Pens and Pencils | Reviews and Data

Uni-Ball Develops The First Paper Pen Refill

Unsharpen may earn a commission when you buy through links on our site.

In an effort to reduce the use of plastic and increase the amount of biodegradable components used in pens, Mitsubishi Pencil Company’s Uni-Ball brand has developed a ballpoint pen refill made primarily of paper.

Paper Pen Refill Pipe

The refill, which is patent pending and not yet named, uses a main component — the long piece that looks like a straw — that is made of paper instead of plastic or metal, as it was in older pens. This change is said to reduce the amount of plastic in the refill design by 88%.

As the refill is still in development not much has been said officially about it, but it seems to be a Uni-Ball Jetstream refill, based on the shape and the Jetstream’s categorization as a ballpoint pen. The new paper refill looks to be an alternative to the Jetstream SXR line, like the popular SXR-5 found in the 0.5 mm Jetstream pens.

The company mentioned that the Jetstream ink inside the refill would have the smoothness expected from the line and that, as a major bonus, the new refill would have 1.6 times the capacity of a standard SXN-150 Jetstream refill.

The paper part of the refill is said to have three layers of specialty paper surrounds by a fourth layer, which is the parchment paper you can see in the image Uni made available. The paper was designed to be impermeable to the ink as well as to prevent drying out and to be strong enough to stand up to installation. Plus it needs to simply last for years at a time, which is a challenge for any refill.

The refill was developed alongside Nippon Paper Industries — presumably the paper maker — and Showa Marutsutsu, a packaging company.

No potential release date was announced yet, but we’ll follow the news and update when possible.


This patent seems to be EP3613603A1, or at least that was the closest we could find. This was filed in 2018, so it might be a previous or related work to the current design. This patent is for an “environment-friendly ink storage pipe for writing utensils with reduced use of plastics by using a paper base material instead of plastics such as a polypropylene” which sounds exactly correct. The current assignee is Mitsubishi Pencil Co Ltd.

Other Refills Patents

This is not the first green pen refill patent we’ve seen. In fact, in 1998 the Eversharp pen company filed a patent for a recyclable paper and plastic refill design.