JPS5967552A - Recording body - Google Patents

Abstract

PURPOSE:To provide an electrophotographic material which exhibits excellent sensitivity to light in visible and IR regions by providing a specific electric charge blocking layer, electric charge transfer layer, photoconductive layer and surface reforming layer on the substrate of said material. CONSTITUTION:An electrostatic charge blocking layer 2 of 100Angstrom -1mum thickness consisting of nitrogen atom-contg. amorphous hydrogenated and/or fluorinated silicon carbide is formed on a backing substrate 1. An electric charge transfer layer 3 of 2-80mum thickness consisting of amorphous hydrogenated and/or fluorinated silicon is formed on the layer 2. A photoconductive layer 5 of 0.3- 5mum thickness consisting of nitrogen atom-contg. amorphous hydrogenated and/or fluorinated silicon is further formed on the layer 3. A surface reforming layer 4 of 100-5,000Angstrom thickness consisting of an inorg. material is formed on the layer 5. Since the layer 5 is formed of nitrogen atom-contg. a-Si in the above- mentioned way, said layer exhibits excellent sensitivity of the light in visible and IR regions by controlling the quantity of nitrogen and the intrinsic resistance is controlled as desired with the quantity of nitrogen and the rate of impurity doping.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a recording medium, such as an electrophotographic photoreceptor.

Conventionally, as an electrophotographic photoreceptor, Ses or Se is mixed with As,
Photoreceptor doped with Te1Sb etc., ZnO or CdS
Photoreceptors, etc., in which the compound is dispersed in a resin binder are known. However, these photoreceptors have problems in terms of environmental pollution, thermal stability, and mechanical strength. On the other hand, electrophotographic photoreceptors using amorphous silicon (a-3t) as a base material have been proposed in recent years. a-3i is St.
It has a so-called dangling bond in which the -Si bond is broken, and many localized levels exist within the energy gap due to this defect. For this reason, hopping conduction of thermally excited carriers occurs, resulting in a small dark resistance, and photoexcited carriers are trapped in localized levels, resulting in poor photoconductivity. The dangling bonds are filled by bonding H to St by compensating with .

Such amorphous hydrogenated silicon (hereinafter a--
It is called 3i:H. ) has a resistivity of 108 to 10 in the dark.
9Ω-crn, which is about 1/10,000 times lower than that of amorphous Se. Therefore, a photoreceptor made of a single layer of a-8i:H has the following problems: the dark decay rate of the surface potential is high and the initial charging potential is low. However, on the other hand, when irradiated with light in the visible and infrared regions, the resistivity is greatly reduced, so it has extremely excellent properties as a photosensitive layer of a photoreceptor.

Therefore, in order to impart potential holding ability to such a-8i:H, the resistivity was increased to about 10 by doping with boron.
It can be increased to 12Ω-tooth, but it is not easy to control boron M so precisely, and
Even with a resistivity of about 12 Ω-α, the photosensitivity is insufficient for use in a photosensitive process using the Carlson method, and the charge retention property is still insufficient. Furthermore, by adding a small amount of oxygen together with boron, it is possible to increase the resistance to about 1013Ω-α, but when this is used in a photoreceptor, the photoconductivity decreases, causing worsening of edge breakage and residual The problem arises of potential generation.

In addition, photoreceptors with a-8i:H surfaces are susceptible to surface chemical stability, such as the effects of long-term exposure to the atmosphere and moisture, and the effects of chemical species generated by corona discharge. , has not been sufficiently investigated so far. For example 1
It is known that if a device is left for more than a month, it will be affected by moisture and its receptive potential will drop significantly. Furthermore, a-3i:H
has poor film adhesion (adhesion) to supports such as Al and ζ stainless steel, which poses a problem in practical use as electrophotographic photoreceptors. As a countermeasure against this, a silane coupling agent such as that disclosed in JP-A-55-87154, JP-A-56-74
A-34:H
It is known to provide it between a layer and a support. However, in these cases, it is necessary to form the adhesive layer and to form the a-3i:H layer using different methods, which requires the use of new film forming equipment, resulting in poor workability. Become.

Moreover, in order to make the a-5iSH layer good in photoconductivity, the temperature of the substrate (support body) during film formation is usually about 200°C.
℃ or higher, but the underlying adhesive layer cannot thermally withstand such temperatures.

On the other hand, forming a photoconductive layer using nitrogen atom-containing a-3i:H (hereinafter sometimes referred to as a-8iN:H), in which nitrogen atoms are contained in a-3i:H, was disclosed in Japanese Patent Application Laid-Open No. It is described in each specification of No. 54-145539 and Japanese Patent Application Laid-open No. 57-37352.

This known a-8iN:H layer can increase the dark specific resistance Po to about 1X10"Ω-QM by doping with boron, and also has excellent photoconductivity (sensitivity). However, the inventors of the present invention According to the study of the above-mentioned known photoreceptor, it was found that injection of unnecessary charge from the conductive support into the a-3iN:H layer is likely to occur.
It is not easy to control the amount of boron doped into -3iN:H, and for this reason, it is difficult to maintain the charging potential (in other words, increase the resistance of the photoconductive layer) with good reproducibility (sufficient luminescence). Furthermore, there are examples in which a surface coating layer is provided on the a-8iN:H layer, but since the surface coating layer is only made of synthetic resin, it has poor printing durability and heat resistance. It was also found that the stability of electrophotographic properties during repeated use, chemical stability of the surface, mechanical strength, etc. were not sufficient.

Moreover, the above-mentioned surface coating layer tends to absorb or reflect light that should be incident on the a-3iN:H layer, and therefore has the disadvantage of reducing photosensitivity.

The present invention was made in order to correct the above-mentioned defects, and includes a substrate (for example, a conductive support such as Ad) and a nitrogen atom-containing amorphous hydrogenated and/or fluorinated substrate formed on the substrate. Silicon (e.g. a-8iN:
H) with a thickness of 10 μm or fluorinated silicon carbide (e.g. a-3iC:H) with a thickness of 2 to 80 μm
a charge transport layer of 0.3 to 5 μm in thickness and made of nitrogen atom-containing amorphous hydrogenated and/or fluorinated silicon (e.g. a-3iN:H) formed on the charge transport layer.
100 to 500 mm thick, consisting of a photoconductive layer and an inorganic material (e.g. Si 02 ) formed on the photoconductive layer.
The present invention relates to a recording medium characterized by comprising a long surface modified layer.

According to the present invention, since the photoconductive layer is formed of nitrogen-containing a-3i, it exhibits excellent sensitivity to visible and infrared light by controlling the amount of nitrogen, and the specific resistance can be controlled by controlling the amount of nitrogen. This can be done arbitrarily by adjusting the amount of impurity doping. In particular, doping with boron etc.
Since it exhibits an FD of 10Ω or more, it becomes a photosensitive layer with excellent photosensitivity and potential holding ability.

Moreover, since a blocking layer made of a-3iN is provided under the charge transport layer, compared to the case without this,
By preventing unnecessary injection of carriers from the substrate, the ability of the photoreceptor to retain the charged potential can be significantly improved, and the adhesiveness with the substrate can also be improved.

Moreover, since a charge transport layer made of a-3iC is provided under the photosensitive conductor layer, the ability to retain the charged potential of the photoreceptor is significantly improved due to the high resistance a-3iC compared to the case without this layer. In addition, the carriers from the photoconductive layer have high mobility and long life, allowing them to move efficiently (to the support side). has a non-bar-free material rib as a surface modification layer, but this inorganic material layer has high heat resistance and surface hardness, which improves printing durability, thermal resistance, photosensitivity, and stability of electrophotographic properties during repeated use. properties, chemical stability of the surface of the photoreceptor, mechanical strength, prevention of changes over time during storage, etc. can be significantly improved.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below with reference to the drawings.

1 to 3 illustrate the structure of a photoreceptor.

The photoreceptor in FIG. 1 is mounted on a conductive support substrate 1 such as A1.
A high resistance charge blocking layer 2 made of intrinsic type a-3iN:H, a charge transport layer 3 made of a-8iC:H, and a
It has a structure in which a photoconductive layer 5 made of -8iN:H and a surface modified layer 4 made of an inorganic material (for example, Sin) are laminated in sequence.

In particular, the photoconductive layer 5 has a nitrogen atom content of 1 to 3° atoms.
ic 96 (preferably 15-25 atomic%)
As shown in FIG. 4, the dark resistivity P
D and resistivity during light irradiation? The ratio with L is sufficient, and the photosensitivity (particularly to light in the visible and infrared regions) becomes good. In addition, the periodic table 11 [A group element, for example, boron, the flow rate ratio (B, , Ho/SiH,) = 1 to 5oo
It can be seen that by doping with pa, the resistivity can be increased to 1010 Ω-α or more (and 10'2 Ω-α or more) as shown in FIG. By increasing the resistance, the charge retention ability can be improved. As a result, a photoconductive layer having good photosensitivity and potential holding ability can be obtained.

For comparison, the resistance change due to impurity doping to a-8t:H is shown by a broken line in FIG.
In this case, the degree of high resistance is insufficient, and moreover, the resistance is 1010Ω.
A stable high resistance value can only be obtained at -CIIL level. Also, as understood from Fig. 4, a-3i
In N:H, ρ can also be controlled by the amount of nitrogen, and in combination with impurity doping, the range of resistance control can be widened.Also, as shown in FIG. The optical energy gap (
a-8i: In the case of H, increase approximately 1.65ev),
It can be seen that the absorption characteristics of incident light can be controlled.

The blocking layer 2 has a nitrogen atom content of 5 to 50
atomic% (preferably 10-40atOmiC
%). Furthermore, as shown in FIG. 5, the resistivity is increased (intrinsic) to 10@13 .OMEGA.-m or more by light doping with an element of group 1A of the periodic table, so that the charged potential retention ability of the photoreceptor can be improved. In order to enhance the blocking effect, as shown in Fig. 5, a-3ilN: HEi 2 can be made into an N-type as shown in Fig. 2 by doping with a Group VA element (e.g. phosphorus) of the periodic table, especially when negatively charged. The injection of holes from the substrate is sufficiently prevented.The amount of phosphorus doped for this purpose is expressed as a flow rate ratio: P H3 / SiH4 = 10 to 1
It is preferable to set the resistance to 0,000 p (51) D at 10'Ω-m or more). In addition, in order to sufficiently prevent the injection of electrons from the substrate during positive charging, as shown in FIG.
It is preferable to dope it with 00 to 100,000 pptn to make it a P type (or even a P+ type) as shown in FIG.

The charge transport layer 3 has a carbon atom content of 5 to 90 at.
omic% (preferably 10-50 atomic
%), ρD=1012~1013Ω
-α, which increases the resistance and improves the charged potential retention ability of the photoreceptor. The photocarriers injected from the photosensitive layer 5 move in the charge transport layer 3 with high mobility and lifetime, and can reach the support 1 efficiently, so that the charge transport property is greatly improved. In addition, as shown in FIG.
When doped with 2 Ha/Si H4 = 1 to 500++ pm, the PD can be increased to 1013 Ω-m or more, thereby further improving the charging potential and charge transport ability.

Further, regarding the surface modified layer 4, its specific resistance is 1
It is desirable that the surface potential be at least 0.013Ω-α in order to improve the surface potential retention ability. Usable construction materials include SIO
s 5102, A 120s, MgO, ZnO.

PbO, Cab, Bed, BaO1ZrO2, Tl
A few selected from the group consisting of O2, 'f'a 20 s, CeO, .

There is also an appropriate range for the thickness of each layer of the photoreceptor described above, and the thickness of the photoconductive layer 3 is 0.3 to 5 μm (preferably 0.5 to 5 μm).
3μ7n), the blocking layer 2 has a thickness of 1ooX to 1μm (preferably 400 to 5000X), and the charge transport layer 3 has a thickness of 2 to 8μm.
0 μm thickness (5 to 30 μm), surface modified layer 4 is 10 μm
It should be 0-5oooX (preferably 400-2000X). If the thickness of the photoconductive layer 3 is less than 0.3μ7n, it will not be able to absorb light sufficiently, and the photosensitivity will decrease.
It is practically inappropriate to exceed μm. Charge transport layer 3
If the length is less than 2 μm, there is no effect, and if it exceeds 80 m, it is not practical and takes time to form the film.

Furthermore, if the surface modification layer 4 has a density of less than 1ooX, it will not be effective, and if it exceeds 50,001, the photosensitivity will decrease, residual potential will increase, etc., which will be inappropriate. Blocking layer 2 is 1oo
If it is less than X, there will be no blocking effect, and if it exceeds 1 μm, the charge transport ability will be poor.

Note that each of the above layers needs to contain hydrogen, but if they do not contain hydrogen, the charge retention characteristics of the photoreceptor will not be practical. Therefore, the hydrogen content is 1 to 40 atomic% (and even 10 to 30 atomic%).
atomic%).

In particular, the hydrogen content in the photoconductive layer 3 is essential to compensate for dangling pounds and improve photoconductivity and charge retention, and is usually 1 to 40 atomic.
%, and more preferably 3.5 to 20 atomic%. Also, as doping impurities, in addition to boron, Al, Ga, In, T1, etc.
Group elements can be used, and in addition to phosphorus, As 5SbSBi
It is possible to dope the members of Group VA of the periodic table, such as

In addition, in order to compensate for dangling problems, fluorine can be introduced in place of the above-mentioned H or in combination with H.
-8iN:H:F1a-5iC:F, a -3iC
:H:F can also be used. In this case, the amount of fluorine is 0
, 01-20 atomic% is good, 0.5-20 atomic%
10 atom I C96 is more desirable.

Next, the method and apparatus (glow discharge apparatus) for manufacturing the above-mentioned photoreceptor will be explained with reference to FIG.

In the vacuum chamber 12 of this apparatus 11, the above-described substrate 1 is fixed on a substrate holding part 14, and the substrate 1 can be heated to a predetermined temperature with a heater 15. A high frequency electrode 17 is disposed facing the substrate 1, and a glow discharge is generated between the high frequency electrode 17 and the substrate 1. In addition, 20.21.22.2 in the figure
3.24.25.27.28.29.30.31.37
．． 38.40 is each valve, 32 is a source of S i H4 or gaseous silicon compound, 33 is a source of nitrogen such as NH8 or N2, 34 is a source of hydrocarbon gas such as CH, 35 is Ar or A carrier gas supply source such as H2, etc., and 36 a supply source of impurity residue (for example, B2H6 or PH3). In this glow discharge device, first, the surface of a support, for example, an Al substrate 1, is cleaned, and then placed in a vacuum chamber 12, and the valve 37 is adjusted to exhaust the gas so that the gas pressure in the vacuum chamber 12 becomes 1σ6 Torr. , and the substrate 1 is heated and maintained at a predetermined temperature, for example, 30 to 400°C. Next, using a high-purity inert gas as a carrier gas, SiH or a gaseous silicon compound, a mixed gas prepared by diluting an appropriate amount of N I-T3 or N2, and CH, PH3, 82H6, etc., are suitably introduced into the vacuum chamber 12. For example, 0.01 to 10
A high frequency voltage (for example, 13.561 vIHz) is applied by the high frequency power supply 16 under a reaction pressure of Torr. As a result, each of the above reaction gases is decomposed by glow discharge to form a type, N type or P type a-8iN: H, a-8iC:
a-8iN:H containing Hl hydrogen in the above layer 2.3.
5 and sequentially deposited on the substrate. At this time, a-8ix-xNx :H having a desired composition ratio and optical energy gap can be obtained by appropriately adjusting the flow rate ratio of the silicon compound and the nitrogen compound or carbon compound and the substrate temperature.
, a-8ir-yCy :H can be precipitated,
Furthermore, it is possible to deposit at a rate of 100 OX/min or more without significantly affecting the electrical properties of the deposited film. The surface modified layer 4 can be formed by, for example, a sputtering method, a vacuum evaporation method, or the like. In the case of the sputtering method, a thin film of 5i02 may be formed by using a target of, for example, 5in2, introducing a sputtering gas such as Ar gas into the deposited layer, and performing sputtering. The pressure of the Ar atmosphere may be in any range as long as glow discharge can be maintained, and is generally 0.01 to ljl Torr, preferably 0.1 to 1.0 Torr in order to obtain stable discharge.

a-8iN:H/a-3iC:H/aSi according to the invention
For photoreceptors with a basic structure of N:H/SiOt, especially a-3iC:H and a-3iN:H, each layer can be sequentially formed using the same device by simply changing the type and flow rate of the reaction gas used. It can be created by

The above manufacturing method is based on the glow discharge decomposition method, but there are also sputtering methods, ion blating methods, and methods in which Si is evaporated while introducing activated or ionized hydrogen in a hydrogen discharge tube. (In particular, Japanese Patent Application Laid-Open No. 56-78413 (Patent Application No. 54-15) filed by the present applicant)
The above photoreceptor can also be manufactured by the method of No. 2455).

In addition to SiH, the reaction gas used is 5i2)TS.
Lower hydrocarbon gases such as iF4, 5iHFs, Hasono derivative scum, and C2Ha and CsHa other than CH4 can be used.

FIG. 9 shows a photoreceptor according to the present invention in the above-mentioned Japanese Patent Application Laid-Open No. 56-78.
413 shows a vapor deposition apparatus used for fabrication by the vapor deposition method of No. 413.

A vacuum pump (not shown) is connected to the Pel jar 41 via an exhaust pipe 43 having a butterfly valve 42, thereby causing the inside of the Pel jar 41 to be heated, for example, from 10-3 to 10".
' A TorrO high vacuum state is established, and the substrate 1 is placed inside the Pel jar 41 and heated to a temperature of 1 by the heater 45.
While heating to 50-500°C, preferably 250-450°C, the substrate is heated to 0-10KV using a DC power supply 46.
A negative direct current voltage, preferably -1 to -6 KV is applied, and active hydrogen and hydrogen ions are discharged from a hydrogen gas discharge tube 47, which is connected to the Pelger 41 with its outlet facing the substrate 1. 41, the silicon evaporation source 48 and, if necessary, the aluminum evaporation source 49 provided opposite to the substrate 1 are heated, and the shutters S above each are opened, so that the evaporation rate ratio of silicon and aluminum is, for example, 1. : Simultaneously evaporate at an evaporation rate of 10.4, and into the Pelger 41, the discharge tube 50
NH3 gas or CH4 gas activated by is introduced, thereby forming a-8iN:H layer 2.5, a-8iC:
An H layer 3 (see FIGS. 1 to 3) is formed.

The structure of the discharge tube 47, 50 is shown in FIG. 10, for example, as shown in FIG.
A discharge space member 64 made of, for example, cylindrical glass, which surrounds the discharge space 63 and is provided at one end, and another ring-shaped electrode member 66 having an outlet 65 and provided at the other end of this discharge space member 64. By applying a DC or AC voltage between the one electrode member 62 and the other electrode member 66, for example, hydrogen sludge supplied via the scum 61 causes a glow discharge in the discharge space 63. As a result, active hydrogen consisting of hydrogen atoms or molecules activated by electron energy and ionized hydrogen ions are discharged from the outlet 65. The discharge space m1iU in this illustrated example
'64 has a double pipe structure that allows cooling water to flow through it, and 67.68 indicates the cooling water inlet and outlet. 6
9 is a cooling fin for one electrode member 62. The distance between the electrodes in the hydrogen gas discharge tube 47 is 10 to 15 F, the applied voltage is 600 V, and the pressure in the discharge space 63 is about 10-2 Torr.

Next, examples of the present invention will be specifically described.

An A1 substrate cleaned with trichlorethylene and etched with a 0.1% NaOH aqueous solution and a 0.1% HNO3 aqueous solution was subjected to glow discharge as shown in FIG. Set in the device, 1O inside the reaction tank
Evacuate to a high vacuum level of -5 Torr and set the support temperature to 20
After heating to 0°C, high-purity Ar gas was added to 0.5To
Under a back pressure of rr, high frequency power with a frequency of 13.56 MHz and a power density of 0.04 W/ was applied, and preliminary discharge was performed for 15 minutes. Then, SiH.

A reaction scum consisting of P and N2 or CH4 is introduced, and P
By adding H, or B, H gas and decomposing it by glow discharge, carrier injection can be prevented and a-
A 3iN:H layer and a-3iC:H layer were formed. In forming the photoconductive layer, SiH4, N2 and B if necessary are used.
2Ha was subjected to discharge decomposition to form an a-3iN:H photosensitive layer. The surface modified layer 4 can be formed by, for example, a sputtering method, a vacuum evaporation method, or the like. In the case of the sputtering method, for example, a target made of S s O2 is used, a sputtering gas such as Ar gas is introduced into the end layer, and sputtering is performed to form a thin film of 5 in 2. Good. The pressure of the Ar atmosphere may be in any range as long as glow discharge can be maintained (generally 0.01 to 1.0 Torr, preferably 0.1 to 1.0 Torr in order to obtain stable discharge).

The electrophotographic photoreceptor thus prepared was mounted on an electrometer model 5P-428 (manufactured by Kawaguchi Electric Co., Ltd.).
The voltage applied to the discharge electrode of the charger was 6 KV, and the charging operation was performed for 5 seconds. Immediately after this charging operation, the charging potential on the surface of the photoreceptor was 2.

(V), and the amount of irradiation light necessary to attenuate this charge level is halved.
). The optical attenuation curve of the surface potential becomes flat at a certain finite potential, but may not become completely zero, or this potential is called a residual potential VR (V). In addition, regarding image quality, the photoreceptor was made into a drum shape, and 20°C 160%
Electrophotocopying machine U-BixV (Konishi Roku Photo Industry) at RH
Co., Ltd.), print the image, and improve the initial image quality (100
The image quality after 0 copies (at one time) and when used multiple times (at 200,000 copies) was evaluated as follows.

Image density 1.0 or more ◎ (Very good image quality) =
0.6 to 1.0 0 (good image quality) to 0.
Less than 6 △ (blurring occurs in the image) x (density is extremely low and cannot be distinguished) Each photoreceptor according to the present invention is shown in the table below together with a comparative example, but the photoconductive layer (photosensitive layer) is doped with impurities and the amount of nitrogen is When controlled, the characteristics are significantly improved. It can be seen that good results can be obtained by appropriately selecting the composition and thickness of this photosensitive layer, blocking layer, charge transport layer, and surface modification layer.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, and FIG. 1, FIG. 2, and FIG. 3 are three cross-sectional views of the photoreceptor, and FIG. 4 shows the resistance of a-3iN:H depending on the amount of nitrogen. A graph showing changes in the resistance of a-8i(N):H due to impurity doping. FIG. 6 is a graph showing changes in the optical energy gap of a-8iN:H depending on the amount of nitrogen. Fig. 7 is a graph showing the resistance change of a -5iC due to boron doping, Fig. 8 is a schematic cross-sectional view of a glow discharge device, Fig. 9 is a schematic cross-sectional view of a vacuum evaporation device, and Fig. 10 is a cross-sectional view of a gas discharge tube. , FIG. 11 is a diagram showing each characteristic of the photoreceptor. In addition, in the symbols shown in the drawings, 1......Support substrate 2......a-3iN:H layer (blocking layer) 3... ...a-8iC:H layer (charge transport layer)4...Inorganic material layer (surface modification layer)A-5iN:H layer (light conductive layer or photosensitive layer). Agent Patent Attorney Hiroshi Aisaka Figure 1 Figure 3 Figure 4 a-5i+ -xNx:H Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 3 Figure 10

Claims (1)

[Scope of Claims] 1. A substrate, and a thickness of 2 to 300 ml of nitrogen atom-containing amorphous hydrogenated and/or fluorinated silicomorphous hydrogenated and/or fluorinated silicon carbide formed on the substrate.
80 ρ charge transport layer, a 0.3 to 5 μm thick photoconductive layer made of nitrogen atom-containing amorphous hydrogenated and/or fluorinated silicon formed on the charge transport layer, and a photoconductive layer formed on the photoconductive layer. 100mm thick made of inorganic material
A recording medium comprising a surface modified layer of ~5000. 2. The nitrogen atom content of the photoconductive layer is 1 to 30 atomic
%, the nitrogen atom content of the charge blocking layer is 5 to 50a
tomic %, the carbon atom content of the charge transport layer is 5~
9Q atomic 96, the recording medium according to claim 1. 3. The nitrogen atom content of the photoconductive layer is 15 to 25 atoms
ic%, the nitrogen atom content of the charge blocking layer is 10~
40 atomic 96, the recording medium according to claim 2, wherein the charge transport layer has a carbon atom content of 10 to 50 atomic%. 4. The specific resistance of the photoconductive layer is 1010 Ω-α or more due to doping with a group mA element of the periodic table, and the charge blocking layer is P-type or N-type due to doping with a group mA element of the periodic table. The recording medium according to any one of claims 1 to 3, which indicates the conductivity type of the type. 5. The recording medium according to claim 4, wherein the photoconductive layer has a specific resistance of 10'2 Ω-α or more due to doping with an element of group 111A of the periodic table. 6. The recording medium according to any one of claims 1 to 5, wherein the surface-modified layer has a specific resistance of 10'3 Ω-α or more. 7. The surface modified layer is SiO, StO2, Al2O5,
MgO. ZnO1PbO, Cab, BedS Bad, ZrO2
, Tt Ot , Ta 20 y, CeO2, SnO2
A recording medium according to any one of claims 1 to 6, which is formed of at least one member selected from the group consisting of: 8. The thickness of the photoconductive layer is 0.5 to 3 μm, the thickness of the charge blocking layer is 400 to 5oooL, the thickness of the charge transport layer is 5
~30μm1 The thickness of the surface modified layer is 400~20001
Any one of claims 1 to 4, which is
Records listed in section.