US3219014A - Mechanical shield to protect magnetic core in xerographic developing apparatus - Google Patents

Mechanical shield to protect magnetic core in xerographic developing apparatus Download PDF

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Publication number
US3219014A
US3219014A US242251A US24225162A US3219014A US 3219014 A US3219014 A US 3219014A US 242251 A US242251 A US 242251A US 24225162 A US24225162 A US 24225162A US 3219014 A US3219014 A US 3219014A
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United States
Prior art keywords
shield
magnetic
image
developer
layer
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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
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US242251A
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English (en)
Inventor
George R Mott
Harold E Clark
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.)
Xerox Corp
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Xerox Corp
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Publication date
Application filed by Xerox Corp filed Critical Xerox Corp
Priority to US242251A priority Critical patent/US3219014A/en
Priority to GB47944/63A priority patent/GB1034099A/en
Priority to FR956073A priority patent/FR1393298A/fr
Priority to DE1497076A priority patent/DE1497076C3/de
Application granted granted Critical
Publication of US3219014A publication Critical patent/US3219014A/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
    • 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
    • G03G15/0928—Details concerning the magnetic brush roller structure, e.g. magnet configuration relating to the shell, e.g. structure, composition

Definitions

  • an electrostatic latent image In xerography, it is usual to form an electrostatic latent image on a surface.
  • One method of doing this is to charge a photoconductive insulating surface and then dissipate the charge selectively by exposure to a pattern of activating radiation as set forth, for example, in U.S. 2,297,691 to Chester F. Carlson.
  • Other means of forming electrostatic latent images are set forth in US. 2,647,- 464 to James P. Ebert. Whether formed by these means or any other, the resulting electrostatic charge pattern is conventionally utilized by the deposition of an electroscopic material thereon through electrostatic attraction whereby there is formed a visible image of electroscopic particles corresponding to the electrostatic latent image.
  • the electrostatic charge pattern may be transferred to an insulating film and the electroscopic particles deposited thereon to form the visible image.
  • this visible image in turn, may be transferred to a second surface to form a xerographic print or may be affixed directly to the surface on which it is developed.
  • a process of applying the developer to the latent electrostatic image is set forth in US. 2,618,552 to E. N. Wise and involves the use of a finely-divided colored material called a toner deposited on a slightly more coarsely divided material called a carrier. This twocomponent developer is cascaded across the electrostatic image areas. To produce a positive of the electrostatic image, a toner and carrier are selected such that the toner will be charged to a polarity opposite to that of the electrostatic image, the carrier being charged to the same polarity as the electrostatic image.
  • Another form of developer mix is composed of a toner and a ferro-magnetic carrier material controlled by means of a magnet.
  • This forms streamers of the developer which constitute a brush-like mass and the brush is passed over the surface bearing the electrostatic latent image whereby the brush contacts the image bearing surface.
  • Development by this means is termed magnetic brush development.
  • the toner is triboelectrically charged and deposits on the electrostatic latent image in a manner similar to that wherein the toner and carrier mix is cascaded across the image-bearing surface.
  • Variations on the use of ferro-magnetic developer are set forth, for example, in US. 2,846,333 to Wilson and US. 3,015,- 305 to Hall et al.
  • the prior disadvantages can be overcome by employing an electrically conductive shield supported about the magnet.
  • the bias effect can be achieved by applying the bias potential to the shield instead of the magnet.
  • the shield of a conductive exterior integrally supported on an insulating material, the benefits of the insulating material can be selectively utilized as to broaden the range of development application independent of the electrical properties of the magnet. Since the magnetic member does not per se support the developer, cleaning can be effected simply by removing the magnet from the shield or vice versa.
  • FIG. 1 is a longitudinal section of a hand device for applying the devloper particles to an electrostatic latent image to be developed
  • FIG. 2 is a fragmentary section through a modified form of shield as may be used with the apparatus of FIG. 1;
  • FIG. 3 is a side-sectional view of an embodiment of automatic apparatus for effecting development in accordance with the invention.
  • FIG. 4 is a top plan view partly in section of the embodiment of FIG. 3.
  • the apparatus to be described, embodying the invention in illustrative form, may be operated with a developer comprising a toner powder and a carrier material.
  • the carrier material consists of magnetically attractable powders such as magnetic ferrites as described in U.S. patents to J. L. Snoeck No. 2,452,529; 2,452,530 and 2,452,531 all dated October 26, 1948, iron carbonyl, alcholized iron, etc., while any of the large number of toner materials known to those skilled in the art such as those described in U.S. 2,618,551 to L. E. Walkup, U.S. 2,618,- 552 to E. N. Wise and U.S. 2,753,308 to R. B. Landrigan are suitable for mixing with the magnetic carrier to form a developer to be employed in the present invention.
  • the ferrites developed by Snoeck described above may also be used as single component magnetic developers, i.e., the ferrite may act as both carrier and toner. (See Wilson patent, surpra.)
  • alcoholized iron is used as the magnetic carrier, it is possible to develop a reversal image or a direct image by selecting a toner above or below iron in the triboelectric series.
  • powdered shellac or rosin each pigmented with a suitable material such as carbon black, when used with alcoholized iron give a direct image with a negative charged surface and a reversed image with a positively charged surface.
  • Vinsol resin an extract from long leaf yellow pine stumps composed principally of an oxidized form of abietic acid and manufactured by Hercules Powder Company, Wilmington, Delaware
  • a suitable dye such as nigrosine gives a direct image with a positively charged surface and a reversed image with a negatively charged surface.
  • the toner may be kept the same and the magnetic carrier varied to obtain a direct or reversed reproduction of the electrostatic image.
  • a polystyrene resin with a suitable pigment as carbon black for the toner one can obtain a direct image of a negatively charged surface when using PMC Z270, a powdered iron produced by Xerox Corporation, Rochester, New York, as the magnetic carrier and a reversed reproduction of the negatively charged image when using Carbonyl-L, a powdered iron made by the reduction of an iron carbonyl by Antara Chemicals Division of General Aniline and Film Corporation, New York, New York, as the magnetic carrier.
  • FIG. 1 a magnetic brush, designated 10, for developing electrostatic latent images in accordance with the inven tion.
  • the brush is comprised of a bar magnet 11 surrounded by a box-like shield 13 that is non-magnetic and yet electrically conductive.
  • the shield may be of metal or the like and on which there is a terminal 14 for connecting a lead wire 15 thereto from a source of potential 16 via a switch 13.
  • a potentiometer 17 In order to vary the magnitude of the potential from the source, there is provided a potentiometer 17 and for connecting the brush operatively to ground or bias potential, there is provided a double throw switch 18. By means of a selector switch 22, either polarity of potential may selectively be applied.
  • a reversal reproduction, controlled background development, or image enhancement may be effected by applying the appropriate magnitude and polarity of bias potential to the shield. Connecting potentials on the order of back ground potential and of the same polarity, will effect background suppression, while potentials of the same polarity and the same or greater magnitude as the image potentials result in a reversal reproduction.
  • developer 21 which may be of any of the above-described types, is retained by the magnetic field created by the magnet 11 along the underside of the conductive shield 13. Development is effected by moving the brush suppotring a quantity of developer particles 21 across the surface of an image-bearing member such as a xerographic plate on which an electrostatic latent image has previously been formed.
  • Extending around the shield is a horizontal flange 27 of non-magnetic material that extends sufliciently far from the magnetic field such that the magnetic field at the extremities of the flange is too weak to retain developer particles.
  • This serves a useful function and eliminates the almost impossible requirement of wiping or scraping used developer from the brush to clean the member. Instead, removal of used developer is effected by merely raising the magnet above the flange causing the magnetic particles to drop off because of inability to creep over the flange.
  • an electrically insulating rod 25 attached to the magnet and which includes a knurled knob 26 for hand gripping.
  • the interior base layer of the shield designated 28, is comprised of a non-magnetic and electrically insulating material such as a plastic, glass, glass-fiber, plastic laminate, etc.
  • a layer 29 which may comprise the exterior of the shield and consists of a non'magnetic electrically conductive material such as metal, conductive paint or other similar electrically conductive coating.
  • the conductive layer 29 can be energized with a reference potential, which includes ground or bias, in a similar manner as described above in connection with FIG. 1.
  • this embodiment further enhances the developing properties of the brush by extending the range of image forms with which the brush has maximum utility.
  • non-magnetic a material which does not interfere with the liens of force of a magnetic field, i.e., a material having a permeability not substantially different from that of free space.
  • Magnetic brush development is truly a specie of cascade development. As used in the instant invention, it dilfers primarily in that a magnet is used to effect adherence to the presenting surface which carries the carrier-toner mixture over the surface of a xerographic plate, rather than the force of gravity.
  • the carrier in magnetic brush development therefore, is magnetic and generally ferromagnetic. As such, this magnetic carrier is, itself, frequently conductive and hence the mixture of a carrier and toner is frequently somewhat conductive, rather than purely insulating.
  • the mass of developer i.e., toner-carrier mixture
  • the deposition of toner is thus uniform over large image areas.
  • a xerographic plate has been exposed so as to reduce the non-image areas completely to zero, the result will be a black-on-gray reproduction of the original, rather than a black-on-white as desired. Regulating exposure to this extent, particularly when the copy to be reproduced consists of variable quality subjects, is very difficult.
  • this embodiment enables not only the biasing benefit afforded by employment of a conductive shield but in addition, utility of the magnetic brush element is enhanced by having selectively available the benefit of an insulating material interposed between an image-bearing plate and the magnet.
  • FIGS. 3 and 4 there is illustrated an embodiment of automatic apparatus operable in accordance with the invention.
  • the particular embodiment is to be described as operable with a rotating shield member relative to a stationary magnet which may be a permanent magnet or an electromagnet of any suitable geometrical configuration as is known in the art. It is to be understood and to be considered as part of this invention that alternatively, a stationary shield of the type described above could be employed with a rotating magnet or either one or the other or both may move relative to the other.
  • a magnetic brush device for developing an electrostatic image on an image-bearing plate 40 which may be a xerographic plate having a photoconductive surface on a conductive backing.
  • the surface of the plate contains an electrostatic latent image prepared by any of the means known to those skilled in the art as, for example, those set forth in US. 2,297,691 to Chester F. Carlson.
  • the plate is adapted to be continuously advanced along a predetermined path to pass through the usual xerographic processing stations including sensitizing, exposure and fixing as is known in the art but not illustrated in the drawings.
  • the plate is shown to be constructed of flexible material issuing from a supply reel 41 from which it is continuously drawn onto a take-up reel 42 being driven by motor 43.
  • Suitable means such as a slip-clutch or the like (not shown), may be provided between the motor and the take-up reel in order to maintain the velocity of the plate substantially constant.
  • a slip-clutch or the like may be provided between the motor and the take-up reel in order to maintain the velocity of the plate substantially constant.
  • the image-bearing member or plate with which this invention is used may comprise any of a variety of forms known in the art.
  • the surface layer supporting the image may be comprised of an insulating material, such as polystyrene capable of retaining a charge pattern for a reasonable period of time, or it may comprise a photoconductive insulating material such as vitreous selenium, a dispersion of zinc oxide in an insulating binder, or various other materials known in the art of xerography.
  • the backing substrate may comprise any suitable mechanical support, whether rigid or flexible such as metal, conductive paper, or the like.
  • the substrate may be dispensed with where the insulating layer, itself, has adequate strength.
  • the developing apparatus 35 is supported adjacent the path of movement of the xerographic plate to present developing particles to the plate surface during the course of plate movement.
  • the developing apparatus is comprised of an elongated permanent magnet extending widthwise of the plate and secured to station ary rod supports 51 and 52, in turn secured to stationary support blocks 53 and 54.
  • a cylindrical shield 55 which is non-magnetic and containing an electrically conductive material similar in construction to the shield of either FIG. 1 or FIG. 2.
  • the shield 55 has a cross sectional diameter sufficiently large to encompass the magnetic member while the ends are of smaller diameter to form sleeve sections 56 and 57 having electrically insulating bushings 62 and 63 for mounting on the outer race of ball-bearings 58 and 59, respectively, which in turn pressfit onto rods 51 and 52, respectively.
  • the shield is formed of two semi-cylindrical mating sections connected by means of two resilient spring hasps and 61. By drawing at the opposite sections, the individual sections are separable to enable convenient removal of the shield from the bearings and likewise they may be joined in assembled relation -by pressing them together when appropriately arranged.
  • the sleeve can be mounted on one end instead of two. This latter method permits an integral shield which can be slipped onto the single mount.
  • Rotation of the shield is eifected by means of a motor 43, the output shaft of which securely supports a pulley driving a timing belt 71 connected to a toothed or ribbed portion 72 on sleeve 57.
  • a motor 43 the output shaft of which securely supports a pulley driving a timing belt 71 connected to a toothed or ribbed portion 72 on sleeve 57.
  • the rotational speed is dependent on several factors including developer being employed, plate being developed, etc. Speeds on the order of approximately /2 to 2 /2 inches per second are usually suitable with up to about 1 /2 inches per second being preferred.
  • the outer or exterior surface of shield 55 is not smooth but rather is roughened in a random or regular pattern such that the surface roughness serves to hold magnetic developer 21 in place and prevent its sliding along the surface as the shield rotates upwardly in this
  • the texture of the sleeve surface may be inherently rough as by using a uniform checkerboard rough pattern on the backside. Otherwise, the texture may be formed rough as by molding a plastic shield against a wire screen and removing the wire screen once the shield material has hardened. Sandblasting has also been found a convenient method of forming a roughened surface as long as provisions are taken to provide for uniform roughness along the top surface and such roughness provides a sufiicient friction coefficient to carry developer particles during rotation of the shield.
  • uniformity in roughness is desired so that uniformity of developer presentation results, thereby constantly supplying during operation a uniform supply of developer particles to the surface of the image-bearing member. Therefore, any known means for accomplishing uniform roughness of the shield surface is intended to be encompassed within this invention.
  • the shield 55 is mounted to rotate about its axis in the direction shown by the arrow and about magnet Stl.
  • the magnet 54 which may be of alnico, remains stationary with one of its poles (shown as the north pole) as close to the inner surface of shield 55 as possible to produce a magnetic field thereabout while the south magnetic pole is spaced from the inner surface of the shield to produce a weakened or no magnetic field at the shield surface.
  • the field strength generated by the pole close to the inner surface and to the left of line AA assures that the magnetic field strength to the left of the line is sufficient to cause developer to cling to the surface while to the right of the line A-A, there is insufficient field strength to retain developer on the shield surface.
  • the developing material 21, which is contained in a trough 73, is magnetically picked up by the rotating shield as the periphery of the shield moves over the trough. Thereafter, the developer particles are arranged into a brush-like array and carried upwardly or downwardly, as the case may be, to be brushed across the electrostatic latent image on surface 40, shown moving in a direction opposite to the direction of shield rotation. This then causes the image to be developed, after which the developing particles still remaining on the shield surface drop off as the surface continues to rotate beyond the magnetic field. By this means, there is produced a continuous cycle of attracting developer, brushing the developer across the image, and then returning the developer to its source of supply.
  • a toner supply 74 is maintained in toner dispenser 75 which dispenses a controlled quantity of toner into the trough.
  • the developer in the trough is constantly agitated and mixed such that the brush continually presents replenished developer to the electrostatic image to assure uniform development density of each succeeding image.
  • the apparatus can be simply adapted by merely separating the two semi-cylindrical sections of the shield maintained together by spring hasps 60 and 61.
  • the trough as shown is conveniently provided with a hinged bottom wall 80 supported by a hinge 81 and a hasp 82 such that developer contained therein may be easily and simply dumped by opening the hasp. Subsequently, a developer of a different type may be substituted while a new shield is mounted about the magnetic member 50.
  • dispenser may also have means provided for conveniently dumping the toner 74 and substituting a toner of a different composition assuming, of course, that developer is employed including toner as a separate component.
  • sleeve 56 contains a conductive ring-collar 76 integral therewith and to which a sliding contact is made by a shoe 77.
  • the shoe is connected via a lead wire 15 through a switch 18 and to a potentiometer 17 to a potential source 16.
  • the shield 55 is electrically conductive in the manner of FIG. 1 or further, is formed of the insulating layer or layers of FIG. 2, ground, electrical bias, or an electrical isolation can be achieved as described above in accordance with the results sought to be achieved.
  • Apparatus for developing electrostatic latent images previously formed on the surface of a support member comprising in combination:
  • switch means including bias potential, neutral, and ground source contacts to selectively connect said terminal
  • (e) means to support a quantity of magnetic powder developer particles for supply to said shield.
  • Apparatus for developing electrostatic latent images previously formed on the surface of a support member comprising in combination:
  • a first layer of electrically insulating material in close spaced relation to the magnetic field producing means (2) a second layer of electrically conductive material overlying said first recited layer; and, (3) a third layer of electrically insulating material overlying said conductive layer and capable of retaining magnetic powder developer particles attracted thereto by the field producing means for presentation to the surface of an image support member;
  • a terminal for connecting a reference potential to said electrically conductive layer (d) switch means including bias potential, neutral, and ground source contacts to selectively connect said terminal; and,
  • (e) means to support a quantity of magnetic powder developer particles for supply to said shield.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Magnetic Brush Developing In Electrophotography (AREA)
US242251A 1962-12-04 1962-12-04 Mechanical shield to protect magnetic core in xerographic developing apparatus Expired - Lifetime US3219014A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
US242251A US3219014A (en) 1962-12-04 1962-12-04 Mechanical shield to protect magnetic core in xerographic developing apparatus
GB47944/63A GB1034099A (en) 1962-12-04 1963-12-04 Improvements in xerographic developing apparatus
FR956073A FR1393298A (fr) 1962-12-04 1963-12-04 Appareil de développement xérographique
DE1497076A DE1497076C3 (de) 1962-12-04 1963-12-04 Elektrofotografische Entwicklungsvorrichtung

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US242251A US3219014A (en) 1962-12-04 1962-12-04 Mechanical shield to protect magnetic core in xerographic developing apparatus

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Cited By (18)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3455276A (en) * 1967-05-23 1969-07-15 Minnesota Mining & Mfg Magnetically responsive powder applicator
US3648657A (en) * 1968-06-03 1972-03-14 Xerox Corp Electrostatic image development apparatus
DE2227709A1 (de) * 1971-06-11 1972-12-28 Xerox Corp Elektrostatische Kopiermaschine
US3823688A (en) * 1972-01-26 1974-07-16 Xerox Corp Magnetic brush assembly
DE2403186A1 (de) * 1973-01-24 1974-08-01 Ricoh Kk Entwicklungssystem
US3852770A (en) * 1973-05-21 1974-12-03 Minnesota Mining & Mfg Coded legend marking assembly having transmit and receive printing circuitry
US3866564A (en) * 1973-04-25 1975-02-18 Xerox Corp Magnetic brush developing apparatus for copiers
US3914771A (en) * 1973-11-14 1975-10-21 Minnesota Mining & Mfg Electrographic recording process and apparatus employing synchronized recording pulses
US4002145A (en) * 1973-08-16 1977-01-11 Develop Kg/Dr. Eisbein And Co. Apparatus for applying and fixing a magnetizable powder on a charged sheet
US4076857A (en) * 1976-06-28 1978-02-28 Eastman Kodak Company Process for developing electrographic images by causing electrical breakdown in the developer
US4165393A (en) * 1975-11-26 1979-08-21 Ricoh Co., Ltd. Magnetic brush developing process for electrostatic images
US4218691A (en) * 1977-08-30 1980-08-19 Ricoh Company, Ltd. Recording apparatus with improved counter electrode
DE3014849A1 (de) * 1979-04-20 1980-11-06 Canon Kk Entwicklungseinrichtung und verfahren zur herstellung derselben
EP0060030A2 (de) * 1981-02-24 1982-09-15 Ing. C. Olivetti & C., S.p.A. Elektrofotografische Kopiereinrichtung
DE3140478A1 (de) * 1980-10-11 1982-11-18 Canon K.K., Tokyo Entwicklungsvorrichtung
US5315325A (en) * 1991-08-20 1994-05-24 Recycling Technologies International Corporation Laser printer cartridges
US6341420B1 (en) 2000-08-02 2002-01-29 Static Control Components, Inc. Method of manufacturing a developer roller
US9557686B2 (en) * 2015-04-24 2017-01-31 Flo-Tech, Llc Spring bearing for use in a developer cartridge roller system

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS4826140A (de) * 1971-08-05 1973-04-05
JPS516730A (ja) * 1974-07-09 1976-01-20 Konishiroku Photo Ind Denshishashinfukushahoniokeru genzohoho
US4187330A (en) * 1976-01-30 1980-02-05 Hitachi Metals, Ltd. Electrostatic developing method and apparatus using conductive magnetic toner
NL7601285A (nl) * 1976-02-09 1977-08-11 Mita Industrial Co Ltd Werkwijze en inrichting voor het elektrofotogra- fisch of elektrostatisch drukken.
US4018187A (en) * 1976-06-30 1977-04-19 International Business Machines Corporation Grooved magnetic brush roll
JPS5368244A (en) * 1976-11-29 1978-06-17 Sharp Corp Developing device
US4422749A (en) * 1980-10-11 1983-12-27 Canon Kabushiki Kaisha Developing apparatus
US4537491A (en) * 1981-10-20 1985-08-27 Ricoh Company, Ltd. Development apparatus for developing latent electrostatic images
US4669859A (en) * 1982-03-23 1987-06-02 Ricoh Company, Ltd. Developing device

Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1714171A (en) * 1926-01-12 1929-05-21 August F Jobke Magnetic separator
US2791949A (en) * 1956-02-01 1957-05-14 Haloid Co Xerographic copying device
US2846333A (en) * 1955-11-01 1958-08-05 Haloid Xerox Inc Method of developing electrostatic images
US2890968A (en) * 1955-06-02 1959-06-16 Rca Corp Electrostatic printing process and developer composition therefor
US2992733A (en) * 1957-10-09 1961-07-18 Indiana General Corp Magnetic pulley and permanent magnet therefor
US3015305A (en) * 1958-05-23 1962-01-02 Xerox Corp Development of electrostatic images
US3040704A (en) * 1957-04-16 1962-06-26 Rca Corp Apparatus for developing electrostatic printing
US3088386A (en) * 1959-11-16 1963-05-07 American Photocopy Equip Co Electrophotographic photocopy machine
US3117884A (en) * 1955-03-23 1964-01-14 Rca Corp Electrostatic printing process and apparatus

Patent Citations (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US1714171A (en) * 1926-01-12 1929-05-21 August F Jobke Magnetic separator
US3117884A (en) * 1955-03-23 1964-01-14 Rca Corp Electrostatic printing process and apparatus
US2890968A (en) * 1955-06-02 1959-06-16 Rca Corp Electrostatic printing process and developer composition therefor
US2846333A (en) * 1955-11-01 1958-08-05 Haloid Xerox Inc Method of developing electrostatic images
US2791949A (en) * 1956-02-01 1957-05-14 Haloid Co Xerographic copying device
US3040704A (en) * 1957-04-16 1962-06-26 Rca Corp Apparatus for developing electrostatic printing
US2992733A (en) * 1957-10-09 1961-07-18 Indiana General Corp Magnetic pulley and permanent magnet therefor
US3015305A (en) * 1958-05-23 1962-01-02 Xerox Corp Development of electrostatic images
US3088386A (en) * 1959-11-16 1963-05-07 American Photocopy Equip Co Electrophotographic photocopy machine

Cited By (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3455276A (en) * 1967-05-23 1969-07-15 Minnesota Mining & Mfg Magnetically responsive powder applicator
US3648657A (en) * 1968-06-03 1972-03-14 Xerox Corp Electrostatic image development apparatus
DE2227709A1 (de) * 1971-06-11 1972-12-28 Xerox Corp Elektrostatische Kopiermaschine
US3805739A (en) * 1971-06-11 1974-04-23 Xerox Corp Controlling multiple voltage levels for electrostatic printing
US3823688A (en) * 1972-01-26 1974-07-16 Xerox Corp Magnetic brush assembly
DE2403186A1 (de) * 1973-01-24 1974-08-01 Ricoh Kk Entwicklungssystem
US3866564A (en) * 1973-04-25 1975-02-18 Xerox Corp Magnetic brush developing apparatus for copiers
US3852770A (en) * 1973-05-21 1974-12-03 Minnesota Mining & Mfg Coded legend marking assembly having transmit and receive printing circuitry
US4002145A (en) * 1973-08-16 1977-01-11 Develop Kg/Dr. Eisbein And Co. Apparatus for applying and fixing a magnetizable powder on a charged sheet
US3914771A (en) * 1973-11-14 1975-10-21 Minnesota Mining & Mfg Electrographic recording process and apparatus employing synchronized recording pulses
US4165393A (en) * 1975-11-26 1979-08-21 Ricoh Co., Ltd. Magnetic brush developing process for electrostatic images
US4076857A (en) * 1976-06-28 1978-02-28 Eastman Kodak Company Process for developing electrographic images by causing electrical breakdown in the developer
US4218691A (en) * 1977-08-30 1980-08-19 Ricoh Company, Ltd. Recording apparatus with improved counter electrode
DE3014849A1 (de) * 1979-04-20 1980-11-06 Canon Kk Entwicklungseinrichtung und verfahren zur herstellung derselben
DE3140478A1 (de) * 1980-10-11 1982-11-18 Canon K.K., Tokyo Entwicklungsvorrichtung
EP0060030A2 (de) * 1981-02-24 1982-09-15 Ing. C. Olivetti & C., S.p.A. Elektrofotografische Kopiereinrichtung
EP0060030A3 (de) * 1981-02-24 1982-12-01 Ing. C. Olivetti & C., S.p.A. Elektrofotografische Kopiereinrichtung
US4486091A (en) * 1981-02-24 1984-12-04 Ing. C. Olivetti & C., S.P.A. Electrophotographic copier
US5315325A (en) * 1991-08-20 1994-05-24 Recycling Technologies International Corporation Laser printer cartridges
US6341420B1 (en) 2000-08-02 2002-01-29 Static Control Components, Inc. Method of manufacturing a developer roller
US9557686B2 (en) * 2015-04-24 2017-01-31 Flo-Tech, Llc Spring bearing for use in a developer cartridge roller system

Also Published As

Publication number Publication date
GB1034099A (en) 1966-06-29
DE1497076B2 (de) 1976-01-02
DE1497076A1 (de) 1969-03-27
DE1497076C3 (de) 1980-08-28

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