Printing dot processing method

Abstract

The invention relates to the technical field of printing dot processing, and particularly discloses a printing dot processing method which comprises the following steps: step 1, manuscript analysis: evaluating a printing manuscript, and determining a color mode of the manuscript; equipment and materials are prepared, specifically, proper plate making equipment including a laser typesetter and CTP equipment is selected, printing plate materials are prepared, proper printing ink is selected, and different printing product types have different requirements for the printing ink; 2, image-text information processing, wherein professional image processing software is used for processing the manuscript, and dot types are set in the software; determining dot parameters according to the requirements of the printed matter; and during color correction and tone adjustment, the printed matter can accurately restore the color and hierarchy of the manuscript. Through the steps, high-resolution scanning is carried out on the manuscript, the dot angle setting of each color plate is reasonable, the dot angle difference of the two color plates is not too small, and the problem of interference fringes on a printed matter is avoided.

Description

Technical Field

[0001] The invention relates to the technical field of printing dot processing, in particular to a printing dot processing method. Background Art

[0002] Printing dots are the basic units used to present image colors, layers and contours during the printing process.

[0003] In the process of printing dot printing, as the working time unfolds, when scanning the original information, due to the lack of calibration of the scanning equipment, it is easy to cause low scanning resolution and blurred development, resulting in unreasonable subsequent dot settings. Therefore, we propose a printing dot processing method. Summary of the invention

[0004] The purpose of the present invention is to solve the shortcomings of the prior art and to propose a printing dot processing method and production process.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: A printing dot processing method comprises the following steps: Step 1: Original analysis: Evaluate the printed original and determine the color mode of the original; Equipment and material preparation: Select appropriate platemaking equipment including laser imagesetters and CTP equipment, prepare printing plate materials, and select appropriate inks. Different types of printed products have different requirements for inks. Step 2: Graphic information processing: Use professional image processing software to process the original, set the dot type in the software; determine the dot parameters according to the requirements of the printed product; during color correction and gradation adjustment, ensure that the printed product can accurately restore the color and level of the original, and change the brightness and contrast of the image by adjusting the curve tool to optimize the distribution of dots in different tonal areas; Exposure imaging: The processed graphic information is output to the film through the laser imagesetter. The laser imagesetter controls the intensity and exposure time of the laser beam according to the digital signal to form a dot image on the film. The film is placed on the printing plate coated with photosensitive material for exposure. During exposure, the light passes through the dot part on the film, causing the photosensitive layer of the printing plate to undergo a photochemical reaction. The laser imagesetter is calibrated regularly to ensure its scanning accuracy. The calibration includes color calibration and optical system calibration. Color calibration uses professional color calibration tools, and optical system calibration is to adjust the lens, light source and other components. Development: After exposure, the plate is developed. The plate is placed in a developer, and the unexposed photosensitive material will be dissolved, while the exposed part will remain. Step 3: Plate loading and debugging: The prepared printing plate is installed on the plate cylinder of the printing press, and then the printing press is debugged. The debugging scope includes the adjustment of the ink supply system, and the precise control of the ink supply according to the coverage and color requirements of the dots; Printing operation: Start the printing press, and the ink is transferred to the rubber blanket through the dots on the printing plate, and then transferred from the rubber blanket to the printing paper or other substrates. During the printing process, pay attention to the transfer of dots and whether there are problems such as dot loss, expansion and deformation. For multi-color printing, printing should be carried out in a certain order. After each color is printed, the registration of the dots should be checked to ensure that the dots of different colors can be accurately superimposed to achieve accurate color reproduction; Step 4: Printed product sampling inspection: During the printing process, regularly take samples of printed products for inspection, use a magnifying glass and a microscope to observe the quality of the dots, check whether the shape of the dots is complete, whether the size meets the requirements, and whether the distribution is uniform; check the color accuracy of the printed products, use a color measuring instrument to measure the color values ​​of different areas on the printed products, compare them with the standard color values, and determine whether there is color deviation; Adjustment and correction: When problems of dot enlargement and shrinkage are found, corrections are made by adjusting the pressure and ink supply parameters of the printing press; color deviations are corrected by adjusting the color ratio of the ink; for some serious quality problems, including dot damage caused by plate wear, it is necessary to re-plate and then print; Step 5: According to the size requirements of the printed material, use a cutter to cut the printed paper or roll material into the required size, and remove the excess edges and blank parts.

[0006] Preferably, in the step 1, the manuscripts in the manuscript analysis include photos, paintings and electronic documents, and if the color mode is not in CMKY format, it needs to be converted into CMKY format.

[0007] Preferably, in the step 1, the CTP equipment in the equipment and material preparation analysis can directly convert the digital file into a printing plate, reducing the intermediate links and improving the plate making accuracy; the printing plate includes an aluminum plate, and the aluminum plate needs to be surface treated to make it have good hydrophilicity and ink affinity to ensure that the dots can accurately transfer ink; the properties of the ink include viscosity, drying speed and color saturation, which will affect the reproduction quality of the dots; the types of printed materials include newspapers, picture albums and packaging Preferably, the image processing software in the graphic information processing in step 2 includes Adobe Photoshop and Illustrator, and the dot types include amplitude modulation dots, frequency modulation dots and mixed screening. For amplitude modulation dots, the dot size and screening angle must be set; for frequency modulation dots, the frequency of the dots must be determined.

[0008] Preferably, the exposure imaging in step 2 is aimed at traditional plate making. When using CTP equipment, there is no need to output the graphic information to the film through a laser imagesetter.

[0009] Preferably, the exposed portion in the development of step 2 is the portion where dots are formed, and the concentration, temperature and development time of the developer have an impact on the quality of the dots.

[0010] Preferably, during the printing plate installation process of step three, the printing plate should be firmly installed and accurately positioned to ensure that the dots can correctly transfer ink, and multi-color printing is performed during the printing operation of step three.

[0011] Preferably, in the step 3 of sampling inspection of printed matter, the color measuring instrument used is a spectrophotometer.

[0012] Preferably, during the surface treatment of the aluminum material, a hydrophilic coating is first applied by dipping or spraying to form a thin film with good hydrophilicity after drying, and then an ink-repellent coating is applied on the hydrophilic coating, with a coating thickness of about 6-10 μm.

[0013] Compared with the prior art, the present invention has the following beneficial effects: The present invention performs high-resolution scanning on the original through the above steps, and the dot angles of each color plate are reasonably set, so that the dot angle difference between two color plates will not be too small, and the problem of interference fringes will not appear on the printed product. DETAILED DESCRIPTION

[0014] The technical solutions in the embodiments of the present invention will be clearly and completely described below in combination with the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments.

[0015] Please refer to a printing dot processing method, comprising the following steps: Step 1: Original analysis: Evaluate the printed original and determine the color mode of the original; Equipment and material preparation: Select appropriate platemaking equipment including laser imagesetters and CTP equipment, prepare printing plate materials, and select appropriate inks. Different types of printed products have different requirements for inks. Step 2: Graphic information processing: Use professional image processing software to process the original, set the dot type in the software; determine the dot parameters according to the requirements of the printed product; during color correction and gradation adjustment, ensure that the printed product can accurately restore the color and level of the original, and change the brightness and contrast of the image by adjusting the curve tool to optimize the distribution of dots in different tonal areas; Exposure imaging: The processed graphic information is output to the film through the laser phototypesetter. The laser phototypesetter controls the intensity and exposure time of the laser beam according to the digital signal to form a dot image on the film. The film is placed on the printing plate coated with photosensitive material for exposure. During exposure, the light passes through the dot part on the film, causing the photosensitive layer of the printing plate to undergo a photochemical reaction. The laser phototypesetter is calibrated regularly to ensure its scanning accuracy. Calibration includes color calibration and optical system calibration. Color calibration uses professional color calibration tools. Optical system calibration is to adjust components such as lenses and light sources. For example, ensure that the brightness of the light source is uniform and the lens is free of dust or scratches. When the light source is uneven, the brightness of the scanned image will be inconsistent, and defects on the lens will affect the clarity of the image and reduce the actual effect of resolution. Development: After exposure, the plate is developed. The plate is placed in a developer, and the unexposed photosensitive material will be dissolved, while the exposed part will remain. Step 3: Plate loading and debugging: The prepared printing plate is installed on the plate cylinder of the printing press, and then the printing press is debugged. The debugging scope includes the adjustment of the ink supply system. According to the coverage rate and color requirements of the dots, the ink supply amount is accurately controlled. For areas with high dot coverage, more ink needs to be provided. At the same time, the printing pressure needs to be adjusted. Appropriate printing pressure can ensure the clear transfer of dots. Excessive pressure may cause the dots to expand, and too little pressure will result in insufficient ink transfer. Printing operation: Start the printing press, and the ink is transferred to the rubber blanket through the dots on the printing plate, and then transferred from the rubber blanket to the printing paper or other substrates. During the printing process, pay attention to the transfer of dots and whether there are problems such as dot loss, expansion and deformation. For multi-color printing, printing should be carried out in a certain order. After each color is printed, the registration of the dots should be checked to ensure that the dots of different colors can be accurately superimposed to achieve accurate color reproduction; Step 4: Printed product sampling inspection: During the printing process, regularly take samples of printed products for inspection, use a magnifying glass and a microscope to observe the quality of the dots, check whether the shape of the dots is complete, whether the size meets the requirements, and whether the distribution is uniform; check the color accuracy of the printed products, use a color measuring instrument to measure the color values ​​of different areas on the printed products, compare them with the standard color values, and determine whether there is color deviation; Adjustment and correction: When problems of dot enlargement and shrinkage are found, corrections are made by adjusting the pressure and ink supply parameters of the printing press; color deviations are corrected by adjusting the color ratio of the ink; for some serious quality problems, including dot damage caused by plate wear, it is necessary to re-plate and then print; Step 5: According to the size requirements of the printed material, use a cutter to cut the printed paper or roll material into the required size, and remove the excess edges and blank parts.

[0016] As a technical optimization solution of the present invention, in step 1, in the manuscript analysis, the manuscript includes photos, paintings and electronic documents, and the color mode is not in CMKY format and needs to be converted into CMKY format.

[0017] As a technical optimization solution of the present invention, in the step 1 equipment and material preparation analysis, the CTP equipment can directly convert the digital file into a printing plate, reducing the intermediate links and improving the plate making accuracy; the printing plate includes an aluminum plate, and the aluminum plate needs to be surface treated to have good hydrophilicity and ink affinity to ensure that the dots can accurately transfer ink; the properties of the ink include viscosity, drying speed and color saturation, which will affect the reproduction quality of the dots; the types of printed materials include newspapers, picture albums and packaging.

[0018] As a technical optimization scheme of the present invention, in step 2, the image processing software in the graphic information processing includes Adobe Photoshop and Illustrator, and the dot types include amplitude modulation dots, frequency modulation dots and mixed screening. For amplitude modulation dots, the dot size (expressed as a percentage of dots from 0% to 100%) and the screening angle need to be set; for frequency modulation dots, the frequency of the dots (the number of dots per unit area) needs to be determined; different printing processes have different requirements for dot angles. In gravure printing, due to the particularity of the printing method, the selection of dot angles needs to consider the filling and transfer of ink in the pits. The dots of gravure printing are realized by engraving pits of different depths on the plate cylinder. The dot angle will affect the effect of ink transfer from the pits to the substrate, and the characteristics of the printing material will also affect the selection of the dot angle; when using paper with a rough surface, the dots may be deformed during the transfer process. In this case, in order to reduce the impact of dot deformation on printing quality, the dot angle needs to be adjusted to make the distribution of dots on the paper surface more reasonable to ensure the correct reproduction of color and level.

[0019] As a technical optimization solution of the present invention, step 2 of exposure imaging is aimed at traditional plate making. When using CTP equipment, there is no need to output the graphic information to the film through a laser typesetter; the length of exposure time will affect the quality of the dots. Too long time will cause the dots to expand, and too short time will make the dots unclear. Traditional plate making is based on film to transmit graphic information. The graphic information in the computer is output to the film through a laser typesetter. The graphic part on the film has different degrees of occlusion of light, and the graphic information on the film is used to expose the printing plate coated with photosensitive material.

[0020] As a technical optimization scheme of the present invention, the exposed part in the development of step 2 is the part that forms the dots. At the same time, the concentration, temperature and development time of the developer have an impact on the quality of the dots. Too high a concentration of the developer may excessively corrode the printing plate, causing the dots to become smaller or deformed. Too high a temperature may accelerate the development speed, making the dot quality difficult to control.

[0021] As a technical optimization solution of the present invention, during the printing plate installation process of step 3, the printing plate should be firmly installed and accurately positioned to ensure that the dots can correctly transfer ink. In the printing operation of step 3, multi-color printing, such as four-color printing, is to print black first, then cyan, magenta and yellow. After each color is printed, the registration of the dots should be checked to ensure that the dots of different colors can be accurately superimposed to achieve accurate color reproduction. In four-color printing, the dot angle of the black plate (K) is set to 45°, because the human eye is sensitive to 45°. The lines and dots in the right and left directions are the most sensitive. Setting the black plate at this angle will give the best visual effect to the black part. At the same time, the black plate is usually used to emphasize the outline and dark parts in the image. This angle setting helps to enhance the layering and three-dimensional sense of the image. The dot angle of the cyan (C) plate is often set to 15°, the magenta (M) plate is set to 75°, and the yellow (Y) plate is set to 90°. This angle combination is selected based on the relationship between colors and visual characteristics. By staggering the dot angles of each color plate, the appearance of moire can be minimized.

[0022] As a technical optimization solution of the present invention, in step three of the printed product sampling inspection, the color measuring instrument used is a spectrophotometer.

[0023] As a technical optimization scheme of the present invention, when treating the surface of aluminum, a hydrophilic coating, such as a polyvinyl alcohol coating, is first applied. Vinyl alcohol is dissolved in water to prepare a 6%-12% solution, which is applied by dipping or spraying. After drying, a thin film with good hydrophilicity is formed. Then, an ink-receptive coating is applied on the hydrophilic coating. A polyurethane coating containing a carbamate group is used, which can form chemical bonds or physical adsorption with the components in the ink. The polyurethane coating can be applied after mixing two components. The two components are mixed in a certain ratio (such as 1:1.25-1:1.6), and the coating thickness is about 6-10μm.

[0024] When the present invention is used, the original is scanned at high resolution through regular calibration. Meanwhile, the dot angles of each color plate are reasonably set, so that the dot angle difference between two color plates will not be too small, and interference fringes will not appear on the printed product.

[0025] The above are only preferred specific implementation modes of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical solutions and inventive concepts of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A printing dot processing method, characterized in that: The steps include: Step 1: Original analysis: Evaluate the printed original and determine the color mode of the original; Equipment and material preparation: Select appropriate platemaking equipment including laser imagesetters and CTP equipment, prepare printing plate materials, and select appropriate inks. Different types of printed products have different requirements for inks. Step 2: Graphic information processing: Use professional image processing software to process the original, set the dot type in the software; determine the dot parameters according to the requirements of the printed product; during color correction and gradation adjustment, ensure that the printed product can accurately restore the color and level of the original, and change the brightness and contrast of the image by adjusting the curve tool to optimize the distribution of dots in different tonal areas; Exposure imaging: The processed graphic information is output to the film through the laser imagesetter. The laser imagesetter controls the intensity and exposure time of the laser beam according to the digital signal to form a dot image on the film. The film is placed on the printing plate coated with photosensitive material for exposure. During exposure, the light passes through the dot part on the film, causing the photosensitive layer of the printing plate to undergo a photochemical reaction. The laser imagesetter is calibrated regularly to ensure its scanning accuracy. The calibration includes color calibration and optical system calibration. Color calibration uses professional color calibration tools, and optical system calibration is to adjust the lens, light source and other components. Development: After exposure, the plate is developed. The plate is placed in a developer, and the unexposed photosensitive material will be dissolved, while the exposed part will remain. Step 3: Plate loading and debugging: The prepared printing plate is installed on the plate cylinder of the printing press, and then the printing press is debugged. The debugging scope includes the adjustment of the ink supply system, and the precise control of the ink supply according to the coverage and color requirements of the dots; Printing operation: Start the printing press, and the ink is transferred to the rubber blanket through the dots on the printing plate, and then transferred from the rubber blanket to the printing paper or other substrates. During the printing process, pay attention to the transfer of dots and whether there are problems such as dot loss, expansion and deformation. For multi-color printing, printing should be carried out in a certain order. After each color is printed, the registration of the dots should be checked to ensure that the dots of different colors can be accurately superimposed to achieve accurate color reproduction; Step 4: Printed product sampling inspection: During the printing process, regularly take samples of printed products for inspection, use a magnifying glass and a microscope to observe the quality of the dots, check whether the shape of the dots is complete, whether the size meets the requirements, and whether the distribution is uniform; check the color accuracy of the printed products, use a color measuring instrument to measure the color values ​​of different areas on the printed products, compare them with the standard color values, and determine whether there is color deviation; Adjustment and correction: When problems of dot enlargement and shrinkage are found, corrections are made by adjusting the pressure and ink supply parameters of the printing press; color deviations are corrected by adjusting the color ratio of the ink; for some serious quality problems, including dot damage caused by plate wear, it is necessary to re-plate and then print; Step 5: According to the size requirements of the printed material, use a cutter to cut the printed paper or roll material into the required size, and remove the excess edges and blank parts.

2. A printing dot processing method according to claim 1, characterized in that: In the step 1, the originals in the original analysis include photos, paintings and electronic documents, and the color mode is not in CMKY format and needs to be converted into CMKY format.

3. A printing dot processing method according to claim 1, characterized in that: In the step 1, the CTP equipment can directly convert the digital file into a printing plate, which reduces the intermediate links and improves the plate making accuracy. The printing plate includes an aluminum plate, and the aluminum plate needs to be surface treated to make it have good hydrophilicity and ink affinity to ensure that the dots can accurately transfer ink. Ink properties include viscosity, drying speed and color saturation, all of which affect the quality of dot reproduction; print types include newspapers, brochures and packaging.

4. A printing dot processing method according to claim 1, characterized in that: In the step 2 of processing graphic information, the image processing software includes Adobe Photoshop and Illustrator, and the dot types include AM dots, FM dots and mixed screening. For AM dots, the dot size and screening angle need to be set; for FM dots, the frequency of the dots needs to be determined.

5. A printing dot processing method according to claim 1, characterized in that: The exposure imaging in step 2 is aimed at traditional plate making. When using CTP equipment, there is no need to output the graphic information to the film through a laser imagesetter.

6. A printing dot processing method according to claim 1, characterized in that: The exposed part in the development of step 2 is the part where dots are formed. Meanwhile, the concentration, temperature and development time of the developer have an impact on the quality of the dots.

7. A printing dot processing method according to claim 1, characterized in that: During the printing plate installation process of step three, plate loading and debugging, it is necessary to ensure that the printing plate is installed firmly and positioned accurately to ensure that the dots can transfer ink correctly. In step three, multi-color printing is performed during the printing operation.

8. A printing dot processing method according to claim 1, characterized in that: In the step 3 of the printed matter sampling inspection, the color measuring instrument used is a spectrophotometer.

9. A printing dot processing method according to claim 3, characterized in that: When treating the aluminum surface, a hydrophilic coating is first applied by dipping or spraying to form a thin film with good hydrophilicity after drying. Then, an ink-repellent coating is applied on the hydrophilic coating. The coating thickness is 6-10 μm.