JP2003131453A - Conductive roller and production thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a conductive roller that has almost no undulation (recesses and projections) on the surface of a coating film and is free of bulges of the coating film on both ends of a roller main body. SOLUTION: A coating tank 5 is disposed at an angle to the direction in which a roller formation body is moved. With the roller formation body held horizontally, the roller main body, except a length of 5 to 10 mm left from the leading end of the roller main body, is brought into contact with the surface of a coating liquid stored in while overflowing from the coating tank 5. The roller main body is moved while rotating. Thereby the roller main body, except a length of 5 to 10 mm left from the rear end, is coated. Subsequently, both the ends that are not coated with the coating liquid are coated with a solvent that is the same kind as the solvent of the coating liquid. Then, the surface of the roller formation body is dried.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive roller used as a developing roller, a charging roller, a transfer roller or the like in an OA equipment such as an electrophotographic apparatus, and a manufacturing method thereof.

[0002]

2. Description of the Related Art A conductive roller of this type has a roller body formed of an elastic body on the outer periphery of a shaft body, and the roller molded body (which is a conductive roller before coating with a coating liquid) is used as a shaft. It is manufactured by vertically dipping the body vertically in a coating solution in a coating tank for coating, and then drying the coating solution. However, in this vertical dipping method, when the roller is pulled up, the coating liquid drips downward to cause coating unevenness, or even the shaft end is coated, so after drying, finishing steps such as peeling and cutting are performed. There was a problem that needed.

In addition, when coating the roller body, a method of manufacturing by applying the roller while rotating the roller horizontally is practiced. In this method, the entire length of the roller body is added to the coating liquid. When the roller is moved in contact with the roller while rotating and is pulled up from the coating liquid, there is a problem that the liquid traces are formed in a straight line over almost the entire length of the roller main body and the coating becomes uneven.

Therefore, the applicant of the present invention arranges the coating tank in a parallelogram in plan view with both side walls inclined in parallel to the moving direction of the roller shaping body, and arranges it from one end (starting end) of the roller main body to another. A method is proposed in which the coating liquid is applied in a spiral shape with a constant width over the end. By defining the inclination angle, the number of rotations of the roller, and the moving speed, the traces of liquid breakage became inconspicuous and this point was improved, but as shown in FIG.
Depending on the type of coating liquid, there is a problem that a bulge 24a of the coating film 24, which is thicker than other portions, is likely to be formed at a position 5 to 15 mm from the center of both end portions 23 on the surface of the roller body 22. It was happening.

The cause of this is that the coating liquid A is pulled from the end portions 23 on both sides of the roller body 22 toward the central portion by surface tension, and the drying speed of the coating liquid A is different between the both ends and the central portion. It is presumed that the concentration of the coating liquid A on both end portions 23 becomes high and the coating liquid A is likely to accumulate on both end portions 23. As a result, the end portions 23 on both sides of the surface of the roller body 22 are
A bulge 24a of the coating film 24 having a thickness of 20 to 50 micrometers (μm) is formed over (a range of 5 mm to 15 mm from the end of the roller body).

[0006]

If there is a bulge of the coating film on both ends of the roller body, for example, when a conductive roller is attached to the photosensitive drum, the photosensitive drum and the conductive roller will be separated from each other. There is a problem that a gap is created between the two and the image becomes unclear.

Conventionally, this problem has been dealt with by making the length of the roller body slightly longer than the product size and cutting off both end portions where the bulge of the coating film has occurred. However, this method is disadvantageous in that the material is wasted and uneconomical, and the extra work for cutting off both end portions is increased to lower the production efficiency.

The present invention has been made in view of the above points, and in the step of applying the coating liquid, almost no linear or spiral liquid traces of the coating film are produced, and further, both ends are formed. It is an object of the present invention to efficiently provide a conductive roller without bulging of a coating film.

[0009]

In order to solve the above-mentioned problems, in the method of manufacturing a conductive roller of the present invention, the roller molded body is arranged horizontally while being inclined with respect to the moving direction. The coating liquid surface that overflows into the coating tank is brought into contact with the roller body at a position 5 to 10 mm away from the starting end of the roller body, and is moved while rotating to move from the end to 5
The coating is performed leaving the length of 10 mm, and then the same type of solvent as the solvent of the coating solution is applied to both ends where the coating solution is not applied, and the surface of the roller body is dried. Characterize.

By using the coating tank which is arranged so as to be inclined with respect to the moving direction of the roller molded body, the roller body can be sequentially coated from one end (starting end) to the other end (terminating end), and is rotated. By moving and coating while moving, it is possible to coat without leaving a linear liquid cut mark. By keeping the roller body horizontal and moving it closer to the coating tank, the coating is performed in contact with the overflowing coating liquid surface without contacting the coating tank. By coating with the end of the roller main body remaining 5 to 10 mm at the starting end and the terminating end, a range where the solvent is continuously applied is secured.

While the coating liquid is being applied and then the coating liquid is not dried, a solvent of the same type as the solvent of the coating liquid is applied to both ends of the roller body not coated with the coating liquid. By doing so, the movement of the coating liquid to the solvent side is measured, and the swelling of the end portion of the coating liquid is eliminated. After coating the solvent, the coating liquid and the solvent are dried to complete the conductive roller.

In this method of manufacturing a conductive roller, it is not necessary to form the roller body longer than the finished length and to cut it after coating, assuming that a bulge is generated as in the prior art, and waste of material and cutting man-hours is not required. Production efficiency improves.

According to a second aspect of the present invention, there is provided a method of manufacturing a conductive roller in which the side of the coating tank is a parallelogram in plan view, and the inclined side which is a side that intersects the roller moving direction at an angle is inclined. The distance between the parallel sides, which intersects the axial direction of the roller at an angle of 30 ° or more and are parallel to the moving direction of the roller, corresponds to the width of the roller body for applying the coating liquid. It is characterized by intervals.

The side of the coating tank is a parallelogram in plan view, and the inclined side intersecting the roller moving direction is inclined by 30 ° or more with respect to the roller moving direction, whereby the roller body is coated with the coating liquid. It is possible to reduce the pitch of spiral liquid traces (also called irregularities or undulations) that occur when the surface is separated from the surface, and to suppress the height of spiral irregularities on the surface to a predetermined height (for example, 5 μm or less). Can be stabilized. By setting the interval of the parallel side parallel to the roller moving direction to be the interval corresponding to the width of the roller body for applying the coating liquid, both end portions of the roller body passing along the surface of the coating liquid are set to a predetermined distance. The width (5 to 10 mm) is applied.

According to a third aspect of the present invention, there is provided a method of manufacturing a conductive roller, wherein a solvent is applied to both ends of the roller body not coated with the coating liquid by spraying the solvent while rotating the roller body. It is characterized by applying. The spray device is small and simple in structure, can be mounted close to the coating tank, and can apply the solvent before the coating liquid dries. This makes it possible to prevent the solvent and the coating liquid from easily mixing with each other and prevent the end portion of the coating film from swelling.

In the electroconductive roller according to claim 4, the solvent applied to both ends of the roller body not coated with the coating liquid is methyl ethyl ketone (also referred to as MEK) or dimethylformaldehyde (also referred to as DMF) or a mixture thereof. Is characterized in that. The material of the roller body is, for example, NBR, EPDM, urethane rubber, silicone rubber,
The coating liquid is epichlorohydrin rubber, CR or the like, and the coating liquid is a solvent that uses urethane resin, acrylic resin, fluorine resin, etc. as a solute, and uses MEK, DMF, etc. as a solvent, and is a solvent that is applied to the end of the roller body. As a solute of the coating liquid easily moves, a solvent of the same kind, that is, ME
K and DMF are preferably used.

A conductive roller according to a fifth aspect is a conductive roller such as a developing roller, a charging roller and a transfer roller used in an electrophotographic apparatus or the like, and the outer circumference of the shaft body having a part of both ends left. A roller in which a cylindrical roller body made of a conductive elastic body and a coating liquid film are concentrically formed on the core, and the coating liquid in the central portion is induced by a solvent at an axial end portion of the coating liquid film to dry the roller. The outer peripheral difference between the axial center and both ends is less than 10 μm.

A coating liquid is applied from each end of the roller main body made of an elastic body, leaving a range of 5 to 10 mm in the direction of the central portion, to form a coating liquid film (referring to a coating film before drying). The coating liquid is formed and the solvent is applied to the area where the coating liquid film is not formed, and the coating liquid that agglomerates at the end of the coating liquid film is further moved to the solvent portion to obtain the thickness of the coating film after drying. Becomes thinner in sequence from the end of the coating film toward the end of the roller body, and does not bulge. In this way, the difference in outer circumference between the central portion and both end portions in the axial direction of the roller is set to 10 μm or less. As a result, even when used as a developing roller or the like, a gap is not generated at the roller end portion and the image is not blurred.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of a conductive roller and a manufacturing method thereof according to the present invention will be described below with reference to the drawings. FIG. 1A is a sectional view of the entire conductive roller 1 as an embodiment of the present invention, and the coating film 4 is shown thick for emphasis. FIG. 1B is a partial cross-sectional view showing one end portion in an enlarged manner.

As shown in FIG. 1 (a), a conductive roller 1 of the present embodiment comprises a cylindrical roller body 2 made of an elastic material such as rubber, and a shaft body 3 penetrating the center of the roller body 2. , And a coating film 4 coated on the surface of the roller body 2. As shown in FIG. 1 (b), the shaft body 3 is composed of a round rod-shaped shaft body 3a having a roller body concentrically formed on the outer periphery thereof, and a shaft end portion 3b having a small diameter and a short diameter projecting from both ends thereof. A part of the shaft body 3a and the shaft end 3b project outward from both ends of the roller body 2.

Although the specific dimensions of the conductive roller 1 are not limited, the roller body 2 has a total length of 200 mm to 40 mm.
It is 0 mm (250 mm in this example), and the diameter d is about 6 mm to 16 mm (6.9 in this example, as shown in FIG. 1B).
mm), and the thickness t of the roller body 2 is 1.
It is 0 to 5.0 mm (1.0 mm in this example), and the thickness p of the applied coating film 4 is around 0.05 mm in the radial direction. The thickness of the coating film 4 is the end portion (coating film end portion 4a).
The bulge does not occur, and the tip 4b forms only a minimum radius R. As a result, even when it comes into contact with the photosensitive drum, it is evenly contacted up to the vicinity of the tip.

FIG. 2A shows a plan view of the coating tank 5, wherein the coating tank main body 6 is a parallelogram when viewed from above, and the side parallel to the moving direction of the conductive roller 1 (arrow x). It has parallel side 6a, which is a side, and inclined side 6b that intersects the moving direction of conductive roller 1 at an angle, and inclined side 6b is α ° with respect to the axial direction y of conductive roller 1. It is inclined. A side groove 7 is formed around the coating tank body 6, and the coating liquid overflowing the coating tank body 6 is collected in the side groove 7 and a collecting pipe 8 is provided.
The coating liquid is collected into the coating tank main body 6 again from the liquid supply pipe 9 through a flow means (not shown) (including viscosity adjustment). As the coating liquid, solutes such as urethane resin and acrylic fluorine resin are used according to the purpose, and these are adjusted to a predetermined viscosity with a solvent such as MEK or DMF that dissolves easily and is easily dried. .

As shown in the front view (partially sectional view) of the coating tank 5 in FIG. 2 (b), the conductive roller 1 has its outer peripheral surface brought close to the upper end of the side of the coating layer 5 so as to be horizontal. Supported, coating tank 5
Is in contact with the surface of the coating liquid (not shown) that overflows. Both ends 12 of the roller body 2 are projected outward from the parallel side 6a of the coating tank 5, and the coating liquid is not applied to this portion. Both end portions 12 are portions to be coated with a solvent later, and are preferably 5 to 10 mm. If the uncoated range is less than 5 mm from the end of the roller body, the conventional solvent cannot be coated with the required amount of solvent to eliminate the bulge of the coated film. If this range exceeds 10 mm, the coating film The range in which the thickness becomes thin becomes large, which may affect image formation.

A procedure for applying the coating liquid to the roller body 2 using the coating tank 5 will be described with reference to FIG. Figure 3
3A shows the start time of coating, FIG. 3C shows the end time, and FIG. 3B shows a plan view during coating. As shown in FIG. 3A, the roller body 2 has its axis y intersecting the inclined side 6b of the parallelogram coating tank 5 at an inclination angle α. As for the positional relationship between the roller main body 2 and the parallel side 6a of the coating tank 5, the length L of the roller main body 2 is larger than the width w of the coating tank 5 as shown in FIG. Both ends 12
Is projected from the coating tank 5 as a portion not coated with the coating liquid. The coating conditions in the coating tank 5 are, for example, roller moving speed = 3.9 mm / sec and rotation speed = 37 rp.
m, the coating liquid has a viscosity of 300 to 400 mPa · sec and a solid content of 12 to 15% by weight. By setting the inclination angle α between the axis y of the roller body 2 and the inclined side 6b to be 30 ° or more, the waviness (unevenness) of the coating film on the surface of the roller body 2 is 5 μm or less.

With reference to FIG. 4, the process of applying the solvent 11 to the portion not coated with the coating liquid (also referred to as both ends 12 and 12 of the roller body) will be described. First, FIG. 4 (a)
As shown in FIG. 2, after the coating liquid is applied to the roller body 2 by the coating tank, the roller film 2 is adjacent to the end 4a of the coating film 4 which is slightly swollen (the thickness of the coating film 4 is exaggerated for clarity). A solvent 11 is applied by a spray 10 to the end 12 which is not coated with a matching coating solution. The timing for applying the solvent 11 is
Immediately after the roller body 2 is separated from the coating liquid surface (preferably within 10 seconds), the roller body 2 is applied while being rotated. FIG. 4B shows a state in which the solvent 11 is applied to the end 12 and rises, and FIG. 3C shows that the coating film 4 is being formed toward the solvent 11 at the end 12 (arrow m). The state in which the coating liquid moves and the bulge 4a at the end of the coating film 4 decreases is shown. Coating film 4 with the passage of time
The coating liquid that is forming the film moves, dries, and then, as shown in FIG.
As shown in FIG. 5, the coating film 4 is formed on the end portion 12 so as to become thinner toward the end portion, and the bulge 4a is eliminated.

FIG. 6 shows the result of measuring the thickness of the coating film, and FIG. 6 (a) shows the thickness of the coating film of the conductive roller manufactured by the manufacturing method of the present invention. The thickness of the coating film of the conductive roller manufactured by the conventional manufacturing method is shown in b). The measurement method is a non-contact type outer diameter measuring machine, in which the laser oscillation part is moved at a constant speed parallel to the axis of the conductive roller, and the distance from the upper edge position of the laser oscillation part to the roller surface is measured. Then, it was measured in the longitudinal direction at a pitch of 0.5 mm. As the measuring machine, a laser outer diameter measuring machine LS-5000 manufactured by Keyence Corporation was used.

As shown in FIG. 6 (a), the thickness difference d of the coating film at the end portion of the conductive roller by the manufacturing method of the present invention is about 5 μm, and the coating by the conventional manufacturing method shown in FIG. 6 (b) is performed. The film thickness difference d'is about 50 μm, which is greatly reduced. The numerical values for thickness and position in the table are indicated by indices.

[0028]

As is apparent from the above description,
The conductive roller and the manufacturing method thereof according to the present invention have the following effects.

In the method for producing a conductive roller according to claim 1, the roller body is coated with a coating tank having a predetermined shape and size, leaving both ends not coated with a uniform coating solution. ,
Then, by applying the solvent to the part not coated with this coating liquid, the coating liquid and the solvent mix easily and swell on the edge of the coating film coated with the coating liquid. It is possible to obtain a conductive roller having a coating film that is substantially uniform over the entire length of the roller main body without causing the above. This eliminates the work of forming the roller body longer than a predetermined size to remove the bulge at the end of the coating film, which leads to a reduction in the amount of material.

According to a second aspect of the present invention, in the method of manufacturing a conductive roller, the coating tank is a parallelogram in plan view, and the inclined side of the coating tank is inclined with respect to the axial direction of the roller body. Three
By setting the angle to 0 ° or more, it is possible to eliminate the waviness of the surface of the coating film, which tends to occur when the roller body is separated from the coating liquid surface. Furthermore, the interval between the parallel sides is set to an interval corresponding to the width for applying the coating liquid of the roller body, and by moving the roller body while rotating it on the surface of the coating liquid, the both ends of the roller body can be made uniform. The coating is performed while leaving the portion (5 to 10 mm from both ends) where the coating liquid is not applied.

According to a third aspect of the present invention, there is provided a method of manufacturing a conductive roller, which comprises rotating a conductive roller and spraying a solvent onto a portion not coated with a coating liquid by a spray device. Since the solvent is applied uniformly over the entire circumference of the roller and can be applied by a simple spraying device, it can be easily attached to a narrow place near the application tank.

According to a fourth aspect of the present invention, there is provided a method of manufacturing a conductive roller, wherein MEK and DM are used as a solvent of the same kind as the solvent of the coating liquid applied to the portions of the roller body where the coating liquid is not applied.
Since F is applied, the solvent and the coating liquid are dispersed and mixed very quickly, and the coating film at the end of the roller body does not swell.

In the conductive roller according to the fifth aspect, the coating liquid is applied with the both ends of the roller body leaving a predetermined range, and the solvent is applied to the both ends to form the coating liquid. The solvents disperse and mix with each other, and no bulge occurs at the end of the coating film applied to the roller body, and the difference in thickness of the coating film between the center part and the end part of the roller body is 10 μm or less. As a result, when the conductive roller is attached to the photosensitive drum or the like, both are evenly contacted over the entire length, and a uniform image is obtained.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view of a conductive roller of the present invention, FIG. 1 (a) is an overall view, and FIG. 1 (b) is a partially enlarged sectional view of one end portion.

FIG. 2 shows a coating tank used in the method for producing a conductive roller of the present invention, FIG. 2 (a) is a plan view, and FIG.
FIG. 3 is a front view showing a partial cross section.

FIG. 3 is a plan view showing a positional relationship between a roller body being coated and a coating tank in the method for manufacturing a conductive roller of the present invention, FIG. Figure 3
3B is in the middle of coating, and FIG. 3C is immediately before the roller body is separated from the coating liquid.

FIG. 4 is a partial cross-sectional view illustrating movements of the solvent and the coating liquid after spraying the solvent 11 on the roller body end portion 12 in the method for manufacturing a conductive roller of the present invention.
FIG. 4A shows a state in which the solvent 11 is being sprayed, and FIG.
4B shows a state in which the solvent has adhered to the end portion 12 of the roller body, FIG. 4C shows a state in which a part of the coating liquid has transferred to the end portion 12, and FIG. This is the state in which the working fluid has been transferred and drying has been completed.

FIG. 5 is a partial cross-sectional view of an end portion of a conductive roller manufactured by a conventional manufacturing method.

6 is a measurement result of the thickness of the coating film of the conductive roller, FIG. 6 (a) is the thickness of the coating film of the conductive roller according to the present invention, and FIG. Is the thickness of the coating film of the conductive roller.

[Explanation of symbols]

1: Conductive roller 2: Roller body 3: Shaft 4: Coating film 4a: coating film end 5: Coating tank 6: Coating tank body 6a: parallel side 6b: inclined side 7: Gutter 8: Recovery pipe 9: Supply pipe 10: Spray 11: Solvent 12: Both ends of the roller body

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) G03G 15/16 103 G03G 15/16 103 (72) Inventor Hiroshi Izumi 3 Meiwado-dori, Hyogo-ku, Kobe-shi, Hyogo No. 2-15 F-term in Bando Kagaku Co., Ltd. (reference) 2H071 BA43 DA06 DA08 DA09 EA04 2H077 AD02 AD06 FA00 FA13 FA14 FA22 FA25 2H200 FA13 FA16 HA03 HB12 HB22 JA02 LC04 4F040 AA04 AB05 BA47 CC01 CC09 CC18

Claims (5)

[Claims] 1. A roller body, which is a conductive elastic body, is concentrically laminated on the outer circumference of a shaft body with a part of both ends left, and a coating film is formed so that the outer diameter is substantially equal over the entire outer circumference of the roller body. A method for manufacturing a conductive roller used in an electrophotographic apparatus, etc., in which a roller molded body is kept horizontal while being overflowed and stored in a coating tank that is inclined with respect to the moving direction. 5-10 from the starting end of the roller body
mm from the position where the coating solution is left and moved while rotating to leave a length of 5 to 10 mm from the end to apply the coating solution, and then the coating solution is applied to both ends where the coating solution is not applied. A method of manufacturing a conductive roller, which comprises applying the same type of solvent as above and drying the surface of the roller body. 2. A side edge of the coating tank is a parallelogram in a plan view, and an inclined side edge that is a side edge that is inclined and intersects in the roller movement direction is 30 ° or more in the axial direction of the roller molded body. 2. The conductive roller according to claim 1, wherein the intervals of the parallel sides, which are the sides parallel to the roller movement direction, intersect with each other at an angle corresponding to the width of the roller body for applying the coating liquid. Manufacturing method. 3. The conductive material according to claim 1, wherein the method of applying the solvent to both ends of the roller body not applied with the coating liquid is to apply the solvent by a spray device while rotating the roller body. Roller manufacturing method. 4. The method for producing a conductive roller according to claim 1, wherein the solvent applied to both ends of the roller body not coated with the coating liquid is methyl ethyl ketone, dimethyl formaldehyde, or a mixture thereof. . 5. A conductive roller such as a developing roller, a charging roller, and a transfer roller used in an electrophotographic apparatus or the like, which has a cylindrical shape made of a conductive elastic material on the outer periphery of a shaft body with a part of both ends left. The roller body and the coating liquid film are formed concentrically, and the coating liquid film in the central portion is guided to the axial end portion of the coating liquid film by a solvent to dry the roller central portion in the axial direction and both end portions. The outer peripheral difference is less than 10 μm.