Abstract: A writing or drawing instrument including a writing tip (1) disposed at a front end of the writing instrument which can be brought into contact with a writing or drawing pad, a writing fluid reservoir (7) for supplying the writing tip (1) with writing fluid, and a writing fluid chamber (9) disposed between the writing tip (1) and the writing fluid reservoir (7). The writing fluid chamber (9) consists of a bubble of a flexible, inelastic material. The writing fluid chamber (9) is connected to the writing tip (1) on one side and is connected on the other side to a barrier (12). The barrier (12) is connected with the writing fluid reservoir (7) and can be opened in a controlled manner. When a lower fill level is reached in the writing fluid chamber (9), the barrier is briefly opened to fill the writing fluid chamber (9). During the filling of the writing fluid chamber (9), the volume of the writing fluid reservoir (7) is reduced in accordance with the consumption of the writing fluid.

Abstract: A writing or drawing instrument wherein a housing (1), is provided with a writing point (2) and a writing fluid reservoir (3) within an interior space of the housing. A capillary pressure equalization system (5), that connects the reservoir with the ambient air, has a sensor (7) therein for reacting to the level of writing fluid (4) therein. A suction pump (11, 12) is connected with the writing fluid reservoir (3) through a semi-permeable membrane (10) which lets air through and is impermeable for writing fluid (4). The suction pump (11, 12) is activated by the sensor (7) in response to a level of writing fluid (4) in the pressure equalization system, and aspirates air from the reservoir so as to quickly reduce an overpressure condition.

Abstract: A stylo pen tip with a drop weight body (7) which is located inside an inner bore (6) of a housing (1,1') connected with the writing fliud reservoir (16) and which has a cleaning wire (8) at its front end extending into the writing tube (2) supported on the front end of the housing (1, 1') has a drop weight safety (13) supported therein which is pivotable around the longitudinal axis of the housing (1,1') and which is in interlocking contact with the drop weight body (7), which can be moved back and forth axially in a limited way in relation to it. In its forward position the drop weight body (7) adjoins with its front end (10) a stop face (9) formed in the inner bore (6). The plane of the front end (10) of the drop weight body (7) and the plane of the stop face (9) are inclined towards each other. By turning of the drop weight body ( 7) the extension of the cleaning wire (8) beyond the front end of the writing tube (2) can be adjusted.