JP3250962B2 - Photoconductor and image forming apparatus - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a photosensitive member having a photosensitive layer of amorphous silicon, and an image forming apparatus equipped with the photosensitive member of the present invention.

[0002]

2. Description of the Related Art A photosensitive member having a photosensitive layer made of amorphous silicon (hereinafter, amorphous silicon is abbreviated as a-Si) has already been commercialized, and this a-Si photosensitive member has a drum shape made of aluminum metal. The outer peripheral surface of the substrate is mirror-finished with a surface roughness of about 0.1 S by cutting or the like, and then the a-Si photosensitive layer is formed to a thickness of 10 μm to 50 μm by CVD or PVD and further thickened to about 80 μm. Obtained by forming.

By performing mirror finishing before forming a film on a drum-shaped substrate as described above, the surface of a photosensitive layer formed and formed on the substrate is made as smooth as possible and the number of defects is suppressed as much as possible. Has been improved.

However, a laser beam printer (LB)
With respect to the Al metal substrate for P), it has been proposed that the outer peripheral surface is positively roughened so that the laser beam incident on the photosensitive layer is irregularly reflected on the substrate so that interference fringes do not occur. (See Japanese Patent Publication No. Hei 2-59981).

The electrophotographic process for the a-Si photoreceptor includes the Carlson method and the like. Generally, the process employs a cleaning means for removing residual toner on the surface of the photoreceptor. This cleaning means includes a blade method, a fur brush method, a magnet brush method, and the like. Regardless of which method is used, the toner is used to immediately remove the residual toner attached to the surface of the photosensitive layer. Is preferable from the viewpoint of good cleaning.

[0006]

However, even in such an image forming apparatus equipped with an a-Si photoreceptor, if the image forming apparatus has been operated for a long time at normal temperature and low humidity, or in a conventional image forming apparatus, the average particle size is small. In contrast, when a toner having an average particle diameter smaller than that is used in order to obtain a high quality image,
It becomes easy to adhere or fuse to the surface of the Si photoreceptor, so that it is difficult to remove the toner in the cleaning process, and as a result, there is a problem that a black spot-like image defect occurs in a white background image.

In view of the above circumstances, the present inventors have made intensive studies, and as a result, in order to prevent toner adhesion and fusing especially during cleaning, the surface of the photosensitive layer is not smoothed as in the prior art. On the contrary, it has been found that the problem can be solved by appropriately roughening the surface.

Accordingly, the present invention has been completed based on the above findings, and an object of the present invention is to provide a photoreceptor and an image forming apparatus which achieve good image formation by preventing toner adhesion and fusion during cleaning. It is in.

Another object of the present invention is to provide an image forming apparatus capable of obtaining a high-quality image even when operated for a long time at normal temperature and low humidity, or when a toner having an average particle diameter of less than 10 μm is used. It is in.

[0010]

The photosensitive member of the present invention has a photosensitive layer made of a-Si laminated on the outer peripheral surface of a drum-shaped substrate cut in the circumferential direction, and the surface of the photosensitive layer is made of amorphous silicon carbide (hereinafter, referred to as amorphous silicon carbide). , Amorphous silicon carbide is abbreviated as a-SiC), and a plurality of linear grooves having a triangular cross section are formed continuously on the surface of the photosensitive layer in the circumferential direction. The angle forming the top of the triangle is 140-177 °, the angle forming the bottom between adjacent triangles is 140-177 °,
Further, the pitch of each linear groove is set to 20 to 120 μm.

Further, the image forming apparatus of the present invention comprises the above-mentioned photoreceptor of the present invention, a charging means for applying a charge to the surface of the photoreceptor, and an exposing means for irradiating the charged area of the photoreceptor with light. The charging means and the exposure means form an electrostatic latent image on the surface of the photoreceptor, and a developing means for forming a toner image corresponding to the electrostatic latent image on the surface of the photoreceptor; The image forming apparatus further includes a transfer unit that transfers the toner to the transfer material, a cleaning unit that removes residual toner on the surface of the photoconductor after the transfer, and a charge removing unit that removes a residual electrostatic latent image after the transfer.

According to another image forming apparatus of the present invention, in the above-described image forming apparatus of the present invention, the average particle diameter of the toner used for forming the toner image is 10 μm or less.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Structure of Photoreceptor FIG. 1 is a layered structure of a photoreceptor 1 according to an embodiment of the present invention, and FIG.

First, in FIG. 1, a photosensitive layer 3 made of a-Si is formed on the outer peripheral surface of a conductive drum-shaped substrate 2 by a vacuum evaporation method.
A film is formed by an active reaction deposition method, an ion plating method, an RF sputtering method, a DC sputtering method, an RF magnetron sputtering method, a DC magnetron sputtering method, a thermal CVD method, a plasma CVD method, or the like. The photosensitive layer 3 is formed by sequentially laminating a carrier injection blocking layer 4, a photoconductive layer 5, and a surface protective layer 6, for example.

The substrate 2 includes copper, brass, SUS, Al,
Examples include a metal conductor such as Ni, or an insulator such as glass or ceramic whose surface is coated with a conductive thin film. The substrate 2 may be a sheet-shaped, belt-shaped or web-shaped flexible conductive sheet.
Transparent conductive materials such as metals such as Al, Ni or tin oxide, indium tin oxide (ITO) or the like on a metal sheet such as US, Al, Ni, or a polymer resin film such as polyester, nylon, or polyimide; An organic conductive material coated by vapor deposition or the like and subjected to a conductive treatment is used.

As shown in FIG. 2, on the surface of the photosensitive layer 3 (surface protective layer 6), a linear groove M having a triangular cross section is formed in the circumferential direction of the drum. In the present invention, the triangular top is formed. The angle a forming the (peak) e is 140 to 177 °, preferably 160 to 175 °, and the angle b forming the bottom (valley) d between adjacent triangles is 140 to 177 °, preferably 160. To 175, the pitch P of each linear groove M is 20 to 12
The thickness is set to 0 μm, preferably 40 to 100 μm.

That is, in the case of a conventional photoreceptor, the substrate surface is mirror-finished with a surface roughness of about 0.1 S, so that the surface of the photosensitive layer has the same surface roughness. According to the photoreceptor 1 of the present invention, by roughening the surface of the photosensitive layer 3 as described above, a good image as before can be obtained, and toner adhesion / fusion at the time of cleaning can be prevented.

When the angle a forming the top portion e is less than 140 °, and when the angle b forming the bottom portion d is less than 140 °, toner adhesion to the surface of the photoconductor becomes remarkable in a 500,000 sheet running test. appear.

On the other hand, when the angle a forming the top part e exceeds 177 °, the angle b forming the bottom part d exceeds 177 °, and when the pitch P of the linear grooves M is less than 20 μm or more than 120 μm. , Aluminum (Al)
It becomes difficult to cut a metal pipe such as a metal pipe, and scratches and burrs are generated on the surface of the metal pipe.

The tapered surfaces C1 and C2 are formed as shown in FIG. 2 by forming the linear grooves M having a triangular cross section. However, the widths (intervals) of both of them are not required to be the same. The same effect can be obtained. Furthermore, the top part e and the bottom part d may be slightly rounded.

The surface shape as described above is the same as that of the drum-shaped substrate 2.
The cutting conditions are determined by the circumferential cutting conditions, such as the material and type of the cutting tool, and the number of revolutions and feed speed during cutting. In the present invention, various experiments are repeated to find out the optimal cutting tool and cutting conditions.

Configuration of Image Forming Apparatus FIG. 3 shows an image forming apparatus 7 of a printer configuration equipped with the photoreceptor of the present invention. Reference numeral 8 denotes a photoreceptor. Device 9 and an exposure device 10 (LED head) as an exposure means for irradiating light after charging.
A developing device 12 having a toner 11 for forming a toner image on the surface of the photoreceptor 8, and a transfer device 14 serving as a transfer device for transferring the toner image to a transfer material 13.
And a cleaning means 15 for removing the residual toner on the surface of the photoreceptor after the transfer, and a charge removing means 16 for removing the residual electrostatic latent image after the transfer. Also, 1
Reference numeral 7 denotes a fixing device for fixing the toner image transferred to the transfer material 13 by heat or pressure.

In the Carlson method, the following processes are repeated. The peripheral surface of the photoconductor 8 is charged by the corona charger 9. By exposing the image with the exposure device 10, an electrostatic latent image as a potential contrast is formed on the surface of the photoconductor 8. This electrostatic latent image is developed by the developing machine 12. By this development, the black toner adheres to the surface of the photoreceptor by electrostatic attraction with the electrostatic latent image and is visualized. The toner image on the surface of the photoreceptor is electrostatically transferred from the back surface of the transfer material 13 such as paper by applying an electric field having a polarity opposite to that of the toner, whereby an image is obtained on the transfer material 13. The cleaning unit 15 mechanically removes residual toner on the surface of the photoconductor. The entire surface of the photoconductor is exposed to intense light, and the remaining electrostatic latent image is removed by the charge removing means 16.

The image forming apparatus 7 has a printer configuration. However, if an optical system such as a lens or a mirror that transmits reflected light from a document is used in place of the exposure unit 10, the image forming apparatus 7 has a configuration similar to that of a copier. Become.

The image forming apparatus 7 employs ordinary dry development, but is also applicable to liquid developers used for wet development. Incidentally, the average particle size of the pigment of this liquid developer is extremely small, about 1 μm.

Thus, according to the image forming apparatus 7 of the present invention, when the average particle diameter is 10 to 20 μm as in the related art, even if the image forming apparatus 7 is operated for a long time at normal temperature and low humidity, the toner a -No adhesion or fusion to the surface of the Si photoreceptor. Further, even when a toner having an average particle diameter of less than 10 μm was used to obtain a high quality image, the toner did not adhere or fuse to the surface of the a-Si photoconductor.

[0027]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS In producing a drum-shaped substrate 2, a raw tube made of Al having a purity of 99.9% was prepared, and its surface was deliberately formed into a mountain-valley shape by cutting with a natural diamond bite. Was made into a continuous triangular wave shape, but various linear grooves M were provided by changing the mounting angle of the cutting tool used and the shape of the cutting edge of the cutting tool. Further, the pitch P of the linear grooves M was varied in various ways by changing the number of revolutions and the feed rate during substrate cutting.

Then, a photosensitive layer 3 is formed on the various drum-shaped substrates 2 by a plasma CVD method.
This photosensitive layer 3 contains 1500 ppm of boron and 1.0% of oxygen.
%, A-Si carrier injection blocking layer 4 containing 0.7% nitrogen, a-Si photoconductive layer 5 containing 0.5 ppm boron, a
And a surface protective layer 6 made of SiC.

According to this plasma CVD method, silane gas, methane gas, hydrogen gas, diborane gas, and nitrogen oxide gas are used as starting material gases, and various gases are appropriately introduced into the reaction vessel according to the formation of each layer. Subsequently, each layer is sequentially provided by generating plasma at a high voltage.

Thus, as shown in Table 1, various photoreceptors (Sample Nos. A to L) were prepared by forming a number of linear grooves M in the circumferential direction. However, the sample No. A is a conventional one in which the surface of the photosensitive layer is smooth and Rmax is about 0.1 μm.

With respect to the angle a of the top part e and the angle b of the bottom part d, a cross-sectional curve is drawn in the direction of the center axis of the drum with respect to the surface of the photosensitive layer at X: Y = 1: 1 using a surface roughness meter. (That is, the measurement range of the X-axis and the Y-axis of the chart paper used in the surface roughness meter was made the same), and the cross-sectional curve was obtained by measuring with a protractor. Further, the pitch P was determined from the sectional curve.

[0032]

[Table 1]

Next, the various photoconductors are mounted on the image forming apparatus 7 (dry development: toner average particle diameter 8 μm), images are formed by the Carlson method, a 500,000 sheet running test is performed, and image characteristics and toner adhesion are measured. When the condition was measured, the results shown in Table 1 were obtained.

The evaluation of the image characteristics was performed by using the magnifying loupe.
It was determined by visually observing the entire surface of a three-size white background image and examining the presence or absence of image defects. Then, the evaluation was made with the mark “×” and the mark “X”. The mark “○” indicates that a good white background image was obtained, and the mark “X” indicates the case where a black dot-like or black streak-like image defect occurred in the white background image. Further, the degree of toner adhesion was measured by visually observing the surface of the photoreceptor while referring to the white background image, and confirming the number of toner adhering portions.

In the above embodiment, at room temperature and normal humidity (23 ± 3
The image forming apparatus 7 having an average toner particle size of 8 μm at 50 ° C., 50 ± 10%) was used. However, as an example, the average toner particle size at normal temperature and low humidity (23 ± 3 ° C., 15% or less) was 16 μm.
When the same experiment was performed using the m image forming apparatus 7, the same results were obtained for each sample in both the image characteristics and the degree of toner adhesion.

As is clear from the results shown in Table 1, the sample No. of the present invention. As for C, D, E, F, I, J, and K, a good image was obtained, and it was found that the adhesion of toner was completely eliminated or reduced to a small number.

[0037]

As described above, according to the photoreceptor and the image forming apparatus of the present invention, the surface of the photosensitive layer is made of a-SiC, and the surface of the photosensitive layer is formed with a triangular linear groove. Direction, the angle forming the top of the triangle is 140-177 °, the angle forming the bottom between adjacent triangles is 140-177 °, and the pitch of each linear groove is 20-120 μm. By doing so, good image formation can be obtained by preventing toner adhesion and fusion during cleaning, and even when the toner is operated for a long time at normal temperature and low humidity, or even when a toner having an average particle diameter of less than 10 μm is used. And good image formation was obtained.

According to the photoreceptor of the present invention, by setting the pitch of the linear groove to 20 to 120 μm as described above,
The substrate cutting conditions can be easily obtained, thereby improving manufacturing efficiency and manufacturing control, and as a result, manufacturing costs can be reduced.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a layer configuration of a photoreceptor according to an embodiment of the present invention.

FIG. 2 is an enlarged sectional view of a surface of a photoreceptor according to the embodiment of the present invention.

FIG. 3 is a schematic view of the image forming apparatus of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1, 8 Photoreceptor 2 Substrate 3 Photosensitive layer 5 Photoconductive layer 6 Surface protective layer 7 Image forming apparatus 9 Corona charger 10 Exposure device 11 Toner 12 Developing machine 13 Transfer receiving material 14 Transfer device 15 Cleaning means 16 Static elimination means M Groove e Top of linear groove a Angle forming top d Bottom of linear groove b Angle forming bottom P Pitch of linear groove

Continuation of the front page (56) References JP-A-60-263948 (JP, A) JP-A-2-59765 (JP, A) JP-A-64-86146 (JP, A) JP-A-8-160821 (JP) JP-A-8-137119 (JP, A) JP-A-3-116154 (JP, A) JP-A-2-173657 (JP, A) JP-A-5-181295 (JP, A) (58) Field surveyed (Int.Cl. ⁷ , DB name) G03G 5/08

Claims (3)

(57) [Claims] A photosensitive member comprising: a photosensitive layer made of amorphous silicon laminated on an outer peripheral surface of a drum-shaped substrate cut in a circumferential direction; and a surface of the photosensitive layer made of amorphous silicon carbide. A large number of linear grooves having a triangular cross section are continuously formed in the circumferential direction on the surface of the surface, and the angle forming the apex of the triangular shape is 140 to 17.
At 7 °, the angle forming the bottom between adjacent triangles is 140
~ 177 °, and the pitch of each linear groove is 20 ~ 120
A photoreceptor characterized by having a thickness of μm. 2. The photoconductor of claim 1, comprising: a charging unit for applying a charge to the surface of the photoconductor; and an exposure unit for irradiating a charged area of the photoconductor with light. Developing means for forming an electrostatic latent image on the surface of the photoreceptor and forming a toner image corresponding to the electrostatic latent image on the surface of the photoreceptor, and transfer means for transferring the toner image to a material to be transferred An image forming apparatus comprising: a cleaning unit that removes residual toner on the surface of the photoconductor after the transfer; and a static elimination unit that removes a residual electrostatic latent image after the transfer. 3. The image forming apparatus according to claim 2, wherein the toner used for forming the toner image has an average particle diameter of less than 10 μm.