JPH01185639A - Photosensitive body - Google Patents

Abstract

PURPOSE:To make possible to maintain the good image of the title body even at the time of repetitive use by laminating an electric charge generating layer composed of a hydrogenated and/or a halogenated amorphous silicone, an electric charge transfer layer and a surface deforming layer which contains carbon atom and satisfies a specified condition, on a substrate. CONSTITUTION:The photosensitive body 39 is formed by laminating an electric charge blocking layer 44 composed of a-Si, the electric charge transfer layer 42 composed of a-SiC:H, the electric charge generating layer 43 composed of a-Si:H and the surface reforming layer 45 composed of the hydrogenated amorphous silicone contg. carbon and oxygen atoms and at least carbon atom, on a drum shaped conductive supporting substrate 41 composed of Al, etc. As the layer 45 contains the carbon atom, the mechanical strength of the photosensitive body is improved, and the image trailing of the body is prevented, without increasing the dark decay and deteriorating the photosensitivity by controlling the specific resistivity rhoD of the body at a dark place to that rhoL at the time of radiation of light so as to satisfy the condition 1 by changing the amount of carbon, hydrogen or halogen atom in the layer 45.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a photoreceptor, such as an electrophotographic photoreceptor.

Conventional technology Conventionally, amorphous silicon (
Electrophotographic photoreceptors using a-3t) as a matrix have been proposed in recent years.

Since a-3i has so-called dangling bonds, amorphous hydrogenated silicon (a-3i: H ) has been proposed.

However, photoreceptors with a-3i:H surfaces are susceptible to surface chemical stability, such as the effects of long-term exposure to the atmosphere or moisture, and the effects of chemical species generated by corona discharge. , has not been sufficiently investigated so far. For example, items that have been left for more than a month will be affected by moisture.
It is known that the receptor potential is significantly reduced. On the other hand, amorphous hydrogenated silicon carbide (hereinafter a-3iC:H
It is called. ), its manufacturing method and existence” Ph11
．． Mag, Vol. 35'' (1978), etc., and its characteristics include high heat resistance and surface hardness, and high dark resistivity (compared to a-3i:H).
It is known that the optical energy gap varies over a range of 1.6 to 2.8 eV depending on the amount of carbon.

However, there is a drawback that the long wavelength sensitivity becomes poor due to the widening of the band gap due to the inclusion of carbon.

An electrophotographic photoreceptor combining such a-3iC:H and a-3i:)l has been proposed, for example, in Japanese Patent Application Laid-Open No. 115559/1983. According to this, a-3i:
An a-3iC:8 layer is formed as a surface modification layer on a charge generation layer consisting of I(I).

However, when the present inventor investigated the above-mentioned known photoreceptor, it was found that even if a surface modification layer was provided, it was still not as effective as expected (in particular, image deletion was likely to occur).

C.9 Purpose of the Invention An object of the present invention is to provide a photoreceptor that can withstand repeated use and can produce good images.

21 Structure of the invention and its effects, that is, the present invention comprises a charge generation layer made of amorphous hydrogenated and/or halogenated silicon, a charge transport layer made of amorphous hydrogenated and/or halogenated silicon carbide, and a carbon atom. and a surface modified layer made of amorphous hydrogenated and/or halogenated silicon containing at least carbon atoms among oxygen atoms, and this surface modified layer has 9o≧1011Ω-cm and 0.01≦l). L/f
)o≦1.0 (where ρ is the specific resistance in a dark place, and ρD is the specific resistance when irradiated with light).

According to the present invention, since the surface modified layer contains at least carbon atoms of carbon atoms and oxygen atoms, the mechanical strength of the layer is increased, and there is no deterioration of image quality due to white streaks, etc.
Excellent printing durability.

Moreover, as a condition for the specific resistance of the surface modified layer, ρ. ≧10
By sufficiently increasing the dark specific resistance of 11Ω-cI11, the dark attenuation of the charge as a photoreceptor is significantly reduced, and image blurring during image formation is greatly reduced, and ρL/ρ. 0
．． It is set at O1 to 1.0 to improve light sensitivity as well as resistance to image deletion. That is, ρ. is 1011Ω-0111
If it is less than ρL/ρD, the charge decay will be severe, and ρL/ρD
Even if ρD is less than 0.01, ρD is too small and this is also inappropriate for image deletion resistance.

In addition, since the above charge generation layer and the above charge transport layer are provided to form a functionally separated laminated structure, the charge generation layer provides photosensitivity in a wide wavelength range, and the charge generation layer and the heterojunction The charge transporting layer forming the charge transporting layer can improve the charge transporting ability and the charging potential.

E, Example Hereinafter, the present invention will be described in detail with reference to examples.

FIG. 1 shows an a-3i electrophotographic photoreceptor 3 according to this embodiment.
9. This photoreceptor 39 is provided on a drum-shaped conductive support substrate 41 such as a substrate 41 as required.
-3i-based charge blocking layer 44; charge transport layer 42 made of amorphous hydrogenated silicon carbide (a-3iC:H); charge generation layer 43 made of a-5i:H;
A surface modified Li layer 4 made of hydrogenated amorphous silicon (or a-3iC:H) containing at least C and O
It has a structure in which 5 and 5 are laminated. The charge blocking layer 44 is a-3i:Hla-3iC:H or a-
It may be composed of S i N :H, and may be doped with an element of group IA or group VA of the periodic table.

Further, the charge transport layer 42 and the charge generation layer 43 may also be doped with similar impurities. The charge generation layer 43 has a dark resistivity ρ. The ratio of the resistivity ρD at the time of light irradiation is sufficiently large as an electrophotographic photoreceptor (the photosensitivity (particularly to light in the visible and infrared regions) is good.The above layer 43-4
An intermediate layer such as a-3iC may be provided between the layers 5 and 5.

What should be noted here is that the surface modified layer 45 contains at least C of C10: a-S i C: H or a-
3i (Co):H.

This improves the mechanical strength of the surface modified layer 45. Regarding the composition of the surface modified layer 45, 10 atm%≦(
C) or (C+O)≦100a tm% (however, (S
i) + (C) = 1100at% or (S
i) + (C) ten (0) =
1100atm%), and 40a Lm%≦(C) or (C+O)≦70atm%
It is more preferable to use (here, atm % represents the percentage of the number of atoms). If the content of C or C+0 is too small or too large, the effect of improving scratch resistance will be poor.

In addition, another noteworthy point of this photoreceptor is that the surface modification layer 45 has a
I, (specific resistance in the dark) and ρL (specific resistance when illuminated with light)
Regarding, ρ0≧1011Ω−■ (preferably ρD≧1QIZΩ−an) 0.01≦ρL
/ρ0≦1.0 (preferably 0.1≦ρL/ρ.≦1.0, more preferably 0.5≦ρL/ρ.≦1.0). In other words, ρD is smaller than 1011Ω−(,
ρL/ρ. If the value is smaller than 0.01, charge retention becomes extremely insufficient, resulting in severe image deletion. In addition, ρ. and ρL/ρゎ can be controlled by the amount of carbon, hydrogen or halogen in the surface modification layer.

Further, the thickness of the surface modified layer 45 is preferably 200 to 30,000 layers, and more preferably 1,000 to 10,000 layers. If the film thickness is too large, the residual potential V becomes too high and the photosensitivity decreases, resulting in a-3i
It is easy to lose good properties as a photoreceptor, and if the film thickness is too small, charges will not be charged on the surface due to tunneling effect, resulting in increased dark decay and decreased photosensitivity.

The charge generation layer 43 may be composed of a-3i:H, and its composition is preferably 5 to 40 atm% of U, and when containing halogen in place of or in combination with H, 5 to 40 atm% of halogen. tm% or the total amount of H and halogen is preferably 5 to 40aLm%. This charge generation layer 43 is preferably doped with an impurity, particularly an element of group 1t [A or VA of the periodic table] in order to improve charging performance. For example, during glow discharge (described later), (Bz Hb) / (S i Ha ) ~10-
'~100 (preferably 104-10) capacity ppm, (
P Hs ) / (S i H4) ~10-3~
The volume may be 100 (preferably 10 -2 to 10) ppm.

Further, the thickness of this layer 43 is 1 to 50 μm, preferably 5 μm.
It is preferable to set the thickness to 30 μm. If the thickness of the layer 43 is too small, a sufficient charging potential cannot be obtained, and if it is too large, the residual potential increases, which is insufficient for practical use.

The charge transport layer 42 has both a potential holding function and a charge transport function, and preferably has a dark resistivity of 10 12 Ω or more.
It has high electric field resistance, holds a high potential per unit film thickness, and efficiently transports electrons to the support 1 side with high mobility and long life.

Furthermore, since the size of the energy gap can be adjusted by adjusting the carbon content (especially 5 to 30a Lm%), it is possible to efficiently inject electrons generated in response to light irradiation in the charge generation layer 43 without creating a barrier. Can be done.

Therefore, this a-3iC:H layer 42 maintains a high surface potential at a practical level, and efficiently and quickly transports the charge carriers generated in the a-3i sH layer 43, resulting in a photoreceptor with high sensitivity and no residual potential. There is work.

The carbon atom content of this charge transport layer 42 is set to 5 to 30 atm.
% (even 10 to 20 atm%) (however,
The total number of atoms of Si and C is 100atm%).

That is, the carbon atom content is 5. Below atm%, a-3
The specific resistance of iC:H layer 2 is 1012Ω, which is necessary for potential holding ability.
In particular, the charging potential tends to be insufficient because it falls below the - mark.

Moreover, when the carbon atom content exceeds 30a tm%, the specific resistance also decreases, and at the same time, there are too many carbon atoms and a
-3 Defects in the iCsH layer increase and the carrier transport ability itself deteriorates (easily).

This layer 42 preferably contains 5 to 50 atm% of hydrogen atoms, and when containing halogen in place of or in combination with H, 5 to 50 atm% of halogen, or the total amount of H and halogen. is preferably 5 to 50a tn+%. This layer 42 is preferably doped with an impurity, particularly an element of group 111A or VA of the periodic table, to improve charging performance. For example, during glow discharge (described later), (Bz H
h ) / (S i H4) ~10-
3 to 1000 (preferably 10-” to 10”) capacity ppm, (P Ha )/(S i Ha
) = 10-3 to 1000 (preferably 10-"
~10z) The volume may be ffipppm.

Further, the thickness of the charge transport layer 42 is, for example, 5 μm to 30 μm in order to apply a dry development method using the Carlson method.
It is desirable that it is μm. If this film thickness is less than 5 μm, it is too thin and the surface potential necessary for development cannot be obtained.
Moreover, if it exceeds 30 μm, the rate of carrier reaching the support 41 will decrease.

Further, in order to sufficiently prevent electron injection from the substrate 41 and improve sensitivity and charging ability, the charge blocking layer 44 is doped with an element of Group IIA of the periodic table (for example, boron) by glow discharge decomposition. , transforms into P type (and even P-type).

It is desirable to control the doping amount as follows depending on the composition of the blocking layer.

a-3i:H (H content 5 to 40 atm%): (Bz
Hl, "J / (S i H4] = 10-' ~ 1
04 Capacity ppm (and 10-' to 10" Capacity ppm ugly) (P Hl ) / (S iH4) = 10-"
~10' volume 1 ppm (furthermore 10-'~10' volume ppm
m) a-3iC:H (H content 5-50at111%,
C content 5-100at%): (Bz Hb) / (S i H4) = 10-'
~10' volume 1 ppm (furthermore 10-1~104 volume ppm
m) (P Hs ) / (S i H4) = 10
-3~10&volume ppm (furthermore, 10~1~104 volume pl) m) a-3iN:H (H content 5~50 atm%
, N content 15 to 60 atm %); (B! H,) / (S i H4] = 10-” to 1
06 capacity ppm (even 10-1 to 104 capacity ppm)
(P Hl ) / (S i H-) = 10-3
~b (moreover, 10-' to 10' capacitance ppm) Further, the thickness of the blocking layer 44 is preferably 100 to 2 μm. If the thickness is too small, the blocking effect will be weak, and if the thickness is too large, the charge transport ability will tend to deteriorate.

Note that each of the above layers needs to contain hydrogen.

In particular, the hydrogen content in the charge generation layer 43 is necessary to compensate for dangling bonds and improve photoconductivity and charge retention.

Also, the order of the layers 42, 43 described above may be reversed. In addition to boron, the impurities to be doped include A2,
Elements from group II of the periodic table [A] such as GaX InXTffi can be used, and elements from group VA of the periodic table such as As and sb can also be used in addition to phosphorus.

Next, a method for manufacturing the above-mentioned luminescent body (for example, drum-shaped) and an apparatus therefor (glow discharge apparatus) will be explained with reference to FIG.

A drum-shaped substrate 41 is set rotatably vertically in a vacuum chamber 52 of this device 51, and a heater 55 is used to rotate the substrate 41.
can be heated to a predetermined temperature from the inside. A cylindrical high frequency electrode 57 with a gas outlet 53 is disposed around and facing the substrate 41, and a glow discharge is generated between the electrode 57 and the substrate 41 by a high frequency power source 56. In addition, 62 in the figure is a supply source of SiH4 or a gaseous silicon compound, 63 is a supply source of hydrocarbon gas such as CH, and 64 is a supply source of N2.
65 is a supply source of oxygen compound gas such as 0□, 66 is a carrier gas supply source such as Ar,
67 is an impurity gas (for example, B2H4) supply source, and 68 is each flow meter. In this glow discharge device, first, the surface of a support, for example, an Al substrate 410, is cleaned and then placed in a vacuum chamber 52, and the gas pressure in the vacuum chamber 52 is increased to 10-''.
The substrate 41 is evacuated and adjusted so that the
at a predetermined temperature, especially 100 to 350°C (preferably 150°C)
-300°C). Next, using a high-purity inert gas as a carrier gas, SiH4 or a gaseous silicon compound, CH4, NZ, COX, 0□, etc. are suitably heated in a vacuum W! 52, and a high frequency voltage (for example, 1
3.56 Mllz). As a result, each of the above reaction gases is decomposed by glow discharge between the electrode 57 and the substrate 41, and a-SiC:Hla-3iC:H, a-3i:
H,, a-3iC:H above layer 44.42.43.4
5 in succession (i.e., corresponding to the example of FIG. 1, for example).

In the above manufacturing method, the support temperature is set at 100 to 350"C in the step of forming the a-3i layer on the support, so that the film quality (especially electrical properties) of the photoreceptor can be improved. Can be done.

In addition, when forming each layer of the above a-3i photoreceptor,
In order to compensate for dangling bonds, it is necessary to use halogens such as fluorine instead of H, or in combination with H.
i F4 etc., a-3i :F, a-3t
:H:F, a-3iN:F.

a-3iN:H:F, a-3iC:F.

It can also be a-3iC:H:F or the like.

The above manufacturing method is based on the glow discharge decomposition method, but other methods include the sputtering method, the ion blating method, and the method of evaporating Si while introducing activated or ionized hydrogen in a hydrogen discharge tube. (In particular, Japanese Patent Application Laid-Open No. 56-78413 (Patent Application No. 54-1524) filed by the present applicant)
The above photoreceptor can also be manufactured by the method of No. 55).

Hereinafter, the present invention will be described with reference to specific examples.

By glow discharge decomposition method, the first
An electrophotographic photoreceptor having the structure shown in the figure was manufactured.

That is, first, after cleaning the surface of a support, for example, a drum-shaped Al substrate 41 having a smooth surface, it is placed in a vacuum chamber 52 in FIG. 2, and the gas pressure in the vacuum chamber 52 is set to 10-'
Torr, and the substrate 41 is heated to a predetermined temperature, particularly 100 to 350°C (preferably 150°C).
-300°C).

Then, high-purity Ar gas was introduced as a carrier gas and the frequency was 13.56 M under a back pressure of 0.5 Torr.
A high frequency power of Hz was applied and preliminary discharge was performed for 10 minutes. Next, a reaction gas consisting of SiH and BzHb was introduced at a flow rate ratio of 1:1:(1,5Xl0-').
By glow discharge decomposition of the (A r+ S i H4 + Bz Ha )/combined gas, the P-type a-3iC:H layer 44, which plays a charge blocking function, is reduced to 6 μm/
A film was formed to a predetermined thickness at a deposition rate of hr. Then 5I
The flow rate ratio of B, H, to H4 is 1: (6X10-')
The charge transport layer 42 was sequentially formed to a predetermined thickness at a deposition rate of 6 μm/hr. Subsequently, the supply of B, H, and CH is stopped, SiH is decomposed by discharge, and a-3 of a predetermined thickness is formed.
i: H layer 43 was formed. Furthermore, the flow rate ratio is 40:3:90
(Ar:5tHa:CH4) rR mixture gas at reaction pressure P = 0.5 Torr.

Glow discharge decomposition is performed at a discharge power Rf = 400W to form an intermediate layer of a predetermined thickness, and a flow rate ratio of 40:3:90 (
A r : S i H4 : CHa ) mixed gas at reaction pressure P = 1. OTorr % discharge power Rt =
A surface protective layer 45 was further provided by glow discharge decomposition at 400 W, and an electrophotographic photoreceptor was completed. At this time, the supplied C
ρ of the surface layer 45 by appropriately controlling the amount of H, the reaction pressure, and the power of R. , ρD was varied variously.

Note that when the surface layer 45 was made of a-3i Co, CO2 was used as the oxygen source.

Next, the following tests were conducted using each of the above photoreceptors.

After acclimatizing the photoreceptor in a modified electrophotographic copying machine U-B 1x2500 (manufactured by Konica Corporation) for 24 hours in an environment with a temperature of 33°C and a relative humidity of 80%, the developer, paper, and blade were removed. After 1000 copies were made without contact with the paper, an image was printed and the degree of image blurring was determined based on the following criteria.

◎There is no image blurring at all, and the reproducibility of 5.5-point alphabetic characters and thin lines is good.

○: 5.5 point alphabetic characters are slightly thicker.

△: 5.5 point letters are crushed and difficult to read.

X: 5.5 points of unreadable letters.

Sensitivity (halved El/□) Using the above device, the long wavelength component of 620 nm or more of the image exposure wavelength was sharply cut using a guichroic mirror (manufactured by Koshinko Co., Ltd.), and the surface potential was changed from 500 to 250.
The amount of exposure required to reduce the amount by half to V.

(The exposure amount was measured using a 550-1 photometer (manufactured by EC'andG)) The results are summarized in Table 1 below. From this result, when photoreceptors (Nll-3, 5 to 12) were prepared according to the present invention, electrophotographic photoreceptors with significantly less image deletion and good photosensitivity were obtained.

Table-1 In addition, the above ρ9, ρD/ρ. As shown in Figure 3,
It has been found that it varies with the optical bandgap (Eg, opt) of layer 45, in other words with the carbon or hydrogen content.

Therefore, ρD≧101Ω-cm, ρL/f)n =
To satisfy 0.01 to 1.0, Eg and opt must be approximately 2
．． It turns out that it should be 1 eV or more.

Next, as a result of experiments, it was found that the functionally separated photoreceptor according to the present invention also has excellent charging characteristics.

The measurements were performed as follows, and the results are shown in Table 2 below.

Stay! Standing V, I(v) U-B 1x1600 Modified machine (manufactured by Konica ■) was used to measure the potential, and the static elimination light 3012 had a peak at 400 nm.
The surface potential of the photoreceptor that remains even after irradiation with ux/sec.

Book 9 Stand■. (V) Using a modified U B 1x1600 machine (manufactured by Konica ■),
Photoconductor inflow current 150μA, 36 under no exposure condition
Surface potential just before development measured with a 0SX type electrometer (manufactured by Toresok).

Using the above device, a dichroic mirror (manufactured by Koshinko Co., Ltd.) sharply cuts long wavelength components of 620 nm or more of the image exposure wavelength, and the surface potential is adjusted from 500 V to 250 V.
■The amount of exposure required to reduce the amount of light by half.

(The exposure amount was measured with a 550-1 light meter (manufactured by EGandG)) Table 2 However, in each data in the above table, the left side (*1) is the function-separated photoreceptor based on the following invention, the right side is (*2) indicates the data of the following single-layer photoreceptor.

*l) Support: Al, blocking layer: 1 μm thick boron-doped a-3iC:H.

Charge transport layer: 12 μm thick boron-doped a-3iC
:H, charge generation layer: 7 μm thick boron-doped A-3
i: H1 surface modified layer: thickness 0.3. um's a-3iC:
) (*2) Support: Al, blocking layer: 1 μm thick
boron-doped a-3iC:H.

Photoconductive layer: 19 μm thick boron-doped a-3i:
H1 surface modified layer: a-3iC:H with a thickness of 0.3 pm

[Brief explanation of the drawing]

1 to 3 show examples of the present invention, in which FIG. 1 is a sectional view of an a-3i photoreceptor, FIG. 2 is a schematic sectional view of a glow discharge device, and FIG. 3 is a schematic sectional view of a glow discharge device. is a graph showing the relationship between optical bandgap and specific resistance. In addition, in the symbols shown in the drawings, 39...a-3i photoreceptor 41...support (substrate) 42...charge transport layer 43...charge generation layer 44... ...Charge blocking layer 45...Surface modification layer. Agent Patent Attorney Hiroshi Aisaka

Claims (1)

[Scope of Claims] 1. A charge generation layer made of amorphous hydrogenated and/or halogenated silicon, a charge transport layer made of amorphous hydrogenated and/or halogenated silicon carbide, and at least one carbon atom among carbon atoms and oxygen atoms. a surface modified layer made of amorphous hydrogenated and/or halogenated silicon containing atoms, and this surface modified layer has ρ_D≧10^1^1Ω-cm and 0.01≦ρ_L/
ρ_D≦1.0 (however, ρ_D is the specific resistance in the dark, ρ_
L is the specific resistance at the time of light irradiation. ) A photoreceptor that satisfies the following conditions.