The whole process of trademark printing can be roughly divided into four parts: design, plate making, printing and post-press processing. They are interconnected and inseparable. This article briefly describes the characteristics and requirements of the trademark screen printing process.
First, the trademark screen printing design
The trademark screen printing process design has the following characteristics:
1. Design for the end use of the job
Different jobs have different requirements for the used paper. For example, automatic labeling is used for the label of bottled wine. The direction of bending after glueing must be matched with the automatic labeling machine. Otherwise, it cannot be produced on the automatic assembly line.
2. Hollow and mosaic design
Logo design often requires hollowing and inlay processing. In particular, products that require gold (silver) printing must be designed as a hollow version. Otherwise, gold (silver) ink is directly printed on other inks, and the problem of darkening is likely to occur.
3. Match
One of the distinguishing features of trademark printing is the combination of multiple combinations, ranging from two to several, and as many as several dozen. It is more appropriate to determine how many plans are linked together, depending on the process conditions.
(1) The ease of post-processing. If there are many post-processing operations in the job, the layout should not be done too much. Otherwise, due to the poor temperature and humidity control in the printing shop, it is very easy to cause the paper to pump up. This will not only affect overprinting, but also give back stamping and die. Cutting and other processes have caused difficulties in positioning and registration.
(2) Shaped trademarks. The area of ​​the trademark is generally not very large. For the thin paper special-shaped trademark that needs to be die-cut, the combination should not be too much, otherwise the precision of the die-cut production will affect the quality of die-cutting.
(3) Number of prints. If the number of prints is not large, the number of joints cannot be excessive, otherwise the layout is too large and the cost of making a die cut will inevitably increase the cost.
(4) Paper opening count. Due to the influence of the trademark size, it is impossible to accurately combine eight, four, or split editions. Therefore, the principle of selecting the appropriate assembly method should be based on the principle of minimizing printing paper.
It can be seen from the characteristics of the trademark screen printing design that an outstanding trademark designer must not only have innovative design concepts and flexible design skills, but also be familiar with printing and post-press processing technologies, so that the designed trademarks are novel and unique. It also meets the requirements of printing and post-printing processes to avoid unnecessary economic losses. For example, the surrounding of the trademark pattern is too close to the finished product size. Due to the factors such as the paper deformation and the inaccuracy of the die cutting tool, it often results in deflection of the die-cutting product and excessive errors, thus causing the product to be scrapped. When this happens, the designer should adjust and change the design to suit the printing and finishing requirements.
Second, the production of screen printing plate
1. The basic process of photographic emulsion direct plate making
The photographic emulsion direct plate making method is currently a kind of screen printing plate making method that is commonly used in China, and its process flow mainly includes the following points.
(1) Degreasing. Before fabricating the screen, the screen must be degreased with a suitable degreasing agent. Care must be taken not to use household decontamination powders or detergents.
(2) Drying. The degreased wire mesh is rinsed with clean water, and all moisture on the plate is sucked with a gas brush, and then placed in an oven at 30-40[deg.] C. for thorough drying.
(3) coating photosensitive adhesive. The diazo emulsion is evenly applied to the screen using a suitable applicator, usually wet to wet.
(4) Screen drying. The screen plate coated with the emulsion was placed horizontally in a drying oven with the printing face down. The drying temperature should not exceed 40°C.
(5) Screen replenishment. In order to eliminate the unevenness of the photosensitive layer of the screen plate, a layer of sensitized emulsion may be added to the printing surface of the screen plate.
(6) Drying of the screen. Dry the screen again using the same method as the first drying. Note that the drying temperature must not exceed 40 °C.
(7) Screen exposure. The screen is exposed using a suitable light source, such as a metal halide lamp, and the exposure time is determined by a graded exposure.
(8) Screen development. With a suitable water pressure spray gun spray development, the screen on the graphic completely washed out.
(9) Screen drying. Wipe the excess moisture from the screen gently with an unused white paper or absorbent cloth. If it is mass-produced, special equipment is used to suck in moisture, and finally the screen plate is dried in a drying oven.
(10) Revised edition. The water-soluble mesh filler is used to cover the pinholes or other defects present on the screen.
2. The point of direct plate making of emulsion
One of the important factors to be aware of when making a high-quality emulsion screen is that the screen must be uniform and the emulsion should cover the screen completely. It is necessary to first apply the adhesive on the printing surface of the screen 1 to 2 times, and then immediately apply the adhesive on the squeegee surface 2 to 4 times, and wet the wet-squeegee, followed by drying. After drying, it is applied on the printing surface 1 or 2 times to make the thickness of the photosensitive layer reach the final requirement. Each sizing must be performed after the previous adhesive layer has dried. The main factors determining the number of screen printings are the printing requirements and the fineness of the screen, including the following points.
(1) Lines. For prints with a high definition, use a mesh of 90 mesh/cm or finer. In general, the thickness of the photosensitive layer is approximately 15% to 25% of the thickness of the screen, and should generally be between 10 and 18 μm.
(2) Mesh adjustment. Mesh printing requires a thinner ink layer, so the thickness of the photosensitive layer is also very thin, about 10% of the screen thickness, generally 4 ~ 8μm.
(3) UV ink. When printing with UV inks, the amount of ink should be as small as possible. In general, the photosensitive layer on the screen printing surface should not exceed 5 μm.
(4) The quality and fineness of the screen are another important factor in determining the number of coating of the main screen of the screen.
(5) Manual gluing usually uses a scraper bucket. The blade edge of the squeegee must be very sleek, and it should be lifted upwards over the entire length so as to ensure uniform coating on the entire screen surface, including the center of the screen.
(6) Since many diazo sensitizers and their sensitized emulsions have a strong acidic reaction, aluminum scraper buckets are easily damaged, and metal-coated scraper buckets are oxidized after being used for a short period of time. Destruction of the composition of the emulsion, fine foam and scum will appear in the emulsion at this time, so you should use a non-oxidizing type of plastic scraper.
3. Analysis of common failures and causes of direct plate-making of emulsions
(1) fish eye raised after coating
Analysis of the causes: The degreasing of the screen before coating is not complete, or there are dust particles on the screen.
(2) Bubbles appear during the gluing process
Analysis of the reasons: The glue applicator is running too fast and the air is flooded into the mesh to form bubbles. Generally, coarse screens are prone to such problems.
(3) The photosensitive adhesive layer is not firmly adhered after exposure
The reason is analyzed as follows.
1 The photosensitive layer is not completely dry before exposure.
2 The exposure time is too short.
3 The performance of the exposure lamp is not good, the light energy is insufficient, and an optical integrator should be used for exposure.
4 Photosensitivity of the emulsion is poor, and the diazo component is not completely dissolved in water.
5 The air humidity is too high. The painted screen plate feels completely dry when it is touched. It is not completely dry.
(4) Light scattering causes loss of fine-grained images on the screen
Analysis of Causes: When printing, the use of white screens is prone to light scattering, and orange screens are used to minimize light scattering. However, compared with the white screen, the exposure time of the dyed screen is increased by 75% to 100%.
(5) sawtooth effect
Analysis of the reasons: The photographic emulsion is not well-squeegeed and the photosensitive layer of the screen printing surface may be too thin.
(6) The halftone printing dots stick to each other
Analysis of the reasons: When screen printing is required, the photosensitive layer of the screen is required to be thinner, and if necessary, the number of times that the photoresist is applied may also be reduced. If the photoresist layer is thick, the amount of ink that adheres during printing is excessive, resulting in the adhesion of dots to each other, especially in the dark image area. This phenomenon is more obvious.
(7) Difficult to release film
The reason is analyzed as follows.
1 After the printing, the screen plate was not washed in time, or was not completely washed. Some of the ink was dried on the screen plate.
2 Due to the influence of the solvent, the screen plate still contains ink, and the release film cannot dissolve the photosensitive adhesive. Before the film is removed, the degreasing must be performed again.
3 The release fluid is not suitable.
First, the trademark screen printing design
The trademark screen printing process design has the following characteristics:
1. Design for the end use of the job
Different jobs have different requirements for the used paper. For example, automatic labeling is used for the label of bottled wine. The direction of bending after glueing must be matched with the automatic labeling machine. Otherwise, it cannot be produced on the automatic assembly line.
2. Hollow and mosaic design
Logo design often requires hollowing and inlay processing. In particular, products that require gold (silver) printing must be designed as a hollow version. Otherwise, gold (silver) ink is directly printed on other inks, and the problem of darkening is likely to occur.
3. Match
One of the distinguishing features of trademark printing is the combination of multiple combinations, ranging from two to several, and as many as several dozen. It is more appropriate to determine how many plans are linked together, depending on the process conditions.
(1) The ease of post-processing. If there are many post-processing operations in the job, the layout should not be done too much. Otherwise, due to the poor temperature and humidity control in the printing shop, it is very easy to cause the paper to pump up. This will not only affect overprinting, but also give back stamping and die. Cutting and other processes have caused difficulties in positioning and registration.
(2) Shaped trademarks. The area of ​​the trademark is generally not very large. For the thin paper special-shaped trademark that needs to be die-cut, the combination should not be too much, otherwise the precision of the die-cut production will affect the quality of die-cutting.
(3) Number of prints. If the number of prints is not large, the number of joints cannot be excessive, otherwise the layout is too large and the cost of making a die cut will inevitably increase the cost.
(4) Paper opening count. Due to the influence of the trademark size, it is impossible to accurately combine eight, four, or split editions. Therefore, the principle of selecting the appropriate assembly method should be based on the principle of minimizing printing paper.
It can be seen from the characteristics of the trademark screen printing design that an outstanding trademark designer must not only have innovative design concepts and flexible design skills, but also be familiar with printing and post-press processing technologies, so that the designed trademarks are novel and unique. It also meets the requirements of printing and post-printing processes to avoid unnecessary economic losses. For example, the surrounding of the trademark pattern is too close to the finished product size. Due to the factors such as the paper deformation and the inaccuracy of the die cutting tool, it often results in deflection of the die-cutting product and excessive errors, thus causing the product to be scrapped. When this happens, the designer should adjust and change the design to suit the printing and finishing requirements.
Second, the production of screen printing plate
1. The basic process of photographic emulsion direct plate making
The photographic emulsion direct plate making method is currently a kind of screen printing plate making method that is commonly used in China, and its process flow mainly includes the following points.
(1) Degreasing. Before fabricating the screen, the screen must be degreased with a suitable degreasing agent. Care must be taken not to use household decontamination powders or detergents.
(2) Drying. The degreased wire mesh is rinsed with clean water, and all moisture on the plate is sucked with a gas brush, and then placed in an oven at 30-40[deg.] C. for thorough drying.
(3) coating photosensitive adhesive. The diazo emulsion is evenly applied to the screen using a suitable applicator, usually wet to wet.
(4) Screen drying. The screen plate coated with the emulsion was placed horizontally in a drying oven with the printing face down. The drying temperature should not exceed 40°C.
(5) Screen replenishment. In order to eliminate the unevenness of the photosensitive layer of the screen plate, a layer of sensitized emulsion may be added to the printing surface of the screen plate.
(6) Drying of the screen. Dry the screen again using the same method as the first drying. Note that the drying temperature must not exceed 40 °C.
(7) Screen exposure. The screen is exposed using a suitable light source, such as a metal halide lamp, and the exposure time is determined by a graded exposure.
(8) Screen development. With a suitable water pressure spray gun spray development, the screen on the graphic completely washed out.
(9) Screen drying. Wipe the excess moisture from the screen gently with an unused white paper or absorbent cloth. If it is mass-produced, special equipment is used to suck in moisture, and finally the screen plate is dried in a drying oven.
(10) Revised edition. The water-soluble mesh filler is used to cover the pinholes or other defects present on the screen.
2. The point of direct plate making of emulsion
One of the important factors to be aware of when making a high-quality emulsion screen is that the screen must be uniform and the emulsion should cover the screen completely. It is necessary to first apply the adhesive on the printing surface of the screen 1 to 2 times, and then immediately apply the adhesive on the squeegee surface 2 to 4 times, and wet the wet-squeegee, followed by drying. After drying, it is applied on the printing surface 1 or 2 times to make the thickness of the photosensitive layer reach the final requirement. Each sizing must be performed after the previous adhesive layer has dried. The main factors determining the number of screen printings are the printing requirements and the fineness of the screen, including the following points.
(1) Lines. For prints with a high definition, use a mesh of 90 mesh/cm or finer. In general, the thickness of the photosensitive layer is approximately 15% to 25% of the thickness of the screen, and should generally be between 10 and 18 μm.
(2) Mesh adjustment. Mesh printing requires a thinner ink layer, so the thickness of the photosensitive layer is also very thin, about 10% of the screen thickness, generally 4 ~ 8μm.
(3) UV ink. When printing with UV inks, the amount of ink should be as small as possible. In general, the photosensitive layer on the screen printing surface should not exceed 5 μm.
(4) The quality and fineness of the screen are another important factor in determining the number of coating of the main screen of the screen.
(5) Manual gluing usually uses a scraper bucket. The blade edge of the squeegee must be very sleek, and it should be lifted upwards over the entire length so as to ensure uniform coating on the entire screen surface, including the center of the screen.
(6) Since many diazo sensitizers and their sensitized emulsions have a strong acidic reaction, aluminum scraper buckets are easily damaged, and metal-coated scraper buckets are oxidized after being used for a short period of time. Destruction of the composition of the emulsion, fine foam and scum will appear in the emulsion at this time, so you should use a non-oxidizing type of plastic scraper.
3. Analysis of common failures and causes of direct plate-making of emulsions
(1) fish eye raised after coating
Analysis of the causes: The degreasing of the screen before coating is not complete, or there are dust particles on the screen.
(2) Bubbles appear during the gluing process
Analysis of the reasons: The glue applicator is running too fast and the air is flooded into the mesh to form bubbles. Generally, coarse screens are prone to such problems.
(3) The photosensitive adhesive layer is not firmly adhered after exposure
The reason is analyzed as follows.
1 The photosensitive layer is not completely dry before exposure.
2 The exposure time is too short.
3 The performance of the exposure lamp is not good, the light energy is insufficient, and an optical integrator should be used for exposure.
4 Photosensitivity of the emulsion is poor, and the diazo component is not completely dissolved in water.
5 The air humidity is too high. The painted screen plate feels completely dry when it is touched. It is not completely dry.
(4) Light scattering causes loss of fine-grained images on the screen
Analysis of Causes: When printing, the use of white screens is prone to light scattering, and orange screens are used to minimize light scattering. However, compared with the white screen, the exposure time of the dyed screen is increased by 75% to 100%.
(5) sawtooth effect
Analysis of the reasons: The photographic emulsion is not well-squeegeed and the photosensitive layer of the screen printing surface may be too thin.
(6) The halftone printing dots stick to each other
Analysis of the reasons: When screen printing is required, the photosensitive layer of the screen is required to be thinner, and if necessary, the number of times that the photoresist is applied may also be reduced. If the photoresist layer is thick, the amount of ink that adheres during printing is excessive, resulting in the adhesion of dots to each other, especially in the dark image area. This phenomenon is more obvious.
(7) Difficult to release film
The reason is analyzed as follows.
1 After the printing, the screen plate was not washed in time, or was not completely washed. Some of the ink was dried on the screen plate.
2 Due to the influence of the solvent, the screen plate still contains ink, and the release film cannot dissolve the photosensitive adhesive. Before the film is removed, the degreasing must be performed again.
3 The release fluid is not suitable.
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