Matters needing attention in the production process of cotton digital printing
The application of industrial-grade digital technology in printing is a "technical revolution" in the textile printing industry. After years of development, it has gradually shifted from the past design, proofing, and small batch production mode to mass production mode, and the overall development is getting faster and faster. In the actual production process, digital printing also has many problems and needs to be improved. So, what are the precautions in the production process of all-cotton digital printing?
1.Grey cloth and pre-treatment
In addition to the conventional singeing finish, whiteness, PH, weft skew, wool effect and other requirements, pay special attention to:
① You should choose a good grade cotton yarn and a grey fabric with a reasonable weaving process, which will greatly help the color amount and uniform color on the printed fabric.
②The problems of cotton heads, thick stems and slub yarn on grey fabrics are obviously exposed on the ground in digital printing, especially in dark colors. White spots and shallow stems are obvious after washing. It is necessary to choose good quality grey cloth, strengthen the singeing treatment, and strengthen the scouring treatment to prevent problems such as white spots and shallow stems on the cloth surface.
③The burrs of digital printing semi-finished products should not be too long. If necessary, choose effective methods such as burning, trimming, and pressing to prevent the burrs from being too long and causing the machine to stop or even rub the print head and cause damage.
2.Sizing process and sizing equipment
①Sizing requirements: uniform sizing on the left, middle and right of the cloth surface, uniform drying at front and rear speeds, neat rolling, minimum weft skew, convenient printing and patching, the sizing cloth is less affected by environmental humidity, high color yield, and non-bleeding , Does not affect the feel after de-blurring.
②Natural pastes, synthetic pastes or composite pastes have their respective focuses, and the properties of pastes, additives, and cosolvents are different from each other. Different types of products and ink sizing prescriptions with different viscosities should also be adjusted instead of the same thing. , Enterprises should adjust various additives such as pastes according to product requirements. This is not only a cost issue, but also directly affects the color density, pattern clarity and finished product feel.
③There are sizing methods
Coating, single-sided rolling, double-sided padding and other methods: whether it is sizing on a conventional stenter or a special sizing machine, many problems have been exposed in actual production at present, such as operation, cost, coiling, quality, weft adjustment, Variety applicability is not compatible, and continuous research and improvement are needed.
3. The relationship between printing machine speed, machine stability and cost
With the continuous advancement of high-speed digital printing machine technology, the printing speed has also continued to increase, reaching a speed of 400~1000m2/h, and it is still improving. High-speed digital is a major development trend in the future.
①The faster the speed, the more high-frequency sprinklers are needed. High-frequency sprinklers are not only expensive, but also easy to damage. They are consumables, and the maintenance cost after operation is quite high. The input-output ratio should be calculated according to your own needs.
②The faster the machine, the higher the requirements for the supply system of electromechanical control, print head working conditions, ink quality, high-speed data processing, sizing semi-product quality, machine maintenance, etc., if there is a problem, the digital machine will not operate normally, especially the print head The more it is, the more maintenance will be done in the future, the operation will be abnormal or the operation rate will not be high, and the cost will be quite high. Stability and reliability are more important than speed.
③Different machines, nozzles, and inks are different, and the types of products are different. Choose the appropriate machine, nozzle, and ink according to the product, and don't be arrogant.
④ Manufacturers should choose machines that suit their needs based on their own company and product positioning. Under the control of reliability and cost budgets in advance, improving production efficiency and printing speed is the way to go.
4. Factors affecting the stability of active digital colors
In the actual production process, color stability is difficult to control, and there are many factors that affect stability:
①There are many ink and print head manufacturers on the market. They use dye matrix structure, additives, strength, and viscosity. In addition to the error of each batch of strength, the ink storage quality is not stable enough, which is also the cause of the color difference. One.
②Digital printing colors are chaotic due to four or eight colors, and they are evenly distributed in dots. Small changes in printing conditions such as voltage, ink temperature and humidity will affect the working status of the print head, which will cause dot-like changes in ink, and ultimately change in color and light. .
③Due to the particularity of digital printing, the choice of ink is limited. Some dye structures determine the stability of dyeing. In addition, the color matching is multi-color dots superimposed on the color, and the changes in the position of the overlapping color are also the reasons for the change of shade. .
④Due to the sizing paste additives, a large amount of ink accumulates on the surface of the cloth, and the continuous printing speed is limited. The unsteamed cloth after printing is easy to absorb moisture, and the upper and lower sides are uneven. The temperature and humidity changes during the steaming process cause the color and light change to be an important reason In the production process, it is necessary to strengthen management for the control of the dry humidity of the cloth surface.
⑤ There are many factors that affect the color stability. Among them, companies must establish their own company's operating procedures for each process, operating standards for on-site management, and record the data of process changes to find the law of change. Strict implementation of the establishment of standard color management is the most important.
5.Pay attention to finishing quality control
As the digital printing cloth surface contains a large amount of dyes, the auxiliary agent can easily absorb a large amount of water during steaming, which causes the temperature and humidity in the steaming machine to change and the color and light changes. In addition, the cloth surface absorbs moisture, and the cloth collides with the cloth during the steaming process, and the friction causes the cloth surface to become colored. This is the difference between digital steaming and conventional printing steaming.
a. Choose a steaming machine suitable for digital products
b. Strictly control the dry humidity of the cloth surface before steaming
c. Master the machine during the steaming process, and the law of normal production temperature and humidity changes
d. Establish and strictly implement measures and systems to prevent printing and color mixing
Digital products contain a large amount of paste and dyes on the cloth surface. It is necessary to quickly swell in the early stage of the washing machine to wash away the alkali agent and unfixed dyes. It is necessary to strengthen the spray washing in the early stage to prevent the later soaping staining. The energy-saving washing machine suitable for small batches and multiple varieties is required by digital.
③ Finishing quality control is very important
Digital printing costs are high, and the added value of finished products is also high. Similarly, customers have high expectations for digital products. Finishing is very important for product quality and added value. Many companies attach importance to the digital printing process and do not pay attention to finishing. They often use the existing production lines of traditional printing factories to produce digital printing. There are some problems. The short-term establishment of a quality tracking assurance system to strengthen quality management may be a low-cost method of post-processing. However, as the industrial-level digital industry gradually expands and improves, qualified enterprises must establish professional and detailed digital Product finishing lines to ensure quality and delivery. The finishing equipment dedicated to digital products should also be refined and upgraded to suit the use of industrial-grade digital products.
6. Cultivate talents
New markets, new technologies and new equipment require a variety of professionals to study, research and improve, and the training of professional teams requires time, funds, and methods. Enterprises must have a long-term development perspective and focus on team training. The healthy growth of the digital printing professional team is the guarantee for the sustainable development of the new enterprise.
Zhengzhou New Century Digital Technology Co., Ltd.,- (Fedar Printer:www.fedar.com.cn)is a high-tech enterprise specializing in research, manufacture, sale and service of sublimation printer，digital textile printer ,inkjet heat transfer printing machine and related consumables.
By cooperating with world famous printhead manufacturers and software suppliers, we integrate exquisite and practical technology into our products. Up to now, fedar printer has independently developed a series of mature products.