JPH086435A - Electrophotographic equipment - Google Patents

Abstract

(57) [Summary] [Object] It is an object of the present invention to provide an electrophotographic apparatus having excellent cleaning properties from the initial use to the repeated use and capable of obtaining a high-quality image. According to the present invention, in an electrophotographic apparatus having an image carrier and a developing unit and a blade cleaning unit from the upstream side, a polishing unit using a brush for polishing the surface of the image carrier is provided downstream of the cleaning unit. Is an electrophotographic apparatus.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic apparatus,
Specifically, it relates to an electrophotographic apparatus having a blade cleaning means and a polishing means.

[0002]

2. Description of the Related Art Conventionally, various cleaning means for removing residual toner on an image bearing member have been used. However, in view of downsizing of the apparatus, simplification and size of cleaning effect, urethane rubber is used. The so-called blade cleaning means for scraping off the residual toner by bringing a rubber blade such as the above into contact with the surface of the image carrier is most preferably used.

However, also in this case, foreign matter such as paper fibers may be deposited on the contact portion between the image bearing member and the blade to damage the surface of the image bearing member or cause a partial cleaning failure. Further, corona products generated at the time of charging adhere to the surface of the image bearing member, but if the contact pressure of the blade with respect to the image bearing member is increased to remove the deposits, the blade may be reversed due to friction. There was also. These problems were particularly remarkable in the image bearing member in which the surface layer having a relatively low surface hardness and a large surface friction resistance is the resin layer.

Japanese Patent Laid-Open No. 59-226370 discloses a cleaning device for polishing the surface of an image bearing member with a web provided downstream of a blade cleaning means in order to prevent black streaks caused by residual toner. There is.

However, with this method, it is difficult to reduce the size of the apparatus and to evenly bring the web into contact with the surface of the image carrier.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems and to provide an electrophotographic apparatus which has excellent cleaning properties from the initial use to the repeated use and is capable of obtaining a high quality image. To provide.

[0007]

That is, according to the present invention, in an electrophotographic apparatus having an image carrier and a developing unit and a blade cleaning unit from the upstream side, the surface of the image carrier is polished downstream of the cleaning unit. The electrophotographic apparatus is characterized by having a polishing means with a brush.

The image bearing member used in the present invention is roughly classified into an electrostatic recording member having a resin layer called a dielectric layer and an electrophotographic photosensitive member having a photosensitive layer. When the image carrier is an electrophotographic photosensitive member, the structure has a photosensitive layer on a conductive support,
The photosensitive layer is roughly classified into a surface layer and a photosensitive layer further having a protective layer. The photosensitive layer is a single layer type containing both the charge generating substance and the charge transporting substance in the same layer, or a laminated layer in which a charge generating layer containing the charge generating substance and a charge transporting layer containing the charge transporting substance are laminated. There are types. When the protective layer is provided, the laminated type photosensitive layer is more preferable than the problem of deterioration of the characteristics of the photoconductor due to migration of the protective layer components into the photosensitive layer. As the constitution of the laminated type photosensitive layer, there are one in which a charge generation layer and a charge transport layer are laminated in this order on a conductive support, and conversely, one in which a charge transport layer and a charge generation layer are laminated in this order. In the invention, it is more preferable that the charge generation layer and the charge transport layer are laminated in this order.

The conductive support used in the present invention may be any one as long as it has conductivity. For example, a metal such as aluminum, copper, chromium, nickel, zinc or stainless is molded into a drum or sheet. A metal foil such as aluminum or copper laminated on a plastic film, aluminum, indium oxide, tin oxide or the like deposited on a plastic film, or a conductive substance applied alone or with a binder resin to form a conductive layer. Examples include metal, plastic film, and paper.

The charge generation layer of the laminated type photoreceptor includes azo pigments such as Sudan Red and Diane Blue; quinone pigments such as pyrene quinone and anthanthrone; quinocyanine pigments; perylene pigments; indigo pigments such as indigo and thioindigo; and phthalocyanine pigments. Dispersing the charge generating substance in a binder resin such as polyvinyl butyral, polystyrene, polyvinyl acetate and acrylic resin,
It is formed by coating this dispersion or vacuum-depositing the pigment. The thickness of such a charge generation layer is 5
It is not more than μm, preferably 0.05 to 3 μm.

The charge transport layer of the multi-layer type photoreceptor is formed by using a coating solution prepared by dissolving a charge transport substance such as a pyrazoline compound, a hydrazone compound, a styryl compound and a triarylamine compound in a resin having a film-forming property. Examples of the resin having such a film forming property include polyester, polycarbonate, polystyrene and polymethacrylic acid ester. The thickness of the charge transport layer is 5 to 40 μm, preferably 10 to 30 μm.

In the present invention, as the material of the photosensitive layer,
In addition to the above, Se, Se-Te alloy, Se-As
Alloys, vapor-deposited films of Se-Sb alloys and Se-Bi alloys, organic photoconductor layers such as PVK / TNF, amorphous Si photoconductor layers, inorganic photoconductors such as ZnO or CdS were dispersed in a binder resin. The thing etc. can be used.

The binder resin which can be used in the protective layer of the present invention includes polycarbonate resin, polyester resin, polyarylate resin, polystyrene resin, polyethylene resin, polypropylene resin, polyurethane resin, acrylic resin, epoxy resin, silicone resin, Examples thereof include cellulose resins, polyvinyl chloride resins, phosphazene resins, melamine resins, and vinyl chloride-vinyl acetate copolymers. These resins can be used alone or in combination of two or more kinds.

Among the above resins, the surface hardness of the protective layer,
A curable resin is preferably used from the viewpoints of abrasion resistance, dispersibility of fine particles, and stability after dispersion. That is, the above-mentioned conductive particles and fluorine atom-containing resin particles are dispersed in a solution containing a monomer or an oligomer that is cured by heat or light to prepare a coating solution for a protective layer, and this solution is applied onto a photosensitive layer. The protective layer formed by curing is more preferable in terms of dispersibility hardness and abrasion resistance.

The monomer or oligomer which is cured by heat or light has, for example, a functional group which causes a polymerization reaction at the end of the molecule by the energy of heat or light, of which the number of repeating structural units of the molecule is about 2 to 20. A relatively large molecule is an oligomer, and a smaller molecule is a monomer. Examples of the functional group that causes the polymerization reaction include acryloyl group, methacryloyl group, a group having a carbon-carbon double bond such as a vinyl group, a dianol group, a group that causes ring-opening polymerization such as a cyclic ether group, or a group of phenol and formaldehyde. As such, there may be mentioned those in which two or more kinds of molecules react to cause polymerization.

The thickness of the protective layer of the present invention is 0.2 to 10 μm.
Is preferable, and more preferably 0.5 to 6 μm.

In the present invention, it is particularly preferable that the surface layer of the image holding member contains lubricating particles in order to further improve the cleaning property and the transfer property. As lubricating particles,
Fluorine atom-containing resin particles are preferable, and as the fluorine atom-containing resin particles used in the present invention, tetrafluoroethylene resin, trifluoroethylene chloride resin, hexafluoroethylenepropylene resin, vinyl fluoride resin, vinylidene fluoride resin, It is preferable to appropriately select one kind or two or more kinds from the difluorodichloroethylene resin and the copolymers thereof, and the tetrafluoroethylene resin and the vinylidene fluoride resin are particularly preferable. The molecular weight of the resin particles and the particle size of the particles can be appropriately selected and are not particularly limited.

The proportion of fluorine atom-containing resin particles in the protective layer is preferably 5 to 70% by weight, more preferably 10 to 60% by weight, based on the total weight of the surface layer. If the proportion of the fluorine atom-containing resin particles is more than 70% by weight, the mechanical strength of the surface layer tends to decrease, and if the proportion of the fluorine atom-containing resin particles is less than 5% by weight, the releasability of the surface layer and the surface layer The abrasion resistance and scratch resistance may become insufficient.

In the present invention, the fluorine atom-containing resin particles are prevented from aggregating with each other in the resin solution.
The protective layer may contain a fluorinated surfactant, a fluorinated silane coupling agent, a fluorinated silicone oil or a fluorinated graft polymer. By containing the above-mentioned fluorine atom-containing compound, the dispersibility and dispersion stability of the fluorine atom-containing resin particles in the resin solution are markedly improved, and a coating liquid having very good dispersibility can be obtained.

The addition amount of these fluorine atom-containing compounds is
It is preferably 0.1 to 50% by weight, and particularly preferably 1 to 30% by weight, based on the weight of the fluorine atom-containing resin particles.

Preferred examples of the fluorinated silane coupling agent, fluorinated silicone oil, fluorinated surfactant and fluorinated graft polymer which can be used in the present invention are shown below, but the compounds are not limited to these compounds. is not.

Preferred fluorine-containing silane coupling agents are CF ₃ CH ₂ CH ₂ Si (OCH ₃ ).
₃ , C ₄ F ₉ CH ₂ CH ₂ Si (OCH ₃ ) ₃ , C ₆ F
₁₃ CH ₂ CH ₂ Si (OCH ₃ ) ₃ , C ₈ F ₁₇ CH ₂ C
H ₂ Si (OCH ₃ ) ₃ , C ₈ F ₁₇ CH ₂ CH ₂ Si
(OCH ₂ CH ₂ OCH ₃ ) ₃ , C ₁₀ F ₂₁ Si (OCH
₃ ) ₃ , C ₆ F ₁₃ CONHSi (OCH ₃ ) ₃ , C ₈ F
₁₇ CONHSi (OCH ₃ ) ₃ , C ₇ F ₁₅ CONHCH
_{2 CH 2 CH 2 Si (OCH} 3) 3, C 7 F 15 CONH
CH ₂ CH ₂ CH ₂ Si (OC ₂ H ₅ ) ₃ , C ₇ F ₁₅ C
OOCH ₂ CH ₂ CH ₂ Si (OCH ₃ ) ₃ , C ₇ F ₁₅
COSCH ₂ CH ₂ CH ₂ Si (OCH ₃ ) ₃ , C ₈ F
₁₇ SO ₂ NHCH ₂ CH ₂ CH ₂ Si (OC ₂ H ₅ )
₃ ,

[0023]

[Outer 1] C ₈ F ₁₇ CH ₂ CH ₂ SCH ₂ CH ₂ Si (OCH ₃ )
₃ , C ₁₀ F ₂₁ CH ₂ CH ₂ SCH ₂ CH ₂ Si (OCH
₃ ) ₃ ,

[0024]

[Outside 2] And the like.

The preferred fluorinated silicone oil is

[0026]

[Outside 3] Is mentioned. Here, R in the formula is -CH ₂ CH ₂ CF ₃
And m and n are positive integers.

Preferred fluorine-containing surfactants are X-SO ₂ NRCH ₂ COOH and X-SO ₂ NRC.
H ₂ CH ₂ O (CH ₂ CH ₂ O) nH (n = 5, 10,
_{15), X-SO 2 N} (CH 2 CH 2 CH 2 OH) 2,
X-RO (CH ₂ CH ₂ O) n (n = 5, 10, 1
5), X- (RO) n (n = 5 to 20), X- (RO)
nR (n = 5 to 20),

[0028]

[Outside 4] _{X-COOH, X-CH 2} CH 2 COOH, X-ORC
_{OOH, X-ORCH 2 COOH,} X-SO 3 H, X-
ORSO ₃ H, X-CH ₂ CH ₂ OH,

[0029]

[Outside 5] And the like. Here, R is an alkyl group in the formula, an allyl group, an aralkyl group, X is _{-CF 3, -C 4 F 9,} -
A fluorocarbon group such as C ₈ F ₁₇ is shown.

The preferred fluorine-based graft polymer is

[0031]

[Outside 6]

Examples of the material of the blade used for the blade cleaning means in the present invention include rubber, plastic, metal and ceramics. Among them, the elastic rubber blade is superior in cleaning property to other materials. Examples of the elastic rubber material include urethane rubber, neoprene rubber, silicone rubber, and the like, and urethane rubber is particularly preferable in that elasticity can be maintained for a long period of time.

The blade cleaning means in the present invention need only have the function of cleaning the developer, and it is preferable that the contact pressure of the cleaning blade on the image carrier is set to the necessary minimum. In order to minimize the damage given to the surface of the image carrier and effectively remove the residual developer, it is sufficient to adjust the contact angle and the contact pressure of the blade edge to the image carrier. Is preferably 15 degrees or more, particularly 45 degrees or less, in the counter direction with respect to the moving direction of the image carrier, and the contact pressure is preferably 1 gr / cm or more and 20 gr / cm or less, particularly 3
It is preferably not less than gr / cm and not more than 10 gr / cm.

The polishing means for the surface of the image bearing member in the present invention is installed downstream of the blade cleaning means and upstream of the developing means. The polishing means brings the polishing member into contact with the surface of the image bearing member and polishes it. The polishing member does not always have to be in contact with the image carrier, and may be in contact, for example, only when the image carrier is moved or only for a part of the entire electrophotographic process. Particularly, it is necessary to polish the surface of the image bearing member after the electrophotographic apparatus has been stopped for a long time. Therefore, contacting the switch for a certain time only when the switch is on is very effective in reducing the amount of abrasion.

In the polishing means of the present invention, a brush-shaped member is brought into contact with the image carrier. Examples of the material of such a brush-like member include metal, resin, fibers such as glass and carbon, magnetic powder such as ferrite, magnetite and iron powder, or oxide powder such as alumina and silica.

When a magnetic powder brush is used as the polishing means, the magnetic powder on the magnetic roller polishes the surface, and the surface layer comes into contact with the surface of the image carrier containing the fluorine atom-containing resin particles to clean the surface. Along with polishing, when the surface layer contains fluorine atom-containing resin particles, the surface of the carrier is refreshed by breaking such fluorine atom-containing resin particles, but the effect is that of the particles of magnetic powder. Depending on the diameter, if the particle diameter is too small, no sufficient effect can be obtained, and if it is too large, the carrier surface becomes uneven, resulting in unevenness on the image. Therefore, the average particle size of the magnetic powder is preferably 5 μm or more and 50 μm or less. Further, in order to achieve both the effect of flattening the surface and the sufficient crushing effect, it is effective to have two or more peaks in the particle size distribution, and in particular, peaks of 10 μm or less and 10 to 50 μm, respectively. It is preferable to use a magnetic powder having a certain particle size distribution.

FIG. 1 is a side view of the cleaning means and polishing means of the present invention.

In the figure, 1 is an image carrier, 2 is a cleaning blade, and a blade member such as rubber is provided at the tip of a flexible supporting member such as metal. Then, the blade members are arranged in a so-called counter direction in which the blade members face each other in the rotation direction of the image carrier (the direction of the arrow), and the developer remaining on the surface of the image carrier is removed by cleaning.

Reference numeral 3 denotes a polishing means, which is a magnetic roller arranged on the downstream side of the cleaning blade 2 and in the vicinity of the image carrier, having a plurality of magnetic poles along the circumference of the roller and rotating in the direction of the arrow. Around the magnetic roller, magnetic powder 4 made of ferrite is arranged in a brush shape, and this magnetic powder brush comes into contact with the surface of the image carrier, and the surface of the image carrier moves as the image carrier moves. Perform polishing.

Reference numeral 5 is a member for accommodating the developer removed by the cleaning blade 2.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples.

[0042]

【Example】

(Example 1) Alcohol-soluble polyamide resin (Amilan CM-8000, manufactured by Toray Industries, Inc.) 10 parts (parts by weight, hereinafter the same) and methoxymethylated 6 nylon resin (Toresin EF-30T, Teikoku) were placed on an aluminum cylinder. A solution obtained by dissolving 30 parts of Kagaku Co., Ltd. in a mixed solvent of 150 parts of methanol and 150 parts of butanol is applied by dip coating and dried at 90 ° C. for 10 minutes to give a film thickness of 1
An undercoat layer of μm was formed.

Next, the following equation

[0044]

[Outside 7] Into a solution in which 4 parts of the disazo pigment represented by 4 parts, 2 parts of butyral resin (S-REC BL-S, manufactured by Sekisui Chemical Co., Ltd.) and 100 parts of cyclohexanone are dispersed in a sand mill for 48 hours are added 100 parts of tetrahydrofuran (THF). As a result, a dispersion liquid for the charge generation layer was obtained. This dispersion was dip-coated on the undercoat layer and dried at 80 ° C. for 15 minutes to form a charge generation layer having a thickness of 0.15 μm.

Next, the following formula

[0046]

[Outside 8] A solution prepared by dissolving 10 parts of a triarylamine compound represented by and 10 parts of a polycarbonate resin (Iupilon Z-200, manufactured by Mitsubishi Gas Chemical Co., Inc.) in a mixed solvent of 20 parts of dichloromethane and 50 parts of monochlorobenzene is charged as described above. A charge generation layer having a film thickness of 20 μm was formed by dip coating on the generation layer and drying at 120 ° C. for 60 minutes.

Next, a dispersion liquid for the protective layer was prepared by the following procedure.

As a binder resin, the following formula

[0049]

[Outside 9] 25 parts of an acrylic curable monomer represented by 1., 2.0 parts of 2-methylthioxanthone as a photopolymerization initiator and 300 parts of toluene are mixed in a tetrafluoroethylene resin particle (Lubron L-2, manufactured by Daikin Industries, Ltd.) 25 Parts and fluorine-based silane coupling agents (C ₄ F ₉ CH ₂ CH ₂ Si
20 parts of (OCH ₃ ) ₃ ) are mixed and mixed with a sand mill to make 4
By performing time dispersion, a dispersion liquid for the protective layer was obtained. This dispersion is spray-coated on the charge transport layer, dried and then exposed to a high pressure mercury lamp at a light intensity of 800 mW / cm ² for 20 minutes.
By irradiating ultraviolet rays for 2 seconds, a protective layer having a film thickness of 1 μm was formed.

Using the photoconductor manufactured by the above procedure as an image carrier, the cleaning unit of a digital copying machine (GP-55, made by Canon) was remodeled as shown in FIG. An image output durability test was performed.

The material of the cleaning blade at this time was urethane rubber, the contact angle between the image carrier and the blade was 30 degrees, and the contact pressure was 5 gr / cm. A magnetite rod was used as the magnetic roller, and this was rotated in the opposite direction of the rotation of the image bearing member at a peripheral speed of 0.5 times. The magnetic powder used was magnetite powder with an average particle size of 30 μm.

As a result of durability evaluation, in the electrophotographic apparatus of this embodiment, there was no scratch on the surface of the image bearing member or cleaning failure even after the durability of 100,000 sheets.
The above-mentioned developer transfer efficiency was maintained and a good image was obtained. The transfer efficiency is [(1-amount of developer collected by cleaner / amount of developer consumed from developing device) × 100.
%].

Comparative Example 1 The same evaluation was performed using the same electrophotographic apparatus as in Example 1 except that the magnetic roller was not used.

As a result, the urethane rubber blade was turned up in the rotational direction of the image bearing member at the time of image output durability of 25,000 sheets, resulting in poor cleaning and scratches on the surface of the image bearing member.

(Example 2) Similar to Example 1, a charge generating layer of a photoconductor was formed.

Next, the following formula

[0057]

[Outside 10] In a mixed solution of 10 parts of a triarylamine compound represented by the following, 10 parts of a polycarbonate resin (Upilon Z-200, manufactured by Mitsubishi Gas Chemical Co., Inc.), 20 parts of dichromesin, and 50 parts of monochlorobenzene, tetrafluoroethylene resin particles (rubron) L-2, manufactured by Daikin Industries, Ltd.) and 5 parts of fluorine graft polymer (GF-300, manufactured by Daikin Industries, Ltd.)
Part and 20 parts of monoclebenzene were dispersed in a sand mill for 2 hours, and then a mixed solution was applied onto the charge generation layer by dip coating and dried at 120 ° C. for 60 minutes to obtain a film thickness of 20 μm.
The charge transport layer of was formed to obtain a photoreceptor. Using this as an image bearing member, image forming durability was performed in the same manner as in Example 1. As a result, fogging occurred due to abrasion of the surface layer of the photoconductor on 100,000 sheets, but up to 100,000 sheets, scratches and cleaning defects did not occur, and a transfer efficiency of 90% or more was maintained during the entire durability, and a good image was obtained. Was obtained.

(Example 3) The binder resin for the protective layer of Example 1 was prepared by the following formula.

[0059]

[Outside 11] A photoconductor was prepared in the same manner as above, except that the acrylic curable monomer represented by (4) was used and the fluorine atom-containing resin particles were changed to trifluorochloroethylene resin particles (Daiflon, Daikin Industries, Ltd.).

Next, a cleaning device of a color copying machine (CLC-500, manufactured by Canon) using a reversal development system equipped with a semiconductor laser and a non-magnetic developer using this as an image carrier was modified for the present embodiment. A machine was used to evaluate the output of 30,000 images.

The contents of the modification were that the contact angle between the cleaning blade (made of urethane rubber) and the image bearing member was 25 degrees and the contact pressure was 10 gr / cm. Further, a magnetite magnetic roller having a diameter of 15 mm was installed at the position indicated by 3 in FIG. As the magnetic powder, magnetic powder made of ferrite (average particle size 20 mμ, particle size distribution having peaks at 5 mμ and 25 mμ) was used. The magnetic powder is attached in advance around the magnetic roller with a thickness of 2d (d is a gap between the magnetic roller and the image carrier).

As a result of the image output durability, no image defects caused by scratches on the surface of the image bearing member or poor cleaning occurred until the end of the 30,000-sheet durability, and the transfer efficiency of the developer was always 92%.
I was able to maintain the above.

(Comparative Example 2) In Example 3, the image forming durability was carried out in the same manner except that the magnetic roller was not provided in the upstream portion of the cleaner. When the durability was 2000 sheets, the blade turned over in the rotating direction of the image bearing member. , Cleaning failure occurred. Further, the transfer efficiency of the developer during running was 80% or less.

(Example 4) In Example 2, at the position 3 in FIG. 1, the length of the nylon hair is 5 mm, and the diameter of the hair is 50 m.
mu, except for using those nylon fibers brush density 20000 / cm ² in contact with contact pressure 3GR / cm ² as a polishing apparatus was subjected to image reproduction durability examined in the same manner.

As a result, a fog image was generated due to the abrasion of the photoconductor on 80,000 sheets, but up to 80,000 sheets, there were no scratches and poor cleaning, and a transfer efficiency of 90% or more was maintained during the entire durability, and a good image was obtained. Was obtained.

[0066]

As described above, according to the present invention, it has an excellent cleaning property from the initial use to the repeated use.
It was possible to provide an electrophotographic apparatus capable of obtaining a high-quality image.

[Brief description of drawings]

FIG. 1 is a side view of cleaning means and polishing means of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Image carrier 2 Cleaning blade 3 Polishing means 4 Magnetic powder 5 Developer storage member

Claims (3)

[Claims] 1. An electrophotographic apparatus having an image carrier and a developing means and a blade cleaning means from the upstream side, further comprising a polishing means by a brush for polishing the surface of the image carrier downstream of the cleaning means. And an electrophotographic device. 2. The electrophotographic apparatus according to claim 1, wherein the polishing means is a magnetic roller having magnetic powder arranged in a brush shape. 3. The electrophotographic apparatus according to claim 1, wherein the surface layer of the image bearing member contains fluorine atom-containing resin particles.