EP0699976B1 - Recycle developing process - Google Patents

Recycle developing process Download PDF

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Publication number
EP0699976B1
EP0699976B1 EP95305938A EP95305938A EP0699976B1 EP 0699976 B1 EP0699976 B1 EP 0699976B1 EP 95305938 A EP95305938 A EP 95305938A EP 95305938 A EP95305938 A EP 95305938A EP 0699976 B1 EP0699976 B1 EP 0699976B1
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EP
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Prior art keywords
toner
virgin
developing
developer
flowability
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Expired - Lifetime
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EP95305938A
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German (de)
English (en)
French (fr)
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EP0699976A1 (en
Inventor
Masahide c/o Mita Industrial Co. Ltd. Inoue
Takeshi c/o Mita Industrial Co. Ltd. Arakawa
Yutaka c/o Mita Industrial Co. Ltd. Aso
Ryo c/o Mita Industrial Co. Ltd. Fujisawa
Mamoru c/o Mita Industrial Co. Ltd. Kato
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Kyocera Mita Industrial Co Ltd
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Mita Industrial Co Ltd
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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G21/00—Arrangements not provided for by groups G03G13/00 - G03G19/00, e.g. cleaning, elimination of residual charge
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03G—ELECTROGRAPHY; ELECTROPHOTOGRAPHY; MAGNETOGRAPHY
    • G03G21/00—Arrangements not provided for by groups G03G13/00 - G03G19/00, e.g. cleaning, elimination of residual charge
    • G03G21/10—Collecting or recycling waste developer

Definitions

  • This invention relates to a recycle developing process used in an electrophotographic apparatus such as a copying machine or a printer.
  • image formation in electrophotography is carried out by charging (main charging) the surface of a photosensitive material, imagewise exposing the charged material to form an electrostatic image on the surface of the photosensitive material, developing the image with a developer filled in a developing vessel to form a visualized toner image, transferring the toner image to a predetermined paper, and removing the toner remaining on the photosensitive material after the transferring by using a device such as a cleaning blade to complete one cycle of image forming step.
  • a typical developer is, for example, a two-component magnetic developer composed of an electroscopic toner made of a colored resin composition and a magnetic carrier.
  • the developer is delivered to a developing zone in the form of a magnetic brush by means of a developer conveying sleeve provided in a developing vessel, sliding the magnetic brush with the electrostatic image on the photosensitive material, and adhering the toner to the electrostatic image to thereby perform development.
  • the surface of the toner is surface-treated with a treating agent such as silica or alumina so that its properties such as flowability may be held stably.
  • a treating agent such as silica or alumina
  • the toner which is supplied for development is adhered to the surface of the photosensitive material and thereafter is recovered by cleaning, the surface treating agent is removed or embedded in the toner particles due to an external force of cleaning or to a force exerted after recovering in the step of conveying into the developing vessel.
  • the toner has an extremely decreased flowability. Accordingly, as the recovered toner is replenished into the developing vessel, the flowability of the developer decreases.
  • the toner in the developer contained in the developing vessel all becomes a recovered toner, and the properties of the toner become very much different from the initial developing agent, and it becomes difficult to perform development stably.
  • a toner concentration sensor is provided so that the toner concentration (T/D) of a developer composed of a toner and a carrier may be controlled within a predetermined range. Controlling of this toner concentration is carried out by utilizing the variation of the toner concentration in the developer corresponding to the permeability of the developer. The permeability of the developer is detected by the toner concentration sensor and the toner is replenished into the developing vessel according to the output value of the sensor.
  • curve A in Fig. 3 shows the relation between the output (corresponding to the permeability of the developer) of the concentration sensor in the starting developer and the toner concentration (T/D).
  • the threshold value of ON-OFF of toner replenishing is set at a sensor output value 3V
  • the toner is replenished to the developing vessel when the toner concentration becomes 3.5 % or below.
  • the properties vary and the relation between the output of the concentration sensor and the toner concentration changes to, for example, curve B. Therefore, by the above-mentioned setting of the threshold value, it will become difficult to maintain the toner concentration at a predetermined level.
  • a recycle developing process which comprises developing an electrostatic image formed on a photosensitive material with a starting developer composed of an electroscopic toner and a magnetic carrier filled in a developing vessel to form a toner image, transferring the toner image to a predetermined paper, recovering the toner remaining on the photosensitive material by a cleaning means, and repeatedly performing development while replenishing a virgin toner and the toner recovered by the cleaning means into the developing vessel; wherein the virgin toner to be replenished into the developing vessel has a flowability of 50 to 70 % based on that of the toner in the starting developer, the flowability being shown as a toner falling amount that is measured by filling the toner in the container in which a rotating roller is provided in an opening portion at a lower portion and falling the toner via the rotating roller for a certain fixed time.
  • the toner concentration of the developer in the developing vessel it is preferred to detect the toner concentration of the developer in the developing vessel and replenishing the virgin toner into the developing vessel based on the detected value. Especially, it is desirable to vary the detected value of the sensor, which becomes the threshold value of ON-OFF control of the supply of the virgin toner, depending upon the action time of an image forming cycle.
  • Fig. 1 is a view showing one example of an electrophotographic apparatus for conveniently practicing the recycle developing process of this invention.
  • Fig. 2 is a view showing principal parts of a developing apparatus used in Fig. 1.
  • Fig. 3 is a diagram showing the relation between the output of a toner concentration sensor and the toner concentration.
  • Fig. 4 is a view showing a tester for measuring the falling amount of a toner.
  • Fig. 5 is a view showing variations of the threshold value of the output of a toner concentration sensor for performing ON-OFF control of the supply of the toner in an experiment of an Example.
  • the virgin toner to be replenished into the developing vessel which has a lower flowability than the toner in the starting developer, is used whereby an abrupt decrease in the properties of the developer due to the use of the recovered toner is suppressed, and the development can be carried out stably even if the recovered toner is used.
  • the decrease in the properties of the developer due to the mixing of the recovered toner is relaxed by the replenishing of the virgin toner.
  • the flowability of the toner is shown as the amount of the toner which falls, when the toner filled in a container in which a rotating roller is provided in an opening portion at a lower portion, via the rotating roller for a certain period of time.
  • a fixed amount of the toner is filled in a container 51 (taper angle 60 degrees) in which a rotating roller 50 is provided in an opening portion at a lower portion, and by rotating the rotating roller 50 at a fixed speed, the toner is fallen to a receiver 52 at a lower portion.
  • the falling amount of the toner is measured. This falling amount becomes an index showing flowability. Accordingly, as the falling amount is larger, the flowability is higher.
  • the measurement of the falling amount of the toner is carried out by using a brass rotating roller 50 having a diameter of 20 mm, filling 20 g of the toner in the container 51, prescribing the rotating number of the rotating roller 50 at 3 rpm, and falling the toner over the course of 5 minutes.
  • the flowability of the virgin toner to be replenished (the above-mentioned falling amount of the toner) is adjusted to 50 to 70 %, preferably 55 to 65 %, of the toner in the starting developer. if the flowability is higher than the above-mentioned range, the supply of the recovered toner markedly lowers the properties of the toner, especially its flowability. Thus, the development cannot be carried out stably, and for example, inconveniences such as toner scattering and fogging occur in the formed image.
  • the adjustment of the flowability of the toner can be performed by adjusting the amount or particle diameter of the surface treating agent to be outwardly sprinkled on the surface of the toner.
  • the threshold value may be varied according to the integrated value of the driving time of a driving motor for the sleeve.
  • a main charging device 2 an optical system 3
  • a developing apparatus 4 a transferring charging device 5 and a cleaning apparatus 6 such as a cleaning blade are sequentially provided around a photosensitive drum 1.
  • a fixing apparatus 7 is provided adjacently to the photosensitive drum 1.
  • the surface of the photosensitive drum 1 is charged by the main charging apparatus 2, and imagewise exposed by the optical system 3 to form an electrostatic image on the photosensitive drum 1.
  • This electrostatic image is then developed by the developing apparatus 4 to form a visualized toner image, and is transferred to a predetermined paper 8 by the transferring charging device 5.
  • the paper 8 bearing the transferred toner image is introduced into the fixing apparatus 7 and the toner image is fixed with heat, pressure, etc.
  • the toner remaining on the photosensitive drum 1 after transferring is removed from the surface of the photosensitive drum 1 by the cleaning apparatus 6, and recovered. In this way, one step of image forming cycle is completed.
  • the above developing apparatus 4 is provided with a developer conveying sleeve 10 having a magnet inside and a developing vessel 11. A developer is filled inside in the developing vessel 11. This developer is conveyed by the sleeve 11 in the form of a magnetic brush, this magnetic brush is abraded by the surface of the photosensitive drum 1, and a charging toner adheres to the electrostatic image to form a toner image.
  • FIG. 2 The structure of this developing apparatus 3 is shown in Fig. 2.
  • the developing vessel 11 is partitioned into two chambers 4a and 4b by a partitioning wall 20, and spirals 21 and 22 are provided in each of the chamber.
  • a toner concentration sensor 23 is provided in the partitioning wall 20.
  • one chamber 4b communicates with a toner replenishing hopper 25 including a spiral 24.
  • a toner tank 26 filled with a replenishing virgin toner is provided at an upper portion of this hopper 25, a toner tank 26 filled with a replenishing virgin toner is provided.
  • the virgin toner in the toner tank 26 is fed into the inside of the hopper 25, and replenished into the inside of the chamber 4b of the developing vessel 11 by the spiral 24.
  • the virgin toner replenished into the inside of the chamber 4b is reciprocated between the chambers 4b and 4a by the spirals 22 and 21, mixed with the developer already existing within the developing vessel 11, and fed from the chamber 4a to the sleeve 10 and used for development.
  • the sleeve 10 is driven and rotated by a motor 50 and the spiral 24 within the hopper 25 is driven and rotated by a motor 27 which is driven independently from the motor 50.
  • the motor 27 is ON-OFF controlled by the detected output of the toner concentration sensor 23.
  • a recovered toner reserving tank 30 On the other hand, a recovered toner reserving tank 30.
  • the toner recovered by the cleaning apparatus 6 is accommodated temporarily within the reserving tank 30 by natural falling or suctioning.
  • a spiral 31 is provided at a bottom portion of the reserving tank 30, and its forward end extends to the inside of the hopper 25.
  • a paddle 32 is provided in its forward end portion, and this paddle 32 adjoins the spiral 24. The recovered toner is sent into the inside of the hopper 25 by the spiral 31 and the paddle 32, mixed with the replenishing virgin toner with stirring, and replenished with the virgin toner into the developing vessel 11 so that the mixture will be use for development.
  • the spiral 31 and the paddle 32 may be driven as an integral unit with the sleeve 10 by a driving transmission means (for example, such as a worm and a gear) linked to the driving motor 50 of the sleeve 10.
  • a driving transmission means for example, such as a worm and a gear
  • the replenishing virgin toner as already stated above, is mixed in advance with the recovered toner, and the mixture is then replenished into the developing vessel 11.
  • the timing of this replenishing is when the toner concentration of the developing vessel 11 reaches a certain fixed value or below.
  • the motor 27 is driven for a fixed period of time, and the spiral 24 in the hopper 25 operates to supply the virgin toner into the developing vessel 11.
  • the toner recovered by the cleaning apparatus 6 is accommodated in the reserving tank 30, and simultaneously with the driving of the sleeve 10, the recovered toner is sent into the hopper 25 by the spiral 31 and the paddle 32 driven during the developing operation and is mixed with the virgin toner in the hopper 25 with stirring. Accordingly, the recovered toner is replenished with the virgin toner into the developing vessel 11 and the mixture is used for development.
  • the threshold value of ON-OFF of the replenishing of the toner into the above-mentioned developing vessel 11 is preferably prescribed and varied according to a copying time, for example, the integrated value of the driving time of the motor 50 driving the sleeve 10. In other words, every time that the integrated value of the driving time of the motor 50 becomes a predetermined period of time, the threshold value of ON-OFF is prescribed. In this way, the recovered toner is replenished into the developing vessel 11, and even if a change in the properties of the developer occurs, unless the change if the properties is abrupt, it is possible to adjust the toner always to a fixed toner concentration.
  • the photosensitive drum 1 may be any known photosensitive material such as organic photosensitive materials, amorphous selenium and amorphous silicon. Generally, the organic photosensitive materials are preferred from the viewpoint of cost.
  • two-component type magnetic developers composed of a toner and a magnetic carrier are used as the developer.
  • a replenishing virgin toner is used as a toner having lower flowability than the toner in the starting developer used at the time of starting.
  • the toner in the starting developer may be a known toner prepared by dispersing toner compounding agents such as a colored pigment, a charging controlling agent, and a mold releasing agent in a fixing resin, and surface-treating the mixture with a flowability increasing agent.
  • the fixing resin examples include those containing fixability and electroscopic property, specifically styrene-type resins, styrene/acrylic resins, polyester resins, polyurethane resins, silicone resins, polyamide resins and modified rosins.
  • the styrene-acrylic resins are used.
  • the colored pigments are used usually in an amount of 2 to 20 parts by weight, especially 5 to 15 parts by weight, per 100 parts by weight of a fixing resin medium. Suitable examples are listed below.
  • Carbon black, acetylene black, lamp black and aniline black Carbon black, acetylene black, lamp black and aniline black.
  • Zinc white, titanium oxide, antimony white and zinc sulfide Zinc white, titanium oxide, antimony white and zinc sulfide.
  • Examples of the charge controlling agent include oil-soluble dyes such as Nigrosin Base (C. I. 50415) and spiron black, metal-containing azo dyes, metal salts of naphthenic acid, metal salts of alkylsalycylic acids, fatty acid soaps, and resin acid soaps.
  • the compounding amounts of these charge controlling agents are usually 0.1 to 10 parts by weight, especially 0.5 to 5 parts by weight, per 100 parts by weight of the fixing resin.
  • a mold releasing agent is compounded in order to apply mold releasability at the time of heat fixation.
  • examples of such a mold releasing agent include usually polyolefin resins, especially low-molecular-weight polypropylene.
  • the amount of the mold releasing agent is usually 0.1 to 6 parts by weight per 100 parts by weight of the fixing resin medium.
  • the toner particles prepared by dispersing the toner compounding agent in the fixing resin can be produced by a known method such as a pulverization and classifying method, a melting granulating method, a spray granulating method, and a polymerization method.
  • a pulverization and classifying method is generally used.
  • the individual toner components are pre-mixed in a mixer such as a Henschel mixer, the mixture is kneaded by using a kneader such as a biaxial extruder, the kneaded composition is cooled, pulverized and classified to form a toner.
  • the particle diameter of the toner is a median diameter, measured by a Coulter counter, of 5 to 15 ⁇ m, especially 7 to 12 ⁇ m.
  • a flowability improver is adhered to the surface of the toner particles byoutward sprinkling and surface-treating the toner to thereby improve its flowability.
  • Examples of such a flowability improver are resin powders such as a fine powder of silica powder or an acrylic powder having a particle diameter of 0.005 to 0.05 ⁇ m, and hydrophobic gaseous phase method silica surface-treated with an organopolysiloxane or silazan.
  • the amount of flowability improver may be 0.1 to 2.0 % by weight based on the toner.
  • the transfer efficiency may be increased by adding such a flowability improver and spacer particles with a particle diameter of 0.05 to 1.0 ⁇ m and having a larger particle diameter than the flowability improver.
  • a flowability improver and spacer particles with a particle diameter of 0.05 to 1.0 ⁇ m and having a larger particle diameter than the flowability improver.
  • the spacer particles may be any organic or inorganic inert regular shaped particles having the above-mentioned particle diameter.
  • magnetic powders, alumina, etc. may be used.
  • Such spacer particles may be sprinkled on the surface of the toner in an amount of 0.1 to 1.5 % by weight, especially 0.2 to 1.0 % by weight, per the toner.
  • Suitable examples of the magnetic powders may include the following compounds. Tri-iron tetroxide (Fe3O4), iron-sesquioxide ( ⁇ -Fe2O3), zinc iron oxide (ZnFe3O4), yttrium iron oxide (Y3Fe5O12), cadmium iron oxide (CdFe2O4), gadolium iron oxide (Gd3Fe5O12), copper iron oxide (CuFe2O4), lead iron oxide (PbFe12O19), nickel iron oxide (NiFe2O4), neodymium iron oxide (NdFePO3), barium iron oxide (BaFe12019), magnesium iron oxide (MgFe204), manganese iron oxide (MnFe2O4), lanthanum iron oxide (LaFeO3), iron powder (Fe), cobalt powder (Co), and nickel powder (Ni).
  • Tri-iron tetroxide Fe3O4
  • iron-sesquioxide ⁇ -Fe2O3
  • the magnetite (tri-iron tetroxide) is especially preferred.
  • the flowability improver and the spacer particles are mixed in advance intimately, the mixture is added to the toner, and the entire mixture is fully pulverized.
  • the toner for the starting developer so prepared has a toner falling amount, measured under the above-mentioned conditions, of usually 3.5 to 8.0 g/5 minutes, especially 4.5 to 6.5 g/5 minutes.
  • a known material such as ferrite or iron powder may be used as the magnetic carrier to be used as mixed with the above-mentioned toner. Its particle diameter is usually 50 to 120 ⁇ m, especially 85 to 105 ⁇ m.
  • the mixing ratio between the magnetic carrier and the toner is preferably 98 : 2 to 90 :10 by weight, especially 97 : 3 to 92 : 8 by weight.
  • the virgin toner to be replenished corresponding to the consumption of the toner by the development has the same composition as the toner of the starting developer except that the toner falling amount, showing its flowability, is prescribed at 50 to 70 %, especially 55 to 65 %, based on the toner of the starting developer.
  • the toner falling amount may be easily adjusted by adjusting the amount and the particle diameter of the surface-treating agent.
  • the amount of the surface-treating agent such as the flowability improver or the spacer particles, especially the amount of the flowability improver, is made larger, the amount of the toner falling becomes larger.
  • the amount of the surface-treating agent is made smaller, the amount of the toner falling becomes smaller.
  • the particle diameter of the surface-treating agent is smaller, the toner falling amount becomes larger, and when the particle diameter of the surface-treating agent is larger, the toner falling amount becomes smaller.
  • Such a replenishing virgin toner may usually be mixed with 100 to 300 parts by weight of the recovered toner per 100 parts by weight of the recovered toner.
  • the replenishing virgin toner by decreasing the flowability of the replenishing virgin toner as compared with the toner of the starting developer, it is possible to suppress an abrupt lowering in the properties of the developer of the developer by the mixing of the recovered toner.
  • the threshold value of ON-OFF of supplying the replenishing toner it is possible to maintain the toner concentration always at a fixed value, and development can be stably performed.
  • the individual agents mentioned below were melt kneaded by a biaxial extruder.
  • the resulting kneaded mixture was pulverized by a jet mill, and classified by a wind-powered classifier to give toner particles having an average particle diameter of 10.0 ⁇ m.
  • Alumina made by Sumitomo Chemical Co., Ltd. under the tradname of AKP-20 having a central particle diameter of 0.5 ⁇ m and a hydrophobic silica powder (made by Cabbot Co., Ltd. under the tradename of TS-720) having a particle diameter of 0.015 ⁇ m were mixed for 1 minute by using a vita mix in a weight ratio of 10 : 1 to give an alumina-pretreated agent.
  • Magnetite (made by Titanium Industry Co., Ltd. under the tradename of BR-220) having a saturated magnetization of 83 emu/g and a central particle diameter of 0.3 ⁇ m and the above-mentioned hydrophilic silica powder were mixed for 1 minute by using a vita mix in a weight ratio of 10 : 1 to give a magnetite-pretreated agent.
  • the magnetite-pretreated agent (0.25 % by weight) was added to the the prepared toner particles, and they were mixed for 2 minutes by a Henschel mixer to give a magnetite-treated toner. Then, 0.3 % by weight of the hydrophobic silica powder used in the preparation of the above-mentioned surface-treating agent was added to the magnetite-treated toner. They were mixed for 2 minutes by a Henschel mixer to prepare a toner for the starting toner. By using the apparatus shown in Fig. 4, the falling amount of the toner under the conditions shown in the specification was measured. The results are shown in Table 1.
  • This toner for the starting developer and a ferrite carrier (Powder Tech Co., Ltd. under the tradename of FL184-150) having an average particle diameter of 80 ⁇ m were mixed by a ball mill at 75 rpm for 2 hours to give a starting developer having a toner concentration of 4.5 %.
  • the above-mentioned alumina-pretreated agent (1.0 % by weight) was mixed with the toner particles prepared above by a Henschel mixer for 2 minutes to prepare an alumina-treated toner. Thereafter, 0.3 % by weight of the hydrophobic silica powder used in the above-mentioned preparation of the above-mentioned surface treating agent was added to this alumina-treated toner. They were mixed for 2 minutes by a Henschel mixer to prepare a replenishing virgin toner. The falling amount of this toner was measured. The results are shown in Table 1.
  • a copying machine DC-2556 made by Mita Industrial Co., Ltd. using an organic photosensitive material was remodelled into a recycle-type machine shown in Fig. 4.
  • continuous copying was performed through 30,000 sheets under the following conditions, and T/D controllability, fogging and toner scattering were evaluated. The results are shown in Table 1.
  • the virgin toner was mixed with the recovered toner in an amount of 100 to 300 parts by weight per 100 parts by weight of the recovered toner, and the mixture was replenished.
  • the toner concentration was controlled by varying the threshold value of ON-OFF control of supplying the toner by the output of the sensor in accordance with the flow chart shown in Fig. 5.
  • test items were evaluated in the following manners.
  • the evaluation was shown as ⁇ , and even when by adjusting the variations of the threshold value, the toner concentration could not be stabilized at 3.8 %, the evaluation was show as X.
  • Fogging densities at the first sheet (early period), 15,000th sheet and 30,000th sheet were shown.
  • Alumina-pretreated agent Alumina (made by Sumitomo Chemical Co., Ltd. under a tradename of AKP-50) having a central particle diameter of 0.2 ⁇ m was mixed with the hydrophobic silica powder (having a central particle diameter of 0.015 ⁇ m) used in Example 1 for 1 minute by a vita mix in a weight ratio of 10 : 1 to prepare an alumina-pretreated agent.
  • Example 1 a replenishing virgin toner was prepared except that the alumina-pretreated agent prepared above was added to the toner particles prepared in Example 1 (1.0 % by weight of the alumina-pretreated agent). The fallen amount of the toner was measured, and the results are shown in Table 1.
  • Example 1 The hydrophobic silica powder (0.3 % by weight) used in Example 1 was added to the toner particles prepared in Example 1. They were mixed for 2 minutes by a Henschel mixer to prepare a toner for the starting developer. The fallen amount of the toner was measured, and the results are shown in Table 1.
  • a starting developer having a toner concentration of 3.5 % was prepared in the same way as in Example 1 except that the above toner for the starting developer was used.
  • An acrylic fine powder having a central particle diameter of 0.25 ⁇ m was added in an amount of 0.5 % by weight to the toner particles prepared in Example 1 to obtain an acrylic powder-treated toner.
  • a replenishing virgin toner was prepared in the same way as in Example 1 except that this acrylic powder-treated toner was used. The falling amount of the toner was measured, and the results are shown in Table 1.
  • Example 1 Using the above-mentioned starting developer and the replenishing virgin toner, the same experiment as in Example 1 was carried out. The results are shown in Table 1.
  • Example 1 Using the same starting toner prepared in Example 1, the same toner as in the starting developer was used as the replenishing virgin toner. Otherwise, the same experiment as in Example 1 was carried out. The results are shown in Table 1.
  • An acrylic fine powder having a central particle diameter of 0.5 ⁇ m was added in an amount of 1.0 % by weight to the toner particles prepared in Example 1 to obtain an acrylic powder-treated toner.
  • a replenishing virgin toner was prepared in the same way as in Example 1 except that this acrylic powder-treated toner was used. The falling amount of the toner was measured, and the results are shown in Table 1.
  • Example 1 The same experiment as in Example 1 was carried out except that the above-mentioned replenishing virgin toner was used. The results are shown in Table 1.
  • Example 1 The hydrophobic silica fine powder used in Example 1 was added in an amount of 0.1 % by weight to the toner particles prepared in Example 1. They were mixed for 2 minutes by a Henschel mixer to prepare a replenishing virgin toner. The falling amount of the toner was measured, and the results are shown in Table 1.
  • Example 3 The same experiment as in Example 3 was carried out except that the above-mentioned replenishing virgin toner was used. The results are shown in Table 1.
  • a replenishing virgin toner having a toner falling amount of 50 to 70 % as compared with the toner of the starting developer is used, whereby an abrupt decrease in the properties of the developer due to the mixing of the toner can be relaxed.
  • a stable image free from fogging or toner scattering can be formed by the recycle developing process.

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  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Life Sciences & Earth Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Environmental & Geological Engineering (AREA)
  • Sustainable Development (AREA)
  • Developing Agents For Electrophotography (AREA)
  • Cleaning In Electrography (AREA)
  • Dry Development In Electrophotography (AREA)
EP95305938A 1994-08-29 1995-08-24 Recycle developing process Expired - Lifetime EP0699976B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP203261/94 1994-08-29
JP06203261A JP3110621B2 (ja) 1994-08-29 1994-08-29 リサイクル現像方法

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EP0699976A1 EP0699976A1 (en) 1996-03-06
EP0699976B1 true EP0699976B1 (en) 1998-12-23

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DE (1) DE69506811T2 (ja)

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CN104849971A (zh) * 2015-05-28 2015-08-19 湖北鼎龙化学股份有限公司 彩色调色剂及其制备方法、以及调色剂颗粒流动性的测试方法

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US4894688A (en) * 1987-03-03 1990-01-16 Mita Industrial Co., Ltd. Device for circulating developer
EP0431930B1 (en) * 1989-12-08 1996-10-23 Sharp Kabushiki Kaisha Developer for electrophotography
JP2953001B2 (ja) * 1990-08-28 1999-09-27 ミノルタ株式会社 トナー供給装置
JP2726154B2 (ja) * 1990-11-30 1998-03-11 三田工業株式会社 電子写真用磁性現像剤
JPH04204962A (ja) * 1990-11-30 1992-07-27 Konica Corp 現像剤層の形成方法

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KR960008453A (ko) 1996-03-22
DE69506811T2 (de) 1999-08-05
EP0699976A1 (en) 1996-03-06
JP3110621B2 (ja) 2000-11-20
JPH0869177A (ja) 1996-03-12
DE69506811D1 (de) 1999-02-04

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