JP2007127163A - Manufacturing method for conductive roll - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a manufacturing method for a conductive roll capable of manufacturing the conductive roll having stable adhesion strength in a good working environment. <P>SOLUTION: The manufacturing method for the conductive roll is provided with a step for forming an inner layer 12 comprising a foam elastic body on a shaft 11; a step for covering a sleeve-like outer layer 13 comprising a rubber-like elastic body or a resin on an outer periphery of the inner layer; and a step for adhering the inner layer and the outer layer by an adhesion layer 14 formed on the whole in the circumferential direction of both axial ends between the inner layer and the outer layer by pouring an adhesive at an axial end between the inner layer and the outer layer by a dispenser 40 while rotating the shaft in a circumferential direction. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for producing a conductive roll used for imparting uniform charging to a photoreceptor or the like of an image forming apparatus such as an electrophotographic copying machine and printer, or a toner jet copying machine and printer.

  A roll used in contact with a photoconductor such as a conductive roll has a problem of causing scratches on the photoconductor. Since the image quality is liable to deteriorate when scratches are generated, a conductive roll has been proposed in which the occurrence of scratches is reduced by reducing the hardness of the roll. In such a conductive roll, the inner layer is made of a foam having a low hardness, and the outer layer provided on the outer periphery of the inner layer is made of a rubber-like elastic body having a relatively high hardness. It becomes an electroconductive roll which can suppress generation | occurrence | production (for example, refer patent document 1 and 2).

  Such two-layer type rolls usually need to be bonded to prevent tube misalignment. However, when bonding, it is better to bond the ends than the entire surface. Is preferable because it is small and can be brought into uniform contact with the photoreceptor.

  As an end bonding means at both ends, for example, there is a method of heat-bonding after performing a solvent-based urethane adhesive by spray coating, but the solvent-based adhesive only deteriorates the working environment due to scattering of the solvent, etc. In addition, there is a problem that the adhesive layer becomes thin and the adhesive strength is lowered.

JP 2003-156923 A JP 2004-354503 A

  This invention makes it a subject to provide the manufacturing method of the electroconductive roll which can manufacture the electroconductive roll with which adhesive strength was stabilized in a favorable working environment in view of such a situation.

  The first aspect of the present invention that solves the above-described problems includes a step of forming an inner layer made of a foamed elastic body on a shaft, and a step of coating a sleeve-like outer layer made of a rubber-like elastic body or resin on the outer periphery of the inner layer. And by injecting an adhesive into the axial end between the inner layer and the outer layer by a dispenser while rotating the shaft in the circumferential direction, the axial end portions of the inner layer and the outer layer are The method includes the step of bonding the inner layer and the outer layer with an adhesive layer formed over the entire circumferential direction.

  According to a second aspect of the present invention, in the method for producing a conductive roll according to the first aspect, the adhesive has a viscosity of 10 to 300 (Pa · s) and a solid content of 50% or more. It exists in the manufacturing method of the electroconductive roll made into.

  A third aspect of the present invention is the method for producing a conductive roll according to the first or second aspect, wherein the adhesive does not contain a solvent.

  A fourth aspect of the present invention is the process for producing a conductive roll according to any one of the first to third aspects, wherein the adhesive contains a urethane-based or silicone-based polymer. Is in the way.

  A fifth aspect of the present invention is the conductive roll manufacturing method according to any one of the first to fourth aspects, wherein the adhesive layer has an axial length of 1 to 10 mm. It is in the manufacturing method.

  According to a sixth aspect of the present invention, in the method for producing a conductive roll according to any one of the first to fifth aspects, taper portions are formed on outer peripheral portions of both end portions in the axial direction of the inner layer. In the manufacturing method of the adhesive roll.

  According to the present invention, a conductive roll manufacturing method capable of manufacturing a conductive roll with stable adhesive strength in a favorable working environment is provided.

  The method for producing a conductive roll according to the present invention includes a step of forming an inner layer made of a foamed elastic body on a shaft, a step of coating a sleeve-like outer layer made of a rubber-like elastic body or resin on the outer periphery of the inner layer, While rotating the shaft, an adhesive is injected into the axial end portion between the inner layer and the outer layer by a dispenser, so that the inner layer and the inner layer are formed in the entire circumferential direction of both axial end portions. Adhering to the outer layer. By including the steps described above, a conductive roll having a stable adhesive strength can be produced in a favorable working environment.

  Hereinafter, the manufacturing method of the electroconductive roll of this invention is demonstrated using figures. FIG. 1 shows a cross-sectional view of a conductive roll according to the present invention. As shown in FIG. 1A, a conductive roll 10 according to the present invention has an inner layer 12 made of a foamed elastic body on a shaft 11, and rubber-like elasticity is provided on the outer periphery of the inner layer 12 via an adhesive layer 14. It has the outer layer 13 which consists of a body or resin. In addition, the conductive roll 10 concerning this invention may provide the surface treatment layer 13a on the surface of the outer layer 13, as shown in FIG.1 (b).

  The manufacturing method of the electroconductive roll shown in FIG.1 (b) is demonstrated using FIGS.

  The inner layer forming method will be described with reference to FIGS. First, the inner layer 12a before foaming is extruded onto the core metal 11 using the crosshead die 20 shown in the cross-sectional view of FIG. As shown in FIG. 2, the cored bar 11 is positioned and held by the cored bar guide 21 in the crosshead die 20 for molding the inner layer 12 a before foaming. The core metal 11 is advanced from such an injection hole (not shown) into the crosshead die 20 while injecting unfoamed unvulcanized rubber to be the inner layer 12a before foaming, and the inner layer 12a before foaming is extruded onto the core metal 11 Mold. Thereafter, the cored bar 11 and the inner layer 12a before foaming are cut to a desired length. In addition, you may form the inner layer 12a before foaming by injection molding etc. using a metal mold | die.

  Here, FIG. 3 shows a cross-sectional view of an example of a mold for producing the conductive roll according to the present invention. The metal mold 30 includes a cylindrical mold 31 made of a metal pipe member whose inner diameter is defined with high accuracy, and a top 32 that holds both ends of the core metal 11. The cylindrical mold 31 and the top 32 are concentric. It is held by a presser mold 33 that is a split mold provided at both ends so as to be in a state. Here, a recess 32b is provided around the fitting hole 32a of the core bar 11 of the top 32, and a gas vent hole 32c is provided so as to communicate with the recess 32b. Further, both end portions of the cylindrical mold 31 and the top 32 are simply brought into contact with each other, and the concave portion 32 b communicates with a gap 34 between the both ends of the cylindrical mold 31 and the top 32. Yes. Therefore, after molding, a space portion remains in the concave portion 32b between the inner layer 12 and the top 32, and the space portion communicates with the gas vent hole 32c and the gap 34.

  Using such a mold 30, first, both end portions of the core metal 11 are inserted into the fitting holes 32 a of the top 32, and the top 32 and the cylindrical mold 31 are held by the presser mold 33. Thereafter, by heating the mold 30, the inner layer 12a before foaming is foamed and vulcanized to form the inner layer 12 as shown in FIG. 3B.

  A method for forming the outer layer will be described with reference to FIG. First, as shown in FIG. 4A, an outer layer manufacturing die 6 and an outer layer manufacturing die 7 are installed. At this time, it is installed so that the axial center of the outer layer manufacturing mold 6 and the axial center of the outer layer manufacturing mold 7 coincide. By installing in this way, the cylindrical space 8 is formed. The outer layer manufacturing die 6 and the outer layer manufacturing die 7 may be any metal having a certain degree of hardness. The outer diameter of the outer layer manufacturing mold 6 may be substantially the same as the inner diameter of the desired outer layer, and the outer diameter of the outer layer manufacturing mold 7 may be approximately the same as the outer diameter of the desired outer layer.

  Next, as shown in FIG. 4B, the outer space manufacturing die 6 and the outer layer manufacturing die 7 are preheated, and a cylindrical space 8 formed between the outer layer manufacturing die 6 and the outer layer manufacturing die 7. Then, the raw material of the outer layer 13 is injected and heated. When the outer layer 13 is hardened, the outer layer 13 is removed from the outer layer manufacturing die 7 to obtain a sleeve-shaped outer layer 13 as shown in FIG.

  Next, the sleeve-shaped outer layer 13 is coated on a core metal having the same diameter as the outer layer 13 and immersed in a surface treatment liquid, or a surface treatment liquid is applied by spraying, etc. By applying the treatment liquid and then heating, the surface treatment layer 13a is formed on the surface of the outer layer 13 as shown in FIG. Thereby, the desired outer layer 13 and the surface treatment layer 13a are obtained.

  In addition, the formation method of the inner layer 12 and the outer layer 13 is not limited to the method mentioned above. Further, the inner layer 12 may be formed after the outer layer 13.

  A method of bonding the inner layer 12 and the outer layer 13 will be described with reference to FIG. First, as shown in FIG. 5A, the inner layer 12 is covered with the outer layer 13.

  Next, as shown in FIG. 5 (b), the dispenser 40 is inserted into the axial end between the inner layer 12 and the outer layer 13, and the adhesive which is the raw material of the adhesive layer is injected while rotating the shaft 11 in the circumferential direction. Thus, the adhesive is applied over the entire circumferential direction of both end portions of the inner layer 12 and the outer layer 13. At this time, by inserting the dispenser 40, the inner layer 12 and the outer layer 13 are crushed in the axial direction, but after the dispenser 40 is pulled out, the adhesive is stretched by surface tension. The dispenser 40 preferably has a needle diameter of 1 to 2 mm. In FIG. 5, when the inner layer 12 and the outer layer 13 are bonded, the inner layer 12 and the outer layer 13 are bonded vertically, but of course, they may be bonded horizontally. Furthermore, although both ends in the axial direction may be bonded together, they may be performed separately.

  By curing this at room temperature or by heating, the adhesive layer 14 is applied over the circumferential direction of both ends of the inner layer 12 and the outer layer 13 as shown in FIG.

  The adhesive according to the present invention preferably has a viscosity of 10 to 300 (Pa · s) and a solid component of 50% or more. If the viscosity of the adhesive is lower than the above-mentioned range, the adhesive flows downward due to low viscosity when injected upward, and if it is higher than the above-mentioned range, it is injected because the viscosity is too high. This is because it becomes difficult. The reason why the solid component of the adhesive is set to 50% or more is that when the solid component is less than 50%, drying of the non-adhesive layer is delayed, and “floating” occurs between the inner layer and the outer layer. By using the adhesive in this range, it is possible to inject the adhesive into the axial end portion between the inner layer and the outer layer. Moreover, it is preferable that the adhesive concerning this invention does not contain a solvent. This is because the adhesive according to the present invention is an adhesive that is injected by a dispenser. Furthermore, the adhesive according to the present invention preferably contains a urethane-based or silicone-based polymer. An example of such an adhesive is an acrylic-modified silicone resin. By using such a rubber-based adhesive, the addition to the porous lower layer becomes strong, and the application surface of the adhesive can be reduced. An adhesive layer is formed by curing such an adhesive at room temperature or heat, and a conductive roll having high adhesive strength is obtained. Moreover, the adhesion method between the inner layer and the outer layer using the adhesive according to the present invention does not deteriorate the working environment like the adhesion method in which heat bonding is performed after spray coating.

  The adhesive layer concerning this invention can be formed so that the length of an axial direction may be set to 1-10 mm by using the above adhesives. Conventionally, the adhesive layer provided by spray coating or the like requires an axial length of 20 to 50 mm in order to bond the inner layer and the outer layer, whereas the adhesive layer of the present invention has an axial length of Since 1-10 mm is sufficient, a small amount of adhesive is sufficient.

  Here, in the present invention, as described above, the dispenser 40 is inserted into the gap between the both ends of the inner layer 12 and the outer layer 13 to inject the adhesive, but tapered portions are provided at the outer peripheral portions of the both axial ends of the inner layer 12. Thus, the injection of the adhesive by the dispenser 40 can be facilitated. FIG. 6 shows how the adhesive is injected when the inner layer 12 is provided with a tapered portion. The inner layer 22 has tapered portions 22 a at outer peripheral portions at both ends in the axial direction, and the adhesive 40 can be injected in a state where the dispenser 40 is disposed between the tapered portion 22 a and the outer layer 13. In this case, an adhesive layer is formed in the gap between the tapered portion 22a and the outer layer 13, and the inner layer 22 and the outer layer 13 are firmly bonded. Of course, in this case, the dispenser 40 may be inserted from the gap between the tapered portion 22a and the outer layer 13 further into the inside, and the adhesive may be injected in the same manner as described above.

  The inner layer according to the present invention is made of a foamed elastic body, and examples thereof include open cell polyurethane foam having a hardness of 500 N or less. The hardness of 500 N or less means that the hardness according to the measuring method of JIS K6400 is 500 N or less, for example, low hardness that cannot be measured by Asker C. The hardness of the foamed elastic body is not limited to this.

The material is not particularly limited as long as it is, for example, open-cell polyurethane, but it is necessary to impart conductivity with a conductive agent. The conductivity may be imparted by electronic conduction using conductive carbon, ion conduction using lithium perchlorate or the like, or hybrid conduction combining these. The surface resistance value of the inner layer is preferably about 5 × 10 ⁴ Ω or less.

On the other hand, the outer layer is made of a conductive rubber-like elastic body or resin. Those having electrical conductivity or imparting electrical conductivity are preferred, the volume resistivity is 1 × 10 ¹⁰ Ω or less, and the rubber hardness is preferably 90 ° or less, more preferably 60 ° or less in JIS A. is there.

  Examples of the material for the outer layer include epichlorohydrin rubber, silicone rubber, EPDM, NBR, CR, and the like. Moreover, when providing electroconductivity, the electronic conduction by conductive carbon, the ionic conduction by lithium perchlorate, etc., or the hybrid conduction which combined these may be sufficient.

  The outer layer may be provided with a surface treatment layer on the surface in advance or after coating the inner layer. Here, the surface treatment layer is formed by impregnating a surface treatment liquid containing isocyanate. The surface treatment layer formed so as to be impregnated with the surface treatment liquid is integrally formed so as to gradually become sparse from the surface toward the inside. By forming such a surface treatment layer on the surface of the elastic layer, migration of contaminants such as a plasticizer to the surface of the conductive roll can be prevented, and the conductive roll prevents the photoreceptor from being contaminated.

  As the surface treatment liquid, an isocyanate compound dissolved in an organic solvent, or a carbon black added thereto can be used. At least selected from an acrylic fluorine-based polymer and an acrylic silicone-based polymer. It is preferable to use a surface treatment liquid containing at least one of one polymer and a conductivity imparting agent together with an isocyanate component.

  Here, as the isocyanate compound, 2,6-tolylene diisocyanate (TDI), 4,4′-diphenylmethane diisocyanate (MDI), paraphenylene diisocyanate (PPDI), 1,5-naphthalene diisocyanate (NDI) and 3,3 -Dimethyldiphenyl-4,4'-diisocyanate (TODI) and the above-mentioned multimers and modified products.

  The acrylic fluorine-based polymer and the acrylic silicone-based polymer are soluble in a predetermined solvent and can be chemically bonded by reacting with an isocyanate compound. The acrylic fluorine-based polymer is, for example, a solvent-soluble fluorine-based pomer having a hydroxyl group, an alkyl group, or a carboxyl group, and examples thereof include block copolymers of acrylic acid esters and fluorinated alkyl acrylates and derivatives thereof. . The acrylic silicone polymer is a solvent-soluble silicone polymer, and examples thereof include block copolymers of acrylic acid esters and acrylic acid siloxane esters, and derivatives thereof. These polymers can be used alone or in combination. The polymer in the surface treatment liquid is preferably 2 to 30% by weight based on the isocyanate component. If the amount is too small, the effect of retaining the carbon black in the surface treatment layer becomes small. If the amount is too large, the isocyanate component becomes relatively small and an effective surface treatment layer cannot be formed.

  Moreover, it is preferable to use carbon black as a conductivity imparting agent in the surface treatment liquid. The type of carbon black is not particularly limited and is the same as described above. The carbon black in the surface treatment liquid is preferably 10 to 40% by weight with respect to the isocyanate component. If it is less than this, effective charging characteristics cannot be exhibited, and if it is too much, problems such as dropping off are caused, which is not preferable.

  Furthermore, the surface treatment liquid contains a solvent that dissolves these acrylic fluorine-based polymer or acrylic silicone-based polymer and an isocyanate compound. Although it does not specifically limit as a solvent, What is necessary is just to use organic solvents, such as ethyl acetate, methyl ethyl ketone (MEK), and toluene.

  The method of impregnating the outer layer with the surface treatment liquid may be a method of immersing in the surface treatment liquid or a method of applying the surface treatment liquid by spraying or the like. What is necessary is just to adjust suitably the time to immerse in surface treatment liquid, the frequency | count of spraying, or the quantity of surface treatment liquid. The surface treatment layer is preferably formed by impregnating the outer layer with a surface treatment solution and then curing. If the surface treatment layer is formed on the outer layer, normal temperature solid components such as fluorine and silicone are likely to be crystallized and appear on the surface of the conductive roll when dried by heating. The adhesion preventing performance such as the above is greatly improved, and it is possible to obtain a conductive roll which is difficult to adhere dirt. Furthermore, the crystallization of the solid component at room temperature improves the bleed prevention effect of blocking contaminants that bleed from the inside of the conductive roll to the surface.

Hereinafter, the present invention will be described based on examples.
Example 1
<Method for manufacturing outer layer>
To 100 parts by weight of epichlorohydrin rubber (Epichromer CG-102; manufactured by Daiso), 0.5 parts by weight of sodium trifluoroacetate, 3 parts by weight of zinc oxide, 2 parts by weight of stearic acid, and 1.5 parts by weight of vulcanizing agent are added. Then, they were kneaded by a roll mixer, press molded, and the outer surface was polished to form a rubber sleeve having a thickness of 0.5 mm and an inner diameter of 9.0 mm. A surface treatment liquid in which 100 parts by weight of ethyl acetate and 10 parts by weight of an isocyanate compound (MDI; manufactured by Dainippon Ink Co., Ltd.) were mixed on the rubber sleeve surface was sprayed twice at 23 ° C. by spraying, and then the surface treatment liquid was impregnated. A surface treatment layer was formed by heating and drying at 120 ° C. to obtain an outer layer.
<Inner layer manufacturing method>
100 parts by weight of medium to high nitrile rubber with 33% nitrile (Mooney viscosity: ML _{1 + 4} (100 ° C.) 30), 5 parts by weight of zinc white, 1 part by weight of stearic acid, 25 parts by weight of Toka Black # 5500, -30 parts by weight of (2-ethylhexyl) phthalate (DOP), 1 part by weight of sulfur, 3.5 parts by weight of vulcanization aid, 5 parts by weight of foaming agent ADCA, and 3 parts by weight of foaming aid were added and mixed with a roll mixer. The mixture was kneaded, molded to 1 mm on the surface of a shaft having a diameter of 6 mm, and foamed in a mold to a thickness of 1.5 mm to obtain an inner layer.
<Adhesion method between inner layer and outer layer>
After coating the inner layer with the outer layer, a normal temperature curing type silicone adhesive was injected into both ends with a dispenser and cured at room temperature to bond the inner layer and the outer layer to obtain a conductive roll.

(Comparative Example 1)
In the bonding method between the inner layer and the outer layer, a conductive urethane adhesive (20% solid content) was sprayed on both ends 10 mm of the inner layer and the outer layer and then heated and cured at 120 ° C. for 30 minutes. Got a roll.

(Test Example 1): Peel test Table 1 shows the results of a 90 ° peel test in which one end of the inner layer in the longitudinal direction is fixed and one end of the outer layer is pulled in a direction perpendicular to measure the peel strength (kgf / 10 mm). Show.

(Test example 2): Continuous printing test The charging rolls of the above examples and comparative examples are attached to the charging portion of a commercially available laser printer (SPEDIA N5 manufactured by CASIO), and in a high temperature and high humidity environment (H / H: 30). The conductive roll was observed after continuous printing of 10,000 sheets at ° C x 85% RH). The results are shown in Table 1.

(Summary of results)
As shown in Table 1, the conductive roll of Example 1 did not peel until a force of 5.0 kg or more was applied, whereas the conductive roll of Comparative Example 1 applied a force of around 1.0 kg. It peeled off. Further, in the actual machine evaluation test, the conductive roll of Example 1 did not generate a deviation between the inner layer and the outer layer even after continuous printing of 10,000 sheets, but the conductive roll of Comparative Example 1 continuously printed 1200 sheets. At that time, one end of the conductive roll peeled off.

  From this, it turned out that the manufacturing method of the electroconductive roll of this invention can manufacture the electroconductive roll with which the adhesive strength with an inner layer and an outer layer was stabilized.

It is sectional drawing which shows the electroconductive roll concerning this invention. It is sectional drawing which shows the manufacturing method of the electroconductive roll of this invention. It is sectional drawing which shows the manufacturing method of the electroconductive roll of this invention. It is a perspective view which shows the manufacturing method of the electroconductive roll of this invention. It is sectional drawing which shows the manufacturing method of the electroconductive roll of this invention. It is sectional drawing which shows the mode of adhesive injection | pouring at the time of providing a taper part in an inner layer.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Conductive roll 11 Shaft 12 Inner layer 13 Outer layer 13a Surface treatment layer 14 Adhesive layer 22 Inner layer 22a Taper part 40 Dispenser

Claims (6)

A step of forming an inner layer made of a foamed elastic body on the shaft, a step of covering the outer periphery of the inner layer with a sleeve-like outer layer made of a rubber-like elastic body or resin, and a dispenser while rotating the shaft in the circumferential direction. The inner layer is an adhesive layer formed over the entire circumferential direction of both axial end portions between the inner layer and the outer layer by injecting an adhesive into the axial end portion between the inner layer and the outer layer. And a step of adhering the outer layer to the outer layer. 2. The method for producing a conductive roll according to claim 1, wherein the adhesive has a viscosity of 10 to 300 (Pa · s) and a solid content of 50% or more. . The manufacturing method of the conductive roll of Claim 1 or 2 WHEREIN: The said adhesive agent does not contain a solvent, The manufacturing method of the conductive roll characterized by the above-mentioned. The manufacturing method of the conductive roll in any one of Claims 1-3 WHEREIN: The said adhesive agent contains a urethane type or a silicone type polymer, The manufacturing method of the conductive roll characterized by the above-mentioned. The manufacturing method of the conductive roll in any one of Claims 1-4 WHEREIN: The length of the axial direction of the said contact bonding layer is 1-10 mm, The manufacturing method of the conductive roll characterized by the above-mentioned. The method for manufacturing a conductive roll according to any one of claims 1 to 5, wherein tapered portions are formed at outer peripheral portions of both end portions in the axial direction of the inner layer.

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