Shut-off Valve

Eyedropper pens with shut-off valve are a very Japanese idea, we all know by now. This idea is, in essence, a simplification of the plunger filler implemented by Onoto on the fountain pens arriving in Japan around 1900. The plunger filler is no longer there, and the tail knob now operated the axis moving the cone that opens and closes the connection between the ink deposit and the section.

Mostly all Japanese companies used this mechanism at some point. Some examples have been shown on these chronicles: Asahi-Tsubasa, Ban-ei, The Eiko, New Clip, Pilot-Namiki, Platinum, Platon, SSS, (Japanese) Swan,… As of today, Pilot-Namiki, Nebotek and Danitrio still make this type of shut-off valve.

SSS in black ebonite. The sealing cone is visible inside the barrel.

Swan (Japan) number 5. The section is disassembled from the barrel. The sealing cone and its axis are visible.

However, my experience using these pens is very limited. Their weakest point is the seal between the axis and the top end of the ink deposit. This thin rod must slip up and down through this seal to allow the ink to pass through the valve to the section and the feed. Traditionally, this seal was made of cork and lack of use and the passing of time are good arguments for ink leaks. In such case, these pens become very messy—ink would leak through the tail knob when turning it to open the valve.

The tail knob of the Danitrio Ban-ei.

After trying with some vintage pens –a SSS made of ebonite, with stained results—I decided to ink a Danitrio Ban-ei. Being modern, it is in good shape and there are no leaks. Then, how does it perform?

Its nib is a very smooth unit made by Kabutogi Ginjiro. It is nicely wet—as long as the there were ink actually flowing through the feed. So, in principle, this pen performs well—open the valve, uncap the pen, write. However, sealing the ink deposit when not in use has some side effect—the nib quickly becomes dry. My contention is that the lack of connection between nib and deposit deprives the first of a permanent supply of ink. Then, the natural evaporation simply dries the nib up and this space cannot be refilled with more ink from the deposit. If stored with the valve open, the nib does not become dry.

I wonder if that was the case with other eyedropper pens with shut-off valve.

(Danitrio 挽栄, Ban-ei – Sailor Jentle 土用, Doyô)

Bruno Taut

April 17th, 2012

[labels: Danitrio, soluciones técnicas, nibmeister Kabutogi]