Abstract: A fountain pen comprises a hollow barrel such as can be held by a user, a nib stably attached to one end of the hollow barrel, also an ink cartridge housed internally of the hollow barrel and having a given containment volume. The cartridge is connected to the nib by way of a feed through which ink flows to the nib, and deformable by expanding at least partially between a normally undeformed first configuration, and a deformed second configuration in which the containment volume created internally is greater than the containment volume in the undeformed configuration.

Abstract: A fountain pen comprises a hollow barrel such as can be held by a user, a nib stably attached to one end of the hollow barrel, also an ink cartridge housed internally of the hollow barrel and having a given containment volume. The cartridge is connected to the nib by way of a feed through which ink flows to the nib, and deformable by expanding at least partially between a normally undeformed first configuration, and a deformed second configuration in which the containment volume created internally is greater than the containment volume in the undeformed configuration.

Abstract: A pen comprising a cartridge, a retaining sleeve for at least partially accommodating the cartridge, a locking device which can be actuated by rotation for locking the cartridge and the retaining sleeve together and a cap for protecting the cartridge, wherein the cap is displaceable axially in relation to the locking deice from a first operating position in which it is rotatable with respect to the locking device into a second operating position in which it is rotationally coupled to the locking device. The cartridge is axially displaceable with respect to the locking device, more specially by at least a distance which is equal to the spacing between the first and second operating positions of the cap.