Full-process online intelligent quality detection method based on single printed product

Abstract

The invention discloses a full-process online intelligent quality detection method based on a single printed product, which comprises the following steps: forming a unique identification code on a single printed material, and printing through an offset printing process to obtain an offset printed product; the offset printing product is subjected to subsequent process treatment; quality detection is conducted on product patterns of all printing areas of the single-piece printing materials, and the single-piece printing materials where the suspected defects are located are marked as defective plates; taking out each defective product plate by a worker at the field detection station, manually rechecking the defective product, and making an obvious mark on the defective product by using an identification tool; and each small product area is cut off on the single printing material, and defective products which are detected to be unqualified are separated out through product on-line quality inspection equipment. According to the invention, quality detection is carried out on a large piece of product in advance, and an obvious mark which can be accurately identified by the product on-line quality detection equipment is made on the defective product, so that the defective product which is detected to be unqualified can be accurately separated out through the product on-line quality detection equipment.

Description

Technical Field

[0001] This invention belongs to the field of printing, and in particular relates to a full-process online intelligent quality inspection method for single-sheet printed products. Background Technology

[0002] Sheet-printed products refer to printed materials that undergo all printing and post-processing on a single sheet of printing material (mainly paper, but also including cardboard, plastic sheets, etc.), and are ultimately delivered and used as finished products in single-sheet form. Sheet-printed products are typically printed on large sheets of printing material and then cut into smaller finished products through a die-cutting process.

[0003] In current printing processes, quality inspection is generally carried out by sampling the finished products after die-cutting, with a sampling rate typically between 5% and 10%. However, sampling cannot guarantee the detection of all defective products. Therefore, when the product pass rate requirement is high, a full inspection is also conducted on the finished products. However, due to the small area and large quantity of finished products, a full inspection takes a long time.

[0004] Furthermore, the surface patterns created by processes such as hot stamping have strong reflective properties, frequently interfering with images captured by online product inspection equipment and leading to false detections. Additionally, minor flaws that do not affect product use are also detected and judged as defective products, resulting in low accuracy and a false detection rate exceeding 20%, sometimes even surpassing 30%. Therefore, many defective products identified as defective by online product inspection equipment are actually usable; to avoid waste, all defective products must be manually re-inspected, significantly reducing efficiency. Summary of the Invention

[0005] To address the shortcomings of the existing technology, the technical problem to be solved by the present invention is to provide a full-process online intelligent quality inspection method for single-sheet printed products.

[0006] To solve the above-mentioned technical problems, the present invention provides the following technical solution: A fully online intelligent quality inspection method for single-sheet printed products includes the following steps: S100. Divide a single sheet of printing material into multiple small product areas and assign a location number to each small product area. S200: A unique identification code is formed in the blank area of ​​a single sheet of printing material, and a predetermined pattern is printed on each small product area of ​​each single sheet of printing material through offset printing process to obtain an offset printed product. S300: Perform post-processing on offset printed products to form the required product pattern in each printing area. S400. Perform quality inspection on the product patterns in each printing area of ​​a single sheet of printing material. If the product patterns meet the quality inspection requirements, they are judged as qualified products; otherwise, they are judged as defective products. The single sheet of printing material where the suspected defects are located is marked as a defective board. The identification code of the defective board and the location number of the defective products are compiled into a re-inspection product list and sent to the on-site inspection station before die-cutting. S500: On-site inspection staff take out each defective board according to the re-inspection product list and manually review the defective products. If the review determines that the defective product meets the product use requirements, it is modified into a qualified product; otherwise, a clear mark is made on the defective product using a marking tool. S600: The die-cutting mechanism cuts out small product areas from a single sheet of printing material. Each small product area is a printed finished product. The online product inspection equipment separates out the defective products that are found to be unqualified.

[0007] Furthermore, in step S100, the small product areas are arranged in an array on a single sheet of printing material, and the position number of the small product areas includes row number and column number.

[0008] Furthermore, the single-sheet printing material is a large sheet of paper.

[0009] Furthermore, in step S200, the identification coding is performed by sequential coding according to the printing order of a single sheet of printing material.

[0010] Furthermore, after performing step S200, the following steps are also performed: S210. Perform online quality inspection on the obtained offset printing products using offset printing quality inspection equipment, and remove defective offset printing products. In step S300, defective offset printing products are processed separately in subsequent processes.

[0011] Furthermore, after performing step S210, the following steps are also performed: S220. Detect the number of small product areas involved in defects in offset printing products. When the number exceeds a preset threshold, the offset printing product is rejected as waste.

[0012] Furthermore, in step S300, the subsequent process includes one or more of hot stamping, embossing, screen printing, and single-relief printing.

[0013] Furthermore, a quality control center is established to inspect and track product quality; step S400 includes the following sub-steps: S410. Use large-scale online inspection equipment to inspect the quality of the product patterns in each printing area of ​​the single sheet of printing material after the completion of the next process, and send the images of the questionable products to the quality control center. S420. Quality control center staff manually judge whether each questionable product meets the usage requirements by using images on the display device, and mark questionable products that do not meet the product usage requirements as defective products, and mark the single sheet of printing material with defective products as substandard board. S430. The quality control center compiles the identification codes of the defective boards and the location numbers of the defective products after manual judgment into a re-inspection product list and sends it to the on-site inspection station before die-cutting.

[0014] Furthermore, the quality control center is also used to store relevant data on questionable products to facilitate product traceability.

[0015] Furthermore, in step S600, the individual printing materials that are not marked as defective are uniformly die-cut, and the die-cut printed products are exempt from inspection. Each sheet of printing material marked as defective is die-cut separately, and a full inspection is carried out on the die-cut printed products. Defective products that fail the inspection are separated by online product inspection equipment.

[0016] In this invention, a quality control center is established to conduct pre-production quality checks on large sheets of products. Defective products are clearly marked so that online inspection equipment can accurately identify them. This allows for the precise separation of defective products by the online inspection equipment, significantly improving quality inspection efficiency and enabling full-process management of the production process. By inspecting offset-printed products, defective sheets can be pre-sorted, reducing the workload of subsequently locating them and further enhancing quality inspection efficiency. Attached Figure Description

[0017] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a flowchart of an embodiment of the online intelligent quality inspection method for the entire process of single-sheet printed products according to the present invention.

[0018] Figure 2 This is a flowchart for quality inspection of product patterns on a single sheet of printing material. Detailed Implementation

[0019] The following specific examples illustrate the implementation of the present invention. The illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0020] Please see Figure 1 , Figure 1 This is a flowchart illustrating an embodiment of the online intelligent quality inspection method for the entire process of single-sheet printed products according to the present invention. The online intelligent quality inspection method for single-sheet printed products in this embodiment includes the following steps: S100. Divide the single sheet of printing material into multiple small product areas, and assign a position number to each small product area. In this embodiment, the small product areas are arranged in an array on the single sheet of printing material, and the position number of the small product area includes a row number and a column number. The single sheet of printing material is generally a large sheet of paper. A large sheet is usually also called a "full sheet" or "uncut sheet," which refers to the largest standard sheet of paper used by the printing press. In sheet printing, in order to pursue the highest efficiency, multiple pages or products are usually printed on this largest sheet of paper at once, and then they are separated into final small-sized finished products through subsequent cutting processes.

[0021] The number of small product areas is determined by the actual size of the finished product. Taking cigarette boxes as an example, for a small box containing 20 cigarettes, a large sheet of printing material can be divided into dozens of small product areas. The finished product formed by one small product area can be used to glue together to form a small cigarette box. For a medium-sized box containing 10 packs of cigarettes, a large sheet of printing material can be divided into about a dozen small product areas. For a large box containing multiple cartons of cigarettes, a large sheet of printing material will be divided into even fewer small product areas.

[0022] S200. A unique identification code is formed in the blank area of ​​each sheet of printing material (i.e., the area outside the individual product areas, such as the upper left corner of the sheet) to facilitate subsequent tracking in case of defects; and a predetermined pattern is printed on each individual product area of ​​each sheet of printing material using offset printing technology to obtain the offset printed product. The identification code can be formed on the sheet of printing material first using processes such as laser marking, and then offset printing is performed. To facilitate subsequent retrieval of individual sheets of printing material, the identification code is generally sequentially coded according to the printing order of the individual sheets.

[0023] To achieve full-process management of printed products and further improve quality inspection efficiency, after completing step S200, the following steps are also performed: S210. Online quality inspection of the obtained offset printing products is performed using offset printing quality inspection equipment, and defective offset printing products are removed. The inspection method involves acquiring images of the offset printing products and comparing them with pre-stored standard images of offset printing products. The presence of defects is determined based on the comparison results. Upon detecting defective offset printing products, the quality inspection equipment will alarm to alert staff and display the relevant defects and the identification code of the individual printing material on the display device. Staff can check the identification code after hearing the alarm and quickly locate (generally within one minute) the defective offset printing products for isolation. Since these offset printing products will essentially be judged as substandard sheets in subsequent inspections, separate processing can improve the efficiency of subsequent inspections.

[0024] Since large defect areas in offset printing products render further processing pointless, the following steps can be performed after completing step S210: S220. Detect the number of small product areas involved in defects in offset printing products. When the number exceeds the preset threshold, the offset printing product is considered to have no value for further processing and is rejected as waste, and will not be processed in subsequent processes.

[0025] S300: Post-processing of offset printed products, forming the desired product pattern in each printing area. As living standards improve, people have higher aesthetic demands, requiring printed products to be more beautiful and have a better texture. Post-processing is necessary after offset printing to enhance the quality of the printed products. Common post-processing techniques include hot stamping, embossing, screen printing, and gravure printing.

[0026] In this step, the qualified offset printed products will first undergo post-processing, and then the defective offset printed products will undergo post-processing separately. Since the defective offset printed products will generally be identified as questionable products after post-processing, the pattern in the defective area will be judged as problematic. Therefore, in the subsequent S500 step, this portion of the single-sheet printing material can be directly removed without searching through a large number of single-sheet printing materials. This effectively pre-screens a portion of the questionable products, thus reducing the workload when searching for the single-sheet printing material containing the questionable products.

[0027] S400. Perform quality inspection on the product patterns in each printing area of ​​a single sheet of printing material. If the product patterns meet the quality inspection requirements, they are judged as qualified products; otherwise, they are judged as defective products. The single sheet of printing material where the suspected defects are located is marked as a defective board. The identification code of the defective board and the location number of the defective products are compiled into a re-inspection product list and sent to the on-site inspection station before die-cutting.

[0028] In this embodiment, a quality control center is added to inspect and track product quality. The quality control center can interact with offset printing quality inspection equipment, large-sheet online inspection equipment, and product online quality inspection equipment to collect quality data, such as images of questionable products, the identification code of the printing material on the corresponding sheet, and the location number of the corresponding small-sheet product area, achieving full-process online data collection. Please refer to [link to relevant documentation]. Figure 2 The S400 step may include the following sub-steps: S410. The product patterns in each printed area of ​​the single sheet of printing material after the subsequent process are inspected using a large-sheet online inspection device, and images of problematic products are sent to the quality control center. The inspection method involves acquiring images of the single sheet of printing material and comparing them with pre-stored standard images of the large sheet of finished products. Problematic products are those whose patterns may have defects, i.e., products that are not qualified. Alternatively, images of the defective areas in the problematic products can be captured, enlarged, and sent to the quality control center for assessment by its staff.

[0029] S420. Quality control center staff manually assess whether questionable products meet usage requirements via images on the display device. Questionable products that meet usage requirements are still classified as qualified. For example, when a questionable product has only minor flaws or defects located at the adhesive area that do not affect usability, it can be judged as qualified based on experience to avoid system misjudgments and save production costs. Products that may have defects (i.e., not meeting usage requirements) are marked as defective products. These defective products are associated with the identification code of the corresponding sheet of printing material, and the sheet containing the defective product is marked as a substandard sheet for processing in subsequent processes.

[0030] S430. The quality control center compiles the identification codes of the defective boards and the location numbers of the defective products after manual inspection into a re-inspection product list and sends it to the on-site inspection station before die-cutting. The on-site inspection station is generally located before the die-cutting equipment. The first-level directory of the re-inspection product list is generally the identification code of the defective board, and the second-level directory is generally the location number of each defective product in each board. This allows the on-site inspection staff to first find the defective board according to the identification code and then locate the defective product according to the location number. The quality control center also stores relevant data of the questionable products (such as product images) to facilitate product traceability.

[0031] In S500, on-site inspection staff retrieve each defective sheet from the re-inspection product list and manually verify the defective products. Since the number of individual printing sheets is far less than the number of finished printed sheets after die-cutting, the search efficiency is greatly improved. Furthermore, each printing sheet has a sequentially numbered identification code, which can be used to determine the approximate location of the defective sheets, making it easy to find them from a stack of sheets. In addition, the online quality inspection of offset printing products has already performed a sorting process, isolating some defective sheets and reducing the number of defective sheets that need to be searched in this step (defective offset printing products are processed separately in subsequent processes; these processed products are all defective sheets and do not need to be searched from qualified products).

[0032] Subsequently, if the review determines that the defective product meets the product usage requirements, it is modified into a qualified product; otherwise, a clear mark is made on the defective product using a marking tool. This clear mark is a mark that the online inspection device on the die-cutting equipment can accurately identify as unqualified, for example, by drawing an "X" with a marker. Therefore, subsequent quality inspections only need to check for the presence of this clear mark on the product.

[0033] S600: The die-cutting mechanism cuts out individual product areas from a single sheet of printing material. Each small product area is a printed finished product. Defective products that fail the inspection are separated by online product inspection equipment. In this step, single sheets of printing material that are not marked as defective (i.e., single sheets of printing material containing only qualified products) can be die-cut together, and the die-cut printed finished products are exempt from inspection to improve production efficiency.

[0034] Individual sheets of printing material marked as defective are die-cut separately, and a full inspection is conducted on the die-cut printed products. Defective products are separated using online quality control equipment. Since defective products have easily identifiable markings, the detection precision of the online quality control equipment can be lowered before implementing full inspection to avoid misidentifying qualified products as defective. Because defective products are clearly marked, they will still be accurately detected even after lowering the detection precision.

[0035] In this embodiment, by setting up a quality control center to conduct pre-production quality inspections on large sheets of products and marking defective products with clear markings that can be accurately identified by online product inspection equipment, defective products can be accurately separated using the online inspection equipment, greatly improving quality inspection efficiency and enabling full-process management of the production process. By inspecting offset printing products, defective boards can be pre-diverted, reducing the workload of subsequently locating defective boards and further improving quality inspection efficiency.

[0036] The above embodiments merely illustrate preferred implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the protection scope of the present invention. Therefore, the protection scope of this invention should be determined by the appended claims.

Claims

1. A method for end-to-end online intelligent quality inspection of sheet-fed printed products, characterized in that, Includes the following steps: S100. Divide a single sheet of printing material into multiple small product areas and assign a location number to each small product area. S200: A unique identification code is formed in the blank area of ​​a single sheet of printing material, and a predetermined pattern is printed on each small product area of ​​each single sheet of printing material through offset printing process to obtain an offset printed product. S300: Perform post-processing on offset printed products to form the required product pattern in each printing area. S400. Perform quality inspection on the product patterns in each printing area of ​​a single sheet of printing material. If the product patterns meet the quality inspection requirements, they are judged as qualified products; otherwise, they are judged as defective products. The single sheet of printing material where the suspected defects are located is marked as a defective board. The identification code of the defective board and the location number of the defective products are compiled into a re-inspection product list and sent to the on-site inspection station before die-cutting. S500: On-site inspection staff take out each defective board according to the re-inspection product list and manually review the defective products. If the review determines that the defective product meets the product use requirements, it is modified into a qualified product; otherwise, a clear mark is made on the defective product using a marking tool. S600: The die-cutting mechanism cuts out small product areas from a single sheet of printing material. Each small product area is a printed finished product. The online product inspection equipment separates out the defective products that are found to be unqualified.

2. The online intelligent quality inspection method for the entire process of single-sheet printed products as described in claim 1, characterized in that: In step S100, the small product areas are arranged in an array on a single sheet of printing material, and the position number of the small product areas includes row number and column number.

3. The online intelligent quality inspection method for the entire process of single-sheet printed products as described in claim 1, characterized in that: The single-sheet printing material is a large sheet of paper.

4. The online intelligent quality inspection method for the entire process of single-sheet printed products as described in claim 1, characterized in that: In step S200, the identification coding is performed by sequential coding according to the printing order of a single sheet of printing material.

5. The online intelligent quality inspection method for the entire process of single-sheet printed products as described in claim 1, characterized in that, After completing step S200, the following steps are also performed: S210. Perform online quality inspection on the obtained offset printing products using offset printing quality inspection equipment, and remove defective offset printing products. In step S300, defective offset printing products are processed separately in subsequent processes.

6. The online intelligent quality inspection method for the entire process of single-sheet printed products as described in claim 5, characterized in that, After performing step S210, the following steps are also performed: S220. Detect the number of small product areas involved in defects in offset printing products. When the number exceeds a preset threshold, the offset printing product is rejected as waste.

7. The online intelligent quality inspection method for the entire process of single-sheet printed products as described in claim 1, characterized in that, In step S300, the subsequent process includes one or more of hot stamping, embossing, screen printing, and single-recessed printing.

8. The online intelligent quality inspection method for the entire process of single-sheet printed products as described in any one of claims 1 to 7, characterized in that: A quality control center is set up to inspect and track product quality; step S400 includes the following sub-steps: S410. Use large-scale online inspection equipment to inspect the quality of the product patterns in each printing area of ​​the single sheet of printing material after the completion of the next process, and send the images of the questionable products to the quality control center. S420. Quality control center staff manually judge whether each questionable product meets the usage requirements by using images on the display device, and mark questionable products that do not meet the product usage requirements as defective products, and mark the single sheet of printing material with defective products as substandard board. S430. The quality control center compiles the identification codes of the defective boards and the location numbers of the defective products after manual judgment into a re-inspection product list and sends it to the on-site inspection station before die-cutting.

9. The online intelligent quality inspection method for the entire process of single-sheet printed products as described in claim 8, characterized in that: The quality control center is also used to store relevant data on questionable products to facilitate product traceability.

10. The online intelligent quality inspection method for the entire process of single-sheet printed products as described in any one of claims 1 to 7, characterized in that: In step S600, the single sheets of printing material that are not marked as defective are uniformly die-cut, and the die-cut printed products are exempt from inspection. Each sheet of printing material marked as defective is die-cut separately, and a full inspection is carried out on the die-cut printed products. Defective products that fail the inspection are separated by online product inspection equipment.

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