Ballpoint pen refill and fabrication method thereof

Claim 2

A ballpoint pen refill comprising: an ink tube containing ink having a thixotropic property, said ink tube having a front end and a rear end; an ink follower within said ink tube, said ink follower being positioned behind said ink such that said ink follower moves with consumption of said ink and prevents reverse flow of said ink; a stopper having a ventilation opening, said stopper being connected to said rear end of said ink tube; a tip holder member including a longitudinal ink passage and a front end aperture, said longitudinal ink passage communicating with said front end aperture, said tip holder member further including a rear engagement portion connected to said front end of said ink tube; wherein said rear engagement portion has at least one lateral groove communicating with said longitudinal ink passage and extending radially therefrom, and at least one longitudinal groove communicating with an outer end of said at least one lateral groove and extending in a rearward direction therefrom, said at least one lateral groove and said at least one longitudinal groove forming at least one ink flow path between said longitudinal ink passage and said ink tube, said at least one ink flow path forming a partition portion at a rear surface of said rear engagement portion for restricting the ink flow from said ink tube to said longitudinal ink passage; a ballpoint pen tip connected to said front end aperture of said tip holder member, said ballpoint pen tip having a front end rim and a ball, said front end rim having a spherical inner surface complementary to an outer surface of said ball, wherein said ball is rotatably held by said front end rim; and a spring within said ballpoint pen tip, wherein said spring presses said ball against said spherical inner surface of said front end rim.

Claim 3

The ballpoint pen refill of claim 1, wherein said longitudinal ink passage is located on a center longitudinal axis of said tip holder member.

Claim 4

The ballpoint pen refill of claim 1, further comprising a movable member between said ball and said spring for transmitting force from said spring to said ball.

Claim 5

The ballpoint pen refill of claim 2, wherein said movable member has a valve portion and said ballpoint pen tip has an ink guidance aperture, said ink guidance aperture having a seat portion on a rear end thereof, said valve portion of said movable member being arranged to engage said seat portion if said ball falls out of said ballpoint pen tip, whereby leakage from said ballpoint pen tip can be prevented.

Claim 6

The ballpoint pen tip of claim 4, wherein said valve portion of said movable member is a tapered shoulder portion.

Claim 7

The ballpoint pen tip of claim 4, wherein said seat portion of said ballpoint pen tip is a tapered shoulder portion.

Claim 8

The ballpoint pen refill of claim 3, wherein said movable member has an ink-flow adjustment portion, said ink-flow adjustment portion having a plurality of longitudinal fins thereon, said longitudinal fins extending radially outward.

Claim 9

The ballpoint pen refill of claim 7, wherein said plurality of longitudinal fins define longitudinal ink passageways around said ink flow adjustment portion of said movable member.

Claim 10

A ballpoint pen refill comprising: an ink tube formed of metal and having a front end and a rear end, said ink tube including a small-diameter portion having an opening at said front end, a large-diameter portion at a rear end and a connecting portion between said small-diameter portion and said large-diameter portion, said ink tube containing ink having a thixotropic property; an ink follower within said ink tube, said ink follower being positioned behind said ink such that said ink follower moves with consumption of said ink and prevents reverse flow of said ink; a stopper having a ventilation opening, said stopper being connected to said rear end of said ink tube; an ink partitioning member fitted within said connecting portion of said ink tube, said ink partitioning member including a front end portion with a spring bearer surface, a rear end portion extending into said large-diameter portion of said ink tube, and a longitudinal ink passage opening at said spring bearer surface and extending to said rear end portion; wherein said rear end portion of said ink partitioning member has at least one lateral groove communicating with said longitudinal ink passage and extending radially therefrom, and at least one longitudinal groove communicating with an outer end of said at least one lateral groove and extending in a rearward direction therefrom, said at least one lateral groove and said at least one longitudinal groove forming at least one ink flow path between said longitudinal ink passage and said large-diameter portion of said ink tube, said rear end portion of said ink partitioning member having a rear end surface for restricting the ink flow from said large-diameter portion of said ink tube to said longitudinal ink passage; a ballpoint pen tip connected to said small-diameter portion of said ink tube, said ballpoint pen tip having a front end rim and a ball, said front end rim having a spherical inner surface complementary to an outer surface of said ball, wherein said ball is rotatably held by said front end rim; a movable member within said ballpoint pen tip adjacent to said ball; and a spring within said ballpoint pen tip between said movable member and said spring bearer surface of said ink partitioning member, wherein said spring presses said ball against said spherical inner surface of said front end rim.

Claim 11

A ballpoint pen refill comprising: an ink tube formed of metal and having a front end and a rear end, said ink tube including a small-diameter portion having an opening at said front end, a large-diameter portion at a rear end and a connecting portion between said small-diameter portion and said large-diameter portion, said ink tube containing ink having a thixotropic property; an ink follower within said ink tube, said ink follower being positioned behind said ink such that said ink follower moves with consumption of said ink and prevents reverse flow of said ink; a stopper having a ventilation opening, said stopper being connected to said rear end of said ink tube; an ink partitioning member fitted within said connecting portion of said ink tube, said ink partitioning member including a front end portion with a spring bearer surface, a rear end portion extending into said large-diameter portion of said ink tube, and a longitudinal ink passage opening at said spring bearer surface and extending to said rear end portion; wherein said rear end portion of said ink partitioning member has at least one lateral groove communicating with said longitudinal ink passage and extending radially therefrom, and at least one longitudinal groove communicating with an outer end of said at least one lateral groove and extending in a rearward direction therefrom, said at least one lateral groove and said at least one longitudinal groove forming at least one ink flow path between said longitudinal ink passage and said large-diameter portion of said ink tube, said rear end portion of said ink partitioning member having a rear end surface for restricting the ink flow from said large-diameter portion of said ink tube to said longitudinal ink passage; a ballpoint pen tip connected to said small-diameter portion of said ink tube, said ballpoint pen tip having a front end rim and a ball, said front end rim having a spherical inner surface complementary to an outer surface of said ball, wherein said ball is rotatably held by said front end rim; a movable member within said ballpoint pen tip adjacent to said ball; and a spring within said ballpoint pen tip between said movable member and said spring bearer surface of said ink partitioning member, wherein said spring presses said ball against said spherical inner surface of said front end rim.

Claim 12

The ballpoint pen refill of claim 9, wherein said longitudinal ink passage is located on a center longitudinal axis of said ink partitioning member.

Claim 13

The ballpoint pen refill of claim 9, wherein said movable member includes: a front end portion with a front end surface in contact with said ball; an ink-flow adjustment portion having a rear surface in contact with said spring; and a core portion between said front end portion and said ink-flow adjustment portion, said core portion having a larger diameter than said front end portion such that a valve portion is formed between said core portion and said front end portion.

Claim 14

The ballpoint pen tip of claim 11, wherein said valve portion of said movable member is a tapered shoulder portion.

Claim 15

The ballpoint pen refill of claim 11, wherein said ballpoint pen tip has an ink guidance aperture, said ink guidance aperture having a seat portion on a rear end thereof, said valve portion of said movable member being arranged to engage said seat portion if said ball falls out of said ballpoint pen tip, whereby leakage from said ballpoint pen tip can be prevented.

Claim 16

The ballpoint pen tip of claim 13, wherein said valve portion of said movable member is a tapered shoulder portion.

Claim 17

The ballpoint pen refill of claim 11, wherein said ink-flow adjustment portion has a plurality of longitudinal fins thereon, said longitudinal fins extending radially outward.

Claim 18

The ballpoint pen refill of claim 15, wherein said plurality of longitudinal fins define longitudinal ink passageways around said ink flow adjustment portion.