Curing of UV inks on inkjet printers

UV curing methods are now widely used by inkjet printers. UV curing ink has three major characteristics: energy-saving drying, a wide range of printability of the substrate, high-speed curing can shorten the follow-up process time. For the UV curing on inkjet printers, in addition to the above characteristics plus the characteristics of digital processing, the manufacturing technology and control technology of inkjet print heads are continuously improving. Now the main applications are:

(1) Printing of variable data such as logos;

(2) Printing of wide-format images with a small number of copies;

(3) Printing of substrates for non-ink-absorbing packaging.

Inkjet printing relies on the printing substrate to absorb the ink to complete the printing, UV inkjet printers rely on the photopolymerization ink to achieve high-speed polymerization and curing to complete the printing. According to such features, UV inkjet printers can adapt to a variety of needs and use digital processing to meet production.

1. Application of UV Curing Technology in Inkjet Printing

The ink-jet method belongs to the real non-contact printing, it has the ink application function to any base material, in order to finish printing, UV solidified ink can improve the insufficient way of the ink-jet way.

1) Marking inkjet printer

UV inks that cure at high speeds without penetrating and evaporating have long been used in marking and other printing because of non-contact. The printed content includes variable data such as product name, batch number, production date, date, bar code, and address, as well as resist patterns and decorative graphics.

The printing presses for the above uses continuous and piezoelectric on demand. Continuous printing has been expanded due to multi-jet printing and multi-colorization. As a UV ink, instead of four-color printing, it uses black, white, yellow, red, and so on, centered on spot colors.

2) Graphics Printing Machine
UV ink jet printers for graphics use four-color overprinting to achieve high image quality using pigment inks with excellent adhesion and adhesion. UV inkjet printers for graphic printing were introduced in 2000. For this type of application, owing to its large area, screen printing or electrostatic printing has been the main method in the past, and POP applications such as large-area billboards, wallpapers, shop signs, hanging screens, interior decorations, etc. Due to the small number of printing parts, the restrictions on the ink and the substrate are small, so the advantages of UV ink jet can be exerted.

Oil-based inks can cause environmental pollution due to volatilization of solvents, coupled with the constraints of various plastic printing materials, and UV is able to overcome the above two points and change as soon as possible. The biggest contradiction is to deal with large-scale printing materials, such as soft or hard plastic, non-woven fabrics, polyethylene, fabrics, synthetic paper and so on. Take UV inks, in order to get the best picture quality, different materials should use the corresponding ink.

The print head is fixed, and a high-speed graphic printer is now available by means of high-speed transfer of the printed substrate. According to the assembly of the print head and the lamp, the arbitrariness of the printed web is obvious. The use of package printing for sample and test sales, or the application of similar screen printing, and the combination printing with offset printing are being gradually applied.

The use of multi-color narrow-width printing presses has been popularized in the printing of non-ink-absorbing materials such as CDs, card products, and trademarks. Since the types of substrates are limited, it is important to adapt to a wide range of inks.

2. The composition and printing of hardware

The hardware is based on the consideration of the movable part and the fixed part, and the printing method is different.

(1) The position accuracy of the printing substrate is large and the movement distance is long;

(2) Synchronization of ink application and UV irradiation;

(3) the sequence and quality of each ink application;

(4) Distance adjustment of printing substrate and printing head;

(5) Printing speed.

Most printers set a variety of substrates in advance to improve arbitrariness and extension.

1) Configuration of print heads and lamps
For wide-width printing, the irradiation device adopts a structure that works in conjunction with the print head in consideration of the curing time. The drawing head and the lamp configuration are different for the drawing-type operation and the printing-type operation. For the drum feed type, various configurations can be made on the printing substrate to be moved on the drum.

From the point of view of the printing process, there are a method of printing a single-color after-curing and a method of sequentially irradiating with the printed full-color ink, and a method of performing a curing treatment after printing a full color, etc., and the selection of it depends on the printing activity. Depends on the item.

2) Print head

The print heads on UV ink jet printers have until now been effective continuous types and piezoelectric types capable of designing a wide range of ink tolerances.

Because of the high viscosity range of the UV ink, the particle formation performance must be noted that the drive frequency used, the droplet volume of the target, the ejection speed, etc. must be adjusted at any time. The stability and quality of the main drop, follow-up suppression are important. This kind of control does not need much to say about the printing of the picture, have very high value to the circuit. In order to increase the printing speed, a large number of print heads are often mounted, so the drive mode of the accumulation mode is very important.