JP2002031908A - Substrate for photosensitive drum, photosensitive drum using that substrate for photosensitive drum and method for manufacturing 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 consists of a synthetic resin pipe and has a great number of recesses and projections in minute stripes along the axial direction on the outer surface of the pipe.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0011]

Means for Solving the Problems and Embodiments of the Invention In order to achieve the above-mentioned object, the present invention has been studied as a result of forming a photosensitive layer on a resin substrate to obtain a photosensitive drum. It has also been found that the higher the smoothness of the surface of the substrate, the higher the image quality cannot be obtained, and that the presence of appropriate irregularities on the surface of the substrate has a better effect on the improvement of the image quality. That is, a photosensitive layer is provided on the substrate of the photosensitive drum, and a transparent layer having a thickness of about 20 to 30 μm exists on the surface. At the time of exposure, two surfaces, the surface of the transparent layer and the lowermost surface (interface with the substrate), are provided. If there is a reflective surface and the smoothness of the substrate surface is very high, the two reflective surfaces interfere with light beams having the same direction but different optical path lengths, resulting in a reduction in image quality, and a It has been found that by forming moderate irregularities, the light is diffusely reflected and the direction of the light is scattered, so that the image quality can be improved by effectively preventing the image quality from deteriorating due to the interference.

The present inventor has further studied and found that, when forming moderate irregularities on the outer peripheral surface of the cylindrical resin substrate, if the irregularities are streaky irregularities along the axial direction of the substrate. It has been found that it is relatively easy to form countless fine irregularities suitable for improving the image quality. That is, when a pipe-shaped molded product is injection-molded and the molded product is removed from the mold, the molded product is removed from the cylindrical cavity of the mold by pulling the molded product in the axial direction. By appropriately roughening the outer peripheral surface of the molded product at the time, an infinite number of minute streaky irregularities along the axial direction are formed on the outer peripheral surface of the molded product, and moderate irregularities suitable for achieving the above object Have been found to be able to be formed on the surface of a molded product, and the present invention has been completed.

Accordingly, the present invention provides a photosensitive drum substrate, a photosensitive drum, and a method of manufacturing the photosensitive drum substrate described below. : A photosensitive drum base, in which a myriad of irregularities formed of minute streaky convex portions and concave portions along the axial direction are formed on an outer peripheral surface of a synthetic resin pipe innumerably. A photosensitive drum in which a photosensitive layer is applied and formed on the outer peripheral surface of a cylindrical substrate, wherein the photosensitive drum substrate is used as the cylindrical substrate. : A cylindrical core is placed in a cylindrical cavity of a mold, and a molten resin material is injected and injected between the core and the inner peripheral surface of the cavity to form a pipe-like molded product. When the molded article is pulled out of the mold and removed from the mold to obtain a photosensitive resin substrate made of a synthetic resin, when the pipe-shaped molded article is pulled out from the cavity, the outer peripheral surface of the molded article extends along the axial direction. A method for producing a substrate for a photosensitive drum, wherein the substrate for a photosensitive drum is obtained by forming minute streaky irregularities.

Hereinafter, the present invention will be described in more detail.
As described above, the photosensitive drum substrate of the present invention is formed on the outer peripheral surface of the synthetic resin pipe by forming innumerable irregularities formed of minute streaky convex portions and concave portions along the axial direction. is there.

As the resin material forming the pipe,
Although not particularly limited, a thermoplastic resin or a resin composition based on a thermoplastic resin is preferably 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.

In general, a conductive agent is added to the above-mentioned thermoplastic resin to impart appropriate conductivity. In this case, any conductive agent may be used as long as it can be uniformly dispersed in the resin. For example, metal powder such as carbon black, graphite, aluminum, copper, and nickel, and conductive glass powder Etc., but it is particularly preferable to use carbon black. The amount of the conductive agent to be added is not particularly limited.
-30% by mass, particularly preferably 5-20% by mass, whereby the surface resistance of the resin pipe is 10 ⁴ Ω / □.
(Ohm / square) or less, particularly preferably 10 ² Ω / □ or less.

Further, an inorganic filler such as various fibers can be blended with the resin material for the purpose of reinforcing or increasing the amount. As the inorganic filler, conductive fibers such as carbon fibers, conductive whiskers, and conductive glass fibers, and 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.

The compounding amount of these fillers is appropriately selected according to the strength required for the pipe, the type of the filler used, the length and diameter of the fiber, etc., and is not particularly limited.
Usually 1 to 30% by weight of the composition, more preferably 5 to 2%
It is preferably about 5% by mass, more preferably about 10 to 25% 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.

The resin material forming the pipe may include, as necessary, polytetrafluoroethylene (PTFE), silicone, molybdenum disulfide (MoS ₂ ), various metallic soaps, in addition to the above-mentioned conductive agent and 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 photosensitive drum substrate according to the present invention has an infinite number of irregularities formed of fine streaks and concave portions along the axial direction formed on the outer peripheral surface of the resin pipe. In this case, the streaked convex portions and concave portions may be formed substantially along the axial direction of the pipe, and may be meandering or oblique. The cross-sectional shape, size, depth, number, and the like of these convex portions and concave portions are not particularly limited. However, the surface roughness of the pipe outer peripheral surface due to these convex portions and concave portions is 0.1 mm in center line average roughness Ra. 01 to 0.2 μm, especially 0.03 to 0.
07 μm, and the maximum height Rmax is preferably 0.1 to 0.8 μm, particularly preferably 0.4 to 0.7 μm. these,
Ra and Rmax can be appropriately changed depending on the thickness of the photosensitive layer formed on the outer peripheral surface of the resin pipe, and are not necessarily limited to the above ranges.
If Rmax is too large, irregularities on the surface of the resin pipe will appear on the photosensitive layer, which may cause image defects. On the other hand, if Rmax is too small, light cannot be sufficiently scattered, and image interference due to light interference occurs. In some cases, the object of the present invention cannot be achieved.

The method of molding the resin pipe may be extrusion molding or injection molding, but the injection molding method is preferably used because a pipe having excellent dimensional accuracy can be molded with high productivity. Also, there is no limitation on the method of forming the above-mentioned streaky irregularities on the surface of the resin pipe, and streaky irregularities along the axial direction are formed on the inner peripheral surface of the cavity of the molding die, and this shape is formed at the time of molding. The streaks and projections may be transferred to the pipe surface or formed mechanically by grinding or the like after molding, but when the resin pipe molded by injection molding is removed from the mold, the cylindrical mold of the mold is used. By pulling out the pipe from the tee, it is preferable to form the above-mentioned streak-like irregularities by roughening the surface so as to damage the outer peripheral surface of the pipe at this time. It can be easily formed along the axial direction of the pipe.

For example, the photosensitive drum substrate of the present invention can be manufactured by injection molding according to the method shown in FIG. That is, as shown in FIG. 2A, a gate b1 for injecting and injecting molten resin is provided on one end surface of a first movable mold a having a cylindrical cavity a1 whose both ends are open. A mold b is arranged and joined, and a second movable mold c having a columnar core c1 is arranged and joined to the other end surface of the first movable mold a with the core c1 inserted into the cylindrical cab a1. The molten resin is injected and injected through the gate b1 into a cylindrical cavity formed between the outer peripheral surface of the core c1 and the inner peripheral surface of the columnar cavity a1. After the molding, first, as shown in FIG. 2B, the second movable mold c is separated from the first movable mold a, and the core c1 is removed from the resin pipe d. As shown in C), the first movable mold a is It separated from serial stationary die b, demolded as pull the plastic pipe d while holding the stationary die b from the cavity a1 of the first movable mold a. Then, as shown in FIG. 2D, the obtained resin pipe d is removed from the movable mold b together with the gate part d1,
By cutting and removing the gate portion d1, a resin pipe d is obtained.

In this case, the first type shown in FIG.
When the resin pipe d is pulled out of the cavity a1 of the movable mold a, the resin pipe d is drawn by the inner peripheral surface of the cavity a1.
May be formed on the surface of the resin pipe d along the axial direction so as to damage the surface of the resin pipe d. According to this method, minute streaky irregularities are formed on the outer peripheral surface of the resin pipe d by, for example, forming the minute irregularities by appropriately roughening the inner peripheral surface of the cavity a1 of the first movable die a. It can be easily formed.

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. In this case, the thickness of the photosensitive layer is not particularly limited and can be appropriately adjusted.
0 μm, particularly preferably 20 to 40 μm. If the thickness is less than 10 μm, the above-mentioned streaky irregularities on the substrate surface will be transferred to the surface of the photosensitive layer, and the surface smoothness of the photosensitive layer will be impaired. On the other hand, if the thickness exceeds 50 μm (the function of generating and moving the charge of the photosensitive agent may be impaired, thereby deteriorating the image quality. Other configurations may be the same as those of a normal photosensitive drum. .

[0029]

The present invention will now be described more specifically with reference to examples. A resin composition having the following composition was prepared, and a resin pipe was formed according to the above-described process shown in FIG. At this time, the cavity a1 of the first working mold a in FIG.
When the resin pipe d was pulled out of the resin pipe, streaky irregularities composed of minute convex parts and concave parts along the axial direction were formed on the surface of the resin pipe d. When the surface roughness of this resin pipe was measured, the center line average roughness Ra was 0.04 μm and the maximum height R
The maximum was 0.5 μm. Resin composition Nylon 66 (UBE nylon / Ube Industries, Ltd.) 60% by weight Nylon 6 (UBE nylon / Ube Industries, Ltd.) 10% by weight Carbon black (Ketjen black / Lion Corporation) 10% by weight Potassium titanate whisker Stud / Otsuka Chemical Co., Ltd.) 20% by weight

Using the obtained resin pipe as a substrate, a charge generation layer is applied to the outer peripheral surface thereof using a coating solution obtained by dissolving a polyester resin containing a phthalocyanine pigment in chloroform, and further a polycarbonate resin containing a hydrazone compound. Was dissolved in chloroform to form a photosensitive layer having a thickness of 30 μm by coating the charge transport layer with a coating solution of chloroform. The obtained photosensitive drum was mounted on a laser printer and an image output test was performed. As a result, a very clear and high-quality image was obtained.

[0031]

As described above, according to the photosensitive drum substrate of the present invention, the surface of the substrate reaches the substrate surface by the minute irregularities formed on the surface of the photosensitive drum along the axial direction. By scattering the generated light, it is possible to prevent deterioration of the image quality due to light interference as much as possible and to improve the image quality.

[Brief description of the drawings]

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

FIG. 2 is an explanatory view showing one example of a method for manufacturing a photosensitive drum substrate of the present invention.

[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 (4)

[Claims] 1. A photosensitive drum substrate comprising a synthetic resin pipe formed on a peripheral surface of a pipe made of synthetic resin innumerably with irregularities formed of minute streaky projections and depressions along an axial direction. 2. The surface roughness of the outer peripheral surface is adjusted to a center line average roughness Ra of 0.01 to 0.2 and a maximum height Rmax of 0.1 to 0.8 by the streaky irregularities. Characteristic substrate for photosensitive drum. 3. A photosensitive drum formed by coating a photosensitive layer on the outer peripheral surface of a cylindrical substrate, wherein the substrate for a photosensitive drum according to claim 1 or 2 is used as the cylindrical substrate. Photosensitive drum. 4. A cylindrical core is placed in a cylindrical cavity of a mold, and a molten resin material is injected and injected between the core and the inner peripheral surface of the cavity to form a pipe-shaped molded product. By pulling out the molded product from the cavity and removing the mold, when obtaining the pipe-shaped molded product from the cavity when obtaining a photosensitive drum base made of a synthetic resin, the outer peripheral surface of the molded product 3. A method for producing a photosensitive drum substrate according to claim 1 or 2, wherein minute stripe-like irregularities are formed along the axial direction to obtain the photosensitive drum substrate according to claim 1 or 2.