JPH04240883A - Roller for electrophotographic device and production thereof - Google Patents

Abstract

PURPOSE:To provide the roller for an electrophotographic device which prevents the sticking of a toner, etc., and has stable characteristics and the process for producing this roller. CONSTITUTION:A cylindrical elastic material 22 is fixed to a central shaft 21 and a metallic material 23 is superposed and fixed onto the outer peripheral surface of this elastic material 22. A release material 24 is superposed and fixed onto the outer peripheral surface of this metallic material 23, by which the release material 24 is stuck to the outer peripheral side of the elastic material 22 without impairing the characteristics of this elastic material 22, by which the sticking of the toner, etc., to the outer peripheral surface of the roller is prevented.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a roller used, for example, as a transfer roller in an electrophotographic apparatus, and a method for manufacturing the same.

0002

[Prior Art] Electrostatic electrophotographic devices used in copying machines, facsimile machines, laser printers, etc.
A transfer roller is used as a transfer device that transfers the toner image onto the recording paper using electrostatic force by applying a charge to the recording paper with a polarity opposite to that of the toner image formed on the surface of the photoreceptor. There is a system in which a recording paper is conveyed while being held between a photosensitive drum and a transfer roller in direct contact with the photosensitive drum, and the transfer is performed by applying an electric charge to the transfer roller.

An electrophotographic apparatus using this transfer roller will be explained with reference to FIG. In the figure, 1 is a photosensitive drum, which is rotated by a rotating device (not shown). A charging device 2, an exposure device 3, a developing device 4, a cleaning device 5, and a static eliminating device 6 are arranged around the photoconductor drum 1 in the order of its rotational direction.
A developing device 4 and a cleaning device 5 are also provided.
A transfer roller is provided between the two. A conventional transfer roller has a structure in which a cylindrical elastic member 8 made of an electrically conductive foamed elastic material is fixed around a shaft 7 made of metal, and is rotated by a rotating device. Further, the transfer roller is connected to a power source via a conductive bearing or a slip ring to a metal central shaft 7. 9 is a paper feed roller, and 10 is a paper feed guide.

[0004] The process of forming an image will be explained. While the photosensitive drum 1 rotates in the direction of the arrow shown in the figure, the following occurs. The charging device 2 uniformly charges the surface of the photoreceptor drum 1. The exposure device 3 irradiates the surface of the photoreceptor drum 1 with an optical image signal to form an electrostatic latent image. The developing device 4 supplies toner T stored in a toner tank 11 to the surface of the photosensitive drum 1 through a developing sleeve 12, and visualizes the electrostatic latent image with the toner. Here, recording paper P is supplied from a paper feed cassette (not shown) and conveyed by rollers 9 and guides 10 between photosensitive drum 1 and transfer roller.

In the transfer roller, a voltage is applied to the center shaft 7 from a power source. An electric charge having a polarity opposite to that of the toner image is applied to the recording paper P from the back side of the recording paper P from the central shaft 7 via the elastic member 8. As a result, the toner image on the photosensitive drum 1 is transferred onto the recording paper P. Further, the recording paper P is conveyed to a fixing device (not shown) to fix the toner image thereon. On the other hand, the toner remaining on the photoreceptor drum 1 is removed by a cleaning device 5, and the charge remaining on the photoreceptor drum 1 is removed by a static eliminator 6. Image formation is performed by repeating this operation several cycles.

[0006] The reason why the elastic material 8 made of a foamed elastic material is used is that the elastic material 8 is soft, so that the nip width when the elastic material 8 contacts the surface can be increased, and when the elastic material 8 contacts the photoreceptor drum 1, the nip width can be increased. This is because the magnitude of pressure per unit area can be reduced. This increases the transfer time and increases the toner
This is because hollow images can be prevented and filming on the photoreceptor drum can be prevented.

[0007]

[Problems to be Solved by the Invention] Since the transfer roller performs transfer by sandwiching the recording paper P between the photoreceptor drum 1, when the recording paper P is not passing, the conventional transfer roller
Elastic material 8 is in direct contact with the surface of photoreceptor drum 1.

However, the surface of the foamed elastic material forming the elastic member 8 has many narrow recesses due to the presence of air bubbles. Therefore, if the elastic material 8 comes into contact with the surface of the photoreceptor drum 1 and toner remains on the surface of the photoreceptor drum 1, this toner will enter the recesses on the surface of the elastic material 8 and fill the recesses. fill in. The presence of toner in the elastic material 8 causes a change in the resistance value and deterioration of the elasticity of the transfer roller, which adversely affects the transfer performance.

The present invention has been made based on the above-mentioned circumstances, and it is an object of the present invention to provide a highly reliable roller for an electrophotographic device that prevents toner from adhering to the roller surface, and a method for manufacturing the same. With the goal.

0010

[Means for Solving the Problems] In order to achieve the above object, the roller for an electrophotographic apparatus of the present invention has a cylindrical elastic material fixed to the central shaft, and a metal material on the outer peripheral surface of the elastic material. The metal material is stacked and fixed, and a release material is stacked and fixed on the outer peripheral surface of the metal material.

The method for manufacturing a roller for an electrophotographic device according to the present invention also includes the steps of obtaining a first member having a cylindrical elastic material fixed to its center axis, and a step of obtaining a first member having a cylindrical elastic material fixed to the central axis thereof; a step of obtaining a second member in which release materials are stacked and fixed; and a step of combining the second member on the outside of the first member, and combining the elastic material of the first member and the metal material of the second member. The method is characterized by comprising a step of fixing the.

0012

[Function] The roller for an electrophotographic device of the present invention has a property that the release material provided on the outer periphery of the elastic material with a metal material in between has the property of refusing the adhesion of toner and paper powder. It is possible to prevent the adhesion of particles and maintain the necessary electrical characteristics as a roller for an electrophotographic device. The mold release material can be provided on the outer peripheral side of the elastic material by interposing a metal material.

[0013] In the method of manufacturing a roller for an electrophotographic device of the present invention, a release material that cannot be directly fixed to the surface of an elastic material is fixed to the outer circumferential surface of a metal material, and the metal material is attached to the outer circumferential side of the elastic material. By fixing, it is possible to easily obtain a roller for an electrophotographic device in which a mold release material is present on the outer peripheral surface of the roller.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The drawings showing an embodiment of the present invention will be explained below. The roller of this embodiment is used as a transfer roller in an electrophotographic apparatus as shown in FIG. 4, and has the structure shown in FIG.

In the figure, 21 is a central shaft, and 22 is a cylindrical elastic member fixed to the central shaft 21. The central shaft 21 is made of a conductive metal such as iron or aluminum. The elastic material 22 is made of an open-cell foamed synthetic resin having conductivity, such as silicone resin or urethane resin. The degree of conductivity of the elastic material 22 varies depending on the degree of conductivity of the mold release material 24, with a resistance value in a range of approximately 107 Ω·cm or less, or in a range exceeding approximately 107 Ω·cm and up to 1012 Ω·cm. Select and set. The diameter of the elastic material 22 is large enough to allow stable contact with the surface of the photoreceptor drum 1. An example of a method for fixing the elastic material 22 to the central shaft 21 is integral molding.

Reference numeral 23 denotes a cylindrical metal material fixed to the outer peripheral surface of the elastic member 22, and 24 is a mold release material fixed to the outer peripheral surface of the metal material 23. The metal material 23 is made of a conductive metal such as aluminum or nickel. The thickness of the metal material 23 is several tens of μm. Metal material 2
3 to the outer circumferential surface of the elastic material 22 include an adhesive method,
Examples include the press-in method.

The mold release material 24 is made of an organic material having mold releasability, such as a fluorine-based compound or a silicon-based compound. The thickness of the mold release material 24 is several tens of micrometers to several hundred micrometers. The method for fixing the mold release material 24 to the outer peripheral surface of the metal material 23 is as follows:
Firstly, the cylindrical mold release material 24 is made into a thin film and fixed to the surface of the metal material 23 by adhesion or heat shrinkage.The second method is to apply the mold release material 24 electrostatically to the surface of the metal material 23 to form a film. The third method of forming and fixing the metal material 23 is to apply a liquid mold release material 2 to the metal material 23.
There is a method in which the mold release material 24 is attached and fixed by immersing the mold in 4.

The conductivity of the mold release material 24 will be explained. The degree of conductivity of the mold release material 24 is determined in combination with the degree of conductivity of the elastic material 22. In this embodiment, voltage is applied along a path from the central axis 21 to the elastic material 22 and the metal material 23, and since the elastic material 22 is electrically conductive, the mold release material 24 is electrically conductive, semiconductive, or insulating. It can be either gender.

[0019] In the thus constructed transfer roller,
The reason for using the elastic material 22 is to make the entire roller stably contact the surface of the photoreceptor drum as a base body of the roller. The use of a foamed elastic material for the elastic material 22 is also for the reasons previously discussed. The reason for using the mold release material 24 is to prevent toner and paper dust from adhering to the outermost surface of the roller.

The reason for using the metal material 23 is that the elastic material 22
and to apply a charge to the photoreceptor drum in response to the voltage from the elastic material 22. The main reason for using the metal material 23 is to enable the formation of a thin film of the mold release material 24 on the outer peripheral side of the elastic material 22. That is, in the method of forming the first cylindrical mold release material 24 into a thin film and fixing it to the surface of the metal material 23 by adhering or heat shrinking, the mold release material 24 is soft and does not have self-supporting properties. This is because the release material 24 is placed on the outside of the metal material 23 to maintain a raised cylindrical shape, and the mold release material 24 is bonded or heat-shrinked to the metal material 23 in this form. Elastic material 22
has elasticity, and since the surface has irregularities due to foaming, the thin film release material 24 cannot be adhered to the surface of the elastic material 22. Furthermore, since the elastic material 22 is deformed by heat, it is not possible to heat the elastic material 22 to cause the mold release material 24 to shrink due to heat.

In the method of electrostatically coating and fixing the release material 24 on the surface of the second metal material 23, the elastic material 22 cannot be directly electrostatically coated, but the metal material 23 cannot be electrostatically coated directly. This is because it is possible to perform electrocoating.

In the method of immersing the third metal material 23 in a liquid mold release material to adhere and fix the mold release material, the elastic material 2
This is because metal material 23 absorbs liquid mold release material and cannot be subjected to the dipping method, but metal material 23 can be subjected to the dipping method. Furthermore, this is because the metal material 23 can be fitted into the elastic material 22 and fixed to the elastic material 22 without impairing the physical properties and electrical characteristics of the elastic material 22. Next, an example of a method for manufacturing this transfer roller will be explained with reference to FIGS. 1 to 3.

First, as shown in FIG. 2, a cylindrical elastic material 22 is combined with a central shaft 21, this assembled body is placed in a mold, and the two are integrated by pressure heating to obtain a first member. .

Further, as shown in FIG. 3, a mold release material 24 is fixed to the outer peripheral surface of the cylindrical metal material 23 to obtain a second member. The method of fixing the mold release material 24 to the outer circumferential surface of the metal material 23 is, firstly, by making a cylindrical mold release material 24 into a thin film and bonding it to the surface of the metal material 23 by adhering it or heat shrinking it, and secondly, by fixing it to the surface of the metal material 23. A third method is to immerse the metal material 23 in a liquid mold release material 24 to adhere and fix the mold release material 24 on the surface of the metal material 23. Can be mentioned.

Next, as shown in FIG. 1, the metal material 23 to which the mold release material 24 is fixed is fitted to the outer circumferential side of the elastic material 22 fixed to the central shaft 21, and the metal material 23 is glued or press-fitted into the elastic material 22. The outer circumferential surface of the elastic material 22 and the inner circumferential surface of the metal material 23 of the second member are fixed together.

By this manufacturing method, it is possible to easily manufacture a transfer roller in which the mold release material 24 is provided on the outer circumferential side of the elastic material 22 without impairing the physical properties and electrical characteristics of the elastic material 22. In this embodiment, it is used as a transfer roller as shown in FIG. In FIG. 4, the same parts as in FIG. 5 are given the same reference numerals.

The transfer roller contacts the outer peripheral surface of the photosensitive drum 1 by utilizing the elasticity of the elastic material 22. Also, the transfer roller
The center shaft 21 of the roller is connected to a power source via a slip ring or a conductive bearing.

When performing transfer, the transfer roller, together with the photosensitive drum 1, nip and convey the recording paper P. Further, a voltage is applied from the power source to the central shaft 21 of the transfer roller, and an electric charge is applied to the recording paper P via the elastic material 22, the metal material 23, and the release material 24. As a result, the toner image on the photosensitive drum I is transferred onto the recording paper P.

When the recording paper P is not passing through, the outer peripheral surface of the release material 24 of the transfer roller comes into contact with it. Toner may remain and adhere to the surface of the photosensitive drum 1, or paper dust generated from the recording paper P may adhere. However, mold release material 2
No. 4 has the property of refusing to adhere to toner or paper dust. Therefore, even if the surface of the release material 24 comes into contact with the surface of the photoreceptor drum 1, toner and paper powder adhering to the surface of the photoreceptor drum 1 will not remain attached to the surface of the release material 4. do not have. Therefore, the occurrence of a situation in which toner or paper powder exists on the surface of the photoreceptor drum 1 changes the resistance value of the elastic material 22 or deteriorates the elasticity of the elastic material 22, resulting in deterioration of transfer performance, is avoided. It can be prevented.

[0030] As described above, the elastic roller does not change the mechanical properties or electrical properties of the elastic material 22 due to the provision of the mold release material 24, so good transfer can be achieved under preset necessary conditions. It can be performed.

The transfer roller of the above-mentioned example has a conductive path extending from the central shaft 21 to the elastic material 22, the metal material 23, and the mold release material 24. In addition, it is also possible to manufacture a transfer roller in which the central shaft 21 and the elastic material 22 are not passed through, and a voltage is applied to the metal material 23 from a power source to form a conductive path from the metal material 23 to the mold release material 24. In this case, the mold release material 24 may be insulating because the charge can be strongly applied to the photosensitive drum 1 from the metal material 23. Further, the center shaft 21 may also be made of an insulating material.

The present invention can achieve great effects when applied to a transfer roller, but is not limited to this application and can also be applied to other rollers installed and used in electrophotographic devices. be able to.

[0033]

As explained above, according to the present invention, since the mold release material is provided on the outer circumferential side of the elastic material through the metal material, it is possible to release the mold without impairing the mechanical and electrical properties of the elastic material. It is possible to provide a roller for an electrophotographic device that prevents toner and paper dust from adhering to the outer circumferential surface of the roller and has constant transfer performance and excellent reliability.

Further, according to the present invention, a first member in which a cylindrical elastic material is fixed to the central axis and a second member in which a release material is layered and fixed to the outer peripheral surface of a cylindrical metal material are combined. As a result, it is possible to easily manufacture a roller for an electrophotographic device that can prevent toner and paper dust from adhering to the outer peripheral surface of the roller without impairing the mechanical and electrical properties of the elastic material.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing one embodiment of a roller of the present invention.

FIG. 2 is a sectional view showing a member manufactured in the first step of the roller manufacturing method of the present invention.

FIG. 3 is a sectional view showing a member manufactured in the second step of the roller manufacturing method of the present invention.

FIG. 4 is a schematic diagram of an electrophotographic apparatus incorporating the roller of the present invention.

FIG. 5 is a schematic diagram of an electrophotographic apparatus incorporating a conventional roller.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1... Photoreceptor drum, 21... Central shaft, 22... Elastic material, 23
...Metal material, 24...Mold release material.

Claims (2)

[Claims] Claim 1: A cylindrical elastic material is fixed to the central axis, a metal material is overlapped and fixed to the outer peripheral surface of this elastic material, and a mold release material is overlapped and fixed to the outer peripheral surface of this metal material. Characteristic rollers for electrophotographic equipment. 2. Obtaining a first member in which a cylindrical elastic material is fixed to the central axis; obtaining a second member in which a release material is layered and fixed on the outer peripheral surface of a cylindrical metal material; An electronic device characterized by comprising the steps of combining the second member on the outside of the first member and fixing the elastic material of the first member and the metal material of the second member. A method of manufacturing a roller for photographic equipment.