Causes Of Paper Printing Distortion
During the printing process, the paper undergoes certain deformation due to printing pressure and peeling tension. After the paper with large plastic deformation leaves the embossing area, the deformation cannot be recovered, resulting in large overprinting errors.
1. Printing pressure and Printing distortion
Paper is a material with plastic deformation, and the plastic deformation characteristics of different papers are not the same.
Under the action of greater printing pressure, the width and the length of the trailing corners of the paper with large plastic deformation will slightly expand, resulting in inaccurate registration. Especially in the trailing part of the paper is more serious.
The greater the printing pressure, the more obvious the deformation of the paper.
Therefore, when printing the same batch of products, the pressure of each color Printing Distortion plate should be as consistent as possible, but sometimes the pressure should be adjusted according to the specific situation.
- The deformation of the paper is closely related to the thread of the paper. Taking into account the general offset press, the overprint error caused by the deformation of the paper under the printing pressure is more difficult to adjust in the axial direction than in the radial direction.
- Therefore, when printing, single sheet The paper should be as parallel as possible to the longitudinal direction of the paper and the axis of the roller, and for the same batch of products, the direction of the filaments of the printing paper must be the same to ensure the accuracy of overprinting. Never allow the same batch of products to be printed with different filaments of paper.
- Due to the fan-shaped deformation of the paper under the effect of printing pressure, images that require high overprinting accuracy or parts that are important to the theme should be arranged near the mouth during pre-press processing and plate making. Because the paper deformation near the gripper is small during printing, it is easy to overprint accurately.
2. Paper peeling tension and Printing distortion
- The paper after Printing Distortion in the embossing area is gripped by the grippers of the cylinder, forcing it to separate from the blanket, and the ink on the Printing Distortion plate acts as a medium to stick the printed sheet on the surface of the blanket with strong adhesion.
- At this time, the fibrous structure on the printed sheet is affected by forces in two directions, one is the downward gripping force of the grippers on the paper, and the other is the upward adhesion of the ink to the paper. The directions of these two forces are opposite.
- When the printed sheet is peeled from the blanket, the trailing tip of the paper is easily curled and does not fit with the impression cylinder, forming a bending angle, which is called the peeling angle.
- If the adhesion of the ink is large, the longer the printed sheet will be peeled and pulled down by the grippers, the larger the peeling angle, the greater the peeling tension and the peeling and stretching deformation of the paper will increase, and the paper will be stretched along the radial direction of the cylinder, and overprint Decrease in accuracy.
If the gripper of the impression cylinder has sufficient gripping force:
- The nature of the paper. Paper with large plastic deformation has large peeling and stretching deformation, and vice versa.
- The printing pressure and the time for the roller to impress each other. The greater the printing pressure, the longer the imprinting time, the longer the contact time between the paper and the ink on the blanket, and the greater the peeling and stretching deformation.
- The ink-receiving area on the surface of the paper. The larger the ink area, the thicker the ink layer, and the greater the peeling and stretching deformation.
- The viscosity and adhesion of the ink. The greater the viscosity and adhesion of the ink, the greater the peeling and stretching deformation, and vice versa.
- Bar code Printing distortion quality management, especially bar code Printing distortion qualification certification, has greatly improved the bar code printing quality.
- However, to further grasp the key points of barcode quality management and improve the efficiency and effectiveness of barcode printing quality management is still a topic that barcode printing companies and barcode quality management related staff need to continue to pay attention to and discuss.
- Today, the editor of China Paper Network searches for related packaging and the like, and makes preliminary exploration and analysis of bar code Printing distortion quality management and bar code printing qualification certification.
1. Barcode is Printing distortioncentered on quality
- Bar code quality is one of the many quality factors of printing companies: an important part. In some cases, unqualified barcode quality will lead to overall barcode Printing distortion and quality control
- Unqualified Printing distortion quality has even caused tens of millions of printed packaging to be scrapped, causing economic losses and reputational losses to printing companies. Barcode printing quality management should be quality-centric, which is mainly reflected in the following two points.
2. Barcode quality awareness
- The first is the bar code quality awareness of business leaders. The leaders of Printing distortion companies are the leaders and main executors of bar code quality management.
- Therefore, the bar code quality awareness of the leaders of Printing distortion enterprises is an important factor to measure the quality of bar code printing.
- The second is the awareness of all employees on bar code quality work. Including the bar code quality management work must meet the requirements of the “Commodity Barcode Management Measures” promulgated by the General Administration of Quality Supervision,
- Inspection and Quarantine and the “Implementation Rules for the Certification of Product Barcode Printing Qualifications”, and the quality of product barcode printing must meet the requirements of relevant national standards.
3. Decomposition and implementation of quality objectives and quality policies
- Bar code printing companies should decompose the quality policy and quality objectives into business contact, design and plate making, printing materials, printing technology, quality inspection, etc.,
- determine bar code quality control points, formulate corresponding quality management systems, and load them into bar code printing quality In the manual, and clearly stated in the corresponding management department.
- The resources (including human, financial, and material) required for bar code printing quality management work should be optimized.
2. Effectively implement relevant national standards and regulatory documents
- In order to ensure the quality of barcodes, the country has promulgated and implemented a series of national standards.
- including: GB12904-2003 “Barcodes for Commodities”, GB/T14257-2002 “Barcode Printing Positions for Commodities”, and GB/T18348-2001 “Quality Inspection of Barcode Symbols for Commodity Printing” “, GB/T14258-2003 “Quality Inspection of Tire Ring Numbers” and other national standards, “Commodity Barcode Management Measures”, “Commodity Barcode Printing Qualifications Implementation Measures” and other regulatory documents. Barcode printing companies should pay attention to the study and implementation of these national standards and regulatory documents, send people to participate in the training and learning organized by relevant institutions, compile learning materials according to the actual situation of the company, and distribute them to relevant departments to organize and learn.
- Fully familiar with bar code quality requirements and related technical parameters, such as magnification factor, left and right blank area size, bar color matching, decoding degree, bar code uniqueness, symbol level, etc., so that standards and technical regulations can be implemented.
4.Three, barcode printing quality management must form a system
- Barcode printing quality management is a systematic project, and printing companies must establish a barcode quality assurance system.
- In the form of a barcode quality manual signed by the top leaders of the enterprise, it is promulgated and implemented, so that many factors affecting the quality of barcodes in each process and management link are under control, and the linkage and matching of barcode quality management links in each production process are ensured.
- Avoid local bar codes that work well, but the overall quality is poor, or the overall quality is good, but there are major omissions in the local area.
5. Ensure the effectiveness and long-term nature of bar code Printing distortion quality management
1. Strengthen system construction
- To ensure the effectiveness and long-term nature of the bar code Printing distortion quality management work, a strong system must be used as a guarantee.
- Enterprises should establish and improve barcode verification systems, barcode design review systems, barcode offset film management systems, and barcode quality inspection systems, and continue to address new problems in accordance with the requirements of relevant state departments and the development of barcode technology, as well as new problems discovered in the practice of barcode Printing distortion.
- Complete. Business leaders should take the lead in complying with the system. No one can violate the system for any reason, so that the implementation of the system is not shifted by human will, and rewards and punishments should be clearly defined.
2. Ensure the timeliness of national bar code standards and regulatory documents. National bar code standards.
- such as GB12904-2003 “Barcodes for Commodities”, GB/T14257-2002 “Printing distortion of Commodity Barcodes” and regulatory documents.
- such as “Management Measures for Commodity Barcodes” are all implemented If it is re-promulgated and implemented after major revisions, printing companies should quickly adjust the technical and management content of relevant corporate documents in accordance with the latest bar code national standards and regulatory documents to adapt to the new technical and management requirements.
3. To ensure the continuity and integrity of bar code quality records, printing companies should follow the four systems of bar code management,
- namely the bar code verification system (mainly records the company name, address, manufacturer identification code, and the validity period of the bar code certificate), and the bar code design review system ( It mainly records the size of the barcode, the color matching of the barcode, the printing position of the barcode and the product item code), the management system of the barcode film offset (mainly records the film name, quantity, barcode code, film integrity, storage location and serial number, etc.)
- and the barcode inspection system ( Mainly record the left and right blank area size, magnification factor, bar height, printing position, bar color, uniqueness of code, quality level, inspection time, inspection location, inspector, inspection conclusion, etc.)
- for detailed registration and recording. These records must It is continuous and complete without interruption or omission. Only in this way can the continuity and effectiveness of the bar code printing quality management work be maintained.