JPH10228187A - Production of toner image transfer roll and toner image transfer roll - Google Patents

Abstract

PROBLEM TO BE SOLVED: To produce a toner image transfer roll having low hardness, satisfactory flatness and no unevenness in surface electric conductivity, hardness, etc., as an elastic transfer roll with a resin layer on the surface and simplifying producing process. SOLUTION: When an elastic layer 42 of electrically conductive rubber and an electrically conductive resin layer 43 are successively laminated on the periphery of a core metal 41 to produce a toner image transfer roll, an elastic layer 42 of electrically conductive foamed ethylene-propylene-diene rubber is formed on the periphery of the core metal 41, the resultant elastic roll is coated with an electrically conductive chlorinated PE resin tube and the rubber and resin are fused by heating the roll.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a toner image transfer roller, and more particularly, to a toner image transfer roller used for transferring a powder toner image developed in an electrophotographic apparatus onto a transfer sheet, and a method of manufacturing the toner image transfer roller. About.

[0002]

2. Description of the Related Art In a conventional electrophotographic apparatus, an electronic latent image formed on a photoreceptor is developed by powder toner.
Although a powder toner image is obtained, a corona transfer method has been mainly used for transferring the toner image onto a transfer sheet. In this method, a corona charge having a polarity opposite to that of the toner is applied from the back of the transfer paper in contact with the toner image, and the transfer paper is electrostatically attracted to the photosensitive member and the toner is simultaneously moved onto the transfer paper. Is widely used because it is simple and can perform uniform transfer. However, such a corona transfer method requires a separate separating means to separate the transfer paper electrostatically adsorbed on the photoconductor from the photoconductor, and also has a health problem because ozone is generated by corona discharge. .

Therefore, recently, a roller transfer method has been widely used in place of the corona transfer method. In this roller transfer method, as shown in FIG. 2, the transfer paper 8 is brought into contact with the photoreceptor 1 by pressing an elastic roller 4 from behind the transfer paper 8, and at the same time, a voltage having a polarity opposite to that of the toner is applied to the roller 4. To transfer the toner onto the transfer paper 8. This method has the advantage that there is no generation of ozone, the transfer paper is hardly charged, the separation from the photoconductor is easy, and the image quality is good because the transfer paper and the photoconductor are in close contact with each other.

In the roller used in such a roller transfer method, since the elastic layer needs to have conductivity, foaming of ethylene propylene diene (EPDM) rubber or urethane rubber blended with carbon black or the like as a conductivity-imparting agent is required. In many cases, the body is an elastic layer. However, if the surface of the roller is a foam, cleaning of the adhered toner tends to be inadequate, and there is a problem that the transfer paper is stained on the back side. Because of contact, the compounding agent in the foam bleeds on the roller surface and contaminates the photoreceptor surface,
There is a problem that traces of contact of the transfer roller of the photoreceptor appear on the image.

On the other hand, in order to prevent the above-mentioned problem from occurring, a transfer roller further provided with a stain prevention layer formed of a resin material containing a conductivity-imparting agent on a conductive elastic layer has been proposed. Proposed. In such a transfer roller,
If the surface resin layer provided on the elastic layer is displaced, it causes transfer failure or transfer paper transfer failure. Therefore, the surface layer and the foamed elastic layer are bonded with an adhesive. However, in this case, the hardness of the transfer roller is increased, and the transfer force and transfer performance of the transfer paper are reduced. In addition, if the thickness of the adhesive is not uniformly controlled, the flatness of the roller surface is impaired, or the conductivity or There is a problem that the hardness varies, which also affects the image quality.

[0006]

SUMMARY OF THE INVENTION Accordingly, the present invention is directed to a problem with an elastic transfer roller provided with a resin layer on its surface, that is, it has low hardness and good flatness, and has no variation in surface conductivity and hardness. Another object of the present invention is to provide an improved method for manufacturing a toner image transfer roller that can simplify the manufacturing process.

[0007]

According to the method of manufacturing a toner image transfer roller of the present invention, a toner image transfer roller in which a conductive rubber elastic layer and a conductive resin layer are sequentially laminated on a core metal is manufactured. In the following, after applying a conductive chlorinated polyethylene resin tube to an elastic roll body having a conductive foamed ethylene propylene diene rubber elastic layer formed on the outer periphery of the core metal,
The roll body is heated to fuse the rubber and the resin.

In the method for producing a toner image transfer roller of the present invention, the foamed ethylene propylene diene rubber elastic layer may have an Asker C hardness of 20 to 40 degrees and an average bubble diameter of 250 μm or less. Preferably
More preferably, the material has a volume resistivity of 10 ⁵ to 10 ¹⁰ Ω · cm. The chlorinated polyethylene resin layer is preferably made of a material having a density of 10 ⁴ to 10 ¹² Ω · cm.
It is preferably carried out in the range of 170 ° C.

The toner image transfer roller obtained by the method of the present invention has an average bubble diameter of 250
A direct bonding composite layer of a conductive foamed ethylene propylene diene rubber elastic layer having a thickness of not more than μm and a conductive chlorinated polyethylene resin layer, which is provided with a surface having an Asker C hardness of 35 to 50 degrees. It is assumed that.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A toner image transfer roller manufactured according to the present invention has a structure as shown in FIG. That is, reference numeral 41 denotes a metal core formed of an aluminum material or an iron material. An adhesive is applied to the outside of the metal core, and a foam rubber tube made of ethylene propylene diene rubber (EPDM) is fitted to the metal core. By bonding, an elastic roll body having the foamed rubber elastic layer 42 formed thereon can be obtained. Alternatively, the foamable EPDM composition can be charged into a cylindrical mold to which the metal core 41 is attached, and foamed simultaneously with vulcanization to form the foamed rubber elastic layer 42. In this case, the elastic layer 42 is preferably formed by blending, for example, carbon black or the like as a conductivity-imparting material with EPDM, and foaming the same using a foaming agent such as an azo compound. And those having Asker C hardness in the range of 20 to 40 degrees are preferable. The volume resistivity of such a foamed rubber elastic layer is 10 ⁵ to
It is preferably within the range of 10 ¹⁰ Ω · cm.

[0011] The elastic roll body thus obtained is ground, if necessary, so as to have a desired diameter, and then is coated with a tube made of chlorinated polyethylene resin, and then is heated and fused to form a resin layer 43. To form The chlorinated polyethylene resin tube used here is preferably mixed with a conductivity-imparting material such as carbon black to form a tube.
^It is adjusted so as to have a volume resistivity of ⁴ to 10 ¹² Ω · cm, and does not need to have heat shrinkability, but is preferably heat shrinkable.

The chlorinated polyethylene resin tube thus adhered to the elastic roll body is fused to the foamed rubber elastic layer 42 by heating. It is desirable that the heating at that time be as uniform as possible. It is preferable to gradually raise the temperature using a heating furnace of the type. The temperature range of the heat treatment is preferably in the range of 100 to 170C. When the temperature is lower than 100 ° C., the adhesion is not sufficient, and when the temperature is higher than 170 ° C., it is not desirable because defects such as variation in surface smoothness and hardness of the elastic layer 2 appear.

[0013]

【Example】

(First Embodiment) A urethane-based adhesive was applied to the surface of a steel cored bar having a diameter of 8 mm and a length of 300 mm, and carbon black was added thereto to adjust the volume resistivity to 10 ⁵ to 10 ¹⁰ Ω · cm. Further, a foamed EPDM rubber tube having an average bubble diameter in the range of 150 to 250 μm and an Asker C hardness of 27 degrees is fitted and bonded to a cored bar, and the surface thereof is ground by a cylindrical grinder. An elastic roll body A having a diameter of 20 mm was prepared. For comparison, a carbon conductive foamable chloroprene rubber composition, a carbon conductive foamable silicone rubber composition, and a carbon conductive foamable foam having the same values of volume resistivity and hardness as described above. The silicone-ethylene propylene rubber composition and the ionic conductive foamable urethane rubber composition are placed in a mold having the same shape and dimensions as described above and a steel cored bar with an adhesive applied thereto. Then, foaming was performed, and the surface was further ground by a cylindrical grinder, thereby producing elastic rolls B to E having an outer diameter of 20 mm.

Next, a heat-shrinkable carbon conductive chlorinated polyethylene resin tube a having a diameter of 22 mm and a film thickness of 0.2 to 0.3 mm (Sumitube G, manufactured by Sumitomo Electric Industries, Ltd.)
9.5 mm, 0.1 mm thick, non-shrinkable carbon conductive urethane resin tube b (manufactured by Okura Industries), 19.5 m inside diameter
m, non-shrinkable carbon conductive PFA with a thickness of 0.05 mm
A resin tube c (manufactured by Gunze), an inner diameter of 19.5 mm, a film thickness of 0.05 mm, and a non-shrinkable ion-conductive PVDF resin tube d (manufactured by Okura Industries) were prepared. Then, these resin tubes are adhered to the elastic roll body without applying an adhesive, placed in an air-circulating heating furnace, and kept at 130 ° C. for 30 minutes to fuse the resin tubes. I let it.

In the resin layer of each transfer roller thus obtained, two cuts are made at intervals of 10 mm in parallel to the axis.
A 90 ° peel test was performed between the elastic layer and the resin layer, and the adhesion was evaluated according to the following criteria. The results are shown in Table 1. ：: The elastic layer is broken at the time of peeling, and adheres to the resin layer. Δ: The adhesive portion was broken at the time of peeling, and the elastic layer did not adhere to the resin layer. X: The elastic layer and the resin layer are easily in contact with each other but easily peeled off.

[0016]

[Table 1]

According to the results, the combination of the chlorinated polyethylene resin with the foamed EPDM rubber gives a particularly excellent heat-sealing state.
It can be seen that in all cases, the adhesion is insufficient.

(Second Embodiment) Average bubble diameter is 150 to 25
An elastic roll body F having an elastic layer with an Asker C hardness of 27 degrees was prepared using a conductive foamed EPDM rubber in the range of 0 μm. Then, after attaching a chlorinated polyethylene resin tube a to this, the Asker C hardness of the surface was measured. Further, transfer rollers were manufactured by a method in which the rollers were kept in an air circulation heating furnace at various heat treatment temperatures for 30 minutes. After removing the surface resin layer, Asker C
The hardness was measured, and the results are shown in Table 2.

Further, with respect to these transfer rollers, the maximum waviness (WCM, μm) of the roller surface was measured using a surface roughness meter (Surfcom 570A, manufactured by Tokyo Seimitsu Co., Ltd.), and the flatness was evaluated. Table 2 also shows the results of evaluating the adhesion by the same measurement method as in Example 1.

[0020]

[Table 2]

According to the results shown in Table 2, when the chlorinated polyethylene resin tube is fused to the elastic roll using the foamed EPDM rubber tube, the heat treatment temperature is set to 100 to 1.
It can be seen that when the temperature is in the range of 70 ° C., a transfer roller having good properties in all of Asker C hardness, flatness, and adhesion can be obtained.

(Third Embodiment) As a foamed EPDM rubber, a conductive foamed EPDM rubber tube having an average cell diameter in the range of 150 to 250 μm and similar to the above is used. Alternatively, elastic rolls G and H having an elastic layer at 40 degrees were prepared. Then, a chlorinated polyethylene resin tube a was applied to each of these elastic rolls, and then each transfer roller was manufactured at various heat treatment temperatures in the same manner as in Example 2. Table 3 shows the results obtained by measuring Asker C hardness for each of the transfer rollers thus obtained and examining the change in hardness.

[0023]

[Table 3]

Looking at the results in Table 3 together with the results in Table 2,
Foamed EPDM having Asker C hardness of 20 to 40 degrees
When a chlorinated polyethylene resin tube is fused to an elastic roll body using a system rubber tube at a heat treatment temperature of 100 to 170 ° C., Asker C hardness is 35 to 5
It can be seen that a transfer roller having a surface hardness in a preferable range of 0 degree can be obtained.

(Fourth Embodiment) Further, as the foamed EPDM rubber, the Asker C hardness is 30 degrees and the average cell diameter is different from 80 to 150 μm, 150 to 250 μm, or 250 to 350 μm, respectively. A chlorinated polyethylene resin tube a is applied to each of the elastic rolls I, J, and K in which an elastic layer is formed using a conductive foamed EPDM rubber tube, and the heat treatment temperature is variously changed. The treatment was performed for 30 minutes to fuse, and a transfer roller was manufactured. Table 4 shows the results of evaluating the flatness of the surface of these transfer rollers by the same measurement method as in Example 2.

[0026]

[Table 4]

Looking at the results in Table 4, the average bubble diameter is 150
An elastic roll body using a foamed EPDM rubber tube having a diameter of not more than 250 μm has a heat treatment temperature of 100 to 170 ° C.
It can be seen that when the chlorinated polyethylene resin tube is fused in the range of, a transfer roller having good flatness with little undulation on the roller surface can be obtained.

[0028]

According to the method of manufacturing the toner image transfer roller of the present invention, since the foamed EPDM rubber is used as the elastic layer and the chlorinated polyethylene resin layer is heat-sealed, the adhesiveness is reduced without using an adhesive. The transfer roller has good hardness, is suitable for forming a nip with the photoreceptor, and has good flatness. By a simplified manufacturing process, there is no variation in quality and high productivity. It can be manufactured and is economical.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a structure of a toner image transfer roller obtained by a manufacturing method of the present invention.

FIG. 2 is a conceptual diagram illustrating a structure of an electrophotographic apparatus incorporating a toner image transfer roller.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Photoconductor 2 Developing roller 3 Toner supply roller 4 Transfer roller 41 Metal core 42 Elastic layer 43 Resin layer 5 Charging roller 6 Cleaning roller 7 Exposure device 8 Transfer paper

Claims (5)

[Claims] In producing a toner image transfer roller in which a conductive rubber elastic layer and a conductive resin layer are sequentially laminated on the outer periphery of a core, a conductive foamed ethylene propylene diene rubber elastic is formed on the outer periphery of the core. Manufacturing a toner image transfer roller, comprising: applying a conductive chlorinated polyethylene resin tube to an elastic roll body having a layer formed thereon; and heating the roll body to fuse the rubber and the resin. Law. 2. The method according to claim 1, wherein the heating of the roll body is performed at 100 to 170.
The method for producing a toner image transfer roller according to claim 1, wherein the method is carried out within a temperature range of ° C. 3. The toner image transfer roller according to claim 1, wherein the foamed ethylene propylene diene rubber elastic layer has an Asker C hardness of 20 to 40 degrees and an average bubble diameter of 250 μm or less. Manufacturing method. 4. The foamed ethylene propylene diene rubber elastic layer is made of a material having a volume resistivity of 10 ⁵ to 10 ¹⁰ Ω · cm, and the chlorinated polyethylene resin layer is made of a material having a volume resistivity of 10 ⁴ to 10 ⁴ Ω · cm.
4. The method for producing a toner image transfer roller according to claim 1, wherein the roller is made of a material of 10 ¹² Ω · cm. 5. An average cell diameter of 250 μm around the core metal.
A direct bonding composite layer of the following conductive foamed ethylene propylene diene rubber elastic layer and a conductive chlorinated polyethylene resin layer, wherein the surface has an Asker C hardness of 35 to 50 degrees, which is characterized by being provided. Toner image transfer roller.