Prepress preparation is a series of preparations before formal printing. In the gravure printing process, prepress preparation mainly includes: proofreading and installation of the platen roller; configuration of the rubber roller and the doctor blade; preparation of the printing material; and child job such as ink color deployment. Undoubtedly, doing a good job in prepress preparation is a prerequisite for ensuring that printing is carried out normally.
1. Verification and Installation of Plate Roller 1. Verification of the Platen Roller If it is an old plate that has already been printed on, check if the surface of the platen roller has scratches, exposed copper, rust, and peeling of the chrome layer, and promptly notify the plate making plant to handle it accordingly. For the newly made printing plates, it is necessary not only to inspect the roller surface for scratches and bumps, but also to check whether the specifications of the roller and the layout of the plate meet the production requirements, mainly from the following aspects:
(1) Whether the width of the inspection roller and the diameter of the printing roller meet the printing range of the existing printer. In general, the diameter of the plate roller is between 100--200mm easier to print. If the plate diameter is too large, it can easily result in dry printing at low speeds and ink throwing at high speeds. If the size is too small, the printing efficiency will be reduced.
(2) Check whether the plate alignment line and the slitting line of the printing plate can meet the requirements of the later production, and at the same time pay attention to whether the color of the pattern can be recognized by the electric eye in order to cut and make bags.
2. Installation of the Roller When installing the Roller, first install the conical chuck of the fixed roller on the end of the mandrel, the transmission gear, etc., then set the roller from the other end of the mandrel, and install the cone. The chuck and the nut are used to tighten the nut at the same time to prevent the printing roller from affecting the printing accuracy due to loosening of the plate roller. In addition, pay attention to the position of the platen roller on the mandrel so that it is consistent with the position of the other plates. Wipe the copper sleeve, place it on the shaft at both ends of the plate roller and inject mechanical oil. Then, according to the color registration sequence, each plate is properly installed. Note that the plate alignment of each plate is to be installed on the same side of the press.
2. Configuration of rubber roller and squeegee 1. The rubber roller is a roller made of elastic material such as rubber or polyurethane coated on a steel roller. Its role is to complete printing with the printing plate. In the gravure printing process, we usually use the outer diameter of the rubber roller 100-150mm. When configuring the rubber roller, first select the width of the roller according to the width of the plate roller. Under normal circumstances, the two sides of the rubber roller should be about 20mm shorter than the printing plate roller to prevent the roller from getting ink and affecting the printing quality. Secondly, when selecting the rubber roller, the surface of the rubber roller is required to be delicate, smooth, no fine pits and lines and the like.
2. Squeegee Gravure Squeegee Blade is a kind of elastic steel sheet, which is used to scrape excess ink on the plate. Therefore, the configuration of the squeegee blade will directly affect the quality of the printed matter.
(1) Select the squeegee blade. Squeegee blades have a thin (eg, 0.25mm) thin (eg, 0.1mm). In general, the field of thick printing or shallow printing plate, squeegee blades should be thick; fine pen printing or deep printing plate, squeegee blades should be thin.
(2) Cut the squeegee blade according to the plate width of the printing plate. In the gravure printing process, since the blade holder moves back and forth with the plate cylinder axially, the squeegee blades should be about 20 mm longer than the plate cylinder.
(3) Install the squeegee. When installing the squeegee, it is necessary to first clean the support blade and the knife holder to prevent the ink stick from affecting the flatness of the squeegee installation. Under normal circumstances, the support blade extends about 15-25mm from the tool holder, and the squeegee blade extends about 5--8mm more than the support blade. Then put the installed squeegee on the bench and use the fine sandpaper to scrape the burr gap on the blade to make the blade flat. Use rough stone on the front of the blade to grind a bevel angle of about 25 degrees so as to reduce the pressure of the squeegee, prolong the service life of the printing plate, ensure that the squeegee is good, and grind the burr on the back of the blade. Use 600 water sandpaper to polish. Finally, the squeegee is installed on the printing machine, and the blade contact line of the squeegee is required to be parallel to the axis of the gravure roll. The squeegee should be as close as possible to the printing point to prevent the printing ink from drying out. Scraping angle is generally 20 degrees -60 degrees.
3 Preparation of printing materials 1. Determine the variety of printing materials according to the characteristics of the contents of the package The common gravure printing substrates include polyethylene, polypropylene, polyethylene terephthalate, and polyamide. Workers working in this profession must first become familiar with the characteristics of such materials in order to obtain the desired printing effect.
2. According to the user's packaging specifications and layout design, determine the width of the printing material, for example: set the layout is to use the width of the bag after the horizontal layout on the plate, the width of the bag is bcm, when the layout double fight, printing materials Width: 2b + 1.5cm (trilateral seal), 2b +3.5cm (back seal); when the layout 4 fight, the width of the printing material: 4b +1.5cm three-side seal), 4b + 5.5cm (back seal) When the layout 2n fights (n is an integer), the width of the printing material is: 2nb+1.5cm (trilateral seal), (2b+1)n+3.5cm (back seal).
3. According to the user's required number of packages, calculate the amount of printing materials before calculating the amount of printing materials, to understand the specific gravity of the printing materials. For example, polyethylene and polypropylene have a specific gravity of approximately 1 g/cm3; polyethylene terephthalate (PET) has a specific gravity of 1.4 g/cm3; polyamide (PA) has a specific gravity of 1.2 g/cm3, which is generally used in the industry. The film thickness was expressed by silk, 1 filament = 0.001 cm, and the mass of a single bag substrate was calculated according to the formula m = Ïv. Where Ï is the specific gravity of the substrate and v is the volume of the substrate.
For example: do 20,000 25x15x0.008cm PET-PE composite three-side seal bags (double type layout layout), how much kg of PET is needed?
People in the industry know that the thickness of a commonly used PET is 1.2 filaments and the specific gravity is 1.4.
m=20000x(1.4x0.0012x31.5x25)/1000=26.5kg
When slitting a film, sometimes several products are put together in order to get the most economic trimming. At the same time, it should be noted that some films such as PE, PP, etc. need corona treatment before printing to improve the printability, and to measure the surface tension to prevent the surface tension is not enough to make the ink off.
4 Ink color deployment According to the requirements on the printing process, the corresponding ink is selected. If it is an old product, use the remaining ink for the last adjustment and use it. In the case where the amount of ink is not enough, a new ink is prepared according to the ratio on the process sheet, and the ink is mixed with the remaining ink under the condition that the hue is consistent. If it is a new product proofing, it should achieve the customer satisfaction as far as possible, and record the use of the ink manufacturers, models, types and spot color ink ratio one by one, as the basis for formal printing 2. With spot color ink . The use of gravure printing spot color ink is very frequent, so the color matching of ink color is very important and the color matching principle: (1) The color hue of the ink should be the same as the hue ink produced by the ink factory as much as possible because the color and saturation of the styling ink are required. More saturated than two-color inks; (2) If infant inks are used, the color inks should be prepared using the color ink closest to the color; (3) When matching colors, the ink type should be minimized. Because the more color inks are matched, the higher the decolorization ratio, the lower the vividness and saturation of the ink.
In short, doing a good job in prepress preparation is the premise and key to ensure the smooth progress of printing. Only when everything is in place can we ensure good product quality and high production efficiency. At the same time, it will greatly reduce the quality loss.
1. Verification and Installation of Plate Roller 1. Verification of the Platen Roller If it is an old plate that has already been printed on, check if the surface of the platen roller has scratches, exposed copper, rust, and peeling of the chrome layer, and promptly notify the plate making plant to handle it accordingly. For the newly made printing plates, it is necessary not only to inspect the roller surface for scratches and bumps, but also to check whether the specifications of the roller and the layout of the plate meet the production requirements, mainly from the following aspects:
(1) Whether the width of the inspection roller and the diameter of the printing roller meet the printing range of the existing printer. In general, the diameter of the plate roller is between 100--200mm easier to print. If the plate diameter is too large, it can easily result in dry printing at low speeds and ink throwing at high speeds. If the size is too small, the printing efficiency will be reduced.
(2) Check whether the plate alignment line and the slitting line of the printing plate can meet the requirements of the later production, and at the same time pay attention to whether the color of the pattern can be recognized by the electric eye in order to cut and make bags.
2. Installation of the Roller When installing the Roller, first install the conical chuck of the fixed roller on the end of the mandrel, the transmission gear, etc., then set the roller from the other end of the mandrel, and install the cone. The chuck and the nut are used to tighten the nut at the same time to prevent the printing roller from affecting the printing accuracy due to loosening of the plate roller. In addition, pay attention to the position of the platen roller on the mandrel so that it is consistent with the position of the other plates. Wipe the copper sleeve, place it on the shaft at both ends of the plate roller and inject mechanical oil. Then, according to the color registration sequence, each plate is properly installed. Note that the plate alignment of each plate is to be installed on the same side of the press.
2. Configuration of rubber roller and squeegee 1. The rubber roller is a roller made of elastic material such as rubber or polyurethane coated on a steel roller. Its role is to complete printing with the printing plate. In the gravure printing process, we usually use the outer diameter of the rubber roller 100-150mm. When configuring the rubber roller, first select the width of the roller according to the width of the plate roller. Under normal circumstances, the two sides of the rubber roller should be about 20mm shorter than the printing plate roller to prevent the roller from getting ink and affecting the printing quality. Secondly, when selecting the rubber roller, the surface of the rubber roller is required to be delicate, smooth, no fine pits and lines and the like.
2. Squeegee Gravure Squeegee Blade is a kind of elastic steel sheet, which is used to scrape excess ink on the plate. Therefore, the configuration of the squeegee blade will directly affect the quality of the printed matter.
(1) Select the squeegee blade. Squeegee blades have a thin (eg, 0.25mm) thin (eg, 0.1mm). In general, the field of thick printing or shallow printing plate, squeegee blades should be thick; fine pen printing or deep printing plate, squeegee blades should be thin.
(2) Cut the squeegee blade according to the plate width of the printing plate. In the gravure printing process, since the blade holder moves back and forth with the plate cylinder axially, the squeegee blades should be about 20 mm longer than the plate cylinder.
(3) Install the squeegee. When installing the squeegee, it is necessary to first clean the support blade and the knife holder to prevent the ink stick from affecting the flatness of the squeegee installation. Under normal circumstances, the support blade extends about 15-25mm from the tool holder, and the squeegee blade extends about 5--8mm more than the support blade. Then put the installed squeegee on the bench and use the fine sandpaper to scrape the burr gap on the blade to make the blade flat. Use rough stone on the front of the blade to grind a bevel angle of about 25 degrees so as to reduce the pressure of the squeegee, prolong the service life of the printing plate, ensure that the squeegee is good, and grind the burr on the back of the blade. Use 600 water sandpaper to polish. Finally, the squeegee is installed on the printing machine, and the blade contact line of the squeegee is required to be parallel to the axis of the gravure roll. The squeegee should be as close as possible to the printing point to prevent the printing ink from drying out. Scraping angle is generally 20 degrees -60 degrees.
3 Preparation of printing materials 1. Determine the variety of printing materials according to the characteristics of the contents of the package The common gravure printing substrates include polyethylene, polypropylene, polyethylene terephthalate, and polyamide. Workers working in this profession must first become familiar with the characteristics of such materials in order to obtain the desired printing effect.
2. According to the user's packaging specifications and layout design, determine the width of the printing material, for example: set the layout is to use the width of the bag after the horizontal layout on the plate, the width of the bag is bcm, when the layout double fight, printing materials Width: 2b + 1.5cm (trilateral seal), 2b +3.5cm (back seal); when the layout 4 fight, the width of the printing material: 4b +1.5cm three-side seal), 4b + 5.5cm (back seal) When the layout 2n fights (n is an integer), the width of the printing material is: 2nb+1.5cm (trilateral seal), (2b+1)n+3.5cm (back seal).
3. According to the user's required number of packages, calculate the amount of printing materials before calculating the amount of printing materials, to understand the specific gravity of the printing materials. For example, polyethylene and polypropylene have a specific gravity of approximately 1 g/cm3; polyethylene terephthalate (PET) has a specific gravity of 1.4 g/cm3; polyamide (PA) has a specific gravity of 1.2 g/cm3, which is generally used in the industry. The film thickness was expressed by silk, 1 filament = 0.001 cm, and the mass of a single bag substrate was calculated according to the formula m = Ïv. Where Ï is the specific gravity of the substrate and v is the volume of the substrate.
For example: do 20,000 25x15x0.008cm PET-PE composite three-side seal bags (double type layout layout), how much kg of PET is needed?
People in the industry know that the thickness of a commonly used PET is 1.2 filaments and the specific gravity is 1.4.
m=20000x(1.4x0.0012x31.5x25)/1000=26.5kg
When slitting a film, sometimes several products are put together in order to get the most economic trimming. At the same time, it should be noted that some films such as PE, PP, etc. need corona treatment before printing to improve the printability, and to measure the surface tension to prevent the surface tension is not enough to make the ink off.
4 Ink color deployment According to the requirements on the printing process, the corresponding ink is selected. If it is an old product, use the remaining ink for the last adjustment and use it. In the case where the amount of ink is not enough, a new ink is prepared according to the ratio on the process sheet, and the ink is mixed with the remaining ink under the condition that the hue is consistent. If it is a new product proofing, it should achieve the customer satisfaction as far as possible, and record the use of the ink manufacturers, models, types and spot color ink ratio one by one, as the basis for formal printing 2. With spot color ink . The use of gravure printing spot color ink is very frequent, so the color matching of ink color is very important and the color matching principle: (1) The color hue of the ink should be the same as the hue ink produced by the ink factory as much as possible because the color and saturation of the styling ink are required. More saturated than two-color inks; (2) If infant inks are used, the color inks should be prepared using the color ink closest to the color; (3) When matching colors, the ink type should be minimized. Because the more color inks are matched, the higher the decolorization ratio, the lower the vividness and saturation of the ink.
In short, doing a good job in prepress preparation is the premise and key to ensure the smooth progress of printing. Only when everything is in place can we ensure good product quality and high production efficiency. At the same time, it will greatly reduce the quality loss.
Scented Beads,Aroma Beads,Scented Aroma Beads,Clorox Fraganzia Beads
Jiangsu Raymeel Home Decoration Co., Ltd. , https://www.jsraymeelhome.com