US3911864A - Toner preloaded magnetic brush development system - Google Patents

Toner preloaded magnetic brush development system Download PDF

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Publication number
US3911864A
US3911864A US324467A US32446773A US3911864A US 3911864 A US3911864 A US 3911864A US 324467 A US324467 A US 324467A US 32446773 A US32446773 A US 32446773A US 3911864 A US3911864 A US 3911864A
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US
United States
Prior art keywords
developer
electrode
toner
rotatable member
photosensitive surface
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
US324467A
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English (en)
Inventor
Frederick W Hudson
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 US324467A priority Critical patent/US3911864A/en
Priority to CA189,485A priority patent/CA1027426A/en
Priority to DE2400926A priority patent/DE2400926A1/de
Priority to IT19359/74A priority patent/IT1003375B/it
Priority to CH47674A priority patent/CH568594A5/xx
Priority to FR7401271A priority patent/FR2214143B1/fr
Priority to BR292/74A priority patent/BR7400292D0/pt
Priority to JP821374A priority patent/JPS5710426B2/ja
Priority to NL7400677A priority patent/NL7400677A/xx
Priority to AU64629/74A priority patent/AU6462974A/en
Priority to BE139910A priority patent/BE809859A/xx
Application granted granted Critical
Publication of US3911864A publication Critical patent/US3911864A/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
    • G03G15/09—Apparatus for electrographic processes using a charge pattern for developing using a solid developer, e.g. powder developer using magnetic brush

Definitions

  • ABSTRACT This invention concerns magnetic brush development.
  • a biased electrode is spaced from a magnetic roller at 1 1 pp 324,467 a location just prior to the roller entering a source of developer (containing toner particles on magnetic car- 52 US. 01 118/637; 117/175 Tiers) Developer is Supplied between the magnetic 51 Int. c1.
  • G03G 15/09 roller and electrode whereby tone from the developer
  • Field of Search n 1 18/636 637 24 is attracted to the magnetic roller.
  • This invention relates to enhancing development of an electrostatic latent image and increasing development speed when utilizing a magnetic brush developsystem.
  • FIG. 1 is a view of a general xerographic copying system
  • FIG. 2 is a detailed view of one embodiment of the invention.
  • FIG. 3 is a view of another embodiment of the invention.
  • FIG. 1 Shown in FIG. 1 is a xerographic machine employing the magnetic brush development apparatus of the instant invention.
  • the elements of this machine which are constructed for continuous and automatic operation, are all conventional in the xerographic art except for the novel development apparatus, which forms the basis of the instant application.
  • 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 photoconductive layer of the xerographic surface
  • An exposure station B at which the light or radiation pattern of copy to be reproduced is projected onto the xerographic surface to dissipate the charge in the exposed areas thereof to thereby leave a latent electrostatic image of the copy to be reproduced;
  • a developing station C at which a xerographic developing matcrial, including toner particles having an electrostatic charge opposite to that of the electrostatic latent image, are moved into contact with the image bearing surface, whereby the toner particles adhere to the electrostatic latent image to form a xerographic powdered image in the configuration of the copy being reproduced;
  • a transfer station D at which the xerographic powder image is electrostatically transferred from the xerographic surface to a transfer material or a support surface;
  • a cleaning and discharge station E at which the xerographic surface is brushed to remove residual toner particles remaining thereon after image transfer, and at which the surface is exposed to a relatively bright light source to effect substantially complete discharge of any residual electrostatic charge remaining thereon.
  • the latent electrostatic images to be developed are formed on a photosensitive surface l formed in the shape of an endless belt.
  • the surfaceIO could be of any configuration including a disposable photoconductive web or sheets as well as a drum shaped reusable photoconductor.
  • the belt is adapted to be rotated about three supporting rollers l2, l4 and 16, two of which, 14 and 16 are idler rollers and the third of which, 12, is a power imparting roller driven by any convenient power source 18.
  • the movement of the photosensitive surface permits its surface to be moved past the various xerographic processing stations including the development zone C.
  • the xerographic developing apparatus is provided within a developer housing 20 formed of a non-magnetic material.
  • the lower portion of the housing is trough-like in configuration to define a sump 22 to support a quantity of two-component magnetic developer mix 24.
  • the developer employed includes image developing toner particles and larger carrier granules having magnetic properties.
  • the carrier granules may be metallic or other materials having magnetic properties either uncoated or coated with a carrier coating material so that a triboelectric charge is generated between it and the toner upon mutual interaction. This charge is necessary to effect the xerographic development of the images. Examples of such magnetic developer are described in US. Pat. No. 2,874,063 to Greig.
  • Each of these cylinders has an associated gear member (not shown) for imparting the alternating directions thereto.
  • the gears employed for rotating the cylinders are connected to a suitable source of power, not shown, for imparting motion thereto.
  • This mechanism can be the same as shown in FIG. 2 of US. Pat. No. 3,572,289 to Maksymiak.
  • a magnet 36 Located within each of the cylinders is a magnet 36, preferably permanent, with north and south poles extending the length of the magnetic cylinders with their field producing poles facing in the direction over which the developer will be moved.
  • the poles of the magnets face toward the photoconductor surface to be developed for the presentation of developing material to the image.
  • the field producing-magnets of the cylinders 28 and 32 which function to merely transport the developer, have their field producing poles in a direction away from the photoconductive surface.
  • the magnetic developer Upon reaching the uppermost position of cylinder 26, the magnetic developer is passed beyond the effect of the magnetic field of cylinder 26 into the effect of the magnetic field emanating from the next adjacent roller 28. In this manner, the developer may be magnetically attracted and then conveyed between adjacent cylinders from the uppermost position of a lower cylinder to the lowermost position of the next higher sylinder. This procedure continues until the developer contacts the uppermost roller 34 whereafter, continued cylinder rotation will permit the developer to be dropped onto a guide plate 38 inasmuch as it is no longer within the field of influence of any magnetic field producing means.
  • Located above the housing 20 is a well-known toner reservoir or dispenser 40 containing toner particles 42 therein. Toner is dispensed from the housing onto the guide plate 38.
  • chutes 44 and 46 Attached to the guide plate 38 are chutes 44 and 46 having inlet openings 48 and 50, respectively.
  • the excess developer deposited on the plate 38 by the roll 34 and the toner particles 42 discharged from the dispenser 40 slide down the guide plate 38 with a portion thereof entering inlet openings 48 and 50 of the chutes 44 and 46 and a portion thereof skipping over the chute openings onto the lower end of the plate 38 and being discharged therefrom directly into the developer sump 22.
  • the inlet openings 48 and 50 extend the length of the magnetic rollers and are of such a width as to control the amount of developer entering thereinto and passing directly to the developer sump.
  • the chutes 44 and 46 have an outlet opening 52 and 54, respectively, which extend the entire length of the magnetic lower rollers 30 and 26.
  • a pair of electrodes 56 and 58 are provided at the lower end of the chutes 44 and 46, respectively, and are spaced from a respective roller 30 and 26.
  • the electrodes are so located relative to the chute openings that the developer discharged through the openings will pass between a respective roll and electrode.
  • a duct member 59 is positioned to direct the developer flowing between the electrode 56 and roller 30 to the chute 46 where the developer joins the developer stream in chute 46 and passes between the electrode 58 and roller 26.
  • the electrodes are electrically separated from their respective chutes by an insulating member 60.
  • the electrodes 56 and 58 are coupled to a high voltage source of suitable electrical potential V whereby triboelectrically charged toner from the developer material emerging from openings 52 and 54 and passing between the electrodes 56 and roll 30 and between electrode 58 and roll 26 will be stripped from the carrier beads to develop or adhere to the rollers 30 and 26.
  • the rollers 26 and 30 are coupled to a suitable electrical potential V2 of a magnitude and polarity that in conjunction with the electrodes, they will attract the toner from the carrier beads and that the toner will be deposited on the charged latent image while suppressing background deposition of the toner.
  • the potential on the electrode V1 may be 8OO volts
  • the potential on the rollers V2 may be +300 volts
  • the latent image charge may be +800 volts
  • the background charge may be +200 volts
  • the polarity of the triboelectrically charged toner may be negative.
  • the voltage polarities may change in accordance with the polarity of the charge on the image and toner.
  • roller 26 In operation, as the roller 26 rotates, the developed portion thereof enters the developer mix 24 and as the surface thereof approaches the magnetic field imposed by magnet 36, carrier particles with their associated toner particles are attracted to the roller surface and then presented to the electrostatic latent image on the photosensitive belt for development whereby toner will be stripped from the roller surface and from the carriers.
  • carrier particles with their associated toner particles are attracted to the roller surface and then presented to the electrostatic latent image on the photosensitive belt for development whereby toner will be stripped from the roller surface and from the carriers.
  • the roller 26 brings the same surface to an attracting magnetic field of the conveying roller 28 whereby the excess developer on roll 26 is transferred thereto and the rest of the rollers as described previously.
  • the developer remaining on the upper roller 34 is discharged onto the plate 38 and is allowed to mix with the toner 42 and fiow by gravity into the chutes 44 and 46 or off the plate 38 whereby the toner becomes properly charged, the denuded carriers are retoned and the back portions of the development rolls 26 and are developed with toners.
  • roller 26 since the surface of roller 26 is precoated with toner particles, the rotational speed thereof through the developer mix can be increased and still the same total amount of toner will be presented to the latent image as a roller rotated at a normal speed which solely relies upon picking up toner when rotated through the developer mix.
  • the carrier beads are substantially stripped of toner.
  • development of the image is enhanced when utilizing rotational speeds equal to or slightly greater than the speed normally used.
  • FIG. 3 the embodiment of FIGS. 1 and 2 is modified. All elements which are the same as the previous embodiment are designated by the same reference numeral only with an a affixed thereto.
  • a bucket conveyor is utilized to convey a portion of the developer mix to an inlet opening of a split chute 104.
  • the developer is split into two streams, one down chute 104 and between the roller 26a and electrode 58a and the other down chute 106 directly to the developer mix 24a. Since only one magnetic roller is used, the bucket conveyor is utilized for circulating and mixing the developer mixfThe magnetic roller 26a is developed with toner in the same manner as the previous embodiment.
  • any number of magnetic rollers may be utilized with this invention and that in the embodiment of FIGS. 1 and 2 either the roller 26 or the roller 30 may be developed with toner without the other being developed with toner although it is preferred to develop each roller. Also, all of the rollers may be rotated in the same direction and each roller may present developer to the latent image.
  • a magnetic brush development system for an electrostatic processor to develop latent electrostatic images carried by a movable photosensitive surface through the use of a developer containing oppositely charged toner and carrier particles; said system comprising the combination of a sump for storing a supply of developer;
  • a rotatable member positioned between said sump and said photosensitive surface for transporting developer in a predetermined direction from said sump to said photosensitive surface, said rotatable member having a magnetic field emanating therefrom for loading developer on said member as it advances past said sump and for retaining said developer on said member as it advances past said photosensitive surface;
  • a magnetic brush development system for an electrostatic processor to develop latent electrostatic images carried by a movable photosensitive surface through the use of a developer containing oppositely charged toner and carrier particles; said system comprising the combination of a plurality of rotatable members extending in series from said sump along said photosensitive surface, each of said members having a magnetic field emanating therefrom and being rotatable in a predetermined direction for transporting developer from said sump along a path running between said photosensitive surface and successive ones of said members;
  • a second electrode mounted adjacent another of said members remotely from said photosensitive surface, said other member being separated in said series from said one member by at least one intervening member;
  • the development system of claim 1 further including another rotatable member positioned between said sump and the first mentioned rotatable member for transporting developer from said sump to said first mentioned member.
  • the development system of claim 1 further including at least two additional rotatable members in series with the first mentioned rotatable member, each of said additional members having a magnetic field emanating therefrom to assist in transporting developer from said sump to said photosensitive surface.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Magnetic Brush Developing In Electrophotography (AREA)
  • Dry Development In Electrophotography (AREA)
US324467A 1973-01-17 1973-01-17 Toner preloaded magnetic brush development system Expired - Lifetime US3911864A (en)

Priority Applications (11)

Application Number Priority Date Filing Date Title
US324467A US3911864A (en) 1973-01-17 1973-01-17 Toner preloaded magnetic brush development system
CA189,485A CA1027426A (en) 1973-01-17 1974-01-04 Toner preloaded magnetic brush development system
DE2400926A DE2400926A1 (de) 1973-01-17 1974-01-09 Verfahren und vorrichtung zum entwickeln eines latenten elektrostatischen bildes mit hilfe eines magnetischen buerstensystems
IT19359/74A IT1003375B (it) 1973-01-17 1974-01-11 Dispositivo e procedimento di svi luppo a spazzola magnetica parti colarmente per macchine copiatrici elettrostatiche
CH47674A CH568594A5 (ja) 1973-01-17 1974-01-14
FR7401271A FR2214143B1 (ja) 1973-01-17 1974-01-15
BR292/74A BR7400292D0 (pt) 1973-01-17 1974-01-16 Aperfeicoamentos em dispositivo de revelacao de escova magnetica e processo de revelacao de uma imagem eletrostatica latente
JP821374A JPS5710426B2 (ja) 1973-01-17 1974-01-17
NL7400677A NL7400677A (ja) 1973-01-17 1974-01-17
AU64629/74A AU6462974A (en) 1973-01-17 1974-01-17 Toner preloaded magnetic brush development system
BE139910A BE809859A (fr) 1973-01-17 1974-01-17 Machine et procede de developpement a brosse magnetique

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US324467A US3911864A (en) 1973-01-17 1973-01-17 Toner preloaded magnetic brush development system

Publications (1)

Publication Number Publication Date
US3911864A true US3911864A (en) 1975-10-14

Family

ID=23263721

Family Applications (1)

Application Number Title Priority Date Filing Date
US324467A Expired - Lifetime US3911864A (en) 1973-01-17 1973-01-17 Toner preloaded magnetic brush development system

Country Status (11)

Country Link
US (1) US3911864A (ja)
JP (1) JPS5710426B2 (ja)
AU (1) AU6462974A (ja)
BE (1) BE809859A (ja)
BR (1) BR7400292D0 (ja)
CA (1) CA1027426A (ja)
CH (1) CH568594A5 (ja)
DE (1) DE2400926A1 (ja)
FR (1) FR2214143B1 (ja)
IT (1) IT1003375B (ja)
NL (1) NL7400677A (ja)

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4063533A (en) * 1976-08-02 1977-12-20 International Business Machines Corporation Multiple brush developer applying apparatus with a toner diverter blade
US4084542A (en) * 1976-06-16 1978-04-18 Rank Xerox, Ltd. Positioning apparatus for magnetic brush developing device
US4108658A (en) * 1974-03-11 1978-08-22 Oce-Van Der Grinten N.V. Process for developing electrostatic latent images
US4131357A (en) * 1977-03-21 1978-12-26 Xerox Corporation Sequentially activated development system for an electrophotographic printer
US4131081A (en) * 1976-04-14 1978-12-26 Hitachi, Ltd. Toner concentration detecting apparatus
US4442790A (en) * 1982-09-29 1984-04-17 Eastman Kodak Company Magnetic brush development apparatus
US4496644A (en) * 1983-02-28 1985-01-29 Eastman Kodak Company Electric field adjustment for magnetic brushes
EP0161795A1 (en) * 1984-05-16 1985-11-21 Mita Industrial Co. Ltd. Developing apparatus
WO1988002506A1 (en) * 1986-09-24 1988-04-07 Siemens Aktiengesellschaft Co- and counter-rotating development system for an electro-photographic installation
US5416571A (en) * 1993-01-05 1995-05-16 Hitachi Koki Co., Ltd. Developing device for electrophotograph-type printer
US6345163B1 (en) * 1999-09-30 2002-02-05 Hitachi Koki Co. Ltd. Developing device for image forming apparatus

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS5921401Y2 (ja) * 1978-04-24 1984-06-23 富士ゼロックス株式会社 磁気ブラシ現像装置
JPS5649555U (ja) * 1979-09-21 1981-05-01

Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3203394A (en) * 1962-10-01 1965-08-31 Xerox Corp Xerographic development apparatus
US3443517A (en) * 1967-01-04 1969-05-13 Xerox Corp Electrostatic duplicating system employing relief printing plate
US3572289A (en) * 1968-09-23 1971-03-23 Xerox Corp Magnetic brush development apparatus
US3641980A (en) * 1969-10-20 1972-02-15 Xerox Corp Development apparatus
US3662711A (en) * 1970-03-19 1972-05-16 Xerox Corp Development apparatus
US3724422A (en) * 1970-12-14 1973-04-03 Xerox Corp Magnetic brush developing apparatus
US3754526A (en) * 1971-12-17 1973-08-28 Ibm Electrophotographic development apparatus

Patent Citations (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3203394A (en) * 1962-10-01 1965-08-31 Xerox Corp Xerographic development apparatus
US3443517A (en) * 1967-01-04 1969-05-13 Xerox Corp Electrostatic duplicating system employing relief printing plate
US3572289A (en) * 1968-09-23 1971-03-23 Xerox Corp Magnetic brush development apparatus
US3641980A (en) * 1969-10-20 1972-02-15 Xerox Corp Development apparatus
US3662711A (en) * 1970-03-19 1972-05-16 Xerox Corp Development apparatus
US3724422A (en) * 1970-12-14 1973-04-03 Xerox Corp Magnetic brush developing apparatus
US3754526A (en) * 1971-12-17 1973-08-28 Ibm Electrophotographic development apparatus

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4108658A (en) * 1974-03-11 1978-08-22 Oce-Van Der Grinten N.V. Process for developing electrostatic latent images
US4131081A (en) * 1976-04-14 1978-12-26 Hitachi, Ltd. Toner concentration detecting apparatus
US4084542A (en) * 1976-06-16 1978-04-18 Rank Xerox, Ltd. Positioning apparatus for magnetic brush developing device
US4063533A (en) * 1976-08-02 1977-12-20 International Business Machines Corporation Multiple brush developer applying apparatus with a toner diverter blade
US4131357A (en) * 1977-03-21 1978-12-26 Xerox Corporation Sequentially activated development system for an electrophotographic printer
US4442790A (en) * 1982-09-29 1984-04-17 Eastman Kodak Company Magnetic brush development apparatus
US4496644A (en) * 1983-02-28 1985-01-29 Eastman Kodak Company Electric field adjustment for magnetic brushes
EP0161795A1 (en) * 1984-05-16 1985-11-21 Mita Industrial Co. Ltd. Developing apparatus
WO1988002506A1 (en) * 1986-09-24 1988-04-07 Siemens Aktiengesellschaft Co- and counter-rotating development system for an electro-photographic installation
US4952979A (en) * 1986-09-24 1990-08-28 Siemens Aktiengesellschaft Isorunning-counterrunning developer station for an electrophotographic means
US5416571A (en) * 1993-01-05 1995-05-16 Hitachi Koki Co., Ltd. Developing device for electrophotograph-type printer
US6345163B1 (en) * 1999-09-30 2002-02-05 Hitachi Koki Co. Ltd. Developing device for image forming apparatus

Also Published As

Publication number Publication date
DE2400926A1 (de) 1974-07-18
FR2214143A1 (ja) 1974-08-09
FR2214143B1 (ja) 1976-10-08
CA1027426A (en) 1978-03-07
CH568594A5 (ja) 1975-10-31
JPS5041551A (ja) 1975-04-16
BR7400292D0 (pt) 1974-08-22
NL7400677A (ja) 1974-03-25
IT1003375B (it) 1976-06-10
JPS5710426B2 (ja) 1982-02-26
AU6462974A (en) 1975-07-17
BE809859A (fr) 1974-05-16

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