JP2726278B2 - Electrophotographic copying machine - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic copying machine (including an electrostatic copying machine), and more particularly, to a photoconductor (including an electrostatic recording body) after transferring a toner image onto plain paper or the like. The present invention relates to an electrophotographic copying apparatus in which a magnetic brush cleaning device is provided in a cleaning section for removing residual toner on the surface.

(Prior art)

As shown in FIG. 1, the electrophotographic copying apparatus roughly includes an organic or inorganic photoreceptor 1 (which may be a belt-shaped member instead of a drum-shaped member) and a charger 2 and an optical system 3 around the photosensitive member. , A developing unit 4, a transfer charger 5, a separation charger 6, and a cleaning unit 7. The transfer charger 5 is used to transfer the toner image on the photoconductor 1 to transfer paper 8 such as plain paper, and the separation charger 6 transfers the transfer paper 8 having the toner image to the photoconductor 1.
It is used to separate it from the surface. In the drawings, reference numeral 9 denotes a separation claw.

Either a dry developing method or a wet developing method (including a semi-dry developing method) is employed for visualizing an electrostatic charge image. The former is advantageous in that a copy can be obtained in a dry state. Therefore, the dry development method is now mainstream.

Dry development systems are broadly classified into those using a one-component type developer (composed of only a toner) and those using a two-component type developer (composed of a carrier and a toner). In any case, it is desirable that all the toner images visualized by such a developer are ideally transferred to transfer paper. However, since toner that cannot be completely transferred remains on the photoreceptor, this toner is used. Residual toner must be removed with a cleaning device.

Methods for cleaning residual toner (untransferred toner) include (1) fur brush, (2) blade, and (3)
It is common to use a magnetic brush or the like. But
The fur brush method requires a large cleaning device,
There is a dislike that filming easily occurs on the photoconductor. In addition, the blade method has a defect that the photosensitive member is easily damaged. On the other hand, cleaning by a magnetic brush method has been studied in, for example, Japanese Patent Application Laid-Open No. 58-102273. However, although the defects of the above (1) and (2) are eliminated, a conventional magnetic brush cleaning apparatus is used. However, there is a disadvantage that long-term cleaning is not guaranteed.

〔Purpose〕

SUMMARY OF THE INVENTION A first object of the present invention is to provide a magnetic brush cleaning unit using a two-component dry type developer, which can remove residual toner satisfactorily and can perform long-term cleaning. Is provided.
A second object of the present invention is to provide an electrophotographic copying apparatus capable of obtaining a large number of high quality copies.

〔Constitution〕

The present invention forms an electrostatic charge image on a photoreceptor, visualizes it with a two-component developer, transfers this toner image to transfer paper, and then removes the toner remaining on the photoreceptor surface with a magnetic brush cleaning unit. The carrier housed in the magnetic brush cleaning unit is an oxidized iron powder whose surface is coated with a low surface energy material in which a conductive material is dispersed. I have.

Incidentally, when the present inventors use a two-component developer, the carrier (cleaning agent) in the cleaning section
The surface of the magnetic brush is coated with a low surface energy material in which a conductive material is dispersed, so that the residual toner easily migrates to the carrier (cleaning carrier) of the magnetic brush cleaning unit. The toner easily separated from the cleaning carrier in the magnetic brush cleaning section, and as a result, it was confirmed that long-term cleaning could be performed. The present invention has been made based on such a thing.

In the following, the device according to the invention will be explained in more detail in connection with the copying process with reference to the accompanying drawing (FIG. 1).

First, the surface of a photoconductor (inorganic photoconductor, organic photoconductor) 1 is uniformly charged positively or negatively by a charger 2. Whether the positive charge is the negative charge or not is selected depending on the type (property) of the photoreceptor 1. For example, if the photoreceptor is of a Se type, the positive charge is performed. The image is exposed to the light by the optical system 3 to form an electrostatic image, and the electrostatic image is visualized by the developing unit 4.

The developing unit 4 contains a two-component developer composed of a carrier (magnetic carrier) and a toner. Developer is a magnet
The electrostatic image of the photoconductor 1 is developed by being held on a developing sleeve 41 having a built-in 411. Since only the developing toner is consumed each time the developing is performed, the sensor 42 detects the toner density of the developer and new developing toner is supplied so that the toner density always becomes constant. Reference numeral 43 denotes a paddle wheel for stirring the developer. Note that a bias may be applied to the developing sleeve 41 as needed.

The visible image (toner image) is transferred to the transfer paper 8 by the transfer charger 5, and the transfer paper 8 is separated from the photoreceptor 1 by the separation charger 6 and the separation claw 9 and sent to the fixing process.

As mentioned above, all of the toner that forms a visible image on the photoconductor 1 at the time of transfer is not transferred to the transfer paper 8, and part of the toner remains on the photoconductor 1. The residual toner is removed by the cleaning unit 7.

The cleaning unit 7 in the apparatus of the present invention employs a magnetic brush cleaning method, in which a magnetic carrier (cleaning carrier) as a cleaning agent is stored. A positive or negative bias of about 100 to 500 V is applied to the cleaning roller 71 having a magnet (not shown) built therein, and a cleaning agent is held on the cleaning roller 71 by the magnet. here,
The polarity of the bias applied to the cleaning roller 71 is opposite to the polarity of the toner in the two-component developer.

The residual toner is electrostatically attracted to a cleaning agent (cleaning carrier) and is transferred to the pumping rollers 72 to 73 together with the cleaning agent. A residual toner collecting roller 74 to which a bias having the same polarity as that of the cleaning roller 71 is applied is disposed behind the pumping roller 73, and only the residual toner is transferred to the collecting roller 74. The bias applied to the collection roller 74 is desirably relatively higher than the bias applied to the cleaning roller, and is suitably about 200 to 800 V.

Immediately after the residual toner is transferred from the pickup roller 73 to the collection roller 74, the cleaning carrier
The cleaning scraper 75 is scraped off by the cleaning scraper 75 and is returned to the surface of the cleaning roller 71 again. on the other hand,
The residual toner transferred to the collection roller 74 is scraped by a collection blade 76 in contact with the collection roller 74, taken out of the cleaning unit 7 by a discharge screw 74, and, if necessary, as a two-component developer toner. used. The collecting roller 74 cleaned by the collecting blade 76 is used for collecting the next remaining toner. The cleaning agent (cleaning carrier) that falls on the cleaning roller 71 and circulates again to contribute to the recovery of the residual toner is inevitably containing some residual toner. Is in the range of at most 2% by weight.

In the apparatus of the present invention, such a cycle of a series of copying and cleaning steps is repeated, but when the photoconductor 1 is uniformly charged by the charging charger 2, residual toner is present on the surface of the photoconductor. Therefore, uniform charging of the photoconductor 1 is assured.

The cleaning carrier (cleaning agent) used in the cleaning unit 7 is a low surface energy substance having a surface in which a conductive substance is dispersed (that is, a substance having excellent peelability).
As a result, it is possible to prevent the spent toner from adhering to the cleaning carrier, and as a result, the cleaning carrier has a constant charge amount (Q / M) over a long period of time. Is not caused, and the cleaning of the photoconductor 1 is performed satisfactorily.

In general, the cleaning carrier has a lower residual toner density than the developing carrier, and as described above, the cleaning
Since the toner is usually used in an amount of about 1% by weight (the toner concentration of the developing unit 4 is 2 to 7% by weight), the cleaning unit 7 has very many chances of friction between the cleaning carriers. It tends to adhere and the spent toner tends to adhere to the cleaning carrier. Therefore, in the case of a non-coated cleaning carrier, spent toner adheres to the carrier at an early stage, resulting in a decrease in Q / M and a remarkable reduction in image quality due to insufficient cleaning.

On the other hand, since the cleaning carrier according to the present invention has a surface coated with a material having good releasability, not only the inconvenience of the non-coated cleaning carrier does not occur but also the cleaning carrier (cleaning agent). The fluidity itself is also good, and the cleaning agent can move smoothly from the cleaning roller 71 to the pumping rollers 72, 73. Then, it is guaranteed that the toner is completely sent to the toner collecting roller 74, and good cleaning performance can be always maintained.

The cleaning agent (cleaning carrier) in the present invention has a form in which a carrier core material has a surface coated with a low surface energy substance in which a conductive substance is dispersed, and the core material here is oxidized iron powder. use. The particle size of the core material is suitably from 10 to 1000 μm, preferably from about 30 to 500 μm.

As the low surface energy substance covering the surface of the core material, a thermoplastic resin containing a polyolefin, for example, polyethylene, polypropylene, chlorinated polyethylene and chlorosulfonated polyethylene; polyvinyl and polyvinylidene, for example, polystyrene, polymethyl methacrylate, polyacrylonitrile , Polyvinyl acetate,
Polyvinyl alcohol, polyvinyl butyral, polyvinyl chloride, polyvinyl carbazole, polyvinyl ether and polyvinyl ketone; vinyl chloride-vinyl acetate copolymer, styrene-acrylic acid copolymer; silicone resin; fluorocarbon, polytetrafluoroethylene, polyvinyl fluoride, Polyvinylidene fluoride, polychlorotrifluoroethylene; polyamide resin; polyester (for example, polyethylene terephthalate); polyurethane; polycarbonate, amino resin (for example, urea-formaldehyde resin); and epoxy resin. Particularly preferred are silicone resins and fluorine-based resins.

The silicone resin here may be any conventionally known silicone resin, such as straight silicone consisting only of an organosiloxane bond, and a silicone resin modified with alkyd, polyester, epoxy, urethane, or the like.

(Wherein R ¹ is a hydrogen atom, an alkyl group or phenyl group having 1 to 4 carbon atoms, R ² and R ³ are a hydroxyl group, an alkyl group having 1 to 4 carbon atoms, an alkoxyl group having 1 to 4 carbon atoms, Phenyl group, phenoxy group, alkenyl group having 2 to 4 carbon atoms, alkenyloxy group having 2 to 4 carbon atoms, hydroxyl group, carboxyl group, ethylene oxide group, glycidyl group or R ⁴ and R ⁵ are a hydroxyl group, a carboxyl group,
An alkyl group having 1 to 4 carbon atoms, an alkoxyl group having 1 to 4 carbon atoms, an alkenyl group having 2 to 4 carbon atoms, an alkenyloxy group having 2 to 4 carbon atoms, a phenyl group, and a phenoxy group. k, l, m, n, o, and p represent an integer of 1 or more. Each of the above substituents may be unsubstituted, for example, amino group, hydroxyl group, carboxyl group, mercapto group,
It may have a substituent such as an alkyl group, a phenyl group, an ethylene oxide group, a glycidyl group and a halogen atom.

For example, straight silicone resins as commercially available products include KR271, KR255, KR251 manufactured by Shin-Etsu Chemical Co., Ltd., SR2400, SR2406 manufactured by Toray Silicon Co., Ltd. Acrylic modified), ES1001N (epoxy modified), SR2115 (epoxy modified), SR2110 (alkyd modified) manufactured by Toray Silicon Co., Ltd.

The fluororesin used here is polytetrafluoroethylene (PTFE), tetrafluoroethylene-hexafluoropropylene copolymer (FEP), polychlorotrifluoroethylene (PCTFE), polyvinylidene fluoride (PVDF), and tetrafluoroethylene. Examples include an ethylene-perfluoroalkyl vinyl ether copolymer (PFA),
In addition to these, those in which a filler is dispersed in a fluororesin can also be used.

In the present invention, in order to increase the cleaning electric field of the cleaning carrier and perform the cleaning satisfactorily, the conductive layer is formed in the surface layer of the cleaning agent (the surface layer made of a low surface energy substance such as the above-mentioned silicone resin and fluorine resin). The active substance is dispersed in an appropriate amount.

Examples of typical conductive substances (conductive materials)-white ones and carbon-are as follows (a) and (b).

(A) White conductive material ECT-52 (TiO ₂ system) KV400 (TiO ₂ system) manufactured by Titanium Industry Co., Ltd. ECR-72 (TiO ₂ system) manufactured by Titanium Industry Co., Ltd. ECTR-82 (TiO ₂ system) manufactured by Titanium Industry Co., Ltd. Titanium Industrial 500W (TiO ₂ type) Ishihara Sangyo 300W (TiO ₂ type) Ishihara Sangyo S-1 (TiO ₂ type) Ishihara Sangyo W-1 (SnO ₂ type) Mitsubishi Metal 23K (ZnO Hakusui Chemical Co., Ltd. Conductive zinc flower No.1 (ZnO) Honjo Chemical Co., Ltd. Conductive zinc flower No.2 (ZnO) Honjo Chemical Co., Ltd. W-10 (TiO ₂ system) Mitsubishi Metal Corporation Dentol WK-100 ( conductive fiber) manufactured by Otsuka Chemical Co. DENTALL WK-200 (conductive fiber) manufactured by Otsuka Chemical Co. DENTALL WK-300 (conductive fiber) manufactured by Otsuka Chemical Co. MEC300 (SnO ₂ system) Teikoku Kako Co. MEC500 (SnO ₂ type) Carbon black Pearls 200, VULCANXC-72 (manufactured by Cabot), manufactured by Teikoku Kakosha Co., Ltd. Ketjen black EC / DJ500, Ketjen black EC / DJ
600 (manufactured by Lion Akzo) Denka black granular, denka black powder (manufactured by Denki Kagaku Kogyo) CONDUCTEX975, CONDUCTEX SC (manufactured by Columbia Carbon) These conductive materials (conductive materials) have a particle size of 0.01 to 3 μm, preferably 0.05 to 2.0 μm is appropriate, and the amount of addition is 0.1 to 100 parts by weight of the low surface energy substance.
100 parts by weight, preferably 0.5 to 80 parts by weight, is suitable. These conductive materials may be used alone or in combination of two or more.

In the present invention, the Q / M value of the cleaning agent is increased immediately after the cleaning agent comes into contact with the toner (that is, the residual toner easily migrates to the cleaning agent immediately after the residual toner comes into contact with the cleaning agent). So that cleaning is better.
It is desirable that an appropriate amount of a triboelectric charge imparting substance is dispersed and contained in the low surface energy substance layer (coating layer) in which the conductive substance is dispersed.

For example, for a negatively charged toner, a substance having a positive chargeability is dispersed in the cleaning carrier coating layer, and for a positively chargeable toner, a substance having a negative chargeability is dispersed in the cleaning carrier coating layer. Disperse in. Examples of such a triboelectric charge-imparting substance include various dyes and pigments, and resins containing halogen, epoxy, hydroxyl, amino, phenyl, and carboxyl groups as functional groups; aliphatic metal salts; complex compounds; complex salts; salicylic acid Or a metal salt of a salicylic acid derivative,
Some of them are as follows.

(1) Nigrosine dye (especially CISo
lvent Black 5 and CISolvent Black 7 are better). Examples of CISolvent Black 5 include Orient Spirit Black AB (Orient Chemical) Orient Spirit Black SB (Orient Chemical) Spirit Black No350 (Sumitomo Chemical) Spirit Black No900 (Sumitomo Chemical) CISolvent Black 7 Examples include Nigrosine Base GB (Bayer) and Nigrosine Base Lk (BASF).

(2) Xanthene dyes (especially CI Pigment Red 81, CIS
What is included in olvent Red 49 is good. This is an example of CIPigment Red 81: Dainichi Fast Pink GX Toner (Dainichi Seika) Symulex Rhodamine Y. Toner F (Dainippon Ink) Rhodamine Y Toner (Dainippon Ink) Rose Toner (Tokyo color) Ultra Rose R (Toyo Ink) Sanyo Fanal Rose (Sanyo Dye) Fast Rose Lake FG (Tokyo Ink) Fanal Pink B (BASF) Halopont Pink 2BM (Dup) Fastel Pink B Supra (manufactured by ICI) Examples of CISolvent Red 49 include Rhodamine B Base (manufactured by Sumitomo Chemical) and Solvent Rhodamine B Cone (manufactured by Ikeda Chemical).

(3) Resin containing amino group(Where R⁶, R⁷, And R⁹Is hydrogen or alkyl having 1 to 5 carbon atoms
Groups, these may be the same or different. D
Is an alkylene group having 1 to 5 carbon atoms or hydrogen. ) Or a copolymer with styrene [dimethylaminoethyl
Tacrylate-styrene copolymer (polymerization molar ratio: 10/90
(4) Quaternary ammonium salt(Where R⁹, R^Ten, R¹¹And R¹²Is an aromatic carbon with 3 to 17 carbon atoms
A hydrocarbon or an aliphatic hydrocarbon, X Represents an anion
I forgot. Anions include halides, phosphates,
Particularly preferred are halides such as fonates and nitrates.
No. Examples of this include tetramethylphenylammonium chloride, tetrabutylammonium chloride, and tetrabutylammonium bromide.

(5) Metal complex dye represented by the following general formula (However, X, Y, and Z represent hydrogen, a halogen, a carboxyl group, a hydroxyl group, a nitrile group, a sulfone group, and a sulfamide group, and A ⁺ represents H, K, Na, or an aliphatic ammonium cation.) As an example, the following structural formulas (5-1) to (5-
6).

(6) Salicylic acid metal salt or metal salt of salicylic acid derivative (Wherein R ¹³ , R ¹⁴ and ¹⁵ are preferably hydrogen or an alkyl group having 1 to 10 carbon atoms is an allyl group. R ¹³ , R ¹⁴ and ¹⁵ may be the same or different at the same time. It is any metal selected from Zn, Ni, Co, Pb and Cr.) The metal salt represented by such a general formula is CLARK, JLKaO, H (1
948) It can be easily synthesized by the method described in J. Amer. Chem, Soc 70, 2151. For example, zinc is obtained by adding 2 mol of salicylic acid sodium salt (including the sodium salt of salicylic acid derivative) and 1 mol of zinc chloride in a solvent, mixing, heating and stirring. If the metal salt is other than a zinc salt, it can be produced according to the above method.

The amount of the triboelectric charge imparting substance to be added is 0.1 to 60 parts by weight, preferably 0.5 to 40 parts by weight, based on 100 parts by weight of the coating resin (low surface energy substance). In addition, these triboelectric charge imparting substances may be used alone or in combination of two or more.

When the conductive material and the triboelectric substance are used in combination,
The cleaning agent (cleaning carrier) increases the cleaning electric field and immediately raises the Q / M so that cleaning can be performed well. Total amount of conductive material and triboelectric substance is coating resin (low surface energy substance)
0.1 to 100 parts by weight, preferably 0.5 to 80 parts by weight, per 100 parts by weight is suitable.

Although the description so far has been directed to an apparatus using an electrophotographic photosensitive member, it is a matter of course that an electrostatic recording member may be used instead of the photosensitive member.

Next, examples and comparative examples will be described. Parts here are by weight.

Example 1 An average particle diameter of about 100 μm as a carrier for a two-component developer
m steel beads (Micro Shot SF manufactured by SHINTO BRATOR)
-100) was prepared.

Further, a mixture having the following formulation was kneaded on a two-roll mill under heating, cooled, and pulverized and classified to prepare a toner for a two-component developer having a particle size of 5 to 20 μm.

100 parts of polystyrene (D-125, manufactured by Esso) 100 parts of metal-containing dye (Spilon Black BH, manufactured by Hodogaya Chemical) 5 parts 10 parts of carbon black (# 44 manufactured by Mitsubishi Kasei) 100 parts of these carriers and 3.0 parts of toner are mixed. Thus, a two-component developer was prepared. The charge amount (Q / M) of the toner in this developer by a blow-off method was −24 μc / g.

Meanwhile, a cleaning carrier (cleaning agent)
First, a coating solution consisting of 100 parts of silicone resin (Toray Silicone SR206), 5 parts of Ketjen Black EC / DJ500 (manufactured by Lion Akzo), and 1500 parts of toluene was prepared. 5 kg of oxidized iron powder with a diameter of 100 μm is put in a flowing medium and the above coating liquid is
The dispersion was sprayed under heating at 0 ° C., and the coated product was taken out of the coating apparatus, placed in a thermostat, and heated at 200 ° C. for 2 hours to cure the silicone film.

The copying machine shown in FIG. 1 (using a selenium-based photoreceptor,
Uniformly charged so that the surface potential of the photoconductor 1 becomes +800 V;
A bias of +250 V is applied to the cleaning roller 71 and a bias of +300 V is applied to the collection roller 74).
Copies were obtained at a rate of 30 sheets per minute, and the toner consumed in the developing unit 4 was supplied. Table 1 summarizes the results of this running test.

Examples 2 to 6 The silicone resin of Example 1 (Tore Silicone SR24
06) with another silicone resin [(Example 2: KR271, Example
3: KR251 (all manufactured by Shin-Etsu Chemical Co., Ltd.), Example 4: SR2115,
Example 5: A cleaning agent was prepared in exactly the same manner as in Example 1 except that SR2400 (both made by Toray Silicone Co., Ltd.) and Example 6: KR3093 (made by Shin-Etsu Chemical Co., Ltd.) were used. I made a developer. The results of running the same running test as in Example 1 using these were summarized in Table 1.

Example 7 The carrier of Example 1 (steel beads having an average particle diameter of about 100 μm) was prepared as a carrier for a two-component developer.

On the other hand, a mixture having the following formulation was kneaded under heating on two roll mills, cooled and then pulverized and classified to prepare a two-component developer toner having a particle size of 5 to 20 μm.

Polystyrene (D-125 manufactured by Esso) 100 parts Dye (Special Black SB manufactured by Orient Chemical) 5 parts Carbon black (# 44 manufactured by Mitsubishi Kasei) 100 parts 100 parts of these carriers and 3.0 parts of toner are mixed to form two components. A system developer was prepared. Q / M in this developer is 20
It was measured as μc / g.

Meanwhile, a cleaning carrier (cleaning agent)
First, polytetrafluoroethylene (solid content: 60%: D-1, manufactured by Daikin Industries, Ltd.) 250 parts Ketjen Black EC / DJ500 (manufactured by Lion Akzo) 5 parts Fluorine surfactant (FC-134, Sumitomo 3M) A coating solution consisting of 1500 parts of a 1% aqueous solution of the above was prepared, and 5 kg of oxidized iron powder having an average particle size of 100 μm was put into a rotating disk type fluidized bed particle coating apparatus and the coating liquid was added to 8 parts of the coating fluid.
It was sprayed under heating at 0 ° C., and the coated material was taken out of the coating apparatus, placed in a thermostat, and heated at 350 ° C. for 2 hours to cure the fluorine film.

The two-component developer and the cleaning carrier (cleaning agent) are uniformly charged so that the surface potential of the photoreceptor 1 becomes -600 V using an organic photoreceptor as shown in FIG. -250V for the cleaning roller 71
, And a bias of -300 V was applied to the collecting roller 74) to obtain 30 copies per minute, and to replenish the toner consumed in the developing unit 4. Table 2 summarizes the results of this running test.

Examples 8 to 13 The fluororesin of Example 7 (D-1, manufactured by Daikin Industries, Ltd.) was replaced with another fluororesin [Example 8: TEF (851-214, manufactured by DuPont),
Example 9: Mixture of TEF and bronze (MG-3060, manufactured by Daikin Industries, Ltd.), Example 10: TEF (856-204, manufactured by DuPont), Example 11: Epoxy-modified Teflon enamel (S954)
-101, manufactured by DuPont), Example 12: Teflon S (manufactured by DuPont), Example 13: ethylene tetrafluoride-hexafluoropropylene copolymer (ND-1, manufactured by Daikin)] Prepared a cleaning agent in exactly the same manner as in Example 7, and produced a two-component developer. The results of running the same running test as in Example 7 using these were summarized in Table-2.

Examples 14 to 19 Each of the conductive substances in the composition of the cleaning carrier liquid used in Example 1 was [Example 14: 30 parts of ECT52 (manufactured by Titanium Industry Co., Ltd.), Example 15: Ketjen Black EC / DJ600 (Lion Akzo) 5 parts, Example 16: W-1 (Mitsubishi Metals) 30 parts, Example 17: 23K (Hakusui Chemical) 30 parts, Examples
18: 30 parts of conductive zinc oxide No. 1 (manufactured by Honjo Chemical Co., Ltd.), Example 19: 5 parts of VULCAN XC-72 (manufactured by Cabot) 5 parts] The same two-component developer as in Example 7 was prepared. Table 3 summarizes the results of running the same running test as in Example 1 using this.

In the above Examples 14 to 19, 250 parts of polytetrafluoroethylene (D-1) were used instead of 100 parts of the silicone resin (Toray Silicone SR2405) to prepare a cleaning carrier liquid, and the toner was used in Example 7. When a running test similar to that of Example 7 was performed using the same, results similar to the results of Examples 14 to 19 were found.

Examples 20 to 23 In addition to the composition of the cleaning carrier liquid used in Example 1, a triboelectric (positive) substance [Example 20: Polyamide S-40HA (resin containing an amino group, manufactured by Sanyo Chemical Co., Ltd.), 21: Rhodamine yellow toner (xanthene dye, manufactured by Dainippon Ink and Chemicals, Inc.), Example 22: styrene-dimethylaminoethyl methacrylate copolymer (polymerization molar ratio 90/10), Example 23: Halopont Pink 2BM
(Xanthene dye, manufactured by DuPont), Example 24: Special Black SB (Nigrosine-based dye, manufactured by Orient Chemical Co., Ltd.), Example 25: Nigrosine-based LK (Nigrosine-based dye, manufactured by BASF)] A cleaning carrier liquid was prepared in exactly the same manner as in Example 1 except for the above, and a two-component developer was prepared. Example 1 using this
A summary of the results of the same running test as
It is shown in FIG.

Examples 26 to 31 In addition to the composition of the cleaning carrier liquid used in Example 7, a triboelectric charging (minus) substance [Example 26: Empara 7
0 (chlorinated paraffin, manufactured by Ajinomoto Co.), Example 27: polyester resin (382A, manufactured by Kao Soap Co.), Example 28: BONTRON
-E82 (3,5-di-tert-butyl Cr complex, manufactured by Orient Chemical Co., Ltd.), Example 29: Nihonthrene Red Violet RH D / P
(Thioindigo dye, manufactured by Sumitomo Chemical Co., Ltd.), Example 30: Dee
p Red Violet (thioindigo pigment, manufactured by Toyo Ink Co., Ltd.), Example 31: Sumitone Fest Red Violet RH (thioindigo pigment, manufactured by Sumitomo Chemical Co., Ltd.)], and cleaning was performed in exactly the same manner as in Example 7 except that 10 parts were added. A carrier liquid was prepared, a cleaning agent was prepared, and a two-component developer was prepared. Table 4 summarizes the results of the same running test of Example 7 using this.

Examples 32-44 The conductive substances in the composition of the cleaning carrier liquid used in Example 7 were each changed to [Example 32: 30 parts of ECT52 (manufactured by Titanium Industry Co., Ltd.), Example 33: Ketjen Black EC / DJ600 (Lion) Akzo) 5 parts, Example 34: W-1 (Mitsubishi Metals) 30 parts, Example 35: 23K (Hakusui Chemical) 30 parts, Examples
36: 30 parts of conductive zinc oxide No. 1 (manufactured by Honjo Chemical Co., Ltd.), Example 37: 5 parts of VULCAN XC-72 (manufactured by Cabot Corporation), and a triboelectric charge imparting substance [Example 38] : Nigrosine dye (Spirit Black SB, manufactured by Orient Chemical Co.) 5 parts, Example 39: Nigrosine dye (spirit black No. 850, manufactured by Sumitomo Chemical Co., Ltd.) 5 parts, Example 40: Basic dye (Simrex Rhodamine Y Toner) F, 5 parts by Dainippon Ink and Chemicals, Example 41: 5 parts of a basic dye (rose toner, manufactured by Tokyo Color Materials Co., Ltd.), Example 42: 5 parts of tetrabutylammonium chloride, Example 43: tetramethyl phthalate 5 parts of enyl ammonium chloride, Example 44: 5 parts of styrene-dimethylaminoethyl methacrylate copolymer]
A cleaning carrier was prepared in exactly the same manner as in Example 7 except that the addition was carried out as described above, and a two-component developer was prepared. The results of running the same running test as in Example 7 using these are summarized in Table-5.

Examples 45 to 50 Cleaning was carried out in exactly the same manner as in Example 1 except that the conductive substance having the composition of the cleaning carrier liquid used in Example 1 was changed and a triboelectric (positive) substance was added as described below. Prepare carrier liquid and make cleaning agent, A two-component developer was made. Table 6 summarizes the results of the same running test as in Example 1 using this.

Examples 51 to 68 A cleaning carrier liquid was prepared in exactly the same manner as in Example 7 except that a conductive substance and a triboelectric (minus) substance were added to the composition of the cleaning carrier liquid used in Example 7 as described below. A cleaning agent was prepared, and a two-component developer was prepared.

Table 6 summarizes the results of running tests exactly the same as in Example 7 using these.

Comparative Example 1 except that the cleaning carrier was not coated with a low surface energy material in which a conductive material was dispersed.
Or, when the running test was performed in the same manner as in 7, the density of the copy image was reduced to 1.28 at the start, 0.7 to the 500th sheet, no image was obtained at the 100,000th sheet, and the density of the cleaning image on the photoreceptor. Was 0.07 at the start, and 1.20 on the 500th sheet. At the 100,000th sheet, the surface of the photoreceptor was significantly stained.

〔effect〕

As is clear from the description of the embodiment, according to the image receiving apparatus of the present invention, a high-quality copy can be obtained without image contamination even when copying 100,000 sheets. Further, it was found that the surface of the photoreceptor after cleaning was very clean visually.

On the other hand, in the case of using a copying machine (comparative example) in which the electric resistance of the cleaning carrier is larger than the electric resistance of the two-component developer carrier, dirt is seen on the surface of the photoreceptor after copying about 1,000 sheets. Occurrence of poor cleaning was observed.

[Brief description of the drawings]

FIG. 1 is a schematic view of an electrophotographic copying apparatus according to the present invention. DESCRIPTION OF SYMBOLS 1 ... Photoconductor, 2 ... Charger 3 ... Optical system 4, Developing part 5 ... Transfer charger, 6 ... Separation charger 7 ... Cleaning part, 8 ... Transfer paper 9 ... Separation nail, 41 Developing sleeve 41 Magnet 42 Sensor 43 Paddle wheel 71 Cleaning roller 72, 73 Pumping roller 74 Collection roller 75 Cleaning scrubber 76 Collection blade 77 …… Discharge screw

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Hiroyuki Fushimi 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (72) Kayo Makita 1-3-6 Nakamagome, Ota-ku, Tokyo Ricoh Co., Ltd. (56) References JP-A-59-182485 (JP, A) JP-A-58-102273 (JP, A) JP-A-58-55960 (JP, A) JP-A-59-166968 (JP, A) JP, A) JP-A-55-155363 (JP, A) JP-A-61-206443 (JP, A)

Claims (8)

(57) [Claims] 1. An electrostatic charge image is formed on a photoreceptor, visualized with a two-component developer, and the toner image is transferred to transfer paper. In the electrophotographic copying apparatus to be removed by the cleaning unit, the carrier contained in the magnetic brush cleaning unit is an oxidized iron powder whose surface is coated with a low surface energy material in which a conductive material is dispersed. Characteristic electrophotographic copying machine. 2. A copying apparatus according to claim 1, wherein said low surface energy substance is a silicone resin. 3. A copying apparatus according to claim 1, wherein said low surface energy substance is a fluorine resin. 4. A copying apparatus according to claim 1, wherein said coating layer contains a triboelectric charge imparting substance dispersed therein. 5. The copying apparatus according to claim 1, wherein said conductive substance is at least one selected from TiO ₂ , SnO ₂ , ZnO, conductive fiber and carbon black. 6. The conductive material is a low surface energy material.
2. The copying apparatus according to claim 1, wherein the content of the copier is 0.1 to 100 parts by weight relative to 0 parts by weight. 7. The triboelectric charge-imparting substance is a nigrosine dye,
The copying apparatus according to claim 4, wherein the copying apparatus is at least one selected from a xanthene dye, a compound having an amino group, a metal complex salt dye, a metal salt of salicylic acid, and a metal salt of a salicylic acid derivative. 8. A copying apparatus according to claim 4, wherein said triboelectric charge-imparting substance is added at a ratio of 0.05 to 80 parts by weight based on 100 parts by weight of the low surface energy substance.