EP0272611A2 - Appareil de développement à brosse magnétique avec un mécanisme de passage et de mesure - Google Patents

Appareil de développement à brosse magnétique avec un mécanisme de passage et de mesure Download PDF

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Publication number
EP0272611A2
EP0272611A2 EP87118689A EP87118689A EP0272611A2 EP 0272611 A2 EP0272611 A2 EP 0272611A2 EP 87118689 A EP87118689 A EP 87118689A EP 87118689 A EP87118689 A EP 87118689A EP 0272611 A2 EP0272611 A2 EP 0272611A2
Authority
EP
European Patent Office
Prior art keywords
roller
developer material
magnetic brush
opening
sump
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.)
Granted
Application number
EP87118689A
Other languages
German (de)
English (en)
Other versions
EP0272611A3 (en
EP0272611B1 (fr
Inventor
Frank C/O Eastman Kodak Company Hacknauer
Salvatore Castrenze Eastman Kodak Company Defazio
Richard Samuel C/O Eastman Kodak Company Fox
Kenneth D. C/O Eastman Kodak Company Adkins
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.)
Eastman Kodak Co
Original Assignee
Eastman Kodak Co
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
Priority claimed from US06/944,895 external-priority patent/US4690096A/en
Priority claimed from US07/070,275 external-priority patent/US4748471A/en
Application filed by Eastman Kodak Co filed Critical Eastman Kodak Co
Publication of EP0272611A2 publication Critical patent/EP0272611A2/fr
Publication of EP0272611A3 publication Critical patent/EP0272611A3/en
Application granted granted Critical
Publication of EP0272611B1 publication Critical patent/EP0272611B1/fr
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
    • G03G15/0822—Arrangements for preparing, mixing, supplying or dispensing developer
    • 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

  • the present invention relates to magnetic bursh development apparatus for use with electrographic copiers/duplicators or the like and, more particularly, to an improved apparatus for controlling the flow of developer material to the magnetic brush.
  • U.S. Patent No. 4,538,896 It is known from U.S. Patent No. 4,538,896 to provide toner to a development station in a hopper.
  • the hopper is closed by a plate that is rotated to allow toner to fall through an opening in the hopper to a magnetic brush.
  • U.S. Patent No. 3,523,518 discloses dispensing of toner from a cartridge having a series of holes therein by rotating the cartridge and allowing toner to fall through the holes in the cartridge under the influence of gravity.
  • the Japanese publication teaches the delivery of developer material from a sump to a magnetic brush for developing latent images by means of a transport roll located between the sump and the magnetic brush.
  • the magnetic brush comprises a developer roll that is rotated in one direction to deliver developer material from the transport roll to the photoconductor.
  • the developer roll is stopped and then rotated in the oppostie direction so that a developer-free part of the developer roll faces the photoconductor to thereby stop application of developer to the photoconductor.
  • This object is accomplished with an electrographic apparatus having the above features which is characterized by a movable gating member positioned around a developer transport roller and having first and second openings so that when the gating member is in a first position developer material can be delivered from the sump through the openings to the magnetic brush, and when the gating member is in a second position the flow of developer material to the magnetic brush is blocked by the gating member.
  • a development station of an electrographic apparatus is generally designated 10 and comprises a housing 12 that defines a sump 14 for receiving developer material.
  • a photoconductor 16 travels across the upper portion of the housing 12 in the direction shown by the arrow and contains on its lower surface one or more latent electrostatic images that are developed by developer material from sump 14. The developed images can be transferred to a copy sheet and fused thereto in a known manner or fused onto the photoconductor itself.
  • the development station 10 has a magentic brush 18 for applying developer material to the images on photoconductor 16.
  • the brush illustrated comprises a core 20 having a plurality of magnets 22 spaced around the core, and a cylindrical, non magnetic shell 24 that surrounds the core 20.
  • the core and/or shell can be fixed or rotatable, as known in the art.
  • the core 20 is rotatable in a counterclockwise direction, and the shell rotates in a clockwise direction to thereby feed developer material in a clockwise direction to the photoconductor.
  • a blade 25 engages the shell 24 downstream of the development zone between the shell and photoconductor to remove unused developer material from the shell and return it to the sump.
  • Blender 26 comprises a shaft 28 that is rotatable about its axis and has a plurality of rods 30 projecting therefrom.
  • the rods carry inner and outer helical ribbons 32, 34.
  • the pitch of the ribbon 32 is opposite from ribbon 34 so that when the shaft 28 is driven in a counterclockwise direction as shown in Fig. 1, ribbon 32 tends to drive developer material in one direction through the sump 14 while ribbon 34 tends to drvie the material in the opposite direction.
  • the feeding mechanism is located between the top of the ribbon blender and the bottom of the magnetic brush.
  • the feeding mechanism includes a shaft 38 that can be driven in a clockwise direction.
  • a generally cylindrical transport roller 40 surrounds shaft 38 and is connected to it so that the roller is driven when the shaft is rotated.
  • the outer surface of roller 40 is deeply fluted as shown at 42 to form a plurality of recesses and ridges that extend axially along the roller. The surface could also be grooved, or otherwise roughened or textured.
  • the fluted surface picks up developer material from the lower quadrant of the gating member and transports it to the magnetic brush as described in more detail later.
  • the roller can be made from any suitable material, such as extruded aluminum, plastic, etc.
  • statinary permanent magnet 44 Between the roller 40 and shaft 38 there is a statinary permanent magnet 44.
  • the magnet is located beneath the shaft 38 and to the left thereof, and generally above and to the left of the ribbon blender 26.
  • the magnet illustrated in the drawings extends through an arc of about 80 degrees. It is located so that developer material mixed by the ribbon blender is attracted to the outer surface of the roller 40 by the magnet 44 and held on the roller by the magnet as it is transported in a clockwise direction by the roller toward the magnetic brush.
  • the postion of the magnet together with its arcuate dimension, assures that the material will be held onto the roller until it reaches a point where the material can be held onto the roller by the flutes 42 only.
  • roller 40 helps to transport the developer material from the sump to a position where it can be attracted to the magnetic brush by the magnets 22 in the brush.
  • a gating and metering mechanism 45 includes a gating tube 46 which is positioned around the roller 40 and is spaced therefrom in order to provide an annular space for the flow of developer material betwen the roller and the tube 46.
  • the tube is an elongate cylindrical member and can be made of plastic or other suitable materials.
  • the tube is concentric with roller 40 and extends along the development station substantially the same distance as the magnetic brush 18.
  • Tube 46 has an elongate, relatively wide slot 48 and a much narrower elongate slot 50. Both slots are generally rectangular in shape and extend substantially the full length of brush 18 and tube 46. The width of each slot extends circumferentially along the tube so that each slot has two opposed longitudinally extending side edges.
  • slots 48, 50 are approximately 205-210 degrees apart. The spacing of the slots depends, in part, on the location of the feeding mechanism 36 and gating mechanism 45 relative to the blender 26 and magnetic brush 18. The slots are spaced so that when the tube is in the position illustrated in Fig. 1 the wider slot 48 is substantially aligned with the bottom of roller 40 and between the magnet 44 and the ribbon blender. Also, when the tube is in the Fig. 1 position the slot 50 extends along the portion of tube 46 that is nearest to the shell 24 of the magnetic brush 18.
  • Slot 48 is relatively wide so that a substantial amount of developer material from sump 14 can pass through slot 48 and enter the space between tube 46 and roller 40 to be transported by roller 40 to the slot 50.
  • Slot 50 is much narrower and meters the desired amount of developer material to the magnetic brush.
  • the slots may have various dimensions, depending upon a number of factors. By way of example, slot 48 can be approximately .50 inch wide and slot 50 can be approximately .045 inch wide. These dimensions can provide a developer flow rate of approximately 3.2 grams per inch per second to the magnetic brush.
  • Tube 46 is oscillated between the positions shown in Fig. 1 and Fig. 2 to control the flow of developer material to the magnetic brush. Such movement can be accomplished in any sutiable manner.
  • a pin 52 secured to the tube 46 can be coupled to a solenoid 54, as shown diagrammatically at 56, so that the solenoid is effective to move the tube between its two positions.
  • the solenoid can be controlled from the logic and contol unit of the associated electrographic apparatus so that it is actuated at precisely the correct time relative to the movement of images on the photoconductor past the development station.
  • slot 48 is between the ribbon blender and the magnet 44 so that developer material from the sump can be driven by the ribbon blender through the slot.
  • Such material is attracted to roller 40 by the magnet 44.
  • Roller 40 transports the material to the top of the roller where it is attracted toward the magnetic brush 18 by magnets 22 in the core of the magnetic brush. Thus some of the developer material will flow through the smaller slot 50 to the magnetic brush.
  • the tube In order to shut off the flow of developer material to the magneitc brush, the tube is rotated approximately 60 degrees from its Fig. 1 position to its Fig. 2 position. At this time the larger slot 48 is spaced from the ribbon blender and the sump so that material from the ribbon blender and sump cannot pass through the slot into the space between the tube 46 and roller 40. Also, the smaller slot 50 is spaced from the magnetic brush. When slot 50 is in its Fig. 2 position, any developer material flowing through the slot from the space between the tube 46 and roller 40 falls under the influence of gravity back into the sump 14. At this time the material is too far from the magnets 22 to be attracted to the magentic brush.
  • Movement of the tube 46 between its two positions can be effected very rapidly to quickly and reliably start or stop the flow of developer material to the magnetic brush. This is especially desirable when the apparatus is used in color copiers where a series of similar development stations would be used, each with different colored toners, and wherein the flow of one color developer material to the magnetic brush must be stopped and started quickly and with great accuracy in order to avoid contamination of an adjacent image on the photoconductor.
  • Figs. 3 and 4 illustrate another embodiment wherein means generally designated 60 are provided to immediately shut off the flow of developer material to magnetic brush 18 through slot 50 when the tube 46 is rotated.
  • the shut-off means 60 illustrated comprises an elongate plate 62 having one end portion 62a secured to a bar 27. Blade 25 also is connected to the bar.
  • the other end portion 62b of plate 62 is in sliding contact with the outer surface of tube 46 closely adjacent to the right longitudinal side edge of slot 50 when the tube is in the portion shown in Fig. 3.
  • End portion 62b preferably is curved so the free end of the plate is elevated slightly from the surface of the tube to avoid "stubbing" of the end of the plate in slot 50 as the tube is rotated from its Fig. 3 position to its Fig. 4 position.
  • the plate is thin and flexible, and is flexed when mounted on the bar and resting on tube 46. Because of this construction and mounting, end portion 62b bears against the surface of the tube and maintains sliding contact with the tube. The pressure exerted by the plate against the tube effectively seals the interface therebetween and avoids passage of developer material between the plate and tube.
  • the plate extends the full length of slot 50 so that the plate covers the slot and blocks the flow of developer material from slot 50 to the magnetic brush 18 when tube 46 is rotated a few degrees from its position illustrated in Fig. 3 to its position illustrated in Fig. 4.
  • the plate is made of brass or other suitable low friction material so that the plate does not significantly increase the torque required to rotate the tube 46.
  • slot 48 is between the ribbon blender and the magnet 44 so that developer material from the sump can be driven by the ribbon blender through the slot.
  • Such material is attracted to roller 40 by the magnet 44.
  • Roller 40 transports the material to the top of the roller where it is attracted toward the magnetic brush 18 by magnets 22 in the core of the magnetic brush.
  • some of the developer material will flow through the smaller slot 50 to the magnetic brush without interference from plate 62.
  • the tube In order to shut off the flow of developer material to the magnetic brush, the tube is rotated a few degrees clockwise, for example approximately 5 degrees, from its Fig. 3 position to its Fig. 4 position. As this rotation occurs, the slot 50 passes under plate portion 62b, and portion 62b then contacts the tube 46 adjacent the left longitudinal side edge of the slot. This slight movement immediately shuts off the flow of developer material to magnetic brush 18 through slot 50. Developer material flowing through slot 50 then travels along the bottom surface of plate or along tube 46 until gravity returns the material to sump 14. The pressure contact between plate end portion 62b and tube 46 prevents glow of developer material therebetween to the brush 18.
  • Movement of the tube 46 between its Fig. 3 and Fig. 4 positions can be effected very rapidly due to the short distance required to move the tube. Also, the space between tube 46 and roller 40 remans substantially full of developer material even when the tube is in the position shown in Fig. 4. This makes it possible to quickly and reliably start, as well as stop, the flow of developer material to the magnetic brush. This is especially desirable when the apparatus is used in copiers where two or more similar development stations are used, each with developer material having different colored toners that are to be applied to adjacent images on the photoconductor and wherein the adjacent images are separated by a small "interframe" distance of about 3.75 cm., for example.

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Magnetic Brush Developing In Electrophotography (AREA)
EP87118689A 1986-12-22 1987-12-16 Appareil de développement à brosse magnétique avec un mécanisme de passage et de mesure Expired - Lifetime EP0272611B1 (fr)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US944895 1986-12-22
US06/944,895 US4690096A (en) 1986-12-22 1986-12-22 Magnetic brush development apparatus having a gating and metering mechanism
US70275 1987-07-06
US07/070,275 US4748471A (en) 1987-07-06 1987-07-06 Development apparatus having means for rapidly shutting off the flow of developer to a magnetic brush

Publications (3)

Publication Number Publication Date
EP0272611A2 true EP0272611A2 (fr) 1988-06-29
EP0272611A3 EP0272611A3 (en) 1989-06-14
EP0272611B1 EP0272611B1 (fr) 1992-08-19

Family

ID=26750980

Family Applications (1)

Application Number Title Priority Date Filing Date
EP87118689A Expired - Lifetime EP0272611B1 (fr) 1986-12-22 1987-12-16 Appareil de développement à brosse magnétique avec un mécanisme de passage et de mesure

Country Status (3)

Country Link
EP (1) EP0272611B1 (fr)
JP (1) JPH0614227B2 (fr)
DE (1) DE3781258T2 (fr)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0298504B1 (fr) * 1987-07-09 1992-03-25 Sharp Kabushiki Kaisha Appareil de développement

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3031593A1 (de) * 1979-08-21 1981-03-19 Ricoh Co., Ltd., Tokyo Entwickungseinrichtung mit magnetischer buerste fuer ein elektrophotographisches kopiergeraet
EP0160830A1 (fr) * 1984-04-06 1985-11-13 EASTMAN KODAK COMPANY (a New Jersey corporation) Appareil de développement électrographique comprenant un dispositif de mixage avec un mélangeur à ruban
US4671207A (en) * 1985-12-11 1987-06-09 Eastman Kodak Company Magnetic brush development apparatus
US4716437A (en) * 1986-11-19 1987-12-29 Eastman Kodak Company Development station having apertured thin film for controlling the flow of developer material

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6020751B2 (ja) * 1977-04-25 1985-05-23 株式会社リコー 磁気ブラシ現像装置
JPS5555370A (en) * 1978-10-20 1980-04-23 Ricoh Co Ltd Magnetic brush developing unit
JPS5811766U (ja) * 1981-07-15 1983-01-25 株式会社日立製作所 現像装置
JPS60136777A (ja) * 1983-12-26 1985-07-20 Ricoh Co Ltd 複写装置の現像装置

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE3031593A1 (de) * 1979-08-21 1981-03-19 Ricoh Co., Ltd., Tokyo Entwickungseinrichtung mit magnetischer buerste fuer ein elektrophotographisches kopiergeraet
EP0160830A1 (fr) * 1984-04-06 1985-11-13 EASTMAN KODAK COMPANY (a New Jersey corporation) Appareil de développement électrographique comprenant un dispositif de mixage avec un mélangeur à ruban
US4671207A (en) * 1985-12-11 1987-06-09 Eastman Kodak Company Magnetic brush development apparatus
US4716437A (en) * 1986-11-19 1987-12-29 Eastman Kodak Company Development station having apertured thin film for controlling the flow of developer material

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
PATENT ABSTRACTS OF JAPAN *
PATENT ABSTRACTS OF JAPAN, vol. 6 no. 156 (P135)(1034), 17th August 1982; & JP-A-5772163 *

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0298504B1 (fr) * 1987-07-09 1992-03-25 Sharp Kabushiki Kaisha Appareil de développement

Also Published As

Publication number Publication date
DE3781258D1 (de) 1992-09-24
JPH0614227B2 (ja) 1994-02-23
EP0272611A3 (en) 1989-06-14
EP0272611B1 (fr) 1992-08-19
DE3781258T2 (de) 1993-03-25
JPS63167388A (ja) 1988-07-11

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