Laser beam performance test method for paper surface

Abstract

The present invention discloses a method for detecting the performance of laser beams on the surface of paper. The method comprises the following steps: producing two extra-long barcodes at the position of the barcode on the cigarette label of the laser beam paper strip, and extending the length from the printing edge to the end of the printing plate; using two color groups to print the barcode in white and one color group to print the barcode in black; setting a position 50 mm from the edge of the paper at the edge as the starting point, and performing a light beam cycle every 49 mm from this position toward the end of the printing plate; detecting the barcode once every 1 mm along the barcode direction using a desktop barcode detector, and recording the barcode defect value; and continuously selecting multiple light beam cycles on the same sheet of paper; and continuously measuring several sheets of laser beam paper. The present invention has the following beneficial effects: determining the cause of the abnormal barcode defect in a specific area of ​​the laser beam paper by detection, and thereby avoiding the position of the paper with high defectivity, thereby solving the problem of the influence of the laser beam at a specific position on the laser beam paper on the barcode defectivity.

Description

Technical Field

[0001] The invention relates to the technical field of cigarette packaging box bar code printing, in particular to a method for detecting laser beam performance on the surface of paper. Background Art

[0002] In the field of cigarette packaging printing, major cigarette factories have very strict requirements on the barcodes of cigarette package label paper. The grade must be above level 3, that is, the seven indicators that determine the barcode grade must be above level 3. Moreover, the barcode grade is a veto item for the quality of cigarette package label paper products. If the barcode grade is unqualified, all products will be scrapped.

[0003] To ensure mass production quality, cigarette packaging printing companies have been forced to raise internal control standards for barcode grades. For white cardboard cigarette packaging, achieving a barcode grade of 3 is relatively easy, as only the black barcode needs to be controlled. However, achieving a barcode grade of 3 for laser cardboard cigarette packaging is more difficult, especially for offset printing, which requires both controlling the printing quality of the black barcode and strictly controlling the printing of the white barcode ink. Offset white ink has a thinner layer, and a single print provides insufficient coverage of the laser paper's light beam, making it very easy for the bottom to show through, resulting in excessive barcode defects. To achieve barcode standards, multiple color combinations are required to print the white barcode. Therefore, testing the surface light beam performance of laser cardboard is particularly important.

[0004] Patent document CN112008999A discloses an environmentally friendly laser beam frame paper, which is made by coating a uniform layer of glue on a PET film and then placing it in a closed mold cavity. A nickel plate engraved with a beam is used to laser process the product, thereby engraving a laser beam on the PET film. The PET film after the molding process is vacuum-aluminized to obtain a PET laser beam transfer film. Before the PET laser beam transfer film is coated, a spare water-based glue is prepared and then placed in a laminating machine together with the base paper for bonding and lamination. Finally, the composite is placed in a rewinding machine and rewound. The winding machine separates the base paper from the PET laser beam transfer film, thereby obtaining laser beam paper. When the semi-finished product after engraving cools to below 35°C, it is placed on a cutting machine and cut horizontally and vertically according to the frame size of the produced frame paper to obtain laser beam frame paper. The water-based glue used in the above production process is more environmentally friendly than traditional oil-based glue, and its ingredients are all non-toxic substances, which effectively improves the overall environmental performance of the frame paper. The laser beam stripes on the outer surface of the paper are clear and have an excellent gloss, which is very aesthetically pleasing. However, the patent does not address how to detect the surface beam performance of the laser beam paper.

[0005] Patent document CN213398177U discloses a device for detecting registration marks on laser beam paper produced by a roll-to-roll multi-color gravure printing press. By cleverly combining a specific polarization filter lens with a photoelectric detection sensor, the device can effectively detect registration marks on laser beam paper produced by a roll-to-roll multi-color gravure printing press, ensuring accurate registration and printing of laser beam paper. However, the document does not disclose the specific parameters and performance of laser beam paper, nor does it disclose how to mitigate surface performance defects of laser beam paper. Summary of the Invention

[0006] The purpose of the present invention is to overcome the above technical defects and propose a method for detecting the performance of laser beams on the surface of paper, which can detect the regular influence of the position of the laser beam on the defects of the barcode.

[0007] The technical solution adopted by the present invention to achieve its technical purpose is: a method for detecting the performance of a laser beam on the surface of paper, comprising the following steps:

[0008] S1: Create two extra-long barcodes at the location of the barcode on the laser beam paper strip and run from the printing edge to the end of the plate;

[0009] S2: Use two color groups to print the barcode in white, and one color group to print the barcode in black;

[0010] S3: Set the position 50mm away from the paper edge at the grip as the starting point, and from this position towards the end of the plate, every 49mm is a light beam cycle;

[0011] S4: Use a desktop barcode detector to inspect the barcode every 1 mm along the barcode direction, record the barcode defect value, and draw a graph of the inspection position and barcode defect data;

[0012] S5: Select nine consecutive light beam cycles on the same paper;

[0013] S6: Draw a line graph showing the relationship between the defectivity and the detection position in each light beam cycle;

[0014] S6: Continuously measure several sheets of laser beam paper.

[0015] Preferably, the width of each light zone in the direction perpendicular to the light column is 49 mm.

[0016] Preferably, in step S3, the measurement starting point is the center point of the second light beam at the gripping edge.

[0017] The present invention has the beneficial effect of using the above-mentioned detection method to generate a graph showing the detection position and barcode defectivity. This method can determine that abnormal barcode defectivity in a specific area of ​​laser-beamed paper is caused by the precise coincidence of the reflection angle of the laser beam in that specific area of ​​the paper with the detection angle of the barcode reader. By controlling the position of the laser beam and the distribution of barcode positions on the printed page, all barcodes on the page are positioned away from areas of paper with high defectivity, thus resolving the issue of the laser beam's influence on barcode defectivity at specific locations on the paper. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 Barcode printing effect diagram:

[0019] Figure 2 Detect barcode position map for barcode detector;

[0020] Figure 3 To record the barcode defect value;

[0021] Figure 4 This is a graph showing the barcode defectivity at different locations during nine consecutive light beam cycles.

[0022] Figure 5 Line charts are drawn for nine data sets. DETAILED DESCRIPTION

[0023] The present invention will be further described below with reference to the accompanying drawings:

[0024] Example 1

[0025] like Figure 1-5 As shown: The method for detecting the performance of laser beam on the surface of paper includes the following steps:

[0026] S1: Create two extra-long barcodes at the location of the barcode on the laser beam paper strip and run from the printing edge to the end of the plate;

[0027] S2: Use two color groups to print the barcode in white, and one color group to print the barcode in black;

[0028] S3: Set the position 50mm away from the paper edge at the grip as the starting point, and from this position towards the end of the plate, every 49mm is a light beam cycle;

[0029] S4: Use a desktop barcode detector to inspect the barcode every 1 mm along the barcode direction, record the barcode defect value, and draw a graph of the inspection position and barcode defect data;

[0030] S5: Select nine consecutive light beam cycles on the same paper;

[0031] S6: Draw a line graph showing the relationship between the defectivity and the detection position in each light beam cycle;

[0032] S6: Continuously measure several sheets of laser beam paper.

[0033] The working principle and working process of the present invention are as follows:

[0034] At the position of the barcode on the cigarette label, two extra-long barcodes are made, which run from the printing edge to the end of the plate, and are completely in accordance with the offset printing process of mass production. The white barcode is printed in two color groups, and the black barcode is printed in one color group. The printing effect is as follows: Figure 1 shown.

[0035] Use a desktop barcode detector to detect the barcode every 1 mm along the barcode direction and record the barcode defect value. Figure 2 、 Figure 3 shown.

[0036] Since the width of each laser beam area perpendicular to the beam direction is 49mm during the production of laser beam paper, the starting point is 50mm from the edge of the paper at the gripper, that is, the center point of the second beam at the gripper. From this position to the end of the paper, every 49mm is a beam cycle. Scan once every millimeter and select nine beam cycles on the same paper. Record the barcode defect value, the data is as follows Figure 4 shown.

[0037] In the barcode defect value, the dark part is the defect standard data, and the light part is the data that exceeds the standard. Figure 4 They are similar, so they are not listed one by one.

[0038] Draw line graphs for the nine data groups, such as Figure 5 shown.

[0039] According to the data analysis in the chart, within each light beam cycle, the defect value of the barcode begins to rise significantly from the 15mm position, reaches a peak at the 22-24mm position, and then begins to decline. At the 30mm position, the defect data returns to normal.

[0040] Data analysis revealed that the beams exceeding the internal control value of 15 mm were concentrated between 17 and 25 mm, with a width of approximately 8 mm. The pattern was clear and distinct, and they strictly followed the 49 mm interval period of the beams.

[0041] Based on the aforementioned laser beam performance testing method for paper surfaces, it's concluded that abnormal barcode defectivity in specific areas of laser beam paper occurs because the reflection angle of the laser beam in that specific area of ​​the paper coincides with the barcode reader's detection angle. When the barcode reader's laser head detects this area, the paper's beam reflects strongly, making it difficult for the white ink to fully mask the reflected light, resulting in an extremely high barcode defectivity reading.

[0042] Therefore, in order to solve the problem of the laser beam at a specific position on the paper affecting the barcode defect rate, it is necessary to control the position of the laser beam on the paper and the distribution of the barcode positions on the printing plate so that the positions of all barcodes on the plate avoid the positions of the paper with high defect rates.

[0043] During production, the laser beam characteristics of the paper and the barcode position within the cigarette pack can be used to determine the number of panels, orientation, and clamping blades for the cigarette pack, effectively avoiding areas with high laser beam defects. Laser beam position inspection is performed after the sheets are cut and stored.

[0044] Based on the laser beam performance at specific locations on the paper, we avoid locations with high defect rates to ensure that barcode defect levels meet the required standards. Furthermore, for very bright laser beam paper, offset printing with two color groups of white ink can achieve the required barcode grade. For papers with weaker laser beam performance, such as medium paper, offset printing with a single color group of white ink can meet the required barcode grade.

Claims

1. A method for detecting the performance of laser beams on paper surfaces, characterized in that: The following steps are involved: S1: Create two extra-long barcodes at the location of the barcode on the laser beam paper strip and run from the printing edge to the end of the plate; S2: Use two color groups to print the barcode in white, and one color group to print the barcode in black; S3: Set the position 50mm away from the paper edge at the grip as the starting point, and from this position towards the end of the plate, every 49mm is a light beam cycle; S4: Use a desktop barcode detector to inspect the barcode every 1 mm along the barcode direction, record the barcode defect value, and draw a graph of the inspection position and barcode defect data; S5: Select nine consecutive light beam cycles on the same paper; S6: Draw a line graph showing the relationship between the defectivity and the detection position in each light beam cycle; S6: Continuously measure several sheets of laser beam paper.

2. The method for detecting laser beam performance on paper surface according to claim 1, characterized in that: The width of each light zone perpendicular to the light column is 49mm.

3. The method for detecting laser beam performance on paper surface according to claim 1, characterized in that: In step S3, the measurement starting point is the center point of the second light beam at the gripping edge.

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