JPH03152548A - Production of photosensitive body - Google Patents

Abstract

PURPOSE:To prevent the degradation and fluctuation in surface potential by subjecting a photosensitive layer to a bombarding treatment before the layer is coated with a vacuum thin film. CONSTITUTION:The oxide film formed on the surface of the surface protective layer is physically struck by ion bombardment and is detached from the surface. The fresh photosensitive layer which is not oxidized appears thereafter. He, Ar, H2, N2, O2, N2O, etc., which themselves do not induce a film forming reaction are usable as the inert gas for the bombarding treatment. The surface protective layer (vacuum thin film) is formed with good adhesiveness by various methods, such as plasma CVD method, photo CVD method, thermal CVD method, sputtering method, vapor deposition method, and ion plating method, on the surface of the photosensitive layer having the surface subjected to the bombarding treatment in such a manner. The good photosensitive body which is free from the degradation in surface potential, the fluctuation in the surface potential, etc., is obtd. in this way.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a method for producing a photoreceptor having a protective layer on its surface.

BACKGROUND ART Photoreceptors are generally manufactured by forming a photosensitive layer on a conductive substrate and then forming a surface protective layer.

Ideally, the surface protective layer should be formed on the surface immediately after forming the photosensitive layer, but in reality, to simplify the manufacturing process and due to equipment problems, it is preferable to form only the photosensitive layer. Generally, it is produced in large quantities at one time and then subjected to the process of forming a surface protective layer such as an amorphous carbon film.
The photosensitive layer is often stored for several days to one month (this storage time is referred to as "starting time").

After formation, the surface of the photosensitive layer is oxidized by oxygen in the atmosphere over time. When attempting to provide a protective layer, such as an amorphous carbon film, on the surface of a photosensitive layer on which such an oxide film is formed, the surface protective layer may peel off due to poor adhesion between the oxide film surface and the protective layer. It will happen. According to the experience of the present inventors, this phenomenon already occurs in the photosensitive layer that has been coated for one day.

In order to remove such an oxide film, conventionally, the surface of the photosensitive layer has been washed with a general halogen-based cleaning solvent typified by Freon. In this way, the oxide film on the organic photosensitive layer is certainly removed and the adhesion between the photosensitive layer and the surface protective layer is ensured, but the organic photosensitive layer is deteriorated and the surface potential decreases and becomes uneven. There is a problem with doing so. In the case of an inorganic photosensitive layer, the oxide film cannot be effectively removed even under fairly severe cleaning conditions, and the adhesion between the photosensitive layer and the surface protective layer cannot be ensured.

In addition, an electrophotographic photoreceptor in which the surface protective layer is formed of a vacuum thin film, for example, JP-A-62-100766.62-294
258.51-139340.4935036.48-
128732.49-122337.58-59454
．． 61117562.58i52255.63-979
62, etc., but before forming a vacuum thin film on the surface of a photosensitive layer that has been stored for a long time, in order to ensure adhesion,
There is no mention or suggestion that the coated photosensitive layer needs to be cleaned.

Problems to be Solved by the Invention The present invention has been made in view of the above-mentioned circumstances. It is an object of the present invention to provide a method for manufacturing a photoreceptor that is free from decreases and variations in temperature.

This objective is achieved by bombarding the surface of the photosensitive layer.

Means for Solving the Problems The present invention is a method for manufacturing a photoreceptor in which a vacuum thin film is provided as a surface protective layer on a photosensitive layer, characterized in that the photosensitive layer is subjected to bombardment treatment before being covered with the vacuum thin film. This invention relates to a method for manufacturing a photoreceptor.

In the present invention, bombardment processing means processing the photosensitive layer by bombarding the surface of the photosensitive layer with an inert gas in an ionized state, and the oxide film formed on the surface of the photosensitive layer is It is physically struck by ion bombardment and detached from the surface, leaving behind a fresh, unoxidized photosensitive layer.

Ionic species having such an action can be easily obtained by converting an inert gas into a plasma.

In order to bombard the surface of the photosensitive layer with plasma-formed ion species, pressure, frequency, and power may be appropriately selected and combined as bombardment processing conditions.

More effective bombardment is achieved under conditions of low pressure, low frequency, and high power.

Further, if the substrate temperature of the photosensitive layer is increased, atoms on the surface are more likely to be detached, and the bombardment effect becomes higher.

The longer the bombardment time, the greater the bombardment effect.

The inert gas for bombardment treatment is He.

It is possible to use materials such as Ar, H, N7.02, N20, etc. that do not cause a film formation reaction.

In bombardment treatment, the oxidized layer on the surface of the photosensitive layer is generally removed by physical collision. However, when the surface of the organic photosensitive layer is bombarded with oxygen plasma using 02 as an inert gas, the surface of the photosensitive layer is removed. Carbon (C) and hydrogen (11), which are the atoms that form Co, react with oxygen plasma ions, forming Co,...
It is thought that a chemical reaction removal effect can also be obtained in which the substance is removed as a gas such as 11□0, and the bombardment effect becomes even higher.

The photosensitive layer to which the ion bombardment treatment of the present invention is effective is not particularly limited, and can be applied to both organic and inorganic photosensitive layers.

The organic photosensitive layer may contain charge generating substances such as phthalocyanine pigments, azo pigments, perylene pigments, etc. and charge transporting substances such as triphenylmethane compounds, triphenylamine compounds, hydrazone compounds, styryl compounds, pyrazoline compounds, oxazole, etc. compound, oxadiazole compound, etc., to a binding material such as polyester,
Polyvinyl Butyler J-Tsu A single-layer structure that is dispersed and coated on polycarbonate, polyarylate, styrene acrylic, etc., or a charge generation substance and a charge transport substance that are dispersed and coated in separate layers to separate charge generation and charge transport functions. The present invention can be applied to any type of photosensitive layer having a function-separated structure (the order of lamination may be arbitrary), and of course, in addition to the resin-dispersed type described above, charge-generating substances or charge-generating materials may also be used. It may be a photosensitive layer made of a vapor deposited layer or the like made of the transport substance itself.

The present invention can be applied to various inorganic photosensitive layers in which oxidative deterioration is a problem, such as amorphous selenium, amorphous silicon, and amorphous carbon.

A surface protective layer ( A vacuum thin film) can be formed with good adhesion, and the resulting photoreceptor can be of good quality without a decrease in surface potential or variation in surface potential.

The present invention will be further explained below with reference to Examples.

Preparation of Inukoshi peeling photosensitive layers (a), (b) and (c) An organic photosensitive layer (abbreviated as aXoPC(a)) and an amorphous silicon based photosensitive layer (bXa-5i(b)) were prepared as follows. ) and 1
3) and amorphous selenium photosensitive layer (cXaSe(
c) and abbreviated) were produced.

Among these photosensitive layers, the photosensitive layer (a) is for negative charging, and the photosensitive layers (b) and (c) are for positive charging.

Preparation of organic photosensitive layer (a) A mixed solution of bisazo pigment chlorodiane blue (CD8 weight part), polyester resin (manufactured by Toyobo Co., Ltd.; V-200) 1 weight part, and cyclohexanone 100 weight parts was mixed with a sand grinder for 13 minutes. This dispersion was applied onto a cylindrical aluminum substrate with a diameter of 80 mm and a length of 340 mm using a commonly used dipping device, and dried to form a charge generation layer with a thickness of 0.3 μm.

Separately, 1 part by weight of 4-diethylaminobenzaldehyde diphenylhydrazone (DEH) and 1 part by weight of polycarbonate (manufactured by Ondai Kasei Co., Ltd., Ni-1300) were added to THF.
This solution was applied onto the charge generation layer and dried to form a charge transport layer having a thickness of 15 μm after drying to obtain an organic photosensitive layer (a).

Preparation of amorphous silicon-based (b) photosensitive layer Using a commonly used plasma-CVD apparatus, a layer of 80 mm in diameter x 340 mm in length was prepared.
An a-3i:C based undercoat layer and an a-5i sensitive photosensitive layer were provided on a cylindrical aluminum substrate having a diameter of 1.5 mm. The film forming conditions were as follows.

(i) a-3i: C-based undercoat layer Raw material gas and SiH4 Gas flow rate H2 C, H2 Hydrogen to 11000pp Diluted B,H.

Substrate/electrode spacing 40mm Power frequency 13.56MHz 1! Power 250W Vacuum degree Q, 8 Torr Substrate temperature 200℃ Discharge time 3 minutes Film thickness 2500A 120 sec 600 sec 60 sec 3 Q seem Composition Si: approx. 42 atomic% C: approx. 36 atomic% l(: approx. 22 atomic% B: approx. 230 atomic ppm (ii) A-5i-based photosensitive raw material gas and SiH < 180 sec Gas flow rate H2600 sec 020 , 4 sec B2H6 diluted 3 sec to 1100 pp with hydrogen Substrate/electrode spacing 40 mm Power supply frequency 13.56 MHz Discharge power 300 W Degree of vacuum 1. 0 Torr Substrate temperature 200°C Discharge time 4 hours Film thickness 23 μm Composition Si: approx. 79 atomic% H: approx. 21 atomic% 0: approx. Using resistance heating vapor deposition method, diameter 80+++m x length 340mm
An As2Se photosensitive layer was provided on a cylindrical aluminum substrate.

Here, the pressure during film formation was 2 X I O' Torr, the deposition rate was 30 persons/sec, and the thickness of the photosensitive layer formed was 50 μm.

Bombardment Treatment and Formation of Surface Protective Layer The photosensitive layer obtained as described above was stored in an environment of 20° C. and 65% for 30 days, and then subjected to bombardment treatment as described below to form a surface protective layer.

The organic photosensitive layer (a) was placed in a commonly used P-CVD apparatus, and the inside of the apparatus was evacuated to about 10-5 Torr. Next, the pressure inside the apparatus was adjusted to Q, 2 Torr while flowing the argon gas into the apparatus at a rate of 100 sec.

When the pressure becomes constant, apply a frequency of 80KHz to the electrode.
, 150 W of low frequency power was applied, and Ar plasma bombardment was performed for 1 minute. At this time, the substrate temperature was 50°C.

After the bombardment process, the photosensitive layer is taken out of the vacuum system,
Next, an amorphous carbon film (
A surface protective layer consisting of a-C) film was formed as follows. After the pretreatment, the organic photosensitive layer (a) is processed by conventional P-CV.
It was set in apparatus D, and the inside of the apparatus was evacuated to about IO-'Torr. Next, while flowing hydrogen gas at a rate of 300 sec and butadiene gas at a rate of 3 Q sccm,
The pressure inside the apparatus was adjusted to 0.3 Torr. When the pressure becomes constant, apply a frequency of 3QKHz% 15 to the electrode.
A low frequency power of 0 W was applied, and the a-C film was formed for 3 minutes. At this time, the substrate temperature was 50°C. The thickness of the obtained a-C film was 0.96 μm. The time from the end of bombardment to the start of surface protective layer formation was within 3 hours by performing the air supply and exhaust process quickly.

The conditions for the above bombardment treatment and surface protective layer formation are summarized in Table 1.

The photosensitive layers (b) and (C) were also subjected to bombardment treatment and surface protective layers were formed in the same manner as above under the conditions shown in the table, and the results are summarized in Table 1 as examples.

Furthermore, regarding the photosensitive layer (a), a
- Instead of the C film, a commonly used sputtering device was used under the following conditions: Target: AQ203 Substrate temperature: 50°C Discharge interval: 50 mm (distance between target and substrate) Vacuum degree: 2 X I O"" Torr discharge gas
:Ar Discharge power: 2. OKW Discharge frequency: 13.56 MHz Discharge time: 12 minutes 06 layer film thickness: A photoreceptor with a thin film of AQ=O1 was prepared by 1800 people and subjected to evaluation.

As for the photosensitive layer (a), in place of the a-C film as a surface protective layer, a conventional vacuum heating evaporation apparatus was used under the following conditions: evaporation source: 510°, substrate temperature: 50°. C Port temperature + 1200°C Vacuum degree: 8 X I O-5Torr Vapor deposition time
: 5 minutes 06 layer film thickness: A photoreceptor provided with a thin SiO film was prepared by 1300 people and subjected to evaluation.

Insect rod 1 The photosensitive layers (a) to (C) are Freon 1 represented by the following structural formula.
13; was used for washing.

The cleaning tank was made of stainless steel and had an internal volume of 30 (vertical) x 30 (horizontal) x 50 (height to liquid level) CI++''.

An ultrasonic oscillator with an output of 500 W was attached to the cleaning tank (Comparative Examples 7 to 12).

Measurement of photoreceptor surface potential (before formation of surface protective layer) As shown in Fig. 1, the photosensitive drum (IO) before formation of the surface protective layer was installed, and the peripheral speed was 130++o++/
Rotated in sec. High voltage RCI 2XMODEL6
Electric power was supplied from a 10A (manufactured by TREK) to a corotron charger (13), and the surface of the photosensitive layer was charged to 500μ. The charging potential was measured using a surface electrometer (14XMODEL36
2A, manufactured by TREK), and the current apA at that time was read with an ammeter (IJ).

As shown in FIG. 2, surface electrometers were installed at three locations in the longitudinal direction of the drum, and the potentials at locations corresponding to the top, middle, and bottom of the drum were simultaneously measured. In addition, the reading a [μA] of the above-mentioned ammeter is 3
In all experiments, the variation in surface potential at the top, middle, and bottom of each drum was within 157. Finally, the charged charge is removed using an eraser lamp (tungsten lamp, color temperature 2800°, 40 [1ux-sec]).
was irradiated and erased.

(After forming the surface protective layer) Next, attach the photosensitive drum on which the surface protective layer has been formed, adjust the output of the charger (3) so that the reading value of the ammeter (11) becomes a[μA1 again, Read the surface potential at each position on the top, middle, and bottom of the drum using two surface electrometers (14).
The evaluation results were shown using the following symbols according to the range of decrease from the initial average value of surface potential of 500V.

(Variation evaluation) Evaluation results are shown according to the difference between the maximum value and the minimum value of the surface potential fluctuation within the circumference. The surface potential has a representative value that is an intermediate value between the maximum value and the minimum value.

The three parts (Fig. 2) were subjected to a JIs-5400 standard board test.

■Longitudinal direction. Regarding dispersion, evaluate the maximum and minimum values in the same way for the top, middle, and bottom three locations.

Adhesive Evaluation The adhesion of the surface protective layer was evaluated by visually observing the resulting copied image by mounting the obtained photoreceptor (with protective layer) on an actual copying machine.

As a copying machine, EP490Z (manufactured by Minolta) was used. However, the photoreceptors using the photosensitive layers (b) and (c) were modified so that the charging and developing polarities were reversed.

O indicates a good image, △ indicates an image with no practical problems, × indicates an unsuitable image.

Table 1 summarizes the evaluation results for each photosensitive layer.

(Hereinafter, blank space) In Example 1-13, the organic photosensitive layer (a) was pretreated by changing the Ar bombardment conditions, and then an a-C film was formed by plasma-CVD as a surface protective layer. This is an example. Regarding bombardment conditions in which the substrate temperature was changed in a similar experiment, the amorphous silicon photosensitive layer (b)
This was carried out in Examples 30 to 32 using .

From the results of Examples 1 to 13 and Examples 30 to 32,
It is understood that the adhesion of the a-C film is ensured without compromising the electrostatic properties.

Bombardment time is less than 2 minutes (compare Example 1 with 2)
If the bombardment power is lower than 100 W (compare Example 5 with 6), if the bombardment frequency is higher than l MHz (compare Example 8 with 9), then the bombardment pressure is I
If higher than Torr (compare Examples 11 and 12),
Substrate temperature is lower than 50°C (compare Example 30 with 3)
It is understood that although there are some cases in which the adhesion is slightly poor, there is no problem in practical use, and the bombardment treatment produces superior results compared to Comparative Examples 1 to 2I.

From Examples 14 to 25, it is understood that equivalent results can be obtained even if the bombardment gas is changed to something other than argon, such as helium, oxygen, or nitrogen. In particular, it can be seen that when the organic photosensitive layer was bombarded with oxygen, the adhesion was extremely good compared to Example 1114.18, which was bombarded under the same conditions except for changing the bombardment gas. .

From Examples 26 to 29 and 33 to 36, it is understood that the same results as in Example 1 can be obtained even if the photosensitive layer to be bombarded is changed to a material other than organic.

From Examples 37 to 48, a-C films produced under different conditions and AQ20 produced using different manufacturing methods were used as surface protective layers.
It is understood that the same results as in Example 1 can be obtained even when three SiO films manufactured using different manufacturing methods are provided.

From Examples 49 to 54, it was found that the bombardment treatment applied to the oxygen plasma organic photosensitive layer had extremely good adhesion.
It is understood that the same results can be obtained for values other than C1[I.

In Comparative Example 1-12, a vacuum thin film was formed as a surface protective layer on the photosensitive layers (a) to (c) to be used in the examples of the present invention after removing the oxide film by a cleaning method. This is an example. As cleaning agents have excellent cleaning ability,
- Freon-based cleaning agents often used for boat fishing (Freon 113
)It was used.

Comparative Examples 1 to 6 are examples in which organic photosensitive layers (a) were used. In the case of an organic photosensitive layer, since its surface is soluble in a solvent, it can be seen that the oxide film is removed and the adhesion is improved.

However, if the time of immersion in the solvent is too long (immersion for 2 minutes), the surface potential after coating will decrease, and as a result, Comparative Examples 4 to 6 are ranked as ×. Since a decrease in image density due to this decrease in surface potential was also observed on the image, the image evaluation rank was expressed as ×.

On the other hand, if the time of immersion in the solvent is too short (1 minute immersion), dripping may occur during cleaning, resulting in
That is, a difference in surface potential occurs between the portion where the solvent has been attached to the photoreceptor surface for a long time and the portion where it has not been attached, and V. The variation becomes larger. V in Comparative Examples 1 to 3
. This is the reason why the dispersion evaluation rank is ×. Image noise with very noticeable drip-like shading also occurred on the image, so the image evaluation rank was expressed as ×.

■. As for the variation, if the immersion time in the solvent is long, the rank is △. This is the case from the center to the bottom of the drum in Comparative Examples 4 to 6. This is because the difference in variation is only observed to be small because Vo becomes low. The area from the center to the bottom of the drum is cleaned using the immersion method, so the time difference between immersing it in the solvent and pulling it up means that the area is in contact with the solvent for a longer period of time than the upper part.

In Comparative Examples 7 to 12, similar cleaning methods were attempted for amorphous silicon-based and amorphous selenium-based inorganic photoreceptors, but they were immersed for a long time and ultrasonic waves were applied during that time. Despite intensive cleaning, adhesion could not be ensured, and Comparative Example 13 without pretreatment
The results were the same as those for ~21. From this, it is understood that the oxide film cannot be removed by cleaning from inorganic photoreceptors.

In Comparative Examples 13 to 21, photosensitive layers (a) to (C) (stored for 30 days after photosensitive layer preparation) to be used in the examples of the present invention were subjected to plasma treatment without surface treatment.
A-C surface protective layer by CVD method, A1220 by sputtering method. , an SiO film was formed as a surface protective layer by vapor deposition.

As shown in the adhesion evaluation, the adhesion ranks are all ×,
It is understood that the oxide film caused by long-term storage has an adverse effect on the adhesion of the vacuum thin film intended to be provided as a surface protective layer. Needless to say, if the surface protective layer is not adhered, the original purpose of the surface protective layer, which is to extend the life of the photoreceptor, cannot be achieved.

In addition, natural peeling occurred without the need to perform a substrate inspection, resulting in a difference in surface potential between areas with and without a surface protective layer, and the V0 variation evaluation was ranked △, although there was no practical problem. child.

In image evaluation, peeled pieces of the vacuum thin film adhere to the copied image, or peeled pieces get mixed into the developing device and get caught between the height regulating plate and the developing sleeve, or between the photoreceptor and the developing sleeve, resulting in problems in the developing process. This resulted in very unfavorable results such as inhibiting the flow of the agent and causing so-called development defects. Image evaluation rank X indicates this.

Effects of the Invention It has become possible to form a highly adhesive vacuum thin film as a photoreceptor surface protective layer without reducing the surface potential of the photoreceptor or causing variations in surface potential.

[Brief explanation of the drawing]

FIG. 1 shows an example of a schematic configuration of a photoconductor surface potential measuring device. FIG. 2 is a diagram showing a portion of the photoreceptor where the surface potential is measured.

Claims (1)

[Claims] 1. A method for manufacturing a photoreceptor in which a vacuum thin film is provided as a surface protective layer on a photosensitive layer, wherein the photoreceptor layer is subjected to bombardment treatment before being covered with the vacuum thin film. manufacturing method. 2. The method for producing a photoreceptor according to claim 1, wherein the photosensitive layer is an organic photosensitive layer containing at least a charge-generating material and a charge-transporting material. 3. The method for manufacturing a photoreceptor according to claim 1, wherein the vacuum thin film is an amorphous carbon film produced by a plasma CVD method. 4. The method for producing a photoreceptor according to claim 1 or 2, wherein the bombardment treatment is performed with a gas containing oxygen atoms.