Analyze the three main aspects of improving the quality of digital printing
- Issue Time
Printing precision is mentioned, we will always ask how much is the digital printing resolution, it is 1440 dpi or 720 dpi, actually it's just part of the printing accuracy, which will involve the nozzle resolution, mechanical precision (step precision and mechanical precision roller shaft), ink and the matching degree of the three main aspects of nozzle.
1. Accuracy of sprinkler head
At present, there are piezoelectric nozzle, thermal foaming nozzle on the market, photo head, industrial nozzle. Among them, the most commonly used printing nozzles are piezoelectric photo nozzles and industrial nozzles. Piezoelectric photo head with EPSON four - generation head, five - generation head, six - generation head. The five-generation head is a mainstream product with a maximum resolution of 1440dpi, which supports the printing mode of 720dpi and 540dpi. In addition, some manufacturers, such as SPETRA, ricoh and KYOCERA of the United States, choose industrial nozzles with a general resolution of about 720dpi. Compared with EPSON nozzle, the cost is high, but the service life is long, the resolution is low and the ink drops are large. However, from the perspective of textile printing, it is difficult to distinguish the above resolution of 720dpi from the visual effect due to the coarse fiber of the fabric. From the nozzle Angle, nozzle due to technology is dominated by a handful of factory, printing machine manufacturer from these manufacturers purchase, so, in fact, if choose machine printing precision, you basically is the same as the starting point of nozzle.
2. Mechanical accuracy
The effect on printing is actually much greater than the resolution of the nozzle because mechanical processing is not very high in the domestic level. Generally, the length of the printing machine is between 1600mm and 2200mm, and the length of the shaft roller is generally between 2200mm and 2800mm. Direct injection with Italy MS conduction band type printing, for example, shaft diameter of 400 mm, length is 2200 mm, shaft diameter, concentricity, straightness and other comprehensive error is 0.003 mm, namely printing mechanical error of a perimeter is 0.01 mm, the difficulty of processing a such axis. But the same, we can also imagine, if a company product error is 0.1 mm in diameter, then in the process of printing, nozzle in the two connection parts of the inkjet, a side that there might be a cross, but on the other side has a 0.3 mm of the white line, this is no customer can accept; Similarly, if there is a problem with concentricity and straightness, the situation is similar.
The assembly precision is not enough, which is also the main reason that affects the mechanical precision of printing. For example, the lack of parallelism, resulting in the fabric run off, bearing quality is not satisfactory, wear is not consistent, will also affect the problem of parallelism.
It is generally believed that ink may affect color saturation, color fastness and coloring, but in fact, ink can also have a great impact on printing precision. It is obvious that if the ink is not smooth enough and there are many mechanical impurities, it may break the line and block the head. In the process of printing, small white lines will appear, which will affect the precision of printing. If the ink viscosity, surface tension and other parameters appear problems, may cause oblique spray. Moreover, the preservation stability of ink, the unity between the upper and lower batches of products and so on are the main causes of quality problems.
To sum up, we're going to get a good printing quality, get a good printing precision, not only focus on the resolution of the nozzle, the mechanical precision, matching the quality of the ink is also very important.