JPH05441U - Mark position detector - Google Patents

Abstract

(57) [Abstract] [Purpose] A mark position detection device capable of obtaining stable performance by switching the mark detection of a moving printed matter according to the case of irregular reflection surface and the case of near specular reflection. [Structure] The reflected light from the DUT 4 is guided to a plurality of locations, and the light receiving elements 5 are fixedly arranged at the plurality of locations, respectively, and the optimum output of the light receiving element is obtained according to the type of the DUT 4. select.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a mark position detecting device for detecting the position of a mark printed on an object to be measured such as a web.

[0002]

[Prior Art]

 In the case of performing impression printing with a plurality of plate cylinders, color misregistration occurs unless each color is printed at a fixed position. For this reason, a mark for each color is provided on the printing target (web) and printing is controlled based on this mark.

A rotary printing press will be described as an example of detecting the mark position. Fig. 2 shows the basic structure of the impression printing of an offset rotary printing press. The web 12 unwound from the supply roller 11 is a plate cylinder for black 13, a plate cylinder for blue 14, a plate cylinder for red 15, a plate for yellow. Black, blue, red, and yellow are overprinted by sequentially passing through the printing unit consisting of the cylinder 16, and a series of printing is completed. The perimeter of each plate cylinder 13, 14, 15, 16 in the printing unit is the same size, and one sheet is printed for each rotation of the plate cylinder, and the web 12 passing through the printing unit has a plate cylinder circumference. Is printed repeatedly as a unit.

When the automatic registration control for preventing color misregistration is performed by adjusting the rotation of these four plate cylinders, a register mark as shown in FIG. 3 is printed on a blank portion having no picture at the edge of the web. Each plate cylinder prints. In other words, the black register mark is performed by the black plate cylinder 13 that prints a black pattern, the blue register mark is the blue plate cylinder 14, and so on. To print.

In FIG. 3, (a) shows a case where the registration error is zero in a state where there is no print deviation of each color. The arrow indicates the traveling direction of the web 12. (B) shows the case where the red register mark is shifted to the blue side by dmm, and at this time, the red pattern is also shifted to the dmm blue side. In other words, the deviation of the pattern of each color can be measured by monitoring the relative position between the register marks.

As an apparatus for measuring the relative position between such register marks, a reflection type optical sensor or the like is used. This reflection type optical sensor converts the intensity of light scattered from the web surface into an electric signal, and outputs a signal when the register mark of each color passes the light spot portion of the optical element as the web 12 advances.

FIG. 4 is a diagram showing an optical system of the register mark detection device. Reference numeral 1 is a light source, 2 is a lens that collects the light from the light source 1, 3 is a half mirror that transmits the light and reflects and collects the light. Reference numeral 4 is a measured object such as a web. Reference numeral 5 denotes a light receiving element. The light receiving element 5 rotates about a rotation center C and receives a diffused reflected light indicated by a solid line, and a dotted line through which the specular reflected light is reflected by the half mirror 3 and passes through. It can be moved to the position shown.

If the DUT 4 is a sheet that diffusely reflects, it is better to receive the diffuse reflected light at the position indicated by the solid line, and in the case of aluminum foil, film, silver printing, etc., which is close to specular reflection, the dotted line It is better to receive the specularly reflected light at the position indicated by.

Therefore, in the conventional mark detection device, in order to correct the amount of light reflection according to the object to be measured, one light receiving element is attached to the rotary shaft, and the light receiving element is rotated to obtain the optimum detection position. Was adjusted to.

[0010]

[Problems to be solved by the device]

 Since the light receiving element is rotationally moved around the rotation axis as described above, there are the following problems. Incorrect positioning due to friction of the rotating shaft or backlash. Misalignment occurs due to vibration during use. Since the light receiving element rotates, the lead wire connected to it may be cut. Since the light-receiving element is rotated, the operator must approach the equipment while it is in operation, which is dangerous.

The present invention has been made in view of the above problems, and provides a mark position detection device having a stable performance by fixing light receiving elements to a plurality of reflected light guiding positions from an object to be measured. With the goal.

[0012]

[Means for Solving the Problems]

 In order to achieve the above object, a mark position detection device that irradiates a moving DUT that has a mark at a predetermined position with light and detects the reflected light from the mark to detect the mark position Light is guided, and light-receiving elements are provided at each of these multiple locations so that the output of the light-receiving element located at the position depending on the type of the DUT can be selected.

[0013]

[Action]

 Depending on the material of the object to be measured, the light receiving element can be fixed and attached to each optimum light receiving angle position, and the output of the light receiving element can be selected and taken out according to the object to be measured. Since the light receiving element is fixed, there will be no misalignment due to rotation or traversal such as disconnection. Further, it is only necessary to select the optimum output of the light receiving element. Since this selection is the selection of the electric signal, it is possible to select it at a place distant from the device in operation.

[0014]

【Example】

 Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a diagram showing the optical system of the present embodiment. In the figure, 1 is a light source, 2 is a lens that collects the light of the light source 1, 3 is a half mirror that transmits and reflects the light, 4 is an object to be measured such as a web, 5 is a light receiving element, and 6 is a light receiving element. It is a supporting portion for fixing the light receiving element 5. The light receiving element 5 is installed at a position where the diffuse reflection light from the DUT 4 can be received and a position where the specular reflection light can be received. The output of these two light receiving elements is switched by a switch at a position not shown and either one is output.

Next, the operation will be described. Diffuse reflected light and specular reflected light from the moving DUT 4 are simultaneously received and detected by the respective light receiving elements 5. However, since the diffuse reflected light receiving element and the specular reflected light receiving element have different light receiving methods, Naturally, the state of the light reception signal also differs. When the DUT 4 is a paper that diffusely reflects, the output of the diffuse reflection light receiving element is selected. Also, in the case of aluminum film, film, or silver-based printing that is close to specular reflection, select the output of the specular reflection light receiving element. This selection may be switched by the operator according to the type of the DUT 4 with a switch.

As described above, since the output of the light receiving element is selected by switching the electric signal, it can be operated at a place distant from the device in operation, which is safe.

Further, since each light receiving element is fixed to the supporting portion 6, the light receiving angle does not change, and the displacement due to vibration does not occur. Also, since there are no moving parts, cutting of lead wires does not occur.

[0018]

[Effect of the device]

 As is clear from the above description, the present invention fixes the light receiving element at a plurality of reflected light guiding positions and selects and outputs the optimum light receiving element output according to the object to be measured. It is possible to prevent the occurrence of an inconvenient situation. Also, the selection of the output signal can be performed from a position remote from the device.

[Brief description of drawings]

FIG. 1 is a diagram showing an optical system according to an embodiment of the present invention.

FIG. 2 is a diagram showing a basic structure of a kasumi printing.

FIG. 3 is a diagram illustrating register marks.

FIG. 4 is a diagram showing a light receiving system of a conventional mark detection device.

[Explanation of symbols]

 1 light source 2 lens 3 half mirror 4 DUT 5 light receiving element 6 support

Claims (1)

Claims for utility model registration: 1. A mark position detecting device for irradiating a moving object to be measured having a mark at a predetermined position with light, detecting reflected light from the mark, and detecting the mark position. A mark position detection device characterized in that the reflected light is guided to a plurality of locations, and light receiving elements are provided at the plurality of locations respectively so that the output of the light receiving element located at a position according to the type of the object to be measured can be selected. ..