JPS5967543A - 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 electrostatic charge blocking 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 an inorg. material is formed on a backing substrate 1. A photoconductive layer 3 of 2-80mum thickness consisting of nitrogen atom-contg. amorphous hydrogenated and/or fluorinated silicon is formed on the layer 2. A surface reforming layer 4 of 100-5,000Angstrom consisting of amorphous hydrogenated and/or fluorinated silicon carbide layer is further formed on the layer 3. Since the layer 3 is formed of nitrogen-contg. a-Si in the above-mentioned way, said layer exhibits excellent sensitivity to 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 doping impurities.

Description

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

Conventionally, electrophotographic photoreceptors were made of 88% Se or As.

Photoreceptors doped with Te, Sb, etc., photoreceptors in which ZnO+CdS is dispersed in a resin binder, and the like 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-8i) as a base material have been proposed in recent years.

a-8i has a so-called dangling bond in which the bond of 5i-8i 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 photoconductive carriers are trapped in a localized level, resulting in poor photoconductivity. Therefore, the dangling bonds are filled by compensating the above defects with hydrogen atoms (H) and bonding H to Si.
It is called St 2H. ) has a resistivity of 10” to 1 in the dark.
0"Ω-α, which is about 1/10,000 times lower than that of amorphous Se. Therefore, a photoreceptor made of a single layer of a-Si:H has a high dark decay rate of the surface potential, and the initial charging potential The problem is that the amount 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-Si:H, the resistivity can be increased to about 1012 Ω-α by doping with boron, but the amount of boron cannot be precisely controlled in this way. It is not easy, and
Even with a resistivity of about 1012 Ω-α, the photosensitivity is insufficient for use in a photosensitive process using the Carlson method, and the charge retention properties are still insufficient. Furthermore, by introducing a small amount of oxygen together with boron, it is possible to increase the resistance to about 1 oil Ω-m, but when this is used in a photoreceptor, the photoconductivity decreases, worsening of edge breakage and residual potential. The problem arises that

In addition, photoreceptors with a-8t: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, 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-8i
:H has poor film adhesion (adhesion) to a support such as Al or stainless steel, which poses a problem in practical use as an electrophotographic photoreceptor. As a countermeasure to this problem, Japanese Patent Application Laid-Open No. 55-87154
Silane coupling agent as in JP-A-56-7
No. 4257, an adhesive layer made of an organic polymer compound such as polyimide resin or triazine resin is
: It is known to be provided between the H layer and the support.

However, in these cases, the formation of the adhesive layer and a-8
It is necessary to perform the film formation of the i:H layer by a different method, and therefore a new film forming apparatus must be used, resulting in poor workability.

Moreover, in order to make the a-Si:H layer have good photoconductivity, the temperature of the substrate (support body) during film formation must be adjusted to about 20%.
It is necessary to maintain the temperature at 00°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-8i:H (hereinafter sometimes referred to as a-8iN:H), in which nitrogen atoms are contained in a-8i: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-SiN:
The H layer can be increased in dark specific resistance to about I x 10" Ω by doping with boron, and also has excellent photoconductivity (sensitivity). However, according to the inventor's study, , in the above-mentioned known photoreceptor, a
It was found that unnecessary charge was easily injected into the -SiN:H layer from the conductive support, and the adhesion between the a-SiN:H layer and the support was also insufficient.

Furthermore, there are examples in which a surface coating layer is provided on the a-SiN:H layer, but since the surface coating layer is simply made of synthetic resin, it has poor printing durability, heat resistance, and durability during repeated use. It was also found that the stability of electrophotographic properties, chemical stability of the surface, mechanical strength, etc. were not sufficient. Moreover, since the above-mentioned surface coating layer easily absorbs or reflects light that should be incident on the a-8iN:H layer, it also has the disadvantage of reducing photosensitivity.

The present invention was made in order to correct the above-mentioned defects, and consists of a base (for example, a conductive support such as A1) and an inorganic material (for example, 5 in 2) formed on this base. A charge blocking layer of X ~ 1 μm and a nitrogen atom-containing amorphous hydrogenated and/or fluorinated silicon (e.g. a
-8iN:H) with a thickness of 2 to 80 pm and amorphous hydrogenated and/or fluorinated silicon carbide (e.g. a-8iC:H) formed on the photoconductive layer.
The present invention relates to a recording medium characterized by comprising a surface modified layer having a thickness of 100 to 5000 Å.

According to the present invention, since the photoconductive layer is formed of nitrogen-containing a-8i, 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.
ρ of 100-m or more. Therefore, the photoconductive layer has excellent photosensitivity and potential holding ability.

Moreover, since a blocking layer made of an inorganic material is provided under this photoconductive 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. Furthermore, an a-SiC layer is provided as a surface modification layer on the photoconductive layer;
-SiC has high heat resistance and surface hardness, and functions as a window material that can effectively transmit light in the visible and infrared regions depending on the amount of carbon. This significantly improves printing durability, heat resistance, photosensitivity, stability of electrophotographic properties during repeated use, chemical stability of the photoreceptor surface, mechanical strength, prevention of changes over time during storage, etc. be able to.

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

The photoreceptor in FIG. 1 has a conductive support substrate 1 such as A1,
A charge blocking layer 2 made of an inorganic substance (for example, 5iOz), a photoconductive layer 3 made of a-8iN:H, and a-8
It has a structure in which surface modified layers 4 made of iC:H are sequentially laminated.

In particular, the photoconductive layer 3 has a nitrogen atom content of 1 to 3° atoms.
As shown in FIG. 2, the dark resistivity pD
The ratio of resistivity ρ1 at the time of light irradiation is sufficient, and the photosensitivity (
Particularly good against light in the visible and infrared regions). In addition, a Group IIA element of the periodic table, for example, boron, is added at a flow rate ratio (BzHs / 5iH4) = 1 to 500, which will be described later.
By doping with ppm, as shown in Fig. 3,
Increase the specific resistance to 10100-m or more (even 1o12Ω-m)
above), it can be seen that high resistance can be achieved. 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 broken line in Figure 3 shows the resistance change due to impurity doping to a-8i:H, but the degree of increase in resistance is insufficient for a-8t:H, and it is still 1o10Ω. A stable high resistance value can only be obtained at around −α. Further, as understood from FIG. 2, in a-SiN:H, ρ can be controlled by the amount of nitrogen, and in combination with impurity doping, the range of resistance control can be widened. As shown in FIG. 4, the photoconductive layer 3 has an optical energy gap (approximately 1.0 mm in the case of a-8i:H) as the nitrogen content increases.
65 eV), it is possible to control the absorption characteristics of the incident light.

It is desirable that the blocking layer 2 has a specific resistance of 10 13 Ω-m or more in order to improve the surface potential retention ability. Usable construction materials are 5io1Sto2, A
l10s, MgO, ZnO, Pb0XCab, Be
d. Bad.

Zr 02, TiO2, Tag's, CeCh, 5nO
At least one selected from the group consisting of z is mentioned.

Further, regarding the surface modified layer 4, the carbon atom content is set to 40 to 90 atoms (preferably 40 to 70 atoms).
If it is an atomic material, as shown in FIG. 5, the optical energy gap will be widened to 2.4e or more, and it will easily transmit relatively long wavelength light, making it a window material for visible and infrared light.

The thickness of each layer of the photoreceptor described above also has an appropriate range, and the photoconductive layer 3 has a thickness of 2 to 80 μm (preferably 5 to 30 μm).
m), blocking layer 2 has a thickness of 100 X to 1 μm (preferably 400 to 5 oooX), surface number II layer 4 id 1
00~5000A (preferably 400~2000X
). If the thickness of the photoconductive layer 3 is less than 2 μm, the charging potential will not be sufficient, and if it exceeds 80 μm, it will be unsuitable for practical use and it will take time to form the film. If the blocking layer 2 has a thickness of less than 100 A, there will be no blocking effect, and if it exceeds 1 μm, the charge transport ability will be poor. Moreover, if the surface modification layer 4 is less than 1ooX, it will not be effective, and if it exceeds 500OA, the photosensitivity will decrease, residual potential will increase, etc., which will be inappropriate.

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 bonds and improve photoconductivity and charge retention, and is usually 1 to 40 atoms.
C%, preferably 3.5 to 20 atomic%. In addition to boron, kl, Ga, In, and T1 are also used as impurities to be doped into the photoconductive layer 3.
Group 111A elements of the periodic table can be used.

In addition, in order to compensate for dangling bonds, fluorine can be introduced in place of the above-mentioned H or in combination with H.
-3iN:FXa-8iN:H:FXa-8iC:F.

It can also be a-8iC:H:F. In this case, the amount of fluorine is preferably from o, oi to 20 atomic %, and more preferably from 0.5 to 1° atomic %.

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, the season in the diagram,
21.22, Gen, Sae, 25.27, Nephew, 29, Ka, 31
．． 37, 38, 40 are respective valves, 32 is a source of SiH4 or gaseous silicon compound, 33 is a source of nitrogen such as NH3 or N2, 34 is a source of hydrocarbon gas such as CH4, 35 is a static or Carrier gas supply source such as H3, 36
is an impurity gas (eg, Bias) source. In this glow discharge device, first, a support such as Al
After cleaning the surface of the substrate l, it is placed in a vacuum chamber 12,
The valve 37 is adjusted and evacuated so that the gas pressure in the vacuum chamber 12 becomes 10-6 Torr, and the substrate 1 is kept at a predetermined temperature.
For example, it is heated and maintained at 30 to 400°C. Next, using a high-purity inert gas as a carrier gas, SiH4 or a gaseous silicon compound, a mixed gas prepared by diluting an appropriate amount of NH3 or N2, and CH-, BzHa, etc. are appropriately introduced into the vacuum chamber 12, for example, 0. A high frequency voltage (for example, 13.0 Torr) is applied by the high frequency power supply 16 under a reaction pressure of .01 to 10 Torr.
56 MHz) is applied.

As a result, each of the above reaction gases is decomposed by glow discharge, and hydrogen-containing a-8iN:H and a-8iC:H are removed from the layer 3.
．． 4 and sequentially deposited on the substrate. At this time, by appropriately adjusting the flow rate ratio of the silicon compound and the nitrogen compound or carbon compound and the substrate temperature, a-8ix-xNx having the desired composition ratio and optical energy gap:
H, a-8it-yCy: H can be precipitated,
In addition, it is possible to deposit the blocking layer 2 at a rate of 1000X/min or more without significantly affecting the electrical properties of the deposited film. It is possible.

In the case of the sputtering method, a thin film of 5 iOz may be formed by using a target of, for example, 5 to 2, introducing a sputtering gas such as M gas into the deposited layer, and performing sputtering.

The pressure of the k atmosphere may be within any range as long as glow discharge can be maintained, and is generally 0.01 to 1.0 Torr.
In order to obtain stable discharge, it is desirable that the pressure is 01 to 1.0 Torr. Inorganic substance/asi according to the invention
Photoreceptors with a basic structure of N:H/a-SiC:H, especially a-8iN:H and a-3iC:H, can be manufactured in sequence using the same equipment by simply changing the type and flow rate of the reaction gas used. It can be created by coating.

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. 54-152) filed by the present applicant)
The above photoreceptor can also be manufactured by the method of No. 455). In addition to SiH4, the reaction gas used is 5
Lower hydrocarbon gases such as i2Ha, 5IF4.5tHFs, or derivative gases thereof, C2H other than CHa, and Cs Hn can be used.

FIG. 7 shows a photoreceptor according to the present invention in the above-mentioned Japanese Patent Application Laid-Open No.
This figure shows a vapor deposition apparatus used for forming υ 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, and the inside of the Pel jar 41 is thereby pumped, for example, from 1o-3 to 10
The substrate 1 is placed inside the Pel jar 41 and heated to a high temperature 1 by the heater 45.
50 to 5oo0C1, preferably heated to 250 to 45o0C, and applying a negative DC voltage of 0 to -1°KV, preferably -1 to -6KV to the DC power source 46, the outlet facing the substrate 1. While introducing active hydrogen and hydrogen ions from a hydrogen gas discharge tube 47 with an outlet connected to the Pelger 41 into the Pelger 41, a silicon evaporation source 48 provided facing the substrate 1 and, if necessary, While heating the aluminum evaporation source 49, each upper shutter S is opened to simultaneously evaporate silicon and aluminum at an evaporation rate such that the evaporation rate ratio is, for example, 1:10', and to activate the silicon and aluminum into the Pel jar 41 by the discharge tube 5o. NH3 gas or CH4 gas containing a predetermined amount of aluminum if necessary.
-8iN: H layer 3, a-8iC: H layer 4 (see Figure 1)
form.

For example, the structure of the discharge tube 47, 50 is shown in FIG. 8, as shown in FIG. , a discharge space member 64 made of, for example, cylindrical glass surrounding the discharge space 63, and another ring-shaped electrode member 66 provided at the other end of the discharge space member 64 and having an outlet 65.
Then, by applying a DC or AC voltage between the one electrode member 62 and the other electrode member 66, for example, hydrogen gas supplied via the gas port 61 is discharged in the discharge space 63. A glow discharge is generated, whereby active hydrogen composed of hydrogen atoms or molecules activated by electron energy and ionized hydrogen ions are discharged from the outlet 65.
more excreted. The discharge space member 64 in this illustrated example has a double pipe structure and is configured to allow cooling water to flow therethrough, and 67 and 68 indicate a cooling water inlet and an outlet.

69 is a cooling fin for one electrode member 62.

The distance between the electrodes in the hydrogen gas discharge tube 47 is 10~
The voltage is 1stM, the applied voltage is 600V, and the pressure in the discharge space 63 is about 10'' Torr.

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

The Aj substrate, which had been cleaned with trichlorethylene and etched with 0.1% NaOH aqueous solution and 0.1% HNOs aqueous solution to form a 5ift layer on the surface, was set in the glow discharge device shown in Fig. 6, and the inside of the reaction tank was heated for 10 minutes. After evacuating to a high vacuum level on a Torr stand and heating the support to 200'C, high purity Ar gas was introduced, and under a back pressure of 0.5 Torr, the frequency was 13.56 MHz and the power density was 0. .04W
/ crn” high frequency power was applied, and preliminary discharge was performed for 15 minutes.

The blocking layer 2 can be formed by, for example, a sputtering method, a vacuum evaporation method, or the like. In the case of a sputtering method, a thin film made of Si may be formed by using a target made of, for example, Si 2 O=, 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 in the range of 001 to 1. OTorr%
In order to obtain stable discharge, the ratio should be 0.1 to 1. Preferably, it is OTorr. A reaction gas consisting of 5iHa and CH4 is introduced into the surface modification layer to form (Ar + SiH4 + CH
4) Formed by glow discharge decomposition of mixed gas.

Ta. In forming the photoconductive layer, SiH4, N2, and, if necessary, B and H were subjected to discharge decomposition to form an a-8iN:H photosensitive layer.

The electrophotographic photoreceptor thus prepared was mounted on an electrometer model 5P-428 (manufactured by Kawaguchi Electric Co., Ltd.).
The electric power applied to the discharge electrode of the charger was set to 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 set to V6 (V). Reduce irradiation light amount by half Exposure amount EX/2
(ltlx-8ec).

Although the light attenuation curve of the surface potential is flat at a certain finite potential, it may not become completely zero, and this potential is called a residual potential VR (V). Also, regarding image quality,
A photoreceptor was made into a drum shape, and an electrophotographic copying machine U-BixV (manufactured by Konishiroku Photo Industry Co., Ltd.) was used at 2°0C and 160%RH.
The initial image quality (1,000 copies at one time) and the image quality after multiple use (200,000 copies at one time) were evaluated as follows.

Image quality density 1.0 or more ◎ (Very good image quality) 0.6~
1.00 (Good image quality) Less than 0.6 △ (Blurred image) When the (photosensitive layer) is doped with impurities and the amount of nitrogen is controlled, the characteristics are significantly improved. It can also be seen that good results can be obtained by appropriately selecting the composition and thickness of this photosensitive layer, blocking layer, and surface modification layer.

[Brief explanation of the drawing]

The drawings show examples of the present invention, in which Fig. 1 is a cross-sectional view of a photoreceptor, Fig. 2 is a graph showing resistance changes of a-8iN:H depending on the amount of nitrogen, and Fig. 3 is a graph showing impurity doping. Figure 4 is a graph showing the change in the optical energy gap of a-siN:a depending on the amount of nitrogen. Figure 5 is a graph showing the change in the optical energy gap of a-8i(N):H depending on the amount of carbon. Graph showing changes in the optical energy gap of 8iC:H, Figure 6 is a schematic cross-sectional view of a glow discharge device, Figure 7 is a schematic cross-sectional view of a vacuum evaporation device, Figure 8 is a cross-sectional view of a gas discharge tube, FIG. 9 is a diagram showing each characteristic of the photoreceptor. In addition, in the symbols shown in the drawings, 1...... Support substrate 2...
・・・・・・・・・・・・Inorganic material layer (blocking layer) 3 ・・・・・・・・・・・・・・・ a-8iN:H layer (photoconductive layer or photosensitive layer) 4・・・・・・・・・・・・・・・
...a-3iC:H layer (surface modified layer). Agent Patent Attorney Hiroshi Aisaka Figure 1 Figure 2 Figure 3 PH3/SiH4+lJ+ B2Hs/Sik
+N2 Figure 5 Figure 6 Figure 7 Figure 3 Figure 8

Claims (1)

[Scope of Claims] 1. A base, a charge blocking layer of 100A to 1 μm thick formed on this base made of an inorganic substance, and a nitrogen atom-containing amorphous hydrogenated and/or or fluorinated silicon with a thickness of 2
A recording body comprising a photoconductive layer with a thickness of ~80 pm and a surface modified layer with a thickness of 100 to 5000 A made of amorphous hydrogenated and/or fluorinated silicon carbide formed on the photoconductive layer. . 2. The nitrogen atom content of the photoconductive layer is 1 to 30 atoms.
c%, the carbon atom content of the surface modified layer is 40 to 90ato
mic %, the recording medium according to claim 1. 3. The nitrogen atom content of the photoconductive layer is 15 to 25 atoms
ic%, the carbon atom content of the surface modified layer is 40 to 70 a
tomic %. 4. A record as set forth in any one of claims 1 to 3, wherein the photoconductive layer has a specific resistance of 101 oΩ-m or more due to doping with an element of group 1 [A of the periodic table]. body. 5. The recording medium according to claim 4, wherein the photoconductive layer has a specific resistance of 10120-α or more due to doping with an HA group element of the periodic table. 6. The recording medium according to any one of claims 1 to 5, wherein the charge blocking layer has a specific resistance of 10 13 Ω-m or more. 7. Charge blocking layer is 5inXSiOi, Al
xCh, MgO, ZnO, PbO, Cab, Bed,
Bad, Zr0t, TiO2, Ta206, CeO2
The 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 , SnO2. 8 The thickness of the charge blocking layer is 400 to 5000 A
The recording medium according to any one of claims 1 to 7, wherein the photoconductive layer has a thickness of 5 to 30 μm and the surface modified layer has a thickness of 400 to 2000 Å.