US3455276A - Magnetically responsive powder applicator - Google Patents

Magnetically responsive powder applicator Download PDF

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Publication number
US3455276A
US3455276A US640720A US3455276DA US3455276A US 3455276 A US3455276 A US 3455276A US 640720 A US640720 A US 640720A US 3455276D A US3455276D A US 3455276DA US 3455276 A US3455276 A US 3455276A
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US
United States
Prior art keywords
sleeve
magnetic
members
shaft
powder
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
US640720A
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English (en)
Inventor
Glenn R Anderson
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.)
3M Co
Original Assignee
Minnesota Mining and Manufacturing Co
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Filing date
Publication date
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Publication of US3455276A publication Critical patent/US3455276A/en
Anticipated expiration legal-status Critical
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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G9/00—Developers
    • G03G9/08—Developers with toner particles
    • G03G9/083—Magnetic toner particles
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G15/00—Apparatus for electrographic processes using a charge pattern
    • G03G15/06—Apparatus for electrographic processes using a charge pattern for developing
    • G03G15/08—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer
    • G03G15/09—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer using magnetic brush
    • G03G15/0921—Details concerning the magnetic brush roller structure, e.g. magnet configuration

Definitions

  • An applicator for magnetically responsive, finely divided particulate material comprising a magnetizable shaft, a number of elongate magnetic members disposed in an annular array about and extending along said shaft in close fitting relation with the radially inner and outer surfaces of adjacent members having opposite polarity, a non-magnetic sleeve disposed about the periphery of said array, and means affording relative rotation between said sleeve and said members.
  • This invention relates to an applicator for use in presenting magnetically responsive, finely divided particles against the surface of an article for application thereto.
  • the present invention is particularly useful in applying pigmented particulate material to an article to develop an image thereon.
  • One example of such use is in develop ing imagewise a differentially conductive pattern formed by projecting a light image on a photoconductive web.
  • the photoconductive web being positioned between an insulative layer, backed by an electrode, and a second electrode contacting the particulate or powder which is in electrically conductive contact between the second electrode and the photoconductive web.
  • the device described in the second patent, No. 3,176,- 652, particularly with reference to FIGURE 3 thereof, employs a fixed magnetic member which can be generally cylindrical in shape but which is formed with axially extending alternating flutes and ribs with each rib constituting a magnetic pole of a polarity opposite to that of the next adjacent rib.
  • This spacing between poles of op- 3,455,276 Patented July 15, 1969 posite polarity while providing a magnetic field which varies direction around the periphery, produces areas be tween the ribs having a reduced field. Consequently the amount of magnetic material held on the sleeve and the powder movement are decreased because the field varies with weak tangential magnetic field being present opposite the flutes.
  • the device of the present invention affords an applicator having a uniform field along its length and strong fields around its circumference.
  • the present invention provides an applicator for applying to a wide surface a dimensionally uniform deposition of magnetically responsive particulate material.
  • a plurality of magnetic members which are formed preferably of oriented anisotropic permanent magnet material dispersed in a nonmagnetic immobilizing matrix, are disposed in a circular array about a core formed of a high magnetic permeability and low loss such as soft iron and a relatively rotatable non-magnetic sleeve which supports the particulate image-forming material to be moved from a hopper to engaging relation with an image carrying surface.
  • FIGURE 1 is a vertical sectional view of an applicating roller formed in accordance with the present invention.
  • FIGURE 2 is a diagrammatic view showing the roller of the present invention in cross-section and its relation to other elements in a coating assembly;
  • FIGURE 3 is a perspective view illustrating one magnetic member
  • FIGURE 4 is a graph showing the magnitude of the radial and tangential components of the circumferential magnetic field.
  • FIGURE 5 is a netic field.
  • FIG- URES 1 and 2 a developing assembly comprising an applying roll assembly 10 adjustably supported between suitable insulated side frame members 11 and 12.
  • the assembly 10 comprises a core or shaft 13 formed of a material having a high magnetic permeability and low loss, e.g. soft iron, supported at opposite ends in the frame members.
  • a core or shaft 13 formed of a material having a high magnetic permeability and low loss, e.g. soft iron, supported at opposite ends in the frame members.
  • the members 14 graph showing the longitudinal magand 15 are positioned between a fixed washer 16 and a clamping washer 17.
  • Rotatably mounted relative to the shaft 13, as by bearing mounted end caps 18 and 19, is a non-magnetic cylindrical sleeve 20 formed of a material which will not shield the magnetic field from members 14 and 15.
  • sleeve 20 On each end of sleeve 20 is a drive ring 21 against which and in driving contact therewith are drive discs 22 supported by a driven shaft 23.
  • Shaft 23 is journalled and adjustably mounted in the frame members 11 and 12 and has a drive pulley 24 on one extended end thereof which may be suitably driven from a belt 25 from a motor (not shown).
  • the applicating roll should serve as an electrode; therefore it is desired to connect the sleeve 20 to a source of electrical potential; and in the illustrated embodiment a connector 26 is attached to the shaft 13, to which a lead from a source of potential may be coupled.
  • the sleeve 20 is electrically connected to the shaft 13 by a sliding leaf 27 of U-shaped resilient conductive material.
  • the sleeve in this example is preferably formed of aluminum but could be formed of another non-magnetic material such as glass with an electrically conductive, non-magnetic surface coating.
  • the roll assembly 10 in operation, is positioned above a tray 30, mounted between the side frame members 11 and 12 and positioned for parallel aligned spaced relation to a rotating drum surface as illustrated at 31 or to a linear or convexly supported moving belt or web.
  • a relatively moving surface 31 carries an undeveloped image pattern to which is to be applied an even coating of particulate image-forming magnetically responsive material hereinafter referred to'as powder 33, which may be supplied to the roll assembly from a supply disposed in the hopper-like tray 30.
  • the tray 30 has an adjustable doctor blade 34 mounted along a forward upturned lip which permits spatial adjustment relative to the outer surface of sleeve 20.
  • the doctor blade 34 may be adjusted between 0.010 inch and 0.05 inch.
  • the position of the sleeve 20 is also adjustable toward and away from the surface 31 to afford light contact between the powder 33 and the surface 31 or some compressive pressure on the powder at the interface between the sleeve and the surface.
  • the magnetic members 14 and 15 are alternately magnetically polarized elongate members which are generally shaped as sectors of a ring or sectors of a hollow cylinder having radially inner faces 35 concavely curved and convex radially outer surfaces 36 joined by radially extending edge walls 37.
  • the shape of the members result in some vagaries in the dimensions and, although the members generally contact each other, a slight gap may exist in the array between one or more members and not disturb the performance.
  • the members 15 are polarized to have a different magnetic pole on the outer surface than on the inner face; for example, the north pole indicated at N is on the outer surface 36, and the south pole indicated at S is along the inner face 35, The members 14 would be oppositely polarized with N on the inner face and S along the outer surface.
  • the members 14 and 15 are formed by extrusion of a non-magnetic matrix which may be a resinous or plastic composition, an elastomeric semi-solid, or viscous liquid, capable of hardening, setting or being cured to a solid state in which is evenly dispersed anisotropic ferrite domain-sized particles, which particles are capable of achieving physical orientation when acted upon by internal shear stresses.
  • a non-magnetic matrix which may be a resinous or plastic composition, an elastomeric semi-solid, or viscous liquid, capable of hardening, setting or being cured to a solid state in which is evenly dispersed anisotropic ferrite domain-sized particles, which particles are capable of achieving physical orientation when acted upon by internal shear stresses.
  • the particles are certain fine grain permanent magnet materials particularly the ferrites of barium, lead and strontium which are easily magnetized to saturation.
  • the matrix may be natural rubber with compound agents, plasticizers, vulcanizing agents, and the like to provide the hardness
  • the members 14 and 15 provide, with a 1 to 1 ratio between the radial dimension and the circumferential dimension, a surprisingly high flux density and, in the preferred annular array, provide a circumferential field with strong radial and tangential components.
  • FIGURE 4 the fiux density about the array of magnetic members 14 and 15 is plotted in gauss with the radial field component plotted in solid lines and the tangential field component plotted in dotted lines.
  • the maximum radial field exists along a radial line bisecting the magnetic members, and the plot illustrates a flux density at the poles of 500 gauss.
  • An optimum design is between 500 and 750 gauss at the poles.
  • the tangential flux density peaks between the magnetic members and is illustrated on the plot at 300 gauss.
  • FIGURE 5 shows a graph along the length of the magnetic members and illustrates the readings above one pole as it is scanned from end to end. This graph'illustrates the uniformity of the magnetic fi'eld along the entire length of the magnetic members and that the field falls only at the ends. This uniformity of field affords a very uniform powder application by a roll assembly constructed in accordance with this invention.
  • rotation of the sleeve 20 which sleeve has a smooth outer surface with a diameter of approximately 1.250 inches and inside diameter of 1.180 inches, with a minimum clearance about the surface of the magnetic members of about .005 inch, carries the developing powder 33 from the tray 30 across the doctor blade 34.
  • the powder particles appear to tumble under the effects of the changing directions of the magnetic field and move in the direction of rotation of the sleeve 20.
  • the powder appears as a dark stripe on the areas of the sleeve above the poles and gray above the joint between the magnetic members.
  • the gray stripe is reduced to a line.
  • the tumbling powder stands on the sleeve surface as tree rows and, when carried by clockwise rotation of sleeve 20 toward the clockwise rotating or oppositely moving surface 31, they will contact the surface to be deposited in the desired manner.
  • the spacing between sleeve 20 and surface 31 relative to the spacing between doctor blade 34 and the sleeve will determine the amount of powder per unit area placed in contact with the surface 31.
  • the uniform axial field along the sleeve provides for uniform coverage across the surface 31 to be coated. In most applications the surface to be coated has a width of from 8 /2 to 14 inches, or the width or length of copy sheets.
  • An applicating roller for placing a uniform layer of magnetically responsive dry particulate material in contact with a surface moved past the peripheral surface of said roller, said applicating roller comprising a shaft of high magnetic permeability material, a plurality of elongate, generally sector-shaped in cross section magnetic members formed of fine grain permanent magnet material dispersed in a non-magnetic immobilizing matrix, which members are positioned With the edges thereof generally radial and in side-by-side relation to define a circular array around said shaft, and the radially inner and radially outer faces of each member being arcuate with said radially inner and radially outer faces of adjacent members in said array being oppositely polarized, a uniform non-magnetic hollow cylindrical sleeve positioned over said array of magnetic members and extending axially relative .to said shaft, and means for mounting said sleeve and said shaft for relative rotation to carry a quantity of said particulate material on the outer surface of said sleeve;
  • each of said magnetic members has an axial length of between 8 and 14".
  • a powder applicator comprising in combination:
  • an applicating roller for applying magnetically responsive dry pigmented material onto a surface moved past the periphery of said roller, said applicating roller comprising a shaft formed of high magnetic permeability and low loss material; a plurality of elongate generally truncated sector-shaped magnetic members formed of ferrite permanent mag" net substantially domain sized particles oriented in a non-magnetic matrix, which members are arranged in side-by-side contacting relation and form a circular array about said shaft with radially outer surfaces of adjacent magnetic members having opposite polarity; a thin-Walled hollow cylindrical sleeve formed of non-magnetizable material positioned about and approximate to said array of magnetic members; and means for mounting said sleeve and said shaft for relative rotation, each of said magnetic members extending along a substantial portion of said shaft and covered by said cylinder;
  • a powder applicator as claimed in claim 7 wherein said shaft and magnet members are fixed and said sleeve is rotated about said shaft.
  • An applicator for developing an image on a surface with a pigmented finely divided dry magnetically responsive developer material comprising in combination,
  • a tray adapted to receive sai-d developer material
  • an applicating roller positioned relative to said tray for moving said developer material out of said tray, said applicating roller comprising a shaft of high magnetic permeability material,
  • a plurality of elongate, generally sector-shaped in cross section, magnetic members which are formed of oriented fine grain permanent magnet material dispersed in a non-magnetic immobilizing matrix and which have longitudinal edges which are generally radial and positioned with said edges in side-by-side contacting relation to form an arcuate array on the outer circular periphery of said shaft, said members also having arcuate radially inner and radially outer faces with said radially inner and radially outer faces of adjacent members in said array being oppositely polarized, and

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Magnetic Brush Developing In Electrophotography (AREA)
  • Rolls And Other Rotary Bodies (AREA)
US640720A 1967-05-23 1967-05-23 Magnetically responsive powder applicator Expired - Lifetime US3455276A (en)

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Application Number Priority Date Filing Date Title
US64072067A 1967-05-23 1967-05-23

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US (1) US3455276A (enrdf_load_html_response)
DE (1) DE1752408A1 (enrdf_load_html_response)
FR (1) FR1566007A (enrdf_load_html_response)
GB (1) GB1216915A (enrdf_load_html_response)
SE (1) SE335476B (enrdf_load_html_response)

Cited By (44)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3584601A (en) * 1968-10-28 1971-06-15 Xerox Corp Magnetic brush belt development
US3641980A (en) * 1969-10-20 1972-02-15 Xerox Corp Development apparatus
US3643629A (en) * 1969-10-20 1972-02-22 Minnesota Mining & Mfg Magnetic powder applicator
DE2224624A1 (de) * 1971-05-21 1972-11-30 Hitachi Metals Ltd Entwicklungsvorrichtung für eine elektrostatische Aufzeichnung
JPS496932A (enrdf_load_html_response) * 1972-01-26 1974-01-22
US3823688A (en) * 1972-01-26 1974-07-16 Xerox Corp Magnetic brush assembly
US3828730A (en) * 1971-05-21 1974-08-13 Hitachi Metals Ltd Electrostatic record developing apparatus
US3863603A (en) * 1974-01-07 1975-02-04 Ibm Magnetic brush roll having resilient polymeric surface
US3882821A (en) * 1969-03-08 1975-05-13 Canon Kk Developing device for electrophotography
US3892908A (en) * 1973-06-25 1975-07-01 Minnesota Mining & Mfg Coating of solid substrates with magnetically propelled particles
US3911865A (en) * 1973-03-30 1975-10-14 Xerox Corp Toner pickoff apparatus
DE2523811A1 (de) * 1974-05-28 1975-12-18 Minnesota Mining & Mfg Verfahren und einrichtung zum auftragen eines farbpulvers auf ein elektrographisches aufzeichungsmittel
JPS518745U (enrdf_load_html_response) * 1974-07-05 1976-01-22
US3937181A (en) * 1973-05-23 1976-02-10 Fuji Xerox Co., Ltd. Magnetic brush type developing mechanism in electrophotographic copying machine
JPS5143147A (enrdf_load_html_response) * 1974-10-11 1976-04-13 Hitachi Metals Ltd
US3950089A (en) * 1975-02-24 1976-04-13 Xerox Corporation Coated roll for magnetic brush development and cleaning systems
US3952701A (en) * 1974-11-05 1976-04-27 Hitachi Metals, Ltd. Electrostatic developing apparatus
US3968773A (en) * 1972-05-22 1976-07-13 Xerox Corporation Magnetic brush developing apparatus
US3981271A (en) * 1974-02-20 1976-09-21 Fuji Xerox Co., Ltd. Magnetic brush type developer for use in an electrophotographic machine
US4040387A (en) * 1972-09-24 1977-08-09 Mita Industrial Co. Ltd. Electrostatic photographic copying apparatus
US4068622A (en) * 1975-10-22 1978-01-17 Oce-Van Der Grinten N.V. Magnetic roller
US4089297A (en) * 1975-10-07 1978-05-16 Konishiroku Photo Industry Co., Ltd. Developing apparatus of magnetic brush type for electrophotographic reproduction
US4102305A (en) * 1977-07-01 1978-07-25 Xerox Corporation Development system with electrical field generating means
DE2832695A1 (de) * 1977-08-03 1979-02-08 Hitachi Metals Ltd Maschine zur bildentwicklung
US4149488A (en) * 1977-02-17 1979-04-17 Siemens Aktiengesellschaft Deflecting guide for developer mixture
US4166263A (en) * 1977-10-03 1979-08-28 Hitachi Metals, Ltd. Magnetic core assembly for magnetizing columnar permanent magnet for use in electrostatic developing apparatus
US4167718A (en) * 1977-10-03 1979-09-11 Hitachi Metals, Ltd. Dies set for magnetizing outer surface of magnetic column
US4168481A (en) * 1977-10-05 1979-09-18 Hitachi Metals, Ltd. Core assembly for magnetizing columnar permanent magnet for use in an electrostatic developing apparatus
US4169998A (en) * 1977-10-03 1979-10-02 Hitachi Metals, Ltd. Iron core assembly for magnetizing columnar permanent magnets for use in electrostatic developing apparatus
EP0024110A1 (en) * 1979-07-16 1981-02-25 Minnesota Mining And Manufacturing Company Multiple roll developing apparatus
US4266328A (en) * 1977-10-05 1981-05-12 Hitachi Metals, Ltd. Developing roll for use in electrostatic developing apparatus employing magnetic particles
US4267245A (en) * 1979-07-25 1981-05-12 Minolta Camera Kabushiki Kaisha Method of removing foreign materials from magnetic developers
US4267248A (en) * 1978-02-24 1981-05-12 Hitachi Metals, Ltd. Magnet-brush development process of electric pattern images
EP0027729A3 (en) * 1979-10-19 1981-05-20 Xerox Corporation Apparatus for developing an electrostatic latent image
US4277552A (en) * 1978-03-23 1981-07-07 Hitachi Metals, Ltd. Magnetic developing process and toner containing high coercive force magnetic powder
US4389478A (en) * 1980-01-07 1983-06-21 Bell & Howell Company Apparatus for and methods of making bimodal electrophotographic copies
US4454520A (en) * 1982-06-24 1984-06-12 Honeywell Inc. Electrographic recorder with enhanced writing speed
US4453492A (en) * 1982-08-12 1984-06-12 E. I. Du Pont De Nemours And Company Magnetic developing unit with improved toner decorator for magnetic printing
US4496232A (en) * 1980-01-07 1985-01-29 Bell & Howell Apparatus for and methods of making bimodal electrophotographic copies
US4834871A (en) * 1986-10-31 1989-05-30 Khd Humboldt Wedag Ag Magnet block arrangement having an outwardly-directed field
US4839690A (en) * 1985-09-17 1989-06-13 Canon Kabushiki Kaisha Image bearing member usable with image forming apparatus
DE4012698A1 (de) * 1989-04-20 1990-10-25 Minolta Camera Kk Magnetische rolle zur verwendung in einem entwicklungsgehaeuse
US5494172A (en) * 1994-05-12 1996-02-27 Miller Compressing Company Magnetic pulley assembly
US20160310962A1 (en) * 2016-07-07 2016-10-27 Bunting Magnetics Co. Magnetic Roll

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE1152071B (de) * 1959-01-02 1963-08-01 Rheinische Daunendecken Fabrik Schlafsack
DE2620660A1 (de) * 1975-05-15 1976-12-02 Kip Kk Trockenentwicklerteilchen zur verwendung in der elektrofotografie und verfahren zum entwickeln von elektrostatischen bildern mit solchen teilchen
NL7509870A (nl) * 1975-08-20 1977-02-22 Oce Van Der Grinten Nv Magneetrol.

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3040704A (en) * 1957-04-16 1962-06-26 Rca Corp Apparatus for developing electrostatic printing
US3191106A (en) * 1959-12-24 1965-06-22 Baermann Max Rubber-like permanent magnet article and manufacture of same
FR1417724A (fr) * 1963-12-18 1965-11-12 Kalle Ag Rouleau magnétique pour l'électrophotographie
US3219014A (en) * 1962-12-04 1965-11-23 Xerox Corp Mechanical shield to protect magnetic core in xerographic developing apparatus
GB1071697A (en) * 1963-12-18 1967-06-14 Kalle Ag Magnetic roller for use in the development of latent electrostatic images

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3040704A (en) * 1957-04-16 1962-06-26 Rca Corp Apparatus for developing electrostatic printing
US3191106A (en) * 1959-12-24 1965-06-22 Baermann Max Rubber-like permanent magnet article and manufacture of same
US3219014A (en) * 1962-12-04 1965-11-23 Xerox Corp Mechanical shield to protect magnetic core in xerographic developing apparatus
FR1417724A (fr) * 1963-12-18 1965-11-12 Kalle Ag Rouleau magnétique pour l'électrophotographie
GB1071697A (en) * 1963-12-18 1967-06-14 Kalle Ag Magnetic roller for use in the development of latent electrostatic images

Cited By (46)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3584601A (en) * 1968-10-28 1971-06-15 Xerox Corp Magnetic brush belt development
US3882821A (en) * 1969-03-08 1975-05-13 Canon Kk Developing device for electrophotography
US3641980A (en) * 1969-10-20 1972-02-15 Xerox Corp Development apparatus
US3643629A (en) * 1969-10-20 1972-02-22 Minnesota Mining & Mfg Magnetic powder applicator
DE2224624A1 (de) * 1971-05-21 1972-11-30 Hitachi Metals Ltd Entwicklungsvorrichtung für eine elektrostatische Aufzeichnung
US3828730A (en) * 1971-05-21 1974-08-13 Hitachi Metals Ltd Electrostatic record developing apparatus
JPS496932A (enrdf_load_html_response) * 1972-01-26 1974-01-22
US3823688A (en) * 1972-01-26 1974-07-16 Xerox Corp Magnetic brush assembly
US3968773A (en) * 1972-05-22 1976-07-13 Xerox Corporation Magnetic brush developing apparatus
US4040387A (en) * 1972-09-24 1977-08-09 Mita Industrial Co. Ltd. Electrostatic photographic copying apparatus
US3911865A (en) * 1973-03-30 1975-10-14 Xerox Corp Toner pickoff apparatus
US3937181A (en) * 1973-05-23 1976-02-10 Fuji Xerox Co., Ltd. Magnetic brush type developing mechanism in electrophotographic copying machine
US3892908A (en) * 1973-06-25 1975-07-01 Minnesota Mining & Mfg Coating of solid substrates with magnetically propelled particles
US3863603A (en) * 1974-01-07 1975-02-04 Ibm Magnetic brush roll having resilient polymeric surface
US3981271A (en) * 1974-02-20 1976-09-21 Fuji Xerox Co., Ltd. Magnetic brush type developer for use in an electrophotographic machine
DE2523811A1 (de) * 1974-05-28 1975-12-18 Minnesota Mining & Mfg Verfahren und einrichtung zum auftragen eines farbpulvers auf ein elektrographisches aufzeichungsmittel
JPS518745U (enrdf_load_html_response) * 1974-07-05 1976-01-22
JPS5143147A (enrdf_load_html_response) * 1974-10-11 1976-04-13 Hitachi Metals Ltd
US3952701A (en) * 1974-11-05 1976-04-27 Hitachi Metals, Ltd. Electrostatic developing apparatus
US3950089A (en) * 1975-02-24 1976-04-13 Xerox Corporation Coated roll for magnetic brush development and cleaning systems
US4089297A (en) * 1975-10-07 1978-05-16 Konishiroku Photo Industry Co., Ltd. Developing apparatus of magnetic brush type for electrophotographic reproduction
US4068622A (en) * 1975-10-22 1978-01-17 Oce-Van Der Grinten N.V. Magnetic roller
US4149488A (en) * 1977-02-17 1979-04-17 Siemens Aktiengesellschaft Deflecting guide for developer mixture
US4102305A (en) * 1977-07-01 1978-07-25 Xerox Corporation Development system with electrical field generating means
DE2832695A1 (de) * 1977-08-03 1979-02-08 Hitachi Metals Ltd Maschine zur bildentwicklung
US4166263A (en) * 1977-10-03 1979-08-28 Hitachi Metals, Ltd. Magnetic core assembly for magnetizing columnar permanent magnet for use in electrostatic developing apparatus
US4167718A (en) * 1977-10-03 1979-09-11 Hitachi Metals, Ltd. Dies set for magnetizing outer surface of magnetic column
US4169998A (en) * 1977-10-03 1979-10-02 Hitachi Metals, Ltd. Iron core assembly for magnetizing columnar permanent magnets for use in electrostatic developing apparatus
US4168481A (en) * 1977-10-05 1979-09-18 Hitachi Metals, Ltd. Core assembly for magnetizing columnar permanent magnet for use in an electrostatic developing apparatus
US4266328A (en) * 1977-10-05 1981-05-12 Hitachi Metals, Ltd. Developing roll for use in electrostatic developing apparatus employing magnetic particles
US4267248A (en) * 1978-02-24 1981-05-12 Hitachi Metals, Ltd. Magnet-brush development process of electric pattern images
US4277552A (en) * 1978-03-23 1981-07-07 Hitachi Metals, Ltd. Magnetic developing process and toner containing high coercive force magnetic powder
EP0024110A1 (en) * 1979-07-16 1981-02-25 Minnesota Mining And Manufacturing Company Multiple roll developing apparatus
US4266868A (en) * 1979-07-16 1981-05-12 Minnesota Mining And Manufacturing Company Multiple roll developing apparatus
US4267245A (en) * 1979-07-25 1981-05-12 Minolta Camera Kabushiki Kaisha Method of removing foreign materials from magnetic developers
EP0027729A3 (en) * 1979-10-19 1981-05-20 Xerox Corporation Apparatus for developing an electrostatic latent image
US4389478A (en) * 1980-01-07 1983-06-21 Bell & Howell Company Apparatus for and methods of making bimodal electrophotographic copies
US4496232A (en) * 1980-01-07 1985-01-29 Bell & Howell Apparatus for and methods of making bimodal electrophotographic copies
US4454520A (en) * 1982-06-24 1984-06-12 Honeywell Inc. Electrographic recorder with enhanced writing speed
US4453492A (en) * 1982-08-12 1984-06-12 E. I. Du Pont De Nemours And Company Magnetic developing unit with improved toner decorator for magnetic printing
US4839690A (en) * 1985-09-17 1989-06-13 Canon Kabushiki Kaisha Image bearing member usable with image forming apparatus
US4834871A (en) * 1986-10-31 1989-05-30 Khd Humboldt Wedag Ag Magnet block arrangement having an outwardly-directed field
DE4012698A1 (de) * 1989-04-20 1990-10-25 Minolta Camera Kk Magnetische rolle zur verwendung in einem entwicklungsgehaeuse
US5494172A (en) * 1994-05-12 1996-02-27 Miller Compressing Company Magnetic pulley assembly
US20160310962A1 (en) * 2016-07-07 2016-10-27 Bunting Magnetics Co. Magnetic Roll
US9962710B2 (en) * 2016-07-07 2018-05-08 Bunting Magnetics Co. Magnetic roll

Also Published As

Publication number Publication date
FR1566007A (enrdf_load_html_response) 1969-05-02
GB1216915A (en) 1970-12-23
SE335476B (enrdf_load_html_response) 1971-05-24
DE1752408A1 (de) 1971-11-11

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