Eraser Patents (Class 15/424)
-
Publication number: 20150033499Abstract: Provided are an erasing implement and a writing implement equipped with the erasing implement, the erasing implement being capable of erasing writing regardless of the type of ink or lead of the writing implement, even writing with thermochromic ink or writing with pencil lead. The erasing implement is equipped with a first erasing member for erasing writing with thermochromic ink and a second erasing member for erasing writing of types other than thermochromic ink, and is configured by covering the outer surface of the second erasing member with the first erasing member.Type: ApplicationFiled: January 24, 2013Publication date: February 5, 2015Applicant: MITSUBISHI PENCIL COMPANY, LIMITEDInventors: Sakae Hayao, Hiroshi Ohtsuka, Tsuyoshi Nishida
-
Publication number: 20140230847Abstract: A cleaning implement includes an erodible foam adapted to contact a surface to be cleaned and a hydrophobic film attached to the erodible foam. The erodible foam is adhered to the hydrophobic film with an adhesive attachment. The cleaning implement may also include a handle attached to the impermeable film.Type: ApplicationFiled: February 18, 2014Publication date: August 21, 2014Applicant: The Procter & Gamble CompanyInventor: David John PUNG
-
Patent number: 8783986Abstract: An eraser device for a writing implement includes an eraser body having eraser material on at least one end thereof, and an attachment loop having a loop end connecting a pair of spaced legs, respective leg ends of the spaced legs being attached to the eraser body, the attachment loop being dimensioned to accommodate a shaft of the writing implement therein between the spaced legs and the loop end. The eraser body can be a recycled pencil stub.Type: GrantFiled: November 7, 2013Date of Patent: July 22, 2014Inventor: Rosemary DeFrancisci
-
Publication number: 20140150203Abstract: Provided are an erasing member which is excellent in erasability for handwritings written by means of a pencil, a mechanical pencil and the like and which does not produce eraser dusts, and an erasing tool in which a part to be erased can be visually recognized in erasing. The erasing member comprises a blend composition containing a liquid-absorbing porous material, and a basic magnesium carbonate porous material and the like can be used as the liquid-absorbing porous material. And in an erasing tool in which an erasing part is formed at one end and in which a transparent or translucent visible part making it possible to visually recognize a writing surface is provided in the vicinity of the erasing part, the erasing member described above is mounted to the erasing part, whereby the erasing tool which does not produce eraser dusts is obtained.Type: ApplicationFiled: November 25, 2013Publication date: June 5, 2014Applicant: MITSUBISHI PENCIL COMPANY, LIMITEDInventors: Satoru Banzai, Toshimi Kamitani, Yosuke Setagawa, Hitoshi Kino, Tooru Nakajima
-
Publication number: 20140082885Abstract: The invention provides a plastic eraser comprising a vinyl chloride resin as a base resin and a combination of 4,5-epoxy-1,2-cyclohexanedicarboxylic acid bis(2-ethylhexyl) and diethylene glycol dibenzoate as plasticizers, wherein the plastic eraser comprises the base resin in an amount of 25-60% by weight, and the combination of plasticizers in an amount of 30-60% by weight, and wherein the proportion of the diethylene glycol dibenzoate in the combination of plasticizers is 5-60% by weight, and wherein the plastic eraser has a hardness in the range of 55-75, and a gel hardness in the range of 3.0-6.0 kgf.Type: ApplicationFiled: March 23, 2012Publication date: March 27, 2014Applicant: SAKURA COLOR PRODUCTS CORPORATIONInventor: Shinji Tsujio
-
Patent number: 8214969Abstract: A layered eraser, comprising: a plurality of eraser layers, comprising at least an innermost eraser layer and an outermost eraser layer; the outermost eraser layer containing the innermost eraser layer; each eraser layer adjacent at least one other eraser layer; each of the eraser layers having an outermost surface. The layered eraser may be adapted to fit about a writing instrument. Each eraser layer adjacent another eraser layer may have different shaped outermost surfaces. Embodiments include different eraser layers in the shapes of simulated space ships, simulated dinosaur heads, and simulated planets. In a preferred embodiment, the plurality of eraser layers comprise an innermost eraser layer, at least one intermediate eraser layer completely surrounding the innermost eraser layer, and an outermost eraser layer completely surrounding the at least one intermediate layer, one or more eraser layers being exposed after at least a portion of the layered eraser is worn away.Type: GrantFiled: August 4, 2008Date of Patent: July 10, 2012Inventor: Gavin Curtis
-
Patent number: 8173052Abstract: A writing implement with a thermochromic coloring color-memory composition which comprises a homogeneous solubilized mixture of (A) an electron donative coloring organic compound, (B) an electron accepting compound and (C) a reaction medium which controls color reactions of the components (A) and (B), wherein a complete decoloring temperature (T4) of the thermochromic coloring color-memory composition is 50° C. or higher and a coloring starting temperature (T2) of thermochromic coloring color-memory composition is 10° C. or lower regarding the color density-temperature curve, and the thermochromic coloring color-memory composition has color-memory ability at the ordinary temperature range.Type: GrantFiled: July 29, 2010Date of Patent: May 8, 2012Assignee: The Pilot Ink Co., Ltd.Inventor: Katsuyuki Fujita
-
Publication number: 20110247171Abstract: An eraser comprised of a band of vulcanized silicone rubber, to be worn on a human wrist, capable of erasing marks, such as pencil and pen markings from a surface.Type: ApplicationFiled: April 8, 2010Publication date: October 13, 2011Applicant: THE ERASELET COMPANY LLCInventor: Bryan Ricci
-
Publication number: 20100313381Abstract: An eraser includes a housing (20) having a receiving chamber (21), a collection zone (23) and a plurality of reinforcing ribs (26), a mounting board (30) mounted on the housing, a cleaning member (40) mounted on the mounting board, a support bracket (50) mounted on the housing, a door (60) removably mounted on the housing to cover the collection zone, a hollow separation member (70) mounted in the housing to separate the receiving chamber from the collection zone, and a control valve (80) movable to open the separation member so as to connect the receiving chamber with the collection zone or to close the separation member so as to interrupt a connection between the receiving chamber and the collection zone, and two decorative covers mounted on the housing and each abutting the reinforcing ribs.Type: ApplicationFiled: June 15, 2009Publication date: December 16, 2010Inventor: Ming-Feng Yu
-
Publication number: 20100146731Abstract: An eraser to cap a pencil includes a top and a base, with a projection extending between them. The projection helps to secure the top and base together by fitting into and filling a mating cavity within either or both of the top and base. The base has a cavity open at the bottom of the base, sized and shaped to receive the used or unused portion of an original pencil eraser, if any, and the ferrule on the pencil.Type: ApplicationFiled: December 15, 2008Publication date: June 17, 2010Inventor: Andrew Curren
-
Patent number: 7732523Abstract: An elastomer composition is provided which contains a matrix of poly-(3-hydroxybutyrate-co-3-hydroxyhexanoate) produced from microorganisms and crosslinked natural rubber particles dispersed like islands in the matrix. An eraser using the elastomer composition is also provided. The present invention is capable of providing an elastomer composition and eraser using the same, which can be recycled, are friendly to the environment, and corresponds to the recycling society, without relying on fossil resources.Type: GrantFiled: January 8, 2008Date of Patent: June 8, 2010Assignee: Seed Company Ltd.Inventors: Kazuki Morimoto, Yasuhiro Nishioka
-
Patent number: 7732524Abstract: An elastomer composition is provided which contains a matrix of biomass plastic and crosslinked natural rubber particles dispersed like islands in the matrix. An eraser using the elastomer composition is also provided. The present invention is capable of providing an elastomer composition and eraser using the same, which can be recycled, are friendly to the environment, and corresponds to the recycling society, without relying on fossil resources.Type: GrantFiled: July 24, 2008Date of Patent: June 8, 2010Assignee: Seed Company Ltd.Inventors: Kazuki Morimoto, Yasuhiro Nishioka
-
Publication number: 20090083916Abstract: A two piece eraser assembly for use as a rotary tool attachment for abrading surfaces enables quick and easy replacement of worn eraser disks without requiring the assistance of any hand held tools in either the removal or in the reinstallation process. The assembly, including aftermarket replacement parts therefor, comprise an eraser disk and an eraser hub for mounting and holding the eraser disk. The eraser hub includes upper and lower surfaces, wherein the eraser hub upper surface features a centrally positioned throughbore, a flange at the peripheral edge of the hub and a stub shaft on the lower surface positioned axially with the throughbore. The eraser hub includes a plurality of spaced apertures for engaging with and detachably locking eraser disk extensions on the backside, so the eraser disk is mounted flush with the eraser hub. The upper surface of the eraser disk includes a central recess and an aperture in the recess keyed for axially alignment with the throughbore of the eraser hub.Type: ApplicationFiled: October 2, 2007Publication date: April 2, 2009Applicant: Dynabrade, Inc.Inventors: Mark Lampka, Matthew A. Giles
-
Publication number: 20090031527Abstract: A layered eraser, comprising: a plurality of eraser layers, comprising at least an innermost eraser layer and an outermost eraser layer; the outermost eraser layer containing the innermost eraser layer; each eraser layer adjacent at least one other eraser layer; each of the eraser layers having an outermost surface. The layered eraser may be adapted to fit about a writing instrument. Each eraser layer adjacent another eraser layer may have different shaped outermost surfaces. Embodiments include different eraser layers in the shapes of simulated space ships, simulated dinosaur heads, and simulated planets. In a preferred embodiment, the plurality of eraser layers comprise an innermost eraser layer, at least one intermediate eraser layer completely surrounding the innermost eraser layer, and an outermost eraser layer completely surrounding the at least one intermediate layer, one or more eraser layers being exposed after at least a portion of the layered eraser is worn away.Type: ApplicationFiled: August 4, 2008Publication date: February 5, 2009Inventor: Gavin Curtis
-
Publication number: 20080172828Abstract: A method of cleaning a carpet stain comprising: optionally treating the carpet stain with a carpet cleaner, rubbing the carpet stain optionally treated with the carpet cleaner with a cleaning implement, and optionally removing a residual from the carpet.Type: ApplicationFiled: January 22, 2008Publication date: July 24, 2008Inventor: Jeffrey Lee Butterbaugh
-
Patent number: 7350995Abstract: A marker eraser system for efficiently combining an eraser with a dry erase marker. The marker eraser system includes a body having a tubular structure and a central aperture extending through the tubular structure. The central aperture extends through an inner end to an outer end of the body. An eraser member is attached to the outer end of the eraser unit to erase a removable ink from a dry erase marker. An outer end of the central aperture frictionally receives an outer portion of a first end of a cap of the dry erase marker to allow a user to removably attach the marker eraser system to the cap of the dry erase marker.Type: GrantFiled: December 19, 2006Date of Patent: April 1, 2008Inventor: Julia M. Rhodes
-
Patent number: 7341635Abstract: An eraser is constituted by an elastic material containing a rubber component or a resin component, and a skeleton structure for reinforcing the elastic material, and the skeleton structure is made from a porous structural material such as from an organic polymer that is broken when rubbed. Void portions in the porous structural material of the skeleton structure contain the elastic material of the eraser composition. Here, the skeleton portions of the skeleton structure may have an average thickness of 1 to 100 ?m, and the void portions may have an average pore size of 10 ?m to 3 mm. The eraser may have a surface hardness of 50 to 80, and also a sticking strength of 1.5 to 20 (kgf).Type: GrantFiled: November 22, 2006Date of Patent: March 11, 2008Assignee: Sakura Color Products CorporationInventors: Shinichiro Hayashi, Ryuzo Yamamoto
-
Patent number: 7316841Abstract: An eraser is constituted by an elastic material containing a rubber component or a resin component, and a skeleton structure for reinforcing the elastic material, and the skeleton structure is made from a porous structural material such as from an organic polymer that is broken when rubbed. Void portions in the porous structural material of the skeleton structure contain the elastic material of the eraser composition. Here, the skeleton portions of the skeleton structure may have an average thickness of 1 to 100 ?m, and the void portions may have an average pore size of 10 ?m to 3 mm. The eraser may have a surface hardness of 50 to 80, and also a sticking strength of 1.5 to 20 (kgf).Type: GrantFiled: August 24, 2000Date of Patent: January 8, 2008Assignee: Sakura Color Products CorporationInventors: Shinichiro Hayashi, Ryuzo Yamamoto
-
Patent number: 6732407Abstract: A writing implement having a forward-positioned eraser, and method. The eraser circumscribes the shaft of the writing implement, and may have an annular or doughnut shape. The eraser may be affixed to the shaft portion, for example where used with a fixed-length writing implement such as a mechanical pencil or erasable pen. The eraser may, alternatively, be slidable along the shaft portion, which would make the eraser useable with a sharpenable pencil, the length of which will be changed as a result of sharpening.Type: GrantFiled: April 26, 2002Date of Patent: May 11, 2004Inventor: Daniel Kamrath Weiss
-
Patent number: 6505984Abstract: The crayon assembly includes a crayon and an eraser. The crayon is made of a material which can make a mark on paper and which is capable of being erased from paper. The crayon assembly may also include a label. The crayon may include an attachment portion which may be a pocket. The eraser may include an attachment portion which may be a post. The post corresponds to the pocket. The attachment portions may have different shapes and/or cross sections. The crayon may be connected to the eraser by molding. In other embodiments the eraser may be connected to the crayon by an adhesive, by a ferrule or by other configurations.Type: GrantFiled: April 27, 2001Date of Patent: January 14, 2003Assignee: Binney & Smith Inc.Inventors: David S. Smith, Douglas A. Brand, Vito Niosi, Robert S. Volk
-
Patent number: 6441091Abstract: An eraser composition comprising 22-41 wt % styrene-ethylene/butylene-styrene block copolymer, 5-15 wt % ethylene/propylene copolymer, 30-50 wt % calcium carbonate, 10-25 wt % factice; and 0.1-7 wt % pumice is provided. The eraser composition optionally contains up to 1 wt % titanium dioxide. The eraser composition preferably has a hardness of from 70 to 85 Shore A.Type: GrantFiled: July 27, 2001Date of Patent: August 27, 2002Assignee: Binney & SmithInventors: Jacob Leidner, David G. Cook, Luis Rodrigo Pineiro
-
Patent number: 6416241Abstract: A pencil (20) includes a threaded end (30). A threaded ferrule (24) surrounds an eraser (26), and threadably engages the threaded end (30). When the ferrule (24) is rotated, it screws down on the threaded end (30) thereby exposing an unused portion of the eraser (26). A stop mechanism (34) prevents the ferrule (24) from being unscrewed from the threaded end (30).Type: GrantFiled: July 17, 2001Date of Patent: July 9, 2002Inventor: Gordon Adams
-
Patent number: 6083345Abstract: A tool for removing adhesive residues, films or the like from a metal surface contains a shank, which can be rotated by a drive mechanism. A disk made from rubber or a plastics material is clamped in non-rotary manner to the shank.Type: GrantFiled: August 12, 1998Date of Patent: July 4, 2000Assignee: Adolf Wurth GmbH & Co. KGInventor: Uwe Frank
-
Patent number: 6007891Abstract: An eraser for a dry surface erase is disclosed. The eraser includes a cylinder having a tangentially extending flat surface to thereby form a "b" shaped member. The cylinder is provided with a covering of felt, cloth or other substance suitable for erasing material written on a dry-erase board. The felt covering extends over approximately one-third of the external surface of the cylinder. Alternatively, as shown in FIG. 6B, an eraser may be comprise a half-cylinder having a tangentially extending flat surface. A cylindrical insert is inserted into the half-cylinder and is retained by friction fit or by an adhesive. The cylindrical. Insert preferably comprises a foam material suitable for erasing dry erase surfaces.Type: GrantFiled: June 17, 1997Date of Patent: December 28, 1999Assignee: Boone International, Inc.Inventors: Bradley C. Davis, Michael K. Boone
-
Patent number: 5957603Abstract: A support for a dry erase marker and eraser for wiping writing medium of such a marker from a writing surface includes a stopper having a load bearing end face opposite from a connector surface. The connector surface is engagable with an end of the dry erase marker which is opposite a dispenser for the wipeable marker medium. A layer of pile material is supported by the load bearing end face for wiping writing medium from the writing surface while retained and supported by the housing from a ledge forming a generally horizontal support surface protruding from a writing surface. A layer of hook material is adhered to the horizontal ledge. The layers of hook and pile material are sufficiently interconnected upon contact there between to support the dry erase marker from the ledge so that the influence of gravity acting on a dry erase marker maintains the dispenser wet with writing medium.Type: GrantFiled: November 18, 1997Date of Patent: September 28, 1999Inventor: Charles E. Bell
-
Patent number: 5855442Abstract: A whiteboard marking pen includes an ink-containing pen casing having an ink applicator extending from a first end of the casing and a plug socket in a second end of the pen casing; a cylindrical pen cap including a socket end surrounding the ink applicator in a capped storage state and a plug first end insertible into the pen casing plug socket in a pen uncapped marking state; and a whiteboard eraser juxtaposed to a cylindrical portion of the pen cap and extending cantilevered outwardly with respect to a distal surface of the cap socket end, such that, when the pen cap is plugged into the pen casing plug socket, a peripheral edge of the cantilevered eraser is positioned for erasing a minor area of an ink image on a whiteboard.Type: GrantFiled: November 15, 1996Date of Patent: January 5, 1999Inventor: Scott A. Keller
-
Patent number: 5709491Abstract: A tubular eraser for erasing ink or pencil marks comprises an elongated body of a rubber material. The elongated body has an insertion hole of a predetermined length and extending along the direction of the axis of the elongated body for accommodating an ink reservoir of a ball-point pen.Type: GrantFiled: January 3, 1996Date of Patent: January 20, 1998Inventor: Thomas Yeh
-
Patent number: 5584592Abstract: A combination ballpoint pen and mechanical pencil comprising a barrel with a nose cone having a hole therethrough. A plurality of different writing cartridges are provided, with each writing cartridge having a writing tip. A component is for radially positioning the writing cartridges within the barrel, so that the writing tips will face the hole in the nose cone of the barrel. Structures are for facilitating manual movement of each writing cartridge with the writing tip to and from the nose cone of the barrel. An element is for guiding one writing tip of one writing cartridge into and out of the hole in the nose cone of the barrel. When the writing tip extends out of the hole, a person can grip the barrel and write with the writing tip.Type: GrantFiled: May 15, 1995Date of Patent: December 17, 1996Inventor: Elizabeth Craig
-
Patent number: 5530984Abstract: An eraser is disclosed. The eraser includes a frame formed of tubular components coupled together. The frame includes a first peripheral member having long parallel side edges, a short rear edge and a triangular shaped front edge. The side edges are about twice the length of the rear edge. Three cross-brace members including a front cross-brace member constitute the base of the triangle. Additional cross-brace members are at equally spaced locations on the interior faces of the side edges. A handle is formed of a rod extending upwardly from the central extent of the forward cross brace. The handle extends rearwardly at a right angle to and over the central cross brace member with a plastic grip member of an enlarged diameter with finger receiving recesses on its lower extent secured to the end of the handle remote from the frame. A flexible cover is secured over the lower surface of the frame and is essentially co-extensive therewith.Type: GrantFiled: August 31, 1995Date of Patent: July 2, 1996Inventor: William E. Walker
-
Patent number: 5388306Abstract: An eraser for a ring binder comprising an eraser element having at least one hole extending therethrough. The hole is sized so as to provide access to a ring of a ring binder. The eraser preferably has a triangle-like shape comprising a base, a first side, and a second side. The base is preferably curved so as to accommodate a notebook organizer of the type having an organizer base with a substantially flat bottom surface and with a plurality of holes being adapted for engagement with the rings of a ring notebook.Type: GrantFiled: August 25, 1993Date of Patent: February 14, 1995Inventor: Mark A. Bedol
-
Patent number: 5345652Abstract: A refill eraser comprises at least one refill member. Each refill member includes a holding barrel having a partition portion and a plurality of rotation-preventive ridges formed on an inner peripheral surface of its front portion, and an eraser body having a generally frustro-conical front end portion, a cylindrical intermediate portion, and a cylindrical rear end portion. The eraser body is press-fitted into and held at its rear end portion and intermediate portion within the front portion of the holding barrel with its rear end portion and intermediate portion engaged with the ridges and with its rear end supported by the partition portion. The front end portion of the eraser body protrudes from the front end of the holding barrel. A plurality of the refill members are refillably held within an elongated tubular shaft. A front end of the eraser body located on the foremost end protrudes from a front end of the tubular shaft.Type: GrantFiled: January 14, 1994Date of Patent: September 13, 1994Assignee: Pioneer Industrial Co.Inventor: Cheng-Hwa Chuang
-
Patent number: 4979254Abstract: An eraser mover for use with a power eraser comprising mechanical means for sliding the eraser out of its holder by inserting prongs into the eraser and moving the prongs outwardly.Type: GrantFiled: March 12, 1990Date of Patent: December 25, 1990Inventor: Gordon L. Naujock
-
Patent number: 4872777Abstract: Means and method for eradicating (i.e. removing) images affixed to copies of drawings or other documents made on electrostatic media by electrostatic copiers.Type: GrantFiled: December 3, 1987Date of Patent: October 10, 1989Assignee: Teledyne Industries, Inc.Inventor: Gary R. Dalbke
-
Patent number: 4796328Abstract: An eraser capable of erasing characters and the like written on paper with a ball-point pen, fountain pen, typewriter, word processor, color pencil or the like. The eraser has an integral structure composed of plural types of eraser pieces having different hardnesses and an abrasive material, the eraser pieces and the abrasive material existing respectively in a particulately dispersed state. A method for manufacturing such eraser comprises steps of kneading plural types of major eraser materials which have been previously vulcanized and shaped at need with an abrasive material and vulcanizing and shaping the resulting mixture. These plural types of major eraser materials are such that erasers having different hardnesses can be produced if each of the major eraser materials is either vulcanized or heated and shaped alone and that particles of the major eraser materials exist independently from one another even if these materials are kneaded.Type: GrantFiled: December 16, 1987Date of Patent: January 10, 1989Assignee: Horie Sangyo Kabushiki KaishaInventor: Fumio Horie
-
Patent number: 4554703Abstract: A device for use with an eraser of a rubber composition having magnetic particles dispersed therein. The device has a permanent magnet for attracting the magnetic dust created by use of the eraser. For the ready removal of the collected dust the device further comprises a shield normally enclosing the magnet. When held close to or in direct contact with a dust collecting wall forming a part of the shield, the magnet attracts eraser dust therethrough. The eraser dust attached to the dust collecting wall can be readily released, as into a suitable receptacle such as a trash can, as the magnet is moved away from the dust collecting wall as by being pulled out of the shield. The device may incorporate a magnetic eraser to provide a convenient eraser/dust collector combination, as in some embodiments disclosed herein. Additional embodiments suggest the combined use of a brush for collecting eraser dust, and the provision of an open space for confining the collected dust on the dust collecting wall of the shield.Type: GrantFiled: January 19, 1984Date of Patent: November 26, 1985Assignee: Taiyo Yuden Co., Ltd.Inventor: Shouzo Matuki
-
Patent number: 4485520Abstract: Uniformly porous foamed erasers and process for the production thereof, the process comprising continuously mixing air or other gas into a flowable plasticized mixture and gelling the mixture by introducing the same continuously to a heating mean.Type: GrantFiled: November 3, 1980Date of Patent: December 4, 1984Assignee: Firma J. S. StaedtlerInventors: Werner Handl, Rupert Englbrecht
-
Patent number: 4374225Abstract: A method of fabricating an eraser which contains a main basic material of low crystallizable polyolefin thermoplastic elastomer and normal synthetic rubbers having no hard segment for performing a crosslinking effect, namely, any one or more of chlorinated polyethylene, ethylene-propylene terpolymer, ethylene ethyl acrylate, ethylene-vinyl acetate copolymer, atactic polypropylene, styrene-butadiene rubber, nitrile rubber and the like. The thermoplastic elastomer exhibits similar properties to vulcanized rubber without particular vulcanizing operation and crosslinking reaction. In case that less than 40 parts by weight of the elastomer is contained in the eraser, the composition does not form an eraser, while in case that higher than 100 parts by weight of the elastomer is contained in the eraser, the composition incorporates excessive rubber-like properties.Type: GrantFiled: October 10, 1980Date of Patent: February 15, 1983Assignee: Mitsubishi Pencil Co., Ltd.Inventors: Takamasa Kawakubo, Kiyosi Hirasawa
-
Patent number: 4268411Abstract: A process for preparing microcapsules comprising a core of highly viscous liquid substance encapsuled with a wall of an aggregate of finely divided silica powder, which comprises adding the highly viscous liquid substance into a powder bed of the finely divided silica powder under stirring with a cutter. The microcapsules thus obtained have such a structure that the core of highly viscous liquid substance is coated with a wall of an aggregate of the finely divided silica powder and a gelatinized layer formed between the wall and the liquid core substance.Type: GrantFiled: March 29, 1979Date of Patent: May 19, 1981Assignee: Pentel Kabushiki KaishaInventors: Masahiro Iwata, Yuichi Taka