JPS6250837A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain a good output image having a high optical sensitivity and an excellent anti-crystallization property and a less tendency for generating cracks by forming an electric charge generating layer of the photosensitive body having a functional separation type of a Se series using a specific amorphous Se.Te.As alloy according to a vacuum deposition. CONSTITUTION:The titled body is formed by laminating an electric charge transfer layer (CTL) 2 composed of the amorphous Se.Te alloy and the electric charge generating layer (CGL) 4 composed of the amorphous Se.Te.As alloy in order on a conductive substrate 1, and by providing an intermediate layer composed of a mixed composition of both prescribed layers between the CTL 2 and the CGL 4, and by forming the CGL 4 from the amorphous Se.Te.As alloy having 61-90 deg.C a glass transition point according to the vacuum deposition method. Thus, as the depositing material having 61-90 deg.C the glass transition point is used to the CGL 4, the good anti-crystallization property of the titled body is obtd. The charge- transfer between both layers is effected smoothly by providing the intermediate layer 3 having the mixed composition of the CTL 2 and the CGL 4, and the electric charge does not accumulate, and the lowering of the electric charging property, and the increasement of a residual voltage are prevent, and the tendency for generating a crack is lessened in the vapor deposition, thereby stabilizing the property of the titled body and obtaining the good image.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical field to which the invention pertains] The present invention provides a charge transport layer on a conductive substrate,! The present invention relates to a selenium-based functionally separated electrophotographic photoreceptor formed by sequentially laminating load-generating layers.

[Prior art and its problems]

As an amorphous selenium-based photoconductive material used as an electrophotographic photoreceptor (hereinafter simply referred to as a photoreceptor), pure selenium/
In addition to selenium-tellurium alloys, selenium-arsenic alloys are also used. A photoreceptor having a photosensitive layer made of A328θ3 is known as a photoreceptor with excellent crystallization resistance and printing resistance, but the charging potential decreases significantly due to optical fatigue, and when using it, The complexity of installing a pre-static discharge process, etc., is an obstacle to downsizing the photoreceptor, for example, reducing the diameter of the photoreceptor cylinder. Furthermore, arsenic, which is one of the elements used, is expensive, and the advantage of Ic ABaBe3 being that it has a high glass transition point makes manufacturing equipment complicated and expensive, making it difficult to reduce the cost. Therefore, JP-A-55-134
As seen in Japanese Patent No. 856, a charge transport layer made of Se or Be-To gold alloy is formed on a conductive substrate, and a charge generation layer made of Se-As alloy (A13: 30 to 42 wt%) is formed thereon. Attempts have been made to reduce arsenic consumption and improve light fatigue resistance and durability using laminated functionally separated photoreceptors. However, in a photoreceptor with such a structure, there is a difference in thermal expansion coefficient between the charge transport layer and the charge generation layer, so cracks often occur in the charge generation layer due to internal stress during lamination by vacuum evaporation. These cracks also appear on copies, significantly impairing image quality and rendering the photoreceptor unusable.

Furthermore, a photoreceptor using an amorphous selenium-germanium alloy is known (W-Kokai No. 52-58925).

Although the addition of germanium significantly raises the glass transition point of the alloy and improves the crystallization resistance of the photoreceptor, it also significantly lowers the photosensitivity and increases the residual potential. Furthermore, if one takes into consideration the increased number of defects on the surface of the photosensitive layer that appear in output images, and the difficulty of vapor deposition, it is difficult to make a practical photoreceptor.

[Purpose of the invention]

SUMMARY OF THE INVENTION An object of the present invention is to eliminate the above-mentioned drawbacks and provide a photoreceptor that has high photosensitivity, excellent crystallization resistance, and can produce high-quality output images without cracking during vapor deposition. do.

[Key points of the invention]

An object of the present invention is to sequentially laminate a charge transport layer made of an amorphous selenium-tellurium alloy and a charge generation layer made of an amorphous selenium-tellurium-arsenic alloy on a conductive curved substrate; In a photoreceptor having an intermediate layer between a charge transport layer and a charge generation layer, in which the compositions of both layers are mixed, the vapor deposition material used for forming the charge generation layer is amorphous selenium, tellurium,
This is achieved by setting the glass transition point of the arsenic alloy to 61 to 90°C.

[Embodiments of the invention]

'4I: Example 1 As a vapor deposition material for a charge transport layer, 960 g of a selenium-tellurium alloy consisting of 5.5 ir of tellurium, a quantity of As tellurium 15 is, arsenic 5
A quartz boat was filled with 90 g of a selenium-tellurium-arsenic alloy consisting of ffif% and the remainder selenium, and set in a vacuum deposition tank. A support shaft with an outer diameter of 90 mm and a length of 32
Attach a 0■ aluminum cylinder and rotate the support shaft to 10 rp.
Rotate with m. The vacuum chamber was closed and evacuated, and when the degree of vacuum reached 5 × 10 Torr, the heater of the charge transport non-evaporation boat was turned on, and the temperature of this boat was raised to 325 °C in 25 minutes, and this temperature was increased. to evaporate the selenium-tellurium alloy.

The point at which evaporation of all 960 g is completed is determined by the rise in boat temperature, and the time required to maintain the temperature at 325° C. is 24 minutes. Two minutes after evaporation is complete, turn off the boat heater. In addition, the holding time at 325°C is 1
At 6 minutes, the heater of the charge generation layer deposition port is turned on, raised to 340° C. in 5 minutes, maintained at this temperature for 10 minutes, and then turned off. This 10 minutes is the time required to evaporate approximately 60 inches of the filling. The heater of the charge generation layer deposition boat was turned off, the vacuum was broken after 2 minutes, and the vacuum chamber was opened after 10 minutes and the photoreceptor was taken out. In this way, the selenium film formed on the conductive substrate 1 as shown in FIG.
A photoreceptor is obtained which has an intermediate layer 3 in which materials of both layers are mixed between a charge transport layer 2 made of a tellurium alloy and a charge generation layer 4 made of a selenium-tellurium-arsenic alloy. The film thickness when only the charge transport layer was deposited using the method of this example was approximately 60 it.
It is n. Furthermore, when the entire amount of 90 g of the charge generation layer vapor deposition material is vapor-deposited, the film thickness is about 9 μm, but in the photoreceptor of this example as described above, the charge generation layer vapor deposition material is about 60 μm thick.
Since only % is evaporated, the film thickness is 5 to 6 μm, and a part of the film overlaps with the charge transport layer to form an intermediate layer.

Example 2 The vapor deposition material for the charge generation layer was 20% by weight of tellurium and 5% by weight of arsenic.
A photoreceptor was prepared in accordance with Example 1 except that the photoreceptor was made of a selenium-tellurium-arsenic alloy consisting of % selenium and the remainder selenium.

Example 3 A photoreceptor was produced in accordance with Example 1 except that the vapor deposition material for the charge generation layer was a selenium-tellurium-arsenic alloy consisting of 25% by weight of tellurium, 2% by weight of arsenic, and the balance selenium.

Example 4 15% by weight of tellurium as a vapor deposition material for the charge generation layer.

Using a selenium-tellurium-arsenic alloy consisting of 5% arsenic and the balance selenium, the temperature of the boat for charge generation layer deposition was tl-3.
A photoreceptor was produced in the same manner as in Example 1 except that the temperature was raised to 60 tl in about 5.5 minutes and maintained at this temperature for 7 minutes.

Example 5 A selenium-tellurium-arsenic alloy consisting of 20% by weight tellurium, 5% by weight arsenic, and the balance selenium was used as the charge generation layer vapor deposition material, and the temperature of the charge generation layer boat was raised to 380° C. in about 7 minutes. A photoreceptor was produced in the same manner as in Example 1 except that the temperature was maintained for 5 minutes.

Comparative example 1 15% by weight of tellurium as a vapor deposition material for the charge generation layer.

A photoreceptor was produced in accordance with Example 1, except that a Cere/tellurium alloy consisting of the remainder Cere/ was used.

Comparative example 2 20% by weight of tellurium as a vapor deposition material for the charge generation layer.

A photoreceptor was prepared in accordance with Example 1 except that a selenium-tellurium alloy was used with the balance being selenium.

Comparative example 3 25% by weight of tellurium as the evaporation material for the cargo-generating layer.

A photoreceptor was produced in accordance with Example 1 except that a selenium-tellurium alloy was used with the balance being selenium.

Table 1 shows the film thicknesses and electrophotographic properties of the photosensitive layers of these eight photoreceptors. The charging potential here is +6.0KV in the dark.
This is the surface potential charged by corona discharge of This is the value required for the initial charged potential value of 100 OV to attenuate to 500 V when exposed at an illuminance of 3 lux.The residual potential is the value after exposure of 10 lux seconds.

Next, the glass transition points of the vapor deposition materials used to form the charge generation layers of these eight photoreceptors were investigated. Using a standard scanning differential thermal analyzer manufactured by Rigaku Denki ■, the sample weight was 30 ± 1 mg.
+ Measurement was performed at a temperature increase rate of 10° C./min. Table 2 shows the glass transition points of these eight types of samples. The transition start temperature is shown as the glass transition point.

f　　　　　Table Next, an accelerated life test was conducted to examine crystallization resistance.

These 8 photoconductors can be printed at a copying speed of 3 on A4 paper.
It was installed in a commercially available Carlson type dry-type plain paper copying machine at 0 sheets per minute, and after making actual copies of 1000 sheets of A3 size originals and applying a load of actual use to the photoreceptor, the temperature was 50±1.
The product was left in an atmosphere with a relative humidity of 8 to 20 degrees centigrade, and the time it took for crystallization to begin to be observed was determined as the lifespan. The results are shown in Table 3.

E.3 As is clear from Tables 2 and 3, the lifespan of each of the comparative photoreceptors in which the glass transition point of the vapor-deposited material used for the charge generation layer was 60°C or lower was less than 100 hours. ,
The photoreceptors of the examples all have very long lives. The higher the glass transition point of the evaporation material, the longer the life of the photoreceptor and the better its crystallization resistance. However, if the glass transition point is too high, the amount of arsenic added to the evaporation material will increase, making the evaporation process more difficult. Unfortunately, the cost of materials will also increase. Further, this is not preferable because it increases optical fatigue of the photoreceptor. It is preferable that the glass transition point of the vapor-deposited material for the charge generation layer is in the range of 61 DEG C. to 90 DEG C., since practically sufficient crystallization resistance can be obtained.

In addition, since an intermediate layer is formed in which the composition of the charge transport layer and the charge generation layer is mixed, the composition transition between the two layers occurs gradually, and the charge transfer between the two layers occurs smoothly, so that the boundary between the charge transport layer and the charge generation layer is mixed. There is no charge accumulation in the photoreceptor, and even if the photoreceptor is used repeatedly, there is little deterioration in charging performance and little increase in residual potential, and the characteristics are stable9.Furthermore, cracks do not occur during vapor deposition.

〔Effect of the invention〕

According to the present invention, a charge transport layer made of an amorphous selenium-tellurium alloy and a charge generator made of an amorphous selenium-tellurium-arsenic alloy are sequentially laminated on a conductive substrate, and the charge transport layer and the charge generator In a photoreceptor having an intermediate layer having a mixture of compositions of both layers, the charge generation layer is formed by vacuum evaporation of an amorphous selenium-tellurium-arsenic alloy having a glass transition point of 61 to 90°C. to form. By using such an amorphous selenium-tellurium-arsenic alloy as a vapor deposition material, it is possible to obtain a photoreceptor that has high photosensitivity, excellent crystallization resistance, and can produce high-quality images without cracking during vapor deposition. Very effective.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a main part of an embodiment of the present invention. 1... Conductive substrate, 2... Charge transport layer, 3... Intermediate layer, 4... Charge generation layer. Figure 4

Claims (1)

[Claims] 1) A charge transport layer made of an amorphous selenium-tellurium alloy and a charge generation layer made of an amorphous selenium-tellurium-arsenic alloy are sequentially laminated on a conductive substrate, and the charge transport layer and the charge generation layer are laminated in sequence on a conductive substrate. In an electrophotographic photoreceptor having an intermediate layer having a mixture of compositions of both layers, the charge generation layer is made of amorphous selenium, tellurium, and the like having a glass transition point of 61 to 90°C.
An electrophotographic photoreceptor characterized by being formed by vacuum deposition of an arsenic alloy.