US3818864A - Image developing apparatus - Google Patents

Image developing apparatus Download PDF

Info

Publication number
US3818864A
US3818864A US00180426A US18042671A US3818864A US 3818864 A US3818864 A US 3818864A US 00180426 A US00180426 A US 00180426A US 18042671 A US18042671 A US 18042671A US 3818864 A US3818864 A US 3818864A
Authority
US
United States
Prior art keywords
toner particles
electrode
electrode means
electrostatic
uniformly
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
US00180426A
Other languages
English (en)
Inventor
J Bickmore
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
Original Assignee
Xerox Corp
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 Xerox Corp filed Critical Xerox Corp
Priority to US00180426A priority Critical patent/US3818864A/en
Priority to CA147,737A priority patent/CA980181A/en
Priority to DE2239207A priority patent/DE2239207A1/de
Priority to NL7212332A priority patent/NL7212332A/xx
Priority to GB4232272A priority patent/GB1406292A/en
Priority to JP47092213A priority patent/JPS4838735A/ja
Priority to US452152A priority patent/US3908037A/en
Application granted granted Critical
Publication of US3818864A publication Critical patent/US3818864A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • 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
    • G03G15/0801—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer for cascading
    • 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
    • G03G15/0806—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer on a donor element, e.g. belt, roller
    • G03G15/0812—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer on a donor element, e.g. belt, roller characterised by the developer regulating means, e.g. structure of doctor blade
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G2215/00—Apparatus for electrophotographic processes
    • G03G2215/06—Developing structures, details
    • G03G2215/0602—Developer
    • G03G2215/0604—Developer solid type
    • G03G2215/0614—Developer solid type one-component
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G2215/00—Apparatus for electrophotographic processes
    • G03G2215/06—Developing structures, details
    • G03G2215/0634—Developing device
    • G03G2215/0636—Specific type of dry developer device
    • G03G2215/0641—Without separate supplying member (i.e. with developing housing sliding on donor member)

Definitions

  • a surface traverses a uniformly varying electric field whereby electrophotographic developer particles adhering to said surface are removed therefrom in accordance with a first portion of said electric field and fur- I 5 Claims, 3 Drawing Figures PATENIEDJUNZSXGM SHEU 1 BF 2 e e e 666 see 9 INVENIUR.
  • This invention relates to image developing techniques and more particularly to an apparatus for uniformly developing an electrostatic latent image.
  • the greatest amount of electrophotographic developer particles are deposited in image areas including the greatest charge density and conversely little or no electrophotographic developer particles are deposited in image areas where the charge density is least. Consequently a developed image is produced in conformity with the distribution of electrostatic charges on the surface of the photoconductive insulating material.
  • developed image may be subsequently transferred to a support surface to form a permanent copy.
  • the photoconductive insulating material is then prepared for reuse and'the foregoing operation is repeated.
  • the electrophotographic developer particles conventionally utilized to develop an electrostatic latent image may comprise charged toner particles such as a charcoal powder or any of a number of various carbon or lampblack materials, finely divided materialshaving added pigment such as resins containing pigment or dyes, metallic particles and generally all xerographic developer materials.
  • Such toner particles may be deposited on the electrostatic charges as by cascading a two-component developing material consisting of the toner particles which adhere to a coarse granular material, such as a glass, sand or steel bead commonly known as the carrier, over the surface of the photoconductive insulating material.
  • Other conventional developing systems direct a cloud of toner particles toward the surface of the photoconductive insulating material.
  • an apparatus for uniformly applying electrophotographic developer particles to a surface wherein said surface traverses a uniformly varying electrostatic field such that electrophotographic developer particles adhering to said Surface are removed therefrom in accordance with a first portion of said electrostatic field; and as said surface continues to traverse said electrostatic field, further electrophotographic developer particles are uniformly deposited on said surface in accordance with a second portion of said electrostatic field.
  • the uniformly varying electrostatic field is produced by resistive electrode means supplied with biassing voltages such that a uniformly varying potential is provided along said electrode means.
  • FIG. 2 illustrates another embodiment of the present invention for developing an electrostatic latent image comprised of selectively distributed electrostatic charges
  • FIG. 1 there is illustrated a diagrammatic representation of the present invention comprising electrode means 10, donor member 20 and photoconductive plate 30.
  • the donor member 20 is adapted to be rotated about an axis in the direction indicated by the arrow A and to receive a uniform layer of electrophotographic developer particles 124 on the surface 201 thereof and to transfer said electrophotographic developer particles to the surface of photoconductive plate 30.
  • the electrophotographic developer particles 124 comprise charged toner particles conventionally utilized in xerographic developing techniques.
  • Photoconductive plate 30 may comprise a conventional xerographic plate including a photoconductive insulating surface 301 overlying a conductive backing 302.
  • the photoconductive plate 30 may assume any convenient configuration, such as the illustrated drum configuration whereby the photoconductive plate 30 is adapted to rotate about an axis in the direction indicated by the arrow B.
  • the photoconductive plate 30 may assume an endless belt configuration, or the photoconductive plate 30 may be a planar member.
  • the surface 301 of photoconductive plate 30 may be comprised of photoconductive insulating material, such as selenium or any other conventional xerographic photoreceptor.
  • the conductive backing 302 is adapted to be supplied with a reference potential such as a biassing potential and a unifonn electrostatic charge is adapted to be deposited on the surface 301 of the photoconductive plate 30.
  • a reference potential such as a biassing potential
  • a unifonn electrostatic charge is adapted to be deposited on the surface 301 of the photoconductive plate 30.
  • a description of the apparatus that may be utilized in depositing a uniform electrostatic charge on surface 301 may be found in U.S. Pat. No. 2,777,957 which issued to L. E. Walkup and assigned to Xerox Corporation.
  • the uniform electrostatic charge deposited on surface 301 is adapted to be dissipated in accordance with the exposure thereof to a light image projected thereto resulting in an electrostatic latent image comprised of selectively distributed electrostatic charges 303.
  • the potential appearing at the surface 301 is a function of the density of the electrostatic charges 303 which in turn is dependent upon the intensity of light projected thereon.
  • the potential appearing at'exposed areas on the surface 301 may be on the order of volts and the potential appearing at non-exposed areas on the surface 301 may be on the order of 800 volts.
  • the bias potential supplied to the conductive backing 302 should be somewhat larger than background potential to suppress the deposition of developer particles on background areas.
  • a suitable bias potential might be 200 volts.
  • the electrostatic latent imaged comprised of the selectively distributed electrostatic charges 303 is adapted to be developed at developing station 31. A more complete description of the development of the electrostatic latent image is set forth in U.S. Pat.
  • the polarity of electrostatic charges 303 as illustrated in FIG. 1 admits of positive polarity and the polarity of the electrophotographic developer particles 124 admits of negative polarity.
  • the polarity of the electrostatic charges 303 may be negative and the polarity of the electrophotographic developer particles 124 may be positive.
  • the developed image may be transferred to a support surface such as paper in a well-known manner, not shown herein.
  • Electrode means is fixedly disposed relative to donor member and is in spaced registration from the surface 201.
  • the electrode means 10 is adapted to be coextensive with at least a portion of the surface 201 of donor member 20 and accordingly, if the donor member 20 is of a drum configuration the surface of the electrode means 10 may liein a cylindrical plane concentric with the surface 201.
  • the longitudinal dimension of the electrode means 10 is at least equal to the axial length of the donor member 20.
  • the surface of the electrode means 10 and the surface 201 admit of a face to face relationship such that a given point on the surface 201 is adapted to be rotated past the electrode means 10 from an upper portion of said electrode means, as viewed in FIG. 1, to a lower portion thereof.
  • the terminology upper portion" and lower portion, as applied to electrode means 10, is used merely for convenience in describing the apparatus of FIG. 1 and should not be interpreted as limiting the configuration ,of the illustrated apparatus to pre-established vertical or horizontal planes. It is of course recognized that if donor member 20 is of an endless belt configuration the electrode means 10 may lie in a plane parallel to the surface of said donor member.
  • the electrode means 10 is adapted to produce an electrostatic field between the electrode means 10 and the surface 201 of donor member 20.
  • the electrostatic field is characterized by a uniformly varying magnitude from the upper portion of electrode means 10 to the lower portion thereof.
  • the direction of the electrostatic field is reversible over the illustrated dimension of the electrode means 10. Accordingly, a first portion 120 of said electrostatic field may emanate from the electrode means 10 toward surface 201 of donor member 20; and a second portion 121 of said electrostatic field may emanate from the surface 201 toward the electrode means 10.
  • the electrode means 10 may be comprised of conductive material having a relatively high resistance. Accordingly electrode means 10 may be comprised of glass, or ceramic material having a resistivity on the order of 10" ohm-centimeters. Alternatively, the electrode means 10 may comprise glass or ceramic material having a resistivity on the order of 10" ohm-centimeters and include thin layers of metal, carbon or conductive plasticcoated thereon. If desired the electrode means 10 may comprise a grid of fine parallel wires.
  • the relatively high resistivity of the electrode means is preferred so that a smoothly varying potential may be obtained on the surface thereof thereby inducing the aforementioned uniformly varying electrostatic field, and significant heat dissipation does not occur. Consequently, the electrode means 10 is divided into discrete portions represented as 101, 102, 103, 104,
  • a dc. voltage source 11 is connected to a voltage divider network comprised of series connected resistances 111, 112, 114, 115 and 116 whereby said selected d.c. potentials are produced by respective resistances. Accordingly, the junction between the d.c. voltage source 11 and resistance 111 is coupled to portion 101' of electrode means 10. Similarly, the junction between resistances 111 and 112 is coupled to portion 102. In a like manner the junction between resistances 112 and 114 is coupled to portion 103.
  • the junction between resistances 1 14 and 1 15 is coupled to portion 104.
  • the junction be tween resistances 115 and 116 is coupled to portion and the junction between resistance 116 and the dc. voltage source 11 is coupled to portion 106.
  • the dc. voltage source 11 may be comprised of two oppositely poled d.c. supplies.
  • one of the discrete portions of electrode means 10 may be coupled to the reference potential supplied to the donor member 20.
  • FIG. 1 illustrates that portion 103 is supplied with the aforementioned reference potential by applying a ground potential to the junction 113 between resistances 112 and 114.
  • the relative potential of portion 101 is greater than the relative potential at the surface 201 of donor member 20.
  • the potential of portion 102 is less than the potential of portion 101 but greater than the potential at the surface 201.
  • portion 103 is supplied with a potential equal to the potential at surface 201.
  • the potential at portion 104 is less than the potential at the surface 201 and the potential at portion 105 is less than the potential at portion 104.
  • the potential at portion 106 is less than that at portion 105.
  • the selected potentials applied to the discrete portions 101 106 of electrode means 10 may be produced by other conventional means such as a plurality of Zener diodes connected to a common source of voltage, or a plurality of individual d.c. voltage supplies, or the like.
  • Electrode means 10 adapted to produce the aforementioned uniformly varying electrostatic field may comprise a unitary structure having a resistive cermet coated surface such that a uniformly varying voltage potential is provided along the surface of said electrode means 10 from the upper portion thereof to the lower portion thereof in accordance with a dc. voltage applied thereto.
  • the electrophotographic developer particles 124 deposited on the surface 201 of donor member 20 may be supplied by a source of developer material 12.
  • Source of developer material 12 is adapted to be compatible with conventional xerographic developing techniques. Accordingly, if electrophotographic developer particles are to be cascaded across the surface 201 the source of developer material 12 may comprise a housing filled with a quantity of two-component developer material.
  • developer material consists of a pigmented resinous powder known as toner particles and coarse granular material known as carrier particles.
  • the carrier particles may comprise glass, sand or plastic coated steel beads so situated in the triboelectric series that charges are imparted to the toner particles of a polarity opposite to the polarity of the electrostatic charges comprising the electrostatic latent image to be developed.
  • the toner particles are formed of a material which is nearer to the negative end of the triboelectric series then the material comprising the carrier particles. Consequently, the toner particles adhere to the carrier particles.
  • the twocomponent developer material is adapted to drop from the housing 12 and to cascade over the surface 201 under the action of gravity. A sump, not shown, may be provided to recover the carrier particles and those toner particles not deposited on the surface 201.
  • donor member 20 and photoconductive plate 30 admit of a rotatable drum configuration.
  • the donor member 20 or the photoconductive plate 30 or both may be an endless belt, a movable rectangular member or the like.
  • the developer particles 124 on the surface 201 are selectively transferred to the surface 301 in conformity with the electrostatic charges 303 distributed on surface 301 to thereby develop the electrostatic latent image. This transfer of developer particles occurs because of the electrostatic forces exerted on said particles by the electrostatic charges 303.
  • the angular velocity of donor member 20 may be slightly greater than the angular velocity of the photoconductive plate 30.
  • the donor member and the photoconductive plate rotate in synchronism. It is recognized that the electrostatic forces exerted on developer particles 124 by the areas of surface 301 wherein electrostatic charges have been dissipated are not adequate to remove the developer particles from the surface 201. Consequently, some developer particles 123 adhere to the surface 201 and must be removed to enable a unifonn coating of developer particles to be deposited on surface 201.
  • a uniformly varying d.c. potential is provided along the surface of electrode means 10 in response to the voltages supplied thereto.
  • the dc. potential varies from a maximum of a positive polarity at portion 101 to a maximum of negative polarity at portion 106. Since the electrode means 10is comprised of resistive material the dc. potential provided along the surface thereof varies smoothly so that high electrostatic fields are not created across adjacent portions. It is noted however, that the potential difference between the portion 101 of electrode means 10 and the surface 201 is relatively high so that the magnitude of the electro toward surface 201 is less than that of the electrostatic field 120 in response to the decreased potential difference between the portion 102 and the surface 201.
  • the voltage applied to portion 103 is substantially equal to the reference potential at the surface 201 a neglible electrostatic field is produced therebetween.
  • the d.c. voltages applied to portions 104, 105 and 106 are effective to produce an electrostatic field emanating from the surface 20] toward the electrode means 10 of uniformly increasing magnitude.
  • the electrostatic field 121 exhibits a maximum value in the direction shown. It is now readily apparent that a uniformly varying potential is provided along the surface of the electrode means 10 whereby a unifomrly varying electrostatic field is established transversely of said electrode means 10 and the surface 201 of donor member 20.
  • the surface 201 of the donor member 20 is rotated past the electrode means 10 by conventional driving means, such as a motor, not shown, whereby the surface 201 successively traverses the uniformly varying electrostatic field.
  • Developer material is introduced at the upper portion of the electrode means 10.
  • the source of developer material 12 comprises a housing for two-component developer.
  • the two-component developer which is comprised of carrier particles having toner particles adhering thereto, is cascaded over the surface 201 under the action of gravity.
  • the flowing two-component developer collides with residual developer particles 123 adhering to the surface 201 of donor member 20, thereby dislodging said developer particles.
  • the electrostatic field exerts corresponding electrostatic forces on the dislodged developer particles 123 sufficient to sweep said dislodged developer particles into the flowing developer stream and to direct the particles toward the electrode means 10. Although some dislodged developer particles will be deposited on the surface of the electrode means 10, only a relatively thin layer will accumulate because of the action of the flowing developing stream. Thus it is seen that the surface 201 of donor member 20 is electrostatically cleaned as it is translated past a first portion of the electrode means 10.
  • the electrostatic forces exerted on the developer particles adhering to the carrier particles of the twocomponent developer inhibit the transfer of such developer particles to the surface 201 as the two-component developer falls through the unifomily varying electrostatic field.
  • developer particles that are jarred loose from their associated carrier particles while cascading across surface 201 are urged toward the electrode means 10 and therefore are not transferred to the surface 201.
  • the unassociated developer particles and the dislodged developer particles 123 pass through that portion of the electrostatic field that is uniformly increasing in magnitude and emanates from the surface 201 toward the electrode means 10, the resulting electrostatic forces are sufficient to deposit a uniform coating of developer particles 124 onto said surface.
  • the uniformly increasing electrostatic field tends to insure a uniform deposit of developer particles onto the surface 201 of donor member 20.
  • FIG. 2 Another embodiment of the present invention is illustrated in FIG. 2 which comprises photoconductive plate 30 and electrode means 40.
  • the photoconductive plate 30 of FIG. 2 is identical to the aforedescribed photoconductive plate 30 of FIG. 1 and is herein illustrated in rectangular configuration.
  • Said photoconductive plate 30 is adapted to be translated with respect to electrode means 40 in the direction indicated by the arrow B. It is understood the electrode means 40 may be translated in the opposite direction.
  • Electrode means 40 is similar to aforedescribed electrode means 10 and may be formed from highly resistive material. As illustrated, the electrode means 40 is divided into discrete portions 401 405 wherein adjacent portions are separated by highly insulating material 406. Each of said discrete portions is provided with a selected d.c. voltage which may be supplied thereto from a plurality of d.c. voltage sources, or as indicated in the drawings, by a conventional voltage divider network connected to a d.c. supply 1 l. The voltage divider network is comprised of series connected resistances 212 215. Each junction formed by the series connection of resistances is coupled to one of the discrete portions 401 405 of the electrode means 40.
  • An additional resistance 216 is connected between resistance 215 and a reference potential such as ground potential such that the voltage supplied to portion 405 of electrode means 40 is maintained above said reference potential.
  • the electrode means 40 is disposed in spaced registration from the surface of photoconductive plate 30 and is substantially coextensive with at least a portion of said photoconductive plate. Accordingly, the electrode means 40 is parallel to the photoconductive plate 30 and admits of a dimensional characteristic normal to the plane of the paper of the drawings herein at least equal to the corresponding dimensional characteristic of the photoconductive plate 30. It should now be readily apparent from the description set forth hereinabove with respect to FIG. 1 that the electrode means 40 is adapted to have a uniformly varying potential provided along the surface thereof. If the d.c.
  • voltage supply 11 is assumed to be a conventional d.c. battery having a positive terminal coupled to portion 401 of the electrode means 40 it is understood that the potential provided along the surface of the electrode means 40 varies uniformly from a maximum value of. approximately l,000 volts to a minimum value of approximately 150 volts in the direction of translation B of the photoconductive plate 30. Therefore an electrostatic field of uniformly varying magnitude is capable of being produced transversely of the electrode means 40 and the surface of photoconductive plate 30.
  • the apparatus illustrated in FIG. 2 is particularly adapted to treat the surface of the photoconductive plate 30 whereby'an original electrostatic latent image thereon may be repeatedly developed and a plurality of copies of graphic information corresponding to said electrostatic latent image may beproduced. ln operation the developed image may be transferred to a support surface in a manner resulting in negligible distortion of the electrostatic charge pattern as described in US. Pat. No. 3,244,083 which issued to R..W. Gundlach and assigned to Xerox Corporation. Although photoconductive plate 30 may be translated to a conventional cleaning station, such as the type described in US. Pat. No. 2,751,616 which issued to M. l. Turner Jr., et al.
  • the d.c. voltage supplied to portion 401 of electrode means 40 is of sufficient magnitude, such as 1,000 volts, the potential induced on the surface of said portion 401 exceeds the potential at the surface of photoconductive plate 30 attributable to the distribution of the electrostatic charges 303. Consequently, electrostatic forces are exerted on thedislodged toner particles 423 to urge said toner particles toward the surface of the electrode means 40.
  • the magnitude of the electrostatic field produced in the vicinity of the portion 402 of electrode means 40 is slightly less than the magnitude of the electrostatic field produced in the vicinity of portion 401. However, the former may still be sufficient to urge toner particles toward the surface of the electrode means 40. It is recalled that uniformly varytrode means 40, such as portions 401 and 402, which result in the deposition of toner particles on the surface of the electrode means.
  • the additional toner particles 422 of the twocomponent developer material introduced into the space between the electrode means 40 and the surface of the photoconductive plate 30 in the manner previously described with respect to FIG. 1, will likewise. be urged toward the electrode means 40. It is recognized that since a uniformly decreasing potential is provided along the surface of the electrode means 40 there exists a position at the surface of the electrode means whereat the potential is less than the potential of the distributed electrostatic charges 303. At this position the electrostatic forces exerted on the toner particles 422 by the selectively distributed electrostatic charges 303 exceed the electrostatic forces exerted on said toner particles by the electrode means 40.
  • the toner particles are urged toward and deposited on the surface of the photoconductive plate 30 in conformity with the distribution of the electrostatic charges 303, thereby forming a developed image 304.
  • the electrostatic forces exerted on the toner particles 422 by the electrostatic charges 303 increase because. the potential provided along the surface of the electrode means 40 decreases.
  • the magnitude of the potential provided along the surface of the portion 405 although a minimum value, exceeds the potential at the surface of photoconductive plate 30 in the non-image areas to thereby inhibit the deposit of toner particles 422 on said nonimage areas.
  • the potential provided at portion 405 will be approximately 150 volts if the background potential is equal to volts. It should therefore be understood that the major change in the uniformly decreasing potential provided along the surface of electrode means 40 occurs between portions 402 and 404 thereof.
  • FIG. 3 A further embodiment of the present invention is illustrated in FIG. 3 which comprises electrode means 50 and photoconductive plate 30.
  • the apparatus illustrated in FIG. 3 is adapted to develop an electrostatic latent image comprised of electrostatic charges 303 selectively distributed on the surface of the photoconductive plate 30, which photoconductive plate has previously been cleaned by conventional means. Accordingly, the removal of toner particles that might adhere to the surface of the photoconductive plate 30 is merely incidental to the principal function of development as performed by the electrode means 50.
  • the photoconductive plate 30 is illustrated in drum configuration, however it is apparent that said photoconductive plate may comprise a rectangular member as illustrated in FIG. 2 or an endless belt.
  • the electrode means 50 is similar to aforedescribed electrode means and is disposed in spaced registration from the surface of the photoconductive plate 30 and is substantially coextensive therewith for at least a portion of said photoconductive plate.
  • the longitudinal dimension of the electrode means 50 is at least equal to the longitudinal dimension of the photoconductive plate 30.
  • Discrete portions 501 506 of the electrode means 50 are adapted to be supplied with selected d.c. potentials whereby a uniformly varying potential is induced across the surface of said electrode means 50. Accordingly, a singular voltage supply may be coupled to each of said discrete portions 501 506.
  • a single voltage source 11 is connected to a conventional voltage divider network comprised of series connected resistances 311 through 315.
  • the voltage produced at each junction formed by the series connection of resistances is supplied to a corresponding portion 501 506 of electrode means 50.
  • the electrode means 50 is adapted to produce an electrostatic field transversely of the electrode means 50 and the surface of the photoconductive plate 30.
  • the magnitude of said electrostatic field exhibits a decreasing characteristic in the direction of rotation B of the photoconductive plate 30.
  • a source of developer material 12 identical to the aforedescribed source of developer material illustrated in FIG. 1 is disposed to introduce toner particles 122 into the space between the electrode means 50 and the surface of the photoconductive plate 30.
  • the photoconductive plate 30 is driven by conventional driving means, such as a motor, not shown, to transport an electrostatic latent image comprised of electrostatic charges 303 selectively distributed on the surface of the photoconductive plate past electrode means 50.
  • driving means such as a motor, not shown
  • the distribution of the electrostatic charges 303 corresponds to a light image that has been projected onto the surface of the photoconductive plate 30.
  • the non-image areas on the surface of the photoconductive plate 30 correspond to the highlights of the projected image and may have a voltage potential not much less than the reference potential suchas the bias potential that is applied to the conductive backing of the photoconductive plate 30. Accordingly, the non-image areas may exhibit a voltage potential of approximately 100 volts.
  • the portion 506 may be supplied with a negative dc. voltage thereby resulting in a deposit of toner particles on non-image areas. It is recognized that a smoothly varying d.c. potential is induced along the surface of the electrode means 50 thereby preventing high electrostatic fields from being established across adjacent portions of the electrode means 50 which could result in the deposition of toner particles on the surface of the electrode means.
  • the present invention is effective to remove toner particles adhering to a surface and to subsequently deposit a uniform layer of toner particles on said surface.
  • electrostatic charges have been described as exhibiting positive polarity and the toner particles have been described as exhibiting negative polarity, it should be readily apparent that the respective polarities may be interchanged. It is merely required that electrostatic attraction be obtained between the toner particles and the selectively distributed electrostatic charges.
  • development of the electrostatic latent image on photoconductive plate 30 may be photographically positive or negative depending upon the contemplated application of the present invention.
  • the resistive electrode means described herein has been provided with discrete portions so that a smoothly varying potential may be obtained on the surface thereof.
  • the electrode means may comprise a unitary structure including a cermet resistive coated surface.
  • the precise magnitude of the uniformly varying electrostatic field produced by the electrode means is suitable to induce electrostatic forces that are sufficient to clean toner particles from a surface and to uniformly deposit toner particles on said surface.
  • Apparatus for developing an electrostatic latent image comprised of electrostatic charges selectively distributed on a photoconductive plate comprising:
  • translatable surface adapted to receive charged toner particles
  • said electrode means including a cermet resistive coated surface
  • said inducing means comprising a constant voltage supply coupled to opposite ends of said electrode means for applying the voltage supplied by said constant voltage supply across said electrode means.
  • an apparatus for cleaning and applying toner particles to a surface comprising:
  • image comprised of electrostatic charges selectively distributed on a photoconductive plate, comprising:
  • Apparatus for developing an electrostatic latent image comprised of electrostatic charges selectively distributed on a photoconductive plate comprising:
  • translatable surface located adjacent said plate and adapted to receive charged toner particles

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Dry Development In Electrophotography (AREA)
  • Developing For Electrophotography (AREA)
  • Cleaning In Electrography (AREA)
US00180426A 1971-09-14 1971-09-14 Image developing apparatus Expired - Lifetime US3818864A (en)

Priority Applications (7)

Application Number Priority Date Filing Date Title
US00180426A US3818864A (en) 1971-09-14 1971-09-14 Image developing apparatus
CA147,737A CA980181A (en) 1971-09-14 1972-07-24 Image developing techniques
DE2239207A DE2239207A1 (de) 1971-09-14 1972-08-09 Verfahren und vorrichtung zur xerographischen vervielfaeltigung mittels unterschiedlich vorgespannter elektroden
NL7212332A NL7212332A (xx) 1971-09-14 1972-09-11
GB4232272A GB1406292A (en) 1971-09-14 1972-09-12 Image developint techniques
JP47092213A JPS4838735A (xx) 1971-09-14 1972-09-13
US452152A US3908037A (en) 1971-09-14 1974-03-18 Image developing techniques

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US00180426A US3818864A (en) 1971-09-14 1971-09-14 Image developing apparatus

Publications (1)

Publication Number Publication Date
US3818864A true US3818864A (en) 1974-06-25

Family

ID=22660418

Family Applications (1)

Application Number Title Priority Date Filing Date
US00180426A Expired - Lifetime US3818864A (en) 1971-09-14 1971-09-14 Image developing apparatus

Country Status (6)

Country Link
US (1) US3818864A (xx)
JP (1) JPS4838735A (xx)
CA (1) CA980181A (xx)
DE (1) DE2239207A1 (xx)
GB (1) GB1406292A (xx)
NL (1) NL7212332A (xx)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3908037A (en) * 1971-09-14 1975-09-23 Xerox Corp Image developing techniques
US3911865A (en) * 1973-03-30 1975-10-14 Xerox Corp Toner pickoff apparatus
US3911861A (en) * 1973-12-03 1975-10-14 Addressograph Multigraph Programmable toner concentration control
US3996892A (en) * 1975-02-24 1976-12-14 Xerox Corporation Spatially programmable electrode-type roll for electrostatographic processors and the like
US4052127A (en) * 1973-01-24 1977-10-04 Ricoh Co., Ltd. Developing system
USRE31371E (en) * 1973-01-24 1983-09-06 Ricoh Co., Ltd. Developing system
US4431296A (en) * 1981-04-27 1984-02-14 Konishiroku Photo Industry Co., Ltd. Developing method and apparatus therefor
US4558941A (en) * 1983-03-31 1985-12-17 Takefumi Nosaki Developing apparatus
US5032485A (en) * 1978-07-28 1991-07-16 Canon Kabushiki Kaisha Developing method for one-component developer
US5096798A (en) * 1978-07-28 1992-03-17 Canon Kabushiki Kaisha Developing method for one-component developer
US5194359A (en) * 1978-07-28 1993-03-16 Canon Kabushiki Kaisha Developing method for one component developer

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5512962A (en) * 1978-07-14 1980-01-29 Ricoh Co Ltd Electrophotographic copy
US4535261A (en) * 1981-06-03 1985-08-13 Ckd Controls Limited Smallsize motor with reduction gear and clutch mechanism
JPS59181372A (ja) * 1983-03-31 1984-10-15 Toshiba Corp 現像装置

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3147147A (en) * 1961-06-05 1964-09-01 Xerox Corp Xerographic developing apparatus and electrode
US3328193A (en) * 1962-10-02 1967-06-27 Australia Res Lab Method of and means for the transfer of images
US3411482A (en) * 1967-01-30 1968-11-19 Varian Associates Electrographic toner development employing a clean-up electrode structure for removing unwanted background
US3412710A (en) * 1966-10-11 1968-11-26 Xerox Corp Cleanup electrode
US3416494A (en) * 1967-12-26 1968-12-17 Xerox Corp Xerographic development electrode
US3601092A (en) * 1969-02-28 1971-08-24 Ricoh Kk Developing device for wet process electrophotography
US3638610A (en) * 1969-07-03 1972-02-01 Xerox Corp Development apparatus
US3696785A (en) * 1970-12-18 1972-10-10 Xerox Corp Development apparatus

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3147147A (en) * 1961-06-05 1964-09-01 Xerox Corp Xerographic developing apparatus and electrode
US3328193A (en) * 1962-10-02 1967-06-27 Australia Res Lab Method of and means for the transfer of images
US3412710A (en) * 1966-10-11 1968-11-26 Xerox Corp Cleanup electrode
US3411482A (en) * 1967-01-30 1968-11-19 Varian Associates Electrographic toner development employing a clean-up electrode structure for removing unwanted background
US3416494A (en) * 1967-12-26 1968-12-17 Xerox Corp Xerographic development electrode
US3601092A (en) * 1969-02-28 1971-08-24 Ricoh Kk Developing device for wet process electrophotography
US3638610A (en) * 1969-07-03 1972-02-01 Xerox Corp Development apparatus
US3696785A (en) * 1970-12-18 1972-10-10 Xerox Corp Development apparatus

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3908037A (en) * 1971-09-14 1975-09-23 Xerox Corp Image developing techniques
US4052127A (en) * 1973-01-24 1977-10-04 Ricoh Co., Ltd. Developing system
USRE31371E (en) * 1973-01-24 1983-09-06 Ricoh Co., Ltd. Developing system
US3911865A (en) * 1973-03-30 1975-10-14 Xerox Corp Toner pickoff apparatus
US3911861A (en) * 1973-12-03 1975-10-14 Addressograph Multigraph Programmable toner concentration control
US3996892A (en) * 1975-02-24 1976-12-14 Xerox Corporation Spatially programmable electrode-type roll for electrostatographic processors and the like
US5032485A (en) * 1978-07-28 1991-07-16 Canon Kabushiki Kaisha Developing method for one-component developer
US5044310A (en) * 1978-07-28 1991-09-03 Canon Kabushiki Kaisha Developing apparatus for non-magnetic developer
US5096798A (en) * 1978-07-28 1992-03-17 Canon Kabushiki Kaisha Developing method for one-component developer
US5194359A (en) * 1978-07-28 1993-03-16 Canon Kabushiki Kaisha Developing method for one component developer
US4431296A (en) * 1981-04-27 1984-02-14 Konishiroku Photo Industry Co., Ltd. Developing method and apparatus therefor
US4558941A (en) * 1983-03-31 1985-12-17 Takefumi Nosaki Developing apparatus

Also Published As

Publication number Publication date
JPS4838735A (xx) 1973-06-07
DE2239207A1 (de) 1973-03-22
NL7212332A (xx) 1973-03-16
GB1406292A (en) 1975-09-17
CA980181A (en) 1975-12-23

Similar Documents

Publication Publication Date Title
US4121931A (en) Electrographic development process
US3909258A (en) Electrographic development process
US3893418A (en) Xerographic developing apparatus
US5255057A (en) Gray scale monocomponent nonmagnetic development system
US4102305A (en) Development system with electrical field generating means
US3818864A (en) Image developing apparatus
US3759222A (en) Microfield donor with continuously reversing microfields
US2911330A (en) Magnetic brush cleaning
US3166432A (en) Image development
US3124457A (en) Charge
US4165393A (en) Magnetic brush developing process for electrostatic images
US3599605A (en) Self-biasing development electrode for electrophotography
US3739748A (en) Donor for touchdown development
GB2055695A (en) Imaging surface discharge and cleaning apparatus for electrophotographic copier
US4349270A (en) Developer removing device for copying apparatus
US4289837A (en) Development method and apparatus
US3589895A (en) Electrographic developing method suited for transfer electrophotography without cleaning
US4342822A (en) Method for image development using electric bias
US3542579A (en) Electrostatic image development
US3973843A (en) Electrostatographic imaging apparatus
US3719169A (en) Plural electrode development apparatus
US3908037A (en) Image developing techniques
US3444369A (en) Method and apparatus for selective corona treatment of toner particles
US3503776A (en) Xerographic development
US3807997A (en) Plural electrode development methods for latent electrostatic images