EP0161795B1 - Developing apparatus - Google Patents

Developing apparatus Download PDF

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Publication number
EP0161795B1
EP0161795B1 EP19850302499 EP85302499A EP0161795B1 EP 0161795 B1 EP0161795 B1 EP 0161795B1 EP 19850302499 EP19850302499 EP 19850302499 EP 85302499 A EP85302499 A EP 85302499A EP 0161795 B1 EP0161795 B1 EP 0161795B1
Authority
EP
European Patent Office
Prior art keywords
developer
stirring
roller
sleeve
developing apparatus
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
Application number
EP19850302499
Other languages
German (de)
English (en)
French (fr)
Other versions
EP0161795A1 (en
Inventor
Yasushi Kamezaki
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.)
Kyocera Mita Industrial Co Ltd
Original Assignee
Mita Industrial Co Ltd
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 JP7252884U external-priority patent/JPS60184068U/ja
Priority claimed from JP7252984U external-priority patent/JPS60184069U/ja
Priority claimed from JP7252784U external-priority patent/JPS60184067U/ja
Application filed by Mita Industrial Co Ltd filed Critical Mita Industrial Co Ltd
Publication of EP0161795A1 publication Critical patent/EP0161795A1/en
Application granted granted Critical
Publication of EP0161795B1 publication Critical patent/EP0161795B1/en
Expired legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B07—SEPARATING SOLIDS FROM SOLIDS; SORTING
    • B07B—SEPARATING SOLIDS FROM SOLIDS BY SIEVING, SCREENING, SIFTING OR BY USING GAS CURRENTS; SEPARATING BY OTHER DRY METHODS APPLICABLE TO BULK MATERIAL, e.g. LOOSE ARTICLES FIT TO BE HANDLED LIKE BULK MATERIAL
    • B07B9/00—Combinations of apparatus for screening or sifting or for separating solids from solids using gas currents; General arrangement of plant, e.g. flow sheets
    • 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 a developing apparatus using a two-component type developer. More specifically, the present invention relates to a developing apparatus using a two-component type developer, in which stirring mixing of a toner and a carrier is effectively accomplished.
  • a developing method using a two-component type developer comprising a magnetic carrier and a toner As methods for developing an electrostatic latent image with a magnetic brush, there are known a developing method using a two-component type developer comprising a magnetic carrier and a toner and a developing method using a one-component type developer comprising toner particles alone.
  • the former method is advantageous in that charges can be given to the toner stably, and the latter method is advantageous in that the troublesome operation of adjusting the toner concentration is not necessary and the property of reproducing a halftone correctly is higher than in the former method.
  • a reproduced image should have a high contrast, that is, a clear shade, and a halftone should be beautifully reproduced.
  • the developing method using a one-component type developer is effective for satisfying these requirements.
  • the upper threshold value of the developing condition is ordinarily determined by the force of magnetically attracting the developer to the developing sleeve and the Coulomb force to the electrostatic latent image and the magnetic material is dispersed in the binder resin in the one-component type developer, the magnetic attractive force of the one-component type developer to the sleeve is weaker than that of the magnetic carrier and hence, fogging is readily caused in the developing method using a one-component type developer.
  • the earing length of the magnetic brush is shortened so as to prevent occurrence of fogging.
  • troubles as insufficient earing and reduction of the flowability of the developer are caused and when the copying machine is continuously used, if a foreign substance such as paper dust is incorporated into the magnetic brush, stable earing becomes difficult.
  • the size of the developing apparatus becomes.larger than the size of the developing apparatus used for the reverse direction development method. The reason is as follows.
  • a developing apparatus using a two-component type developer which comprises a hopper provided with a toner feed roller, a developer delivery sleeve rotating in a direction reverse to the rotation direction of a photosensitive drum and having a magnet arranged in the interior thereof, a stirring roller for effecting frictional charging of toner particles and uniform mixing of a toner and a carrier, said stirring roller rotating in the same direction as the rotation direction of the developer delivery sleeve and being provided with a plurality of stirring vanes, an earing plate for controlling the earing length of a magnetic brush formed on the developer flow guiding mechanism arranged above the stirring roller, wherein the top end of each stirring vane is bent in the rotation direction of the stirring roller and a notch is formed on each stirring vane, a spiral passage is formed on the stirring roller by the notches of the stirring vanes, and the developer flow guiding mechanism comprises a partition plate and a plurality of guide plates arranged at predetermined intervals at least
  • FIG. 1 is a sectional view diagrammatically illustrating the developing apparatus according to the present invention
  • this developing apparatus entirely represented by reference numeral 3 is arranged to construct a copying machine together with a photosensitive drum 2 rotating in a direction of arrow 1.
  • the developing apparatus 3 comprises a non-magnetic cylindrical sleeve 6 rotating in a direction of arrow 5 and having, arranged in the interior thereof on the side of the photosensitive drum 2, a magnet 4 having a plurality of magnetic poles on the surface, a developer stirring roller 8 provided with a plurality of stirring vanes 7, a developer flow guiding mechanism 9 located above the stirring roller 8, a toner hopper 11 arranged above the falling position of the developer falling from the developer flow guiding mechanism 9 onto the stirring roller 8 and provided with a toner feed roller 10, and an earing plate 12 for controlling the earing length of a magnetic brush formed on the sleeve 6 to a predetermined constant length.
  • these members are contained in a housing 20.
  • the developer travels along a course described below.
  • the developer comprising a toner and a carrier forms a magnetic brush 13 on the sleeve 6 by the action of the magnet 4 arranged in the interior of the sleeve 6, and this magnetic brush 13 is delivered to a developing zone 14 with rotation of the sleeve 6.
  • a toner image corresponding to an electrostatic latent image on the surface of the photosensitive drum is formed and development is effected.
  • the magnetic brush 13 in which the toner has been consumed is moved to a developer scraping zone 15 with rotation of the sleeve 6. Since the scraper zone 15 is adjacent to poles of the same polarity of the magnet, the developer receives a repulsive magnetic field and is separated from the sleeve.
  • the scraped developer is mixed and stirred with the toner appropriately supplied from the hopper 11 located above and the developer falling from the guiding mechanism 9 with rotation of the stirring vanes 7 in a direction of arrow 17, and the developer is delivered to a developer pump-up position 16.
  • the developer is magnetically attracted onto the sleeve 6 again and is delivered along the lower face of the guiding mechanism 9 with rotation of the sleeve 6.
  • the amount of the developer is controfled to a predetermined constant amount by the earing plate 12, and a part of the developer is delivered as the magnetic brush 13 to the developing zone 14 while the remaining portion of the developer is moved along the upper face of the guiding mechanism 9 and is fed to the stirring roller 8 again.
  • a regular flow of the developer is formed in the developing apparatus of the present invention.
  • the present invention movement of the flow of the developer is smoothly performed and mixing and stirring can be accomplished at a high efficiency by this movement. Furthermore, sufficient charges can be given even to the newly supplied toner and uniform mixing can be attained.
  • the present invention has various structural features for attaining these effects.
  • the developing apparatus of the present invention is characterized in that scraping of the developer present on the sleeve 6 and stirring of the developer are performed by using the stirring roller 8.
  • the stirring vanes 7 are formed on the stirring roller 8 so that a certain space is formed between the top ends of the stirring vanes 7 and the sleeve 6, and because of the presence of this space, the developer on the sleeve 6 is not completely scraped. Since only the toner present in the surface portion of the magnetic brush is consumed for the development, it is sufficient if scraping is performed so that this surface portion is scraped. For this reason, the above-mentioned space is formed between the top ends of the stirring vanes 7 and the sleeve 6. Furthermore, if this structure is adopted, the rotation torque of the stirring roller 8 is reduced and the rotation can be performed smoothly.
  • a scraping roller 25 is arranged in the lower portion of the space between the sleeve 6 and stirring vanes 7 adjacent to the sleeve 6.
  • the scraping roller 25 preferably comprises a linear plate vane 22 having a central axis 21 and a plurality of oval vanes 23 arranged at predetermined intervals on both the sides of the plate vane 22 in the state oriented in a certain direction. In this embodiment, there can be attained not only an effect of scraping the developer but also an effect of mixing and stirring the developer.
  • the developer is scraped from the surface of the sleeve 6 by the plate vane 22 or oval vanes 23, and simultaneously, the developer is forcibly discharged in the orienting direction of the oval vanes 23 toward the stirring roller 8. Accordingly, as compared with the case where a plate-like scraper is formed to abut against the surface of the sleeve, in the present case the developer can be scraped, mixed and stirred more smoothly and effectively in the state where the scraper is buried in the developer.
  • a spiral roller 25' having a spiral vane 26 is disposed instead of the scraper roller 25. Also in this case, the scraping effect and the mixing and stirring effect can be similarly attained.
  • the top end portions of the stirring vanes 7 arranged on the stirring roller 8 are bent in the rotation direction to enhance the effect of scraping the developer on the sleeve 6.
  • a developer delivery space 30 is formed between every two adjacent stirring vanes 7, and notches 31 are formed on the respective stirring vanes 7 so that the notches 31 are gradually deviated in the lateral direction in the respective stirring vanes 7, whereby a spiral passage 32 extending along the deviation direction is formed on the peripheral face of the stirring roller 8.
  • the developer is moved in the above-mentioned developer delivery spaces with rotation of the stirring vanes 7 and the developer is delivered in the direction of arrow 32 with rotation of the stirring roller 8 in the direction of arrow 17. Therefore, by using the stirring roller 8 having the above-mentioned structure, not only scraping of the developer from the sleeve 6 but also mixing of the developer can be performed effectively.
  • the second characteristic feature of the present invention is that the developer flow guiding mechanism 9 is arranged above the stirring roller 8 and the developer removed from the sleeve 6 by the earing blade 12 is smoothly supplied onto the stirring roller 8 again.
  • a definite flow of the developer is established as indicated by arrow P in Fig. 1, and scraping of the developer and mixing and stirring of the developer can be performed smoothly and effectively.
  • this developer flow guiding mechanism 9 comprises a partition plate 43 arranged on the upper side of the stirring roller 8 and guide plates 44 arranged on the top face of the partition plate 43 at predetermined intervals (for example, about 20 mm). Namely, the developer removed from the sleeve 6 by the earing plate 12 is passed through the top face of the partition plate 43 and directed onto the stirring roller 8 by the guide plates 44.
  • FIG. 5 One modification 9' of this developer flow guiding mechanism 9 is shown in Fig. 5, and by using this guiding mechanism 9', the effect of mixing and stirring the developer is further enhanced.
  • guide plates 44a and 44b are arranged on the upper and lower faces of the partition plate 43, respectively.
  • the guide plates 44a formed on the upper face are arranged in parallel to each other and have an acute angle to the axis of the stirring roller 8
  • the guide plates 44b formed on the lower face are arranged in parallel to each other and have an obtuse angle to the axis of the stirring roller 8.
  • the developer delivered by the stirring roller 8 and pumped up onto the sleeve 6 is moved as indicated by arrow 45 from the lower face of the partition plate 43 to the upper face of the partition plate 43. Accordingly, the direction of the movement of the developer on the partition plate 43 is, as a whole, reverse to the direction of the movement of the developer in the developer delivery space 30 in the stirring roller 8. Therefore, by combining this developer flow guiding mechanism 9' with the stirring roller 8, the effect of mixing and stirring the developer can be further increased.
  • Figs. 6 and 7. are different from each other only in the shape of the scraping roller 25.
  • a plate-like scraping roller 25 (see Fig. 6) or a spiral scraping roller 25' (see Fig. 7) is arranged as the scraping roller 25, and the scraping roller 25 or 25' is combined with the developer flow guiding mechanism 9' shown in Fig. 5.
  • it is important that the extending direction of vanes of the scraping roller 25 or 25' or the rotating direction thereof should be determined so that the direction of the movement of the developer by the scraping roller 25 or 25' is reverse to the direction of the movement of the developer by the stirring roller 8. Namely, if the above-mentioned extending direction or rotation direction is the same as the moving direction of the developer, the effect of mixing and stirring the developer is reduced.
  • the wall surface 20' of the housing 20 on the side opposite to the side where the sleeve 6 is located be inclined toward the stirring roller 8. If this arrangement is adopted, the delivery and circulation of the developer can be performed at a high efficiency. It is preferred that this wall surface 20' be curved along the loci of the top ends of the stirring vanes 7, and be inclined at a certain angle a, for example, 3 to 40°, especially 5 to 20°, from a vertical plane. It also is preferred that the distance I between the curved portion of the wall surface 20' and the top end of the stirring vane 7 be within 5 mm. According to this preferred embodiment, the delivery, mixing and stirring of the developer can be performed smoothly and effectively, without the developer staying unreasonably long in the developing apparatus.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Dry Development In Electrophotography (AREA)
EP19850302499 1984-05-16 1985-04-09 Developing apparatus Expired EP0161795B1 (en)

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
JP72528/84U 1984-05-16
JP7252884U JPS60184068U (ja) 1984-05-16 1984-05-16 二成分系現像装置の攪拌ローラ
JP72529/84U 1984-05-16
JP7252984U JPS60184069U (ja) 1984-05-16 1984-05-16 電子写真用現像装置
JP72527/84U 1984-05-16
JP7252784U JPS60184067U (ja) 1984-05-16 1984-05-16 現像装置

Publications (2)

Publication Number Publication Date
EP0161795A1 EP0161795A1 (en) 1985-11-21
EP0161795B1 true EP0161795B1 (en) 1988-01-13

Family

ID=27300983

Family Applications (1)

Application Number Title Priority Date Filing Date
EP19850302499 Expired EP0161795B1 (en) 1984-05-16 1985-04-09 Developing apparatus

Country Status (2)

Country Link
EP (1) EP0161795B1 (fi)
DE (1) DE3561423D1 (fi)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4878088A (en) * 1985-07-02 1989-10-31 Fujitsu Limited Developing unit of electrophotographic apparatus
DE69019113T2 (de) * 1989-11-29 1995-10-12 Mita Industrial Co Ltd Zuführrolle zum Mischen eines Pulvers.
US5249019A (en) * 1989-11-29 1993-09-28 Mita Industrial Co., Ltd. Feed roller for mixing and feeding a powder

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3911864A (en) * 1973-01-17 1975-10-14 Xerox Corp Toner preloaded magnetic brush development system
US3882823A (en) * 1973-08-15 1975-05-13 Minolta Camera Kk Stirring and scraping device for developing material
US3970036A (en) * 1974-07-17 1976-07-20 Savin Business Machines Corporation Toner concentration detector for dry powder magnetic brush toning system
JPS52125339A (en) * 1976-04-14 1977-10-21 Hitachi Ltd Detector for toner density

Also Published As

Publication number Publication date
EP0161795A1 (en) 1985-11-21
DE3561423T (fi) 1988-02-18
DE3561423D1 (en) 1988-02-18

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