Uniball Advances With Signo TSI Erasable Ink Pens

I’ll admit it, when it comes to erasable ink pens, I never much liked the now 5-year-old Uniball Fanthom.

The ink seemed a little washed out and it never quite erased all the way. Simply put, there were other pens that did it better than Uniball.

Now? Not so much.

Uni TSI Erasable Pen Black

Uniball has stepped up its game in a big way with the recent introduction in the UK of the Uniball Signo TSI. It’s an erasable pen that looks better, handles better and erases much, much better than the Fanthom.

According to Uniball, the Signo TSI uses an ink formula that is similar to the Fanthom. However, it’s an improved version. The TSI will replace the Fanthom completely as stocks run out.

The Signo Thermo-Sensitive Ink is a gel stick pen available in a variety of colors from basic black to violet to sky blue. It comes with two erasers, one on the end of the pen and one on the cap, so it’s easy to make quick corrections.


The design is a sleek barrel that is half hatched silver and half the color of the ink. One of the niftier elements is a translucent cap with a tiny rubber cap inside where the 0.7 mm tip nests.

The overall effect is more adult than the Fanthom, which always seemed to be geared toward ‘tweens.

The biggest difference, however, is in the ink itself. I wrote on a sheet of paper with both the Fanthom and the Signo TSI and then tried “erasing” the ink. (The ink isn’t actually removed – it reacts to the heat of friction from the eraser by fading from sight.)

It was no contest: The Signo TSI ink faded rapidly with fast, light strokes of the eraser. The Fanthom ink was much more stubborn, took more pressure to erase and still did not fade adequately.

Uni Ball Fanthom BP Black

Notably, the TSi also felt much smoother on the page than the Fanthom.

My one complaint about the TSI is that the ink itself is still fairly light, although mostly more vivid than the Fanthom. The one exception: The black ink in the TSI appears washed out in comparison to the Fanthom.

But overall, as far as I’m concerned, the Signo TSI is still superior to the Fanthom in nearly every way. While I won’t go so far as to say it’s better than the Pilot FriXion,  it is certainly a worthy competitor.

Since the TSI is fairly new to the UK, most of you probably haven’t tried it yet, but if anyone has, I’d love to hear your impressions.

If you are looking for an erasable pen or would like to know more about them then why not check out our Complete Guide Guide to Erasable Pens.

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Tony Bridges

As a seasoned journalist and freelance writer, I've spent over three decades telling stories and exploring the world through the written word. With a passion for writing instruments, I found my niche at The Pen Vibe, a blog that shares our collective fascination with pens, pencils, and other tools that have shaped the art of writing.

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