Negative ink supply VS Positive ink  supply system, which is better?

What is the negative pressure ink supply system of a UV printer?

When the ink in the printhead and ink outlet tube is attracted by the negative pressure air, the ink can maintain a balanced state without falling off, when the printhead prints downward, it can automatically draw ink and replenish it, achieve the function of continuous printing, this is the working principle of the negative pressure system of uv flatbed printer.

Analysis of the mainstream ink supply systems and advantages and disadvantages of the UV flatbed printer industry:

Positive pressure ink supply:

The ink bag is installed directly on the machine head and is higher than the print head position. directly utilize the height difference between the ink bag/ ink tank and the print head, the weight of the ink itself to achieve natural ink discharge. It is commonly used by small and medium-sized UV printers in the industry. The system is simple, no secondary ink bag/ink tank, no negative pressure device, lower cost, If the machine configuration  and the assembly quality is not good, ink breakage, ink dripping and other failures are prone to occur during the printing process.

White color independent double-ways negative pressure intelligent ink supply system: 

An intelligent continuous ink supply system that combines intelligent control software with a negative pressure ink supply device. based on the unique ink consistency of white color ink, ink drop weights are intelligently matched to more accurate independent negative pressure values for white and color inks, through the negative pressure bottle, the ink in the main ink bag/ink tank passes through the secondary cartridge and then to the print head, which is the entire continuous ink supply process.

Advantages of white color independent double negative pressure intelligent continuous ink supply system:

During the ink supply process, the negative pressure device always maintains a balanced negative pressure value for the ink droplets, make the ink more uniform and continue to supply ink to the printhead without being interfered by the viscosity of the ink itself and the external environment. The ink supply process is smoother, there will be no problems such as print head broken ink or ink dripping. It reduces consumables waste, printing materials waste, labor waste and is more energy-saving; the ink droplets are uniform and stable, and the printing is more precise. The white ink independent double negative pressure system of uv flatbed printer has main ink cartridge and secondary cartridge. The ink path is: ink is pumped from the main ink cartridge to the secondary cartridge and then to the print head.

Secondary cartridge

The ink on the secondary ink is affected by gravity. so under normal circumstances, the ink will automatically flow to the print head. Therefore, a negative pressure system was added to the secondary ink cartridge, the ink gravity of negative pressure pulling and secondary ink cartridges reaches a balance. The principle is the same as the needle tube,during the printing process, the ink of the second -level ink cartridge is constantly decreasing, then the negative voltage value must be relatively reduced to reach balance. There are two values here are critical:

The response time of the negative pressure system

The switch that controls the changes in the negative pressure system is the solenoid valve. So if the solenoid valve is not used well, its response time is too long, or the response time is not sensitive, Then it has a great impact on the stability of the UV printer. At present, the response time of the solenoid valve used by printer manufacturers is generally 2.5 milliseconds. In order to be equipment more stable, the solenoid valve we use is 1.5 milliseconds.

Pressure resolution

Pressure resolution is to measure the negative pressure system and the second -level ink box ink real the error value between balance. The higher the pressure resolution, the more stable it is for the device.

If the negative pressure is too small, the ink gravity of the second -level ink cartridge is greater than the suction of negative pressure, such a phenomenon will appear on the surface of the print head, which is called an infiltration ink.

If this phenomenon often occurs, generally, it is impossible to print, need to be adjusted. If this phenomenon often occurs, It will damage the spray life more.

If the negative pressure is too large, the gravity of the second -level ink ink is less than the suction power generated by negative pressure, this phenomenon will appear on the surface of the print head, this is called inverted. This phenomenon ink is generally not printed, you need to adjust the negative voltage value. If this phenomenon often occurs, then the scrap rate of the product is very high.

The Giftec UV printer series can currently configure the minimum size of the negative pressure system from 40x62cm, 60x90cm, to 1.2*1.3m, etc. If you don’t know how to choose a printer that suits you, welcome to contact Giftec team to provide you with the best solution. Whether it is end-users or dealers, Giftec team has a suitable solution.