The printhead is a key core component of inkjet printing equipment and plays an important role in printing quality and speed. The printheads used in China's digital inkjet printing of textiles are basically imported, and the main suppliers include Kyocera, Fuji, Ricoh, Epson, Seiko, Xaar, Konica Minolta, Brother, etc.

In the past two years, the printheads have been optimized and improved in terms of improving production efficiency, improving printing quality, and extending service life. For example, the internal circulation function of inkjet ink has been continuously improved, which is not easy to cause blockage and extend the life of the printhead. The upgrade of printhead materials, glue and other materials has better compatibility with digital printing ink and significantly improved corrosion resistance. The surface coating protection technology of the printhead supports multiple types of inks. It can meet the high drop printing function, and does not fly ink when the spray distance is far, so as to achieve accurate printing and good penetration effect, especially suitable for printing of heavy fabrics, velvet fabrics and uneven fabrics.

The 58 digital inkjet printers exhibited at the 2022 China International Textile Machinery Exhibition and ITMA Asia are equipped with printheads made in Japan. Compared with the previous exhibition, Epson printheads rose to the first place, with 30 digital printers applied, accounting for 51.8% of the exhibited equipment; Kyocera printheads are applied on 16 devices, and the proportion dropped from 51% in the previous exhibition to 27.6%; this exhibition also exhibited equipment with Brother printheads and Xaar printheads.

1. Main Suppliers of Printheads and Product Features

Kyocera has developed a new printhead model KJ4B-EX600-RC, which uses an integrated piezoelectric brake to improve the change of concentration value and improve the accuracy of inkjet placement. The internal circulation technology of the printhead adopts an ink circulation system with pressure control to form an auxiliary circulation flow path near the direct way to nozzle hole, which ensures uniform ink temperature while avoiding drying and ink precipitation at the nozzle. It is particularly suitable for high-concentration, easy-to-precipitate and fast-drying inks. The printhead is also equipped with a water-cooling structure to improve the stability of continuous, high-speed, high-quality printing and eliminate the phenomenon of ink precipitation and clogging.

Since Epson officially started selling printheads to the China market in 2019, its products have been widely used in the digital inkjet printing industry with their advantages such as fine patterns, stable and reliable performance, and high cost performance. Among them, the I3200 and S3200 series of printheads are the most popular. It can be seen from the exhibition of the 2022 International Textile Machinery Exhibition that more than 50% of the exhibited equipment is equipped with Epson series printheads. S3200-A1 and S3200-A3 are two industrial-grade printheads from Epson. The S3200-A1 printhead is mainly suitable for digital transfer printing on polyester fabrics. Compared with the S3200-A1 printhead, the S3200-A3 printhead adopts an easily expandable S-shaped design and a sturdy structure, therefore, it can spray ink droplets with larger volume and better permeability, making it more suitable for direct printing on textile fabrics.

Fujifilm Samba printheads also have an internal circulation function, which ensures stability during the spraying process through dual circulation inside the printhead and directly to the surface of each nozzle hole. The overall silicon microelectromechanical Si-MEMS structure has good ink compatibility and strong corrosion resistance. During the 2024 Drupa Exhibition in Germany, Fujifilm Dimatix launched a new printhead for textile printing - SkyFire® SF600 inkjet printhead (Aurora SF600), with a print width of 65mm, a resolution of 600dpi, and an ink drop range of 5 to 25pL. The printhead can spray 12g of ink per square meter per color on high-speed equipment, and has better penetration effect on high-count, heavy or velvet fabrics, and can also meet the high-speed operation mode of Single Pass printing equipment.

Ricoh has not launched any new printheads for digital inkjet printing of textiles in the past two years, and the main products are MH5320 and TH6310F. The MH5320 printhead is made of all-steel material, which is not easy to clog and corrode, and has strong durability; TH6310F is a thin-film piezoelectric nozzle, which is the one with the highest production capacity in all Ricoh industrial inkjet printing printheads. The special nozzle position laying mode reduces the impact of airflow during the flight of ink droplets, and can meet the requirements of high-drop printing (4mm nozzle distance to fabric). Both MH5320 and TH6310F printheads have been relatively maturely applied in the field of digital direct printing.

2. R&D Progress of China Digital Inkjet Printing Printheads

The manufacturing technology of piezoelectric inkjet printheads involves piezoelectric ceramic materials, high-quality adhesives, micro-electromechanical system manufacturing and other fields, and is a typical high-precision product. The key points of the research on piezoelectric inkjet printheads are their design principles and methods, the design and manufacture of piezoelectric drive structures and drive systems, the development of piezoelectric inkjet printhead sealing materials, and the development of inkjet printhead sealing process. At present, it is still a very hard technology that restricts the development of the industry and is included in the "Industrial Basic Innovation and Development Catalog".

Some domestic companies have carried out the research and development of piezoelectric inkjet printheads, but they are currently only in the experimental verification stage and have not yet been mass-produced for industrialization. The domestic piezoelectric printheads developed by Zhongkang Jihong Technology Development Co., Ltd. have a resolution of 360dpi, a maximum drive frequency of 7.8~30kHz, an ink droplet size of 13~35pL, and a number of nozzles of 512~1024. They are currently in the research and development and industrialization verification stage. ASKA Co., Ltd. continues to focus on the research and development of piezoelectric inkjet printheads, and has developed two printheads that support water-based inks, namely LYNX1024 and LYNX512. The LYNX512 has a resolution of 200dpi, a maximum spraying frequency of 25kHz, and an ink drop range of 55 to 90pL; the LYNX1024 has a resolution of 400dpi, a maximum spraying frequency of 40kHz, and an ink drop range of 18 to 25pL. Both LYNX1024 and LYNX512 are equipped with an ink circulation system. In addition, Hangzhou Honghua and other companies are researching and developing printheads suitable for digital inkjet technology. 

As the core component of digital inkjet printing, the research and development of domestic printheads plays an important supporting role in improving the resilience and security level of the supply chain of the digital inkjet printing industry. At present, although domestic printheads have made certain progress, there is still a big gap compared with the advanced level of foreign countries. It is urgent to carry out joint research on the hard technical bottlenecks to promote the competitiveness of China's digital inkjet printing industry.