Abstract: A heat pen may be used with an electronic cutting and/or drawing system to enable the electronic cutting and/or drawing system to use heat to define text and/or designs on a substrate. The heat pen may be coupled with a cradle of an electronic cutting and/or drawing system directly or by assembling an adapter with the heat pen. Power may be supplied to the heat pen by electrically coupling the heat pen to an external power supply, such as a power and/or communications port of the electronic cutting and/or drawing system. Electronic heated design systems and methods for modifying substrates using heat are also disclosed.

Abstract: A fountain pen comprises a hollow barrel such as can be held by a user, a nib stably attached to one end of the hollow barrel, also an ink cartridge housed internally of the hollow barrel and having a given containment volume. The cartridge is connected to the nib by way of a feed through which ink flows to the nib, and deformable by expanding at least partially between a normally undeformed first configuration, and a deformed second configuration in which the containment volume created internally is greater than the containment volume in the undeformed configuration.

Abstract: A nib of a writing instrument is made of a carbon-resin mixture obtained by mixing a plastic material with carbon fiber. An ink feed core is provided with a nib cover. The nib cover is disposed on an outer periphery of the ink feed core between the nib and the ink feed core. The nib cover is configured to closely adhere at least to an inner periphery of the nib at the tip of the nib. A space defined between the nib and the ink feed core is filled up with the nib cover. The nib is made of a carbon-resin mixture obtained by mixing a plastic material with carbon fiber. With this configuration, a nib having high wear resistance can be obtained and duration of the nib and the writing instrument can be prolonged.

Abstract: The present invention provides a direct liquid-writing instrument without ink leakage from the pen-tip even after a long period of use. Specifically, it provides a direct liquid-writing instrument having an ink-retaining part in a bellows-like shape, in which at least the ink-retaining part in a bellows-like shape is made of: 20 to 95% by mass of (A) a polyamide-based resin; and 80 to 5% by mass of (B) at least one resin selected from a styrene-based resin, an olefin-based resin, and a polyphenylene ether resin.

Abstract: A refill of a low viscosity water-based ink ballpoint pen is provided with a housing, a pen tip attached to a front end of the housing, an ink tank (4) formed inside the housing, an ink guide member guiding ink in the ink tank (4) to the pen tip, and an air passage formed between the ink tank and the pen tip in the housing and connecting the ink tank and outside of the housing. The inside of the ink tank is divided by partition walls (11) into a plurality of ink chambers arranged in the longitudinal direction, and the ink guide member is used to guide the ink in these ink chambers from the ink chambers close to the pen tip successively to the pen tip. A substantially uniform clearance (13) is provided over the entire circumferences between the outer circumferential surface of each partition wall (11) and the inner circumferential surface of the ink tank (4). A ring-shaped ink film formed at each clearance (13) is used to hold the ink in each ink chamber.

Abstract: Provided is a writing instrument comprising an ink tank, an ink holder which can hold an ink, a pen tip, an ink guiding part for guiding the ink in the ink tank to the pen tip and an ink occlusion body which can feed the ink to the ink guiding part and which has an outer skin, wherein through parts are provide in the outer skin of the ink occlusion body.

Abstract: In a liquid container, it is made possible to store liquid that is overflowed by fluctuations in atmospheric pressure and thereby to prevent liquid leaks, and the whole quantity of the stored liquid is enabled to be used. The liquid container is provided with a body having a main tank in which liquid is stored; a supply outlet, located toward the tip of the body, for supplying the liquid; a guiding portion connecting the main tank and the supply outlet to guide the liquid from the main tank to the supply outlet; and a liquid reservoir having an air flow port communicating with the exterior and a liquid flow port communicating with the main tank or the guiding portion and an overflowing liquid flow path for storing liquid overflowing the main tank. The liquid is stored farther away from the supply outlet than the liquid flow port.

Abstract: In a liquid container, it is made possible to store liquid that is overflowed by fluctuations in atmospheric pressure and thereby to prevent liquid leaks, and the whole quantity of the stored liquid is enabled to be used. The liquid container is provided with a body having a main tank in which liquid is stored; a supply outlet, located toward the tip of the body, for supplying the liquid; a guiding portion connecting the main tank and the supply outlet to guide the liquid from the main tank to the supply outlet; and a liquid reservoir having an air flow port communicating with the exterior and a liquid flow port communicating with the main tank or the guiding portion and an overflowing liquid flow path for storing liquid overflowing the main tank. The liquid is stored farther away from the supply outlet than the liquid flow port.

Abstract: In a free-ink type collector writing instrument, a collector (5) is formed with a passage hole (10) for providing commutation between the interior and the outside air so as to prevent the point assembly from being affected by the variation in inner pressure upon freezing or upon increase or decrease in pressure. At the same time, the passage hole is constructed in a shape so as not to present a stronger capillary attraction than that of an air/liquid exchanger (9) and than that of an ink feeder portion (3,6), whereby the problem of exudation leakage over time can be prevented.

Abstract: Provided is a writing instrument comprising an ink tank, an ink holder which can hold an ink, a pen tip, an ink guiding part for guiding the ink in the ink tank to the pen tip and an ink occlusion body which can feed the ink to the ink guiding part and which has an outer skin, wherein through parts are provide in the outer skin of the ink occlusion body.

Abstract: A direct-feed ballpoint writing implement includes a barrel internally provided with an ink tank, a grooved member placed in a front part of the barrel and provided with a groove for guiding air and ink, an ink feed member pressed in the grooved member, a barrel tip fixedly joined to a front end part of the grooved member, a ball holder inserted in the barrel tip and put on a front end part of the ink feed member, and a ball held in a front end part of the ball holder. A compression spring may be extended at least between the ink feed member and the ball in the ball holder.

Abstract: A highly durable conical nib is provided which also realizes a significant improvement in a nib productivity and a significant cost reduction. The conical nib comprises: a plurality of separated combtooth pieces being able to converge progressively toward front ends thereof and combine to form a virtually conical shape and that the front ends thereof combine to form a virtually spherical shape; a holding member capable of arranging the combtooth pieces along a circumference; and a converging member capable of converging these combtooth pieces; wherein the plurality of separated combtooth pieces are assembled by the holding member and the converging member, both separate from the combtooth pieces, into a conical nib having a writing tip at the front end thereof and an ink feeding path between each combtooth piece.

Abstract: A writing instrument has a housing containing an ink reservoir. The writing instrument further has a writing nib in communication with one (or both) end of the ink reservoir by an ink induction device. In connection with the ink reservoir, there is also at least one set of pressure balance system. The pressure balance system includes a nano hydrophobic venting material that allows air to flow in and out of the reservoir to compensate pressure differential between ambient atmosphere and the interior of the ink reservoir, while prevents ink to flow from the ink reservoir to the atmosphere.

Abstract: In a free-ink type collector writing instrument, a collector (5) is formed with a passage hole (10) for providing commutation between the interior and the outside air so as to prevent the point assembly from being affected by the variation in inner pressure upon freezing or upon increase or decrease in pressure. At the same time, the passage hole is constructed in a shape so as not to present a stronger capillary attraction than that of an air/liquid exchanger (9) and than that of an ink feeder portion (3,6), whereby the problem of exudation leakage over time can be prevented.

Abstract: A collector type writing instrument which is formed with a sectioning portion for substantially separating its ink tank and a snorkel having a tubular vent portion for establishing air communication between the front and rear spaces divided by the sectioning portion, wherein at least one ink conduit of a size smaller than that of the vent portion is formed in the sectioning portion. Further, a clearance portion allowing for ink and air bubbles to move therethrough is provided between the collector and snorkel. In addition, the parts present from the sectioning portion to the rear end of the collector are laid out so that ink will be able to spread and wet the surfaces of the parts other than the ink tank. It is also preferable that the end of the tubular vent portion of the snorkel is cut so as to enlarge the opening.

Abstract: In a writing instrument with a collector of the present invention, an ink absorber made up of a fabric sliver etc., capable of keeping ink therein is disposed inside the ink tank and is connected to the center core, longitudinal groove or the like as an ink feeder portion. The ink absorber is adapted to have a length at least reaching to a position more rearwards than the approximate center of the ink tank and has an outside diameter that is sized to be smaller than the inside diameter of the ink tank so as to create a space around itself for permitting free-state ink to move freely while the collector has a lead portion for establishing connection enabling ink to be led from the ink absorber to the air/liquid exchanger. Specifically, the lead portion of the collector may be configured of a projecting portion directly inserted into and connected with the ink absorber and a lead channel formed on the projecting portion.

Abstract: In a free-ink type collector writing instrument, the collector is formed with a partitioning portion for substantially shutting off the ink tank from the outside air, auxiliary retaining grooves are formed on the ink tank side with respect to the air/liquid exchanger of the partitioning portion while main retaining grooves are formed on the front side with respect to the air/liquid exchanger of the partitioning portion, a wide groove formed across the auxiliary retaining grooves for connecting the air/liquid exchanger and the ink tank is formed with a narrow groove extending from the air/liquid exchanger side to the ink tank side and lateral grooves capable of leading ink into the auxiliary retaining grooves. It is further effective if the capacity ‘ie’ of the auxiliary retaining grooves and the capacity ‘is’ of the main retaining grooves are designed so as to satisfy a relation ‘is>ie>0.05·is’ or if effective partitioning portion grooves are formed.

Abstract: A writing implement for preventing ink from leaking out from a front end of a tip by absorbing much of a change in pressure inside an ink tank, the implement being a direct liquid type writing implement having an ink tank and an ink flowing portion connecting the ink tank and a writing end, a temporary ink reserve part for temporarily holding ink and an air supplying portion for supplying air to the temporary ink reserve part, the temporary ink reserve part being constituted by a temporary ink reserve groove and an ink guide groove, an ink introducing groove at a vicinity of the ink tank constituting a portion of the ink guide groove, a distance from the writing end to an end portion of the temporary ink reserve groove on its ink tank side being larger than a distance from the writing end to the ink introducing groove.

Abstract: The present invention provides a collector type writing instrument including: a collector for temporarily storing ink therein upon a change in inter pressure, a sectioning portion for substantially separating its ink tank for storing ink, and a snorkel having a vent portion for establishing air communication between the front and rear spaces divided by the sectioning portion or an ink absorber for reducing the inner tank volume, wherein the snorkel or the cladding of the ink absorber is molded of the same material as the collector or the ink tank is or is subjected to the same wettability reforming treatment as the collector or the ink tank is.

Abstract: In a writing instrument with a collector of the present invention, an ink absorber made up of a fabric sliver etc., capable of keeping ink therein is disposed inside the ink tank and is connected to the center core, longitudinal groove or the like as an ink feeder portion. The ink absorber is adapted to have a length at least reaching to a position more rearwards than the approximate center of the ink tank and has an outside diameter that is sized to be smaller than the inside diameter of the ink tank so as to create a space around itself for permitting free-state ink to move freely while the collector has a lead portion for establishing connection enabling ink to be led from the ink absorber to the air/liquid exchanger. Specifically, the lead portion of the collector may be configured of a projecting portion directly inserted into and connected with the ink absorber and a lead channel formed on the projecting portion.

Abstract: The object is to provide a writing instrument in which a large-diametric ink retaining portion with narrow grooves in width and still capable of securing a large enough air channel can be formed so that the replacement of the sufficient amount of air can be effected between the ink retaining portion and the outside air. To achieve this, in an ink retaining portion (12), a plurality of cutouts (32) are formed so that each cutout (32) is formed to a right angle direction with respect to a center line (16a) of the sheet element (16) with a length equal to or greater than half the radius (R) (A≧(R/2), B≧(R/2)) and that one end of the cutout (32) is extended to the periphery.

Abstract: Writing and metering device with an ink supply chamber (22), an ink guide with a capillary ink regulator (20) and with a ventilation channel with a semi-permeable seal (30), a first non-capillary space (28) and a second non-capillary space (33). The second non-caplliary space (33) is connected to the ink supply chamber (22) by at least one capillary (32a and/or 32b). To reduce ink losses a labyrinth vent (26) can additionally be provided in the ventilation channel.

Abstract: In a writing implement having a feeder core for feeding ink in an ink tank to a pen tip and an ink collector in which a plurality of comb-tooth like elements formed with an air-liquid exchange groove are arranged at intervals in a feeder core axial direction, an ink holding plate is provided so as to face a rear end face of the ink collector in such a manner as to form a gap for holding the ink in the ink tank by means of the capillary phenomenon between the ink holding plate and the rear end face, and also a plurality of air exchange grooves for flowing and discharging ink of an amount responding to a change in pressure in the ink tank into and from grooves between the comb-tooth like elements are formed between an outer edge portion of the comb-tooth like element and a feeder core contact portion.

Abstract: In a free-ink type collector writing instrument, the collector is formed with a partitioning portion for substantially shutting off the ink tank from the outside air, auxiliary retaining grooves are formed on the ink tank side with respect to the air/liquid exchanger of the partitioning portion while main retaining grooves are formed on the front side with respect to the air/liquid exchanger of the partitioning portion, a wide groove formed across the auxiliary retaining grooves for connecting the air/liquid exchanger and the ink tank is formed with a narrow groove extending from the air/liquid exchanger side to the ink tank side and lateral grooves capable of leading ink into the auxiliary retaining grooves. It is further effective if the capacity ‘ie’ of the auxiliary retaining grooves and the capacity ‘is’ of the main retaining grooves are designed so as to satisfy a relation ‘is>ie>0.05·is’ or if effective partitioning portion grooves are formed.

Abstract: A free-ink type writing instrument includes: an ink tank for holding ink; a temporary ink collector for temporarily retaining the ink flowing out from the ink tank; a partitioning wall separating the ink tank and the temporary ink collector; and a pen core disposed from the ink tank, penetrating through the partitioning wall and the ink collector so as to allow ink to flow out from the ink tank, and is characterized in that the storage volume Vc of the ink collector and the ink tank volume Vo satisfy the relation Vc≧0.18Vo.

Abstract: A free-ink type writing instrument includes: an ink tank for holding ink; a temporary ink collector for temporarily retaining the ink flowing out from the ink tank; a partitioning wall separating the ink tank and the temporary ink collector; and a pen core disposed from the ink tank, penetrating through the partitioning wall and the ink collector so as to allow ink to flow out from the ink tank, and is characterized in that the storage volume Vc of the ink collector and the ink tank volume Vo satisfy the relation Vc≧0.18 Vo.

Abstract: Writing and metering device with an ink supply chamber (22), an ink guide with a capillary ink regulator (20) and with a ventilation channel with a semi-permeable seal (30), a first non-capillary space (28) and a second non-capillary space (33). The second non-capillary space (33) is connected to the ink supply chamber (22) by at least one capillary (32a and/or 32b). To reduce ink losses a labyrinth vent (26) can additionally be provided in the ventilation channel.

Abstract: An inexpensive writing pen for low viscosity liquid inks and formed with an internal ink reservoir and a capillary system for admitting air into the reservoir. The ink reservoir is formed directly by the walls of the pen body, which form an internal cavity. Transfer of heat from the writer's hand into the region of the ink reservoir is inhibited by providing projection elements and intervening air spaces, which form the effective outer surface of the pen body. Preferably, the material of the pen body extends substantially above the upper limits of the internal ink reservoir, and is provided in those upper areas with similar projections and spaces, facilitating transfer of heat from the pen body into the ambient. The arrangement minimizes variations in the pen characteristics resulting from transfer of heat from the user's hand, which can become relatively more acute as the volume of air within the ink reservoir increases as a result of ink consumption.

Abstract: An application liquid reservoir (collector) reserves application liquid in the vicinity of an application liquid guide that is interposed between an application liquid cartridge and an applicator. The application liquid reservoir includes a cylinder having an inner hole to receive an ink guide and fins projecting from the cylinder. The fins stand parallel to each other and perpendicular to an axial direction of the inner hole at predetermined intervals, with annular application liquid reserving slots being defined between respective adjacent two fins such that the application liquid reserving slots are set to be narrower in part.

Abstract: A collector for adjusting internal pressure of a writing implement offers improvements in deficiency prevention performance such as the capability of preventing ink leakage from occurring due to influence of the ambient pressure being varied during usage or when its cap is put on and off, the capability of preventing ink from erupting or leaking forward when the implement has been stored at a shop for a long period, and which still provides smooth writing comfort during writing. A collector (106) introduces ink through an ink channel (114) by the function of capillary action and temporarily holds ink in ink retaining grooves (113) and establishes air passage in the axial direction and radial direction by the combination of the air channel (115) and retaining grooves (113). The air channel is continuously formed so as to zigzag with a multiple number of turns with respect to axial direction of collector (106) by way of air channel parts (115a, 115b, 115c and 115d) and connecting passages (122a, 122b and 122c).

Abstract: A writing implement with an ink collector is able to prevent ink soiling at the pen tip even when the writing implement has been left under an atmosphere of 0° C. or below, at which the ink inside the writing implement will begin freezing and can be assembled by a simple assembling machine with its productivity improved. This writing implement with an ink collector is a direct ink storage type writing implement having an ink chamber 2 disposed at the rear part of a barrel cylinder 1 for directly storing the ink and an ink collector 5 mounted at the front part of barrel cylinder 2 and is characterized in that ink collector 5 is formed with a passage hole 6 therein in which an ink conduit core 8 for conveying the ink from ink chamber 2 to a pen tip 10 is provided while the flank of ink collector 5 is formed with air holes 7 that communicate with passage hole 6.

Abstract: An application liquid reservoir (collector) that is made to achieve an object of the invention is the application liquid reservoir which reserves the application liquid in the vicinity of an application liquid guide that is interposed between an application liquid cartridge and an applicator. Said application liquid reservoir is comprised of a cylinder having an inner hole to receive an ink guide and fin means projecting from the said cylinder. Said fin means includes a plurality of fins that stand parallel to axial direction of the inner hole at predetermined intervals, said annular application liquid reserving slots being defined between said respective adjacent two fins such that said application liquid reserving slot are set to be narrower in part.

Abstract: A writing instrument comprising a pen point receiver, a pen point and an ink introducing core member. The tip end portion of the pen point is formed to curve downwardly towards the tip end writing portion with respect to the base end portion of the pen point.

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.

Abstract: A penpoint has a base portion and a plurality of comb-tooth pieces and a converging member fitted over the portion of the penpoint body between the base portion and the comb-tooth pieces. The uniform pressure of the converging member converges the comb-tooth pieces front ends into an undistorted hemispheric writing portion having ink passages between the adjoining comb-tooth pieces. When the penpoint is pressed against paper with the pen axis inclined, the front ends of the comb-tooth pieces shift and elastically deform to expand the outer diameter of the hemispheric portion. When pressure is relieved it returns to its original hemispherical shape. The thickness of strokes varies according to writing pressure. The penpoint can write in any direction.

Abstract: An integrated feather ink pen enables one to enjoy all of the benefits of the historic form of writing without the disadvantages. A shaped grip provides a comfortable means of operating the pen. A feather is attached to the grip to provide balance and a reservoir for ink or a compartment for an ink cartridge. The grip, together with an ink transport mechanism, serve to bind the nib to the feather. The ink transport mechanism is an ink feeder tube or a fibrous filament. Alternatively, the nib is dipped in ink.

Abstract: A writing instrument has an ink reservoir, a nib and a feeder which temporarily stores ink which is pushed out of or pulled into the ink reservoir. The ink reservoir communicates with the nib through an ink supplying passage. The feeder chamber communicates with the atmosphere through an atmosphere communicating passage and with the ink reservoir through a capillary flow passage. The cross-sectional area of the capillary flow passage is small enough to hold ink in the capillary flow passage due to a surface tension of the ink. When the pressure in the ink reservoir due to a temperature change, etc., ink flows in the feeder chamber through the capillary flow passage or is returned from the feeder chamber to the ink reservoir. Since the feeder chamber is hollow, its volume is large and has a simple structure, the feeder can be manufactured easily. A low flow resistance of the capillary flow passage provides good response for compensation for a pressure change.

Abstract: A penpoint assembly includes a penpoint which is made of a metal plate cut off at both side edges to form a taper toward the writing tip. A slit is provided extending from the front end of the writing tip to the vicinity of the rear end of the writing tip along the center line of the penpoint. The penpoint is bent at the writing tip to form small bent projections at both sides of the slit, the bent portion surrounding a small space. An ink guide core extends under the slit and communicates at the tapered portion of the ink guide core with the slit. A support member supports the ink guide core and penpoint. A writing instrument includes the penpoint assembly, the support member being integrally formed with an ink flow regulating portion, so that ink in an ink storage member in the rear portion of a penholder is guided to the writing tip through the ink guide core.

Abstract: A reservoir pen includes a valve operated by the pen nib (4) to allow ink to pass to the nib, the ink flow rate being controlled by a flow restricting device (8) located between a primary ink reservoir chamber (2) enclosed within the pen barrel (1) and a secondary ink reservoir chamber (6) of much smaller capacity from which an ink channel (10) leads to the valve. The device (8) is a length of an extruded rod of microporous plastics. The nib is pressed towards the feed bar (3) by one spring element (21) and the valve member (12) which cooperates with a seat defined by the feed bar is urged to its closed position by another spring element (28). The rear end of the primary ink chamber (2) is closed by a grease plug comprising a mass of grease and a skeletal reinforcing frame.

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 supply system is provided for a device that operates with capillary forces and is used to apply liquids. The system includes receptacles that accommodate the liquid and are closed off relative to the atmosphere. Also provided is an application element that communicates with the receptacles via a feed mechanism and serves for the application of the liquid, for which purpose the application element has a discharge. Each of the receptacles is provided with an inlet and an outlet, with the receptacles being interconnected in the manner of a series connection by having the outlet of one receptacle communicate with the inlet of another receptacle. The capillarity of the inlets and outlets is greater than the capillarity of the receptacles in the vicinity of the inlets and outlets thereof, and is less than the capillarity of the discharge of the application element.

Abstract: A multiangular pen comprising a multiangular pen nib; a pen core having holder pieces fitted the surface of the pen nib and a rod-like connector formed integral to the base end of the holder pieces, said pen core being made by tamping and molding a fibers material, having liquid permeability and serving to hold the pen nib with its holder pieces fitted the surface of the pen nib; and a penholder for housing a pen nib assembly of the pen nib and the pen core; wherein the body of said pen core is inserted into the ink holding member.

Abstract: A multiangular pen comprising a multiangular pen nib; a pen core having holder pieces fitted the surface of the pen nib and a rod-like connector formed integral to the base end of the holder pieces, said pen core being made by tamping and molding a fibers material, having liquid permeability and serving to hold the pen nib with its holder pieces fitted the surface of the pen nib; and a penholder for housing a pen nib assembly of the pen nib and the pen core; wherein the body of said pen core is inserted into the ink holding member.

Abstract: This invention presents a multiangular pen in which a pen nib is inserted and housed in a pen nib housing hole provided on a pen nib holder sleeve. Further, a push sleeve having a guide hole extending in its longitudinal direction and communicating with the pen nib housing hole is fitted into the pen nib housing hole at the back end side of the pen nib holder sleeve to support the pen nib. In the guide hole and the pen nib housing hole, an ink introducing core is inserted.

Abstract: In a writing instrument including an ink reservoir and an air hole, the air hole is spanned by a barrier formed as a porous non-absorbent ink repellent membrane of substantially uniform pore size. The barrier is non-porously sealed, for example by direct heating or ultrasonic welding, along its entire periphery to the wall of the air hole, the barrier allowing air to pass freely therethrough in both directions, but preventing escape of ink therethrough and therearound. The barrier is preferably formed of polytetrafluoroethylene with a pore radius of not more than 10 .mu.m and a thickness of not more than 200 .mu.m. The ink for use in the writing instrument preferably has a surface tension of not less than 30 mN m.sup.-1, a viscosity of not more than 10 cp and a wetting angle with the barrier of not less than 100.degree..

Abstract: A pen core for a writing instrument, particularly, for use in a recorder in which writing must be continuously carried out over long periods using a relatively small ink supply. The instrument has an ink conducting core for conducting ink to a writing member, and a barrel with an ink reservoir, the barrel being fitted on the outer wall of the pen core body. An annular groove in the form of a single continuous passageway is formed in the outer wall of the pen core body, the annular groove having a front end connected to an ink sucking groove, which is in turn communicated with the ink conducting core. An air passageway having a front end communicated with an air hole and a rear end communicated with the rear end of the annular groove is formed in the outer wall of the pen core body in such a manner that the air passageway does not cross the annular groove.

Abstract: A writing instrument of an extremely simple structure in which stored ink previously extruded upon increase of the internal pressure of an ink chamber is subsequently sucked up by decrease of the internal pressure of the ink chamber and returned to the ink chamber, thereby preventing the outputting of ink drops in a downward orientation of pen, particularly when a large amount of ink is stored.