JPS62295064A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To form a high-quality initial image and to enhance stability against the lapse of time and printing resistance by forming a photoconductive layer composed essentially of amorphous silicon, and the second surface layer containing nitrogen higher in concentration than N contained in the first surface layer. CONSTITUTION:The photoconductive layer 3 is formed on an electric charge injection blocking layer 2 formed on a substrate 1, the layer 3 is composed essentially of amorphous silicon containing elements of group III of the periodic table in the range of 0.1-100ppm, and the layer 3, preferably, has a film thickness of 1-100mum. The first surface layer 4 and the second surface layer 5 are composed essentially of amorphous silicon containing nitrogen in a concentration higher in the layer 5 than in the layer 4. It is preferred to control the nitrogen concentration of the layer 4 in the range of 10-100atom% of Si, and its film thickness in the range of 0.01-5mum. On the other hand, it is preferred to control the nitrogen concentration of the layer 5 in the range of 50-130atom% of Si, and its film thickness in the range of 0.01-5mum.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention Field of Industrial Application The present invention relates to an electrophotographic photoreceptor containing amorphous silicon.

Conventional Technology It is known that the lifespan of electrophotographic photoreceptors is mainly controlled by factors such as deterioration in electrical life, occurrence of scratches on the surface, and deterioration of the photoreceptor material itself (especially thermal changes). ing. In recent years, photoreceptors using materials mainly composed of amorphous silicon have been attracting attention because these materials have the potential to fundamentally eliminate the above-mentioned lifespan factors of conventional photoreceptors. It is. That is, the amorphous silicon material has stable repeatability in terms of electrical properties, high hardness and thermal stability, and has the potential to provide a photoreceptor with an extremely long life.

In addition, amorphous silicon not only holds promise for Nagano Life, but also exhibits high photosensitivity up to long wavelengths compared to conventional photoreceptor materials, and with appropriate formulations, the sensitivity can be extended to even longer wavelengths. It can also be extended. Therefore, it can also be applied to printers that use a small and low-cost semiconductor laser as a light source.

Problems to be Solved by the Invention Although amorphous silicon has great potential as a material for photoreceptors, in reality it has low resistance, 118 resistance, photosensitivity at long wavelengths, mechanical strength (especially ductility). ), stability over time, and image quality (temperature,
There are problems with humidity) dependence.

Amorphous silicon materials do have a high hardness, with a Wickers hardness of the order of 1000, but they do not come into contact with materials of lower hardness (for example, the edge of copy paper or the cleaning blade in a copy machine). As a result, there is a problem in that the contact portion exhibits image omission.

In general, when an amorphous silicon photoreceptor is used repeatedly in a copying machine (or printer) for a relatively long period of time,
This is known to cause a decrease in resolution (image deletion). The cause of this is thought to be the attachment of foreign matter to the surface of the photoreceptor and/or deterioration of the photoreceptor itself.

Roughly speaking, the image flow phenomenon occurs not only due to the adhesion of foreign matter to the photoconductor or deterioration of its quality, but also due to structural reasons of the photoconductor (for example, the use of an inappropriate surface layer), but in this case, Image deletion occurs at the initial stage, that is, within about a few cycles to vll0 cycles.

The present invention attempts to solve the problems of the amorphous silicon photoreceptor described above.

That is, an object of the present invention is to provide a high-quality initial image,
Another object of the present invention is to provide an electrophotographic photoreceptor having excellent stability over time and resistance to scraping.

Another object of the present invention is to provide an electrophotographic photoreceptor with high dark resistance and excellent charging ability.

Another object of the present invention is to provide an electrophotographic photoreceptor having high photosensitivity over the entire visible light range.

Another object of the present invention is to provide a photoreceptor whose characteristics are less dependent on the environment in which it is used.

Another object of the present invention is to provide an electrophotographic photoreceptor that provides stable and high-quality initial image acquisition in all usage environments and that does not deteriorate even after repeated use.

Means for Solving the Problems The above aspects of the present invention can be achieved by the following electrophotographic photoreceptor. That is, the electrophotographic photoreceptor of the present invention is formed by sequentially laminating a photoconductive layer, a first surface layer, and a second surface layer on a support, and the photoconductive layer is amorphous. The first surface layer and the second surface layer are each mainly made of amorphous silicon to which nitrogen atoms are added, and the nitrogen atom concentration in the second surface layer is the same as that of the first surface layer. The nitrogen atom concentration is higher than that in the surface layer of Further, the object of the present invention can be more effectively achieved by adding 0.11-1O0DD of group (I) atoms to the photoconductive layer of the photoreceptor. Also, between the support and the photoconductive layer, 100-5000p
By providing a charge injection blocking layer made of amorphous silicon doped with D group I atoms or V group atoms, the effects of the present invention are further enhanced.

Hereinafter, the electrophotographic photoreceptor of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a schematic diagram illustrating a typical structure of the electrophotographic photoreceptor of the present invention. In the figure, 1 is a support, 2 is a charge injection blocking layer, 3 is a photoconductive layer, and 4 and 5 are a first surface layer 1 and a second surface layer, respectively. The charge injection J1 layer of No. 2 is amorphous silicon doped with 110-5000 pp of H'A or Group V 137 atoms.

A more desirable amount of additive is in the range of 50-1 oooppm. Photoconductive layer No. 3 is amorphous silicon doped with 0.11-100 ppm of Group I atoms. A more desirable amount of additive is in the range of 0.55-5 opp. The surface layers 4 and 5 are made of amorphous silicon doped with nitrogen atoms, and the nitrogen atom concentration in the second surface layer 5 is necessarily higher than that in the first surface layer 4.

The support 1 can be appropriately selected depending on the purpose, such as metals such as aluminum, nickel, chromium, and stainless steel, or plastic sheets with conductive films, glass, and paper.

Each of the layers 2 to 5 above is a layer mainly composed of amorphous silicon, and can be formed by a glow discharge decomposition method, a sputtering method, an ion blasting method, a vacuum evaporation method, or the like. Taking glow discharge decomposition as an example, the manufacturing method is as follows. First, as the raw material gas, a mixture of a main raw material gas containing silicon atoms and a raw material gas containing necessary additive atoms is used. In this case, if necessary, a carrier gas such as hydrogen gas or an inert gas may be mixed into this mixture. Taking AC discharge as an example, the film forming conditions are: frequency 50Hz-5GH2, reactor internal pressure 10'-5 Torr, discharge power 1O-2000W.
, and the support temperature is 30-300°C. The thickness of each layer can be appropriately set by adjusting the discharge time. The main raw material gases containing silicon atoms include silanes, especially SiH4 and/or S! 2H6 is used.

The charge injection blocking layer 2 is made of amorphous 71 silicon doped with a group Ⅰ element or a group V element. The amount of additives is 110
-5000DD range is preferred.

Further, the film thickness is preferably in the range of 0.01-5 μm.

Whether a Group 1 element or a Group V element is used as an additive is determined by the charge sign of the photoreceptor.

For layer formation, diborane (82H6) is typically used as the raw material waste containing Group I elements, and phosphine (PH3>) is typically used as the raw material waste containing Group V elements.
is used. In addition to the Group I or Group V elements, a relaxation element can be added to this charge injection blocking layer mainly composed of amorphous silicon for various purposes.

The photoconductive layer 3 is made of amorphous silicon doped with m-group atoms in the range of 0.11-100Dp. Film thickness is 1-100
A range of μm is desirable. , Diporan is typically used as the raw material waste containing Group (I) atoms. In addition to Group I atoms, other elements can also be added to this photoconductive diagram, which is mainly composed of amorphous silicon, for various purposes.

Further, this photoconductive layer may be composed of two layers: a charge generation layer and a charge transport layer.

The surface layers 4 and 5 are mainly composed of amorphous silicon doped with nitrogen atoms. In layer formation, any raw material gas containing nitrogen atoms can be used as long as it is a single substance or compound that has nitrogen atoms as a constituent and can be used in a gas phase. NH3, N
2 Hydrogenated nitrogen compound gases such as H4 and HN3 can be mentioned. The nitrogen atom-containing raw material scraps used on the first and second surfaces, awns 4 and 5, may be the same or different. However, the nitrogen concentration in the second surface layer 5 must be higher than the degree of opening of nitrogen atoms in the first surface layer 4. In addition to nitrogen atoms, other elements can also be added to the first and second surface layers 4 and 5, which are mainly composed of amorphous silicon, for various purposes.

The nitrogen atom concentration in the first surface layer 4 is preferably in the range of 0.1 to 71.0 as an atomic ratio to silicon atoms. Further, it is desirable that the film thickness is in the range of 0.01=5μ7n.

The nitrogen atom concentration in the second surface layer 5 is preferably in the range of 0.5-1.3 as an atomic ratio to silicon atoms. Further, it is desirable that the film thickness is in the range of 0.01-5 μm.

The electrophotographic photoreceptor of the present invention can be used in any electrophotographic process, especially in an electrophotographic process in which at least the surface of the photoreceptor is heated to 35 to 50 inches. can be used more advantageously.This is because when used with the photoreceptor surface heated to the above range, a stable and high-quality initial image can be obtained under any usage environment, and it can be used repeatedly. This is because image quality does not deteriorate even when the image quality is changed.

Such an electrophotographic process will be explained with reference to FIG.

FIG. 2 shows a schematic configuration of an electrophotographic apparatus using the electrophotographic photoreceptor of the present invention, 6 is the electrophotographic photoreceptor of the present invention, and 7 is the photoreceptor in a dark place. Charging means for uniformly charging; 8 is a latent image forming means for exposing a photoreceptor to a light image corresponding to the original image to form a latent image; 9 is for making the latent image visible with toner powder; developing means, 10 is a transfer means for transferring the developed image onto a transfer member, 1
1 is a fixing means for fixing the transferred image, 12 is a cleaning means, 13 is a transfer paper, 14 is a photoreceptor heating means,
A quartz lamp is installed in the rotating shaft.

The means for heating the photoreceptor can be provided at any position. In FIG. 2, the photoreceptor heating means 14 is provided inside the rotation shaft for rotating the photoreceptor, but in addition, the photoreceptor heating means 14 is provided on the circumferential surface of the photoreceptor as well as the developing means, charging means, transfer means, etc. It may be provided at an appropriate position. Further, it is possible to provide it not only on the photoreceptor layer side but also on the support body side. When provided on the support side, the position can be set arbitrarily, but for example, a planar heater that uniformly contacts the photoreceptor support side and heats the photoreceptor is preferable.

As a means for heating the photoreceptor, a heating lamp such as a quartz lamp (quartz lamp) in which a nichrome wire is disposed in a quartz glass, a sheet heater in which a nichrome wire is disposed in a heat-resistant flexible rubber such as silicone rubber, etc. In addition, a hot air blower type heater, a heater, a heater that uses radiant heat such as infrared rays, a heater that uses heat from a fixing section, etc. are also applicable. Any means can be used to supply electricity to the photoreceptor heating means, but especially when the heating means is provided inside the photoreceptor support, the photoreceptor rotates, so the 'slip ring' It is preferable to use one that conducts electricity through the .

EXAMPLES Hereinafter, the present invention will be specifically explained using examples and comparative examples.

Silane (SiH4) was
A charge injection blocking layer having a thickness of about 0.5 μm was produced on a cylindrical aluminum support by glow discharge decomposition of a mixture of gas, hydrogen (H2) gas, and diborane (82H6) gas. The manufacturing conditions at this time were as follows.

100% silane gas flow rate: 100cm3/min,
100 p p m * Prime diluted diborane gas flow "jL
: 200Cyj3/m'+ sleep reactor internal pressure: 0
．． 5 rorr, discharge type crab 100W.

Discharge time: 30m1n.

Discharge frequency fi: 13.56 MH2, support: crystal temperature: 250°C0 (described below) In the following examples and comparative examples,
The discharge frequency and support temperature under the manufacturing conditions of each layer are as follows:
Fixed to the above value. ) After the charge injection blocking layer is formed, the inside of the reactor is sufficiently evacuated,
Next, a mixture of silane gas, hydrogen gas, and diborane gas was introduced and decomposed by glow discharge to form a photoconductive layer having a thickness of about 20 μm on the charge injection blocking layer. The manufacturing conditions at this time were as follows.

100% silane gas flow m: 200CH3/mi Hydrogen gas flow fji: 1800m3/mi
n.

1ooppm hydrogen diluted diporan gas flowffi: 20
cm3/1in, reactor internal pressure: 1.5 Torr
.

Discharge type crab 300W, discharge time: 240 m1n0 After the photoconductive layer is formed, the inside of the reactor is sufficiently evacuated, and then a mixture of silane gas, hydrogen gas, and ammonia (NH3) gas is introduced to perform glow discharge decomposition. This produced a first surface layer on the photoconductive layer having a thickness of approximately 0.3 μ7. The manufacturing conditions at this time were as follows.

100% silane gas flow rate: 30 to 1B3/mi hydrogen gas flow rate: 2000m3/min, 1
00% ammonia gas flow m: 30 cm3/mi
n, reactor internal pressure: 0.5 Torr.

Discharge box crab 50W, discharge time: 6omin0 When the composition of this surface layer was analyzed, the atomic ratio of nitrogen atoms to silicon atoms was about 0.6.

After the formation of the first surface layer, the inside of the reactor is sufficiently evacuated, and then a mixture of silane gas, hydrogen gas, and ammonia gas is introduced for glow discharge decomposition, so that about 0% A second surface layer was produced with a thickness of .1 μm. The manufacturing conditions at this time were as follows.

100% silane gas flow%: 17 cm3/min
.

100% hydrogen waste flow fii-: 2000m3/mi
n.

ioo% Ammonia gas flow Li: 43 cm3/
min.

Reactor internal pressure: 0.5 Torr.

Discharge box crab 50-1 Discharge time: 20m1n.

When the composition of this surface layer was analyzed, the atomic ratio of nitrogen atoms to silicon atoms was approximately 0.8.

The electrophotographic photoreceptor having the charge injection blocking layer, the photoconductive layer, the first surface layer, and the second surface layer on the aluminum support obtained as described above was subjected to image quality evaluation in a copying machine. went. The setting environment of the copying machine is 30℃/85%RH120
Three types were used: 150% RH at 10° C. and 15% RH at 10° C./15% RH. (Hereinafter, these three types of environments will be collectively referred to as the three environments.

) Furthermore, the drum heating device in the copying machine was operated so that the drum surface was at about 45°C.

The photoreceptor whose surface was heated formed clear images in three environments at the initial stage. After the initial image quality evaluation, we conducted a copying test of approximately 20,000 sheets in an environment of 20°C and 150% RH, and then changed the installation environment of the copying machine and evaluated the image quality. Image obtained.

Roughly, the copies obtained in this evaluation test were
After 0,000 copies were made, high image density with no fog was observed in any environment, and no image quality defects due to scratches on the surface of the photoreceptor were observed.

Comparative Example 1 A charge injection blocking layer and a photoconductive layer were sequentially formed on an aluminum support using the same apparatus, the same conditions, and the same method as in Example.

After forming the photoconductive layer, the inside of the reactor is sufficiently evacuated, and then a mixture of silane gas, hydrogen gas, and ammonia gas is introduced and decomposed by glow discharge to form a film with a thickness of approximately 0.3 μm on the photoconductive layer. A surface layer with . The manufacturing conditions at this time were as follows.

100% silane gas flow rate: 17 cm3/mi 1
00% hydrogen sludge flow fi: 2000m3/min.

ioo% ammonia gas flow ta: 43 cm3/
min.

Reactor internal pressure: 0.5 Torr.

Discharge box crab 50W, discharge time: 60m1n0 When the composition of this surface layer was analyzed, the atomic ratio of nitrogen atoms to silicon atoms was about 0.8.

When a photoreceptor having a charge injection blocking layer, a photoconductive layer, and a surface layer manufactured on an aluminum support as described above was evaluated in a copying machine, it was found that severe image blurring occurred from the initial stage (several cycles to several tens of cycles). presented.

Comparative Example 2 A charge injection blocking layer, a photoconductive layer, and a surface layer were sequentially formed on an aluminum support using the same apparatus, the same conditions, and the same method as in Example. However, the second surface layer was not formed.

When the obtained electrophotographic photoreceptor was subjected to an image quality test at a copying conference, it showed clear images in the three environments at the initial stage (10 cycles due to several cycles).

On the other hand, in the initial image quality evaluation, approximately 20,000 copies were made in an environment of 20°C, 150% RH, and then the image quality was evaluated under a different environment.
Although clear images were obtained under the RH environment,
Under the environment of ℃/85%RH and 10℃/15%RH,
The image showed blurring.

Comparative Example 3 Image evaluation of the electrophotographic photoreceptor produced in Comparative Example 2 was performed in the same manner. However, the drum heating device in the printer was turned on to bring the drum surface to about 45°C.

In this case, clear images were shown in the three environments at the initial stage. On the other hand, for initial image quality evaluation, we performed a copying test of approximately 20,000 sheets in an environment of 20°C/150% RH, and then changed the printer installation environment and evaluated the image quality. %RH environment, clear images were obtained, but at 20°C/150%RH and 10°C/15%R
Under the H environment, image blurring occurred.

Effects of the Invention Since the electrophotographic photoreceptor of the present invention has the above-described structure, it provides a high-quality initial image and has excellent stability over time and printing durability. In addition, this electrophotographic photoreceptor is
It has excellent properties such as high photosensitivity in the visible light region, high dark resistance, excellent charging ability, and low dependence of characteristics on the environment in which it is used.

Therefore, the obtained copied image has excellent resolution and gradation reproducibility, and exhibits high image density without fog both at the initial stage and after a long period of repeated operations.

Furthermore, the electrophotographic photoreceptor of the present invention can be particularly advantageously used in an electrophotographic process in which at least the surface of the photoreceptor is heated to 35 to 50°C. In other words, when used with the photoconductor surface heated to the above range, it provides stable and high-quality initial positioning under any usage environment, and does not cause deterioration of image quality even after repeated operations. do not have.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing the structure of the electrophotographic photoreceptor of the present invention, and FIG. 2 is an explanatory diagram showing the general structure of an electrophotographic apparatus using the electrophotographic photoreceptor of the present invention. DESCRIPTION OF SYMBOLS 1... Support, 2... Charge injection blocking layer, 3... Photoconductive layer, 4... First surface layer, 5... Second surface layer, 6... Electrophotography photoreceptor for use, 7...charging means, 8.
...Latent image forming means, 9... Phenomenon means, 10... Transfer means, 11... Fixing means, 12... Cleaning means, 13... Transfer paper, 14... Photoreceptor heating means . Patent applicant Fuji Xerox Co., Ltd. Agent
Patent Attorney Senl Horabe Figure 1 Figure 2

Claims (5)

[Claims] (1) It is constructed by sequentially laminating a photoconductive layer, a first surface layer, and a second surface layer on a support, and the photoconductive layer is mainly made of amorphous silicon, and The first surface layer and the second surface layer each mainly consist of amorphous silicon doped with nitrogen atoms, and the nitrogen atom concentration in the second surface layer is higher than the nitrogen atom concentration in the first surface layer. A photoreceptor for electrophotography characterized by the following. (2) The photoconductive layer has a concentration of 0.1-100 ppm.
Claim 1 characterized in that it contains a group III atom.
The electrophotographic photoreceptor described in . (3) The electrophotographic photoreceptor according to claim 2, further comprising a charge injection blocking layer between the support and the photoconductive layer. (4) Electrophotography according to claim 3, wherein the charge injection blocking layer is amorphous silicon doped with Group III or Group V atoms in a range of 10-5000 ppm. Photoreceptor for use. (5) Claims 1, 2, 3, or 4 for use in an electrophotographic process in which at least the surface of the photoreceptor is heated to 35 to 50°C.
The electrophotographic photoreceptor described in .