Ink applicator, ink backflow prevention mechanism of ink applicator, and a pen tip

An applicator comprising:

• an ink reservoir, an ink-dispensing penpoint tip having a stepped diameter opening at an upstream end defining a valve support at the upstream end and a valve mechanism, wherein the valve mechanism comprises a valve body movable in directions in which an ink flows, a valve seat disposed upstream of the valve body and adjacent to the ink reservoir, the valve support disposed downstream of the valve body and adjacent to the penpoint tip and, wherein the valve support is capable of coming into engagement with the valve body such that at least one interstice is provided between them for passage of the ink, and the valve body is capable of resting on the valve seat so as to inhibit the ink from flowing backwards if and while the tip of said applicator stands facing upwards, whereas the valve body is caused to rest on the valve support to permit the ink to flow through the at least one interstice and towards the tip if and while the tip faces downwards, wherein the valve body's portion contacting the valve support is spherical in shape, and in a projection of the valve body and the at least one interstice made onto a plane perpendicular to the direction in which the ink flows in a region of the at least one interstice as not hidden with the valve body has a total area of at least 0.035 mm2, there being a surface on the penpoint tip that extends continuously and uninterruptedly through 360° around the valve body with the valve body resting on the valve support.

An applicator comprising:

• a penpoint tip having a distal end in which a writing ball is secured and having an ink-feeding bore extending through and along an axis of the penpoint tip, the applicator further comprising:
• an ink reservoir for holding therein an amount of an ink, a connector for connecting the penpoint tip to the reservoir, a communicating bore formed through the connector so as to communicate with both the ink reservoir and the penpoint tip, and a valve seat formed in the communicating bore such that a valve body moving axially of the pen is allowed to rest on and engage with the valve seat, wherein the penpoint tip has an increased-inner-diameter region that is formed in and adjacent to an opening of the ink-feeding bore and located in the connector so that the valve body is capable of transferring at least partially into the ink-feeding bore, and the ink-feeding bore has an engagement portion capable of engaging with and temporarily stopping the valve body in such a manner that at least one interstice for passage of the ink is provided between the engagement portion and the valve body, the penpoint tip comprising a single piece defining the distal end in which the writing ball is secured, the increased-inner-diameter region, and the engagement portion, whereby with the penpoint tip facing upwards, the valve body tightly rests on the valve seat so as to prevent the ink from flowing backward, whilst the valve body moves into the ink-feeding bore and engages with the engagement portion so as to allow the ink to flow through the at least one interstice towards the writing ball if the penpoint tip is held in position facing downwards, wherein with a projection of the valve body and the at least one interstice made onto a plane perpendicular to the axis of the penpoint tip, a region of the at least one interstice as not hidden with the valve body has a total area of at least 0.035 mm2.

An applicator comprising a penpoint tip having a distal end in which a writing ball is secured and having an ink-feeding bore extending through and axially of the penpoint tip, an ink reservoir for holding therein an amount of an ink, a connector for connecting the penpoint tip to the reservoir, a communicating bore formed through the connector so as to communicate with both the ink reservoir and the penpoint tip, and a valve seat formed in the communicating bore such that a valve body having a diameter and moving axially of the penpoint tip is allowed to rest on and engage with the valve seat, wherein the penpoint tip has an increased-inner-diameter region that is formed in and adjacent to an opening of the ink-feeding bore and located in the connector so that at least 40% of the diameter of the valve body is capable of transferring into the ink-feeding bore, and the ink-feeding bore has an engagement portion capable of engaging with and stopping the valve body in such a manner that an interstice for passage of the ink is provided between the engagement portion and the valve body, whereby with the penpoint tip facing upwards, the valve body is allowed to tightly rest on the valve seat so as to prevent the ink from flowing backward, whilst the valve body is capable of moving into the ink-feeding bore and engaging with the engagement portion so as to allow the ink to flow through the interstice towards the writing ball if the penpoint tip is held in position facing downwards.