Application characteristics and printing technology of latex water-based ink

Previously, we could easily select the right inkjet technology for large-format and super-large-format printing: when you use an entry-level large-format printer, you can choose water-based inks for it; when you use a printing format that is larger and faster When you have a fast, advanced printer, you can choose solvent-based inks for it. This problem has become complicated because of the advent of UV-cured flatbed printers, followed by the large-scale use of low-solvent inks, including environmentally friendly inks, lightweight solvent inks, or mild solvent inks.
Therefore, when the application of UV technology gradually expands from flatbed printers to roll-to-roll printers, the boundaries between various inkjet technologies are less obvious. Once the high-end system is mature, people who use it will become more and more, and its price will continue to decline.

At the drupa printing exhibition recently held, Hewlett-Packard has introduced a brand new Latex water-based ink printing technology, this more environmentally friendly ink technology will shake up the dominance of solvent-based inks in the market. Hewlett-Packard said that this is an environmental technology, mainly based on the following reasons: It can not only reduce the impact of print production on the environment, but also can improve the operating environment of the operator and the printed product application environment.

The most outstanding feature of the new Latex water-based ink printing technology is that it not only prints on such common substrates as other solvent-based inks, but also in applications where solvent-based technologies are not very good, such as high-density polyethylene. Printing - plays an important role. In addition, this ink can also be recycled.

Hewlett-Packard's senior ink expert Phillip Cagle said: "We have developed a lot of recyclable substrates. If you want to use environmentally friendly ink for printing, then you must throw away all the things printed on PVC."

According to Cagle, in 2007, the total output of the large-format PVC banner printing market in the world was 695,154 tons or 1.6 billion square meters - these materials are sufficient to cover all major cities in the world. The problem now is not the production itself - there is no ink and substrate dealer willing to lose this opportunity to seize market share - but rather how to make these prints to play the most role.

Substitute sheet

Gianluigi Rankin, global PSP manager for HP's wide format substrates, said: “A lot of large format PVC banners will eventually be sent to landfills. If all the banners are to be processed in the garbage dump, they will occupy 592,704 cubic meters of space. Rice.” Rankin did not recommend that the printing plant step up to stop using PVC, but it could slowly replace these materials with more environmentally friendly substrates.

Rankin said: "We have both PVC and other alternative substrates, including HDPE, which is a plastic that can be recycled. Compared with vinyl, printing on HDPE and Tyvek seems to be more difficult, so We must do a surface treatment of these materials, and to be precise, this kind of treatment is not a coating, because the coating will inevitably increase the production cost of the substrate.Of course, the cost we discuss is limited to the scope of digital printing. ”

Although HDPE is recyclable, because latex inks need to be firmly bonded to the substrate, you cannot recycle them like recycled paper (you can't recover to white), but you can use these materials to produce them. Comes to other colored plastic products. In addition, they can also be sent to factories that “turn waste into energy” because HDPE has twice the energy content of coal. Even if it is sent to the dump, HDPE will not damage the environment like PVC.

For printers, because latex-based water-based inks do not emit VOCs during the printing process, they do not need to install solvent extraction systems and do not smell pungent solvent odors - this is not only for the operator of the equipment. The benefits, but also allows them to produce products that are not suitable for printing with solvent-based inks.

Green technology

Cagle said: "The ink is odorless - all the smell you smell on the proofs comes from the substrate, not the ink itself. The pungent odor of the solvent will make you restless."

Hewlett-Packard Company is very concerned about the environmental protection details of the ink system. They designed a cardboard box that resembles a wine box for the ink contained in self-adhesive plastic bags, thereby greatly improving the recycling rate of packaging materials.

Interestingly, latex ink technology was developed by Hewlett-Packard before it entered the large-format printing market. When R&D began, the company had only two technologies, water-based inks and thermal printheads (all of them used on the Designjet press). Prior to the acquisition of companies such as Angelica, ColorSpan, and Nur, HP's goal was to develop an industrial-grade printer with its own technology.

However, even if the above companies were acquired, Hewlett-Packard still put latex ink on the market. Like HP's Inkjet Web Press concept printer, this product has become the focus of Drupa's attention. It has proved to people that it was innumerable. Thermal printhead technology used on desktop printers can also be used on industrial-grade printing equipment.

According to Cagle, there are two reasons why latex water-based ink technology is highly sought after: price and performance. He said: “It uses the same thermal print head as a desktop printer, so it can increase production speeds to twice that of similar products (similar in price).”

Hewlett-Packard's first product to use latex ink is Designjet LC65500, which has a print width and price of 2.64 meters and 90,000 euros, respectively. This six-color printer can print 70 square meters/hour and 35 square meters/hour when printing outdoor and indoor images. So far, HP has not yet developed other models based on latex ink, but this technology can already be applied to the roll-to-roll printing process. The company believes that UV inks are still the best choice for platform printers.

Hewlett-Packard has been trying hard to solve the problem that the thermal print head's service life is not as long as the piezoelectric print head. Cagle said: “We have extended the life of the printheads. Although we have not yet obtained accurate data, we hope that these printheads can eject 50 liters of ink.” When we began to worry about replacing the printheads, which would increase production costs, Cagle This brings us good news. He said: “Latex water-based inks cost about as much as light solvent inks. Of course, this cost also includes print head replacement costs.”

Latex inks seem to be a very interesting technology that can help large-format printers solve many problems encountered in the purchase of a new generation of printing equipment, such as: cost, ease of use, application range, durability and environmental protection Performance and so on. Hewlett-Packard's only concern is the market prospect of this product, but Cagle is not worried about this, because he believes this technology just proves the company's creativity.

He said: "Latex ink is unique in the market. Before, people were just talking about latex ink, but they were not used in actual production, because it is a difficult technology for manufacturers. But once they are produced by manufacturers, they become very reliable and very easy to use."

Inkjet technology opens up to colloidal

HP is not the only company that has developed new large format imaging technology. Earlier this year, Océ also introduced its innovative imaging technology, CrystalPoint.

CrystalPoint technology combines the advantages of toner and inkjet technology to produce monochrome and color waterproof documents for large-format printing applications. On May 14, Océ demonstrated the first device using this new technology - the Océ ColorWave600.
The CrystalPoint process uses microsphere toner, which Océ calls TonerPearls. This toner can be converted into a gel. The toner glue is then printed on the paper surface in an ink-jet manner, including recycled paper and uncoated paper. The effect of printing is half-light, and the image does not change with water.

Océ ColorWave 600 focuses on two customer groups: one is CAD design printing for architecture, engineering, and civil engineering; the other is printing of retail posters and store promotion advertisements. The Océ ColorWave 600 can output a sheet of A0 in half an minute in economic mode, and only 3 minutes in high quality mode.

Neil Westhof, international product manager for Océ large-format printing systems, said that the trend in large-format color printing is now “the boundaries of application are becoming increasingly blurred”. He believes that this brings about a new growth in equipment demand, especially when the equipment “can be used for high-quality, fine-line printing, and can be used for rough printing such as poster printing”.

Océ also stated that CrystalPoint technology is a product that “has a completely sustainable concept” because TonerPearls colloidal toner used in this technology is printed in an ink jet manner without producing ozone or odors. In addition, the semi-finish technology used in this device can also meet the paper coating requirements.