JP3259554B2 - Cylindrical electrophotographic photoreceptor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in an electrophotographic photosensitive drum (hereinafter, referred to as a photosensitive drum) used for a method of pressing a member against the surface of a photosensitive member, such as a contact charging method and a cleaning method using a cleaning blade. .

[0002]

2. Description of the Related Art As a method for charging a photosensitive drum, a method using a corona charger is generally used, but this method has a drawback that ozone is generated. Therefore, recently, instead of the corona charging method, a contact charging method in which a charging member is brought into contact with a member to be charged to perform charging has been studied, and some of them have been put to practical use. The contact charging method uses a voltage (for example,
A charging member to which a DC voltage of about 2 KV and an AC voltage are applied) is brought into contact with the member to be charged with a predetermined pressing force to charge the member to a predetermined potential, and
2 of charging start voltage when DC voltage is applied to the charging member
By forming an AC voltage having a peak-to-peak voltage that is twice or more between the charging member and the charged body, the charged body can be uniformly charged, and the generation of ozone is also significantly greater than the corona charging method. Because of the reduction, there is an advantage that an additional means and a mechanism indispensable in the corona charging method are not required.

[0003]

However, the contact charging member used in the above-described contact charging method is applied to an image forming apparatus for forming an electrostatic latent image by line scanning on a photosensitive drum as a member to be charged, for example, a laser. When used as a charging unit of a beam printer, the contact charging member and the photosensitive drum are in contact with each other, so that an oscillating electric field formed between them vibrates them, thereby causing a vibration noise to be easily generated. There is. The generation of vibration noise is also a phenomenon that occurs when cleaning is performed by pressing the cleaning blade against the surface of the photoconductor. Such vibration noise increases as the thickness of the photosensitive drum decreases. As one of the solutions for preventing the generation of vibration noise, a method of filling a photosensitive drum with a filler has been proposed.

[0004] In the case of filling with a filling material, in particular, when the thickness is 1.
It is very effective for a photoreceptor drum of 5 mm or less, and as a filler, a metal material, a viscoelastic material (for example,
-105348), and those formed of a composite thereof. However, in the case of a metal material, there are problems such as lack of flexibility in processing and an increase in weight. In the case of a viscoelastic material, the dimensional accuracy of the cylindrical support is increased due to thermal expansion / contraction of the filler. In the case of these composites, there is a problem that the number of assembling steps is extra, and none of them is satisfactory. A method of attaching a sheet member to the inside of the photosensitive drum has also been proposed (for example, Japanese Patent Application Laid-Open No. 3-105348), but in this case, a satisfactory result cannot be obtained. The present invention solves the above-mentioned problems in the prior art, and in a thin-walled photosensitive drum, a photosensitive drum having a function of preventing vibration at the time of charging by a contact charging method or press-contact between a drum and a blade in blade cleaning. It is intended to provide.

[0005]

Means for Solving the Problems In order to achieve the above object, the present inventors have made intensive studies and found that vibration can be suppressed by the characteristics and shape of the filling material to be filled in the photosensitive drum. Thus, the present invention has been completed. That is, according to the present invention, by using a resin as the filling body in the photosensitive drum, a degree of freedom can be obtained in the processing of the filling body itself, and the kind of the resin is changed to a coefficient of linear expansion of aluminum of 2.3 × 10 ^−. By selecting within a certain range above and below ⁵ cm / cm / ° C, it can be used without impairing the dimensional accuracy of the cylindrical support due to thermal expansion / contraction after insertion of the filler. I found it. The electrophotographic optical member of the present invention has a linear expansion coefficient of 1.0 × 10 inside a cylindrical support made of an aluminum hollow pipe having a thickness of 1.5 mm or less.
^{-5 to} 5.0 × 10 ^-5 cm / cm / ° C. The resin filler is inserted.

In the present invention, the filler to be inserted into the cylindrical support has a cylindrical shape, and has a linear expansion coefficient of 1.0 × 10 ^{−5 to} 5.0 × 10 ^{−. 5} cm /
cm / ° C. When the coefficient of linear expansion is out of the above range, the dimensional accuracy of the cylindrical support is hindered by thermal expansion / contraction after the insertion of the filler, and abnormal noise is generated due to generation of vibration. Any resin can be used as the resin used for producing the filler to be used, as long as the resin satisfies the above linear expansion coefficient.
For example, nylon resin, ABS resin, polybutylene terephthalate (PBT resin), polyacetal (POM resin), and the like reinforced with a fiber material can be preferably used.

The filler used in the present invention may have a cylindrical shape as shown in FIG. 1 or one or more grooves formed on the surface as shown in FIG. Further, a hole as shown in FIG. 3 may be provided.
1 to 3, (a) is a crushed longitudinal sectional view, and (b) is a side view. In the present invention, the width of the groove is 2 to 10 mm, and the depth is 5 to 30 depending on the diameter of the drum.
mm and the number of grooves may be appropriately set in the range of 1 to 50 mm according to the length of the drum. The filler may be inserted at any position of the cylindrical support, but is preferably inserted at the center of the support. In addition, one filler may be inserted into the cylindrical support, but a plurality of fillers may be inserted.

[0008]

According to the present invention, while the linear expansion coefficient of an aluminum cylindrical support is 2.3 × 10 ⁻⁵ cm / cm / ° C., a resin filler inserted into the inside thereof is used. Has a linear expansion coefficient of 1.0 × 10 ^{−5 to} 5.0 × 10 ⁻⁵ cm / cm.
Since the range of / ° C., by adhering the resin filler in the interior of the cylindrical support, caused by a cleaning blade or a charging member, etc. in direct contact with the cylindrical photosensitive member vibration Energy is absorbed. As a result, the vibration is weakened, so that the vibration and the noise can be reduced. Therefore, as the filler to be inserted into the cylindrical support, the linear expansion coefficient is 1.0 × 10 ^{−5 to} 5.0 × 1.
If it is selected from the range of 0 ^-5 cm / cm / ° C, the dimensional accuracy of the cylindrical support on which the filler is inserted is controlled within the allowable range within the range from high temperature to low temperature in the actual use environment. It becomes possible to do.

[0009]

EXAMPLES The present invention will be described in more detail with reference to examples, but the present invention is not limited thereto. In addition,
“Parts” means “parts by weight”. Example 1 An aluminum pipe having an outer diameter of 40 mmφ × 318.5 mm × 1.25 mmt was prepared. Then, the following components were dispersed by a sand mill using 1 mmφ glass beads for 15 hours to prepare a dispersion, which was applied to the aluminum pipe, dried at 100 ° C. for 10 minutes, and dried to a coating film of 0.4 μm. A charge generation layer was formed. Vanadyl phthalocyanine 5 parts Polyvinyl butyral 5 parts (manufactured by Union Carbide: XYHL) n-butanol 300 parts

Next, a solution having the following composition was applied on the charge generation layer and dried at 100 ° C. for 30 minutes to form a coating film having a thickness of 20 μm.
m of the charge transport layer was formed. N, N'-diphenyl-N, N'-bis (3-methylphenyl)-[1,1'-biphenyl] -4,4'-diamine 40 parts Bisphenol A type polycarbonate resin 60 parts Methylene chloride 400 parts Fiber reinforced resin A (NT562 <Nylon type> manufactured by Otsuka Chemical Co., Ltd.) having an outer diameter of 37.5 mmφ and a length of 80 mm and having a cross-sectional shape shown in FIG. Part. The linear expansion coefficient of the fiber reinforced resin A is 2.3 × 10 ⁻⁵ cm / cm /
° C.

[0011] Thus an electrophotographic photosensitive drum thus obtained is inserted into the laser over printer <br/> over device for charging the charging roll method, at a distance of 10cm performing copying operation, start running / Sensory evaluation of noise at stop and during running was performed. Next, the electrophotographic photosensitive drum was mounted on an electrophotographic recording device in an environment of 40 ° C., and allowed to stand for 24 hours. Then, a copy operation was performed to evaluate image quality unevenness. further,
The electrophotographic photosensitive drum was removed from the electrophotographic photosensitive device and heated to 50 ° C. Thereafter, the outer diameter of the filler-filled portion and the unfilled portion was measured with a laser micrometer, A
Outer diameter of filled part and outer part of non-filled part of aluminum pipe
The difference from the diameter was determined .

Example 2 A photosensitive layer was formed on an aluminum pipe in the same manner as in Example 1. Next, outer diameter 37.5mmφ × length 80mm
FIG. 2 (where a = 3.5 mm, b = 17.5 mm,
(c = 2.5 mm, d = 2.0 mm) A fiber-reinforced resin A having a cross-sectional shape shown in the figure was molded by injection molding and inserted into the center of the inside of an aluminum pipe. At the time of insertion, insertion was possible at a lower pressure than in Example 1. Thereafter, evaluation of noise, outer diameter, and image quality unevenness at high temperature was performed in the same manner as in Example 1. Example 3 In the same manner as in Example 1, a photosensitive layer was formed on an aluminum pipe. Next, outer diameter 37.5mmφ × length 80mm
In FIG. 3 (a = 3.0 mm, b = 11.0 mm,
c = 2.5 mm, d = 2.5 mm, e = 10.5 mm,
(f = 2.0 mm) was formed by injection molding a fiber reinforced resin A having a cross-sectional shape shown in FIG. By providing the holes as shown in FIG. 3, the forming process was easy, especially when applied to a large-diameter drum. At the time of insertion, insertion was possible at a lower pressure than in the case of Example 1. Thereafter, evaluation of noise, outer diameter, and image quality unevenness at high temperature was performed in the same manner as in Example 1.

Example 4 A photosensitive layer was formed on an aluminum pipe in the same manner as in Practical Example 1. Next, outer diameter 37.5mmφ × length 80mm
The fiber reinforced resin B (OS-
30B <ABS type> manufactured by Otsuka Chemical Co., Ltd.) was injection-molded and inserted into the center of the inside of an aluminum pipe. In the same manner as in Example 1, the noise, the outer diameter, and the image quality unevenness at high temperature were evaluated. The linear expansion coefficient of the fiber reinforced resin B was 4.5 × 10 ⁻⁵ cm / cm / ° C. Example 5 In the same manner as in Example 1, a photosensitive layer was formed on an aluminum pipe. Next, outer diameter 37.5mmφ × length 80mm
The fiber reinforced resin C (BT2
62 <PBT type> manufactured by Otsuka Chemical Co., Ltd.) was molded by injection molding and inserted into the center of the inside of an aluminum pipe. In the same manner as in Example 1, the noise, the outer diameter, and the image quality unevenness at high temperature were evaluated. The linear expansion coefficient of the fiber reinforced resin C was 3.2 × 10 ⁻⁵ cm / cm / ° C. Example 6 A photosensitive layer was formed on an aluminum pipe in the same manner as in Example 1. Next, outer diameter 37.5mmφ × length 80mm
And a fiber reinforced resin D (AT3
42 <POM type> manufactured by Otsuka Chemical Co., Ltd.) was molded by injection molding and inserted into the center of the inside of an aluminum pipe. In the same manner as in Example 1, the noise, the outer diameter, and the image quality unevenness at high temperature were evaluated. The linear expansion coefficient of the fiber reinforced resin D was 3.8 × 10 ⁻⁵ cm / cm / ° C.

Comparative Example 1 In the same manner as in Example 1, a photosensitive layer was formed on an aluminum pipe. Next, outer diameter 37.5mmφ × length 80mm
The fiber reinforced resin E having the cross-sectional shape shown in FIG.
22B <ABS type> manufactured by Otsuka Chemical Co., Ltd.) was formed by injection molding and inserted into the center of the inside of an aluminum pipe. Evaluation of noise, outer diameter, and image quality unevenness at high temperature was performed in the same manner as in Practical Example 1. The linear expansion coefficient of the fiber reinforced resin E was 6.5 × 10 ⁻⁵ cm / cm / ° C. Comparative Example 2 A photosensitive layer was formed on an aluminum pipe in the same manner as in Example 1. Next, outer diameter 37.5mmφ × length 80mm
Then, a nylon resin (Zytel 101, manufactured by Dupont Japan Limited) having a cross-sectional shape shown in FIG. 1 was molded by injection molding and inserted into the center of the inside of an aluminum pipe. In the same manner as in Example 1, the noise, the outer diameter, and the image quality unevenness at high temperature were evaluated. The linear expansion coefficient of the nylon resin was 8.0 × 10 ⁻⁵ cm / cm / ° C.

Comparative Example 3 In the same manner as in Example 1, a photosensitive layer was formed on an aluminum pipe. Next, outer diameter 37.5mmφ × length 80mm
A POM resin (Duracon M90-44, manufactured by Polyplastics Co., Ltd.) having the cross-sectional shape shown in FIG. 1 was molded by injection molding and inserted into the center of the inside of an aluminum pipe. In the same manner as in Example 1, the noise, the outer diameter, and the image quality unevenness at high temperature were evaluated. Incidentally, the linear expansion Coefficient of the POM resin is met ^{10.0 × 10 -5 cm / cm /} ℃. Comparative Example 4 In the same manner as the actual Example 1 to form a photosensitive layer on the aluminum pipe. The noise, the outer diameter, and the image quality unevenness at high temperature were evaluated in the same manner as in Example 1. Example 1 above
6 and Comparative Examples 1-4 , noise, aluminum pie
The difference between the outer diameters of the unfilled portion of the filler-filled portion of the flop (Table 1
In referred to as "outer diameter difference"), and are summarized in Table 1 the results of evaluation of high-temperature uneven image quality.

[0016]

[Table 1] From these results, if the coefficient of linear expansion of the filler resin filled in the photosensitive drum is within the above range of the present invention, the noise sensory evaluation, the outer diameter of the filler filling portion of the aluminum pipe, and the like. It was found that both the difference from the outer diameter of the unfilled portion and the image quality unevenness due to copying at high temperature were within the practical range.

[0017]

According to the present invention, as described above, the resonance energy of the cylindrical support is absorbed in the electrophotographic recording apparatus, and the vibration thereof is reduced. As a result, the vibration can be reduced. The thermal expansion / contraction of the filler makes it possible to eliminate secondary obstacles that hinder the dimensional accuracy of the cylindrical support, which is extremely useful in industry.

[Brief description of the drawings]

FIG. 1 is a crushed longitudinal sectional view and a side view of an example of a packing used in the present invention.

FIG. 2 is a crushed longitudinal sectional view and a side view of another example of the packing used in the present invention.

FIG. 3 is a crushed longitudinal sectional view and a side view of still another example of the packing used in the present invention.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-5-34936 (JP, A) JP-A-3-105348 (JP, A) JP-A-6-95560 (JP, A) JP-A-5-95560 186668 (JP, A) JP-A-1-223467 (JP, A) JP-A-60-11851 (JP, A) JP-A-5-69768 (JP, U) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 5/00

Claims (1)

(57) [Claims] A linear expansion coefficient of 1.0 is provided inside a cylindrical support made of an aluminum hollow pipe having a thickness of 1.5 mm or less.
^{× 10 -5 ~5.0 × 10 -5 cm} / cm / ℃ electrophotographic photoreceptor, characterized in that it has inserted a packing made of a resin.