US3453045A - Xerographic development apparatus - Google Patents

Xerographic development apparatus Download PDF

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Publication number
US3453045A
US3453045A US625335A US3453045DA US3453045A US 3453045 A US3453045 A US 3453045A US 625335 A US625335 A US 625335A US 3453045D A US3453045D A US 3453045DA US 3453045 A US3453045 A US 3453045A
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US
United States
Prior art keywords
toner
toner particles
xerographic
carrier
image
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
US625335A
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English (en)
Inventor
Joseph Fantuzzo
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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
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Publication of US3453045A publication Critical patent/US3453045A/en
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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
    • G03G15/0801—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
    • G03G15/0822—Arrangements for preparing, mixing, supplying or dispensing developer
    • G03G15/0877—Arrangements for metering and dispensing developer from a developer cartridge into the development unit
    • 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
    • G03G15/0822—Arrangements for preparing, mixing, supplying or dispensing developer
    • G03G15/0887—Arrangements for conveying and conditioning developer in the developing unit, e.g. agitating, removing impurities or humidity
    • G03G15/0891—Arrangements for conveying and conditioning developer in the developing unit, e.g. agitating, removing impurities or humidity for conveying or circulating developer, e.g. augers

Definitions

  • a xerographic plate comprising a layer of photoconductive insulating material on a conductive backing is given a uniform electric charge overits surface and is then exposed to the subject matter to be reproduced, usually conventional projection techniques. This exposure discharges the plate areas in accordance with the light intensity that reaches them, and thereby creates an electrostatic latent image onor in the photoconductive layer. Development of the latent image is effected with an electrostatically charged, finely divided material, such as an electroscopic powder, which is brought into surface contact with the photoconductive layer and is held thereon electrostatically in a powder image pattern corresponding to the electrostatic latent image. Thereafter, the developed xerographic powder image is usually transferred to a support surface, such as a sheet of copy paper to which it may be fixed by any suitable means.
  • a support surface such as a sheet of copy paper
  • a commonly used developing material in electrostatic copying devices consists of a pigmented resinous powder referred to as toner and a coarse granular material called carrier.
  • the carrier is removed in the triboelectric series from the toner so that a charge is generated between the powder and the granular carrier upon mutual interaction. Such charge causes the toner to adhere to the carrier.
  • the carrier besides providing a charge to the toner, permits mechanical control so that the toner can readily be brought into contact with the exposed xerographic surface.
  • the toner particles are electrostatically attracted to the electrostatic image to produce a visible powder image.
  • the quality of the developed image may be affected by the ratio of toner particles to carrier commonly referred to as toner concentration. For example, if there is a deficiency of toner, the image areas will be unable to attract sufficient toner to fully develop the image resulting in light images. On the other hand, if there is an excess amount of toner in a developer material, the image 3,453,045 Patented July 1, 1969 areas become overly dark with quantities of toner becoming attached to non-image areas. The reason for this is that the attractive force holding toner particles on a carrier bead is inversely proportional to the number of particles on such bead.
  • the toner concentration in a two component developer mixture is maintained at a predetermined optimum degree continuously and automatically. More than this, the toner concentration is maintained across the entire development zone to obviate the problem of sporadic development. Generally speaking, this is accomplished by adding toner in response to and in proportion to the electrostatic property of the developer mixture prior to its movement into contact with the latent electrostatic image to be developed.
  • Another object of the invention is to dispense toner particles into a two component developer mixture equal to the amount of toner depleted through the development of the images.
  • Another object of the invention is to achieve optimum control for the toner concentration of developer material.
  • a further object of the invention is to maintain optimum toner concentration in a developer material uniformly across the development zone irrespective of the type images developed.
  • a still further object of this invention is to selectively regulate toner dispensing in an automatic copying machine so as to maintain high quality prints continuously.
  • the underlying principle of the instant invention is the attractive electrostatic force exhibited by a carrier on a toner particle due to their relative locations on the triboelectric scale.
  • carrier attracts toner to its surface its electrostatic attraction for additional toner decreases in proportion to the amount of toner already being held on its surface.
  • the addition of toner to carrier is self-regulating.
  • a xerographic system adapted for continuous and automatic operation employing a toner dispenser generally designated constructed in accordance with the invention.
  • a xerographic surface 12 formed in the Shape of a drum is mounted on a shaft 14 for movement to pass the several xerographic processing station in a direction indicated by the arrow.
  • the elements of the systems are conventional with the exception of those at the developing station which forms the basis of the present invention.
  • the several xerographic processing stations in the path of movement of the xerographic surface may be briefly described as follows:
  • a charging station A at which a uniform electrostatic charge is deposited on the xerographic surface by a corona charging device 16.
  • a transfer station D at which the xerographic powder image is electrostatically transferred from the drum surface to a transfer material 20 transported on reels 22 and 24 by another corona charging device 26.
  • the image is permanently affixed to transfer material 20 by a fuser 27.
  • a drum cleaning and discharge station E at which the drum surface is contacted by a brush 30 to remove residual toner particles remaining thereon after image transfer, and at which the drum surface is exposed to a relatively bright light source 32 to effect substantially complete discharge of any residual electrostatic charge remaining thereon.
  • development station C includes a housing 33 having a lower or sump portion for accumulating developer material 36.
  • Developer material 36 preferably takes the form of any suitable electroscopic toner mixed with a suitable granular carrier. Typical compositions for this mixture and for toners per se are more fully described in US. Patents 2,618,551 to Walkup, 2,618,552 to Wise, 2,638,416 to Walkup and Wise, 2,788,288 to Rheinfrank, 2,753,308 to Landrigan, 2,891,011 and 3,079,342 to Insalaco, and Re. 25,135 to Carlson.
  • the size and color of the toner particles depend upon the purpose intended as, for example, the
  • Patent 3,079,342 size of xerographic toner in US. Patent 3,079,342 is about 1 to about 30 microns.
  • These toners usually consists of an electroscopic resin and a colorant, such as, any suitable organic or inorganic pigment or dye.
  • the carrier granules on the other hand, generally range from 250 to 650 microns.
  • a bucket-type conveyor 38 used to carry the developer material to the upper portion of the developer housing from where the developer material is cascaded over a chute 39 onto the drum.
  • toner particles of the developer material adhere electrostatically to the previously formed electrostatic latent image area on the drum to form a visible xerographic powder image.
  • toner particles consumed during development were replenished by a gravity drop toner dispenser positioned adjacent the conveyor on the side remote from the xerographic drum.
  • Toner dispenser 10 comprises a cylindrical roller 40 mounted on a shaft 42 journaled in housing 33 above chute 39. Shaft 42 is connected to a motor 43 for rotating the roller in the direction indicated by the arrow. Cylindrical roller 40 extends parallel to chute 39 and is coextensive with drum 12 as well as the buckets of con- 'veyor 38. As shown in the figure the roller is formed of an inner core 45 made of conductive material and an outer cover 47 made of material having triboelectric characteristics similar to the carrier granules mentioned above for a purpose to be described.
  • a hopper 50 Spanning cylindrical roller 40 in abutting relationship therewith is a hopper 50 for containing a supply of toner particles 52 to replenish toner particles depleted from developer material 36.
  • Hopper 50 has a lid cover 54 at the top portion through which toner particles can be supplied.
  • a lid cover 54 At the bottom is an elongated opening through which cylindrical roller 40 is received along its longitudinal extent.
  • Rotary seals 55, 57 are journaled at the bottom of the hopper ends to provide a suitable mating surface for the hopper with cylindrical roller 40 as it is rotated on its shaft.
  • toner particles 52 from cylindrical roller 40 to carrier granules in developer material 36 will continue until such time as the electrostatic attraction of the carrier granules equals that of cover 47. At this time the developer material 36 has reached its toner saturation level.
  • a variable DC potential source 70 is connected to core 45 of cylindrical roller '40.
  • potential source 70 which has a polarity opposite to the toner, is raised or lowered, respectively, to vary the electrostatic attraction of toner 52 to cover 47 of the roller. It has been found that voltages ranging from about 3000 to 6000 volts are effective with cover thicknesses ranging from about .001" to about .007". Optimum voltage will depend upon such factors as the particular thickness of cover 47 and the relative speed at which the developer material passes the roller.
  • an improved apparatus for dispensing toner particles comprising guide means arranged to direct developer material including carrier granules at least partially covered by electroscopic toner particles for movement toward a development zone,
  • roller means mounted for rotation on an axis extending transverse to the path of movement of the developer material and closely spaced thereto,
  • roller means including a core portion and a cover portion, said cover portion having essentially the same triboelectric property as said carrier granules, and
  • hopper means positioned adjacent said roller means enclosing a supply of toner particles to be dispensed, said hopper means terminating in an elongated opening overlying said cover portion to its longitudinal extent whereby upon rotation of said roller means a predetermined portion of enclosed toner particles is transported into close proximity with the developer material path for electrostatic deposition on individual carrier granules in an amount inversely proportional to the coverage of toner particles thereon.
  • an exposure station for exposing the charged surface to an electromagnetic radiation image to form a latent electrostatic image thereon
  • said development station comprising guide means arranged to direct two-component developer material including carrier granules at least partially covered by finely divided electroscopic toner particles triboelectrically removed from the carrier granules for movement toward a development zone,
  • roller means mounted for rotation on an axis extending transverse to the path of movement of the developer material and closely spaced thereto,
  • roller means including a core portion and a cover portion, said cover portion having essentially the same triboelectric property as said carrier granules, and
  • hopper means positioned adjacent said roller means enclosing a supply of toner particles to be dispensed, said hopper means terminating in an elongated opening overlying said cover portion to its longitudinal extent whereby upon rotation of said roller means a predetermined portion of enclosed toner particles is transported into close proximity with the developer material path for electrostatic deposition on individual carrier granules in an amount inversely proportional to the coverage of toner particles thereon.
  • Apparatus according to claim 4 wherein said core portion is electrically conductive and is coupled to a DC source potential of a polarity opposite to the triboelectric polarity of said toner particles.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Dry Development In Electrophotography (AREA)
  • Magnetic Brush Developing In Electrophotography (AREA)
US625335A 1967-03-23 1967-03-23 Xerographic development apparatus Expired - Lifetime US3453045A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US62533567A 1967-03-23 1967-03-23

Publications (1)

Publication Number Publication Date
US3453045A true US3453045A (en) 1969-07-01

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Application Number Title Priority Date Filing Date
US625335A Expired - Lifetime US3453045A (en) 1967-03-23 1967-03-23 Xerographic development apparatus

Country Status (6)

Country Link
US (1) US3453045A (de)
DE (1) DE1772023A1 (de)
FR (1) FR1559973A (de)
GB (1) GB1213493A (de)
NL (1) NL6803924A (de)
SU (1) SU371739A3 (de)

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3635553A (en) * 1969-09-22 1972-01-18 Xerox Corp Cascade developing apparatus utilizing a rotary wheel with scoops
US3662711A (en) * 1970-03-19 1972-05-16 Xerox Corp Development apparatus
US3667422A (en) * 1967-11-20 1972-06-06 Saladin Ag Apparatus for transferring a particulate material to a web
US3697169A (en) * 1971-01-06 1972-10-10 Xerox Corp Electrostatic recording apparatus and method
US3911865A (en) * 1973-03-30 1975-10-14 Xerox Corp Toner pickoff apparatus
US3937570A (en) * 1971-06-03 1976-02-10 Xerox Corporation Cloud suppression in an electrostatic copying apparatus
US3951539A (en) * 1974-10-15 1976-04-20 Xerox Corporation Electrostatic reproduction machine with improved toner dispensing apparatus
DE2836509A1 (de) * 1977-08-24 1979-03-08 Minolta Camera Kk Automatische tonernachfuellvorrichtung
US4288518A (en) * 1978-12-13 1981-09-08 Minolta Camera Kabushiki Kaisha Electrographic magnetic developing method
US4347299A (en) * 1978-08-16 1982-08-31 Minolta Camera Kabushiki Kaisha Method of controlling toner concentration for electrophotographic copying apparatus
US4576465A (en) * 1982-09-24 1986-03-18 Mita Industrial Co., Ltd. Method and apparatus for adjusting toner concentration of two-component type developer
US20060249873A1 (en) * 1999-11-02 2006-11-09 Smith John S Methods for forming openings in a substrate and apparatuses with these openings and methods for creating assemblies with openings
US20070092654A1 (en) * 1999-11-02 2007-04-26 Smith John S Methods and apparatuses for fluidic self assembly
US7615479B1 (en) 2004-11-08 2009-11-10 Alien Technology Corporation Assembly comprising functional block deposited therein

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3013703A (en) * 1958-11-28 1961-12-19 Xerox Corp Powder dispensing apparatus
US3094049A (en) * 1961-02-03 1963-06-18 Xerox Corp Xerographic developer measuring apparatus
US3152012A (en) * 1960-12-19 1964-10-06 Ibm Apparatus for the development of electrostatic images
US3376854A (en) * 1966-06-01 1968-04-09 Xerox Corp Automatic toner dispensing control

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3013703A (en) * 1958-11-28 1961-12-19 Xerox Corp Powder dispensing apparatus
US3152012A (en) * 1960-12-19 1964-10-06 Ibm Apparatus for the development of electrostatic images
US3094049A (en) * 1961-02-03 1963-06-18 Xerox Corp Xerographic developer measuring apparatus
US3376854A (en) * 1966-06-01 1968-04-09 Xerox Corp Automatic toner dispensing control

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3667422A (en) * 1967-11-20 1972-06-06 Saladin Ag Apparatus for transferring a particulate material to a web
US3635553A (en) * 1969-09-22 1972-01-18 Xerox Corp Cascade developing apparatus utilizing a rotary wheel with scoops
US3662711A (en) * 1970-03-19 1972-05-16 Xerox Corp Development apparatus
US3697169A (en) * 1971-01-06 1972-10-10 Xerox Corp Electrostatic recording apparatus and method
US3937570A (en) * 1971-06-03 1976-02-10 Xerox Corporation Cloud suppression in an electrostatic copying apparatus
US3911865A (en) * 1973-03-30 1975-10-14 Xerox Corp Toner pickoff apparatus
US3951539A (en) * 1974-10-15 1976-04-20 Xerox Corporation Electrostatic reproduction machine with improved toner dispensing apparatus
US4230070A (en) * 1977-08-24 1980-10-28 Minolta Camera Kabushiki Kaisha Device for automatically replenishing toner to dry-type developing apparatus for electrophotography
DE2836509A1 (de) * 1977-08-24 1979-03-08 Minolta Camera Kk Automatische tonernachfuellvorrichtung
US4347299A (en) * 1978-08-16 1982-08-31 Minolta Camera Kabushiki Kaisha Method of controlling toner concentration for electrophotographic copying apparatus
US4288518A (en) * 1978-12-13 1981-09-08 Minolta Camera Kabushiki Kaisha Electrographic magnetic developing method
US4576465A (en) * 1982-09-24 1986-03-18 Mita Industrial Co., Ltd. Method and apparatus for adjusting toner concentration of two-component type developer
US20060249873A1 (en) * 1999-11-02 2006-11-09 Smith John S Methods for forming openings in a substrate and apparatuses with these openings and methods for creating assemblies with openings
US20070092654A1 (en) * 1999-11-02 2007-04-26 Smith John S Methods and apparatuses for fluidic self assembly
US7531218B2 (en) * 1999-11-02 2009-05-12 Alien Technology Corporation Methods and apparatuses for fluidic self assembly
US7615479B1 (en) 2004-11-08 2009-11-10 Alien Technology Corporation Assembly comprising functional block deposited therein

Also Published As

Publication number Publication date
FR1559973A (de) 1969-03-14
DE1772023A1 (de) 1971-01-07
NL6803924A (de) 1968-09-24
GB1213493A (en) 1970-11-25
SU371739A3 (de) 1973-02-22

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