JPH09297512A - Roller and its production - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a smooth roller whose hardness is low, whose elastic layer has high cell density and which has no fuzz by including a stage for press-fitting the roller so that the elastic layer of the roller may be compressed, a stage for heating the outer periphery of a cylindrical member and a stage for taking out the roller from the cylindrical member. SOLUTION: The roller 1 is press-fit is the cylindrical member 4 whose inside diameter is smaller than the outside diameter of the roller 1 so as to compress the elastic layer. Next, the outer periphery of the cylindrical member 4 is heated in a state where the roller 1 is inserted in the member 4. Finally, it is cooled after finishing heating, the roller 1' is taken out from the member 4. Since the cell being a foaming body has shape compressed in the radial direction of the roller, the roller is smooth all over the area of the elastic layer and holds the low hardness, while the number of cells on the surface of the elastic layer is larger than the number of cells inside the elastic layer, so that the surface is prevented from being clogged with the developer. By adjusting the inside diameter of the member 4 and the maximum thickness of the elastic layer before press-fitting, the hardness of the roller is freely changed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a developer carrying roller, a charging roller, a transfer roller, a developing roller in an electrophotographic apparatus such as a copying machine or a printer or an electrostatic recording apparatus.
The present invention relates to a roller such as a cleaning roller and a paper feed roller, and a method for manufacturing the same.

[0002]

2. Description of the Related Art In recent years, with the progress of electrophotographic technology, a developer conveying roller, a charging roller, a transfer roller, a developing roller, a cleaning roller, and a paper feeding device in an electrophotographic apparatus such as a copying machine or a printer, or an electrostatic recording apparatus. High requirements are also imposed on rollers such as rollers.

Further, the improvement in electrophotographic technology largely contributes to various improvements to the developer, and the developer is supplied to the electrostatic latent image formed on the latent image holding member such as the photosensitive drum to provide the electrostatic latent image. There is also a need for an improvement to the developer supply roller located in the developing device that visualizes the latent image.

Generally, a developer is supplied onto a latent image holding member such as a photosensitive drum which holds the electrostatic latent image, and the developer is attached to the electrostatic latent image on the latent image holding member to form the electrostatic latent image. The developing method for making the toner visible is a powder cloud method in which the developer particles are sprayed, a contact developing method in which the developer particles are brought into contact with the latent image surface of the photosensitive drum for development, and the developer particles are charged and electrostatically charged. Development methods such as a jumping development method that develops without contacting the latent image surface of the photosensitive drum by the electric field of the latent image and a magnetite method that develops by contacting a conductive developer having magnetism with the electrostatic latent image surface Are known. Here, the conveyance of the developer will be briefly described. For example, the developer filled in the developing device is supplied to the surface of the developing roller by the developer supply roller, and the developer is adjusted into a uniform thin layer by the blade. In this state, the developing roller rotates while contacting or approaching the photosensitive drum, so that the developer adheres to the electrostatic latent image on the photosensitive drum from the developing roller, and the latent image becomes visible. .

The following characteristics (1) to (5) are required for the developer supply roller used in such a developing device. Characteristic 1 Secure the nip width between the developer supply roller and the developing roller,
Secure a sufficient amount of developer to be conveyed, that is, the elastic layer has low hardness and its surface is smooth. Characteristic 2 To increase the cell density on the surface of the developer supply roller so that the surface of the developer is not clogged with the developer. Characteristic 3 To prevent bleeding on the surface of the developer supply roller and prevent foreign matters such as foam from entering the developing device.

Further, the conventional developer supply roller uses various foams such as rubber or resin for its elastic layer. Examples of the manufacturing method thereof include the following. Manufacturing Method 1 A method in which a shaft made of metal or resin is coated with an adhesive or the like as necessary, an elastic layer made of a foam is arranged on the outer periphery of the shaft, and then a desired roller shape is polished. A method in which the surface of a roller having an elastic layer arranged on the outer periphery of the shaft is processed with a hot wire as in the manufacturing method 2. Manufacturing method 3 A method in which a shaft is placed in advance in a mold and a material such as rubber or resin is injected into the cavity to obtain a roller.

[0007]

However, the conventional methods 1 to 3 for manufacturing the developer supply roller have the following drawbacks. The developer supply roller obtained by the manufacturing method 1 has the characteristics 1
If the elastic layer is made to have a low hardness in order to obtain the above, a large amount of fluffing will occur on the surface of the elastic layer when it is polished, so that the above property 3 cannot be satisfied. The developer supply roller obtained by the manufacturing method 2 has the characteristic 3 described above.
However, it is difficult to finish it uniformly in the circumferential direction of the roller, and the surface is burnt to increase the hardness of the surface, so that the above characteristic 2 cannot be satisfied. The developer supply roller obtained by the manufacturing method 3 has the above characteristic 1
However, since it is difficult to adjust the foaming state inside the mold, the above characteristic 1 cannot be satisfied.

Therefore, the present invention has been made in view of the above circumstances, and provides a smooth roller having a low hardness, a high cell density on the surface of its elastic layer, and no fluffing, and a method for manufacturing the same. With the goal.

[0009]

A roller according to claim 1 of the present invention is a roller having an elastic layer made of foam, wherein cells of the foam have a shape compressed in a radial direction of the roller. And the number of cells on the surface of the elastic layer is larger than the number of cells inside thereof.

A method for manufacturing a roller according to a second aspect of the present invention is a method for manufacturing a roller having an elastic layer made of foam, in which the elastic layer of the roller is pressed into a cylindrical member so as to be compressed. And a step of heating the outer periphery of the cylindrical member, and a step of taking out the roller from the cylindrical member.

A method for manufacturing a roller according to a third aspect of the present invention is characterized in that the foam is a urethane foam.

A method of manufacturing a roller according to a fourth aspect of the present invention is characterized in that the roller is a developer carrying roller for carrying a developer.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The inventors of the present invention have made extensive studies as to the method for producing a roller for the above problems, and as a result, in the method for producing a roller having an elastic layer made of foam,
By including the step of press-fitting the elastic layer of the roller into the cylindrical member so as to compress it, the step of heating the outer periphery of the cylindrical member, and the step of taking out the roller from this cylindrical member, the hardness of the roller is low. The present inventors have completed the present invention by finding that the surface of the elastic layer has a high cell density and a smooth roller free of fluffiness can be obtained.

In the roller of the present invention, since the cells of the foam are compressed in the radial direction of the roller, the cells on the surface of the elastic layer are kept smooth and have low hardness over the entire area of the elastic layer. Since the number is larger than the number of cells in the inside, the developer can be prevented from clogging the surface. Further, the hardness of the roller can be freely changed by adjusting the inner diameter of the cylindrical member and the maximum thickness of the elastic layer before being press-fitted into the cylindrical member.

The roller and the manufacturing method thereof according to the present invention will be described below in more detail with reference to the drawings. FIG. 1 is a schematic view showing an example of the roller manufacturing method of the present invention. First, FIG. 1A shows a roller 1 having an elastic layer 3 on the outer circumference of a shaft 2 in advance. Further, an adhesive layer (not shown) between the shaft 2 and the elastic layer 3 may be provided if necessary.
Further, here, the elastic layer 3 is illustrated as a roller shape in advance, but in some cases, it may be a polygonal shape obtained by cutting out a block of foam.

Next, FIG. 1B shows a step of compressing the elastic layer by press-fitting the roller of FIG. 1A into a cylindrical member 4 having an inner diameter smaller than the outer diameter of the roller. Here, the cylindrical member 4 is not particularly limited, and for example,
Examples of the pipe include metal and / or resin pipes. Since the elastic layer is thermally compressed by heating the shaft 2 and the cylindrical member 4 as described later, aluminum, copper, or the like having good thermal conductivity, A metal such as iron is preferable, and its inner surface can be coated with a material such as fluorine so that it can be easily press-fitted. Further, the inner diameter of the cylindrical member 4 is not particularly limited, and can be appropriately changed depending on how much the elastic layer to be inserted is compressed from the viewpoint of the hardness of the target roller and the like. When the thickness is 100, the thickness of the elastic layer in the obtained roller is 50 to 95.
It is preferable to set it to be about%. further,
The means for press-fitting is not particularly limited, and a known method can be used.

Next, FIG. 1C shows a step of heating the outer periphery of the cylindrical member 4 with the roller 1 inserted in FIG. 1B. Here, the heating method is not particularly limited, and a known method can be used. The heating temperature is not particularly limited and may be appropriately changed depending on the material of the foam used, but in the case of urethane foam, it is preferably 150 to 250 ° C.

Finally, FIG. 1D shows a step of taking out the roller 1 ′ from the cylindrical member 4 after being cooled after the heating in FIG. 1C is completed.

Next, the roller 1'obtained through the above steps will be described. FIG. 2 is a cross-sectional view taken along the line AA in FIG. 1D, in which the cells of the foam have a shape compressed in the radial direction of the roller, and the number of cells on the surface of the elastic layer is It is shown that there are more than the number of cells. The radial direction in the present invention is the direction shown by the arrow in FIG. The characteristics of the obtained roller 1'are as follows.・ Hardness [Asker C hardness]: 10 to 70 ° ・ Number of cells: 1.05 to 3.0 inside the elastic layer surface
The surface of the elastic layer referred to in the present invention means a portion 1 mm from the surface regardless of the outer diameter of the roller.

The shaft 2 according to the present invention is not particularly limited, and examples thereof include metal and resin. However, in the case of a resin shaft, conductivity may be imparted depending on the purpose.

The material suitable for the elastic layer 3 according to the present invention is not particularly limited, but examples thereof include thermoplastic foams or urethanes such as polyethylene, polyvinyl chloride, polystyrene, polyvinyl alcohol, viscose, and ionomer.
Thermosetting foams such as rubber foam, epoxy, phenol urea, pyranyl, silicone and acrylic are mentioned, but urethane is particularly preferable. The cell shape of the elastic layer 3 may be either a single cell or an open cell, but the open cell is preferable because the dimensional change due to temperature is less.

When the elastic layer 3 is made of urethane, the polyol is not particularly limited, and any hydrophobic or hydrophilic polyol can be used. From the viewpoint, polyester polyol or polyether polyol is preferable. The isocyanate is not particularly limited and known ones can be used.

As a conductive material for imparting conductivity to the elastic layer 3, firstly exemplified by powder, conductive carbon such as Ketjenblack EC, acetylene black, SAF, ISAF, HAF, FEF, GPF. , SR
Carbon for rubber such as F, FT, MT, carbon for color (ink) that has been subjected to oxidation treatment, pyrolytic carbon, natural graphite, artificial graphite, antimony-doped tin oxide, titanium oxide, zinc oxide, nickel, copper, Examples thereof include metals such as silver and germanium, metal oxides, and conductive polymers such as polyaniline, polypyrrole, and polyacetylene. Among them, carbon black is inexpensive and whose conductivity can be easily controlled with a small amount. Usually, the blending amount of these conductive materials is suitably used in the range of 0.5 to 50 parts by weight, particularly 1 to 30 parts by weight, based on 100 parts by weight of urethane.

Examples of ion conductive substances include sodium perchlorate, lithium perchlorate, calcium perchlorate,
Inorganic ionic conductive material such as lithium chloride, further tridecylmethyldihydroxyethylammonium perchlorate, lauryltrimethylammonium perchlorate,
Modified aliphatic dimethylethylammonium ethosulfate, N, N-bis (2-hydroxyethyl) -N-
(3′-dodecyloxy-2′-hydroxypropyl) methylammonium ethosulfate, 3-lauramidopropyl-toeimethylammonium methylsulfate, stearamidopropyldimethyl-β-hydroxyethyl-ammonium-dihydrogen phosphate, tetrabutyl Quaternary ammonium perchlorates such as ammonium borofluoride, stearyl ammonium acetate, lauryl ammonium acetate, sulfates,
Examples thereof include organic ionic conductive substances such as ethosulfate salt, methylsulfate salt, phosphate, borofluoride and acetate, or charge transfer complex. Usually, the compounding amount of these conductive materials is suitably used in the range of 0.0001 to 50 parts by weight with respect to 100 parts by weight of urethane.

[0025]

EXAMPLES The present invention will be described below with reference to examples, but the present invention is not limited thereto. (Example) An elastic layer of 210 mm in length and 6 mm in thickness (material: polyurethane foam [polyol: ester system], hardness [Asuka-C hardness] 15 °, number of cells 50 on the outer periphery of a shaft having a length of 250 mm and a diameter of 6 mm. A roller having a number of pieces / inch) was prepared.

This roller has a length of 250 mm and an inner diameter of 15.
It was press-fitted into a 5 mm pipe (material: aluminum), heated at 185 ° C. for 30 minutes using a heating furnace as a heating means, and after cooling at room temperature, a roller having an outer diameter of 15 mm was obtained.
The hardness of the obtained roller [Asker-C hardness] was 16 °, the number of cells on the surface was 150 cells / inch, and the number of cells inside was 60 cells / inch.

Next, in order to evaluate the performance of this roller as a developing / supplying roller, the evaluation was carried out by incorporating it into an image forming apparatus and using an actual machine. After printing 2000 sheets, no foreign matter such as foam was found in the developing apparatus. It was confirmed that a sufficient developer transport amount was secured.

[0028]

As described above, according to the present invention,
In a method for manufacturing a roller having an elastic layer made of foam, a step of press-fitting the elastic layer of the roller into a cylindrical member, a step of heating the outer periphery of the cylindrical member, and a step of rolling the roller from the cylindrical member. By including the step of taking out, a roller having a low hardness, a high cell density on the surface of the elastic layer, and a smooth roller free of fluffiness can be obtained.

[Brief description of drawings]

FIG. 1 is a schematic view illustrating an example of a method for manufacturing a roller of the present invention.

FIG. 2 is a schematic sectional view showing an example of a roller of the present invention.

[Explanation of symbols]

 1, 1'roller 2 shaft 3 elastic layer 4 cylindrical member

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁶ Identification code Office reference number FI technical display area B29K 75:00 105: 04

Claims (4)

[Claims] 1. A roller having an elastic layer made of foam, wherein cells of the foam have a shape compressed in the radial direction of the roller, and the number of cells on the surface of the elastic layer is within the range. Roller characterized by more than the number of cells. 2. A method for manufacturing a roller having an elastic layer made of foam, the step of press-fitting the elastic layer of the roller into a cylindrical member, the step of heating the outer periphery of the cylindrical member, and the cylinder. And a step of taking out the roller from the strip-shaped member. 3. The method of manufacturing a roller according to claim 2, wherein the foam is urethane foam. 4. The developer carrying roller for carrying the developer, wherein the roller is a developer carrying roller.
The method for manufacturing a roller described in [1].