Abstract: A marking instrument, such as a pen, is disclosed. The marking instrument includes a marking tip carried at the end of a tubular member for conducting marking fluid to the marking tip. The marking tip includes a tubular rear end section of circular cross-section. The tubular member is elliptical in cross-section and is attached to the tubular rear end section of the marking tip at an angle to the longitudinal axis of the tubular member. The elliptical shape of the tubular member allows for a circular profile opening when the tubular member is cut at an angle to join the tubular rear end section of the marking tip. Because the complementary profiles are circular in shape at the connection plane, it is not necessary to rotationally orient the components when bringing them together to be joined.

Abstract: A ball point pen has a hollow nib member (2) attached to the end of a cylindrical body (1) enclosing a ink reservoir (3), the forward end of the nib member being spaced from the axis (B) of the body and having a tip element (4) welded thereto so that the writing ball (6) incorporated in the tip is located on the same side of the axis (B) as the forward end of the nib member.

Abstract: A marking instrument includes a reservoir chamber for marking fluid, a channel for conducting marking fluid from the reservoir chamber for supply to a marking tip, and a valve for controlling supply of fluid through the channel. The valve includes a seat member with a port, a diaphragm having an edge for cooperation with the seat member to close the port, and a free surface extending from the edge to a position at which the diaphragm is held against movement. The seat member is movable to deflect the diaphragm for opening the valve. The free diaphragm surface extends away from the edge at an angle of 45.degree. to 85.degree. when the valve is closed.

Abstract: A marking instrument, such as a reservoir pen, has a valve for controlling communication between a reservoir chamber and a feed channel extending through a feed member to a marking tip. The feed member is retractable to open the valve when the tip is pressed against a surface. A subchamber is confined by a diaphragm sealingly connected between the feed member and the barrel, and when the marking tip is lifted from the surface, the diaphragm pushes the feed member forwardly so that the valve closes, after which the volume of the subchamber increases so that the ink is drawn through the channel from the tip.