US 6,261,019 B1Granted

Ball point pen

AssigneeMitsubishi Pencil Company, Limited

InventorKazuhiko Furukawa

Life of this patent

Estimating the term…

Loading patent…

Abstract

In a free-ink type low-viscosity water-based ball point pen, the low viscosity water based ink 17 contains 40% or more of water as a main solvent and has a viscosity of 1.5 cps to 60 cps at a normal temperature. A collector 6 has a slender, slit-like ink groove 16 and an air vent groove 14. In a zone covering from a collector air-venting portion 15 to an outside air with which the collector air-venting portion 15 is communicated the collector 6 has a mouth piece 5 having provided therein the thin and elongate air vent groove 14. The maximum amount of ink stored in the collector 6 is made 15% or more of the capacity of an ink tank 9. The ink tank 9 is made detachable and has its main body formed of transparent or semi-transparent synthetic resin, the main body therefore enabling a residual amount of ink 17 to be visually recognizable from outside.

Claims11

Dependent claims

A water-based ball point pen comprising:

a holder for holding a ball constituting a writing portion at its tip,
an ink tank for directly storing ink therein,
a collector that adjusts the internal pressure of the pen interior and that is composed of a plurality of vane-like adjuster members utilizing a capillary action phenomenon, and a center core for guiding ink from an ink accommodation tube to the ball constituting the writing portion, wherein the ink is a low-viscosity water-based ink that contains 40% or more of water as a main solvent and the viscosity thereof is from 1.5 to 60 cps at normal temperature, wherein the collector has a slender, slit-like longitudinal groove for ink and an air communication groove, while between the air communication groove of the collector and the outside air with which the air communication groove is communicated there is provided a mouth piece having disposed of a slender, elongated air flow channel with the use of one of a single piece of part and combined pieces of parts for suppressing the volatilization of the ink from the pen body, and wherein the ink tank located behind the collector is detachably mounted, wherein the maximum amount of ink accommodated in the collector is made 12% or more of the volume of the ink tank, while the ink tank has its main body formed of one of a transparent synthetic resin and a semi-transparent synthetic resin, enabling a residual amount of ink to be visually recognizable from outside.

A water-based ball point pen comprising:

a holder for holding a ball constituting a writing portion at its tip;
an ink tank for directly storing ink therein;
a collector for adjusting internal pressure of an interior of the pen, the collector including a plurality of vane-like adjuster members utilizing a capillary action phenomenon;
a center core for guiding ink from an ink accommodation tube to the ball constituting the writing portion;
and wherein
the ink is a low-viscosity water-based ink that contains 40% or more of water as a main solvent and the viscosity thereof is from 1.5 to 60 cps at normal temperature;
the collector having a slender, slit-like ink longitudinal groove for ink and an air communication groove, a mouth piece being provided between the air communication groove and outside air;
the maximum amount of ink accommodated in the collector being made 12% or more of a volume of the ink tank, while the ink tank has a main body formed of one of a transparent synthetic resin and a semi-transparent synthetic resin, enabling a residual amount of ink to be visually recognizable from outside;
and
a neutral to alkaline ink of PH 6 to 11 is stored in the ink tank, and wherein the ink tank, mouth piece and holder occupy at least 95% of an outer surface area of an outer surface portion of a whole outer surface of the pen which is in contact with outside air, excluding an area occupied by the air hole, each of the ink tank, mouth piece, and holder being constructed of a synthetic resin part formed of a material which has a water absorption rate of 0.2% or less, has anti-hydrozability, and is free of ester bonds in its composition and includes one of a metallic part having water resistance and an inorganic material having non-water permeability properties.

7 more elements

Dependencies are inferred from the claim text.