JPH02157764A - Production of electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To enhance sensitivity without deteriorating the film strength of a high-polymer layer by incorporating a stage for forming a straight chain high polymer contg. 0.01 to 0.4wt.% lubricant to a film and a stage for heating the film in an oxygen-contg. atmosphere into a stage for forming the high- polymer layer. CONSTITUTION:This electrophotographic sensitive body has a charge transfer layer 2 consisting of the high-polymer layer and a charge generating layer 3 contg. a photoconductor on a substrate 1 as the photosensitive body and the charge generating layer 3 has a free surface 4 on one side. The stage for forming this high-polymer layer has the stage for forming the straight chain high polymer contg. 0.01 to 0.4wt.% lubricant into the film and further the stage for heating the film in the oxygen-contg. atmosphere. Namely, the high- polymer layer which is formed as the film by adding the lubricant thereto is made into the film by thermally welding the same onto a conductive substrate and thereafter, the layer is treated in the oxygen-contg. atmosphere. The deterio ration in the electrophotographic characteristics is obviated in this way and the uniform high-sensitivity characteristic is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application The present invention relates to a method for manufacturing an electrophotographic photoreceptor used in electrophotographic copying machines, optical printers, and the like.

2. Description of the Related Art Among electrophotographic photoreceptors, functionally separated electrophotographic photoreceptors are widely used in which carrier generation by photoexcitation and carrier transport are made of different materials.

By selecting materials according to their functions in this way, we can provide excellent photoreceptors with highly sensitive electrophotographic properties. In addition, the optimal combination of materials has been studied from a wide variety of aspects, including mechanical strength, thermal stability, printing durability, environmental resistance, and manufacturing cost. Typical examples of such material combinations include amorphous selenium and polyvinylcarbazole, methyl squarate and triarylpyrazoline, Diane blue and oxadiazole, perylene pigment and oxadiazole, bisazo pigment and styriaanthracene, etc. There is.

On the other hand, from the viewpoint of productivity, by dispersing the above-mentioned photosensitive materials in a resin or an organic semiconductor,
Single-layer electrophotographic photoreceptors are also being developed.

However, functionally separated type photoreceptors or single-layer type photoreceptors using these organic materials have poor printing durability, and there are many problems that need to be solved in terms of lifespan and reliability.

A photoreceptor using such an organic material is a single-layer type photoreceptor with a photoconductive layer, Alternatively, it is necessary to uniformly form various layers depending on the electrophotographic process, such as a charge generation layer, a charge transport layer, and a surface layer to increase surface hardness in a functionally separated photoreceptor.

As a method for forming each of the above layers, a dip coating method, a spray coating method using a spray gun, a US spray coating method using ultrasonic waves, etc. are used, and a large capital investment is required.

In addition, attempts have been made to create functionally separated photoreceptors that use a highly hard inorganic charge generating layer on the surface to improve printing durability, but many of the inorganic charge generating layers that have excellent printing durability do not have sufficient characteristics. In order to maintain this, substrate heating is required, or a process such as plasma that effectively raises the surface temperature is required, so conventional organic charge transport layers, which have poor heat resistance, cannot produce photoreceptors with sufficient characteristics. The current situation is that this has not been obtained.

Under these circumstances, JP-A-55-90954 and JP-A-59353 disclose that PP is used as a charge transport layer.
5 (poly P-phenylene sulfide) has been proposed as an excellent material that can be manufactured at low cost by use as a charge transport layer in the form of a film or, in the latter case, as a vapor-deposited polymer film with high carrier mobility.

However, since the former PPS film usually has high resistance and low carrier mobility, it is necessary to devise some method to improve the mobility. Furthermore, since the latter film uses a vacuum evaporation method, the film forming speed is not sufficient and it is expensive for a photoreceptor using an organic material. Further, in both of the above films, the hardness of the film is low and it is not possible to obtain sufficient characteristics in terms of printing durability.

Under these circumstances, we conducted various studies to overcome the shortcomings of PPS films, such as low carrier mobility and carrier life.
A polymer layer mainly composed of a linear polymer layer having phenylene and a chalcogen element at the rose position (p-),
At a temperature of 25θ to 290′C in an atmosphere containing oxygen atoms for 0.2 to 50 hours, preferably 260 to 280°C
It has been found that by performing the treatment for 1 to 12 hours, the charge transport ability is dramatically improved.

Furthermore, polymers such as PPS can be made into films by extrusion or inflation methods, and by directly heat-sealing such polymer films to conductive substrates, it is possible to form polymers with a predetermined thickness. Since the layers can be easily formed, it is possible to provide a photoreceptor that is cheaper than ever before.

When such a polymer layer containing oxygen and having excellent charge transport ability is used as a charge transport layer in a function-separated electrophotographic photoreceptor, the photoconductive layer which is a charge generation layer is replaced with a photoconductive layer which is a charge transport layer. It can be obtained by laminating the above polymer layer.

By dispersing and mixing a photoconductor in this oxygen-containing polymer layer, a cheaper single-layer electrophotographic photoreceptor can be obtained.

These oxygen-containing polymer layers are hardened by heat treatment in an oxygen-containing atmosphere at high temperatures, and therefore have extremely excellent printing durability.

Problems to be Solved by the Invention It is possible to form a polymer layer whose main component is a linear polymer layer containing P-phenylene and a chalcogen element at the para position (p-), typified by PPS, into a film. At this time, an amorphous transparent film is obtained by melting the polymeric material at high temperature in an inert gas atmosphere, extruding it into a film, and rapidly cooling it.

By further stretching this film, a film having a predetermined thickness can be obtained.

At this time, an extruder with a linear extrusion opening such as a T-die or a circular extrusion opening is used, but if the friction during extrusion is large, the melted polymer may gel.
Otherwise, it adheres to the extrusion port, making it difficult to obtain a film with a uniform thickness.

Furthermore, when a single-layer electrophotographic photoreceptor is prepared by dispersing a photoconductor, a photoreceptor with excellent photosensitivity can be obtained by using a photosemiconductor with excellent heat resistance. At this time, it is necessary to obtain a highly sensitive photoreceptor without deteriorating the film strength of the polymer layer by dispersing the optical semiconductor in a mixed group.

Means for solving the problem At least has p-phenylene in the main chain direction, and
In the method for manufacturing an electrophotographic photoreceptor having a polymer layer mainly composed of a linear polymer having either 8sSe at the para position (p-), in the step of forming the polymer layer, 0.01
The method includes a step of forming a film from the linear polymer containing ~0.4% by weight of a lubricant, and a step of heating the film in an atmosphere containing oxygen.

In another invention, the step of forming the polymer layer includes 5 to 5
A method for producing an electrophotographic photoreceptor, comprising the steps of forming the linear polymer containing 50% by weight of a photoconductor into a film, and further heating the film in an atmosphere containing oxygen.

When forming into a film a polymer layer whose main component is a linear polymer layer containing P-phenylene and a chalcogen element at the para position (p-), as represented by PPS, the polymer layer The material is melted at high temperature in an inert gas atmosphere and an extruder with a linear extrusion port such as a T-die or a circular extrusion port is used, but if the friction during extrusion is large, the melted polymer may It is not easy to obtain a film with a uniform thickness because it causes gelation or adheres to the extrusion port.

Therefore, in order to reduce friction during extrusion and suppress gelation, a film can be formed with good reproducibility by adding a lubricant and extruding the melted polymer material.

However, since these lubricants segregate on the film surface,
If a large amount of lubricant is used, the lubricant will inhibit carrier injection from the charge generation layer when such a film is used as a charge transport layer in a functionally separated electrophotographic photoreceptor.

These polymer layers require oxygenation by heat treatment at high temperatures in oxygen. From this, in order to obtain a single-layer electrophotographic photoreceptor with excellent photosensitivity, it is desirable to mix and disperse a photosemiconductor with excellent heat resistance or oxidation resistance in the polymer layer. When a suitable amount of polymer is mixed, the photoconductor has the effect of preventing gelation of the polymer.

After the film-formed polymer layer is heat-sealed onto a conductive substrate and then processed in an oxygen-containing atmosphere, uniform electrophotographic properties can be obtained without deterioration of the electrophotographic properties. An electrophotographic photoreceptor having good characteristics can be provided at low cost.

The embodiment diagram schematically shows a cross section of an embodiment of a basic electrophotographic photoreceptor according to the present invention.

The electrophotographic photoreceptor shown in the figure has a charge transport moving layer 2 made of a polymer layer and a charge generation layer 3 containing a photoconductor layer on a support 1 as an electrophotographic photoreceptor, and the charge generation layer 3 includes a photoconductor layer. Occurrence B
3 has a free surface 4 on the one hand.

At this time, the thickness of the charge transport layer is 5 to 30 μm, preferably 1 μm.
0 to 20Ilrrh The thickness of the charge generation layer is 0.
The thickness may be 1-10 μm, preferably 0.2-2 μm.

Such an electrophotographic photoreceptor is manufactured by the following procedure.

l) Form the polymer layer into a film to a predetermined thickness.

2) Heat fusion on a conductive support.

3) Adding heated oxygen in an atmosphere with oxygen.

4) Form a photoconductive layer.

In the present invention, the conductive support may be made of a metal material, such as aluminum, or may be coated with a metal material.

In the present invention, in order to further improve the electrophotographic properties, in FIG. 1, between the support 1 and the charge transport layer 2,
Support! A barrier layer may be provided to effectively block carriers from being injected into the charge transport layer 2.

Materials for forming the barrier layer include A 1203, Bad
1Ba02, BedlB h O3, Ca0s ce
o2, Ce2O3, La2O3, DV2xs, Lu20
a, Cr2O5, Cub, Cu, 0. Fed,
PbO, Mg0sSrO1choa203, Tho
2, 2rO,, HfO2, 71%, TIO, SI
Metal oxides such as O@, GeO2, SIO, GeO or TAN, ANlSnNlNbNlTagl (iaN
Metal nitrides such as WC, 5nCXTiG, or metal carbides such as SIC, SIN, GeC1Ge
Insulators such as N and BClBN, and heat-resistant organic compounds such as polyimide, polyamideimide, and polyacrylonitrile are used.

In addition, in order to improve cleaning performance, abrasion resistance, or corona resistance, in Figures 1 and 2,
A surface coating layer is formed on the free surface 4. Suitable materials for the surface coating layer include Sl, 0l-xs 5lxC
1-x, 5lxN+-x, Ge*0+-x, GexC+
-x, ce.

NI-++, ByNl-x, B*CI-x,
Examples include inorganic substances such as AIINI-x (O x x 1), carbon, and layers containing hydrogen or halogen.

At this time, a predetermined amount of N of an electron-accepting additive may be mixed in advance.

The electron acceptors to be added include 1,3-dibenthoquinone, p-benzenequinone N, 2.4.7-dolinitroflubinone (TNF), and 2.5-dibenzene.
-p-hensonoquinone, 2,4,5.7-titranitroflupanone, p-chloranil, O-chloranil, 7,7,8.8-tetracyanoquinoxymethane, 2,3-chloranil ', Q[+-5,8-disi r/-
At least one organic material such as p-benzoquinone can be used.

As the inorganic optical semiconductor of the charge generation layer, As5Set, 5
A chalcogen-based amorphous layer such as e(Te) was used. As2S
e3 was formed into a film by vacuum evaporation. At this time, 60 to 1
The substrate temperature was controlled at 20°C. In addition, in order to have high sensitivity to visible light or near infrared light, As-
A single layer of 5e-Te or a stacked layer thereof can also be used as the photoconductive layer.

The photoconductor material dispersed in a mixed number in the polymer layer has excellent heat resistance Cd51CdS+-xsex (0<x<1)
, TlO2, ZnO, etc., or a powder obtained by adding a sensitizing element to these powders can be mixed into a polymer and formed into a film.

To form a polymer into a film, fill the hopper of an extruder with a polymer material with a high degree of polymerization, and after purging with nitrogen,
Heat to 10"C and dissolve. This dissolved polymer is
It was extruded from a T-die with a slit width of 250 mm and a slit width of 0.3+am, and cast onto a metal drum cooled to room temperature with water to obtain an amorphous polymer layer.

This amorphous polymer film was adjusted to the required thickness by stretching.

When extruding this polymer, a metal soap lubricant such as calcium stearate, zinc stearate, lead stearate, cadmium stearate, etc. is added at the same time as the polymer material, or photoconductor powder is required. 1. A linear polymer layer film was obtained by mixing and dispersing in the polymer layer.

After forming the film-formed polymer layer by heat-sealing it onto a conductive substrate, it is heated at a temperature of 250 to 290°C in an oxygen-friendly atmosphere for 0.2 to 50 hours. Preferably, by performing the treatment at 2B[theta] to 280[deg.] C. for 1 to 12 hours, an electrophotographic photoreceptor having uniform and good properties can be provided at a low cost without deteriorating the electrophotographic properties.

Further, by mixing and dispersing 5 to 25% by weight of inorganic photoconductor crystal powder in the polymer layer, a single-layer electrophotographic photoreceptor with high photosensitivity can be provided at a low cost.

In addition, by mixing and dispersing 25 to 50% by weight of inorganic photoconductor crystal powder into a polymer layer as a charge generation layer, and further fusing the polymer layer as a charge transport layer, conventional coating,
It is possible to provide an inexpensive and long-life electrophotographic photoreceptor without requiring large equipment such as vapor deposition.

Furthermore, these polymer layers are thermally cured by heat treatment during oxygen addition, and therefore have excellent stability and printing durability.

Example 1 As a lubricant, 0 to 1% by weight of calcium stearate was mixed with PPS, which is a representative linear polymer, to obtain a PPS film. Several tens of meters of PPS film that does not contain lubricant
From the time of extrusion, film thickness irregularities like "streaks" that coincided with the extrusion direction appeared on the film.

On the other hand, in the case of rich molecules mixed with a lubricant, no remarkable effect was observed at 0.01% by weight or less, an effect was seen from 0.01% by weight, and almost no film thickness unevenness could be observed at 0.05% by weight. Ta.

The film-shaped PPS obtained in this way was pasted on a mirror-polished aluminum substrate, and a tetrafluoroethylene resin sheet was placed on the film as a release agent.
The substrate is placed as a weight, heated in a heat treatment furnace, and PP
The S film was fused onto an aluminum substrate.

The heating temperature is 285°C, which is the melting temperature of PPS,
The heating atmosphere is the atmosphere.

After taking out the substrate from the heat treatment furnace, the fluororesin sheet was removed, placed in the heat treatment furnace again, and heat treated in an oxygen atmosphere. The heating temperature was controlled within the range of 260°C to 285°C, and the heat treatment time was constant for 6 hours.

After this treatment, the thickness of the PPS film was set to 8 to 15 μ-. This layer is used as a charge transport layer, and a Se (8 wt% Te) chalcogen compound is added as a charge generation layer by vacuum evaporation.
．． 05 to 5.0 μm was laminated to form an electrophotographic photoreceptor.

When these electrophotographic photoreceptors were corona charged with G and QkV, +to
It was possible to obtain a surface potential of oov, and when exposed to white light, the half-decrease exposure amount was ~3.01x·S or less, showing very excellent electrophotographic properties.

However, as the amount of lubricant increased, an increase in residual potential was observed. This is due to the presence of a large amount of lubricant on the surface of the extruded film.

In other words, when the carriers generated by photoexcitation in the chalcogen-based inorganic photosemiconductor that is the charge generation layer are injected into the oxygen-added PPS that is the charge transport layer, the segregated lubricant reduces the injection efficiency. it is conceivable that.

If the amount of lubricant added is 0.4% by weight or less, the residual potential will also decrease.
However, if the amount added is greater than 100V, the residual potential increases, and the characteristics of the electrophotographic photoreceptor with 0.6% and 1% addition by weight are +200V and +400V, respectively, in terms of residual potential.
This has increased.

Further, when the composition contained in the polymer layer of this electrophotographic photoreceptor was analyzed, the composition ratio of C atoms to C atoms contained in the charge transport layer changed as a result of heat treatment in oxygen.
An increase of 1 to 5 at-% was confirmed.

Similar results were obtained with other lubricants such as zinc stearate, lead stearate, and cadmium stearate.

Example 2 Next, as a second example, a PPS film (denoted as PP5(0)) in which a film containing 0.1% by weight of lubricant was extruded in the same process as in Example 1 and further subjected to oxygen addition treatment. Furthermore, p-chloride as an electron acceptor is added to the above pps.
(o) Put the film into a sealed container at the same time and heat it under vacuum or normal pressure to vaporize the electron-withdrawing material and
．． The film was doped to a concentration of 0.05 to 1.0%.

On this charge transport layer, ASzSe3, which is a chalcogen-based inorganic photoconductive layer, is placed as a charge generation layer at a substrate heating temperature of 140.
The film was formed by vacuum evaporation to a thickness of about 0.8 μm at a temperature of 0.03° C. to obtain an electrophotographic photoreceptor.

When these electrophotographic photoreceptors were charged to a surface potential of +600 V and exposed to light of 500 nm, the half-potential exposure m was 0.51 x-sec in terms of illuminance, showing very high sensitivity.

Example 3 Next, as a third example, PPS film was prepared by further mixing and dispersing inorganic photoconductor crystal powder into an oxygenated PPS film.
A single-layer electrophotographic photoreceptor was prototyped by extruding the PS film.

CdS crystal powder with a diameter of 1 to 2 μm was used as the inorganic photoconductor crystal powder. This crystal powder is applied to polymers at 265%
A polymer film dispersed in a mixing chamber to 75% by weight was extruded in the same manner as in Example 1 to obtain an amorphous film.

When this amorphous film was stretched to a predetermined film thickness, all of the films in which more than 50% by weight of the above-mentioned mixed amounts were mixed broke midway, making it impossible to control the film thickness.

Furthermore, if the film is mixed in a larger amount than this, the mechanical strength of the film decreases, and the film may break during operation.

Example 1
Similarly, after heat-sealing onto a conductive support, oxygen addition treatment was performed to obtain a single-layer electrophotographic photoreceptor.

Among these, when an electrophotographic photoreceptor with a film thickness of 12 ± 2 μm was charged with a corona voltage of 10 kV, 5 to 2
5% by weight photoreceptor, charged to a surface potential of -+000 to eoov,
When exposed to white light, the half-reduced potential exposure amount was 3 to 71X
・S and good characteristics could be obtained.

On the other hand, for a film with a weight of 25 to 50%, the surface potential was -
It was not possible to obtain a sufficient potential below eoov.

When such a photoconductor is dispersed, no lubricant is particularly required for forming a film, probably because a suitable amount of the photoconductor has the effect of preventing gelation of the PPS polymer.

Example 4 In Example 3, the crystal powder of the inorganic photoconductor, which could not obtain a sufficient surface potential with the single-layer electrophotographic photoreceptor, was
A polymer layer containing 5 to 50% by weight was further superimposed and fused with a polymer layer containing no crystal powder to obtain a functionally separated photoreceptor.

Oxygen addition treatment was performed in the same manner as in Example 3 above, and 6 kV corona voltage charging treatment was performed, followed by exposure to white light.

All of these function-separated electrophotographic photoreceptors have a surface potential of -1ooov or more, and a half-potential exposure amount of 2
Good characteristics of ~31X-3 were obtained.

In addition, 25% by weight was added to the polymer layer that does not contain the above crystalline powder.
Good results were obtained even when the layer was replaced with an ungrooved layer.

Example 5 In Example 3, Cd55. The same amount of powder eSei, a was formed into a film in the same process to obtain a single-layer electrophotographic photoreceptor.

When this photoreceptor was similarly charged with a corona potential of -8 kV, a surface potential of -500 to 100 OV could be obtained, and when exposed to white light, the potential was halved with an exposure amount of 0.5 to 1. A high sensitivity of .51x-s could be obtained.

In the case of this photoconductor, this is not only due to a shift in the light absorption wavelength to longer wavelengths, but also due to an increase in the efficiency of charge injection from the photoconductor into the polymer layer. This effect is due to Cd
';H-, Sex's 0.2< x <0. Obtained in G.

In Examples 3 to 5, the average particle size is preferably 3 μm or less in order to uniformly disperse the inorganic optical semiconductor in the polymer layer.

Effects of the Invention According to the present invention, P-phenylene is added and 5x is added to the para position.
0.0 to a linear polymer having at least one of Set. By adding a lubricant in an amount of 1 to 0.4% by weight, it becomes possible to form a film by extrusion or the like with good reproducibility. This polymer layer is heat-sealed onto a conductive support, and then
By incorporating atoms, the charge transport ability of the polymer layer can be dramatically improved.

By using such a polymer layer as the charge transport layer of a functionally separated electrophotographic photoreceptor, it is possible to obtain an electrophotographic photoreceptor with high sensitivity and low residual potential at a lower cost than ever before without requiring large capital investment. did it.

Furthermore, by mixing and dispersing inorganic photoconductor crystal powder of 5 to 25% polymerization in the linear polymer layer, a single-layer electrophotographic photoreceptor with high photosensitivity can be provided at a low cost. .

[Brief explanation of the drawing]

The figure is a sectional view of an electrophotographic photoreceptor in an example of the present invention. 1...Support, 2...Charge transport layer, 3
...charge generation layer, 4...free surface.

Claims (5)

[Claims] (1) At least has p-phenylene in the main chain direction,
Further, in the method for manufacturing an electrophotographic photoreceptor having a polymer layer mainly composed of a linear polymer having either S or Se at the para position (p-), the step of forming the polymer layer comprises: 0
．． A method for producing an electrophotographic photoreceptor, comprising the steps of forming the linear polymer containing 01 to 0.4% by weight of a lubricant into a film, and further heating the film in an atmosphere containing oxygen. (2) At least has p-phenylene in the main chain direction,
Further, in the method for manufacturing an electrophotographic photoreceptor having a polymer layer mainly composed of a linear polymer having either S or Se at the para position (p-), the step of forming the polymer layer comprises: 5
A method for producing an electrophotographic photoreceptor, comprising the steps of forming the linear polymer containing ~50% by weight of the photoconductor into a film, and further heating the film in an atmosphere containing oxygen. (3) Claim 2 characterized in that a single polymer layer containing 5 to 25% by weight of a photoconductor is formed in a linear polymer.
A method for manufacturing an electrophotographic photoreceptor as described in . (4) A polymer layer containing 25 to 50% by weight of a photoconductor in a linear polymer, and two polymer layers containing a smaller amount of photoconductor than the photoconductor contained in the above polymer layer. 3. The method of manufacturing an electrophotographic photoreceptor according to claim 2, wherein the electrophotographic photoreceptor is formed by laminating more than one layer. (5) The method for producing an electrophotographic photoreceptor according to claim 1 or 2, comprising the step of performing treatment at a temperature of 250 to 290° C. for 0.2 to 50 hours in an atmosphere containing oxygen atoms.