JPH10207291A - Electrophotographic photoreceptor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain an economical electrophotographic photoreceptor capable of stably guaranteeing printing quality over a longer period, with a long product' s life, at a low cost by making a grounding electrode plate made of phosphor bronze and allowing the circular-arcuate top end having a specific radius of curvature, of the ground electrode plate to contact with a stainless steel shaft body. SOLUTION: A ground plate 1 is provided with a triangular projected part on the circumference of a circle and when the ground plate 1 is inserted into an aluminum substrate 16, the projected part comes into contact with the inside of the aluminum substrate 16. When a ground bar 21 is inserted into a photoreceptor 10, a ground section 3 formed around the center hole of the ground plate 1 is pushed out. At this time, the ground section 3 is formed so that an angle θ formed by the pushed out ground section 3 and the ground plate 1 is 5 deg.-40 deg.. The top end of the ground section 3 is set so that the radius of curvature R of a contact coming into contact with the ground bar 21 is >=0.5mm. Since the ground plate 1 is of a thin plate made of the phosphor bronze and has spring elasticity, stable contact and proper pressing force can be applied to the ground bar 21 made of stainless steel.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylindrical electrophotographic photosensitive member used for electrophotographic process equipment,
In particular, the present invention relates to a structure of an electrode plate for grounding a photoconductor and its application equipment.

[0002]

2. Description of the Related Art In general, the surface of a cylindrical photosensitive member used in an electrophotographic process application device (hereinafter simply referred to as an application device) is charged due to the necessity in the electrophotographic process. Subsequently, when exposure, which is one of the electrophotographic processes, is performed,
Photocharge is generated in the photosensitive layer in the exposed area. Subsequently, a predetermined electrostatic latent image is formed on the corresponding photosensitive layer surface. In order to form the electrostatic latent image, it is necessary to move the photo-generated charges to the surface of the photosensitive layer and to move the charges of the opposite polarity to the substrate side for removal (earth). For this purpose, the photoreceptor is a conductive substrate made of aluminum alloy etc. and applied equipment (earth potential)
The center shaft body (earth rod) on the side is electrically conductively connected by a resin flange having a ground electrode plate (earth plate).

[0003]

On the other hand, the electrophotographic process executed in the above-mentioned application equipment involves the rotational driving of the photosensitive member. This rotation is often transmitted via a gear provided around the flange fitted to the end of the photoconductor. The central shaft (ground bar) on the application device side is formed of stainless steel, is inserted into the central shaft of the photoconductor, does not rotate, and has a function of supporting and positioning the photoconductor. As described above, in order to execute the electrophotographic process, the photoconductor and the ground bar are conductively connected by a ground plate. As a shape of a grounding plate for ensuring the grounding, there is a conventional one shown in the sectional view at the end of the photosensitive member of FIG. Therefore, the grounding is performed by bringing the conductive base (aluminum base) 16 of the photoreceptor into contact with the grounding rod 21 of the applied device by the grounding plate 12 having a shape as shown in the figure. However, as described above, when the photoconductor 15 rotates during use of the application equipment, the resin flange 13 fitted to the end of the photoconductor and the ground plate 12 also rotate, so that the ground around the non-rotating ground rod 21 is grounded. The plate 12 comes into contact while rotating. Since the hardness of the stainless steel of the grounding rod is greater than the hardness of the electrode plate, the contact 14 on the grounding plate side is very easily worn.

Conventionally, for example, the earth rod 21 is 8.5 m
Using a stainless steel rod of mΦ, a phosphor bronze plate as the ground plate 12, and 0.25 mm to
Using a flat plate having a thickness of 0.5 mm, a section is provided which contacts the aluminum base and the earth rod at a predetermined angle with respect to the inner end surface of the flange 13 with the fulcrum as a fulcrum. The tip of the section was a contact having a shape bent at 90 degrees. This way,
Although the initial contact is stable, there has been a problem that after long-term use, the contact portion is worn, a hole is formed, and the contact becomes unstable. As a countermeasure against hole opening, if the thickness of the ground plate is increased, the period until the hole is opened increases accordingly, but the flexibility of the ground plate as a spring is gradually lost. However, there is a problem that stable conductive connection cannot be maintained even if the value is increased, and stable printing characteristics cannot be obtained. There is also a disadvantage that the price is high.

Since the contact between the ground plate and the ground rod having the above-described shape is inevitably worn due to rotation, the contact of the ground plate having the above-described shape gradually becomes unstable.
It has been difficult to guarantee stable print quality over a long period of time. Problems have also determined this product life. The purpose of the present invention is to guarantee the print quality stably for a longer period of time,
An object of the present invention is to provide an inexpensive and economical electrophotographic photosensitive member having a long product life.

[0006]

According to the present invention, there is provided a cylindrical conductive substrate, a photosensitive layer formed on an outer surface thereof, and a resin fitted to an opening end of the substrate. In the electrophotographic photoreceptor comprising a ground electrode plate for electrically connecting the base and the stainless steel shaft on the electrophotographic process application device side,
The ground electrode plate is made of phosphor bronze, is provided with a convex portion that comes into contact with the base in the fitting portion, and is brought into contact with the stainless steel shaft at an arc-shaped tip having a radius of curvature of 0.5 mm or more. Is done.

Further, in the present invention, it is preferable that the ground electrode plate has a ground piece having a pressing force at an arc-shaped tip of 0.42 to 0.93 kgf. Further, in the present invention, in the electrophotographic photoreceptor, it is preferable that electrical connection between the base and the stainless steel shaft is made by a ground electrode plate including a plurality of pieces that come into contact with the stainless steel shaft. .

According to the present invention, in the electrophotographic photosensitive member, it is preferable that the plate thickness of the ground electrode plate is 0.1 to 0.25 mm. Further, according to the present invention, in the electrophotographic photosensitive member, an angle between a section of the ground electrode plate in contact with the stainless steel shaft and a surface perpendicular to the stainless steel shaft is 5 ° to 40 °. preferable.

[0009]

FIG. 1 shows an embodiment of the present invention. FIG. 1 is a cross-sectional view near one end of the photoconductor of the present invention. The flange 13 is fitted to one open end of the cylindrical aluminum base 16 and fixed by an adhesive (not shown). A gear 11 is formed around the exposed portion of the flange from the end of the aluminum base to transmit the rotational driving force of the electrophotographic application device to the photosensitive member. An earth plate 1 shown in FIG. 3 is fixed to the end face of this flange on the side to be inserted into the photoconductor. This earth plate 1 has a triangular convex portion provided around a circular shape.
When inserted into 6, the projection comes into contact with the inner surface of the aluminum base. In the center of the flange 13 and the ground plate 1, there is provided a central hole into which a central shaft (ground rod) for positioning and holding the photosensitive member in an electrophotographic application device and for connecting to a ground potential is inserted. I have. When the earth rod is inserted into the photoconductor, the earth piece 3 formed around the center hole of the earth plate 1 is pushed out. The ground piece 3 is formed around the center hole of the ground plate 1 so that the angle formed between the ground piece 3 and the ground plate 1 extruded at this time is a predetermined angle. Further, the tip of the ground piece 3 has a contact 14 which is in contact with the ground rod 21 and has a predetermined curvature R. Since the ground plate 1 is a thin plate of phosphor bronze and has spring elasticity, it can apply a stable contact and an appropriate pressing force to the ground rod 21 made of stainless steel. By using an earth plate 1 made of phosphor bronze having a predetermined thickness and changing the angle between the earth piece and the earth plate 1 variously, the earth piece 3 at the contact 14 can be obtained.
Of the contact 14 at the tip of the ground piece and various changes in the curvature R of the contact 14 at the tip of the ground piece were examined for the relationship between the durability of the contact 14 and the printing stability.

First, the angle between the earth piece 3 formed when the earth rod 21 is inserted into the earth plate 1 having a thickness of 0.1 mm and the earth plate 1 is 0 °, 60 °, 0 °, 5 °,
8 degrees of 10, 20, 30, 40, 50, 60 degrees
When the pressing force at the contact 14 was measured for each type, 1.0 kgf, 0.9 kgf, 0.9
3kgf, 0.85kgf, 0.73kgf, 0.62
kgf, 0.55kgf, 0.42kgf, 0.30k
A gf pressing force was measured.

For the above eight kinds of pressing forces, the curvature R of the contact 14 is set to 0.5 mm, 1.0 mm, 2.0 mm, and 3.0 m.
m, 4.0 mm, and 5.0 mm, the distance in which the contact 14 comes into contact with the ground bar until the hole is opened is expressed as a wear limit distance in km, and the printing stability until the wear limit is reached. Good is represented by ○, and bad is represented by ×. The results of each measurement are shown in Table 1 below.

[0012]

[Table 1] A conventional photoreceptor having the shape of a ground plate and a ground piece was measured and evaluated in the same manner as in the present invention. Ground plate 1
Assuming that the thickness of the sheet No. 2 was 0.1 mm, eight kinds of earth section angles were prepared in the same manner as in Table 1, and the wear limit distance km and printing stability were measured. The results are shown in Table 2 below.

[0013]

[Table 2] Tables 1 and 2 show the following. The larger the angle of the section, that is, the smaller the pressing force, the longer the wear limit distance. As the curvature R (mm) of the contact increases, the wear limit distance increases. The printing stability tends to deteriorate if the pressing force is too small or too large. When the curvature R of the contact increases, the range of the pressing force for good printing stability increases. From Table 2, it can be seen that the right angle contacts have a thickness of 0.
At 1 mm, the wear limit distance is not only shorter than in the examples, but also the printing stability is poor even up to the wear limit. When the curvature R of the contact point is 0.5 mm or more, there is a range of the pressing force indicating good printing stability. The optimum range of the pressing force varies depending on the curvature R of the contact.

Although the printing stability deteriorates when a hole is formed in the contact point of the ground piece, that is, when the distance exceeds the wear limit distance,
X indicates the evaluation before the wear limit. ○ means that printing is stable until the wear limit distance is reached. The above printing stability is not good when the pressing force is small because the contact is unstable, and when the pressing force is large, it is not good because the contact state causes unstable state such as jumping. I found it.

Following the results in Tables 1 and 2, the plate thickness was set to 0.
When the evaluation was made in the same manner as in the case where the thickness was changed to 25 mm, it was found that the curvature R of the tip of the ground piece was 0.5 mm or more, as in Table 1, and the printing stability was good. However, the plate thickness is 0.25mm
Above, good printing stability could not be obtained probably because the pressing force was too large. 0.25mm thickness of conventional ground section
Then, the wear limit distance became longer, but the printing stability was not improved. It has also become expensive.

[0016]

As described above, according to the present invention, a cylindrical conductive substrate, a photosensitive layer formed on the outer surface thereof,
A resin flange fitted to the opening end of the base;
The resin flange is an electrophotographic photosensitive member including a ground electrode plate for electrically connecting the substrate and a stainless steel shaft on the side of the electrophotographic process application device, wherein the ground electrode plate is phosphor bronze; The base has a convex portion that contacts the inside of the fitting portion, and the stainless steel shaft has a contact that contacts the arc-shaped tip having a radius of curvature of 0.5 mm or more. The present invention can provide an inexpensive and economical electrophotographic photoreceptor that has a long life and a stable product life.

[Brief description of the drawings]

FIG. 1 is a partial cross-sectional view of an electrophotographic photosensitive member according to an embodiment of the present invention.

FIG. 2 is a front view of a ground plate used in the electrophotographic photosensitive member according to the embodiment of the present invention.

FIG. 3 is a partial cross-sectional view of an electrophotographic photosensitive member according to a conventional example.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ground plate 3 Ground piece 10 Photoconductor 13 Flange 14 Contact 16 Aluminum base 21 Ground rod

Claims (5)

[Claims] A cylindrical conductive base, a photosensitive layer formed on an outer surface of the base, and a resin flange fitted to an opening end of the base. In an electrophotographic photoreceptor including a ground electrode plate for electrically connecting a stainless steel shaft on the device side, the ground electrode plate is made of phosphor bronze, and comes into contact with the base in the fitting portion. An electrophotographic photoreceptor comprising a convex portion and a contact point in contact with the stainless steel shaft at an arc-shaped tip having a radius of curvature of 0.5 mm or more. 2. An electrophotographic photoreceptor according to claim 1, wherein said ground electrode plate has a ground piece having a pressing force of 0.42 to 0.93 kgf at its arc-shaped tip. 3. The stainless steel shaft body is electrically connected to the base by a ground electrode plate provided with a plurality of ground pieces in contact with the stainless steel shaft body. Electrophotographic photoreceptor. 4. The ground electrode plate has a thickness of 0.1 to 0.25.
The electrophotographic photosensitive member according to claim 3, wherein 5. An angle between a section of said ground electrode plate in contact with said stainless steel shaft and a plane perpendicular to said stainless steel shaft is 5 ° to 40 °. The electrophotographic photosensitive member according to the above.