JPS6254269A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain an electrophotographic sensitive body which has excellent performance to withstand crystallization and high photosensitivity and maintains the stable performance with the lessened decrease of electrostatic charge potential and increase of residual potential in the continuous repeated use by using respectively specifically composed amorphous selenium-tellurium-arsenic alloys for an electric charge transfer layer and charge generating layer and providing an intermediate layer in which the compsns. of both layers are mingled between the two layers. CONSTITUTION:The CTL of the photosensitive body having the intermediate layer in which the compsn. of both layers are mingled between the CTL and the CGL consists of the amorphous selenium-tellurium-arsenic alloy contg. 1-15wt% tellurium and 0.01-5wt% arsenic and the CGL consists of the amorphous selenium-tellurium- arsenic alloy contg. 5-30wt% tellurium and 0.1-10wt% arsenic. The selenium- tellurium-arsenic alloy is packed as a vapor deposition material for the CTL in a boat and the alloy is packed as a vapor deposition material for the CGL in a quartz boat. Both boats are set in a vacuum deposition vessel. The vapor deposition vessel is closed and the inside thereof is evacuated, then the vapor deposition materials are evaporated to the specified profile of the vapor deposition compsn. ratio, by which the variance of the photosensitive characteristics is decreased.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of the Invention] The present invention relates to a selenium-based functionally separated electrophotographic photoreceptor comprising a charge transport layer and a charge generation layer successively laminated on a conductive substrate.

[Prior art and its problems]

As an amorphous selenium-based photoconductive material used as an electrophotographic photoreceptor (hereinafter simply referred to as a photoreceptor), in addition to pure selenium and a selenium-tellurium alloy, a selenium-arsenic alloy is also used. A photoreceptor having a photosensitive layer made of As 2Bθ3 is known as a photoreceptor with excellent crystallization resistance and printing resistance. However, it is complicated to install the pre-static neutralization process, which hinders the miniaturization of the photoreceptor, for example, reducing the (H diameter) of the photoreceptor cylinder.Also, one of the elements used Due to the high glass transition temperature of some arsenic and the high glass transition point of A8aSθ3, the manufacturing equipment becomes complicated and expensive, making it difficult to reduce the cost.

So tp! As seen in Japanese Patent Publication No. 55-134856, a charge transport layer made of 86 or 8θ-Tθ alloy on a conductive substrate, and secondly a Bθ-Aii alloy (
Attempts have been made to reduce arsenic consumption and improve light fatigue resistance and durability by using a functionally separated photoreceptor in which a charge generation layer consisting of AS: 30 to 42 layers is laminated. However, in photoreceptors 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. , this crack also appears on the copy,
This significantly impairs image quality and makes the photoreceptor unusable.

[Purpose of the invention]

The present invention eliminates the above-mentioned drawbacks, has excellent crystallization resistance performance,
Another object of the present invention is to provide a photoreceptor for electrophotography which has high photosensitivity, is stable with little variation in characteristics during repeated and continuous use, and has good performance.

[Key points of the invention]

The object of the present invention is to provide a charge transport layer (hereinafter referred to as CT) on a conductive substrate.
(also referred to as L), charge generation layer (hereinafter also referred to as OGL)
In a photoreceptor having an intermediate layer between OTL and CGL in which the compositions of both layers are mixed, the OTL contains 1 to 5% by weight of tellurium and 0.01 to 5% by weight of arsenic. This is achieved by making a photoreceptor made of an amorphous selenium-tellurium-arsenic alloy containing an OGL of 5 to 30% by weight of tellurium and 0.1 to 1 g of arsenic. Ru.

[Embodiments of the invention]

Next, preferred embodiments of the present invention will be described in detail.

Example 1 As a vapor deposition material for OTL, 5.5% by weight of tellurium and 0.5% by weight of arsenic were used.
900 g of a selenium-tellurium-arsenic alloy consisting of 5 layers, the balance being selenium, in a stainless steel 5U8430 boat.
Filled with selenium, tellurium, and OGL vapor deposition materials consisting of 15 layers of tellurium, 3% by weight of arsenic, and the balance selenium.
Fill a quartz boat with 130 g of arsenic alloy and set it in a vacuum deposition tank. Similarly, the surface temperature of the support shaft provided in the vacuum deposition tank was controlled to about 65°C, and the outer diameter was 90 f.
An aluminum cylinder with a length of 320 cm was fully loaded, and the support shaft was rotated at 10 rpm. Close the deposition tank,
Evacuate the boat, and when the vacuum level reaches 5 x No Torr, turn on the heater of the boat wearing 0TLH,
The temperature of the boat is raised to 325° C. in about 25 minutes and held at this temperature to evaporate the -C selenium-tellurium-arsenic alloy. The point at which evaporation of all 900 g is completed is determined by the increase in boat temperature, and the required 325°C is reached.
The holding time is 28 minutes.

Two minutes after evaporation is complete, turn off the boat heater.

In addition, when the above holding time at 325°C reached 20 minutes, the heater of the boat used for aGL# was turned on, the temperature of this boat was raised to 340°C in 5 minutes, and this temperature was maintained for 13 minutes. Then turn off the boat's heater. ]33 minutes is the time required to evaporate approximately 60 g of the 11,130 g charge of alloy. This 60% evaporation is desirable in order to keep the vapor deposition composition ratio profile constant and reduce variations in photosensitive characteristics.

After 2 minutes of turning off the heater of the caLM wearing boat, break the vacuum. 9. After 10 minutes, open the vacuum chamber and take out the photoreceptor. In this way, the OTL 2 made of a selenium-tellurium-arsenic alloy formed on the conductive substrate 1 as shown in a conceptual cross-sectional view of main parts in FIG. A photoreceptor is obtained which has an OGL 4 made of an alloy having different composition ratios, and an intermediate layer 3 interposed therebetween in which the materials of both layers are mixed.

Examples 2 to 15 The composition ratios of the alloys of the OTL vapor deposition material and the OGL vapor deposition material were changed as shown in Table 1, and the temperature of the support shaft surface and the OTL
Examples 2 to J5 were carried out in the same manner as in Example 1, except that the set temperatures of the vapor deposition boat and the OGL vapor deposition boat, the temperature increase time to the set temperature, and the holding time at the set temperature were shown to the two people. A photoreceptor was fabricated.

Note that Table 11 and Table 2 also show the numerical values for Example 1.

E 1 Table E 2 Table By the method of these examples (the film thickness when only ITTI is evaporated is about 57 μm, and when only CGL is evaporated L7, the film thickness is 7 to 8 μm, but as mentioned above, In the photoreceptors of these Examples, both layers are laminated to partially overlap to form an intermediate layer.

Furthermore, in forming the tit OGL in these Examples, the entire amount of cGTr evaporation layer material filled into the boat was not evaporated, but was stopped using an evaporation needle of approximately 60 mm, which was not achieved by electrophotography of the photoreceptor). This is to reduce variations in characteristics. In other words, when a selenium-tellurium-arsenic alloy, which is a deposition material for nGT, is evaporated in a vacuum, fractionation occurs due to the difference in vapor pressure of the constituent elements of the base metal, and the composition of the constituent elements changes in the thickness direction of the deposited layer. Although a change in the ratio occurs, the profile of the change differs from deposition to deposition, and it is difficult to make a uniform determination, and the variation increases as evaporation approaches the end.

Therefore, if the entire amount filled is evaporated, the ratio of the elements selenium, tellurium, and arsenic on the CAL surface will vary greatly from photoreceptor to photoreceptor, and the electrophotographic characteristics, crystallization resistance, etc. will vary greatly. Furthermore, when the entire filling is evaporated, evaporation residues such as impurities are scattered, resulting in defects on the core, cracks, and surface. If the filling amount is limited to evaporation of 20 to 80 Ly6, these drawbacks can be prevented and it is effective, and in particular, if the filling amount is about 60 Ly6 as in the example, there is relatively little wastage of vapor deposition material, which is preferable.

Comparative Example 1 As a vapor deposition material for OTL, 900 g of selenium-tellurium alloy consisting of 5.5 wt % tellurium and the remainder selenium color, OGL
A photoreceptor was produced according to Example 1 using 130 g of a selenium-tellurium alloy consisting of 20% by weight tellurium and the balance selenium as a vapor deposition material. The difference between the evaporation conditions and Example 1 is that the 0TTJ evaporation material was evaporated at a boat temperature of 325°C.
, since the holding time ends, the heater of the boat is turned off after 2 minutes, and when the holding time reaches 14 minutes, the heater of the boat for 0GTJ deposition is turned on.

Comparative Example 2 Comparison except that a selenium-tellurium alloy consisting of 8.5% by weight tellurium and the balance selenium was used as the vapor deposition material for CTL, and a selenium-tellurium alloy consisting of 25% tellurium, 1% polypropylene, and the balance selenium was used as the vaporization material for OGL. A photoreceptor was produced in the same manner as in Example A.

Comparative Example 3 A selenium-tellurium alloy consisting of Tenor 5.5 F IS and the balance selenium as a vapor deposition material for CTL, and a selenium-tellurium-arsenic alloy consisting of Tellurium 20 F IS, arsenic II superior, and selenium as an OGL vapor deposition material. A photoreceptor was produced in the same manner as in Comparative Example 1 except that .

Comparative Example A photoreceptor was produced in the same manner as in Comparative Example 3, except that a selenium-tellurium-arsenic alloy consisting of 20% by weight tellurium, 3% by weight arsenic, and the balance selenium was used as the vapor deposition material for CGL.

The film thicknesses and electrophotographic properties of the photosensitive layers of the 5 photoreceptors of Examples and 4 of Comparative Examples are shown in Table 3. Here, the charging potential is +6. This is the surface potential charged by OKV's corona discharge, and the retention rate indicates the potential retention rate after 1 second in a dark place. #) When exposed to an illuminance of 3 lux, the initial value of the surface potential of ko000v is 500
The residual potential indicates the surface potential after receiving an exposure amount of 10 lux·sec.

Fang 3 All of the photoreceptors in the Examples and Comparative Examples in the table have good initial electrophotographic characteristics.

Next, ion microanalysis (IMA) was performed on monitor pieces that were simultaneously deposited on aluminum circles #10 in diameter during the deposition of the 19 photoreceptors.

One analysis was carried out using a special Xσ■B Tatsui laboratory model IMA-2A using the aluminum mask method (diameter 0.B wa hole), using Osr as the -order ion, and an accelerating electric field of 15ke.
V.

Table 4 shows the average weight percent of tellurium and arsenic in the charge generation layer when analyzed under the conditions of an ion current of 0.5 μA and a beam diameter of 1.4 m.

Table 4 Next, a repeated copying test was conducted on these photoreceptors in order to observe changes in the characteristics of the photoreceptors when copying was performed repeatedly.

In order to perform repeated copying tests, we used a commercially available Carlson method dry-type plain paper copying machine with a copying speed of 30 sheets/min for A4 paper, removed the developing device and cleaning blade, and installed the surface in the position of the developing device. At the same time as installing the electrometer probe, the power supply for the installed heater was modified so that it would not turn on.

Next, prepare an sample chart. An ensample chart is an A3 paper-sized manuscript that is sized 3 times in the length direction.
Divide into equal parts, and the optical temperature of each part is D0=1.3,
This is a chart in which Do=0.3 and D0=0.07. Insert the photoreceptor sample into the copying machine, and with the original platen cover open, check that the charged potential is between '750 and '79.
Adjust vcvs so that it becomes 0■. Next, place the sample chart, close the document platen cover, and set D0=0.
Adjust the potential of part 3 to 250 to 290 V. After adjustment, continuous operation was performed for 300 times.
Record the change in potential of these three parts. This test was conducted for each photoconductor, and the D0 of the 1st and 300th
= 0.3, that is, the amount of change in dark area potential (Δvs), and the potential of the 3001ffi (2) D0=O, O'7 (2) area, that is, the output area potential (Vw). It is shown in Table 5.

The negative sign of the amount of change in dark area potential (ΔVe) in Table 5 indicates that the potential at the 300th time is smaller than the potential at the first time. Photoreceptors containing relatively large amounts of tellurium and arsenic in the MA for the charge generation layer, e.g., Examples 12-]
Although ΔV8 tends to be slightly large for No. 5, all photoreceptors including those have sufficiently practical values. This dark area potential corresponds to the charging potential of the photoreceptor, and the above results show that even if the photoreceptor is used repeatedly, its charging performance hardly changes and does not deteriorate.

In addition, the potential (Vw) at the paper exit part increases slightly at first for all photoreceptors, but it becomes saturated after about 100 times, and no increase is observed after that until 14,300 times, so there is no problem in practical use. This potential at the paper output portion corresponds to the residual potential of the photoreceptor, and indicates that no problematic increase in the residual potential is observed even when the photoreceptor is used repeatedly. 'However, in the photoreceptor of Example 6.10.14, in which the OTL vapor deposition material was made of a selenium-tellurium-arsenic alloy containing a relatively large amount of arsenic (more than 5% by weight), the Vw was slightly large, and it was difficult to cover the entire photosensitive layer. There is a tendency for the residual potential to increase due to the addition of arsenic.

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

These 19 photoreceptors were sequentially installed in a commercially available Carlnon-type dry plain paper copying machine with a copying speed of 30 sheets per minute on A4 paper, and 1000 sheets of A3 paper-sized originals were actually copied. After applying the load of actual use to the body, the temperature is 50±
The product was left in an atmosphere of 1° C. and relative humidity of 8 to 20%, and the time it took for crystallization to begin to be observed was determined as the lifespan. The results are shown in Table 6.

-]8- E 6 As is clear from Table 6, the life of the photoreceptor of Comparative Example 1.2 in which neither the OTL nor OGL layers contain arsenic is ]0
It's short and takes 0 hours. Furthermore, although arsenic is added to OGL, as shown in Table 4, the life of the photoconductor of Comparative Example 3.4, which contains relatively little 1, is several times longer than that of the photoconductor of Comparative Example 1.2. However, it does not show a long life of 500 hours or more like the photoreceptor of the example. However, arsenic is added to both OTL and OGI layers.
That is, in the photoreceptor of Example in which the entire photosensitive layer contains arsenic, the arsenic content of the CGL is equal to that of Comparative Example 3.
50 also in Examples 1, 2.3.4, which is about the same as 4.
It has a long life of 0 hours or more.

□In this way, when arsenic is included in both the OTL and CGL layers, the crystallization resistance of the photoreceptor is greatly improved, and the sensitivity to long wavelength light is also high. Although the tendency is remarkable, on the other hand, the phenomenon of photofatigue occurs in the electrophotographic properties, and when a photoreceptor is used repeatedly and continuously, the properties fluctuate, making it difficult to obtain stable, high-quality images. Also, it becomes difficult to deposit each layer, and the cost of deposition materials increases. The arsenic content is preferably 0.01 to 5% by weight in CTL and 1 to 10% by weight in OGL, and more preferably 1 to 1% by weight in OGL. OGL niote is 0.5 to 5% by weight.

Furthermore, if the tellurium content of both the OTL and OGL layers, especially the OGL, decreases, the photosensitivity of the photoreceptor will deteriorate, and if the tellurium content increases, the band '11 potential will decrease.

As the tellurium content in the OTL increases, the temperature dependence of the electrophotographic properties of the photoreceptor also tends to increase. The tellurium content in OTL is 1. ~15% by weight,
It is preferably 5 to 30% by weight in OGL, more preferably 2 to 10% by weight in OTL, and 10 to 20% by weight in OGI.

In the embodiments described above, OGL vapor deposition is started during OTL vapor deposition to form an intermediate layer between the two layers in which the compositions of both layers are mixed. By interposing such an intermediate, O
Since the composition ratio shifts from TL to OGL gradually, the charge transfer between the two layers is smoothed and charge accumulation at the boundary is eliminated, reducing charging performance deterioration and residual charges when the photoreceptor is used repeatedly and continuously. This is very effective because it can reduce the rise in potential.

〔Effect of the invention〕

According to the present invention, the charge transport layer is made of tellurium 1 to 15 weight mt.
Amorphous selenium-tellurium-arsenic alloy consisting of 0.01 to 5% arsenic by weight and the balance selenium, the charge generation layer is Delu b~
By making an amorphous selenium-tellurium-arsenic alloy consisting of 30% by weight, 0.1 to 0% arsenic, and providing an intermediate layer with a mixture of the compositions of both layers between the two layers, crystallization resistance can be achieved. It is possible to obtain an electrophotographic photoreceptor with excellent performance, high photosensitivity, and stable performance with little decrease in charging potential and little increase in residual potential during repeated and continuous use.

[Brief explanation of drawings]

FIG. 1 is a conceptual sectional view of a main part of a photoreceptor according to an embodiment of the present invention. DESCRIPTION OF SYMBOLS 1... Conductive substrate, 2... Charge transport 1-53... Intermediate layer, 4... Charge generation layer. Figure 1: Charge generation layer, intermediate layer, electric charge and attached layer - causal layer and space substrate

Claims (1)

[Claims] 1) A charge transport layer and a charge generation layer are sequentially laminated on a conductive substrate, and an intermediate layer having a mixture of compositions of both layers is provided between the charge transport layer and the charge generation layer. In the electrophotographic photoreceptor, the charge transport layer contains 1 to 15% by weight of tellurium;
Amorphous selenium/tellurium containing 0.01-5% by weight of arsenic
1. A photoreceptor for electrophotography, characterized in that the charge generation layer is made of an amorphous selenium-tellurium-arsenic alloy containing 5 to 30% by weight of tellurium and 0.1 to 10% by weight of arsenic. 2) In the photoreceptor according to claim 1, the charge transport layer contains 2 to 10% by weight of tellurium and 0.1 to 3% by weight of arsenic.
The charge generating layer is made of an amorphous selenium/tellurium/arsenic alloy containing 10 to 20% by weight of tellurium and 0.5 to 5% by weight of arsenic. A photoreceptor for electrophotography.