JP2004038208A - Multifunctional type contact transfer device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a multifunctional type contact transfer device in which miniaturization can be attained and excellent durability can be obtained especially when combined with an organic electrophotographic photoreceptor and to provide an image forming apparatus using the same. <P>SOLUTION: The transfer device is used in an image forming process at least having processes of electrostatic charging, image exposing, developing, transferring, fixing and cleaning. It is the contact transfer device of a system of applying electric field by coming into contact with the electrophotographic photoreceptor, is used in the image forming apparatus and has a photoreceptor surface characteristic regulating function besides an original electric field applying function. <P>COPYRIGHT: (C)2004,JPO

Description

The present invention relates to an electrophotographic process using an electrophotographic photoreceptor, and more particularly, to a contact transfer device used for image formation using a contact transfer system and an electrophotographic device and process using the same, and relates to the device of the present invention. The process is applied to copying machines, facsimile machines, laser printers, direct digital plate making machines, and the like.

An electrophotographic method using an electrophotographic photoconductor applied to a copier, a facsimile, a laser printer, a direct digital plate making machine, etc., involves at least primary charging, electrophotographic exposure, and development of the electrophotographic photoconductor. Thereafter, the method comprises a process of transferring and fixing a toner image to an image carrier (transfer paper), and cleaning the surface of the electrophotographic photosensitive member.

Here, the charging and transferring methods in the electrophotographic method are roughly classified into two types: a non-contact method and a contact method.
In the non-contact method, a high voltage is applied to a conductive member (thin wire, plate, etc.) fixed parallel to the photoconductor at a position away from the photoconductor, such as a corona discharge device, to charge, This is a method for performing transfer. As a method for relatively uniformly applying a uniform discharge to the surface of a photoreceptor, conventionally, it has been most commonly used in electrophotography.

On the other hand, in the contact charging or transfer system, a voltage is applied to a member such as a brush, a roller-like brush, a roller, a blade, or a belt having appropriate conductivity and elasticity to contact the surface of the photoreceptor to perform charging and transfer. (JP-A-63-149668, JP-A-7-281503, etc.).

This contact charging or transfer method is considered to cause chemical damage to the photosensitive member and the human body, since a smaller voltage is required to apply to charge or transfer the photosensitive member than the non-contact method. This method is advantageous in that the generation of ozone and the like is small, and is a charging and transferring method that has been rapidly spread in recent years.

In recent years, as personalization of copiers, facsimile machines, laser printers, and the like has progressed, there has been a demand for a smaller and more durable (maintenance-free) electrophotographic process.
As described above, in the electrophotographic process, various devices surround the photoreceptor. If the photoreceptor is made smaller (small diameter or small outer circumference) in order to reduce the size of the electrophotographic process, the arrangement of peripheral devices is reduced. There is a problem that it becomes very difficult.

For example, JP-A-6-342236, JP-A-8-202226, and JP-A-9-81001 disclose techniques for disposing a means for supplying a lubricity imparting agent to the surface of a photoreceptor around the photoreceptor. However, it is clear that such an arrangement of peripheral devices is difficult for miniaturization of the electrophotographic process.

On the other hand, as a photoreceptor used in the electrophotographic method, an organic photoreceptor has been widely used because of its low cost, high degree of freedom in designing the photoreceptor, and no pollution.
Organic electrophotographic photoreceptors include a photoconductive resin represented by polyvinyl carbazole (PVK), a charge transfer complex type represented by PVK-TNF (2,4,7-trinitrofluorenone), and a phthalocyanine-binder. And a function-separated type photoreceptor using a combination of a charge generation material and a charge transport material, and a function-separated type photoreceptor has been particularly noted.

The mechanism of the formation of an electrostatic latent image in this function-separated type photoreceptor is as follows: when light is irradiated after charging the photoreceptor, light passes through a transparent charge transport layer and is absorbed by the charge generating substance in the charge generation layer, The light-absorbing charge-generating substance generates charge carriers, which are injected into the charge-transporting layer, move in the charge-transporting layer according to the electric field generated by the charge, and neutralize the charge on the photoreceptor surface. Thus, an electrostatic latent image is formed. In a function-separated type photoreceptor, it is known and useful to use a charge transport material having absorption mainly in the ultraviolet region and a charge generation material having absorption mainly in the visible region.

When using a photoconductor of an organic photoconductor including such a function-separated type, it is possible to perform contact charging with high charging efficiency and a small generation amount of corona products such as ozone and NOx. It is very effective from the viewpoint of suppressing the generation of defects and avoiding the deterioration caused by exposing the photoreceptor to the corona product, thereby extending the life, and as described above, JP-A-56-104351. Many proposals have been made as disclosed in JP-A-57-178267, JP-A-58-40566, JP-A-58-139156, JP-A-58-150975, and the like. However, on the other hand, there is another problem due to physical contact of the photoreceptor as described below, in addition to the uneven charging.

That is, most charge transport substances have been developed as low molecular weight compounds, but since low molecular weight compounds alone do not have a film-forming property, they are usually dispersed and mixed with an inert polymer. However, the charge transport layer composed of a low-molecular charge transport material and an inert polymer is generally soft and has a disadvantage that the film is liable to be scraped by repeated use in an electrophotographic process. This is a major issue in achieving durability, and improvement is strongly desired.

SUMMARY OF THE INVENTION An object of the present invention is to provide an image forming apparatus that meets these requirements. In particular, it is possible to reduce the size of the image forming apparatus. An object of the present invention is to provide a mold contact transfer device and an image forming apparatus using the same.

The present inventors have conducted intensive studies to solve the proposition of achieving both miniaturization and high durability when a conventional organic photoreceptor is combined with an electrophotographic process. The above object can be attained by providing an image forming apparatus characterized by having a contact charging or transfer system and a photosensitive member surface characteristic control function in addition to the charging or transfer function.

That is, by providing the contact charging or the transfer member with a plurality of functions, a device necessary for the original electrophotographic process and newly required around the electrophotographic photoreceptor for high durability can be provided. It is possible to reduce the number of devices and to secure a layout space for each device which is an obstacle to miniaturization.
In addition, by supplying a lubricating material for maintaining the surface characteristics of the photoconductor simultaneously with the application of an electric field for charging and transfer, deterioration of the photosensitive layer can be suppressed, and a highly durable image forming apparatus can be obtained. be able to.

When the photosensitive layer is scraped, the electrical characteristics (e.g., charging performance and light attenuating performance) of the photoconductor change, so that a predetermined image forming process cannot be performed and the quality of a hard copy as a final output is maintained. It becomes difficult.
In the electrophotographic process, this film abrasion occurs at all portions where the photoconductor and other image forming units come into contact with each other, but the most problematic unit is a cleaning unit () that dynamically removes toner remaining on the photoconductor. Blade or brush). Although there is some wear by other units, it does not significantly affect the real life.

Wear generated in the cleaning unit is mainly classified into two types. One is abrasion caused by the shearing force generated on the photoconductor and the blade (brush), and the other is abrasion wear where the toner acts like a grindstone when the toner is sandwiched between the blade (brush) and the photoconductor. It is.
Factors that determine these factors include the structural strength of the photoreceptor, the contact pressure of the cleaning blade (brush), the composition of the toner particles, and the surface friction coefficient (μ) of the photoreceptor. In particular, there is a large correlation between the shearing force at the contact portion between the photoconductor and the cleaning blade (brush), the photoconductor surface friction coefficient, and the amount of wear, and by keeping the photoconductor surface friction coefficient low, wear is suppressed to a small extent. It turns out that you can.

According to the present invention, the contact charging or contact transfer member is provided with a function of lowering the friction coefficient, which is the surface characteristic of the photosensitive member, to reduce the wear of the photosensitive layer caused by contact with the cleaning unit in a compact system. It becomes possible to decrease.

As is clear from the following detailed and specific description, the present invention can provide a compact, high-performance, and highly reliable image forming apparatus.

Hereinafter, the present invention will be described in detail with reference to the drawings.
1 to 12 show an example of a schematic cross-sectional view of an electrophotographic process having a multifunctional contact charging or transfer device of the present invention.
In FIG. 1, reference numeral (101) denotes a photosensitive drum which rotates in the direction of an arrow. Around the periphery, a contact charging device (102), an image exposure means (103) from an exposure device, a developing device (104), a contact transfer device An apparatus (106), a cleaning unit (107), a static elimination lamp (108), a fixing device (109), and the like are provided, and a transfer body (105) is supplied thereto.

Here, the image exposure means (103) is an analog image exposure for irradiating the reflected light of the copy original through a lens or a mirror, or an electric signal from a computer or the like, or an electric signal obtained by reading and converting the copy original by an image sensor such as a CCD. Any of digital image exposure for reproducing a signal or the like as an optical image by a laser beam, an LED array, or the like may be performed.

FIG. 2 is an enlarged view of an example of the contact charging device (102) shown in FIG. 1. The photosensitive member contact member of the elastic roller-shaped contact charging device (102a) has a material (111) for applying a charge. ) And a material (112) for controlling the surface characteristics of the photoconductor (101).

FIG. 3 is an enlarged view of another example of the contact charging member (102) of FIG. 1. The brush (102b) has a fiber (113) for applying a charge, and a photoconductor surface. The fiber (114) for controlling the characteristics is constituted by a plurality of kinds of fibers.

FIG. 4 shows that the contact charging member (102) of FIG. 1 is composed of a fiber (115) for applying a charge and a fiber (116) for controlling the surface characteristics of the photoreceptor. It is composed of a plurality of types of fibers.

FIG. 5 shows that the contact charging member (102) of FIG. 1 is composed of a felt-shaped charging member (102d), and the felt-shaped charging member has a fiber for applying charge and a fiber for controlling the surface characteristics of the photoreceptor. Are composed of a plurality of types of fibers.

FIG. 6 shows an embodiment of the contact charging member (106) of FIG. 1, in which the photosensitive member contact member of the elastic roller-shaped contact transfer device (106a) includes a material (117) for applying a charge, It is made of a material (118) for controlling the photoconductor surface characteristics.

FIG. 7 shows another embodiment of the contact charging member (106) of FIG. 1, in which the photoconductor contact member of the belt-shaped contact transfer device (106b) includes a material (119) for applying a charge and a material (119). And a material (120) for controlling the surface characteristics of the photoreceptor.

FIG. 8 shows an example in which a contact charging or transfer device (102) such as an elastic roller or the like (106) is provided with a device (130a) for supplying various powder materials for controlling the surface characteristics of the photoreceptor. is there.

FIG. 9 shows a contact charging or transfer device (102) or (106) such as an elastic roller impregnated with a sponge-shaped roller provided with a sustained release property with various liquid materials for controlling the surface characteristics of the photoreceptor. It is an example in which the device (130b) is added.

FIG. 10 shows an example in which a contact charging or transfer device (102) such as an elastic roller or the like (106) is provided with a device (130c) for contacting various solid materials for controlling the surface characteristics of the photoreceptor. It is a thing.

FIG. 11 shows a device (130b) for supplying various liquid materials to the contact charging or transfer device for controlling the surface characteristics of the photoreceptor, further provided with a mechanism for contacting and separating the fulcrum (140) with the force of a solenoid (141). FIG.

FIG. 12 shows a device (130c) for supplying various solid materials to the contact charging or transfer device for controlling the surface characteristics of the photoreceptor, further provided with a mechanism for contacting and separating the fulcrum (140) with the force of a solenoid (141). FIG.

Here, in general, the photosensitive member is moved while a member such as an elastic roller, a brush-like roller, an elastic blade, a brush, or a belt having appropriate conductivity is in contact with the surface of the photosensitive member. This is a device for applying a DC voltage of a polarity necessary for charging or transfer to the photoconductor to maintain a desired potential on the surface of the photoconductor or to transfer toner.

As a method for applying a charge or transferring a toner efficiently and uniformly and stably, a roller-shaped member is brought into contact with the surface of a photoreceptor at a linear velocity difference, or a contact voltage or a DC voltage applied to a transfer member. In order to overcome this problem, a contrivance is made to multiply a symmetric or asymmetric alternating electric field such as a sine wave or a pulse wave.

A first object of the present invention is to uniformly supply a material (lubricant or the like) to be supplied to the surface of the photoreceptor for controlling the surface characteristics of the photoreceptor, by using a brush-like roller, an elastic roller, a porous elastic member, or the like. Rollers, porous elastic blades, brushes, belts and the like are preferably used.

For the purpose of controlling the surface friction coefficient of the photoreceptor surface properties, a lubricant having various lubricating actions such as liquid, solid, powder, etc. may be used as the lubricant supplied to the photoreceptor surface via contact charging or a transfer member. it can.
That is, silicone oil, lubricating liquid such as fluorine oil, various fluorine-containing resins such as PTFE, PFA, PVDF, silicone resin, polyolefin resin, silicone grease, fluorine grease, paraffin wax, fatty acid metal salts such as zinc stearate, The object is achieved by supplying a lubricating solid or powder such as graphite or molybdenum dioxide to the surface of the photoreceptor by an appropriate method.

In such a contact charging or transfer device, appropriate resistance is required for the member, and when the photoreceptor is not elastically deformed in a drum shape, furthermore, if the surface of the photoreceptor does not elastically deform, the contact charging or transfer member is further charged. Appropriate elasticity is also required to ensure a sufficient contact area.

Organic polymer materials that are generally used as such elastic materials for contact charging or transfer devices include resin materials (plastomers) and rubber materials (elastomers). Specific examples thereof include polyvinyl chloride. , Polyvinyl resins such as polyvinyl butyral, polyvinyl alcohol, polyvinylidene chloride, polyvinyl acetate and polyvinyl formal; polystyrene resins such as polystyrene, styrene-acrylonitrile copolymer, acrylonitrile-butadiene-styrene copolymer; polyethylene, ethylene-acetic acid Polyethylene resin such as vinyl copolymer; acrylic resin such as polymethyl methacrylate, polymethyl methacrylate-styrene copolymer; polyacetal, polyamide, cellulose, polycarbonate, phenoxy resin Resin materials such as polyester, fluorine resin, polyurethane, phenol resin, urea resin, melamine resin, epoxy resin, unsaturated polyester resin, and silicone resin; natural rubber, isoprene rubber, butadiene rubber, styrene-butadiene rubber, ethylene-propylene rubber, Rubber materials such as chloroprene rubber, chlorinated polyethylene rubber, epichlorohydrin rubber, nitrile rubber, acrylic rubber, urethane rubber, polysulfide rubber, silicone rubber, fluorine rubber, and silicone-modified ethylene-propylene rubber are exemplified.

Examples of materials for imparting conductivity to these materials include metal powders such as Ni and Cu; carbon blacks such as furnace black, lamp black, thermal black, acetylene black, and channel black; tin oxide, zinc oxide, molybdenum oxide, and antimony oxide. Conductive oxides such as potassium, titanate and the like; electroless plating products plated on titanium oxide and mica; inorganic fillers such as graphite, metal fibers and carbon fibers, and surfactants. These conductivity-imparting agents are added when the organic polymer is insulative, but have a medium resistance (102 to 1012 Ω · cm) such as polyamide, epoxy rubber, epichlorohydrin rubber, nitrile rubber, acrylic rubber, and urethane rubber. It is not always necessary to add to organic polymers capable of forming a region.

Adjust the resistance to an appropriate value using the above materials and use it as an elastic member for contact charging or a transfer device. Instead of a single layer, a plurality of materials having different laminated structures and different resistance values are used in a mixed state as needed to improve the characteristics. As the material for the brush used in the contact charging or transfer device, synthetic or natural fibers having appropriate conductivity are used. Specific examples thereof include carbon black, carbon fiber, metal powder, metal oxide in resin fibers capable of forming fibers such as rayon, nylon, acetate, vinylidene, vinylon, polyurethane, polyester, polyethylene, polyvinyl chloride, and polypropylene. A material in which a resistance control agent such as a semiconductor material is dispersed or surface-coated is mainly used.

Next, the control method of the friction coefficient of the photosensitive member and its necessity will be described.
As described above, when the photoreceptor has a low friction coefficient by the above method, the photoreceptor abrasion amount can be reduced, but the photoreceptor surface friction coefficient is reduced to 0.4 or less by the Euler belt method. The effect is significant when maintained. On the other hand, when the friction coefficient is reduced more than necessary, as a problem, when the latent image is visualized by the developing unit, the adhesive force between the toner and the photoconductor is reduced, and the toner is not intended to be on the photoconductor. A phenomenon occurs in which transfer cannot be performed. These may occur particularly in a system in which a developer is developed while being in contact with a photoreceptor, such as two-component development. That is, when the developer spike, which is a feature of two-component development, comes into contact with the surface of the photoreceptor, a mechanical force is generated by the spike at the time of contact, and the toner transferred to the photoreceptor is scraped off again, Is displaced from the normal position, which causes this problem.

These phenomena hardly occur at the time when the friction coefficient of the surface layer of the photoreceptor is high, and remarkably occur when the surface friction coefficient becomes smaller than 0.1, for example, about 0.05 as measured by the Euler belt method. become. This defect is a fatal problem in hard copy quality, and in order to prevent the occurrence, it is necessary to control the application of additives so as not to lower the friction coefficient of the photoreceptor surface more than necessary.

物質 Also, various substances adhere to the photoreceptor at the stage of the process. The main ones are an oxidizing gas such as ozone, NOx, and SOx generated by charging and discharging in the transfer region, or an ionic compound generated by a complex reaction of these. These deposits are very hydrophilic, and when attached to the photoreceptor surface, they absorb or take in water molecules in the air, lower the electrical resistance of the photoreceptor surface layer, and the latent image drawn by optical writing The electric charge cannot be held due to the decrease in resistance, and the image is disturbed. However, these deposits are usually scraped off the photoreceptor by a cleaning blade or the like, and often do not cause an actual problem. However, if the friction coefficient between the photosensitive layer and the blade is reduced more than necessary, and the shearing force generated there is also reduced, it becomes difficult to remove these substances from the photoreceptor, and the above-described image defect occurs. Similar to the above-described development failure phenomenon, this disadvantage becomes remarkable when the photoreceptor surface friction coefficient becomes smaller than 0.1 as measured by the Euler belt method. In order to prevent these problems from occurring, it is necessary to control the application of an additive that changes the friction coefficient of the photoconductor surface layer.

The Euler belt method employed as a method for quantifying the photoreceptor surface friction coefficient in the present invention will be described below.
A belt-shaped measuring member obtained by cutting medium-thick high-quality paper so that the paper cutting direction is the longitudinal direction is brought into contact with a quarter of the outer periphery of the cylindrical photoreceptor surface, and a load (100 g) is applied to one (lower end) thereof. After the force gauge is connected to the other end, the force gauge is moved at a constant speed, and the value of the force gauge when the belt starts moving is read and calculated by the following equation.
μs = 2 / π × In (F / W)
Where μs: Coefficient of static friction F: Force gauge reading (g)
W: Load (100g)
The need for controls has been described above. In the present invention, as described above, it is an object of the present invention to provide a low-abrasion photoreceptor system which is a main object of the present invention, suppress abnormal images, and keep the images normal while providing the main object of the present invention.

Next, the present invention will be described more specifically with reference to examples, but the present invention is not limited to the following examples. All parts used in the examples are parts by weight.
Example Preparation of Photoreceptor for Evaluation On a 30 mm-diameter aluminum drum, a coating liquid for an undercoat layer, a coating liquid for a charge generation layer, and a coating liquid for a charge transport layer having the following composition were sequentially coated and dried. An undercoat layer of 3.5 μm, a charge generation layer of 0.2 μm, and a charge transport layer of 25 μm were formed to obtain an electrophotographic photoreceptor of the present invention.
[Coating liquid for undercoat layer]
Alkyd resin 6 parts (Veccosol 1307-60-EL, manufactured by Dainippon Ink and Chemicals, Inc.)
Melamine resin 4 parts (Super Beckamine G-821-60, manufactured by Dainippon Ink and Chemicals, Inc.)
Titanium oxide 40 parts Methyl ethyl ketone 200 parts [Coating liquid for charge generation layer]
2.5 parts of trisazo pigment having the following structure

　　ポリビニルブチラール（ＵＣＣ：ＸＹＨＬ）　　　　　　　　　　　０．２５部
　　シク口へキサノン　　　　　　　　　　　　　　　　　　　　　　　　２００部
　　メチルエチルケトン　　　　　　　　　　　　　　　　　　　　　　　　８０部
［電荷輸送層用塗工液］
　　ビスフェノールＡ型ポリカーボネート　　　　　　　　　　　　　　　　１０部
　　（帝人：パンライトＫ１３００）
　　塩化メチレン　　　　　　　　　　　　　　　　　　　　　　　　　　１００部
　　下記構造の低分子電荷輸送物質　　　　　　　　　　　　　　　　　　　１０部

Polyvinyl butyral (UCC: XYHL) 0.25 parts Silk mouth hexanone 200 parts Methyl ethyl ketone 80 parts [Coating liquid for charge transport layer]
Bisphenol A type polycarbonate 10 parts (Teijin: Panlite K1300)
100 parts of methylene chloride 10 parts of a low molecular charge transport material having the following structure

After mounting the electrophotographic photosensitive member manufactured as described above for mounting, it was mounted on the image forming apparatuses of the following Examples and Comparative Examples and evaluated.
[Evaluation method of actual running characteristics]
Each of the image forming apparatuses of Examples and Comparative Examples was subjected to a paper passing test of up to 100,000 sheets. During and after the paper-passing test, the potential characteristics of the photoreceptor, the image quality characteristics, the coefficient of friction of the photosensitive layer surface, and the amount of wear of the photosensitive layer were evaluated at appropriate times. The evaluation was started with the initial potential set to VD = 850 V and VL = 120 V for each sample.

Dark area potential (VD): Surface potential of photoconductor when moved to developing section after primary charging Light area potential (VL): Photosensitivity when moved to developing section after image exposure (solid exposure) after primary charging Body surface potential Image quality: Comprehensive evaluation of image density, fine line reproducibility, abnormal image, etc. Photosensitive layer surface friction coefficient (μs): Value based on Euler belt method Abrasion (Δd): Reduction of photosensitive layer thickness by actual machine running

Reference Example 1
As shown in FIG. 2, a contact charging device of the image forming apparatus having the structure shown in FIG. The image forming apparatus of Reference Example 1 was manufactured by replacing the charging roller with a rectangular shape, and a paper passing test was performed on up to 100,000 sheets.

Reference Example 2
As shown in FIG. 2, the contact charging device of the image forming apparatus having the configuration shown in FIG. 1 is an elastic roller-shaped charging roller made of a conductive elastic material (111) and silicon resin fine particles (Tospearl 120: manufactured by Toshiba Silicone) (112). The image forming apparatus of Reference Example 2 was manufactured, and a paper passing test was performed on up to 100,000 sheets.

Reference Example 3
As shown in FIG. 3, the contact charging device of the image forming apparatus having the configuration shown in FIG. 1 was replaced with a brush-shaped charging device composed of conductive fibers (113) and ethylene tetrafluoride resin fibers (114). The image forming apparatus of Example 3 was manufactured, and a paper passing test was performed on up to 100,000 sheets.

Reference Example 4
As shown in FIG. 4, the contact charging device of the image forming apparatus having the configuration shown in FIG. 1 was replaced with a brush roller type charging device comprising conductive fibers (115) and tetrafluoroethylene resin fibers (116). The image forming apparatus of Example 4 was manufactured, and a paper passing test was performed on up to 100,000 sheets.

Reference Example 5
As shown in FIG. 5, the contact charging device of the image forming apparatus having the configuration shown in FIG. 1 was replaced with a felt-shaped charging device composed of conductive fibers and tetrafluoroethylene resin fibers. And a paper passing test was performed on up to 100,000 sheets.

Example 1
As shown in FIG. 6, the contact transfer device of the image forming apparatus having the configuration shown in FIG. 1 has an elastic roller made of a conductive elastic material (117) and fluororesin fine particles (KTL-8N: manufactured by Kitamura Corporation) (118). The image forming apparatus of Example 1 was manufactured by replacing the transfer roller with the shape transfer roller, and a paper passing test was performed on up to 100,000 sheets.

Example 2
As shown in FIG. 7, the contact transfer device of the image forming apparatus having the configuration shown in FIG. 1 is made of a conductive material (119) and fluororesin fine particles (KTL-8N: manufactured by Kitamura Corporation) (120). The image forming apparatus of Example 2 was manufactured by replacing the transfer belt, and a paper passing test was performed on up to 100,000 sheets.

Reference Example 6
As shown in FIG. 8, the contact charging device of the image forming apparatus having the configuration shown in FIG. 1 is configured to supply fine ethylene tetrafluoride powder (Rublon L-2: manufactured by Daikin Industries, Ltd.) to the elastic roller charging roller. The image forming apparatus of Reference Example 6 was manufactured by exchanging the paper with the image forming apparatus, and a paper passing test was performed on up to 100,000 sheets.

Reference Example 7
As shown in FIG. 8, the contact charging device of the image forming apparatus having the configuration shown in FIG. 1 is replaced with an elastic roller-shaped charging roller provided with a mechanism for supplying fine silicon resin powder (KMP590: made by Shin-Etsu Silicone). The image forming apparatus of Reference Example 7 was manufactured, and a paper passing test was performed on up to 100,000 sheets.

Reference Example 8
As shown in FIG. 9, the contact charging device of the image forming apparatus having the configuration shown in FIG. 1 is configured such that the elastic roller-shaped charging roller is impregnated with silicone oil (KF50: manufactured by Shin-Etsu Chemical Co., Ltd.). The image forming apparatus of Reference Example 8 was manufactured by replacing the roller with the roller (130b), and a paper passing test was performed on up to 100,000 sheets.

Reference Example 9
As shown in FIG. 9, the contact charging device of the image forming apparatus having the configuration shown in FIG. 1 is gradually released by impregnating an elastic roller-shaped charging roller with fluorine oil (Demnum S-100, manufactured by Daikin Industries, Ltd.). The image forming apparatus of Reference Example 9 was manufactured by replacing the roller with the elastic roller (130b), and a paper passing test was performed on up to 100,000 sheets.

Reference Example 10
As shown in FIG. 10, the contact charging device of the image forming apparatus having the configuration shown in FIG. 1 is replaced with a brush roller-shaped charging member provided with a mechanism for bringing the plate-shaped tetrafluoroethylene resin (121) into contact therewith. Thus, an image forming apparatus of Reference Example 10 was manufactured, and a paper passing test was performed on up to 100,000 sheets.

Reference Example 11
In Reference Example 8, the change in the image formed on the photoreceptor with respect to the elastic roller-shaped charging roller using a sustained release elastic roller (130b) impregnated with silicone oil (KF50: manufactured by Shin-Etsu Chemical Co., Ltd.) The image forming apparatus of Reference Example 11 further provided with a contact / separation mechanism (140) and (141) based on the signal information of the sensor for detecting .

Reference Example 12
In Reference Example 9, an image formed on a photoreceptor is obtained by using a sustained release elastic roller (130b) impregnated with fluorine oil (Demnum S-100: manufactured by Daikin Industries, Ltd.) with respect to an elastic roller-shaped charging roller. The image forming apparatus of Reference Example 12 further provided with a mechanism (140) and a mechanism (141) for contacting / separating based on the signal information of the sensor for detecting the change of the sheet, and a paper passing test of up to 100,000 sheets was performed. Was.

Reference Example 13
In the tenth embodiment, the plate-like tetrafluoroethylene resin (121) is brought into and out of contact with the brush roller charging member in a timely manner based on signal information of a sensor that detects a change in an image formed on the photoconductor. The image forming apparatus of Reference Example 13 was manufactured by replacing the apparatus with a mechanism having a mechanism for causing the sheet to pass, and a paper passing test was performed on up to 100,000 sheets.

Reference Comparative Example 1
The contact charging device of the image forming apparatus in Reference Examples 1 and 2 is an elastic roller-shaped charging roller made of only the conductive elastic material (111), and the image forming apparatus of Reference Comparative Example 1 is manufactured. A paper passing test was performed.

Reference Comparative Example 2
The image forming apparatus of Reference Comparative Example 2 was manufactured by using the contact charging device of the image forming apparatus in Reference Example 3 as a brush-like charging device made of only the conductive fiber (113), and a paper-passing test of up to 100,000 sheets was performed. Done.

Reference Comparative Example 3
The contact charging device of the image forming apparatus in Reference Example 4 was a brush roller charging device made of only the conductive fiber (115), and the image forming apparatus of Reference Comparative Example 3 was manufactured. Was performed.

Reference Comparative Example 4
The contact charging device of the image forming apparatus in Reference Example 5 was replaced with a felt-shaped charging device consisting of only conductive fibers, and an image forming apparatus of Reference Comparative Example 4 was manufactured. Done.

Comparative Example 1
The image forming apparatus of Comparative Example 1 was manufactured by replacing the contact transfer device of the image forming device in Example 1 with an elastic roller-shaped transfer roller made of only the conductive elastic material (117). A paper test was performed.

Comparative Example 2
The contact transfer device of the image forming apparatus in Example 2 was replaced with a transfer belt whose surface material was made only of the conductive material (119), and an image forming apparatus of Comparative Example 2 was manufactured. The test was performed.

Table 1 shows the evaluation results of the examples, comparative examples, reference examples, and reference comparative examples. The criteria are as follows.
：: Very good ：: Good １ ： 1: Slight streak image generated △ 2: Slight image deletion occurred × 1: Streak image, background smear × 2: Image deletion occurred

As is clear from Table 1, the image forming apparatus of the present invention has little deterioration in electrical characteristics such as chargeability and photosensitivity of the photoreceptor for organic electrophotography, has very little abrasion of the photosensitive layer, and has high image quality. Can be obtained stably for a long period of time. Further, by controlling the photoconductor surface characteristic control amount based on signal information from a sensor that detects a change in an image formed on the photoconductor, this effect can be maintained for a longer period of time. On the other hand, the conventional image forming apparatus has a large decrease in the film thickness, the electrical characteristics and the image characteristics are greatly deteriorated in a short period of time, and is clearly inferior to the image forming apparatus of the present invention as a highly durable and highly reliable image forming apparatus. You can see that.

FIG. 1 is a schematic diagram illustrating an example of an image forming apparatus using the apparatus of the present invention. 1 is a cross-sectional view illustrating an example of a contact charging device to which the concept of a contact transfer device according to the invention is applied. FIG. 3 is a cross-sectional view showing another example of a contact charging device to which the concept of the contact transfer device of the invention is applied. FIG. 11 is a cross-sectional view illustrating still another example of the contact charging device to which the concept of the contact transfer device according to the invention is applied. FIG. 11 is a cross-sectional view showing still another example of the contact charging device to which the concept of the contact transfer device of the invention is applied. FIG. 2 is a cross-sectional view illustrating an example of the contact transfer device of the present invention. FIG. 4 is a cross-sectional view illustrating another example of the contact transfer device of the present invention. FIG. 4 is a cross-sectional view illustrating another example of the contact charging or transfer device of the present invention. FIG. 11 is a cross-sectional view showing still another example of the contact charging or transfer device of the present invention. FIG. 11 is a cross-sectional view showing still another example of the contact charging or transfer device of the present invention. FIG. 11 is a cross-sectional view showing still another example of the contact charging or transfer device of the present invention. FIG. 9 is a cross-sectional view showing still another example of the contact charging or transfer device of the present invention.

Explanation of reference numerals

Reference Signs List 101 photoconductor drum 102 contact charging device 103 image exposure means 104 developing device 105 transfer body 106 contact transfer device 107 cleaning blade 108 static elimination lamp 109 fixing device

Claims (16)

At least a transfer device used in an image forming process having a charge-image exposure-development-transfer-fixing-cleaning step, in which an electric field is applied by contacting an electrophotographic photosensitive member used in the image forming device. A contact transfer device which is a contact transfer device of a system and has a function of controlling a surface characteristic of a photoreceptor in addition to an original electric field application function. 2. The contact transfer device according to claim 1, further comprising a photoconductor surface friction coefficient control function as a photoconductor surface characteristic control function other than the electric field application function. 3. The contact transfer device according to claim 2, wherein the contact transfer device comprises a member for applying an electric field and a lubricating member for controlling the coefficient of friction of the surface of the photosensitive member. 4. The contact transfer device according to claim 3, wherein the contact transfer device comprises a conductive material for applying an electric field and a fluororesin material for controlling a surface friction coefficient of the photoconductor. The contact transfer device according to claim 4, wherein the contact transfer device is a brush-like structure made of a conductive fiber for applying an electric field and a fluororesin fiber for controlling a friction coefficient of the surface of the photoconductor. The contact transfer device according to claim 4, wherein the contact transfer device is a felt-like structure made of a conductive fiber for applying an electric field and a fluororesin material for controlling a surface friction coefficient of the photoconductor. 3. The photoreceptor according to claim 2, further comprising means for supplying a lubricating material for controlling the friction coefficient of the photoreceptor surface, wherein the supplying means supplies the lubricating material for controlling the friction coefficient of the photoreceptor surface to the surface of the photoreceptor. Contact transfer device. 8. The contact transfer device according to claim 7, wherein the lubricating material supplied to the photoconductor surface for controlling the friction coefficient of the photoconductor surface via the member for applying an electric field is a liquid. The contact transfer device according to claim 7, wherein the lubricating material supplied to the surface of the photoconductor for controlling the friction coefficient of the photoconductor surface via the member for applying an electric field is solid. 8. The contact transfer device according to claim 7, wherein the lubricating material supplied to the photoconductor surface for controlling the friction coefficient of the photoconductor surface via the member for applying an electric field is a fluororesin material. The contact transfer device according to any one of claims 2 to 10, wherein the coefficient of friction of the photoconductor surface is controlled to be 0.4 or less as measured by the Euler belt method. A mechanism for controlling the supply amount of the lubricating material for controlling the coefficient of friction of the photoconductor surface is provided, and the control of the application amount is performed by detecting a change in an image formed on the photoconductor. The contact transfer device according to any one of claims 7 to 10, wherein: The image change is detected as a development defect caused by a surface friction coefficient of the photoconductor being too low, and the detection is performed by a sensor or by judging an output image. The contact transfer device according to claim 12. The image defect is detected as image blurring or image deletion caused by an ionic compound attached to the photoreceptor, and the detection is performed by a sensor or by judging an output image. 13. The contact transfer device according to claim 12, wherein: An electrophotographic image forming apparatus comprising the contact transfer device according to claim 1. At least, in an electrophotographic image forming process having a charging-image exposure-development-transfer-fixing-cleaning step, a method of applying an electric field by contacting with an electrophotographic photoreceptor, in addition to the original electric field applying function, An electrophotographic image forming process using an electrophotographic image forming apparatus including a contact transfer device having a function of controlling the surface characteristics of the electrophotographic photosensitive member.

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