Requirements for digital printing inks

The key to digital printing is ink. Inkjet inks must meet certain physical and chemical standards and have specific properties to form droplets. They are suitable for specific inkjet printing systems and provide excellent image and color vividness. The performance of the ink not only determines the effect of the printed product, but also determines the shape characteristics of the droplets ejected from the nozzle and the stability of the printing system.

The basic performance requirements for reactive dye inkjet printing inks are as follows:

Surface tension

The effect of surface tension on ink drop formation and print quality is extremely significant.

From the observation of the presence or absence of spillage around the nozzle during the inkjet test, the length of the droplet breakage, the stability, the droplet velocity, and whether it is running in a straight line, the quality of the droplet formation can be evaluated, all of which are subject to surface tension and viscosity. influences.

Too high surface tension makes the print head surface not easy to be wetted, the ink is not easy to form small droplets, and may have a long break length, or break into a “tailing” shaped droplet, and the ink build-up around the nozzle will affect the fineness. The linear operation of the droplets and the reproducibility of the printing effect.

If the surface tension is too low, the droplets will be unstable and even form a “satellite”, creating a sputtering spot. It is generally required that the surface tension of the inkjet ink is lower than that of the printed substrate, and the contact angle of the ink droplet with the substrate is greater than 140 degrees to obtain a clear pattern.

In summary, a suitable surface tension requirement is that the ink can be easily infiltrated into the interior of the fabric without causing percolation of the ink droplets on the surface of the fabric, and also needs to be tailored to the equipment used.

Viscosity

As previously mentioned, the viscosity of the ink, together with the surface tension, affects the formation of ink droplets.

The high viscosity causes the broken tail to be stretched and drawn in a draw shape; if the viscosity is too low, the droplets are easily broken.

Another important parameter that is affected by viscosity is the jet velocity of the droplets. If the viscosity is too high, the droplet velocity will decrease and even the ink droplets will not hit the same point on the substrate being printed.

Basic tests and actual printing results have shown that a viscosity of less than 10 mPa·s (preferably 2 to 4 mPs·s) is a suitable range for obtaining a satisfactory droplet shape and printing effect.

 Conductivity

In continuous jet printing equipment, the ink droplets are deflected by the charge, so the ink must have the ability to be charged and electrically conductive.

The ORIC printing machine requires an ink conductivity of 750 siemens or more.

In fact, as an aqueous ink system, it has good electrical conductivity. It is only necessary to add a special conductivity modifier in a solvent-based ink system. Studies have shown that the effect of conductivity on droplet formation has not found a significant dependence.

PH value

The pH of the heat transfer ink should be stable. Some dyes will precipitate due to changes in pH. Generally, the pH should be adjusted at 7~8. The ink is acidic and will corrode the nozzle and metal parts. A suitable pH value facilitates the combination of dye and fiber reaction and promotes print clarity.

There are other technical requirements for inkjet printing inks, such as good dyeability, so that the color of the fabric is high; the purity of the dye is high, so as to ensure the vividness of the color; the thermal stability and the frost resistance are good, so that the storage Stability can be improved.

How to grasp the accuracy of digital printing?

The application of digital printing has brought convenience to people’s daily life production. The popularity of digital printing has brought a development opportunity for textile printing and dyeing. Let’s take a look at the knowledge about digital printing precision.

Users of printing equipment often pay attention to the printing precision of digital printing equipment, equipment stability, ease of operation, ease of maintenance, adaptability, and cost of use. When it comes to printing precision, people always think of the printing resolution, which is 1440dpi or 720dpi. In fact, this is only part of the printing precision. Printing accuracy will involve many aspects, such as nozzle resolution and mechanical precision (stepping). Accuracy, mechanical accuracy of the shaft roller, matching of ink and print head, etc.

1. Print head accuracy

At present, the nozzles on the market include piezoelectric nozzles, thermal foaming nozzles, photo nozzles, and industrial nozzles. Among them, the nozzles commonly used for printing are piezoelectric photo nozzles and industrial nozzles, and the piezoelectric photo nozzles are EPSON four generations. The fifth generation and the sixth generation are the main products. The fifth generation is the mainstream product. The higher resolution is 1440dpi, which supports 720dpi and 540dpi printing mode. This is also the nozzle used by the printing machine. In addition, some manufacturers choose industrial nozzles, such as the US SPETRA, Japan Ricoh, Japan Kyocera, etc., the industrial head general resolution is about 720dpi. Compared with the EPSON nozzle, the industrial head has a high price, but has a long service life, low resolution and large ink droplets. However, from the perspective of textile printing, the fabric is relatively thick, and the resolution above 720 dpi is visually It is difficult to distinguish. From the point of view of the nozzle, since the nozzle technology is monopolized by a few manufacturers, the printer manufacturers are purchasing from these manufacturers. Therefore, if the precision of the machine printing is selected, the starting point of the nozzle is basically the same.

2. Mechanical precision

The impact of machinery on printing is actually much larger than the resolution of the nozzle, because machining has always been a short board in the domestic processing industry. The width of the general printing machine is 1600~2200mm, and the length of the shaft roller is generally 2200~2800mm. Take the Italian MS belt-type direct-injection printing machine as an example, the shaft diameter is 400mm, the length is 2200mm, the comprehensive error of shaft diameter, concentricity and straightness is 0.003mm, that is, the mechanical error of printing one circumference is 0.01mm, processing one The difficulty of such an axis can be imagined. But in the same way, if a company’s product diameter error is 0.1mm, then during the printing process, the nozzle may have a cross on one side of the two inkjet joints, and a 0.3mm white line appears on the other side. It is unacceptable to any customer. By analogy, if there is a problem with concentricity and straight digital printing, the consequences are similar. The assembly accuracy is not enough, which is also the main reason that affects the precision of printing machinery. For example, the parallelism is not enough, causing the fabric to run off, the bearing quality is not close, and the wear is inconsistent, which will also affect the parallelism. Servo motors and control systems, in addition to individual small products, generally use the products of international brands in the industry, which has little effect on mechanical precision.

3. Ink aspect

It is generally believed that ink may affect color saturation, color fastness, and amount of coloration, but in fact, ink has a great influence on printing accuracy. Obviously, if the fluency of the ink is not good and there are many mechanical impurities, there may be disconnection and plugging, and small white lines appear in the printing process, which affects the precision of the printing. If there is a problem with the parameters such as viscosity and surface tension of the ink, it may cause oblique spray. Then there is the preservation stability of the ink, the uniformity between the batch and the batch, etc., which are the main reasons for the quality of the printing.

In summary, we need to obtain a good print quality, get a good printing accuracy, not only focus on the resolution of the nozzle, mechanical precision, the quality of the optional ink is also very important.

Five Reasons for Burning Print Head of Digital Printing Machine

The digital printing machine print head can be used to print the best results, and the print head is good, and the ink will be more expressive. The print head is an indispensable carrier for digital printing production, but the operation is not good, the print head is easy to be burned, then everyone knows why the digital print print head is burnt?

There are five reasons why the digital printing machine print head is burnt:

1. The static electricity is too high

Excessive static electricity can affect the printing effect. In severe cases, it can damage the circuit part of the printer. Especially in the autumn and winter seasons, if the human body is too high, if you touch the print head directly, it will easily damage the circuit part of the print head. Therefore, not only the printer has a good and stable grounding, but also the operator is in contact with the machine and the print head. Be sure to do anti-static measures, such as with anti-static meters.

2. The positive and negative poles of the power supply are reversed.

This kind of operation is illegal. During the operation, try to follow the standard operation, especially the print head of the wide-format digital printing machine. If it is not necessary, try not to insert or pull the circuit to avoid the positive and negative connection of the power supply. Reverse operation.

3. Staying in the “dry burning” state for a long time

If the print head of the digital printing machine is in a “dry burning” state for a long time, it is naturally easy to be burned.

4. The working voltage is too high

If the print head is operated under high load for a long time, it is easy to cause aging of the piezoelectric crystal, especially for the piezoelectric print head.

5. Strong corrosive ink or other liquid gets on the printed circuit board

How to get strong corrosive ink or other liquid on the circuit board of the print head can easily cause short circuit, especially solvent ink. Therefore, in the process of processing the print head, we need to pay special attention to not to blot the ink onto the data line interface of the print head, which is likely to cause a short circuit. In severe cases, the print head will be burnt.

The above 5 points are the reason why the digital printing print head is burned, I hope to help you digital printing practitioners.

In the daily production of digital printing, everyone should pay more attention to the maintenance of the print head. If the print head is burned, there is usually no way to recover it. It can only be scrapped and replaced with the print head. This increases the production cost.

How to better use eco solvent ink?

Because of the characteristics of eco solvent ink, the selection of continuous supply should be very careful. Eco solvent ink can be coat-free printing on some materials, or can be coat-free by means of printer heating, but for some smooth surfaces, ink alone is powerless, ink will accumulate together, and can not be clearly imaged.

Then it is necessary to use special coating solution in combination with the three advantages of using coating:

1. The drying speed is fast. The coating is prepared with special chemical raw materials and used with eco solvent ink. It will dry within one minute after printing, especially in the smoother materials such as glass.

2. Printing quality is not good. Direct printing with coatings on some materials, mainly smooth and non-absorbent materials, has poor effect, and the effect is extraordinary after using coatings.

3. Wear resistance and waterproofing because of the binder ingredients in the coating ingredients, so after printing, the ink and material absorb very closely, far more than the wear resistance without coating. Eco solvent ink has some advantages of all kinds of ink, and it is a product with wide application. But it is irresponsible for some manufacturers to say that this kind of ink is superb. Good ink also needs correct methods to use. Details can not be careless. Only in this way can we use this kind of ink well and let this kind of ink create the greatest value for you.

 

Four Manufacturing Methods of Customized T-shirts

If you’re considering purchasing custom made shirts for an event or a team, you should understand the possible methods used to get what you want. With computer technology adding to the older existing methods, you now have many choices. Which type will work best will depend upon several factors, including what you want done and which method a professional printing company like ORIC offers.

Creating Custom Made Shirts: Silk Screening or Printing

This is by far the most common way used to create custom made shirts, and it’s perfect if your design only requires a couple of different colors. It is also for those who want their design or lettering to have a raised feel and appearance. The advantages of this method for any producer include speed and cost-effectiveness. You will be wowed by the durability of the imprinted designs, as well as the vivid colors.

Embroidery

If you have a dress, shirt, hat or jacket on which you want to place a specific image or lettering, companies such as ORIC suggest a technique called embroidery. This is either done by hand, or by using a specific machine. T-shirts may pucker as a result of the process, which may limit the bulk production of custom-made shirts. The cost is also a factor in reducing its overall popularity.
Nevertheless, if you want something embroidered, it can be done. Simply stick to smaller designs. Alternatively, ask whether you can combine this method with silk screening to achieve a unique design.

Digital Printing

Technology has resulted in many advancements in printing. Among them is the now common Direct-To-Garment (DTG) digital printing. It is subdivided into two types:

  • Dark Direct to Garment Printing: This is an expensive form of DTG printing, and a variation on light DTG digital printing. It can successfully achieve a colorful image on a black t-shirt without the use of appliqués or iron-ons.
  • Light Direct to Garment Printing: It does not use white ink, and it is best if you choose light colored custom made shirts. The color choices are amazing and very numerous.

Unlike with a few other methods, DTG custom made shirts do not crack or peel as time passes. The ink remains solid as it is embedded into the fabric of the shirt.

Heat Transfers

If you have an image in mind, one that is readily and commercially available, one of the more common methods to transfer it to custom made shirts is through heat transfers. Heat and pressure are the basic requirements to successfully transfer the image. If this is a method you’d prefer, first make sure you or your company chooses an expert in the field. The results can vary, and you could get crooked images and wrinkled t-shirts resulting from someone who is less than professional.

If you’re planning on a single design, or want to create a uniform look for a group by applying a log or image to custom made shirts, consider and weight your options. Be sure to talk to someone who knows the different methods, such as the professionals at ORIC. Listen clearly to what is said, do your own research, and only then go ahead with your plans.