US3914460A - Development utilizing electric fields - Google Patents

Development utilizing electric fields Download PDF

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Publication number
US3914460A
US3914460A US322254A US32225473A US3914460A US 3914460 A US3914460 A US 3914460A US 322254 A US322254 A US 322254A US 32225473 A US32225473 A US 32225473A US 3914460 A US3914460 A US 3914460A
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US
United States
Prior art keywords
toner
development zone
donor member
web
development
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
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US322254A
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English (en)
Inventor
John Maksymiak
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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Filing date
Publication date
Application filed by Xerox Corp filed Critical Xerox Corp
Priority to US322254A priority Critical patent/US3914460A/en
Priority to CA189,294A priority patent/CA1027427A/en
Priority to DE2400716A priority patent/DE2400716A1/de
Priority to JP49005857A priority patent/JPS5815790B2/ja
Priority to NL7400317A priority patent/NL7400317A/xx
Application granted granted Critical
Publication of US3914460A publication Critical patent/US3914460A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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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
    • G03G15/0806—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
    • G03G15/081—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 handling means after the supply and before the regulating, e.g. means for preventing developer blocking

Definitions

  • a number of measures can be taken to improve the operation of a donor member used in this development mode. For instance, if the toner layer is spaced from the surface being developed so that it does not touch it, there is a less likelihood that toner supplied by the donor member will deposit in the non-image areas. This is because the toner on the donor member does not touch the surface and the non-image areas will not attract the toner.
  • the density of the final copy can be further controlled by selecting the gap distance between the donor member and surface. Since the strength of the electrostatic fields terminating on the surface being developed decreases as a function of the distance from that surface, the gap distance between the toner layer on the donor member and the surface is very critical. Even at relatively modest gap distances it has been found that less than complete development takes place. Development has been enhanced by placing a potential on the donor member itself which tends to aid the toner in overcoming the forces attracting it to the donor member, but, when such a potential is applied, the toner tends to be driven to the surface in random fashion and deposited in non-image areas. This condition is known as background development and degrades the quality of the final copy.
  • the donor member is a three-layer structure including a conductive base, a dielectric layer over the base and a conductive grid on top of the dielectric layer.
  • a potential opposite in polarity to a charge on the toner particles is placed on the conductive base thereby attracting toner particles to the surface areas between the grid elements. Then, when development is to take place, the potential is removed from the conductive base, or, alternatively, a potential of the same polarity as the charge on the toner particles is placed on the conductive base. Both create a condition which tends to blow the toner off the donor member in a cloud and into contact with the surface being developed.
  • the overlying conductive grid serves generally to breakup the field lines emanating from the conductive backing of the donor during loading and blow-off so as to create the characteristically strong fringe fields which exist over a surface having variable electrical potential. Because the toner is in the form of a cloud, the possibility of random deposition of toner, particularly in nonimage areas, is increased.
  • a third type of donor member also involves creating fringe fields and this is described in US. Pat. No. 3,203,394.
  • the donor member has a conductive base with a poorly insulating layer thereon and then a pattern of good insulating posts as a top layer.
  • This donor configuration is used basically to make it easier to load toner on the periphery of the donor prior to bringing it into the development zone.
  • the structure is electrostatically charged and then brought into the loading area. Between the charging station and the loading station, the poorly insulating layer loses its charge so that the fringe fields are created on the surface between the insulating posts and the poorly insulating intermediate layer.
  • toner is placed only between the insulating posts thereby creating a discontinuous layer of toner on the donor. This is not totally desirable because it limits the amount of toner that can be brought to the development zone.
  • the position of the piles of toner on the donor relative to the image areas on the surface may not always be in synchronism. If this is the case, certain of the image areas on the surface would not be fully developed for lack of toner.
  • the present invention relates to a development method and apparatus which imposes electrical fields on the toner layer and donor member within the development zone so that toner is made readily available to image areas of the surface being developed yet is not randomly deposited on the non-image areas.
  • the donor member takes the form of an endless rotatable belt passing through a toner loading area and then adjacent the surface being developed. Toner loaded onto the belt is subjected to an electrical field which activates the toner on the donor member as it passes through the development zone. Those toner particles are attracted to image areas of the surface during activation follow the field back to the donor surface where they are removed from the development zone.
  • toner In the development zone, although toner is loosened and- /or separated from the donor due to the electrical field, it continues to be under the control of the electrical field. This arrangement prevents random deposition of toner in the non-image areas thereby reducing background. This arrangement also allows greater flexibility in establishing gap distance between donor and surface without the usual drop off in development quality.
  • the present invention relates to a method and apparatus for developing electrostatic latent images by bringing a toner-laden donor member adjacent a surface bearing a latent image and thereupon transferring the toner to the surface in conformance with the image.
  • the toner is exposed to an electric field in the development zone which activates it as it passes into the development zone thereby making it readily-attractable by the electrostatic image on the surface.
  • the electric field is shaped so that the activated toner which is not attracted to image areas of the surface is redeposited on the donor member as it leaves the development zone.
  • the toner layer on the donor is separated from the surface by a gap and the electric field is sufficient to reduce the attraction of the toner to the donor or, in the alternative, separate the toner from the donor.
  • the toner layer can be in contact with the surface being developed and the affect of the field is to control the action of the toner in the development zone so that little or no toner is deposited in non-image areas of the surface.
  • FIG. 1 is a schematic illustration of the invention in a xerographic system.
  • FIG. 2 is a detailed view of an embodiment of the invention.
  • FIGS. 3 and 4 are detailed views of the electric field in the development zone.
  • FIG. 5 is a detailed view of another embodiment of .the invention.
  • FIG. 6 is another detailed view of the electric field in the invention.
  • the present invention can be adapted to any reproduction apparatus wherein toner is used to develop an electrostatic latent image.
  • toner is used to develop an electrostatic latent image.
  • the invention will be described principally within the environment of a xerographic reproduction apparatus.
  • FIG. 1 there is shown a schematic view of a continuous xerographic copier having a photosensitive member in the shape of a drum 1] on which a latent electrostatic image of the information to be reproduced is formed.
  • the rotatable drum 1] is driven about shaft 2 by any suitable means so that the drum surface passes through stations AE in a continuous manner.
  • the peripheral surface of the drum is covered by an electrically conductive material which, in turn, is covered on its outer surface with a photoconductive material such as vitreous selenium.
  • the drum has five processing stations located about its periphery which carry out the steps of the xerographic process. These stations include charging station A, exposing station B, developing station C, transfer station D, and cleaning station E.
  • An electrostatic latent image is formed on the drum 1] by passing its surface through charging station A and exposure station B.
  • Charging station A can include any suitable means for placing a uniform charge on the photoconductive layer such as a corona charging device.
  • Exposing station B can include any suitable device which projects and focuses a light pattern on the drum conforming to the image to be reproduced by the xerographic system. The light image projected onto the charged photoconductive layer of the drum is synchronized with the movement of the drum and causes selective charge dissipation on elemental areas of the drum to form an electrostatic latent image thereon.
  • the drum After the formation of the electrostatic latent image by passing the drum through stations A and B, the drum carries the latent image through developing station C.
  • a suitable developer material hereinafter referred to a toner
  • a pigmented resinous electroscopic powder is deposited on the drum in imagewise configuration according to the teachings of this invention.
  • the drum carries the toner image through transfer station D where the toner image is transferred from the drum surface to any suitable support material such as a sheet of paper, continuous web, or any other form of substrate which can be used to receive toner images.
  • Transfer of the toner image onto the copy sheet is carried out in any suitable manner such as by electrostatically attracting the toner image from the drum onto a sheet of paper with a corona discharge device.
  • a fixing device or other suitable processing station fixes the toner image. Any suitable fixing device which makes the toner permanent on the copy sheet is suitable.
  • Station E can include any suitable cleaning device, such as fur brush, which contacts the photoconductive surface of the drum.
  • the cleaning station is utilized to remove any residue toner particles from the photosensitive surface FIG. 1, toner 18 picked up'from reservoir 17 by donor member 12 is brought adjacent the drum 11 at station C.
  • the donor member is shown in the form of an endless belt and rotates in the clockwise direction. The toner particles adhere to the belt and pass around roller 13 and field producing device 3 where they are transferred to the drum to develop the image thereon.
  • the toner can be sprayed electrostatically by corona charging device 16 to assure that all toner particles have the same charge.
  • FIG. 2 provides a more detailed view of the donor member.
  • the belt 12 may be insulating and may be made of a material which when rubbed with toner produces a triboelectric action making the toner attractive to it.
  • loading of the belt may be carried out without regard to its triboelectric relationship to the toner. In such a case, loading may be aided by grounding roller 13 and vibrating reservoir 17 by any suitable means.
  • the donor member could be made of a material having a suitable triboelectric relationship to toner particles so that toner could be cascaded along with carrier beads over the surface of the donor, the toner adhering to the donor member in traditional cascade development fashion.
  • Another known way of placing toner on a donor member would be to expose the member to a charged cloud of toner particles which would be attracted to the donor member surface.
  • the toner layer 19 may optionally be sprayed with a uniform charge such as by corona device 16. This provides good attraction between the toner and image areas of the drum during development.
  • the charge sprayed on the toner layer will be selected based on the development system used. For instance, it is common to charge a xerographic to a high positive potential and then expose the non-image areas to light which reduces the potential on those portions of the drum. In this case, if the high potential areas are to be developed, the toner would be charged negatively. However, if the low potential areas were to be developed, the toner would be charged positively.
  • Field producing apparatus 3 includes ground plate and biased plate 14.
  • Ground plate 15 is placed behind belt 12 and forms the surface upon which belt 12 rides. Plate 15 may extend from the development zone through the charging area as shown.
  • the other portion of field-producing apparatus 3 is bias plate 14 which can also form the surface upon which the belt rides as it exits the development zone. Plates l4 and 15 are not in electrical contact because it is the combination of these two members which creates the electrical field through the development zone to be described in more detail in FIGS. 3 and 4.
  • FIG. 1 there is provided an air space 30 between members 14 and 15 for electric insulation while in FIG. 2 insulating plate 31 provides proper insulation between the plates.
  • the potential applied to plate 14 will depend on the charge of the toner particles and is opposite thereto in polarity. As described in FIG. 2, if a negative charge is sprayed on to the toner layer by corona device 16, the bias on plate 14 will be positive. On the other hand, if the positive toner is used, plate 14 will be biased to a negative polarity. The combination of biased plate 14 and grounded plate 15 generate an electric field between the two plates and toner in the development zone will be attracted towards plate 14.
  • FIGS. 3 and 4 show a more detailed view of the development zone. Due to the fact that member 15 is grounded and member 14 is at a positive potential, a fringe field effect will be created between these two members in the vicinity of the development zone. This electric field extends through donor member 12 and toner layer 19. The lines of force in the fringe field is indicated by broken lines passing between members 14 and 15.
  • the purpose of the field is to activate the toner while it is in the development zone so that it is readily attractable by the electrostatic image on the drum.
  • activation includes, in the alternative, reducing the forces that attract the toner to the donor or reversing the forces to separate the toner from the donor.
  • the electric field can be of such force as to actually dislodge and separate toner particles from the belt in the development zone.
  • the attraction of the toner to the donor is merely lessened or reduced to zero so that the image areas of the drum can attract it to the drum.
  • the pluses indicate the image areas of the drum, the balance of the drum being the non-image areas.
  • Toner which is activated by following the electric field created by plates 14 and 15 is free to be attracted to the image areas. However, since an image area is not adjacent the donor at the moment shown, the activated toner does not cross the gap to the surface being developed. Instead, the toner particles complete their journey in conformance with the electric field generated by plates 14 and 15 and are reattracted onto the donor memberdue to the electrical field produced by member 14.
  • FIG. 4 there is shown the condition when an image area is more clearly in the development zone and is available for the receipt of toner from the donor member.
  • the fields created by the image areas of the drum attract activated toner as needed across the gap and onto the drum surface to develop the image. Any activated toner not so attracted completes its journey through the development zone in conformance with the electric field created by the donor member and is redeposited onto the surface of member 15.
  • the present invention In addition to preventing the random deposition of toner in background areas, the present invention also allows a good deal of flexibility in the spacing of the donor member from the surface being developed.
  • One problem in previously known apparatus has been that it was not alwayspossible to have sufficiently strong fields from the image areas of the drum to reliably remove toner from the donor member at larger gap distances.
  • gap spacing is not as critical and larger spacing is readily permitted. This is because the electric field which activates the toner frees the toner from its adhesion to the donor member, thereby reducing the electrostatic force required to attract toner to the drum.
  • FIG. discloses another embodiment of the invention.
  • an endless belt such as insulating belt 20 is supported and driven about rollers 21 and 22 in a counterclockwise manner.
  • the external surface of the belt picks up toner particles 7 from vibrating toner reservoir 26.
  • a grounded electrode 23 is placed over the hopper 26 and extends toward the development zone.
  • Toner particles 28 picked up by the belt are brought into the development zone of drum 29 by the moving belt.
  • Plate 23 which is electrically grounded is also electrically insulated from plate 25 by insulating material 24.
  • Plate 25 has a polarity opposite that of the toner particles.
  • the electric field generated in the development zone across plates 23 and 25 is similar to that described in conjunction with FIGS. 3 and 4.
  • activated toner particles which are following the electric field between plates 23 and 25 are free to be attracted to the image areas on drum 11. Any activated toner particles which are not attracted to the drum are deposited onto the belt as it exits the development zone, and are not left in an uncontrolled situation within the development zone.
  • the charge on the toner particles delivered by the donor member can be positive or negative depending upon the nature of the charge in the image areas.
  • the configuration of the donor member is not necessarily limited to an endless belt.
  • the donor could take to the shape of a roller or a continuous web.
  • the developing method and apparatus disclosed can be used as part of any larger reproduction apparatus where it is desired to develop an electrostatic latent image.
  • other electrostatographic imaging systems can utilize this process including other electrophotographic and electrography systems.
  • a method of developing an electrostatic latent image carried by a surface comprising the steps of:
  • the method according to claim 1 further including a preliminary step of charging the toner to a given polarity prior to its passing through the development zone.
  • a method of developing an electrostatic latent image carried by a surface as said surface movesthrough a development zone comprising the steps of:
  • toner subjecting the toner to an electric field shaped to reduce the attraction of the toner to the donor member as the toner enters the development zone whereby the toner is readily-attractable to the surface in conformance with the image thereon and to increase the attraction of the toner to the donor member as said donor member leaves the development zone whereby toner not attracted to said surface is removed from said development zone.
  • a method of developing an electrostatic latent ima'ge carried by a surface including the step of transporting toner to the development zone by a web; the improvement comprising the additional step of subjecting the toner and web to an electric field which activates the toner as it enters the development zone whereby the toner is readily-attractable to the surface in conformance with the image thereon and which reattracts the activated toner not attracted to the surface onto the web as it leaves the development zone.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Dry Development In Electrophotography (AREA)
  • Developing For Electrophotography (AREA)
US322254A 1973-01-09 1973-01-09 Development utilizing electric fields Expired - Lifetime US3914460A (en)

Priority Applications (5)

Application Number Priority Date Filing Date Title
US322254A US3914460A (en) 1973-01-09 1973-01-09 Development utilizing electric fields
CA189,294A CA1027427A (en) 1973-01-09 1974-01-02 Development utilizing electric fields
DE2400716A DE2400716A1 (de) 1973-01-09 1974-01-08 Verfahren und vorrichtung zum entwickeln einer latente elektrostatische bilder tragenden flaeche mit toner
JP49005857A JPS5815790B2 (ja) 1973-01-09 1974-01-09 静電写真現像装置
NL7400317A NL7400317A (enrdf_load_stackoverflow) 1973-01-09 1974-01-09

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US322254A US3914460A (en) 1973-01-09 1973-01-09 Development utilizing electric fields

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US3914460A true US3914460A (en) 1975-10-21

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US322254A Expired - Lifetime US3914460A (en) 1973-01-09 1973-01-09 Development utilizing electric fields

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US (1) US3914460A (enrdf_load_stackoverflow)
JP (1) JPS5815790B2 (enrdf_load_stackoverflow)
CA (1) CA1027427A (enrdf_load_stackoverflow)
DE (1) DE2400716A1 (enrdf_load_stackoverflow)
NL (1) NL7400317A (enrdf_load_stackoverflow)

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4067295A (en) * 1975-03-07 1978-01-10 Xerox Corporation Magnetic microfield donor system
US4195991A (en) * 1977-10-21 1980-04-01 James River Graphics Inc. Electrographic recording method of applying an electric field opposite the charge retaining layer
US4356245A (en) * 1977-09-10 1982-10-26 Canon Kabushiki Kaisha Method and apparatus for electrophotographic, image development with magnetic toner
US4386577A (en) * 1977-09-10 1983-06-07 Canon Kabushiki Kaisha Developing apparatus for electrostatic image
US4614419A (en) * 1984-09-20 1986-09-30 Xerox Corporation Pre-development inductive charging of developer material
US4666815A (en) * 1983-10-19 1987-05-19 Canon Kabushiki Kaisha Method for developing electrostatic latent image with non-magnetic toner
US4920381A (en) * 1989-01-03 1990-04-24 Eastman Kodak Company Toner container lift mechanism
US4978597A (en) * 1988-02-29 1990-12-18 Canon Kabushiki Kaisha Image forming method and image forming apparatus utilizing a toner-carrying member with spherical concavities
US5040004A (en) * 1989-12-18 1991-08-13 Xerox Corporation Belt donor for direct electrostatic printing
US5119147A (en) * 1990-12-24 1992-06-02 Xerox Corporation Selective coloring of bi-level latent electostatic images
US5247317A (en) * 1991-12-12 1993-09-21 Oce-Nederland B.V. Printing device with control of developer roller spacing
US5276488A (en) * 1992-08-31 1994-01-04 Xerox Corporation Donor belt and electrode structure supported behind the belt for developing electrostatic images with toner
EP0601786A3 (en) * 1992-12-07 1995-07-19 Xerox Corp Correct loading of a delivery roller for hybrid development.
US6023600A (en) * 1998-08-31 2000-02-08 Xerox Corporation Ion charging developement system
US6223013B1 (en) * 1998-12-14 2001-04-24 Xerox Corporation Wire-less hybrid scavengeless development system

Families Citing this family (10)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4292387A (en) * 1978-07-28 1981-09-29 Canon Kabushiki Kaisha Magnetic developing method under A.C. electrical bias and apparatus therefor
JPH0642081B2 (ja) * 1984-06-20 1994-06-01 株式会社東芝 現像剤
JPS621988A (ja) * 1985-06-27 1987-01-07 積水化学工業株式会社 窓枠
JPS621987A (ja) * 1985-06-27 1987-01-07 積水化学工業株式会社 窓枠
JP2010039390A (ja) * 2008-08-07 2010-02-18 Ricoh Co Ltd 現像装置および画像形成装置
JP5397734B2 (ja) * 2008-09-08 2014-01-22 株式会社リコー 現像装置および画像形成装置
JP4618373B2 (ja) * 2008-12-22 2011-01-26 ブラザー工業株式会社 現像剤供給装置
JP4618372B2 (ja) * 2008-12-22 2011-01-26 ブラザー工業株式会社 現像剤供給装置
JP2011090035A (ja) * 2009-10-20 2011-05-06 Sharp Corp 現像装置
KR102630710B1 (ko) * 2015-12-31 2024-01-26 엘지디스플레이 주식회사 엑스레이 검출기용 어레이기판, 이를 포함하는 엑스레이 검출기, 엑스레이 검출기용 어레이기판의 제조방법 및 엑스레이 검출기의 제조방법

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US3203394A (en) * 1962-10-01 1965-08-31 Xerox Corp Xerographic development apparatus
US3232190A (en) * 1963-06-28 1966-02-01 Ibm Method and apparatus for copying
US3257223A (en) * 1962-11-01 1966-06-21 Xerox Corp Electrostatic powder cloud xerographic development method and apparatus
US3306193A (en) * 1964-09-14 1967-02-28 Continental Can Co Electrostatic screen printing with magnetic conveyer and moving base electrode
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US3592166A (en) * 1968-05-28 1971-07-13 Xerox Corp Apparatus for developing electrostatic images
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US3696783A (en) * 1970-12-15 1972-10-10 Xerox Corp Automated touchdown developement system
US3696785A (en) * 1970-12-18 1972-10-10 Xerox Corp Development apparatus
US3707389A (en) * 1971-01-06 1972-12-26 Xerox Corp Latent electrostatic image development
US3739748A (en) * 1970-12-15 1973-06-19 Xerox Corp Donor for touchdown development

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Publication number Priority date Publication date Assignee Title
US2901374A (en) * 1955-05-04 1959-08-25 Battelle Development Corp Development of electrostatic image and apparatus therefor
US3040704A (en) * 1957-04-16 1962-06-26 Rca Corp Apparatus for developing electrostatic printing
US3203394A (en) * 1962-10-01 1965-08-31 Xerox Corp Xerographic development apparatus
US3257223A (en) * 1962-11-01 1966-06-21 Xerox Corp Electrostatic powder cloud xerographic development method and apparatus
US3232190A (en) * 1963-06-28 1966-02-01 Ibm Method and apparatus for copying
US3306193A (en) * 1964-09-14 1967-02-28 Continental Can Co Electrostatic screen printing with magnetic conveyer and moving base electrode
US3331355A (en) * 1965-01-04 1967-07-18 Xerox Corp Xerographic developing apparatus
US3645770A (en) * 1968-04-22 1972-02-29 Xerox Corp Improved method for developing xerographic images
US3592166A (en) * 1968-05-28 1971-07-13 Xerox Corp Apparatus for developing electrostatic images
US3696783A (en) * 1970-12-15 1972-10-10 Xerox Corp Automated touchdown developement system
US3739748A (en) * 1970-12-15 1973-06-19 Xerox Corp Donor for touchdown development
US3696785A (en) * 1970-12-18 1972-10-10 Xerox Corp Development apparatus
US3707389A (en) * 1971-01-06 1972-12-26 Xerox Corp Latent electrostatic image development

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4067295A (en) * 1975-03-07 1978-01-10 Xerox Corporation Magnetic microfield donor system
US4356245A (en) * 1977-09-10 1982-10-26 Canon Kabushiki Kaisha Method and apparatus for electrophotographic, image development with magnetic toner
US4386577A (en) * 1977-09-10 1983-06-07 Canon Kabushiki Kaisha Developing apparatus for electrostatic image
US4195991A (en) * 1977-10-21 1980-04-01 James River Graphics Inc. Electrographic recording method of applying an electric field opposite the charge retaining layer
US4666815A (en) * 1983-10-19 1987-05-19 Canon Kabushiki Kaisha Method for developing electrostatic latent image with non-magnetic toner
US4614419A (en) * 1984-09-20 1986-09-30 Xerox Corporation Pre-development inductive charging of developer material
US4978597A (en) * 1988-02-29 1990-12-18 Canon Kabushiki Kaisha Image forming method and image forming apparatus utilizing a toner-carrying member with spherical concavities
US4920381A (en) * 1989-01-03 1990-04-24 Eastman Kodak Company Toner container lift mechanism
US5040004A (en) * 1989-12-18 1991-08-13 Xerox Corporation Belt donor for direct electrostatic printing
US5119147A (en) * 1990-12-24 1992-06-02 Xerox Corporation Selective coloring of bi-level latent electostatic images
US5247317A (en) * 1991-12-12 1993-09-21 Oce-Nederland B.V. Printing device with control of developer roller spacing
US5276488A (en) * 1992-08-31 1994-01-04 Xerox Corporation Donor belt and electrode structure supported behind the belt for developing electrostatic images with toner
EP0586165A3 (en) * 1992-08-31 1996-01-17 Xerox Corp Wireless, scavengeless hybrid development
EP0601786A3 (en) * 1992-12-07 1995-07-19 Xerox Corp Correct loading of a delivery roller for hybrid development.
US6023600A (en) * 1998-08-31 2000-02-08 Xerox Corporation Ion charging developement system
US6223013B1 (en) * 1998-12-14 2001-04-24 Xerox Corporation Wire-less hybrid scavengeless development system

Also Published As

Publication number Publication date
DE2400716A1 (de) 1974-07-11
NL7400317A (enrdf_load_stackoverflow) 1974-03-25
JPS49104639A (enrdf_load_stackoverflow) 1974-10-03
CA1027427A (en) 1978-03-07
JPS5815790B2 (ja) 1983-03-28

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