Fault case
Recently, a two-color machine of our factory has produced a ghost image, which is special. Now we describe its phenomena, causes and exclusion methods for reference by peers.
When we print a batch of four colors, we need to print real yellow and black first, taking into account the process requirements. The yellow version has an area of ​​530mm×80mm (the paper size is 560mm×40mm). The black version has only one row of text, 170mm away from the mouth, and the font size is about 10mm square. There are two 30mm square bold characters on the 300mm outer distance mouthpiece. And a vertical bar of 60mm x mm. We put black in the coloring group and yellow in the color group. At the time of starting printing, a ghosting fault appeared, characterized by two rows of ghosts appearing in a row of black letters at the mouth of the cornice and 382mm from the cornices, and ghosts appearing at the longitudinal trailing edges of the outer characters and black bars. About 300 prints were made and ghosting was fixed. Stop for the reason, there is no problem with the plate. From the analysis of the characteristics of ghosting, there is no possibility that the printing plate is not tightened, the blanket is not tight, and the roller is shaken. That would not be caused by poor ink printability and cause ghosting? So go up and stir the ink in the ink fountain and find that it is very fluid and the viscosity is too small. After asking the operators, due to the cold weather on that day, the ambient temperature was lower than -8 degrees Celsius, the workshop was only 10 degrees Celsius, and a lot of No. 6 varnish was added to change the ink compatibility. From this, it was initially determined that the ink was ghosted. After cleaning the ink roller and replacing the ink, the situation has improved and the ghosting has been reduced. After the water roller was replaced again, ghosting was eliminated and printing was normal.
The reason is mainly caused by ink ghosting. Ink was added with an excessive amount of ink, the fluidity, decreased, so that the ink on the printing plate is not firmly ink, resulting in some of the ink transferred to the water roller by the printing plate, in the water while the printing plate for the second ink, Thus, a fixed ghost image with a light but clear footprint appears, and the distance between the ghost image and the normal print is about 210 mm, which is exactly equal to the circumference of the water roller.
This example tells us that the amount of ink adjuvant must be appropriate in the cold winter season, especially in the poor offset printing workshop. When the temperature is low, the ink is very hard. In order to improve its printability, a proper amount of varnish is added to the resume, but do not add more, because the machine will generate a certain amount of frictional heat and can change the ink accordingly. Temperature, viscosity, fluidity and other physical properties. If you add too much other auxiliary dose such as varnish or detackifier, some unexpected failures can occur, affecting the normal production schedule.
Experience summary
In the cold winter season, especially when printing in some poor-quality offset printing workshops, the amount of ink adjuvant must be appropriate. When the temperature is low, the ink is very hard. In order to improve its printability, a proper amount of varnish is added to the resume, but do not add more, because the machine will generate a certain amount of frictional heat and can change the ink accordingly. Temperature, viscosity, fluidity and other physical properties. If you add too much other auxiliary dose such as varnish or detackifier, some unexpected failures can occur, affecting the normal production schedule.
Recently, a two-color machine of our factory has produced a ghost image, which is special. Now we describe its phenomena, causes and exclusion methods for reference by peers.
When we print a batch of four colors, we need to print real yellow and black first, taking into account the process requirements. The yellow version has an area of ​​530mm×80mm (the paper size is 560mm×40mm). The black version has only one row of text, 170mm away from the mouth, and the font size is about 10mm square. There are two 30mm square bold characters on the 300mm outer distance mouthpiece. And a vertical bar of 60mm x mm. We put black in the coloring group and yellow in the color group. At the time of starting printing, a ghosting fault appeared, characterized by two rows of ghosts appearing in a row of black letters at the mouth of the cornice and 382mm from the cornices, and ghosts appearing at the longitudinal trailing edges of the outer characters and black bars. About 300 prints were made and ghosting was fixed. Stop for the reason, there is no problem with the plate. From the analysis of the characteristics of ghosting, there is no possibility that the printing plate is not tightened, the blanket is not tight, and the roller is shaken. That would not be caused by poor ink printability and cause ghosting? So go up and stir the ink in the ink fountain and find that it is very fluid and the viscosity is too small. After asking the operators, due to the cold weather on that day, the ambient temperature was lower than -8 degrees Celsius, the workshop was only 10 degrees Celsius, and a lot of No. 6 varnish was added to change the ink compatibility. From this, it was initially determined that the ink was ghosted. After cleaning the ink roller and replacing the ink, the situation has improved and the ghosting has been reduced. After the water roller was replaced again, ghosting was eliminated and printing was normal.
The reason is mainly caused by ink ghosting. Ink was added with an excessive amount of ink, the fluidity, decreased, so that the ink on the printing plate is not firmly ink, resulting in some of the ink transferred to the water roller by the printing plate, in the water while the printing plate for the second ink, Thus, a fixed ghost image with a light but clear footprint appears, and the distance between the ghost image and the normal print is about 210 mm, which is exactly equal to the circumference of the water roller.
This example tells us that the amount of ink adjuvant must be appropriate in the cold winter season, especially in the poor offset printing workshop. When the temperature is low, the ink is very hard. In order to improve its printability, a proper amount of varnish is added to the resume, but do not add more, because the machine will generate a certain amount of frictional heat and can change the ink accordingly. Temperature, viscosity, fluidity and other physical properties. If you add too much other auxiliary dose such as varnish or detackifier, some unexpected failures can occur, affecting the normal production schedule.
Experience summary
In the cold winter season, especially when printing in some poor-quality offset printing workshops, the amount of ink adjuvant must be appropriate. When the temperature is low, the ink is very hard. In order to improve its printability, a proper amount of varnish is added to the resume, but do not add more, because the machine will generate a certain amount of frictional heat and can change the ink accordingly. Temperature, viscosity, fluidity and other physical properties. If you add too much other auxiliary dose such as varnish or detackifier, some unexpected failures can occur, affecting the normal production schedule.
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Guangzhou Athena Cosmetics Manufacturing Co.,Ltd is a subsidiary of YALAN international group which is located in Guangzhou,china.it is the production center of YALAN international group branding products,specialized in the development and production if cosmetics.ATHENA is qualified for import and export.
controls the quality in full accordance with GMP, ISO9001 quality system good manufacturing practice for cosmetics and key points of cosmetic production licence inspection.
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Athena(Guangzhou) Cosmetics Manufacturer Co., Ltd , http://www.ydgzathenaskincare.com