This blog post examines the role unprinting technology has assumed within the contemporary trend of reducing paper consumption, offering a balanced analysis of its significance and potential.

The Emergence of the Unprinting Concept

On June 24, 2011, South Korean designer Kim Su-yeon unveiled her concept design ‘Reverse Printer’ on the design webzine Yanko Design. As the name suggests, this printer performs the exact opposite function of a conventional printer. It was a device designed to erase text from printed paper, allowing it to be reused like new paper. In an era where paper is easily discarded, this idea garnered significant attention, and its potential for commercialization was positively evaluated. Following continuous technological development by various researchers, this idea progressed beyond a simple concept into the stages of experimentation and application. This research, established under the name ‘unprinting technology,’ has been primarily led by a research team at Cambridge University.
In modern society, the habitual use of new paper is common, often over active reuse of scrap paper. Some companies even force the recycling of documents containing personal information for cost-saving reasons. While these issues highlight the need for unprinting technology, the recycling of personal information documents itself was not the core motivation for its development. Nevertheless, as societal demands for reduced paper usage grow and interest in efficient print material utilization increases, unprinting technology has gained greater attention. It is now necessary to examine the progression of this technology, tracing its development from past experimental attempts to recent technological trends.

Toshiba’s Attempt: Special Ink-Based Fading Technology

Among the earliest attempts at unprinting technology, the most notable case was an experiment by Japan’s Toshiba. Toshiba developed e-blue ink, a specially designed ink intended to erase printed characters. This required an ink that would fade easily when heat was applied, utilizing the principle of thermal paper in reverse. Thermal paper is coated with chemicals that change color when heated; these chemicals consist of a leuco dye and a chromophore. When heat and pressure are applied, these two substances react to produce color. Toshiba applied this principle in reverse, developing a heating device in 2012 that could erase e-blue ink.
This device worked by applying heat between 120 and 140°C to printed paper, breaking the bond between the chromophore and the pigment to restore it to a colorless state. It also used an quencher to prevent the chromophore and pigment from rebonding and reforming the color. Devices based on this principle were designed to allow paper reuse up to 10 times and were also more cost-effective than previous technologies. However, its compatibility only with dedicated ink and dedicated printers was a critical limitation. Introducing this technology into existing office environments required replacing all printers, leading to the unfortunate outcome that Toshiba’s device did not gain widespread adoption. Nevertheless, Toshiba’s attempt was an important case study in demonstrating the direction of technological development by seeking to implement the unprinting concept in an actual machine.

Laser-Based Unprinting: Advances from Cambridge University Research

While Toshiba focused on proprietary ink, the Cambridge University research team concentrated on a method that could utilize existing printers and paper. They experimented with various techniques—mechanical scraping, chemical solvent treatment, and laser irradiation—to find a way to remove only the toner without damaging the paper. They concluded that the most stable and effective method utilizes nanosecond-duration laser pulses.
Laser unprinting technology vaporizes the polymer compounds in toner by irradiating it with a laser. Most toners consist of plastic-based polymers and carbon; applying a laser of appropriate intensity vaporizes only the toner, leaving the paper itself intact. After experimenting with various wavelengths and pulse durations, the research team discovered that irradiating with a 532nm green visible light laser in 4-nanosecond pulses yielded the most stable results. This method did not depend on specific inks or papers, ensuring high compatibility with existing printing environments.
However, numerous challenges remained for commercialization. Unlike achieving optimal conditions in a lab setting, consistent performance proved difficult in real office environments due to the wide variety of papers and toners used. Additionally, initial equipment development costs were high, and technical design was required to safely operate the laser device. To tackle these challenges, the research team established the venture company Reduse in 2013 to continue R&D.

Reduse’s Establishment and Technology Commercialization Phase

Reduse was founded with the goal of commercializing unprinting technology. From its inception, the company participated in various competitions to secure research funding. As a result, it won a major startup competition in the UK in 2014, securing substantial research funding. Subsequently, it expanded its operations by recruiting specialized technology managers. Reduse refined its technology by conducting experiments verifying the unprinter’s performance on actual corporate documents and is now focused on enhancing product maturity.
However, as of 2025, there are no reports indicating laser unprinters have reached widespread adoption in office settings. While research continues, challenges remain unresolved: ensuring economic viability, safety, and stable performance across diverse printing environments for commercial application. Nevertheless, Reduse’s efforts have laid the groundwork for significant advancements in the print regeneration field.

Recent Changes: Eco-Friendly Printing Technologies and New Research Trends

With the global emphasis on sustainability and environmental protection in the 2020s, the printing industry is also undergoing major changes. Companies are reducing paper usage and strengthening digital document workflows, while the adoption of eco-friendly inks, recycled paper, and energy-efficient printing equipment is expanding. These changes prompt a broader re-evaluation of the necessity for unprinting technology.
Furthermore, in 2024, a new technology was announced that allows printed cork paper to be reused after ink removal. This demonstrates that the concept of “post-print restoration” can be applied not only to paper but to various materials. In other words, the scope of unprinting technology is not limited to single sheets of paper but holds potential for expansion into a wider range of materials.
Within this trend, unprinting technology still holds valid potential. However, commercial unprinters have yet to become widespread in the market, and digital documentation and eco-friendly printing methods have established themselves as practical alternatives. Nevertheless, considering the reality that paper cannot be completely replaced, unprinting technology is highly likely to regain attention in the future.

Conclusion: From Past Experimentation to Future Potential

Over the past decade, unprinting technology has steadily evolved from concept design to laboratory research and now to the stage of commercialization preparation. It is highly significant that diverse approaches—from Toshiba’s dedicated ink-based technology, to the Cambridge research team’s laser unprinting technology, and recent advancements in environmental technology and recycled material research—have converged into a single trend.
While commercial unprinters are not yet in use in offices worldwide, the social movement to reduce paper consumption and strengthen resource circulation continues. This trend grants new possibilities to the technological imagination of unprinting. If this technology, bridging the gap between printing and recycling, becomes a reality, the ways we use paper and preserve the environment could change significantly.