JP2001252945A - Resin pipe manufacturing method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resin pipe manufacturing method capable of manufacturing a resin pipe with extremely good dimensional accuracy and suitably used in the manufacture of the resin pipe, wherein high dimensional accuracy is required in a case obtaining the substrate of a photosensitive drum used in an electrophotographic apparatus such as a copier, a facsimile or a printer. SOLUTION: In a method for manufacturing the resin pipe by injection- molding a thermoplastic resin or a resin composition based on the thermoplastic resin, a molded article is demolded from a mold to be subjected to annealing treatment.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a resin pipe with extremely high dimensional accuracy, and a method for manufacturing a photosensitive drum base used in an electrophotographic apparatus such as a copying machine, a facsimile, and a printer. The present invention relates to a method for manufacturing a resin pipe which can be suitably used for manufacturing a resin pipe requiring accuracy.

[0002]

2. Description of the Related Art In an electrostatic recording process in a copying machine, a facsimile, a printer, or the like, first, the surface of a photosensitive drum is charged uniformly.
An electrostatic latent image is formed by projecting an image from the optical system on the surface of the photosensitive drum to eliminate the charging of the portion exposed to the light, and then supplying toner to the electrostatic latent image to supply the electrostatic latent image with toner. A toner image is formed by the objective adhesion,
Printing is performed by transferring the image onto a recording medium such as P, photographic paper, or the like.

As a photosensitive drum used in such an electrostatic recording process, a photosensitive drum having a structure shown in FIG. 1 has been generally used.

[0004] That is, generally used are those in which flanges 2a and 2b are fitted and fixed to both ends of a cylindrical substrate 1 having good conductivity, and a photosensitive layer 3 is formed on the outer peripheral surface of the cylindrical substrate 1. Usually, as shown in FIG. 1, the photosensitive drum has support shafts 4, 4 provided on a main body a of the electrophotographic apparatus, and shaft holes 5, provided on both flanges 2a, 2b.
5 and rotatably supported, and one flange 2
The gear 7 connected to a driving source such as a motor meshes with the driving gear 6 formed in the section b, and is driven to rotate.

In this case, as a material for forming the cylindrical substrate 1, an aluminum alloy has been conventionally used because it is relatively lightweight, has excellent machinability, and has good conductivity.

However, cylindrical substrates made of an aluminum alloy must be individually machined with high precision in order to satisfy strict dimensional accuracy requirements and predetermined surface roughness. , 2b to be fitted and fixed, and in some cases, processing to prevent oxidation of the surface is required. For this reason, there is a problem that the number of manufacturing steps is increased and the manufacturing cost is increased, and the aluminum alloy is not always satisfactory as a material for the cylindrical base constituting the photosensitive drum.

On the other hand, a conductive resin composition in which a conductive agent such as carbon black is mixed and dispersed in a thermoplastic resin is injection-molded to obtain a photosensitive drum base made of a resin pipe.

According to this resin drum base, many processing steps required for obtaining the above-mentioned aluminum alloy drum base can be omitted, and the production cost can be greatly reduced. In addition, the weight of the obtained substrate can be reduced.

However, a resin pipe obtained by injection-molding a thermoplastic resin or a resin composition based on a thermoplastic resin undergoes a dimensional change over time after molding, resulting in extremely high dimensional accuracy. The required photosensitive drum substrate is not always satisfactory in terms of dimensional stability.

The present invention has been made in view of the above circumstances, and provides a resin pipe which has excellent dimensional stability and can be suitably used for applications requiring high dimensional stability such as a photosensitive drum substrate. The purpose is to:

[0011]

Means for Solving the Problems and Embodiments of the Invention As a result of intensive studies to achieve the above object, the present inventor has found that when the molten resin gradually solidifies, it is most likely that the molecule is solidified in the process of solidification. In order to achieve a stable crystal structure, in the case of injection molding, as a result of the resin component entering the mold cavity and rapidly cooling, the orientation is prevented before reaching a stable state. Then, it was found that the resin pipe after molding caused a dimensional change with time due to the stabilization of the residual stress in that portion.

In order to cope with this phenomenon, further investigations have been made. As a result, the molded product removed from the injection mold is annealed under conditions suitable for reorienting the molecules. The above-mentioned residual stress is released, a stable crystalline state can be formed, dimensional change is prevented as much as possible, and even in applications requiring high dimensional accuracy such as a photosensitive drum substrate. The present inventors have found that a resin pipe having excellent dimensional stability which can be sufficiently applied can be obtained, and the present invention has been accomplished.

Accordingly, the present invention relates to a method for manufacturing a resin pipe by injection molding a thermoplastic resin or a resin composition based on a thermoplastic resin. And a method for manufacturing a resin pipe.

Hereinafter, the present invention will be described in more detail.
The method for producing a resin pipe of the present invention is to obtain a resin pipe by injection molding a thermoplastic resin or a resin composition based on a thermoplastic resin as described above, and to perform an annealing treatment under specific conditions. is there.

In this case, the thermoplastic resin or the resin composition based on the thermoplastic resin may be any one as long as it can be formed into a pipe by an injection molding method.
Although it can be appropriately selected according to the application of the resin pipe to be manufactured, in particular, when obtaining a resin pipe used as a substrate for a photosensitive drum, it has good surface smoothness for forming a photosensitive layer, and has a mechanical property. Polyamide resins such as various nylon resins are preferably used because a resin pipe having excellent strength can be obtained. Among them, since the dimensional stabilization by the annealing treatment is remarkable, a polyamide resin obtained from meta-xylylenediamine and adipic acid, a polyamide resin obtained from ε-caprolactam, a polyamide resin and a water absorption of 0.3% or less At least one selected from alloy resins blended with a resin can be suitably used.

The polyamide resin produced by the polycondensation reaction between metaxylylenediamine and adipic acid is generally called nylon MXD6, and the polyamide resin obtained by a ring-opening polymerization reaction of ε-caprolactam. The resin is generally called nylon 6.

Further, an alloy resin obtained by blending the polyamide resin of the present invention with a resin having a water absorption of 0.3% or less,
It can be suitably used for the following reasons.

That is, although it has been proposed to form a cylindrical substrate with a conductive resin based on a polyamide resin, these polyamide resins (PA) are made of PA6.
6 and PA6, etc., have a high water absorption and a water absorption rate (AST
According to MD 570), PA66 is about 0.6
３3%, PA6 is about 0.7-1.8%, which is relatively higher than other resins. For this reason, there may be a problem in maintaining the dimensional accuracy of the product.
Under high-temperature and high-humidity conditions such as, dimensional expansion may occur due to water absorption even when exposed for about 2 to 3 hours. For this reason, the function of the photoconductor may be affected, and as a result, the image quality may be significantly affected.

Therefore, in the present invention, a resin having a high water absorption such as polyamide resin has a water absorption of 0.3%.
% Or less, and the alloy is used as a base material. The material has a low water absorption and can be provided with a property of little dimensional change even in a high temperature and high humidity environment.

As the polyamide resin to be blended, known resins can be used, and specifically, nylon MX
D6, nylon 6, nylon 11, nylon 12, nylon 46, nylon 66, nylon 610, nylon 6
12, polyamide 1212, and other polyamide resins such as copolymers thereof, and are not particularly limited.

Resins having a water absorption of 0.3% or less (hereinafter referred to as blending resins) blended with the above polyamide include PP (polypropylene), PPE
(Polyphenylene ether), PPS (polyphenylene sulfide) and the like.
S and PPE are more preferably PPE.

The polyamide resin of the present invention has a water absorption of 0.3
% In order to obtain an alloy resin blended with the resin of not more than 1% by mass, usually 1 to 70% by mass, preferably 5 to 50% by mass, Preferably, it can be obtained by blending so as to be 10 to 40% by mass.

In the above blending, both resin components are used to further improve the compatibility between the polyamide resin and the blended resin to enhance dispersibility, and to improve mechanical properties such as strength, water absorption and chemical resistance. A compatibilizing agent having a high affinity for is suitably used. Examples of the compatibilizer include maleic acid-modified polypropylene (maleic acid-modified PP), PA-PPS-based, and P-PP-based.
For the A-PPE system, epoxy-modified polystyrene (epoxy-modified PS) -polymethyl methacrylate (P
MMA) copolymer and the like.

The polyamide resin of the present invention has a water absorption of 0.3
%, As described above, has excellent dimensional stability as compared with a molded product using another polyamide resin alone as a resin component. A reference example comparing this point is shown in the following table. Table 1 below
The water absorption and dimensional change shown in the above are the differences between before and after standing for 24 hours in a high-temperature and high-humidity tank under a 50 ° C-95% RH environment, and by blending a polyamide resin with a resin having a low water absorption, It is recognized that the water absorption and the dimensional change of the molded article under a high temperature and high humidity environment are dramatically improved.

[0025]

[Table 1]

In the present invention, a plurality of resins may be mixed to form a molding material. The molding material may be selected from the group consisting of nylon MXD6, nylon 6, and an alloy resin blended with a polyamide resin and a resin having a water absorption of 0.3% or less. At least one of these resins may be mixed with another resin. In this case, the other resin is not particularly limited, but may be nylon 11, nylon 12, nylon 46, nylon 66, or the like.
Nylon 610, nylon 612, nylon 1212,
It is preferable to use another polyamide resin such as a copolymer thereof. When these other resins are mixed, the mixing ratio is not particularly limited, but at least 30 to 100% by mass, particularly 40 to 100% by mass of the nylon MXD6,
It is preferable to use at least one selected from an alloy resin blended with nylon 6, a polyamide resin and a resin having a water absorption of 0.3% or less, or a mixture thereof.

When the obtained resin pipe is used for applications requiring conductivity, such as a substrate for a photosensitive drum, a conductive resin composition is obtained by adding a conductive agent to the above-mentioned thermoplastic resin to impart conductivity. be able to.

In this case, any conductive agent may be used as long as it can be uniformly dispersed in the resin, and examples thereof include carbon black, graphite, and the like.
Metal powders such as aluminum, copper, nickel and the like, conductive glass powders and the like can be mentioned, and it is particularly preferable to use carbon black. The amount of the conductive agent to be added is not particularly limited, but is preferably 5 to 30% by mass, more preferably 5 to 20% by mass of the composition when used as a substrate for a photosensitive drum. It is recommended that the surface resistance be 10 ⁶ Ω / □ (ohm / square) or less, especially 10 ⁵ Ω / □ or less, and preferably 10 ⁴ Ω / □ or less.

Furthermore, inorganic fillers such as various fibers can be blended with the thermoplastic resin for the purpose of reinforcing and increasing the amount. As the inorganic filler, conductive fibers such as carbon fibers, conductive whiskers, and conductive glass fibers, and non-conductive fibers such as whiskers and glass fibers can be used. In this case, the conductive fiber can also act as a conductive agent, and by using the conductive fiber,
The amount of the conductive agent used can be reduced.

The amount of the filler is appropriately selected depending on the strength required for the resin pipe, the type of the filler used, the length and the diameter of the fiber, and the like, and is not particularly limited. 1 to 30% by mass of the product, more preferably 5%
It is preferably set to と す る 25 mass%, more preferably 10 to 25 mass%. In this case, by adding such a filler, the strength and rigidity of the molded article can be effectively improved without lowering the surface smoothness.

The thermoplastic resin of the molding material may include, if necessary, polytetrafluoroethylene (PTFE), silicone, molybdenum disulfide (MoS ₂ ), various metal soaps, etc., in addition to the above-mentioned conductive agent and filler. Can be added in an appropriate amount. The conductive agent and the filler may be subjected to a surface treatment using a commonly used silane coupling agent or titanate coupling agent.

According to the production method of the present invention, the thermoplastic resin or the thermoplastic resin composition is injection molded to obtain a resin pipe such as a substrate for a photosensitive drum. In this case, molding conditions such as molding temperature and injection pressure can be set to normal conditions according to the molding material to be used.

In this case, in the present invention, the molded product is released from the mold and then subjected to an annealing treatment to improve the dimensional stability of the obtained resin pipe.

Here, the annealing treatment is performed by heating or heating the molded product removed from the mold by a heating device such as a thermostat. In this case, the processing conditions are appropriately selected according to the molding material, and are not particularly limited. However, usually, the processing temperature is 100 to 140 ° C., particularly 100 to 130 ° C., and the processing time is 0. It is preferably carried out by heating or heating for about 0.5 to 2 hours, especially about 1 to 1.5 hours. If the processing temperature is low, the stress release may be insufficient due to the resin material, or it may take a long time exceeding 5 hours to perform sufficient annealing. On the other hand, if the temperature is higher than 140 ° C., decomposition of the resin due to heat,
Deformation or the like may occur, which may cause a bad influence on the molded product.

More specifically, for example, as a resin component of a molding material, a polyamide resin obtained from the above meta-xylylenediamine and adipic acid, a polyamide resin obtained from ε-caprolactam, and a polyamide resin have a water absorption of 0.1%. When at least one selected from an alloy resin blended with 3% or less of a resin, the treatment temperature is 100 to 140 ° C, preferably 100 to 125 ° C, more preferably 115 to 120 ° C. Time 0.5 ~
It is recommended that the annealing be performed for 2 hours, particularly 1 to 1.5 hours, so that stress can be reliably released and a stable crystal structure can be achieved.

The production method of the present invention is suitably applied to the production of resin pipes (cylindrical substrates) which require high dimensional accuracy, such as photosensitive drum substrates.

In this case, in the photosensitive drum of FIG. 1, the flanges 2a and 2b formed separately are fitted and fixed to both end surfaces of the cylindrical base 1, and at least one of the flanges 2a and 2b is the present invention. Can be formed integrally with the cylindrical substrate 1. Further, by adding the reinforcing inorganic filler, a molded product having excellent strength and rigidity can be obtained, so that the driving gear 6 can be integrally formed together with the flange.

When the obtained resin pipe is used as a substrate for a photosensitive drum, the outer peripheral surface thereof has a center line average roughness Ra of 0.8 μm or less, particularly 0.2 μm or less.
The maximum height Rmax is 1.6 μm or less, particularly 0.8 μm or less, and the 10-point average roughness Rz is 1.6 μm or less, particularly 0.8.
μm or less.
If x and Rz are too large, irregularities on the surface of the cylindrical substrate 1 will appear on the photosensitive layer 3, which may cause image defects. As a molding material, a polyamide resin obtained from the above meta-xylylenediamine and adipic acid, a polyamide resin obtained from ε-caprolactam, and an alloy resin obtained by blending a polyamide resin and a resin having a water absorption of 0.3% or less are used. By using at least one selected member, even when an inorganic filler for reinforcement is added, such surface roughness can be easily achieved.

The photosensitive drum 3 is formed by forming the photosensitive layer 3 on the outer peripheral surface of the base 1 made of the resin pipe. In this case, the photosensitive layer 3 can be formed by a known material and composition. Also, the layer configuration may be a known configuration.

The resin pipe obtained by the production method of the present invention is suitably used as a substrate of a photosensitive drum requiring high dimensional accuracy, but the application is not limited to this.

[0041]

The present invention will now be described more specifically with reference to examples and comparative examples, but the present invention is not limited to the following examples.

Examples 1 and 2 and Comparative Example 1 A conductive resin composition having the following composition was prepared according to a conventional method and had an outer diameter of 30%.
A cylindrical substrate for a photosensitive drum having a thickness of 230 mm, a length of 230 mm and a thickness of a peripheral wall of 2 mm was formed by an injection molding method. Note that molding was performed using the same mold under the same molding conditions.

The obtained molded article was subjected to an annealing treatment only in Examples according to the description in Table 2, and the change in size with time was examined. The results are also shown in Table 2. Conductive composition composition Nylon 66 (Mitsubishi Engineering Plastics “Novamid”) 50% by mass C / B (Lion “Ketjen Black”) 15% by mass Potassium titanate whisker fiber (Otsuka Chemical “Dentol”) 15% by mass Nylon MXD6, Mitsubishi engineering plastic “Lenny” 20% by mass

[0044]

[Table 2]

From the results shown in Table 2, it was confirmed that the photosensitive drum substrate manufactured by the method of the present invention, after being subjected to the annealing treatment, exhibited a small dimensional change after molding and was excellent in dimensional stability. Was.

[0046]

According to the production method of the present invention, a resin pipe which is lightweight, has excellent strength, has excellent dimensional stability, and is preferably used as a substrate for a photosensitive drum can be obtained easily and reliably.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view illustrating an example of a photosensitive drum.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylindrical base 2a, 2b Flange 3 Photosensitive layer 4 Support shaft 5 Shaft hole 6 Drive gear

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification code FI Theme coat ゛ (Reference) C08K 3/04 C08K 3/04 C08L 77/00 C08L 77/00 101/00 101/00 F16C 13/00 F16C 13/00 EZ G03G 5/10 G03G 5/10 A // B29K 77:00 B29K 77:00 103: 04 103: 04 105: 12 105: 12 B29L 31:34 B29L 31:34

Claims (8)

[Claims] 1. A method for producing a resin pipe by injection molding a thermoplastic resin or a resin composition based on a thermoplastic resin, wherein the molded article is released from a mold and then subjected to an annealing treatment. A method for manufacturing a resin pipe. 2. The resin composition according to claim 1, wherein the resin component is a polyamide resin obtained from meta-xylylenediamine and adipic acid, a polyamide resin obtained from ε-caprolactam, a polyamide resin and a resin having a water absorption of 0.3% or less. At least one selected from alloy resins blended with
The method for producing a resin pipe according to claim 1, wherein the resin pipe contains a seed. 3. The method according to claim 1, wherein the annealing is performed at a temperature of 100 to 14.
The method is carried out under the conditions of 0 ° C and a treatment time of 0.5 to 2 hours.
Or the method for producing a resin pipe according to 2. 4. The method for manufacturing a resin pipe according to claim 1, wherein a conductive resin pipe is obtained by injection molding a conductive resin composition in which a conductive agent is mixed and dispersed in a thermoplastic resin. . 5. The method according to claim 4, wherein the conductive resin composition contains carbon black as a conductive agent. 6. The method for producing a resin pipe according to claim 5, wherein the content of carbon black is 5 to 30% by mass. 7. The method according to claim 1, wherein the resin composition comprises one inorganic reinforcing filler.
2. A mixture dispersed and dispersed at a ratio of from 30% by mass to 1% by mass.
7. The method for producing a resin pipe according to any one of items 6 to 6. 8. The method for producing a resin pipe according to claim 1, wherein the resin pipe is a base for a photosensitive drum.