US3334616A - Ink utilization in writing instruments - Google Patents

Ink utilization in writing instruments Download PDF

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Publication number
US3334616A
US3334616A US498362A US49836265A US3334616A US 3334616 A US3334616 A US 3334616A US 498362 A US498362 A US 498362A US 49836265 A US49836265 A US 49836265A US 3334616 A US3334616 A US 3334616A
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US
United States
Prior art keywords
ink
reservoir
writing
cartridge
follower
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US498362A
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English (en)
Inventor
Gerald R Urquhart
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Paper Mate Manufacturing Co
Original Assignee
Paper Mate Manufacturing Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Paper Mate Manufacturing Co filed Critical Paper Mate Manufacturing Co
Priority to US498362A priority Critical patent/US3334616A/en
Priority to GB46384/66A priority patent/GB1144788A/en
Priority to ES0332441A priority patent/ES332441A1/es
Priority to SE14329/66A priority patent/SE320910B/xx
Priority to DE19661511380 priority patent/DE1511380A1/de
Priority to AU13826/66A priority patent/AU417459B2/en
Priority to CH1642266A priority patent/CH453949A/de
Priority to BE692484D priority patent/BE692484A/xx
Application granted granted Critical
Publication of US3334616A publication Critical patent/US3334616A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B43—WRITING OR DRAWING IMPLEMENTS; BUREAU ACCESSORIES
    • B43K—IMPLEMENTS FOR WRITING OR DRAWING
    • B43K7/00—Ball-point pens
    • B43K7/10—Arrangements for feeding ink to the ball points
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B43—WRITING OR DRAWING IMPLEMENTS; BUREAU ACCESSORIES
    • B43K—IMPLEMENTS FOR WRITING OR DRAWING
    • B43K7/00—Ball-point pens
    • B43K7/02—Ink reservoirs; Ink cartridges
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B43—WRITING OR DRAWING IMPLEMENTS; BUREAU ACCESSORIES
    • B43K—IMPLEMENTS FOR WRITING OR DRAWING
    • B43K7/00—Ball-point pens
    • B43K7/02—Ink reservoirs; Ink cartridges
    • B43K7/03—Ink reservoirs; Ink cartridges pressurised, e.g. by gas
    • B43K7/035—Ink reservoirs; Ink cartridges pressurised, e.g. by gas the gas acting on a piston

Definitions

  • Normal ball point writing instruments generally include a tubular cartridge or reservoir, the forward end thereof being in communication with or at least attached to a writing tip, including a socket in which a ball is rotatably held.
  • the cartridge is filled with a suitable ink and the rear end of the cartridge is generally placed in communication with the atmosphere, although in some instances a gas under pressure may be superimposed upon the surface of the ink in the cartridge.
  • a gas under pressure may be superimposed upon the surface of the ink in the cartridge.
  • back leakage since ball point writing instruments of this type are sometimes carried in the pocket with the writing tip pointed upwardly or permitted to rest in a horizontal position for protracted periods of time, there is tendency for the ink to ooze out of the open end (referred to as back leakage"). Also, when the rear end of the cartridge is enclosed and supplied with a source of gas under pressure, the ink may move rearwardly towards the closed end and entrap bubbles of gas within the body of ink so that subsequent utilization of the pen is not very satisfactory since bubbles of air in the very small diameter channels leading to the ball socket will interrupt the flow of ink to the socket and cause the pen to discontinue writing. Back leakage is undesirable since it may stain clothing, reduce writing ability, etc.
  • the interruption in writ ing function is not a clear-cut termination but is often ac differentiated by a decrease in the amount of ink made available to the writing ball causing the writing trace to become indistinct or interrupted in part, thereby causing the writer to feel that the instrument is malfunctioning and has not been depleted of its ink.
  • the presentinvention is directed to this problem and to means and methods of eliminating the problem.
  • the invention distinguishes from prior practices in that instead of employing a unitary follower, such a body of grease, there is now employed a viscous or viscoplastic follower in contact with the walls of the reservoir and with a centrally disposed elongated virtually rigid element which interrupts the previously continuous contact between grease and top ink surface.
  • the central element preferably also extends through and iuterrupts the continuity of the top surface of the body of viscous follower, although the existence of a thin film over the element is permissible.
  • the assembly of viscous follower and element is herein referred to as a follower assembly since it moves downwardly with the surface of the ink body as the latter is depleted during writing.
  • the element may be cylindrical, or it may be axially bored; when so bored, the axial port may contain additional viscous follower or a loosely fitting pin with grease between the pin and bore wall in the element.
  • An object of the present invention is to disclose means and methods whereby substantially the entire volume of ink initially charged into a cartridge or reser' voir of a writing instrument is capable of being utilized in writing with such instrument, and no appreciable quantity of ink is wasted or remains incapable: of use.
  • Another object is to disclose means and methods for effectively utilizing the entire volume of ink, initially charged into a cartridge or reservoir of a ball point type pen, in performing normal writing functions without objectionable interruptions of such writing function when the ink charge has been reduced to a minor percentage of the initial charge.
  • a still further object is to insure a termination of the writing function only when the body of ink initially charged into the writing instrument has been depleted, thereby eliminating the false interruptions of writing function caused by premature impairment of ink movement to the ball point tip, which false movement generally occurs in prior writing instruments of this type and constitutes a source of annoyance.
  • FIG. 1 is a representation of a writing instrument including one form of cartridge (portions of the body being broken away) whereby the relationship of the cartridge to the pen body and retraction mechanism can be readily understood.
  • FIG. 2 is an enlarged side view of a portion of a cartridge, the wall of the cartridge being partly broken away, illustrating one form of composite follower assembly embodying the present invention.
  • FIG. 3 illustrates the position of the follower assembly of FIG. 2 shortly after it had reached the constriction in the cartridge.
  • FIG. 4 is an enlarged axial section of a portion of a cartridge illustrating another modified form of follower assembly utilizing the present invention, the follower as sembly having reached a constriction in the reservoir.
  • FIG. 5 in a transverse section of a cartridge containing a follower as in FIG. 4, showing a plan View of the follower assembly.
  • FIG. 6 is an axial section through a portion of a cartridge including a still further modification of a follower assembly.
  • FIG. 1 somewhat diagrammatically represents a complete writing instrument of the ball point type including an outer barrel composed of a forward barrel section 1 and a removable cap portion 2 which normally includes a retraction mechanism generally indicated at 3 and often actuated by a rearwardly extending plunger 4. Since various retraction mechanisms are known in the art, details are not shown.
  • Removable positioned within the pen body or barrel is a cartridge or ink reservoir 10 provided with a writing tip 11 which is capable of being projected from or retracted into the lower end of the barrel by the retracting mechanism 3. In most instances retraction is facilitated by the action of a spring bearing against an abutment formed on the interior surface of the barrel and against an enlargement or shoulder formed in the cartridge 10.
  • the cartridge illustrated in FIG. 1 includes an upper reservoir section 12 of relatively large diameter and an auxiliary tubular reservoir 13 of smaller internal diameter into which the tip 11 extends.
  • the tip 11 (as more clearly shown in FIG. 3) includes very small ink channels 14 leading to a socket containing a rotatable ball 15.
  • the rear end of the cartridge may be provided with a plug having a rearwardly extending projection 16 which is axially bored to permit air to enter the rear part of the cartridge.
  • a body of ink is contained within the cartridge, such body of ink being continuous in that it fills the enlarged or main reservoir section 12, the smaller reservoir 13 and the channel 14, thereby insuring a continuous, unbroken supply of ink to the writing ball 15.
  • a viscous follower or small body of grease generally indicated at 18.
  • the body of ink within the reservoir is depleted and the grease follower 18, being in contact with the top surface of the ink as well as with the walls of the cartridge, follows the ink as its level drops.
  • the body of grease 18 maintains its coherence and integrity and is preferably insoluble in and immiscible with the ink; it is also preferably of a non-drying character.
  • viscous follower materials having a gel strength or yield strength on the order of 800 to 1100 dyne per square centimeter in order to prevent the material from shearing or being excessively deformed when a writing instrument of this type is in an inverted or horizontal position for a protracted period of time (as during storage).
  • writing ability of the instrument becomes unsatisfactory; the supply of ink to the writing ball is interrupted; the user is annoyed since the interruption may be momentary or the trace left by the ball becomes weak for a short period of time and then a minute additional quantity of ink manages to get through the passageways so as to permit writing for another minute or two, and then becomes interrupted again.
  • the writing ability decreases to zero and the remaining portion of ink contained in the auxiliary reservoir section 13 and channels of the tip is rendered useless and wasted.
  • FIG. 2 is an enlarged side elevation partly in section of the same general type of cartridge as that illustrated in FIG. 1, but equipped with a follower assembly which provides a solution to the problem referred to hereinabove.
  • the follower assembly includes a relatively rigid or solid smooth-surfaced tubular element 20 positioned within a body of grease 28 and interrupting the continuity of such body inasmuch as the grease surrounds the tubular element 21 thereby spacing it from the internal walls of reservoir section 12 and also fills the central or axial bore 21 within the tubular element 20.
  • the grease 28 does not extend completely across from wall to Wall within the cartridge since the upper end of element 20 is not covered by the grease but extends thereabove.
  • the lower and conical end 22 of the element 20 preferably extends below the body of grease into the ink indicated at 30.
  • the outer diameter of element 20 is larger than the internal diameter of section 13 of the cartridge, but materially smaller than the internal diameter of main reservoir 12.
  • the element 20 may be made of any thermoplastic or thermosetting resinous composition which may include any desired polymer or copolymer capable of producing a relatively solid or rigid, preferably smooth-surfaced element having a specific gravity lower than that of the ink and greater than that of the grease.
  • inks commonly employed in ball point pens may have a specific gravity of from about 1.100 to 1.185 and the viscous follower material may have a specific gravity of from about 0.90 to about 0.95.
  • a polyethylene, polyvinyl, polyamide or polystyrene follower element 20 having a specific gravity of from about 0.97 to about 1.09 may be employed.
  • FIG. 3 illustrates the position of such a follower shortly after it has reached the conical or tapering section 17 of the cartridge and the ink level has dropped until its surface is at or below the top of the tubular auxiliary reservoir section 13, or where said section merges into the conical restriction 17.
  • the lower annular edge of the element 20 is tapered so as to contact the conical wall 17 and position its smooth axial bore 21 in substantial alignment with the axis of the smaller tubular reservoir 13.
  • the body of grease contained within the bore 21 of the element 20 will emerge from such bore and fol low the body of ink 30 as indicated at 28 in FIG. 3.
  • this section of grease 28 although it may have a high shear strength, is not subject to shear or deformation and readily slides along the surfaces of the bore 21 in the element 20 so as to readily follow the body of ink down through the small diameter reservoir 13.
  • a boundary layer flow appears to take place when the core of grease leaves the solid element to follow the body of ink into the reservoir portion 13, writing terminating sharply when the grease reaches the tip, particularly when bore 21 is smaller than the internal diameter of 13.
  • FIGS. 4 and 5 refer to a modified form of follower assembly wherein the annular or hollow cylindrically formed plastic element 20 now loosely and slidably contains another plastic element 23 in the form of a smoothsurfaced solid cylinder or pin.
  • the grease 28 surrounds the element 20 and is also contained between the pin 23 and the inner bore 21 of element 20.
  • the follower assembly is shown when it reaches the constriction, contacts the conical walls of the section 17 of the cartridge and the ink level now starts to descend through the auxiliary reservoir 13.
  • the diameter of the inner bore 21 of element 20 is very slightly larger than and not appreciably smaller than the inner diameter of the section 13 of the cartridge; the outer diameter of the pin 23 is smaller than the inner diameter of section 13; a radial clearance of between about 0.01 to 0.03 between the inner bore 21 and outer surface of pin 23 provides adequate space for grease therebetween and proper functioning.
  • the grease-encased pin 23 slides out of the bore 21 of element 20 (which has been stopped by the conical constriction 17 of the cartridge) and follows the body of ink until such pin 23 reaches the dash-lined position, 23
  • FIG. 6 illustrates a modification wherein the rigid element of the follower assembly is an elongated element having an upper, virtually cylindrical portion 24 whose greatest diameter is slightly smaller than the inner diameter of reservoir section 13, and an axially aligned lower extension 25 of even smaller diameter, the lowermost portion 26 of such extension being adapted to at least partially enter the writing tip 11 and channel 14 therein.
  • Suitable inclined or conical surface areas may interconnect the upper portion 24 with the lower portions of smaller diameter whereby the element is provided with a smooth, unrecessed surface.
  • This form of follower element desirably has a head portion 24 having a volumetric displacement at least equal to (and preferably somewhat greater than) that of its lower extension; the length of section 24 is preferably from 20% to 40% (or even 50%) of the length of the entire element.
  • FIG. 6 exemplifies the solid plug element of a follower assembly; a plug element of similar external contours but having a small axial bore (say about 0.02 inch in diameter) can also be used, and any grease contained in the upper portion of such bore immediately after the follower assembly is installed above a body of ink in a reservoir cartridge will, after the element reaches its lower limit of travel in the cartridge, move downwardly through said bore to follow the ink to the writing tip and cause an abrupt termination of writing when the supply of ink is exhausted.
  • the follower assembly of this invention (in its various forms) is placed in position and in cooperative contact with the contact with the upper surface of ink in a cartridge or reservoir, preferably after ink has been charged into a reservoir and preferably after such ink-filled reservoir has been subjected to preliminary centrifuging whereby all channels and ink passageways to the ball socket have been filled with ink and air bubbles (if any) have been eliminated. In many cases, preliminary centrifuging is not necessary. A measured amount of viscous follower material and the solid follower element or elements are then inserted into the rear of the cartridge and the cartridge subjected to centrifugal forces to insure proper contact between the follower assembly and the surface of the ink.
  • the quantity of viscous material employed is preferably insuflicient to form a materially thick layer extending over the upper end of the solid follower component after such final centrifuging.
  • Various greases may be used, generally composed of an oleaginous component (non-drying viscous oil or silicone) with or without a soap or thickening agent such as a colloidal material or salt of a fatty acid (such as aluminum stearate, zinc stearate, etc.).
  • a soap or thickening agent such as a colloidal material or salt of a fatty acid (such as aluminum stearate, zinc stearate, etc.).
  • Other additives such as oxidation inhibitors, colloidals fillers, gel formers, etc.
  • the plastic, viscous, or visco-elastic follower employed should preferably not exhibit a marked ability of spreading upon the inner surfaces of the reservoir: such tendency may be reduced bysuitablechange in composition or pre-treatment of surfaces of the cartridge.
  • the grease heretofore employed has had a gel strength of yield strength of between about 800 to about 1100 or even 1250 dyne per square centimeter
  • the grease employed in the follower assemblies of this invention may have a lower yield strength (as low as 250 dyne per square centimeter) even when the assembly is used in writing instruments having a main reservoir of 0.2 inch internal diameter.
  • the internal diameter of large capacity reservoirs of ball point pens is on the order of 0.170 inch and of normal reservoirs on the order of 0.100 inch. It is to be understood that, if desired, the follower assemblies of this invention may be used in normal. reservoirs.
  • the gel strength of viscous follower materials adapted for use in the method and follower assembly of this invention may also be very much higher, i.e., a gel strength on the order of 22002500 dyne per square cm. can be used in a follower assembly of this invention, whereas such high gel strength follower material would be unusable alone.
  • the gel strength of a grease may be determined in several Ways, one of which involves the breaking strength of a column of grease.
  • a syringe is loaded with a grease to be tested, the syringe being fitted with a 13 gauge needle and the needle filled with grease from the syringe. It is desirable to allow the grease to age for a period of time to permit it to recover from the work softening that sometimes occurs during filling of the needle.
  • the syringe is then mounted vertically, needle down, over a weighed receiver. Grease is extruded l0 mgs. at a time at one minute intervals until the pendant grease column breaks or shows that it would break.
  • the column is in the latter case allowed to break under its own weight, even when several minutes are required for the breaking process to go to completion.
  • the grease caught in the receiver is weighed to determine the tension on the grease column when it broke. From this tension and the inside diameter of the needle, the breaking strength in dynes per square centimeter is calculated.
  • Relative gel strength can also be determined by extruding the grease from a tube of larger diameter than a needle, say from a brass tube having an inside diameter of extrusion continuing slowly until the weight of the extruded grease exceeds its gel strength and a drop of grease breaks off.
  • a follower assembly for use in a tubular writing cartridge having a writing socket tip at one end thereof, an ink reservoir portion of small diameter in communi cation with said tip and an ink reservoir of large diameter in communication with said reservoir portion, and a body of ink in said reservoir and small reservoir portion, whereby virtually the entire body of ink may be utilized in writing, comprising:
  • a solid element centrally and movably positioned in said reservoir, said element having an outer diameter larger than said reservoir portion, said element having a through axial bore in alignment with the reservoir portion, the lower end of said element being in contact with the top surface portion of a body of ink in said reservoir;
  • bodies of viscous follower material within the axial 7 bore of said tubular element and between said element and walls of said reservoir, said bodies of viscous material being in contact with the top Surface of said body of ink;
  • tubular element being incapable of movement into the reservoir portion of small diameter while the body of viscous material within said tubular element is adapted to follow the ink into the reservoir portion.
  • a follower assembly as stated in claim 1 including a cylindrical solid element positioned within the body of viscous follower material within said tubular element, said cylindrical solid element being adapted to follow the ink into the reservoir portion and into proximity to the writing socket tip.
  • tubular element is provided with a lower conical surface adapted to contact the cartridge at a zone where the small diameter reservoir portion communicates with the ink reservoir.
  • tubular element is provided with a downwardly directed extension of smaller diameter than said reservoir portion and the axial bore extends through the element and its extension.

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  • Pens And Brushes (AREA)
  • Inks, Pencil-Leads, Or Crayons (AREA)
US498362A 1965-10-20 1965-10-20 Ink utilization in writing instruments Expired - Lifetime US3334616A (en)

Priority Applications (8)

Application Number Priority Date Filing Date Title
US498362A US3334616A (en) 1965-10-20 1965-10-20 Ink utilization in writing instruments
GB46384/66A GB1144788A (en) 1965-10-20 1966-10-17 Tubular writing cartridges
ES0332441A ES332441A1 (es) 1965-10-20 1966-10-19 Un dispositivo seguidor para la masa de tinta que comunica con la punta del receptaculo de escritura en un extremo de un cartucho de escritura tubular.
DE19661511380 DE1511380A1 (de) 1965-10-20 1966-10-20 Folgerbauteil fuer Tinte in einer Schreibpatrone
SE14329/66A SE320910B (pt) 1965-10-20 1966-10-20
AU13826/66A AU417459B2 (en) 1965-10-20 1966-11-11 Follower assembly for ink ina writing cartridge
CH1642266A CH453949A (de) 1965-10-20 1966-11-15 Schreibinstrument mit einem Tintenbehälter
BE692484D BE692484A (pt) 1965-10-20 1967-01-11

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
US498362A US3334616A (en) 1965-10-20 1965-10-20 Ink utilization in writing instruments
AU13826/66A AU417459B2 (en) 1965-10-20 1966-11-11 Follower assembly for ink ina writing cartridge

Publications (1)

Publication Number Publication Date
US3334616A true US3334616A (en) 1967-08-08

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Application Number Title Priority Date Filing Date
US498362A Expired - Lifetime US3334616A (en) 1965-10-20 1965-10-20 Ink utilization in writing instruments

Country Status (7)

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US (1) US3334616A (pt)
AU (1) AU417459B2 (pt)
BE (1) BE692484A (pt)
CH (1) CH453949A (pt)
DE (1) DE1511380A1 (pt)
GB (1) GB1144788A (pt)
SE (1) SE320910B (pt)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3495920A (en) * 1968-01-15 1970-02-17 Parker Pen Co Ball pen refill
US6132124A (en) * 1993-08-31 2000-10-17 Mitsubishi Pencil Kabushiki Kaisha Ink follower for aqueous ballpoint pen using gel-like material and solid piece
US6361234B1 (en) 2000-03-08 2002-03-26 Bic Corporation Pressurized writing instrument employing a compressible piston member
EP1234688A1 (en) * 2001-02-26 2002-08-28 Kotobuki & Co. Ltd. Ink reservoir for writing refill
US20100272494A1 (en) * 2009-04-24 2010-10-28 Kokai Kenji Stick-shaped material extruding container and cosmetics

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR971301A (fr) * 1948-08-13 1951-01-16 Nouveau stylo à bille
GB798897A (en) * 1955-12-22 1958-07-30 Ernest Verrinder Wagner Improvements in ball-tipped and like writing instruments
CA646258A (en) * 1962-08-07 Norman H. Gerlach Sealing means for the ink reservoirs of ball point writing implements
US3082740A (en) * 1961-07-10 1963-03-26 Northern Ind Products Company Writing instrument

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CA646258A (en) * 1962-08-07 Norman H. Gerlach Sealing means for the ink reservoirs of ball point writing implements
FR971301A (fr) * 1948-08-13 1951-01-16 Nouveau stylo à bille
GB798897A (en) * 1955-12-22 1958-07-30 Ernest Verrinder Wagner Improvements in ball-tipped and like writing instruments
US3082740A (en) * 1961-07-10 1963-03-26 Northern Ind Products Company Writing instrument

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3495920A (en) * 1968-01-15 1970-02-17 Parker Pen Co Ball pen refill
US6132124A (en) * 1993-08-31 2000-10-17 Mitsubishi Pencil Kabushiki Kaisha Ink follower for aqueous ballpoint pen using gel-like material and solid piece
US6361234B1 (en) 2000-03-08 2002-03-26 Bic Corporation Pressurized writing instrument employing a compressible piston member
EP1234688A1 (en) * 2001-02-26 2002-08-28 Kotobuki & Co. Ltd. Ink reservoir for writing refill
US20100272494A1 (en) * 2009-04-24 2010-10-28 Kokai Kenji Stick-shaped material extruding container and cosmetics
US7938591B2 (en) * 2009-04-24 2011-05-10 Tokiwa Corporation Stick-shaped material extruding container and cosmetics

Also Published As

Publication number Publication date
CH453949A (de) 1968-03-31
BE692484A (pt) 1967-07-11
GB1144788A (en) 1969-03-12
AU1382666A (en) 1968-05-16
SE320910B (pt) 1970-02-16
DE1511380A1 (de) 1970-03-12
AU417459B2 (en) 1971-09-24

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