Abstract: China is a globally recognized major producer of ceramic building materials, accounting for 65% of global output. However, due to outdated printing equipment and technology, its products are only positioned at the low to mid-range level. Furthermore, high energy consumption, high pollution, and high emissions hinder the development of China's ceramic building materials industry. Inkjet printing technology offers advantages such as low energy consumption, high efficiency, and high-quality printed products. Its introduction and development will undoubtedly provide strong technical support for China's progress towards becoming a leading ceramic building materials producer.
Keywords: ceramic tiles, ceramic ceramics, screen printing, roller printing, inkjet printing
Inkjet printing--The revolution of printing technology in tile industry
HUANG Feng-ge
(Shanghai Teckwin Development Co., Ltd Songjiang Shanghai 201601)
Abstract: Tile production in China is much more than 65% all over the world which is considered as the biggest one. Somehow as the production equipment and printing technology is dropped behind, the tiles which made in China are located as the middle or low levels' products. Meanwhile the current situation such as high energy consumption, high pollution and high emission also frustrated the development of Chinese tile industry. Inkjet printing technology with its advantages in low energy consumption, high efficiency, good quality printing and etc., the introduction and development of this technology will provide the strong technical support to lead Chinese tile manufacturing from quantity to quality.
Keywords: Tile industry Tiles Screen printing Rotary printing Inkjet printing
Current Status and Problems of Ceramic Foil Printing Technology
China is a major ceramic producer, and building ceramic products such as wall tiles and floor tiles are an integral part of people's lives. With the rapid development of China's economy, especially the real estate industry, people's demand for building ceramic products is constantly increasing. In the past decade, the growth rate of China's building ceramic production has exceeded 10% annually. In 2010, China's building ceramic output value accounted for 1.2% of the total GDP, its output accounted for 65% of the global total, and its exports accounted for more than 25% of the global output.
The main production process of ceramic tiles is as follows: material preparation – pressing and molding – drying – glazing and printing – firing – polishing/waxing. Among these, the glazing and printing process (i.e., the printing process) is crucial in the production of pre-kiln colored ceramic tiles. Its process and methods largely determine factors such as raw material consumption rate, yield rate, product quality, production cost, energy consumption, pollution, and emissions. Printing technology, as the core of ceramic production, has gone through two major technological periods: screen printing and roller printing.
Screen printing, a type of stencil printing, is one of the four major printing methods along with offset printing, letterpress printing, and gravure printing. Its principle is to transfer ink through the perforations of a stencil onto the substrate under pressure, creating a pattern or text identical to the original artwork. Screen printing is a major invention of my country, with a history of over two thousand years. It was once widely used for printing on paper, fabrics, leather, metal, and plastics, becoming a primary process for design, decoration, art, and advertising. In the 1970s, with the rise of the modern ceramic tile industry in my country, flatbed screen printing began to attract widespread attention. However, the first mechanized and automated screen printing equipment used on my country's ceramic tile glazing lines was imported from Italy. It wasn't until the 1980s that domestic production of such flatbed screen printing machines was achieved, leading to the emergence of companies like Meijia, Xiwang, and Weisheng, and the widespread adoption of flatbed screen printing technology.
Screen printing has the advantages of simple plate making, convenient operation and strong adaptability. However, since screen printing is a planar transfer printing, it is limited in printing on uneven brick surfaces, making it difficult to achieve diversified and three-dimensional effects, and the printing efficiency is also low.
Compared to screen printing, roller printing is a flexible printing method. Its breakthrough lies in its ability to print on surfaces with varying textures, resulting in richer surface layers and a higher degree of natural simulation. The principle involves the continuous rotation of multiple rollers coated with different colors to create color printing on the tile surface, thus improving the production efficiency of the printing process. The emergence of roller printing technology can be considered a major advancement in tile printing technology. It is said that the Italian company Sifael began using this technology in the mid-20th century and applied for patents in many countries and regions worldwide, obtaining a patent in China in 1999. Today, this roller printing equipment is used by numerous companies in China, and its widespread adoption has occurred in just over 10 years.
It can be said that modern architectural ceramic design began with screen printing and gradually progressed to roller printing. However, both screen printing and roller printing fall under the category of transfer printing, which has significant limitations:
1. It requires pre-made plates, which requires time, money and materials. It cannot be printed at any time, and the number of print runs is also limited.
2. During printing, the ink needs to be pressed onto the surface of the brick blank, which can easily damage the brick surface and result in a low yield rate.
3. The printing colors are relatively limited and the quality is not high.
4. Low printing efficiency, high pollution and energy consumption.
With the rapidly increasing demand for both quantity and style of architectural ceramics, screen printing and roller printing can no longer meet the needs. Although China is a world-renowned producer of building ceramics, its products have long been positioned in the low-to-mid-range market, failing to command high prices in the global ceramic tile market. This is directly related to the less advanced printing technology used. In particular, the low printing efficiency and high energy consumption are incompatible with today's society's pursuit of high efficiency and advocacy of energy conservation and environmental protection, drawing pressure from various quarters. A four-color (C/M/Y/K) screen printing or roller printing machine, along with processes such as the preparation of pigments for single-color printing glazes, consumes 8500-12000 kW of electricity, which is 2000-3000 times the electricity consumption of printing machines used in ceramic tile manufacturing powerhouses like Italy and Spain! Wastewater discharge and solid waste generation from ceramic tile production account for 0.8% and 1.0% of my country's industrial wastewater discharge and industrial solid waste generation, respectively, with a significant proportion of these emissions occurring during the printing stage. The ceramic tile industry, unable to shake off its reputation for high energy consumption, high pollution, and high emissions, has long been a part of my country's energy predicament. Every year during peak electricity consumption periods, tile factories are consistently among the first to face power rationing. Due to high energy consumption and low selling prices, my country's ceramic industry consumes 3.1 times the world average and nine times that of Japan per million US dollars in energy. In response, the government has formulated a series of national standards, including the "Unit Energy Consumption Limits for Building and Sanitary Ceramics Products" and the "Emission Standards for Pollutants from the Ceramic Industry." According to these standards, over 20% of small and medium-sized ceramic enterprises will face elimination if they fail to meet the requirements.
This demonstrates that China's ceramic building materials industry is facing both internal and external challenges. Without technological transformation and innovation, it risks falling into a vicious cycle of high energy consumption – low added value – no market – no funds for transformation – high energy consumption. The industry is also seeking more advanced printing technologies. The introduction of inkjet printing technology in early 2010 was a major revolution in ceramic printing technology!
Inkjet printing technology
Inkjet printing technology is a plate-free and contactless inkjet printing technology. It directly images electronic images onto the surface of ceramic media, eliminating many processes in traditional ceramic printing, thus overcoming the limitations of traditional printing technologies and achieving effects that the previous two technologies could not produce.
The working principle of inkjet printing technology is similar to that of an inkjet printer. The desired color pattern is transmitted and processed by a computer, and then special ink is printed onto the raw ceramic tile. The entire printing process takes only a few seconds. After that, it is fired at high temperature to become a beautiful and colorful ceramic tile product.
The structure of an inkjet printer mainly includes a frame support system, a feeding system, an ink supply system, a printhead system, a cleaning system, and a display and control system. The most crucial component is the inkjet printhead in the printhead system. Additionally, the ink and computer transmission equipment also involve high-tech components. Inkjet printheads fall under the category of microelectromechanical technology and currently primarily use piezoelectric inkjet printheads. These printheads have a cavity above the nozzle that stores a certain amount of ink. Piezoelectric ceramics are mounted on the outside of this cavity. When subjected to a pulse voltage, the piezoelectric ceramics deform, generating pressure that squeezes the ink in the nozzle, causing it to be ejected. The ejected ink falls onto the printing medium, forming ink dots. Ink dots ejected from different colored nozzles combine to form a pattern. The nozzles on the printhead are connected to ink tubes. An ink supply system that precisely controls the ink volume and pressure provides a continuous supply of ink to the printhead. The print control system then controls the piezoelectric ceramics in the nozzles to obtain the desired printed pattern.
Inkjet printing, through high-resolution digital transmission, accurately reproduces every detail of natural stone textures, achieving truly diverse and ever-changing patterns. It can print not only on raised and recessed surfaces but also on beveled surfaces, and is not limited by repeated overprinting of local textures, allowing each tile to have a unique texture and richer variations to meet the personalized needs of different customers. With the advent of inkjet printing technology, tile production will transition from a "copying" era to a "printing" era.
In fact, inkjet printing technology had been widely used in the ceramics industry in countries such as Italy and Spain for several years, but exports to countries outside Europe had been restricted. It wasn't until 2009, after the financial crisis, that the Italian company SERTAM showcased its PINK series inkjet printers at the Guangzhou Ceramic Industry Exhibition, marking the first breakthrough in the foreign blockade of inkjet technology to China. Hangzhou Nobel Tiles was the first to introduce the Italian Kerajet digital inkjet printing system and launched the Cezanne digital series in early 2010. Subsequently, Kunshan Champion launched the Rotodigi Royal Digital series, a collaboration with the Italian company System, integrating roller printing and inkjet printing. Shanghai Smic launched glazed tiles and the Zhizhen Fantasy series, produced using the German-Italian collaborative INK-CID digital inkjet printing system. Gold Medal Asia used imported Italian NEWTECH inkjet printers to launch Gold Medal Avatar 3D inkjet tiles, among others.
Currently, there are about a dozen imported inkjet printers operating in various factories in China. Meanwhile, some domestic equipment manufacturers are also accelerating their research and development of inkjet printers. Shanghai Taiwei Technology Development Co., Ltd. has already developed the TeckBlaze1500 offline experimental machine, the TeckVersa700 online production machine, and the TeckVersa1000 online production machine for ceramic tiles. At the Guangzhou Ceramic Industry Exhibition that concluded in May 2011, a total of 12 domestic and foreign ceramic machinery manufacturers showcased ceramic tile inkjet printers. This suggests that the use of ceramic tile inkjet printers in my country should experience rapid growth in the next five years!
Figure 1. Appearance of the TeckVersa 700 developed by Shanghai Taiwei Technology Development Co., Ltd.
Advantages of inkjet printing technology
Compared with traditional screen printing and roller printing, inkjet printing technology has significant advantages, specifically in the following aspects:
I. Product Quality
Inkjet printing technology has revolutionized traditional contact pressure printing, enabling printing on uneven surfaces, slopes, and thin ceramic tiles. It allows for multi-angle, high-density printing, fully showcasing the three-dimensional surface effect of ceramic tiles.
Inkjet printing boasts a resolution exceeding 360 dpi, resulting in high realism. It can display dozens of colors on a single tile, even showcasing color gradations, and reproduce various natural textures in both color and feel. Compared to the four colors (or six for special applications) of traditional screen printing, inkjet printing offers a richer and more vibrant color palette.
II. Pattern Design
Since it does not require the plate-making process of traditional printing, the patterns can be common marble textures or landscape photos taken casually on the street, allowing for greater design freedom and enabling designers to fully utilize their professional abilities to create the most suitable products for customers.
III. Operation Control
Inkjet printing breaks the limitations of traditional printing methods in terms of the number of printing plates, enabling flexible small-batch production. A single person can operate a single medium-sized machine, and the production space can also be reduced.
IV. Production Efficiency
From design output to plate making, printing, and firing, traditional screen printing takes at least three days, and roller printing takes at least two days. In contrast, inkjet printing technology takes only three to four hours from design output to inkjet printing and firing, greatly improving production efficiency.
V. Reduce energy consumption
Inkjet printing technology significantly reduces product development or production conversion costs by eliminating plate making and limitations on design and printing volume. Finished products can be printed on demand, achieving zero inventory.
Inkjet printing uses a spraying technology, which consumes less ink and pigment, resulting in high ink utilization and almost no waste. Furthermore, high efficiency, low energy consumption, high yield, and minimal waste and emissions are also key advantages of inkjet printing technology in reducing energy consumption.
The following comparison table can illustrate the situation quite clearly:
Table 1: Process Comparison of Inkjet Printing and Traditional Printing Technologies
Table 2: Comparison of the overall performance of inkjet printing and traditional printing technologies
Future Prospects of Inkjet Printing Technology
In China, inkjet printing for ceramic tile manufacturing is an emerging technology and a new trend in the industry, still in its early stages compared to European countries. Italy and Spain are leading nations in tile production technology, accounting for 22.5% of global tile production. Although their output is less than China's, their widespread use of digital inkjet printing technology results in prices 3-12 times higher than the average price of Chinese exports. The comprehensive energy consumption (≤300 kWh/t) and comprehensive electricity consumption (≤360 kWh/t) of building and sanitary ceramic enterprises in these two countries are more than 14% and 10% lower than those of Chinese enterprises (≤350 kWh/t and ≤400 kWh/t, respectively). The advantages of inkjet printing technology indicate that its development will inevitably reduce energy and production costs, increase selling prices, and generate more profits. It will also likely receive government support, making the rapid development of inkjet printing technology in China an inevitable trend.
The development of inkjet printing technology will inevitably promote the localization of inkjet printing equipment. The core of inkjet printing technology lies in the inkjet printhead, ink, and computer transmission equipment. Before localization, the high purchase price and maintenance costs directly constrained the development of inkjet printing in China. China currently has 4200-4500 ceramic tile kiln production lines (excluding small kilns), each requiring 1-2 printing machines. Assuming an average annual installation rate of 5%, the market potential is over 200 units per year. Based on an average selling price of 3.5 million yuan per unit (approximately 5.5 million yuan for imported equipment) and a gross profit margin of 50%, the profit is considerable, not including future production line growth and equipment upgrades. This profit and business opportunity will inevitably drive some capable companies to invest in research and development and production. In the next few years, the market structure of ceramic tile inkjet printers in my country may be one-third entirely imported, one-third with imported printheads, software, and circuit boards, and one-third with only imported printheads and other components localized. In this regard, Shanghai Taiwei Technology Development Co., Ltd. has taken the lead in promoting the localization of ceramic tile inkjet printing equipment to the greatest extent possible.
Currently, over 85% of ceramic tile production lines in Europe utilize inkjet printing technology, with more than 300 machines employed. The current state of ceramic tile printing technology in Europe will be the direction for the development of printing technology in China's ceramic tile industry in the coming years. China will undoubtedly transform from a major ceramic tile producer into a leading technological power in the future!
About the author:
Huang Fengge graduated from Henan University in 1997 with a major in Chemical Engineering. He currently works at Shanghai Taiwei Technology Development Co., Ltd., where he is primarily responsible for the development and production of ceramic tile inkjet printers.
References:
1> Notice on Conducting Special Inspections of the Implementation of Unit Product Energy Consumption Quota Standards and the Elimination of High-Energy-Consuming and Outdated Mechanical and Electrical Equipment (Products), Department of Energy Conservation and Comprehensive Utilization, Ministry of Industry and Information Technology of the People's Republic of China, http://jns.miit.gov.cn/n11293472/n11295091/n11299314/13310547.html , July 20, 2010
2> Analysis of the Economic Operation of the Building Materials Industry in 2008, Raw Materials Industry Department, Ministry of Industry and Information Technology of the People's Republic of China, http://www.miit.gov.cn/n11293472/n11295125/n11299425/12164560.html, March 11, 2009
3> Guidance Catalogue for Industrial Structure Adjustment, 2011 Edition, issued by the National Development and Reform Commission of the People's Republic of China.
http://www.ndrc.gov.cn/zcfb/zcfbl/2011ling/t20110426_408008.htm , March 27, 2011
4> Inkjet and fully polished glaze technologies propel ceramic tile manufacturing into a new era. China Ceramics Network, December 22, 2010
