A nib for a refillable free ink writing felt pen includes a body and a dry ink tank including dry ink, the dry ink tank being delimited by the body of the nib and a dry ink tank wall including a water-soluble film.

A nib for a refillable free ink writing felt pen includes a body and a dry ink tank including dry ink, the dry ink tank being delimited by the body of the nib and a dry ink tank wall including a water-soluble film.

Provided are a liquid storage and release device and a pen comprising the device. The liquid storage and release device comprises a tube shell (1), a capsule-like liquid container (3), a piercing component (4) and a piston rod (5), wherein the tube shell (1) is open at one end and closed at the other end, and the interior thereof is a tube cavity (2); the capsule-like liquid container (3) and/or the piercing component (4) is/are slidably arranged in the tube cavity (2); one end of the piston rod (5) is slidably arranged in the tube cavity (2) of the tube shell (1), and the other end of the piston rod (5) is provided with a liquid release opening (6); and the piston rod (5) is provided with a liquid channel through which the liquid release opening (6) is in communication with the tube cavity (2). When the piston rod (5) slides towards the interior of the tube cavity (2), the capsule-like liquid container (3) and the piercing component (4) apply pressure to each other under the action of the piston rod (5), so that the piercing component (4) pierces the capsule-like liquid container (3) so as to release the liquid pre-stored in the capsule-like liquid container (3).

Provided are a liquid storage and release device and a pen comprising the device. The liquid storage and release device comprises a tube shell (1), a capsule-like liquid container (3), a piercing component (4) and a piston rod (5), wherein the tube shell (1) is open at one end and closed at the other end, and the interior thereof is a tube cavity (2); the capsule-like liquid container (3) and/or the piercing component (4) is/are slidably arranged in the tube cavity (2); one end of the piston rod (5) is slidably arranged in the tube cavity (2) of the tube shell (1), and the other end of the piston rod (5) is provided with a liquid release opening (6); and the piston rod (5) is provided with a liquid channel through which the liquid release opening (6) is in communication with the tube cavity (2). When the piston rod (5) slides towards the interior of the tube cavity (2), the capsule-like liquid container (3) and the piercing component (4) apply pressure to each other under the action of the piston rod (5), so that the piercing component (4) pierces the capsule-like liquid container (3) so as to release the liquid pre-stored in the capsule-like liquid container (3).

A nib for a refillable free ink writing felt pen includes a body and a dry ink tank including dry ink, the dry ink tank being delimited by the body of the nib and a dry ink tank wall including a breakable portion.

A nib for a refillable free ink writing felt pen includes a body and a dry ink tank including dry ink, the dry ink tank being delimited by the body of the nib and a dry ink tank wall including a breakable portion.

A nib for a refillable free ink writing felt pen includes a body and a dry ink tank including dry ink, the dry ink tank being delimited by the body of the nib and a dry ink tank wall including a water-soluble film.

A nib for a refillable free ink writing felt pen includes a body and a dry ink tank including dry ink, the dry ink tank being delimited by the body of the nib and a dry ink tank wall including a water-soluble film.

In a first aspect, the present disclosure relates to a system comprising a writing instrument, wherein the writing instrument comprises a solution of one or more salts and a writing orifice. Furthermore, the system comprises a drawing substrate configured to change color based on the concentration of the one or more salts and/or water content, wherein the drawing substrate comprises cholesteric liquid-crystals.

Provided are a liquid storage and release device and a pen comprising the device. The liquid storage and release device comprises a tube shell (1), a capsule-like liquid container (3), a piercing component (4) and a piston rod (5), wherein the tube shell (1) is open at one end and closed at the other end, and the interior thereof is a tube cavity (2); the capsule-like liquid container (3) and/or the piercing component (4) is/are slidably arranged in the tube cavity (2); one end of the piston rod (5) is slidably arranged in the tube cavity (2) of the tube shell (1), and the other end of the piston rod (5) is provided with a liquid release opening (6); and the piston rod (5) is provided with a liquid channel through which the liquid release opening (6) is in communication with the tube cavity (2). When the piston rod (5) slides towards the interior of the tube cavity (2), the capsule-like liquid container (3) and the piercing component (4) apply pressure to each other under the action of the piston rod (5), so that the piercing component (4) pierces the capsule-like liquid container (3) so as to release the liquid pre-stored in the capsule-like liquid container (3).