd sensor unit 31B are disposed at the interval L, and the 1 st registration mark 6A and the 2 nd registration mark 6B are also printed at the interval L when no registration deviation occurs, the 1 st registration mark 6A and the 2 nd registration mark 6B are detected at substantially the same timing when no registration deviation occurs. Therefore, the registration error control unit 46 determines that no registration deviation occurs when the 1 st timing at which the 1 st registration mark 6A is detected by the 1 st registration mark detection unit 44a and the 2 nd timing at which the 2 nd registration mark 6B is detected by the 2 nd registration mark detection unit 44B are substantially the same. On the other hand, when the 1 st timing is different from the 2 nd timing, the registration error control unit 46 determines that a registration deviation corresponding to an amount obtained by multiplying the conveyance speed of the web 2 by the difference between the 1 st timing and the 2 nd timing occurs in the traveling direction.

When the registration deviation occurs, the registration error control section 46 outputs a correction signal to, for example, a drive motor (not shown) of the 2 nd printing unit 10B. The drive motor drives the plate cylinder 11 in accordance with the correction signal to correct the registration deviation. Thereby, the registration deviation of the web 2 in the traveling direction is adjusted.

The foregoing is the basic structure of the multicolor printing system 100 and its operation.

Next, the relationship among the wavelength of light emitted from the light source 32, the sensitivity wavelength range of the light receiving element 34, the color of the registration mark, and the color of the background portion will be described in detail. The sensitivity wavelength range is a range of wavelengths in which the light receiving sensitivity is equal to or higher than a predetermined 1 st threshold. The 1 st threshold value can be set as appropriate based on experimental findings. Hereinafter, the relationship among the wavelength of light irradiated from the light source 32 of the 1 st sensor 30a, the wavelength range of sensitivity of the light receiving element 34 of the 1 st sensor 30a, the color of the 1 st registration mark 6A, and the color of the 1 st background portion 50a will be described, but the same description applies to the wavelength of light irradiated from the light source 32 of the 2 nd sensor 30B, the wavelength range of sensitivity of the light receiving element 34 of the 2 nd sensor 30B, the color of the 2 nd registration mark 6B, and the color of the 2 nd background portion 50B.

However, in the light irradiated on the object, a part of the wavelength components is reflected, and the remaining wavelength components are absorbed. Which wavelength component is reflected and which wavelength component is absorbed, that is, which wavelength component has a high reflectance and which wavelength component has a low reflectance, differs depending on the color of the surface of the object. This characteristic is also referred to as spectral reflectance characteristic.

For example, in an object having a red surface, the reflectance of a wavelength component of red (long wavelength component) is high, and the reflectance of a wavelength component of blue (short wavelength component) and a wavelength component of green (medium wavelength component) is low. Therefore, when a red object is irradiated with light having a high intensity of a red wavelength component, most of the irradiated light is reflected, and thus the intensity of the reflected light is relatively high. On the other hand, when a red object is irradiated with light having a low intensity of a red wavelength component or light not containing a red wavelength component, for example, light containing only a blue wavelength component or a green wavelength component, most of the irradiated light is absorbed, and thus the intensity of reflected light is relatively low.

For example, in an object having a blue surface, the reflectance of a blue wavelength component (short wavelength component) is high, and the reflectance of a green wavelength component (medium wavelength component) and a red wavelength component (long wavelength component) is low. Therefore, when a blue object is irradiated with light having a high intensity of a blue wavelength component, most of the irradiated light is reflected, and thus the intensity of the reflected light is relatively high. On the other hand, when a blue-surfaced object is irradiated with light having a low intensity of a blue wavelength component or light not containing a blue wavelength component, for example, light containing only a green wavelength component or a red wavelength component, most of the irradiated light is absorbed, and therefore the intensity of reflected light is relatively weak.

In the present embodiment, the principle is used to detect the registration mark with high accuracy.

Fig. 3 is a diagram showing an example of the relationship between the wavelength of light irradiated from the light source 32 of the 1 st sensor 30 and the wavelength range of sensitivity of the light receiving element 34 of the 1 st sensor 30.

In the example of fig. 3, the light source 32 irradiates light of all wavelengths in the sensitive wavelength range including the light receiving element 34. That is, the wavelength region of the light irradiated by the light source 32 includes the sensitivity wavelength range of the light receiving element 34. The wavelength region of the light emitted from the light source 32 is a range of wavelength components having an intensity equal to or higher than a predetermined 2 nd threshold value among the wavelength components included in the light. The 2 nd threshold value can be set as appropriate based on the knowledge based on experiments.

In this case, if the color of the 1 st registration mark 6A is a color of a wavelength within the sensitivity wavelength range of the light receiving element 34, a color of a wavelength outside the sensitivity wavelength range is adopted in the 1 st background portion 50 a. In other words, if the color of the 1 st registration mark 6A is a color having a high reflectance of a wavelength component in the sensitivity wavelength range, the 1 st background portion 50a uses a color having a low reflectance of a wavelength component in the sensitivity wavelength range.

In this case, when light from the light source 32 is irradiated onto the 1 st registration mark 6A, the wavelength component in the sensitivity wavelength range included in the light is hardly absorbed and reflected on the 1 st registration mark 6A, and therefore the light receiving element 34 that receives the reflected light from the 1 st registration mark 6A outputs a relatively high current signal.

Further, when the light from the light source 32 is not irradiated onto the 1 st registration mark 6A but is irradiated onto the 1 st background portion 50a through the web 2, the wavelength component in the sensitivity wavelength range included in the light is hardly reflected and absorbed on the 1 st background portion 50a, and thus the wavelength component in the sensitivity wavelength range is not included in the reflected light from the 1 st background portion 50a or the intensity of the wavelength component in the sensitivity wavelength range included in the reflected light becomes low, so that the light receiving element 34 that receives the reflected light from the 1 st background portion 50a outputs only a relatively low current signal.

Therefore, the current signal generated by the reflected light from the 1 st registration mark 6A is significantly higher than the current signal generated by the reflected light from the 1 st background portion 50a, and the current signal generated by the reflected light from the 1 st registration mark 6A is conspicuous, so that the 1 st registration mark 6A can be detected with high accuracy.

On the other hand, if the color of the 1 st registration mark 6A is a color of a wavelength outside the sensitivity wavelength range of the light receiving element 34, a color of a wavelength within the sensitivity wavelength range is adopted in the 1 st background portion 50 a. In other words, if the color of the 1 st registration mark 6A is a color having a low reflectance of a wavelength component in the sensitivity wavelength range, the 1 st background portion 50a uses a color having a high reflectance of a wavelength component in the sensitivity wavelength range.

In this case, when light from the light source 32 is irradiated onto the 1 st registration mark 6A, the wavelength component in the sensitivity wavelength range included in the light is hardly reflected and absorbed by the 1 st registration mark 6A, and thus the wavelength component in the sensitivity wavelength range is not included in the reflected light from the 1 st registration mark 6A or the intensity of the wavelength component in the sensitivity wavelength range included in the reflected light becomes low, and therefore the light receiving element 34 that receives the reflected light from the 1 st registration mark 6A outputs only a relatively low current signal.

When the light from the light source 32 is transmitted through the web 2 and irradiated onto the 1 st background portion 50a, the wavelength component in the sensitivity wavelength range included in the light is hardly absorbed and reflected on the 1 st background portion 50a, and therefore the light receiving element 34 that receives the reflected light from the 1 st background portion 50a outputs a relatively high current signal.

Therefore, the current signal generated by the reflected light from the 1 st registration mark 6A is significantly lower than the current signal generated by the reflected light from the 1 st background portion 50a, and the current signal generated by the reflected light from the 1 st registration mark 6A is conspicuous, so that the 1 st registration mark 6A can be detected with high accuracy.

It is preferable that the 1 st background portion 50a is colored with a wavelength that is within the sensitivity wavelength range of the light receiving element 34 and substantially matches the peak wavelength of the light emitted from the light source 32. In this case, the difference between the current signal generated by the reflected light from the 1 st registration mark 6A and the current signal generated by the reflected light from the 1 st background portion 50a becomes larger, and therefore the 1 st registration mark 6A can be detected with higher accuracy.

Fig. 4 (a) and (b) are diagrams showing another example of the relationship between the wavelength of light irradiated from the light source 32 of the 1 st sensor 30 and the wavelength range of sensitivity of the light receiving element 34 of the 1 st sensor 30.

In the example of fig. 4 (a) and (b), the light source 32 irradiates light including a part of wavelengths in the sensitivity wavelength range of the light receiving element 34. This relationship is likely to be achieved when the wavelength range of sensitivity of the light receiving element 34 is relatively large, for example, when the light receiving element 34 is an RGB diode.

In this case, if the color of the 1 st registration mark 6A is a color of a wavelength within the wavelength range of the light irradiated from the light source 32 in the sensitivity wavelength range of the light receiving element 34, that is, the wavelength range R₁The color of the wavelength within the range is the wavelength range R, which is the color of the wavelength outside the wavelength range of the sensitivity of the light receiving element 34 and/or the wavelength outside the wavelength range of the light irradiated from the light source 32, in the 1 st background part 50a₂The color of the wavelength within. In other words, if the color of the 1 st registration mark 6A is a color having a high reflectance of a wavelength component in the sensitivity wavelength range and a wavelength in the wavelength region of the light irradiated from the light source 32, the color having a low reflectance of a wavelength component in the sensitivity wavelength range and/or the color having a wavelength outside the wavelength region of the light irradiated from the light source 32 are used in the 1 st background part 50 a.

In this case, when light from the light source 32 is irradiated onto the 1 st registration mark 6A, the wavelength component in the sensitivity wavelength range included in the light is hardly absorbed and reflected on the 1 st registration mark 6A, and therefore the light receiving element 34 that receives the reflected light from the 1 st registration mark 6A outputs a relatively high current signal.

When the light from the light source 32 is transmitted through the web 2 and irradiated onto the 1 st background portion 50a, the wavelength component in the sensitivity wavelength range included in the light is hardly reflected and absorbed by the 1 st background portion 50a, and thus the wavelength component in the sensitivity wavelength range is not included in the reflected light from the 1 st background portion 50a or the intensity of the wavelength component in the sensitivity wavelength range included in the reflected light becomes low, so that the light receiving element 34 that receives the reflected light from the 1 st background portion 50a outputs only a relatively low current signal.

Therefore, the current signal generated by the reflected light from the 1 st registration mark 6A is significantly higher than the current signal generated by the reflected light from the 1 st background portion 50a, and the current signal generated by the reflected light from the 1 st registration mark 6A is conspicuous, so that the 1 st registration mark 6A can be detected with high accuracy.

On the other hand, if the color of the 1 st registration mark 6A is a color of a wavelength outside the wavelength range of the sensitivity of the light receiving element 34 and/or a wavelength outside the wavelength range of the light irradiated from the light source 32, that is, the wavelength range R₂The color of the wavelength within the range is adopted in the 1 st background part 50a as the color of the wavelength within the wavelength range of the light irradiated from the light source 32 within the sensitivity wavelength range, that is, the wavelength range R₁The color of the wavelength within. In other words, if the color of the 1 st registration mark 6A is a color having a low reflectance of the light of the wavelength component in the sensitivity wavelength range and/or a color having a wavelength outside the wavelength region of the light irradiated by the light source 32, the 1 st background portion 50a uses a color having a high reflectance of the wavelength component in the sensitivity wavelength range and a wavelength within the wavelength region of the light irradiated by the light source 32.

In this case, when light from the light source 32 is irradiated onto the 1 st registration mark 6A, the wavelength component in the sensitivity wavelength range included in the light is hardly reflected and absorbed by the 1 st registration mark 6A, and thus the wavelength component in the sensitivity wavelength range is not included in the reflected light from the 1 st registration mark 6A or the intensity of the wavelength component in the sensitivity wavelength range included in the reflected light becomes low, and therefore the light receiving element 34 that receives the reflected light from the 1 st registration mark 6A outputs only a relatively low current signal.

In this case, when the light from the light source 32 is transmitted through the web 2 and irradiated onto the 1 st background portion 50a, the wavelength component in the sensitivity wavelength range included in the light is reflected on the 1 st background portion 50a with almost no absorption, and therefore the light receiving element 34 receiving the reflected light from the 1 st background portion 50a outputs a relatively high current signal.

Therefore, the current signal generated by the reflected light from the 1 st registration mark 6A is significantly lower than the current signal generated by the reflected light from the 1 st background portion 50a, and the current signal generated by the reflected light from the 1 st registration mark 6A is conspicuous, so that the 1 st registration mark 6A can be detected with high accuracy.

It is preferable that the 1 st background portion 50a is colored with a wavelength that is within the sensitivity wavelength range of the light receiving element 34 and substantially matches the peak wavelength of the light emitted from the light source 32. In this case, the difference between the current signal generated by the reflected light from the 1 st registration mark 6A and the current signal generated by the reflected light from the 1 st background portion 50a becomes larger, and therefore the 1 st registration mark 6A can be detected with higher accuracy.

The configuration and operation of the multicolor printing system according to the embodiment are explained above. These embodiments are illustrative and one skilled in the art will appreciate that: various modifications can be made to the combination of these respective constituent elements, and such modifications are also within the scope of the present invention.