Signo DX

Shop UniBall Signo DX ↗

A model in UniBall's fountain pen lineup. Specs below reflect the typical configuration across UniBall's core range.

A solid mid-range option once someone has decided fountain pens are a habit worth investing a bit more into.

Specs

Filling systemCartridge / converter (typical for most fountain pens)

Ink capacityVaries by model

Nib optionsF, M (steel, typical)

MaterialResin or metal

Typical priceVaries — check current listings

How long has your Signo DX been inked?

Inktend counts the days and reminds you when it's time to clean.

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About UniBall

Uni-ball is the flagship writing brand of Mitsubishi Pencil Co., founded in Tokyo in 1887 as the Masaki Pencil Manufacturing Company and unrelated to the Mitsubishi Group. The uni-ball name first appeared in 1979 on a water-based rollerball pen, and the company, which sells products in over 100 countries, acquired German penmaker Lamy in 2024.

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How to fill the UniBall Signo DX

Fill it two ways: snap in a pre-filled international cartridge for convenience, or use a converter — a small plunger or twist mechanism that installs the same way a cartridge does — to draw ink from any bottle. The converter route opens up the entire world of bottled ink, which is where most of the hobby's color variety lives.

Choosing a nib size

Nib size determines line width, not writing pressure — fountain pens are meant to glide, never press. Extra-fine (EF) suits small, dense handwriting and thin paper; fine (F) is the most broadly recommended default; medium (M) shows more ink character and shading; broad (B) and stub grinds favor bold, expressive strokes and calligraphy-adjacent writing.

Keeping it clean

A quick flush with cool water every time you switch ink colors — and a full clean every 4–6 weeks of regular use — is enough to keep the nib and feed performing well. Inktend's cleaning reminder is tuned to a 21-day baseline and adjusts naturally to how often you actually refill.

Pairing inks with the Signo DX

Because refills are quick with a cartridge or converter, this is a good pen for rotating through several colors rather than committing to one; sample vials work especially well here.

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Frequently asked questions

How do I fill the UniBall Signo DX?

Snap in a pre-filled cartridge, or use a converter to draw ink from any bottle. The converter route is the cheaper long-term option.

What nib size should I get for the Signo DX?

Fine (F) is the safest default for a first pen. Go finer for small, dense handwriting; go broader if you want more ink character and shading.

How often does the Signo DX need cleaning?

Flush it each time you switch inks, and give it a full clean every 4 to 6 weeks of regular use.

Is the UniBall Signo DX good for beginners?

It can work as a first pen if you're comfortable spending a bit more to start.

Specs reflect the typical configuration across UniBall's core lineup rather than this exact model — check current listings before buying.