Quality Control of Color Newspaper Printing

Editor's note: China’s newspaper publishing has achieved great development in recent years. The improvement of people’s living standards has led to the domestic publication of newspapers. Major newspapers have introduced color newspaper printing production lines, which has resulted in a larger newspaper printing technology in China. As a result, the total number of single-period editions of newspapers, the proportion of color newspapers, and the quality of printing have all greatly improved. But at the same time, although our hardware and equipment have risen by a certain step, and our software system has not yet kept pace, the technical support and quality management of color newspaper printing have been placed in front of us without delay.

As we all know, technology is the cornerstone of quality. Print quality management is also the technical control of the printing process. For a printing factory, to improve the printing quality of newspapers, the management department should understand all the factors that affect the printing quality of the overall newspaper, so that these factors are strictly controlled technically to form a set of open quality control systems, and The actual production process is constantly improved and supplemented.

Establishment of quality control system

The management of printing quality should establish a general concept, establish an effective quality control system, and all production departments should plan and manage in a unified manner and work together around the quality control system. The standardization and dataization of the process is the core of the quality control system. In general, newspaper printing includes three processes: prepress, plate making and printing. When we establish a quality control system, the specification and dataization of these three process flows are the basis, and the inspection and control of printed raw materials should also be included. The following outlines the establishment of a print quality control system.

1. Prepress process quality control

For the prepress process, because it is the beginning of the entire printing process, directly affecting the subsequent processes, controlling the quality of the prepress process is our top priority.

The quality control of the prepress process includes the standardization of the manuscript, the standardization of the scanning process, the standardization and dataization of the image processing, and the standardization of the photosetting process.

The standardization of manuscripts was proposed to the editorial department and the advertising department, requiring the provision of high quality manuscripts as much as possible; the standardization of the scanning process refers to scanning parameters such as resolution, color mode, proportion, and equal quality control; standardization of image processing and data Including the level of correction and color correction of the data control; phototypesetting process of standardization is the film's on-site maximum density, fog, linear quality control.

2. Quality control of plate making process

The process of plate making is a process that connects the up and down, and the quality management concept of the plate making process is stable. The quality control of the platemaking process can be controlled by quality control means such as printing quality control strips, developing liquid conductivity meter and PH meter, and special PS version dot tester.

The basic point of quality control of the platemaking process is to control the exposure intensity and time of the PS plate, to measure the conductivity and PH value of the developing and fixing syrup, and to measure the dot enlargement and dot reproducibility of the PS plate.

3, the quality control of the printing process

The core of the quality control of newspaper printing process is "two levels and one uniform." The two levels are the gray balance control and the ink balance control. Uniformly means the evenness of the ink.

To get the correct gray balance, you need to understand the characteristics of the ink and paper used. The general principle for determining the proportion of three-color dots is: Since newsprint is yellowish, yellow dots are the smallest, magenta is larger than yellow, and blue dots are the largest. As for how much the proportion of three-color dot network is determined in the end, it is necessary to summarize the data of the gray balance point according to the actual situation of each printing factory according to the actual situation and environment of each printing factory. After determining the ratio of the dots of each color, an ash balance control bar is made, and a black control zone is also included to determine a standard gray axis to be brought to the newspaper layout. During the printing process, the printing shop adopts the gray balance control bar as the standard to adjust the ink volume of the three-color ink, so that the gray balance control bar presents a visual neutral gray, and is visually consistent with the standard gray axis, and can be controlled. Colors in the printing process of color newspapers achieve an ideal gray balance.

In the newspaper printing process, the quality of the overall control of the ink-and-wash balance will directly affect the print quality of newspapers. The ink and water balance must be achieved at a certain speed and printing pressure to ensure the newspaper printing quality and the normal production of newspapers. Use the least amount of fountain solution to balance the ink on the printing plate so that the ink emulsifies the fountain solution contained in the ink. Between 15% and 26%.

From an actual point of view, the absolute ink-and-water balance is almost impossible to achieve. It is also difficult to have a universal and accurate quantitative control standard among many factors affecting the ink-water balance. In printing, ink from unbalanced to balanced, and unbalanced, and then adjusted to a new balance, which is adjusted with the changes in various conditions during the printing process, while operators mastered the basic principles of ink and wash balance, It is also necessary to make timely and correct judgments on various situations encountered during operations.

The uniformity of ink depends on the operator's level of adjustment of ink supply. In the quantitative control, according to the national newspaper printing quality standards to determine the value of the density of the field, the use of density meter to measure the density of the field headlines on the layout, so that it is controlled within the scope of the permit.

The balance of gray balance control, ink balance control, and ink uniformity control are closely linked. The "two flat and one uniform" control grasps the quality of newspaper printing in general.

4, the control of raw materials

Any process control only controls the production process. The control of raw materials is a prerequisite for process control. Only the raw materials used are suitable for the actual environment and process conditions of the printing house to ensure the final printing quality of the newspaper. The control of raw materials is mainly control film, PS version, developing and fixing syrup (film and PS version), fountain solution, ink, paper and so on. Any kind of raw materials that need to be used for a long period of time is best to be tested and tried first when purchasing, and then purchased under the condition that the quality is confirmed to ensure that the purchased raw materials can meet the requirements of the printing factory on product quality assurance.

With the establishment of the above four quality control points, a comprehensive and unified overall management has basically formed an orderly and effective quality control system. Of course, a comprehensive and complete printing quality control system still needs to do a lot of meticulous work, and each newspaper printing factory has its own characteristics. Based on the establishment of the above four quality control points, we can build a suitable enterprise based on its own characteristics. The print quality control system.

Operation of quality control system

The establishment of a quality control system is only an establishment of an environment. The smooth operation of a quality control system can eventually lead to a complete quality management system.

The operation of the quality control system relies on a dedicated quality control department to manage, coordinate, supervise and handle the quality accidents of the quality control system in accordance with the printer's own quality documentation system. In the quality management system, the quality control system is the main body, the quality file system is actually its operating environment, and the quality control department performs the functions of quality management.

The quality file system is organized according to the various aspects of the quality control system. It includes the printing company's own quality policy, the procurement standards for printing raw materials, and the process specifications, quality implementation standards, and quality of each production department in the actual production process. Inspection methods and standards, control of non-conforming products, control of the printing environment, correction of quality accidents, and preventive measures.

When the quality control department runs the quality control system, it implements the formulated quality policy and strictly implements quality standards and product inspection procedures. Firstly, the purchased raw materials for printing are inspected, tested and necessary trials are conducted to ensure that the quality of raw materials is suitable for the printing factory's own production environment and standards; and the strict supervision of the process operations of the prepress department, plate making shop, and printing shop is standardized and whether it is based on its own Quality control standards to ensure the printing quality of newspapers; and quality inspections of printed newspapers based on quality control standards, penalties for quality accidents, and prevention and corrective measures.

The openness of the quality control system is particularly important. In actual operation, it is supplemented and improved at any time according to changes and updates in the process conditions, and new technical innovation plans and strategies are proposed and formulated.

At the same time, the good operation of the quality control system requires the participation of all the staff of the printing factory. It is necessary to fully mobilize the quality awareness of all employees and regard itself as a link in quality management. Any employee has the right to reflect the printing quality of the newspaper and propose the right to solve the quality problems and obligations, together around the quality control system to stabilize and improve the newspaper's overall print quality.

Quality is the life of an enterprise. A modern newspaper printing enterprise with an advanced level must rely on a sound and efficient quality management system. The system should and must be a pragmatic system.

Source: HC Business