JPS5974563A - Electrophotographic receptor - Google Patents

Abstract

PURPOSE:To obtain an image having high contrast and high density, and to obtain a good image even in high humidity, by forming a conductive layer made of Te on a substrate, and forming an Se type photoconductive layer and an insulating layer on this conductive layer in succession. CONSTITUTION:The conductive layer 2 is formed on a conductive substrate made of aluminum or the like or a substrate 1 of a polyester film or the likeby thinly vapor depositing Te. A photoconductive layer 3 made of Se or contg. Se as a main component, and also Te or As is formed on the layer 2, and then, an insulating layer 4 of a polyester film or the like is formed on the layer 3. When the layer 3 is substituted for a 2-layer type photoconductive layer 3' consisting of a charge transfer layer 3b of Se type doped with <=4,000ppm halogen, and a charge generating layer 3a contg. 5- 25% Te, the composite layer 3' is made larger in spectral sensitivity region than the single Se layer 3, and enhanced in efficiency. When the layers 3, 3' are formed, it is preferable to heat temp. of the substrate to 55-65 deg.C to carry out vapor deposition, and it is more desirable to heat treat it to 30-65 deg.C after forming the layer 4. As a result, the Te layer 2 is enhanced in charge injection performance at the time of primary charging, and since it has blocking ability at the time of secondary charging, high contrast is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrophotographic photoreceptor in which an electrostatic m1 image is copied onto a dielectric film as a charge pattern.

Generally, an electrophotographic photoreceptor is composed of a conductive layer, a photoconductive layer, and an insulating layer.
-23910 or 43-24748.
) and simultaneous charging light image exposure (from which an electrostatic latent image is formed). Electrophotographic photoreceptors are usually made by forming a thin film of a photoelectric material on a conductive support by vacuum deposition.

Conventionally, electrophotographic photoreceptors have been formed in which conductive and laminated layers are made of aluminum Cf1J, the photoconductive layer is made of selenium (Se), and the insulating layer is made of PET. This selenium photoconductor has P-type characteristics, and when subjected to negative primary corona charging, positive secondary corona charging, and simultaneous photoimage exposure and full-surface exposure in the latent image forming process, -order charging occurs. At times, the dark resistance of the selenium photoconductor 1+- increases, and the injection of carriers from the conductive layer side decreases. For this reason, the effect of forming free charge pairs above and below the insulating layer was not sufficiently exhibited, and high electrostatic contrast could not be obtained.

As a result, the effective photosensitivity of the photoconductive insulating layer loses the effect that the primary charge is a sensitizing charge. Therefore, the photosensitivity depends only on the process of simultaneous photoimage exposure of secondary charging, so when secondary band 1 is AC, almost no contrast is obtained, and when the secondary band 1 is AC, very little contrast is obtained when the secondary band 1 is charged with DC corona charging. Only low contrast can be obtained.

Next, as an auxiliary means, while performing full exposure during the -th charge, or after performing full exposure after the first charge of C,
It was devised to perform optical image exposure at the same time as secondary charging.

This improved the contrast slightly by 1".

On the other hand, to obtain enough contrast for practical use,
In addition to the above-mentioned electrophotographic photoreceptor, a zinc oxide film is known that is formed by dispersing a powder of a phosphor ZnCd5 and a powder of a photoconductive material Z'nO in a resin binder, but there is a problem in terms of moisture resistance. - Ryuko's invention was made to solve the above problems, and includes a tellurium conductive layer on one side of a selenium-based photoconductive layer and an insulating layer on the other side.
- By providing an electrophotographic photoreceptor, it is possible to obtain an image with high contrast and high density.

The present invention will be described in detail below with reference to the drawings.

Figure 1 shows the basic structure of the present invention, where 1 is made of a conductive material such as aluminum (A), copper (Cu), stainless steel (8uS), or an insulating material such as PET. It is a support layer. A conductive layer 2 of 40 or more high purity tellurium (Te) of 0.05 μm to 2 μm is applied to one plate surface of the support IN 1 by means such as vacuum evaporation or sputtering.
A thickness of I is formed. Thereafter, selenium (Se) or a selenium-based photoconductive layer 3 containing selenium as a main component is formed on the top surface of the tellurium conductive layer 2, and then a polyester (1 (114 Ω or more) polyester with high volume resistivity that transmits visible light) is formed on the top surface of the tellurium conductive layer 2. (PET), xylene, and other resins such as acrylic, epoxy, urethane, fluorine, styrene, carbonate, etc., and a transparent insulation IN 4 is pasted thereon. be done.

The basic structure of this invention has been shown above, but preferably the first
As shown in FIG. 2, the light guide layer 3 shown in the figure is made of selenium or selenium-based secular transport/113a in which selenium is doped with halogen.
It is preferable to form the α charge generation layer 3b mainly composed of selenium and tellurium.

That is, in order to obtain high contrast, the charges injected from the conductive layer 2 during temporary charging must move through the photoconductor I@3' without being blocked.

Furthermore, it is known that the mobility of a selenium-based photoreceptor decreases if it is doped with even a small amount of impurities other than halogen. However, during the simultaneous light image exposure of secondary charging and the entire surface exposure in the final process, the light sensitivity range of a pure selenium single layer is limited to the short wavelength range of visible light, resulting in poor efficiency. It is necessary to expand the spectral sensitivity range and improve efficiency by doping with Te, As, etc.

In order to satisfy the above two conditions at the same time, as shown in FIG. 2, a '1 charge generator 3b formed so thin as not to reduce the mobility is provided under the two transparent insulating layers. In order to expand the photosensitivity wavelength range, increase the photosensitivity, and improve the efficiency during simultaneous charging light image exposure and full-surface exposure, selenium lζ halogen ~ 4000 ppm is added between the charge generation layer 3b and the conductive layer 2. By providing a doped steel wire 3a, the mobility of the charge injected from the conductor 92 during soldering is greatly increased.

- It is necessary to improve the secondary sensitizing charging effect.

Furthermore, this photoconductivity)-3' will be explained in detail. The charge generation layer 3b described above is made of Se with a tellurium content of 5 to 25
-'re layer, 0. (It is formed to a thickness of 15-5μ.

If necessary, arsenic (As), silicon (Si), antimony (sb), or halogen may be doped for the purpose of preventing crystallization, improving sensitivity, and removing residual potential. Also.

The charge transport layer 3a contains 0 to 4 nQopp of halogen in highly purified selenium of 5 n (99,999%) or higher! It is doped with n and vacuum-deposited on the upper surface of the conductive layer 2 to a thickness of 20 to 70 μm.

At this time, the substrate temperature for vacuum deposition is set at 55 to 65°C. This is because when the substrate temperature becomes 55° C. or lower, the response becomes poor and contrast cannot be obtained even though the residual potential becomes high. Furthermore, if the temperature exceeds 65°C, the resistance of the photoconductive layer will drop significantly, and when a voltage is applied, the photoconductive layer 3'
This is due to the fact that the electric potential is no longer distributed between the two, and as a result, charges are injected and moved from the conductive layer 2 without distinguishing between bright and dark areas during the secondary simultaneous charging light image exposure, resulting in a loss of contrast.

Next, the conductive α layer 2, which is another key to achieving high contrast, will be explained. The requirements for the conductive layer 2 are: firstly, it must exhibit good injection properties during primary charging, and secondly, it must not be injected from the conductive layer 2 in order to obtain contrast between light and dark areas during secondary charging and simultaneous optical image scarlet light. is required. For a 7n imaging process, the light guiding layer 3'
Eccentric materials that are well matched are required. Tellurium conductivity in this invention! The special features of the single layer and the conventional conductive layer will be clarified through the following experiment.

A conventional selenium-based photoreceptor with a conductive layer made of aluminum and a photoreceptor of the present invention with a conductive layer made of tellurium were each coated with -2000
Examining the potential drop when strong full-plane exposure is performed after performing the dark corona zone "d" of V, it is found that in the case of aluminum (conventional example) there is a potential change of approximately 1000V, while that of tellurium (this proposal). In the case of tellurium, there are approximately 200 layers, which is significantly smaller than that of aluminum.
It can be seen that charges equivalent to 118 QOV have already been formed above and below the insulating layer due to QV dark charging. On the other hand, in the case of aluminum, the potential distribution of about -1oooV is
Occurred on the 11th floor.

It can be seen that charges equivalent to 1,000 V, which is about half of the dark charge of -2,000 V, are formed above and below the insulating layer, and charge injection is significantly worse than that of tellurium.

Next, assuming secondary charging, when the conventional photoreceptor and the photoreceptor of the present invention are positively corona charged to +20+1 nV, the potential changes are 1150 V[degrees].

As a result, it was found that the photoreceptor of the present invention has good injection properties during primary charging and has charge blocking properties during secondary charging, indicating that it exhibits characteristics that make it easy to obtain high contrast.

According to experiments conducted by the present inventors, the physical mechanism governing the injection properties at the interface between the tellurium conductive layer and the photoconducting layer was found to be similar to that of the tellurium photoconductor that was vacuum-deposited for about one month or less. , -20oQV corona charging in the dark and then full exposure, the same as the aluminum photoreceptor, -1000
It was found that potential distribution of V occurred, resulting in very poor injection performance. However, the tellurium photoreceptor is allowed to elapse for a predetermined period of time.

Or by forced aging with heat or light.

Although the above-mentioned good injection properties can be obtained, in the case of an aluminum photoreceptor, there is hardly any improvement in injection properties.

When forcibly heat-treating the tellurium photoreceptor, 30 to 6
Good results can be obtained by aging at 5° C. for about 1 to 60 hours.

The following four types of visibility can be considered as the physical tin that governs the injection property at the interface between the tellurium conductive layer and the photoconductive layer.

1) Surface condition of the tellurium conductive layer (for example, contact area).

2) Recombination center density of the photoconductive layer at the interface.

3) Difficulty in forming barrier layer due to difference in work relationship between selenium and tellurium.

4) Difficulty in forming barrier layer due to difference in work release between support layer and tellurium.

Next, several types of experiments were conducted to demonstrate the physical mechanism of the present invention, which will be explained step by step below.

■) Example 1. Reference Example 1 A conductive layer is formed by vacuum evaporating tellurium having a purity of 50 to a thickness of about 0.5μ on a drum-shaped aluminum support. 5n at substrate temperature 60℃
The charge transport layer is formed by vacuum depositing selenium having a purity of about 50 μm. Next, a 5e-Te alloy containing 8 layers of tellurium was vacuum-deposited to a thickness of about 0.5M on the charge transport layer to form a charge generation layer, and 20μ of P was deposited on the charge transport layer.
The photoreceptor of this invention was constructed by attaching an IBT film to form an insulating layer. A sample of Reference Example 1 was obtained one week after the photoreceptor was prepared.

Experiments were carried out under the following conditions using the samples that had been used for 1.5 months as samples for implementation 1*g 1 of the present invention.

Next, the sample was charged to -2000 V using a Scorotron capacitor, and then a light image was exposed at the same time as a 6.51 cv AC corona band 'α, and then the entire surface was exposed to obtain a silent latent image.

In the same manner, after the primary belt and the plate, a light image is exposed at the same time as +6.5 KV positive corona charging, and then the entire surface is exposed to obtain a C electrostatic latent image.

The above experiment was carried out for 1.5 months as shown in the table.
L 7'1m Actual 74M 1 No is '5 AC460V
, showed the highest contrast of DC600V. The static latent image of this implementation nJ 1 was developed with a magnetic brush, and then
When the image was transferred with -color, a good fJr image of high 4 degrees was obtained. Thereafter, when the static electricity was removed and the next image was repeatedly taken after cleaning, a good image was obtained without any residual potential afterimage.

Furthermore, the photoconductor of Example 1 was placed in a constant aeration chamber 1 with a relative humidity of 85%.
When the electrostatic tδ image was formed again in the same manner as described above after being left for three days, the contrast potential did not change much.

A conductive layer of about 1 μm was formed by sputtering Lulu.

Thereon, selenium containing 50 ppm of chlorine is vacuum-deposited to a thickness of 40 μm at a substrate temperature of 55° C. to form a charge transport layer. Furthermore, a 5e-Te alloy containing 20 parts tellurium and 1 part arsenic (As) was formed on this d-carrying layer.
A charge generation layer is formed by vacuum deposition to a thickness of 0.7μ,
Furthermore, an insulating layer is formed by vapor-depositing paraxylin to a thickness of 20 .mu.m. This photoreceptor was used as a sample of Reference Example 2, and this photoreceptor was path aged at 40° C. for 5 hours to prepare a sample of Example 2 of the present invention.

When these samples were tested under the same conditions as in Example 1, as shown in Table 1, the heat-aged actual gun example 2 exhibited a high contrast ratio of 470 V AC and 590 V DC.

I[) Reference Example 3 A S e -T e alloy containing 8 t of tellurium was deposited on a drum-shaped aluminum support at a substrate temperature of 60°C.
A photoconductive layer is formed by vacuum evaporation to a thickness of 50 μm, and a PIT film of 20 μm is adhered thereon to form a conventional type photoreceptor. A sample of Reference Example 3 was prepared after 1.5 months had elapsed after this photoreceptor was prepared.

When this sample was tested under the same conditions as in Example 1, only a low contrast potential of 6 nV and 170 V DC was obtained as shown in Table 11C.

Example 3 AI formed into a drum shape! Tellurium having a purity of 50% is vacuum deposited on the support to a thickness of about 0.5μ to form a conductive α layer, and 5e-Te containing 8% tellurium is deposited on the conductive layer at a substrate temperature of 60°C. The alloy is vacuum deposited to a thickness of 50 microns to form a single photoconductive layer.

Then, a 20 μm PET film is adhered onto this photoconductive layer to form an insulating layer, thereby producing the photoreceptor shown in FIG. 1 of the present invention. A sample of Example 3 was prepared after 1.5 months had elapsed after this photoreceptor was prepared.

When this sample was actually tested under the same conditions as Example 1, it showed a contrast potential of 300 V AC and 390 V DC as shown in Table 1. Although it is inferior to the data of Actual Gun Example 1, it is comparable to the reference example (conventional example). It can be seen that a higher contrast potential is shown in comparison.

From the results shown in the margins below, by using tellurium as the interfacial conductivity 14 with the photoconductive layer, the injection property during -order charging is improved, and the injection is inhibited during simultaneous light 1-quadrant exposure. The image quality is maintained well, and images with high contrast and high density can be obtained.

In addition, the generation of photocarriers is caused by charge generation, and the transport of photocarriers and the transport of injected carriers are shared by charge transport, which provides excellent photosensitivity.

And good I[!] with no residual potential or afterimage. Characteristics in J image are shown.

Furthermore, since the photoconductive layer is formed of a selenium-based vapor-deposited layer, it has features such as extremely superior moisture resistance compared to a pineapple-based photoreceptor.

It should be noted that the present invention is not limited to the above six practical examples, and can be implemented with various modifications without changing the gist.

In the above embodiment, an image forming process was described in which the photoreceptor was simultaneously charged # and image forming light was used; however, the present invention is not limited thereto.
After adding the negative corona layer as a primary layer as shown in
It is also possible to use an electrophotographic method in which a positive corona zone α is added and then a light image is exposed. In this case, JP-A-48-8
9737 performs primary band formation while irradiating the entire surface, but in the present invention with good implantation i/+, heavy pairs can be sufficiently formed on the top and bottom of the insulating layer even without irradiation on the entire surface during primary charging. be able to.

As described above, according to the present invention, high contrast and high concentration can be achieved by providing a tellurium conductor 1- on one surface of a selenium-based photoconductive layer and providing an insulating layer on the other surface. can be obtained (a child photoreceptor can be provided).

[Brief explanation of the drawing]

FIG. 1 is a structural diagram of Hatomoto of this invention, and FIG. 2 is a structural diagram of C showing one embodiment of this invention. 1... Support layer 2... Chilled conductive layer 3.
3... Selenium-based photoconductive layer 3a... Charge transport layer 3
b...Charge generating layer 4...Transparent insulating layer Figure 1: Showa year, month, day, Mr. Kazuo Wakasugi, Commissioner of the Japan Patent Office ■, Indication of the case, Patent Application No. 183847/1982, Name of the invention: Naruko Photoconductor 3. Relationship with Nakanobu, the person making the amendment Patent applicant (037) Olympus Optical Industry Co., Ltd. 4, Agent 5, Spontaneous amendment 7. Contents of the amendment (1) The scope of the claims of the patent application is amended as shown in the attached sheet. (2) The part "dielectric film" on page 2, line 12 of the present specification is corrected to "insulating layer." (3) The word "copying" on page 2, line 13 of the same specification is corrected to "formation." (4) "In the 15th and 16th lines of page 2 of the same specification,"
In general, the part ``during the latent image forming process'' is corrected to ``An electrophotographic photoreceptor consisting of a conductive layer, a photoconductive layer, and a layer is''. (5) From the 19th line to the last line of page 2 of the same specification, ``Simultaneous charging light image exposure...''The portion of the electrostatic latent image power month is replaced with ``simultaneous charging light image exposure, including full-surface exposure.'' The process creates an electrostatic latent image on the insulating layer.'' (6) From the last line of page 2 to the second line of page 3 of the same specification, the part [Usually, an electrophotographic photoreceptor is made by forming...] is deleted. (7) The part "It becomes high" in lines 9 and 10 of page 3 of the same specification is corrected to "It becomes high." (8) The part "Decreases." on page 3, line 10 to line 11 of the same specification is corrected to "decreases." (9) On page 3, line 14 of the same specification, the phrase ``As a result, of the photoconductive insulating layer'' is corrected to ``that is, of the photoreceptor.'' al In the same specification, on page 3, lines 15 and 16, the phrase "the effect is lost...the photosensitivity is simply" is corrected to "the effect is weak and only". all In the same specification, on page 4, lines 9 and 10, the phrase ``phosphor Zn CdS powder and photoconductive material ZnO powder'' is corrected to read ``reds powder, ZnO powder, etc.''. (L3 In the 4th line of the same specification, the ``zinc oxide film'' part is revised to ``binder-based photoreceptor.'' Correct it as rsUsJ. I Correct the part of “others” in lines 11 to 12 of page 5 of the same specification to read “others.” Explanation Lines 13 to 13 of page 5 of the same specification In line 14, the part "formed with resin... pasted" is corrected to "the transparent insulating layer 4 is formed with resin." (11, page 6, line 2 of the same specification) The “temporary” part of the eye is “-”
"Next," he corrected. αη The part "Selenium-based photoreceptor" on page 6, line 5 of the same specification is corrected to "Selenium-based photoconductive layer." tll The part "3b" on page 6, line 15, line 18, and page 7, line 4 of the same specification is corrected to "3a." (11 “3a” in the last line of page 6 and line 9 of page 7 of the same specification)
Correct the part as "3b". (a) On page 9, line 17 of the same specification, the part J in ``On a tellurium photoconductor that has been subjected to a process,'' is corrected to ``On a photoconductor that has a tellurium conductive layer that has only undergone a process.'' @) The part “predetermined” in the first line of page 10 of the same specification was changed to “
J of 1 month or more (!: Corrected. (22) Correct ro and 5MJ on page 11, line 8 of the same specification to "0.5μ". (23) Correct the same specification, page 16, line 8. Lines 12 and 14 “
Correct the "irradiation" part to "irradiation." (24) "Charge transport layer" on page 17, line 6 of the same specification is corrected as "charge generation layer J." (25) "Charge generation layer" on page 17, line 7 of the same specification The part is corrected to "charge transport layer." 2. Claims (1) A support layer, a conductive layer made of tellurium (Te) provided on one side of the support layer, and a selenium (Se)-based photoconductive layer provided on the conductive layer. An electrophotographic photoreceptor comprising a photoconductive layer made of a material and an insulating layer provided on the photoconductive layer. (2) The photoconductive layer is composed of a charge transport layer made of selenium or halogen-doped selenium, and a charge generation layer whose main elements are selenium and tellurium, and the charge transport layer is provided on the conductive layer side. An electrophotographic photoreceptor according to claim 1, characterized in that: (3) The photoconductive layer is a charge-generating layer containing at least 5 to 25 tellurium when a selenium-based charge transport layer containing 4000 PPM or less of halogen is deposited on the conductive layer to a thickness of 25 to 70 μm. 3. The electrophotographic photoreceptor according to claim 2, wherein the layer is deposited on the selenium-based charge transport layer to a thickness of 0.05 to 5 .mu.m. (4) The electrophotographic photoreceptor described in each of claims 1 to 3, wherein the photoconductive layer is deposited at a substrate temperature of 55 to 65°C. (5) The conductive layer and the photoconductive layer are formed by forming an insulating layer on the photoconductive layer or the photoconductive layer, and then heat-treating the conductive layer at a temperature of 30 to 65°C. Electrophotographic photoreceptors listed in each section.

Claims (5)

[Claims] (1) Support layer: a conductive layer made of tellurium (Te) provided on one surface of this support layer, and a photoconductive layer made of a selenium (Se)-based photoconductive material provided on this conductive layer. and an insulating layer provided on the photoconductive layer. (2) The photoconductive layer is composed of a charge transport layer made of selenium or halogen-doped selenium, and a charge generation layer whose main elements are selenium and tellurium, and the charge transport layer is provided in the conductive layer example. Claim 1: An electrophotographic photoreceptor according to the present invention. (3) The photoconductive layer is a selenium-based 4 charge transport layer containing 4000 PPM or less of halogen and deposited on the conductive layer to a thickness of 25 to 70 μm, and at least 50% tellurium.
The electrophotographic photoreceptor according to claim 2, characterized in that a charge generation layer containing ~25 µm is deposited on the selenium-based single charge transporting layer to a thickness of 0.05 to 5 μm. . (4) The electrophotographic photoreceptor described in each of claims 1 to 3, wherein the photoconductive layer is deposited at a substrate temperature of 55 to 65°C. (5) The conductive layer and the photoconductive layer are heat-treated at a temperature of 30 to 65° C. after forming the photoconductive layer or the insulating layer. The electrophotographic photoreceptor described above.