JP2002031906A - Substrate for photosensitive drum and photosensitive drum using that substrate for photosensitive drum - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a substrate for a photosensitive drum such that the picture quality of a photosensitive drum using a resin substrate can be improved. SOLUTION: The substrate for a photosensitive drum is a pipe substrate made of a resin composition blended with a conducting agent and fibrous filler. The substrate consists of such a resin composition that the number of aggregates in >=10 μm size of the fibrous filler is <=25/mm2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylindrical substrate of a photosensitive drum used for an electrophotographic apparatus or an electrostatic recording apparatus, and a photosensitive drum using the substrate.

[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 resin pipe obtained by injection-molding a conductive resin composition obtained by mixing and dispersing a conductive agent such as carbon in a thermoplastic resin is used as a cylindrical substrate 1, and a photosensitive layer 3 is formed on the outer peripheral surface of the substrate 1 of the conductive resin pipe. Is applied to obtain a photosensitive drum. In this case, the resin composition constituting the base 1 is filled with a fibrous filler to improve the strength. When a resin base is used as described above, at least one of the flanges 2a and 2b is formed integrally with the resin base 1 by a resin. The drive gear 6 may be formed integrally with the integrally formed flange.

According to the photosensitive drum using the resin base, many processing steps required when the above-described aluminum alloy base is used can be omitted, and the weight of the photosensitive drum can be reduced. You can also plan. In addition, by forming the flange and the driving gear integrally with the base, conduction between the flange and the driving gear and the base can be performed extremely stably.

However, a photosensitive drum using this resin base may not always provide a satisfactory image quality, and it is desired to improve this point.

The present invention has been made in view of the above circumstances, and provides a photosensitive drum substrate capable of improving the image quality of a photosensitive drum using a resin substrate, and a photosensitive drum using the photosensitive drum substrate. The purpose is to provide.

[0011]

Means for Solving the Problems and Embodiments of the Invention The present inventors have made intensive studies to achieve the above object, and as a result, have obtained a photosensitive drum by forming a photosensitive layer on a resin base. In this case, it has been found that agglomerates of the fibrous filler compounded in the resin composition for forming the base for the purpose of improving the strength adversely affect the surface characteristics of the photosensitive drum and cause deterioration of image characteristics. . That is, the fibrous filler such as various whiskers used for the photosensitive drum substrate has an average fiber diameter of about 0.1 to 1 μm and an average fiber length of about 5 to 30 μm. At the time of the agglomeration of the fiber may be mixed, and when this agglomerate is exposed on the substrate surface portion, it adversely affects the surface properties such as surface properties and conductivity, which causes deterioration of image characteristics. I found that.

[0012] Therefore, as a result of further study, 10 μm
These relatively large agglomerates greatly affect image degradation,
This problem can be solved by limiting the abundance of such large aggregates. As a result of various studies, relatively large aggregates of 10 μm or more were found in the resin composition at 25 particles / mm ² or less. If so, the inventors have found that image deterioration due to the aggregates hardly occurs, and have completed the present invention.

Accordingly, the present invention provides a pipe-shaped substrate comprising a resin composition containing a conductive agent and a fibrous filler,
A photosensitive drum substrate comprising a resin composition having a number of aggregates of 10 μm or more of the fibrous filler of 25 μm / mm ² or less, and a photosensitive layer coated on an outer peripheral surface of a cylindrical substrate. The present invention provides a photosensitive drum characterized in that the photosensitive drum base is used as the cylindrical base in a photosensitive drum formed by processing.

Hereinafter, the present invention will be described in more detail.
The photosensitive drum substrate of the present invention is a pipe-shaped substrate made of a resin composition containing a conductive agent and a fibrous filler,
Aggregates of 10 μm or more of the fibrous filler mixed and dispersed in the resin composition are reduced to 25 particles / mm ² or less.

As the resin component constituting the above resin composition, a thermoplastic resin or a resin composition based on a thermoplastic resin is suitably used. In this case, as the thermoplastic resin, a known resin material conventionally used for a substrate for a photosensitive drum can be used. However, since it is particularly excellent in chemical resistance and mechanical strength, polyamide such as various nylons is used. Resins are preferably used. Among them, a polyamide resin obtained from meta-xylylenediamine and adipic acid and / or a polyamide resin obtained from ε-caprolactam are particularly preferably 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.

In the present invention, a plurality of resins may be mixed to form the molding material for the pipe. For example, the nylon MXD6 and / or the nylon 6 may be mixed with another resin. In this case, the other resin is not particularly limited, but nylon 11, nylon 1
2, it is preferable to use other polyamide resins such as nylon 46, nylon 66, nylon 610, nylon 612, nylon 1212, and copolymers thereof.
When these other resins are mixed, the mixing ratio is not particularly limited, but is at least 30 to 100% by mass, particularly 40 to 100% by mass in the resin component constituting the composition.
It is preferable that the mass% be the above-mentioned nylon MXD6, nylon 6, or a mixture thereof.

The conductive agent to be mixed in the resin composition may be any as long as it can be uniformly dispersed in the resin, such as carbon black, graphite, aluminum, copper, and the like. Metal powder such as nickel, conductive glass powder 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.
0 mass%, particularly preferably 5 to 20 mass%,
Thereby, the surface resistance value of the resin pipe is preferably set to 10 ⁴ Ω / □ (ohm / square) or less, particularly preferably 10 ² Ω / □ or less.

Further, as the fibrous filler compounded in the resin composition, carbon fibers, conductive whiskers,
Conductive fibers such as conductive glass fibers, whiskers, and non-conductive fibers such as glass fibers can be used. In this case, the conductive fiber can also function as a conductive agent, and the use of the conductive fiber can reduce the amount of the conductive agent used. Specific examples of these fibrous fillers include potassium titanate whiskers, calcium metasilicate whiskers, and magnesium oxalphate whiskers, and one or more of these can be used in combination. Of these, potassium titanate whiskers are particularly preferably used.

The size of the fibrous filler is not particularly limited, but the average fiber diameter is 0.1 to 5 μm and the fiber length is 5 to 30 μm, particularly the average fiber diameter is 0.3 to 0.7 μm and the fiber length is When the fiber diameter is less than 0.1 μm or the fiber length is less than 5 μm, the reinforcing effect is reduced, and the elastic modulus and mechanical strength of the molded product may be reduced. When the diameter exceeds 5 μm or the fiber length exceeds 20 μm, the smoothness of the surface of the molded product is impaired, and as a result, product characteristics such as image characteristics may be reduced.

The amount of the fibrous filler is appropriately selected depending on the strength required for the pipe, the type of the filler used, the length and diameter of the fiber, and is not particularly limited. 5 to 40% by mass of the resin composition, especially 10 to 3%
It is preferably about 0% by mass, more preferably about 15 to 20% by 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. In the case of the potassium titanate whisker preferably used as the fibrous filler, the content is preferably 5 to 30% by mass, particularly preferably 15 to 20% by mass.

The substrate for a photosensitive drum of the present invention controls the agglomerates of the fibrous filler, and the number of agglomerates of 10 μm or more present in the resin composition is 25 / mm ² or less, preferably 10 / mm ² or less.

The method for controlling the agglomerates of the fibrous filler as described above is not limited. For example, the following methods are used: the fibrous filler is passed through an appropriate mesh filter to remove large agglomerates; And a method in which the kneading conditions for kneading with the resin are set to the strong kneading conditions in which the shearing force is increased to pulverize the agglomerates to increase the dispersibility. Can be.

In the above resin composition, polytetrafluoroethylene (PTFE), silicone, molybdenum disulfide (MoS ₂ ), and various metal soaps may be used, if necessary, in addition to the conductive agent and the fibrous filler. And other known additives 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.

The method for molding a resin pipe using the above resin composition is not particularly limited, and may be a known method such as an injection molding method or an extrusion molding method. Usually, the injection molding method is preferably employed. Is done. In this case, the above-mentioned conductive agent, fibrous and other additives may be mixed into the resin at the time of molding, but usually, these are mixed in advance and extruded to form resin pellets molded to a predetermined size. Preferably, the resin pellet is subjected to injection molding or extrusion molding for molding a resin pipe. At this time, the agglomerates of the fibrous filler are preferably controlled in the above-described range in the state of the resin pellets. Can be obtained. In addition, the existence rate of the agglomerate can be confirmed by observing the cross section of the resin pellet.
It can be confirmed by observing an EM-Compo image (backscattered electron image).

The photosensitive drum substrate of the present invention is, for example, shown in FIG.
The photosensitive layer 3 is formed on the surface similarly to the cylindrical substrate 1 shown in FIG.

In this case, in the photosensitive drum of FIG. 1, flanges 2a and 2b formed separately are fitted and fixed to both end surfaces of the cylindrical base 1. At least one of the flanges 2a and 2b is connected to the resin pipe. It can also be formed integrally with the cylindrical substrate 1 made of. 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.

The substrate for a photosensitive drum of the present invention is formed as a photosensitive drum by coating and forming a photosensitive layer on the outer peripheral surface of the resin pipe. The photosensitive layer is formed by coating with a known material and method. And the layer configuration may be a known configuration. Other configurations can be the same as those of a normal photosensitive drum.

[0029]

The present invention will now be described more specifically with reference to examples. [Examples 1 to 4 and Comparative Example] A resin pellet having a diameter of 2 mm x 3 mm was prepared by kneading and extruding a resin composition having the following composition. At this time, the following G, H, K, M
, And the four types of resin pellets shown in Table 1 were prepared. For each resin pellet, a cross section was obtained by a microtome, and a FESEM-Compo image (reflection electron image) was observed to measure the abundance of 10 μm or less aggregates of potassium titanate whiskers. Table 1 shows the results.

Material composition Nylon 66 (UBE nylon / Ube Industries) 60% by weight Nylon 6 (UBE nylon / Ube Industries) 10% by weight Carbon black (Ketjen black / Lion) 10% by weight potassium titanate Whisker 20% by mass (average fiber diameter 0.5 μm, fiber length 15 μm)

Aggregate removal treatment G: One treatment with an aggregate removal filter in the fiber production process. Treatment H: Treated twice with an aggregate removal filter in the fiber production process. Treatment K: Treated three times with an aggregate removal filter in the fiber production process. Treatment M: In the fiber production process, treatment was performed four times with an aggregate removal filter.

Using the above resin pellets as a molding material,
A resin pipe was formed by injection molding. Using the obtained resin pipes as bases, on the outer peripheral surface, a charge generation layer is applied using a paint obtained by dissolving a polyester resin containing a phthalocyanine-based pigment in chloroform, and further converting a polycarbonate resin containing a hydrazone-based compound into chloroform. The charge transport layer was coated with the dissolved paint to form a photosensitive layer having a thickness of 30 μm, thereby forming a photosensitive drum. The obtained photosensitive drum was mounted on a laser printer, and an image output test was performed under the following conditions. Table 1 shows the results.

[0033]

[Table 1]

As shown in Table 1, the photosensitive drum of the present invention in which the number of agglomerates having a predetermined size or more is controlled can effectively prevent the occurrence of black spots and obtain a good image. Was confirmed.

[0035]

As described above, according to the photosensitive drum substrate of the present invention, by controlling the agglomerates of the fibrous filler present in the resin composition forming the substrate, the photosensitive drum can be formed. Image quality can be improved.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a general configuration of a photosensitive drum.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylindrical substrate (substrate for photosensitive drum) 2, 2a, 2b Flange 3 Photosensitive layer 4 Support shaft 5 Shaft hole 6 Drive gear

Claims (5)

[Claims] 1. A resin containing a conductive agent and a fibrous filler.
A pipe-like substrate comprising the composition, wherein the fibrous filler is
The number of aggregates of 10 μm or more is 25 / mm ^TwoBelow
For a photosensitive drum, comprising a resin composition comprising:
body. 2. The photosensitive drum substrate according to claim 1, wherein the fibrous filler is a potassium titanate whisker. 3. The photosensitive drum substrate according to claim 1, wherein the amount of the fibrous filler is 5 to 30% by mass of the resin composition. 4. A pipe-shaped substrate obtained by injection molding a resin pellet in which the conductive agent and the fibrous filler are mixed and dispersed as a molding material, wherein the number of aggregates of 10 μm or more of the fibrous filler is 25 / mm. photosensitive drum substrate according to any one of claims 1 to 3 is obtained using the ² following resin pellets. 5. A photosensitive drum having a photosensitive layer formed by coating a photosensitive layer on an outer peripheral surface of a cylindrical substrate, wherein the photosensitive drum substrate according to any one of claims 1 to 4 is used as the cylindrical substrate. A photosensitive drum.