JP3016600B2 - Electrostatic recording device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charging device such as a charger, a transfer device, and other static elimination rolls in an electrostatic recording apparatus using an electrophotographic technique such as a copying machine, a printer, a facsimile, and a simple printing machine. It is.

[0002]

2. Description of the Related Art In an electrostatic recording apparatus using an electrophotographic method, such as a copying machine, a printer, and a facsimile, an electrostatic recording medium,
For example, a charger for charging an electrophotographic photosensitive member to form an electrostatic latent image, a transfer unit for transferring a toner image obtained by developing the latent image to a transfer material, and a static charger for the transferred electrostatic recording medium. In at least one of a static eliminator for separating an electrically attracted transfer material or a static eliminator for initializing an electrostatic recording medium by eliminating static charges remaining on an electrostatic recording medium after transfer Conventionally, a corona discharge device using a corona wire has been widely adopted.

[0003] However, corona discharge devices have a danger of applying a high voltage, require a highly insulated cable to prevent leakage, tend to be large and costly, and have a large portion of current. Flow to the shield electrode, the efficiency is low, the corona electrode generates a large amount of ozone, which is harmful to the human body, causes chemical changes in the material, and has a problem in durability. The corona wire to which is applied is likely to adhere dust in the air, causing wire contamination and causing problems such as image unevenness.

In recent years, a contact type charging device such as a roller type has been proposed to solve the above problems. However, the contact-type charging device causes a concentrated discharge to an electrically weak portion such as a pinhole existing in a photosensitive layer of an electrostatic recording medium such as an electrophotographic photosensitive member, which is an object to be charged, thereby causing uneven charging or contact. It is difficult to obtain physical uniformity and electrical uniformity on the surface of the type charging device due to processing, and unevenness due to these non-uniformities causes uneven charging. Since friction occurs, there is a problem in that the durability of the electrostatic recording medium is reduced, and it has been difficult to put it to practical use.

[0005]

DISCLOSURE OF THE INVENTION The present invention solves the above-mentioned conventional problems, and enables uniform charging to be performed even on an electrically weak portion of an electrostatic recording medium, thereby greatly improving durability. It is an object of the present invention to provide an electrostatic recording device having a contact type charging means which can be improved and has excellent reliability without uneven charging.

[0006]

SUMMARY OF THE INVENTION The present invention solves the above-mentioned problems by charging an electrostatic recording medium with a charger, forming an electrostatic latent image, and developing by a developing device to form a toner image. An electrostatic recording apparatus having a static elimination member for transferring to a material by the operation of a transfer unit and removing an electrostatic charge of toner remaining on the electrostatic recording medium after the transfer, wherein the charging unit, the transfer unit, and the static elimination member At least one is formed as a roll-shaped charging member, and the charging member has a shaft portion, a porous elastic layer provided on the shaft portion, and an elastic cylinder provided on the elastic layer. The problem is solved by an electrostatic recording apparatus characterized in that the elastic cylinder is made of Ni formed by electroforming. According to another aspect of the present invention, an electrostatic recording medium is charged by a charger, an electrostatic latent image is formed, and a developing device is used to form a toner image. The at least one of the charger and the transfer device is formed as a roll-shaped charging member, the charging member is a shaft, and a porous elastic member is provided on the shaft. It is proposed that the elastic layer has a body layer and an elastic cylinder provided on the elastic layer, and the elastic cylinder is made of Ni formed by electroforming.

[0007]

According to the present invention, since the roll-shaped charging member contacts and charges the electrostatic recording medium, and the portion of the roll-shaped charging member that contacts the electrostatic recording body is formed of an elastic cylinder, the electrostatic recording medium is formed by frictional contact. Deterioration and damage are prevented, and the life is increased. According to the present invention, a roll member having high accuracy and high smoothness was obtained, and uneven charging, transfer, and static elimination were prevented.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described based on an embodiment shown in the drawings.

In FIG. 1, an electrostatic recording member 1, for example, an electrophotographic photosensitive member is charged by a contact charger 2, an original image is exposed by an exposure optical system 3, and an electrostatic latent image is formed. To form a toner image, which is transferred by a transfer device 5 at a transfer position T to a transfer material P conveyed from a paper supply unit (not shown), and the transferred transfer material is fixed and discharged by a fixing device (not shown). After the transfer, the photoreceptor 1 is cleaned by the cleaning device 6, and the charge is removed by the erase lamp 7, and the next process from charging is repeated.

As the charger 2, a roll-shaped charging member, for example, a charging roll 2a is used. A DC bias voltage or an AC bias voltage superimposed on the DC bias voltage is supplied from a power source (not shown) to a potential suitable for the photosensitive member 1. Is applied. The charging roller 2a is provided with a cleaning member 2b that removes, for example, toner or the like that tends to adhere to the charging roller 2a, if necessary.

The exposure optical system 3 projects a slit-like image light 3a obtained by scanning an original (not shown) or a laser beam 3a modulated by an image signal onto the photoreceptor 1 via a mirror 3b and the like.

The developing device 4 has a developing roller 4a. The developing roller 4a conveys the toner 4b in the developing container to a developing position D to develop the electrostatic latent image on the photoreceptor 1 into a visible image. To form a toner image.

The transfer device 5 has a contact-type transfer roll 5a to which a bias voltage is applied, and transfers the toner image developed by the developing device 4 and after the operation of the pre-transfer charger 8 to the transfer material P. The transfer roller 5a is cleaned by the cleaning device 5b.

After the transfer by the transfer unit 5, the toner and the residual charge remaining on the photoconductor 1 are removed by the cleaning device 6, and the photoconductor 1 is initialized to be reusable. The cleaning device 6 includes a cleaning blade 6b and a toner guide roll 6a for guiding toner to be cleaned by the cleaning blade 6b into a cleaning container.
And a scraping plate 6C for scraping off the toner adhering to the toner guide roll 6a and transporting the toner into the container. A cleaning bias voltage is applied to the toner guide roll 6a to remove the toner, remove the static charge remaining on the electrostatic recording medium 1, and improve the cleaning performance of the toner by the cleaning blade 6b.

After the residual toner is completely removed by the cleaning blade 6b, the charge on the photosensitive member 1 is discharged,
To complete the initialization of the photoconductor 1, an erase lamp 7
Is provided.

In the above-described image forming process, a roll-type contact charging member is used for the charger 2 and the transfer unit 5. The toner guide roll 6a used in the cleaning device 6 has a function as a toner guide roll in addition to a function as a toner guide roll, and a function as a charge removing member for removing residual charges on the photoconductor.

Any one or all of the charging device 2, the transfer device 5, and the charge removing member, for example, the toner guide roll 6a having the charge removing function of the cleaning device 6, may be provided with a roll-type contact charging member, for example, a charge roll. A roll configured as in the reference example shown in FIG. 2 can be used.

In FIG. 2, a porous elastic layer 23 is fixed to the outer periphery of the shaft portion 21 by a convenient first adhesive 22 such as a double-sided adhesive tape. The porous elastic layer 23 is formed of an elastic foamed resin such as urethane foam or sponge rubber. An elastic cylinder 25 is fixed to the outer periphery of the porous elastic layer 23 by a second adhesive 24.

When the roll member 20 shown in FIG. 2 is used for any of the charger 2, the transfer unit 5, and the charge removing member 6a,
A DC or AC bias voltage is applied from a bias power supply (not shown) to perform charging, transfer, or charge elimination.
In this case, the application of the bias voltage is preferably performed through the shaft portion 21 in terms of reliability. Therefore, it is desirable that the shaft portion 21 is formed of a conductive material such as a metal and the porous elastic layer 23 is made conductive.

As a method for making the porous elastic layer 23 conductive, first, a conductive fine powder such as carbon black or metal fine powder is previously contained in a porous elastic material, and second, a vacuum deposition of metal is performed. Third, a method of coating the conductive fine powder on the surface of the porous elastic body by coating the surface of the porous elastic body with a dispersion of the conductive fine powder dispersed in a resin or a rubber material, for example, an RTV together with a solvent. , Drying and curing methods. Normally, the third method is used, but it is desirable to use a rubber material as a binder for the conductive fine powder so as not to impair the elasticity of the porous elastic body. As the rubber material, RTV and silicone rubber are convenient.

As the first adhesive 22, it is preferable to use a conductive adhesive. However, when a double-sided adhesive tape is used, a double-sided adhesive tape is used so that the free surface of the shaft portion 21 is partially exposed. It is convenient to provide

The roll member 20 used for the charger 2, the transfer unit 5, or the charge removing member 6a needs to have an extremely smooth surface so as to uniformly contact the surface of the electrostatic recording medium 1. If the smoothness is insufficient, uneven charging, uneven transfer, and uneven discharging occur, resulting in serious defects in the image. For this reason, an elastic cylinder 25 with a smooth surface having high accuracy is provided on the porous elastic layer 23. In this case, the second
It is desirable that the adhesive 24 is used for bonding and fixing.

As the second adhesive 24, an elastic material such as urethane rubber or silicon rubber is preferably used so as not to impair the elasticity of the roll member, but it is necessary to apply a bias voltage effectively. To make it possible,
Preferably, it is made conductive. As the second adhesive 24, a material containing conductive fine powder such as carbon black or metal fine powder in an elastic adhesive material such as urethane rubber or silicon rubber is used as the second adhesive 24 for the purpose of conductivity.

The surface of the roll member 20 has a uniform charge,
In order to perform transfer and static elimination, it is desirable to provide an electrode layer between the outermost surface layer and the elastic layer 23. However, if the second adhesive 24 is made conductive, the second adhesive 24 becomes an electrode layer. Can also be used.

In FIG. 2, the elastic cylinder 25 forms a surface layer and comes into contact with the electrostatic recording medium 1. Since the latent image carrying layer of the electrostatic recording medium 1, for example, the photosensitive layer of the electrophotographic photosensitive member is a thin film,
When a bias voltage is applied, concentrated discharge is likely to occur in an electrically weak portion. For this reason, on the surface layer of the elastic roll member 20, concentrated discharge to an electrically weak portion such as a pinhole of an electrostatic recording medium (latent image carrier) is prevented, and charging, transfer, and charge removal are efficiently performed. It is desirable to select a material having a specific resistance of 10 ³ Ωcm to 10 ¹² Ωcm so that it can be performed.

In the roll member 20 shown in FIG. 2, the material forming the elastic cylindrical body 25 as the surface layer has a specific resistance of 10 ³ Ωc.
A conductive fine powder such as carbon black is contained in a convenient amount, if necessary, so as to be m to 10 ¹² Ωcm. The elastic cylindrical body 25 having high accuracy and excellent flatness is obtained by applying a release material as needed on a cylindrical mold material having a smooth surface, and applying a heat-shrinkable tube made of a resin or rubber material to the mold material. After shrinking, the tube is pulled out of the mold and released from the mold to form a tube.

As the heat-shrinkable tube material, vinyl chloride,
It can be selected from a wide range of materials such as polyethylene, polyester, silicone rubber and the like. It is desirable to include a conductive or semiconductive fine powder such as carbon black in a convenient amount in the heat-shrinkable material. In order to provide favorable elasticity, the thickness of the elastic cylindrical body 25 depends on the material,
It is desirable to select from 0 to 500 μ.

The elastic cylindrical body 25 is formed by applying a resin or rubber material to a convenient thickness on a cylindrical mold having a smooth surface.
It can also be formed by solidifying with a solidifying means such as drying and hardening, and then releasing the mold material. As resin material, urethane resin, acrylic resin, polyester resin,
A wide selection can be made of epoxy resin, silicone resin, polyamide resin, polyimide resin, and the like. As the rubber material, urethane rubber, natural rubber, acrylic rubber, butyl rubber, chlorosulfonated polyethylene, silicon rubber, etc. can be widely used. By adding a convenient amount of conductive or semiconductive fine powder such as carbon black to these resin materials and rubber materials, it is possible to improve the charge, transfer and static elimination performance.

The elastic cylinder 25 thus formed
Is formed using a mold material having high dimensional accuracy and high smoothness, so that it can have excellent dimensional accuracy and a smooth flat surface, and achieve uniformity of charging, transferring, and discharging.

In order for the roll member 20 to obtain favorable elasticity as an elastic roll, the thickness differs from 20 to 500 μm in the case of a resin material and 50 to 1 in the case of a rubber material.
It is desirable that the film be formed to a thickness of 000μ.

The elastic cylinder 25 according to the present invention can be formed of a metal material formed by electroforming, for example, a Ni cylinder. In order to obtain favorable elasticity, it is desirable that the Ni electroformed cylinder be formed to have a thickness of 10 to 150 μm. In this case, concentrated electric discharge, uneven transfer, uneven static elimination occurs due to concentrated discharge in an electrically weak portion such as a pinhole of the electrostatic recording medium 1 having a large conductivity, or the life of the electrostatic recording medium is shortened. Therefore, as shown in FIG. 3, it is desirable to provide a dielectric layer 26 or a semiconductive layer 26 of 10 ³ Ωcm to 10 ¹² Ωcm on the surface of the elastic cylindrical body 25 of the roll member 20 ′.

[0032]

According to the present invention, the charging member is formed as an elastic roll member, and the elastic body comes into contact with the electrostatic recording medium, thereby preventing the electrostatic recording medium from being damaged and improving the charging efficiency. Promoted energy saving.

According to the present invention, uneven charging due to the occurrence of concentrated discharge in an electrically weak portion such as a pinhole of an electrostatic recording medium is prevented, and mechanical stimulus is greatly reduced even in frictional contact. Can increase the lifespan of the body,
A highly reliable electrostatic recording device was obtained.

According to the present invention, a charging member having high accuracy and high surface smoothness was obtained, and uneven charging, uneven transfer, and uneven discharging were prevented.

[Brief description of the drawings]

FIG. 1 is a schematic view of an example of an image forming apparatus utilizing the present invention.

FIG. 2 is a cross-sectional view illustrating a structure of a roll-shaped charging member as a reference example.

FIG. 3 is a sectional view showing the structure of an embodiment of a roll-shaped charging member according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electrostatic recording body 2 Charger 5 Transfer device 6 Cleaning device 6a Toner guide roll 21 Shaft 22 First adhesive 23 Porous elastic layer 24 Second adhesive 25 Elastic cylinder

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int. Cl. ⁷ , DB name) G03G 15/02-15/02 103 G03G 15/16-15/16 103 G03G 21/06

Claims (4)

(57) [Claims] An electrostatic recording medium is charged by a charger to form an electrostatic latent image, developed by a developing device to form a toner image, and transferred to a transfer material by an operation of a transfer device. In an electrostatic recording apparatus having a static elimination member for removing electrostatic charge of toner remaining on an electrostatic recording medium, the charging device, the transfer device,
At least one of the charge removing members is formed as a roll-shaped charging member, and the charging member is a shaft, a porous elastic layer provided on the shaft, and an elastic cylinder provided on the elastic layer. Wherein the elastic cylinder is made of Ni formed by an electroforming method. 2. An electrostatic recording apparatus in which an electrostatic recording medium is charged by a charger to form an electrostatic latent image, developed by a developing device to form a toner image, and transferred to a transfer material by an operation of the transfer device. In the above, at least one of the charging device and the transfer device is formed as a roll-shaped charging member, the charging member is a shaft portion, a porous elastic layer provided on the shaft portion, and Wherein the elastic cylinder is made of Ni formed by an electroforming method. 3. The elastic cylinder has a thickness of 10 to 150 μm.
The electrostatic recording device according to claim 1, wherein m is m. 4. The electrostatic recording apparatus according to claim 3, wherein a dielectric layer or a semiconductive layer is provided on a surface of the elastic cylinder.