JPS60455A - photoconductive member - Google Patents

Abstract

PURPOSE:To obtain a photoconductive member of which the electrical, optical and photoconductive characteristics are uniform over the entire part and with which a sharp image is obtd. with high resolution by suppressing the ruggedness on the surface of a photoconductive layer consisting of amorphous silicon composed essentially of Si within a specific range with respect to the thickness of the photoconductive layer. CONSTITUTION:A photoconductive layer 102 consisting of amorphous silicon composed essentially of Si and contg. H and halogen is formed on a base 101 to form a photoconductive member (photosensitive drum, etc.) 100 or a barrier layer 103 is provided by incorporating the III group, V group, O, C, etc. therein is provided on the base 101 and the layer 102 and a surface barrier layer 104 consisting of amorphous silicon contg. much C, N, etc. are successively laminated thereon to form the member 100. The ruggedness on the surface of the layer 102 or 104 with such photoconductive member is made max. <=1/2 for each 2.5mm. reference length of the surface roughness in accordance with JIS B0601 with respect to the average thickness of the layer 102. Then the photoconductive member which decreases the change in the surface roughness upon repetition of the repetitive electrostatic charging, exposing and developing, provides the stable image for a long period of time and has good cleaning property is obtd.

Description

Detailed Description of the Invention The present invention relates to a photoconductive member that is sensitive to electromagnetic waves such as light (herein, light in a broad sense refers to ultraviolet light, visible light, infrared light, X-rays, gamma rays, etc.). Regarding.

It is a highly sensitive photoconductive material that forms the photoconductive layer in solid-state imaging devices, electrophotographic image forming members in the image forming field, and document reading devices.

The SN ratio [photocurrent (Ip) / (Id), ] is high,
It has absorption spectral characteristics that match the spectral characteristics of electromagnetic waves to be irradiated, has fast photoresponsiveness, has a desired dark resistance value, is non-polluting to the human body when used, and is suitable for solid-state imaging devices. This requires characteristics such as being able to easily process afterimages within a predetermined time. Particularly, in the case of an electrophotographic image forming member incorporated into an electrophotographic apparatus used in an office as a business machine, the above-mentioned non-polluting property during use is an important point.

Based on this viewpoint, amorphous silicon (hereinafter referred to as a-
For example, German Publication No. 27489
No. 67 and No. 2855718 also disclose applications to electrophotographic image forming members.

German Published Publication No. 2933411 describes its application to photoelectric conversion/reading devices, and because of its excellent photoconductivity, resonance properties, heat resistance, and relatively easy expansion into large area, it is suitable for electrophotography. It is expected to be applied to image forming members for use in other applications.

However, the dark resistance value of a-9i alone is not high enough to be used as an electrophotographic image forming member, and a-9i is not coated with a blocking layer to prevent charge injection from the substrate or doped with additives. In many cases, high resistance is sought.

Further, the uniformity over the entire layer of the photoconductive member is also improved by the above-mentioned a-Si.
This is one of the important problems as well as the high resistance of the layer. For example, if there is uneven thickness of the photoconductive layer in a photoconductive member, density unevenness may occur in the image between thicker and thinner areas, and the photoconductive layer may be uneven. Differences in growth rate during layer formation may cause differences in electrical, optical, and photoconductive properties of the photoconductive layer. Furthermore, when defects such as pinholes are present on the surface of the photoconductive layer, problems often arise in terms of image quality, such as white spots in the image occurring in the defective areas and the failure to obtain beautiful images.

Furthermore, even if the surface of the photoconductive member has minute irregularities, it not only wears out the cleaning blade during cleaning or causes cleaning failure due to toner adhesion, but also causes damage during corona irradiation. , abnormal discharge may occur in the convex portion, resulting in a significant loss of image quality.

According to the studies of the present inventors, the manufacturing conditions that cause unevenness in the photoconductive layer are not limited to the surface unevenness itself, but are also caused by other electrical, optical, and photoconductive characteristic factors. 1. For example, charged potential, S
It is deeply involved in issues such as the N ratio and even image deletion. In addition, this can be said to be a characteristic based on the fact that the photoconductive layer is manufactured using a special manufacturing method such as plasma CVD, but the occurrence of such unevenness on the photoconductive layer is due to delicate manufacturing conditions.
.

It has also been found that if some cause of unevenness occurs during the manufacturing process, the unevenness will necessarily increase as the layer thickness increases.

The basic idea of dealing with unevenness on the surface of the photoconductive layer, which has such a large effect on the properties of the photoconductive material, is to first eliminate as much as possible the cause of the unevenness, and then to eliminate the cause of the unevenness as much as possible. In such cases, the following three points are raised: to suppress the growth as much as possible, and to find out to what extent the unevenness, which increases with the layer thickness, can be suppressed to withstand use as an image forming member. It will be done.

The present invention has been made in view of the above points, and from the viewpoint of applicability and applicability of a-3i as a photoconductive member used in electrophotographic image forming members, solid-state imaging devices, reading devices, etc. As a result of intensive comprehensive research and examination, we have developed an amorphous material that has a silicon atom as its base material and preferably contains at least one of hydrogen atoms (H) and halogen atoms (X), that is, so-called hydrogenated a-8i. Halogen-containing a-3i or halogenated a-5i (hereinafter, these will be collectively referred to as a-9i (H, X))
In a photoconductive member having a photoconductive layer containing the above, an extremely excellent photoconductive member can be obtained by suppressing irregularities on the surface of the photoconductive layer within a specific range with respect to the layer thickness of the photoconductive layer. This is based on the discovery that

The present invention has uniform electrical, optical, and photoconductive properties over the entire area of the photoconductive member, has few image defects such as image deletion, can produce clear halftones, and has high resolution.
It is an object of the present invention to provide an excellent photoconductive member capable of obtaining high-quality images.

Another object of the present invention is to provide a photoconductive member for electrophotography that does not cause wear of other electrophotographic parts such as a cleaning blade.

That is, the photoconductive member of the present invention includes a support and a photoconductive layer provided on the support and containing an amorphous material having silicon atoms as a matrix. The photoconductive layer is characterized in that the maximum height per standard length of 2.5 a+m of surface roughness based on JIS B 0801 is 172 or less of the average layer thickness of the photoconductive layer.

The photoconductive member of the present invention configured to have the structure described above can solve all of the problems described above, and has extremely excellent electrical, optical, and photoconductive properties. It has uniformity over the entire area.

In particular, when applied as an electrophotographic image forming member, its electrical properties are stable, there are few image defects such as image deletion, high density, and clear halftones.
Moreover, a high-resolution, high-quality visible image can be obtained, and in addition, other electrophotographic parts such as a cleaning blade are not worn out.

Hereinafter, the photoconductive member of the present invention will be explained in detail according to the drawings.

FIGS. 1 and 2 are diagrams schematically showing a layer structure for explaining an embodiment of the structure of a photoconductive member of the present invention.

The photoconductive member 100 of the present invention is a photoconductive member having a-5i()1.
A photoconductive layer 102 containing X) as a main component is formed and configured. The photoconductive layer 102 has a barrier layer 103 .contacting the photoconductive layer 102 as shown in FIG. Furthermore, a surface barrier layer 104 may be provided on the surface of the photoconductive layer. In the present invention, unless otherwise specified, the barrier layer 103 and the surface barrier layer 104 are also included in the photoconductive layer 102 and are referred to as a photoconductive layer.

The support used in the present invention may be electrically conductive or electrically insulating. Examples of the conductive support include NiCr, stainless steel, and AI.

Cr, No, Au, Nb, Ta, V, T
Examples include metals such as Pt, Pd, and alloys thereof.

As the electrically insulating support, films or sheets of synthetic resins such as polyester, polyethylene, polycarbonate, cellulose acetate, polypropylene, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyamide, glass, ceramic, paper, etc. are usually used. .

The shape of the support is determined as desired, but for example, if the photoconductive member 100 of FIG. The thickness of the support, which is preferably belt-shaped or cylindrical, is determined as appropriate so that the desired photoconductive member is formed, but if flexibility is required as a photoconductive member, However, in such cases, from the viewpoint of manufacturing and handling of the support, as well as mechanical strength, etc., it is usually thinner. teeth,! 〇- or more.

In the present invention, in order to form a photoconductive layer composed of a-5i (H, A vacuum deposition method is applied.

Specifically, the halogen atoms (X) that may be contained in the photoconductive layer of the photoconductive member of the present invention include fluorine, chlorine,
Mention may be made of bromine and iodine, particularly chlorine, especially fluorine. Light guide @yi
Components other than silicon atoms, hydrogen atoms, and halogen atoms contained in ro2 include pre-m atoms such as boron and gallium as components that adjust the forbidden band width and Fermi level, etc.
V atoms such as nitrogen, phosphorus, arsenic, oxygen atoms, carbon atoms,
Germanium atoms and the like can be contained alone or in appropriate combinations.

The barrier layer 103 is provided for the purpose of improving the adhesion between the light guide @@102 and the intermediate layer or adjusting the charge-accepting ability, and depending on the purpose, it may contain m-preatoms, V-preatoms, oxygen atoms,
a-9i (H,
) layer or microcrystalline-9i(H,X) layer is formed in one layer or in multiple layers.

Further, as a surface charge injection prevention layer or a protective layer on the photoconductive layer 102, an upper layer made of amorphous silicon containing a large amount of carbon atoms, nitrogen atoms, oxygen atoms, etc. or a surface barrier layer made of a high-resistance organic substance. 104 may be installed.

Next, the unevenness on the surface of the photoconductive layer 102 (or the surface barrier layer when the surface barrier layer 104 is provided on top of the photoconductive layer) is adjusted to a specific range with respect to the average layer thickness of the photoconductive layer. We will explain each specific factor to suppress the above.

According to many experiments conducted in the present invention, it has been found that one of the factors that greatly influences the occurrence of unevenness in the photoconductive layer is the surface shape of the support. If minute irregularities exist on the surface of the support, the uniformity of the deposited film will decrease.
Columnar structures and spherical protrusions are likely to be formed, and the surface roughness of the photoconductive layer increases accordingly. Therefore, the surface properties of the support are a very important factor. However, in the past, aluminum cylinders were exclusively used, and furthermore, due to the performance of polishing equipment, it was not possible to use supports with very good surface precision. This is also the reason why optimization has been neglected.

Other factors that influence the occurrence of unevenness in the photoconductive layer include:
One example is the plasma state during discharge. For example, if an abnormal discharge occurs at the start of discharge, the intensity distribution of the gas plasma or radicals or ions required near the drum base cylinder, which is the internal electrode, will change significantly. Therefore, even if the discharge stability during steady state is excellent, the formed photoconductive layer ends up having large irregularities.

In addition, gases, ions, and radicals that have acquired significantly large amounts of energy due to abnormal discharge may attack the substrate surface and form irregularities, so it is extremely important to properly control the plasma state during discharge.

In addition, abnormal growth of the deposited film using impurities as nuclei is also a strong cause of the occurrence of unevenness in the layer, and such impurities include 1. Examples include powders such as

Furthermore, almost all of the manufacturing conditions of the photoconductive layer, such as the absolute value of the discharge power, the gas flow rate, and the substrate temperature, influence the occurrence of unevenness in the film in some way. For example, if we look at the gas flow rate, if the gas flow rate is too small, the growth of columnar structures and spherical protrusions will be increased when they are formed, and conversely, if the gas flow rate is too large, a dense deposited film will not be obtained. , the unevenness of the film surface increases.

In this way, it is only by appropriately adjusting the surface shape of the support, the exclusion of impurities, the stabilization of the plasma state during discharge, and the manufacturing conditions of various photoconductive layers that JIS B of the photoconductive layer can be achieved. The photoconductive member of the present invention can be manufactured in which the maximum height of the surface roughness based on OHI per reference length of 2.5 cm is suppressed to within 1i2 of the average layer thickness of the photoconductive layer.

In the present invention, the surface roughness of the photoconductive layer is measured by measuring the maximum height at any position on the surface of the photoconductive layer at least 10 times if the photoconductive member is a flat plate. It is carried out by calculating the maximum value, and if it is drum-shaped,
This is carried out by finding the maximum value of at least 10 measurements in a direction parallel to the drum axis at any position.

Regarding the surface roughness of the photoconductive layer, it is preferable that the absolute value of its maximum height is as small as possible, and in particular, the cleaning performance is highly dependent on the absolute value of the maximum height. However, it is not always appropriate to discuss the electrical, optical, and photoconductive properties of the photoconductive layer only in terms of the absolute value of the maximum height, but rather in the relative relationship with the average layer thickness of the photoconductive layer. In order to form a photoconductive layer having good properties, it is important to suppress the amount below. That is, an excellent photoconductive member can be obtained by suppressing the maximum height of surface roughness to within 1i2 of the average layer thickness of the photoconductive layer. Therefore, even if the absolute value of the maximum height is made considerably small, if the average layer thickness of the photoconductive layer is thin and the maximum height exceeds 1/2 of the average layer thickness, the above-mentioned uniformity of the deposited film will be affected. The characteristics of the photoconductive layer deteriorate due to the formation of columnar structures and spherical protrusions.

Next, an example of a method for manufacturing a photoconductive member using a glow discharge decomposition method will be described.

Figure 3 shows an apparatus for manufacturing photoconductive members using the glow discharge decomposition method.
shows.

Gas cylinders 1102 to 110B in the figure are sealed with raw material gas for forming the photoconductive layer of the photoconductive member of the present invention.
) 1 gas (purity 99.98%) cylinder, 1103 is BH gas (purity 99.99%, hereinafter BH/H
1104 is N)l scum (purity 9)
L99%) cylinder, +105 is C)l gas (purity 89
．． 89%) cylinder, 1108 is SiF gas (purity H, 9
9%) It is a cylinder. Although not shown in the drawings, it is possible to add other desired gas types as needed.

In order to flow these gases into the reaction chamber 110.1, each valve 1122-11 of the gas pump 1102-110B is
2B and leak valve 1135 are closed, and also inlet valves 1112-ttte, outlet valves 1117-1121 and auxiliary valves 1132.11.
33 is open, first open the main valve 1134 and open the reaction chamber! 101 and gas piping. Next, the reading on the vacuum gauge 1136 is approximately 5X 10'
When it becomes torr, auxiliary valve 1132.1133
and outflow valve! Close 117-112+. Next, SiH gas from gas pump 1102, gas pump 1103
From B H/H gas, gas pump 1104 N) I
CH gas, gas pombe 1 from scum, gas pombe 1105
106 to each valve 1122-t.
Open t2e and adjust the pressure of the outlet pressure gauges 1127 to 1131 to 1Kg/cm2, and then open the inflow valves 1112 to 1.
Gradually open 11B and install mass flow controller 1107.
~1111. Subsequently, the outflow valve 11
17 to +121 and auxiliary valves 1132 and 1133 are gradually opened to allow the respective gases to flow into the reaction chamber 1101. The outflow valves 1117 to 1121 are adjusted so that the ratio of these gas flow rates at this time becomes a desired value, and
Vacuum gauge 1138 is installed so that the pressure inside the reaction chamber reaches the desired value.
Adjust the opening of the main valve 1134 while checking the reading. After confirming that the temperature of the gas cylinder 1137 is set to 50 to 400° C. by the heater 1138, the power source 1140 is set to a desired power to generate glow discharge in the reaction chamber 1101.

Further, during layer formation, it is desirable that the base cylinder 1137 be rotated at a constant speed by the motor 1138 in order to ensure uniform layer formation.

To form a photoconductive layer made of a-9i (Hl) by a reactive sputtering method or an ion blasting method, for example, in the case of a sputtering method, a target made of Si is used and the target is spun into a predetermined cast. In the case of sputtering gray or ion blating methods in a plasma atmosphere, polycrystalline silicon or single crystal silicon is housed in a deposition boat as an evaporation source, and this silicon evaporation source is used by resistance heating method or electron beam method (EB method). This can be carried out by heating and evaporating the flying evaporated material by, for example, passing through a predetermined gas plasma atmosphere.

Examples will be described below.

Example 1 A lathe with an air damper for precision cutting manufactured by PNEUMO PRECLSION ING was equipped with a tip curvature of 0.01 (am
') was set to obtain a negative rake angle of 5° with respect to the Schilling center angle. Next, an aluminum cylinder was vacuum chucked to the rotating shaft flange of this lathe, and while white kerosene was sprayed from an attached nozzle and chips were sucked from the attached vacuum nozzle, the circumferential speed was increased to 1000 (+I+/+in). .

Mirror cutting was performed at a feed rate of 0.01 (mm/R). The same cylinder was subjected to a surface roughness measurement device and the maximum height was measured 10 times per standard length of 2.5 m in the axial direction, and it was confirmed that the maximum height was within 0.02 μ. .

Next, a photoconductive layer was formed on the same cylinder under the conditions shown in Table 1 using the manufacturing apparatus shown in FIG. 3, which was detailed above.

Due to the surface roughness of this photoconductive member, the standard length 2 in the axial direction
．． When the maximum height around 5cm was measured 10 times, the maximum height was within 2. When this photoconductive member was placed in a copying machine and an image was produced, a good image quality with few image defects was obtained.

Next, after performing the above-mentioned image forming process 100,000 times, a similar image evaluation was performed, and a good image quality that was almost the same as the initial state was obtained. Furthermore, when the cleaning blade at this time was inspected, it was found that it was hardly worn.

Examples 2 to 5 and Comparative Examples 1 to 2 The lathe used in Example 1 was used, except that the peripheral speed and feed rate were changed to change the surface properties of the aluminum cylinder substrate as shown in Table 2. A photoconductive layer was formed under exactly the same conditions as in Example 1. The photoconductive member thus obtained was evaluated in the same manner as in Example 1, and the results shown in Table 2 were obtained.

Example 6 The photoconductive member manufacturing apparatus shown in FIG. 3 was partially modified,
By removing all protrusions such as heaters from the electrodes in the chamber and rounding all exposed edges, we created a prototype reactor in which no abnormal discharge of any kind was observed around the cylinder. A photoconductive layer was formed under exactly the same conditions as in Example 1, except for using such a reaction apparatus and using the aluminum syringe produced in Example 1 and having a maximum surface roughness of 0.02 μ. When the thus obtained photoconductive member was evaluated in the same manner as in Example 1, it was confirmed that, as in Example 2, the maximum height was within 0.8 μm.

Example 7.8 and Comparative Example 3 Using the lathe used in Example 1, the aluminum cylinder was moved at a circumferential speed of 333 (m/l 1 in) and a feed rate of 0.03.
(mm/R), and a photoconductive layer was formed on the cylinder under the same conditions as in Example 1, except that the layer thickness was changed. The photoconductive member thus obtained was evaluated in the same manner as in Example 1, and the results shown in Table 3 were obtained.

Comparative Example 3 Using a so-called general-purpose lathe with a pole bearing type bearing and no anti-vibration measures, a diamond R cutting tool was used for the tool cutting edge, and the circumferential speed was 45 (+s/■i).
n) When an aluminum cylinder was polished at a feed rate of 0.5 (m/R), the maximum height per standard length of 2.5 m + m in the axial direction was measured 10 times, and the maximum height was The value was 0.54. Using this cylinder, a photoconductive member manufacturing apparatus using the glow discharge decomposition method shown in Fig. 3 installed outside the clean room was used under the conditions of power 500W, SiH gas flow rate 509CCM, and substrate temperature 250℃. A photoconductive member with a photoconductive layer having a layer thickness of 20 mm was produced. At this time, the surface roughness of the photoconductive layer was measured in the axial direction at the maximum height per reference length of 2.51 ゛1G.
When I went around it, I found many cylinders with a maximum height of 10u or more.

When this photoconductive member was set in a copying machine and an image was printed, roughness was already observed in the initial image quality, and after approximately 2,000 image printing durability tests, the blade was significantly worn, resulting in poor cleaning. confirmed.

It was also confirmed that abnormal discharge occurred due to corona irradiation, pinholes were generated, and many image defects were caused.

Table 3 (2) Evaluation criteria are the same as in Table 2.

[Brief explanation of the drawing]

FIGS. 1 and 2 are diagrams schematically showing a layer structure for explaining an embodiment of the structure of a photoconductive member of the present invention. FIG. 3 is a diagram showing an apparatus for manufacturing a photoconductive member using a glow discharge decomposition method. 100: Photoconductive member 101: Support 102: Photoconductive layer 103: Barrier layer 104: Surface barrier layer 1101: Reaction chamber 1102-1
106: Gas cylinder 1107-1111: Mass flow controller 1112-
1118: Inflow valves 1117-1121: Outflow valves 1122-1128: Valves 1127-1131: Pressure regulator

Claims (1)

[Claims] In a photoconductive member having a support and a photoconductive layer provided on the support and containing an amorphous material having silicon atoms as a matrix, the surface roughness of the photoconductive layer is based on JIS BO301. A photoconductive member characterized in that the maximum height per reference length of 2.511 m is 172 or less of the average layer thickness of the photoconductive layer.