Quick start note:

Please remember to shake your new pen downwards few times dynamically after inserting the very first ink cartridge to jump start the ink flow.

It's done correctly when you see first drops of ink come out through the pen's nib (which will get the nib initially a bit moist). Best if you do this process above a piece of paper or above the kitchen sink to not stain your surroundings.

Here are 2 great customers video-reviews showing the jump-starting process:




This will allow the ink to start flowing smoothly for the first usage with cartridges (process not needed with the ink bottle).

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Our vintage and modern fountain pens are crafted to accept either a disposable ink cartridge (not included)* or an ink converter (included inside the pen's barrel).

Ink cartridges vs converts

The most widely compatible ink cartridge size that exist is the international, generic size, which can be used for 90% of all fountain pens in the world, including all ZenZoi® pens.

We do not lock you in for the proprietary cartridge shape or size like most brands do.

You can choose to buy big packs of ZenZoi ink cartridges from us, or to get any other brand's international size cartridges.

A fountain pen ink converter looks like an empty ink cartridge with a turning screw at the back-end. Inserting the converter into the front section of the fountain pen allows you to draw up the bottled ink through the nib by turning the knob, like in a twistable syringe.

Converters, if cleaned often after filling of the ink, can be reused for many years and do not need to be replaced often.

Pros: Fountain pen users have the luxury and convenience of choosing between two filling options. Cartridges are easier and less prone to creating a mess while converters are more cost effective and provide a sense of nostalgia for old-fashioned pen users.

Cons: Disposable ink cartridges have to be replaced more often and are less cost effective than a bottle of good ink. Filling using a converter can be messy for the novice fountain pen user and may require more cleaning or maintenance.

 Common types of fountain pen cartridges

International Size Ink Cartridge Refill


IMPORTANT TIP: When buying ink cartridges for your ZenZoi® pen please get cartridges shown above and stay away from branded ones as they often fit only one particular brand that sells them (typical practice of some brands to lock users with their brand).

You should be able to easily recognize these proprietary cartridges as their shape or size does not meet international standard, is odd and fits just one brand selling them. Some examples are below. 

Examples of non-standard ink cartridges that would fit only

The Brand That Makes Them




Another option for refilling your pen is bottled ink. You would use the converter included inside your pen to draw ink directly from any ink bottle of your choice.

The most commonly used types of inside converters are piston and squeeze types. 

The one we use with our pens is piston type (as we find it more precise and not causing air bubbles) which is included inside the barrel of every ZenZoi® fountain pen. 

This youtube link below shows how to refill piston type of converters by placing the nib inside the ink bottle and twisting the converter: