Even in today's digital age, 90% of the business is documented on paper and an average office worker prints out 10,000 sheets of paper per year although to be read just once before being discarded. Recent developments have sparked up rewritable papers, which are energy-intensive in their manufacture, and therefore, expensive. Also, some of them use inks which possess environmental hazards. However, this new type of paper developed by Chinese researchers at Jilin University combines the concepts of reusable paper and erasable ink into one product.

This paper contains hydrochromic dyes (hydro=water, chromic=relating to colour). Therefore, as the name suggests, this paper utilises water as ink. The dyes are invisible when the paper is dry but words appear where the paper is wet. To test the prototype, the researchers simply filled the cartridges with water and printed on the paper using an ordinary HP desktop printer. One could hardly spot a difference.
a. Printed using water as ink on hydrochromic paper b. Using conventionl paper using standard ink
Printer ink costs have escalated sharply over the years and according to some estimates, the cost of printing ink for over three years could be seven times the cost of printer. This paper could be the solution to the rising costs and to the Printer Ink Facts. The printing costs of hydrochromic paper using water as ink are less than 1% than that of normal printing using inkjet printers. However, the ink lasts for a short time until the paper dries out. On the recent test prototype, it lasted for 22 hours. Also, the paper can be reused a dozen times. Therefore, although not applicable for all situations, this paper can be used in a variety of them (memos, reminders, etc.).

A comparison of cost of various printers and their printing costs for an year is given below:

Nevertheless, this paper could trim down office stationary budgets and also give environmentalists a reason to smile.

Source: #-Link-Snipped-#, #-Link-Snipped-#