JP2023074262A - Manufacturing method of electro-photographic photoreceptor, and electro-photographic photoreceptor - Google Patents

Abstract

To provide a manufacturing method of an electro-photographic photoreceptor having high wear resistance, good electrical characteristics and achieving higher picture quality for a long time, and the electro-photographic photoreceptor.SOLUTION: The manufacturing method of an electro-photographic photoreceptor is for manufacturing an electro-photographic photoreceptor including at least a photosensitive layer and a protective layer on a conductive support medium, and includes the steps of: forming a coating film as protective layer using coating liquid containing a polymerizable compound; and after the coating film is formed, irradiating the coating film with light energy using a light-emitting diode as light source for curing to form a protective layer. The light energy satisfies the condition represented by the following formula (I). Formula (I): 500 mW/cm2<peak radiation illuminance on photoreceptor≤25000 mW/cm2.SELECTED DRAWING: Figure 1

Description

The present invention relates to a method for producing an electrophotographic photoreceptor and an electrophotographic photoreceptor, and in particular, an electrophotographic photoreceptor that has high abrasion resistance, good electrical characteristics, and can realize high image quality over a long period of time. and an electrophotographic photoreceptor.

In order to improve the durability of an electrophotographic photoreceptor (hereinafter simply referred to as "photoreceptor"), a technique of providing a protective layer on the surface of a photosensitive layer is known. In particular, a protective layer formed by polymerizing a photopolymerizable compound can form a protective layer having high surface strength because the photopolymerizable compound forms a three-dimensional structure through polymerization. Therefore, a photoreceptor having a protective layer with excellent durability can be obtained.
The photoreceptor includes a photoreceptor having a protective layer formed by forming a coating film as a protective layer using a coating liquid containing a polymerizable compound, followed by irradiation with infrared light and then irradiation with ultraviolet light. known (see, for example, Patent Document 1).
In addition, the photoreceptor has a protective layer formed by directly or indirectly contacting a heat medium to the inside of the conductive support to control the temperature of the conductive support during irradiation with LED light. A photoreceptor having a

However, in the technique disclosed in Patent Document 1, an ultraviolet lamp is used, and the light energy at the time of light irradiation deteriorates the polymerizable compound, which causes variations in electrical properties and wear properties. .
Further, in the technique disclosed in Patent Document 2, the uniformity of the surface temperature of the photoreceptor is insufficient, and a large difference occurs in the crosslink density inside the surface layer due to variations in the surface temperature of the substrate during light energy irradiation. It causes variations in wear characteristics and electrical characteristics.

JP 2016-200746 A JP 2011-118323 A

The present invention has been made in view of the above-mentioned problems and circumstances, and the problem to be solved is an electrophotography that has high abrasion resistance, good electrical characteristics, and can realize high image quality over a long period of time. An object of the present invention is to provide a method for manufacturing a photoreceptor and an electrophotographic photoreceptor.

In order to solve the above problems, the present inventors, in the process of studying the causes of the above problems, irradiate light energy using a light emitting diode as a light source under predetermined conditions to cure the coating film and form a protective layer. As a result, the surface condition of the protective layer is good, and by sufficiently hardening the inside of the protective layer, the hardening state is uniform, the wear resistance is high, the electrical properties are good, and high image quality can be achieved over a long period of time. The present inventors have found that a method for producing an electrophotographic photoreceptor and an electrophotographic photoreceptor can be provided.
That is, the above problems related to the present invention are solved by the following means.

1. A method for producing an electrophotographic photoreceptor having at least a photosensitive layer and a protective layer on a conductive support,
A step of forming a coating film as a protective layer using a coating liquid containing a polymerizable compound;
After forming the coating film, a step of curing the coating film by irradiation with light energy using a light emitting diode as a light source to form a protective layer,
A method for producing an electrophotographic photoreceptor, wherein the light energy satisfies the condition represented by the following formula (I).
Formula (I):
500 mW/cm ² <Peak irradiance on photoreceptor≦25000 mW/cm ²

2. 2. The method for producing an electrophotographic photoreceptor according to item 1, wherein the maximum emission wavelength of the light emitting diode is in the range of 360 to 405 nm.

3. 3. The method for producing an electrophotographic photoreceptor according to item 1 or item 2, wherein the light energy satisfies the condition represented by the following formula (II).
(Formula II):
1 J/cm ² ≦ Cumulative energy on photoreceptor ≦ 100 J/cm ²

4. A workpiece having a coated film of the photosensitive layer and the uncured protective layer formed on the vertically extending cylindrical conductive support surrounds the outer peripheral surface of the workpiece in the vertical transport path space. Items 1 to 3, wherein the protective layer is formed by curing the coating film by irradiating light energy from the light emitting diodes arranged in a ring shape along the circumferential direction. The method for producing an electrophotographic photoreceptor according to any one of the above.

［一般式（III）中、Ａｒ^１～Ａｒ^４は、それぞれ独立に、同一でも異なっていてもよく、それぞれ置換又は未置換のアリール基を表す。Ａｒ^５は、置換又は未置換のアリール基又はアリーレン基を表す。Ｄは、－（－（ＣＨ_２）ｄ－（Ｏ－（ＣＨ_２）ｆ－）ｅ－Ｏ－ＣＯ－Ｃ（Ｈ）＝ＣＨ_２）又は－（－（ＣＨ_２）ｄ－（Ｏ－（ＣＨ_２）ｆ－）ｅ－Ｏ－ＣＯ－Ｃ（ＣＨ_３）＝ＣＨ_２）を表す。ｃ１～ｃ５は、それぞれ独立に、０、１又は２を表す。ｋは０又は１を表す。ｄ及びｆは、それぞれ独立に、０以上５以下の整数を表す。ｅは、０又は１を表す。Ｄの総数（ｃ１＋ｃ２＋ｃ３＋ｃ４＋ｃ５）は、１以上である。］ 5. 5. Any one of items 1 to 4, wherein the protective layer of the electrophotographic photosensitive member contains a polymer of a hole-transporting compound having a structure represented by the following general formula (III): 1. The method for producing an electrophotographic photoreceptor according to claim 1.

[In general formula (III), Ar ¹ to Ar ⁴ may be the same or different, and each represents a substituted or unsubstituted aryl group. Ar ⁵ represents a substituted or unsubstituted aryl group or arylene group. D is -(-(CH ₂ )d-(O-(CH ₂ )f-)e-O-CO-C(H)=CH ₂ ) or -(-(CH ₂ )d-(O-( CH ₂ )f-) represents e—O—CO—C(CH ₃ )=CH ₂ ). c1 to c5 each independently represent 0, 1 or 2; k represents 0 or 1; d and f each independently represent an integer of 0 to 5; e represents 0 or 1; The total number of Ds (c1+c2+c3+c4+c5) is 1 or more. ]

6. 6. An electrophotographic photoreceptor manufactured by the method according to any one of items 1 to 5.

By means of the above means of the present invention, it is possible to provide a method for producing an electrophotographic photoreceptor and an electrophotographic photoreceptor that have high abrasion resistance, good electrical properties, and can achieve high image quality over a long period of time. can.
Although the expression mechanism or action mechanism of the effects of the present invention has not been clarified, it is speculated as follows.

When the illumination intensity irradiated to the coating film containing the polymerizable compound is low, the polymerization reaction proceeds gradually, so the degree of freedom of the polymerizable compound is hindered, the curing speed decreases, and the film is susceptible to oxygen inhibition. , the protective layer has a low cross-linking density.
Therefore, by irradiating the coating film containing the polymerizable compound with light energy for a short time at a peak irradiance of more than 500 mW/cm ² and 25000 mW/cm ² or less, The number of generated radicals increases, and the uniformity of the crosslink density on the surface and inside of the protective layer can be improved. As a result, in-plane density unevenness of the protective layer can be reduced, and a photoreceptor having excellent potential stability and abrasion resistance can be obtained. Moreover, the coating film can be easily cured without requiring a heating step.

Here, the LED light source used for irradiating light energy in the present invention will be described in detail.
In general, as a light source for irradiating light energy to generate radicals in a radically polymerizable compound, there are electrode lamps represented by high-pressure mercury lamps and metal halide lamps, and electrodeless lamps that excite light-emitting substances with microwave energy to emit light. there is a lamp As described above, the emission wavelength of these ultraviolet lamps is mainly 400 nm or less, but they also contain a lot of light with a wavelength of 400 nm or more, and even with light of a wavelength of 400 nm or less, the initiator has a wavelength at which radicals are generated. Light outside the domain is also included. In other words, the absorption of light in these unnecessary wavelength regions causes the temperature of the substrate, which is the object to be irradiated, to rise, causing surface irregularities during curing, and the rapid cross-linking reaction to increase the internal stress of the protective layer. It becomes the cause of film peeling of the layer.
Further, when the radically polymerizable compound having a charge-transporting structure as in the present invention is contained as the radically polymerizable compound, light of a specific wavelength from an ultraviolet lamp decomposes the radically polymerizable compound having a charge-transporting structure. be the cause.

Therefore, it is conceivable to use an infrared cut filter or an ultraviolet cut filter that cuts the unnecessary wavelength light of the ultraviolet lamp, but it is very difficult to efficiently transmit only the necessary wavelength light with a single filter. is difficult to In addition, a filter that absorbs long-wavelength light, such as an infrared cut filter, is used to cut light with a wavelength exceeding 400 nm.

From the above, the LED light source used in the present invention can emit only light in the wavelength range necessary for the initiator to generate radicals. The light source can be a light source that does not contain ultraviolet rays that decompose the radically polymerizable compound having a transport structure. In addition, LED light sources are very small and are not restricted to installation locations. In addition, while a general ultraviolet lamp is driven by an AC power supply and emits light periodically, an LED light source is driven by a DC power supply and emits light continuously, so the surface and inside of the film in the protective layer are hardened. There is an advantage that the uniformity of cross-linking is improved and the so-called cross-linking uniformity is improved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory partial cross-sectional view showing the configuration of an example of a light irradiation device according to the present invention; The bottom view of the light irradiation apparatus shown in FIG. Sectional view for explaining the light irradiation process using the light irradiation device shown in FIG. FIG. 3 is an external perspective view showing the configuration of another example of the light irradiation device according to the present invention; A cross-sectional view showing an example of the layer structure of the electrophotographic photoreceptor of the present invention. Diagram for explaining how to calculate the elastic deformation rate

The method for producing an electrophotographic photoreceptor of the present invention is a method for producing an electrophotographic photoreceptor having at least a photosensitive layer and a protective layer on a conductive support, wherein a coating liquid containing a polymerizable compound is used. forming a coating film as a protective layer; and, after forming the coating film, curing the coating film by irradiation with light energy using a light emitting diode as a light source to form a protective layer, The optical energy is characterized by satisfying the condition represented by the following formula (I).
Formula (I):
500 mW/cm ² <Peak irradiance on photoreceptor≦25000 mW/cm ²
This feature is a technical feature common to or corresponding to each of the following embodiments.

As an embodiment of the present invention, the maximum emission wavelength of the light-emitting diode is in the range of 360 to 405 nm, and the polymerizable compound contained in the coating film for forming the protective film does not generate radicals. This is preferable in that it is possible to irradiate only light in the wavelength region necessary for generation.

It is preferable that the light energy satisfies the condition represented by the formula (II) (1 J/cm ² ≤ accumulated energy on the photoreceptor ≤ 100 J/cm ² ) from the viewpoint of abrasion resistance and electrical properties. That is, when the accumulated energy is 1 J/cm ² or more, the degree of polymerization of the polymerizable compound contained in the coating film is sufficient, the abrasion resistance is excellent, and when the accumulated energy is 100 J/cm ² or less, It is possible to prevent uneven wear and deterioration of electrical characteristics due to deterioration of the resin.

A workpiece (object to be processed) having a coating film of the photosensitive layer and the uncured protective layer formed on the cylindrical conductive support extending in the vertical direction is placed in the vertical transport path space. Light energy is irradiated from the light emitting diodes arranged in a ring shape along the circumferential direction so as to surround the outer peripheral surface of the coating film, and the coating film is cured to form a protective layer. is preferred.

When the protective layer of the electrophotographic photosensitive member contains a polymer of a hole-transporting compound having a structure represented by the general formula (III), the charge mobility is excellent and the wear resistance is excellent. preferable.

The electrophotographic photoreceptor of the present invention is preferably produced by the production method described above.

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention, its constituent elements, and modes and modes for carrying out the present invention will be described below. In the present application, "-" is used to mean that the numerical values before and after it are included as the lower limit and the upper limit.

[Method for producing electrophotographic photoreceptor of the present invention]
The method for producing an electrophotographic photoreceptor of the present invention is a method for producing an electrophotographic photoreceptor having at least a photosensitive layer and a protective layer on a conductive support, wherein a coating liquid containing a polymerizable compound is used. forming a coating film as a protective layer; and, after forming the coating film, curing the coating film by irradiation with light energy using a light emitting diode as a light source to form a protective layer, The optical energy is characterized by satisfying the condition represented by the following formula (I).
Formula (I):
500 mW/cm ² <Peak irradiance on photoreceptor≦25000 mW/cm ²

<Peak irradiance>
In the present invention, the "peak irradiance" means that the light emitted from the light source is diffused and irradiated onto the photoreceptor surface in a Gaussian distribution, and the maximum irradiance in this Gaussian distribution is say. That is, it means the measured value at the portion where the illuminance of the light emitted from the light-emitting diode to the surface of the photoreceptor shows the maximum value.

For example, as will be described later, when a light source is arranged in a ring along the circumferential direction so as to surround the outer peripheral surface of a cylindrical workpiece that extends in the vertical direction, the light receiver is arranged in the vertical direction (vertical direction) of the workpiece. By scanning , the maximum value (peak value) of irradiance can be obtained. On the other hand, when a vertical light source arranged along the longitudinal direction (longitudinal direction) of the work is used, the maximum value (peak value) of the irradiance is similarly obtained by scanning the light receiver in the rotation direction of the work. is obtained.
In addition, the peak irradiance was measured using an integrated UV light meter “UIT-250” and a separate photodetector “UVD-S365” manufactured by Ushio Inc., and received light so that the irradiation distance was the same as that of the photoreceptor surface. It was measured by setting the instrument.

The peak irradiance is greater than 500 mW/cm ² and less than or equal to 25000 mW/cm ² . If it is less than 500 mW/cm ² , the cross-linking density is not sufficiently formed, resulting in uneven wear. On the other hand, when it is larger than 25000 mW/cm ² , uneven wear and electrical characteristics deteriorate due to deterioration of the resin. In particular, from the viewpoint of uneven wear and electrical properties, the peak irradiance is more preferably within the range of 1000 to 24000 mW/cm ² .

The peak irradiance can be controlled by adjusting the power (%) of the light source.

The maximum emission maximum wavelength of the light-emitting diode is in the range of 360 to 405 nm, the wavelength region necessary for generating radicals in the polymerizable compound contained in the coating film for forming the protective film. is preferable in that only the light of .
In the present invention, the term "maximum emission maximum wavelength" refers to the wavelength (nm) at which the emission spectrum exhibits the maximum and maximum emission intensity in the emission spectrum obtained by measuring the emission spectrum of a light emitting diode.

Moreover, it is preferable that the light energy satisfies the condition represented by the following formula (II) from the viewpoint of wear resistance and electrical properties. That is, when the accumulated energy is 1 J/cm ² or more, the degree of polymerization of the polymerizable compound contained in the coating film is sufficient, the abrasion resistance is excellent, and when the accumulated energy is 100 J/cm ² or less, It is possible to prevent uneven wear and deterioration of electrical characteristics due to deterioration of the resin.
Formula (II):
1 J/cm ² ≦ Cumulative energy on photoreceptor ≦ 100 J/cm ²
The integrated energy is a value obtained by multiplying the peak irradiance by the radiation time.
In addition, the integrated energy is measured using a UV integrated light meter "UIT-250" manufactured by Ushio Inc. and a separate type photodetector "UVD-S365". By doing so, the irradiance can be measured and calculated from the irradiance and the irradiation time.

The integrated energy can be controlled by adjusting the irradiance and irradiation time. Specifically, when the light irradiation device is the ring type described above, the workpiece pulling speed (mm/sec) is controlled, and when the light irradiation device is the vertical type (line shape) described above, the workpiece It is preferable to control the rotational speed (rpm) of the.

[Light irradiation device]
Two types, a ring type and a vertical type, of the light irradiation device used in the method of manufacturing the photoreceptor of the present invention will be described.
(1) First embodiment (ring type)
FIG. 1 is a partial cross-sectional view for explaining the configuration of an example of a light irradiation device, and FIG. 2 is a bottom view of the light irradiation device shown in FIG.
A light irradiation device is a device used to irradiate an uncured film formed on a photosensitive layer on a support with light to form a protective layer made of a cured resin.
Specifically, the light irradiation device 100 includes a substantially cylindrical machine frame 30 having a workpiece transfer path space S inside. In the work transport path space S, a vertically extending columnar work W is transported upward.
The machine frame 30 includes a lower machine frame 31 made of a cylindrical body having a double-tube structure, and a substantially cylindrical upper machine frame 32 provided on the upper surface of the lower machine frame 31 .
The upper machine frame 32 is composed of a ring-shaped triangular prism 16 and a ring-shaped fixing member 19 for fixing the triangular prism 16 . The triangular prism 16 has a vertically extending inner peripheral surface, a bottom surface continuously extending radially outward from the lower edge of the inner peripheral surface, and a tapered outer peripheral surface. A fixing member 19 is placed on the tapered outer peripheral surface, and the triangular prism 16 is fixed to the lower machine frame 31 .
A light exit window 15 through which light is actually emitted is formed on the inner peripheral surface of the triangular prism 16 corresponding to the work transport path space S. As shown in FIG.
Furthermore, a gas discharge port 25 is opened in the upper portion of the inner peripheral wall of the lower machine frame 31 .

Moreover, it is preferable that the distance (L1) between the gas discharge port 25 and the lowest end of the machine frame 30 is longer than the distance (L2) between the gas discharge port 25 and the uppermost end of the machine frame 30 .
With such a configuration, the nitrogen gas can be reliably flowed upward, and the nitrogen gas can be reliably supplied to the portion of the workpiece W to be irradiated with light. The reason why the nitrogen gas flows upward is that the longer the distance from the gas discharge port 25 to the outlet of the machine frame 30, the higher the pressure, and as a result, the nitrogen gas flows in the direction in which the distance to the outlet is short. be done.

Also, the distance (L1) between the gas discharge port 25 of the machine frame 30 and the bottom end of the machine frame 30 should be made longer than the distance (L2) between the gas discharge port 25 and the top end of the machine frame 30. For the purpose of obtaining the above, it is preferable to provide a cylindrical leg surrounding the workpiece transfer path space S in a state continuous with the machine frame 30 at the lower part of the machine frame 30 .
Furthermore, in the case where the machine frame 30 or a leg provided continuously therewith is configured to extend below the lowermost end of the work transfer path space S, the opening of the bottom is required for the purpose of ensuring the upward flow of nitrogen gas. It is preferable to provide a lid member that closes the .

<Nitrogen gas discharge means>
The gas discharge port 25 is an annular slit formed along the entire circumference of the inner peripheral wall of the lower machine frame 31 .
Since the gas discharge port 25 is an annular slit, nitrogen gas can be uniformly supplied to the portion of the uncured film that is irradiated with light, and as a result, a protective layer with suppressed uneven curing can be formed. can be done.

An internal space partitioned by the inner peripheral wall of the lower machine frame 31 and the partition wall forms a gas ascending passage 21 that extends vertically and whose upper portion communicates with the gas discharge port 25 .
The cross-sectional area of the gas ascending channel 21 is preferably within the range of 2 to 20 cm ² , for example.

In this light irradiation device 100, a columnar gas introduction channel member 23 having a gas introduction channel formed therein continues to the lower part of the partition wall of the lower machine frame 31 and accommodates a light guide member 12, which will be described later. It extends radially outward through the space 13 . A gas introduction port 28 is formed in the lower wall of the outer end portion (the right end portion in FIG. 1) of the gas introduction channel member 23 . One end (the left end in FIG. 1) of the gas introduction channel member 23 communicates with the gas ascending channel 21, and the gas introduction port 28 at the other end (the right end in FIG. 1) is shown in the figure. not connected to a nitrogen gas supply.

The gas discharge port 25, the gas ascending channel 21, the gas introduction channel (gas introduction channel member 23), and the nitrogen gas supply source constitute a nitrogen gas discharge means. Nitrogen gas from a supply source is introduced into the gas introduction channel in the gas introduction channel member 23 through the gas introduction port 28 and moves in the gas introduction channel in the left-right direction, and the gas in the lower machine frame 31 The gas is introduced into the ascending flow path 21 , moves vertically in the gas ascending flow path 21 , and is finally discharged from the gas discharge port 25 .

<Light irradiation means>
The light irradiation device 100 is provided with a light source 11 outside the machine frame 30 . A light guide member 12 for guiding the light from the light source 11 to the bottom surface of the triangular prism 16 is housed in the housing space 13 defined by the dividing wall of the lower frame 31 and the outer peripheral wall.

The light guide member 12 consists of a plurality of optical fibers. Specifically, one end close to the triangular prism 16 extends vertically and has a cylindrical shape as a whole. That is, the optical fibers are fixed so that the side faces are in contact with each other so that one end face is circular as a whole, and the respective optical fibers are bent independently of each other at the intermediate part, and at the other end side. It extends in the left-right direction and is formed in a bundled state.

An annular light inlet 13A is opened in a region defined by the partition wall and the outer peripheral wall on the upper wall of the lower machine frame 31 . Further, an insertion hole 13B through which the light guide member 12 is inserted is opened in the lower part of the outer peripheral wall of the lower machine frame 31 . The optical guide member 12 has one end surface of each optical fiber in contact with the bottom surface of the triangular prism 16 through the light introduction port 13A, and extends outside the lower frame 31 through the insertion hole 13B. is arranged to be connected to the light source 11 .

One end surface of the light guide member 12 that is in contact with the bottom surface of the triangular prism 16, that is, the light exit surface is formed in an annular shape as a whole. , is formed over the entire circumference. Therefore, it is possible to uniformly irradiate light in the circumferential direction of the cured film, and as a result, it is possible to form a protective layer in which uneven curing is suppressed.

As the optical fiber constituting the light guide member 12, it is preferable to use one made of quartz glass, multi-component glass, or the like.

As the light source 11, a light-emitting diode is used, which can emit light only in a wavelength region necessary for the polymerization initiator to generate radicals.
Further, it is preferable that the maximum emission wavelength of the light emitting diode used as the light source 11 is within the range of 360 to 405 nm. That is, it is particularly preferable to use an ultraviolet light emitting diode (UV-LED) as the light source 11 .

The triangular prism 16, the light guide member 12 and the light source 11 constitute light irradiation means. In the light irradiation means, the light emitted from the light source 11 is guided to the bottom surface of the triangular prism 16 by each optical fiber of the light guide member 12, and the light incident on the bottom surface of the triangular prism 16 is transmitted to the triangular prism 16 , and emitted from the inner peripheral surface of the triangular prism 16 (the light exit window 15). Therefore, the light emitted from the light emission window 15 is irradiated in a ring shape along the circumferential direction so as to surround the outer peripheral surface of the work W. As shown in FIG.
Therefore, such a light irradiation device 100 is also called a ring-type light irradiation device because it irradiates light in a ring shape.

Specifically showing an example of the dimensions of the light irradiation device 100 according to the present invention, the inner diameter of the lower machine frame 31 of the machine frame 30 is 40 mm, the outer diameter of the lower machine frame 31 is 100 mm, the inner diameter of the partition wall is 46 mm, and the lower The vertical length of the machine frame 31 is 870 mm, the vertical length of the upper machine frame 32 is 8 mm, the vertical size t1 of the gas discharge port 25 is 3 mm, and the vertical size t2 of the light exit window 15. is 7 mm, the distance (L1) between the gas discharge port 25 and the bottom end of the machine frame 30 is 855 mm, the distance (L2) between the gas discharge port 25 and the top end of the machine frame 30 is 12 mm, and the gas ascending flow path 21 is cut off. The area is 7.82 cm ² , the inner diameter of the triangular prism 16 is 40 mm, the number of optical fibers forming the light guide member 12 is 4000, and the diameter φ of the optical fibers is 0.2 mm. These dimensions are examples, and the present invention is not limited to these.

According to the light irradiation device 100 as described above, the gas ejection port 25 for ejecting nitrogen gas is provided at a lower level position than the light emission window 15 through which the light for curing the uncured film is emitted. Since the nitrogen gas discharged from the gas discharge port flows upward, the nitrogen gas can be supplied to the portion of the uncured film that is irradiated with light. Therefore, the area around the portion of the uncured film that is irradiated with light can be replaced with a nitrogen gas atmosphere, and as a result, the uncured film is sufficiently cured, thus forming a highly durable protective layer. can do.
In addition, since nitrogen gas is selectively supplied to the portion of the uncured film that is irradiated with light, the amount of nitrogen gas required for curing the uncured film is replaced with nitrogen gas in the closed system. Therefore, a high degree of design freedom is obtained, and the light irradiation device can be designed as a small one.
Furthermore, according to the light irradiation device 100, even when the workpiece transfer path space S is set to the air atmosphere, the nitrogen gas can be supplied to the portion of the uncured film that is irradiated with the light. With this configuration, a plurality of works W can be processed continuously.

The light irradiation device 100 described above is not limited to the above example, and various modifications can be made.

For example, the light irradiating means is not limited to a configuration including the triangular prism 16, and a plurality of optical fibers are arranged so that their light output surfaces face the work transport path space S, that is, the optical fibers are arranged from one end side to the other end side. A configuration having the light guide member 12 arranged in a state of extending in the horizontal direction to the side may be employed. In such a light guide member 12, the plurality of optical fibers may be arranged so that their light output surfaces are continuous, or may be arranged with even intervals.

Furthermore, the light irradiation means is not limited to the configuration in which the light source 11 is arranged outside the machine frame 30 , and may be arranged inside the machine frame 30 . Specifically, a plurality of LED light source chips are provided in the light exit window 15 without using an optical fiber, and the light exit surface of each LED light source chip is arranged to face the transport path space S. is preferred.

Further, for example, the optical guide member 12 is not limited to a state in which a plurality of optical fibers are in contact with each other at one end close to the triangular prism 16 so as to form a cylindrical shape as a whole. It is also possible to adopt a configuration of multi-point spots formed in a state in which they are arranged at equal intervals in the circumferential direction on the annular bottom surface of the triangular prism 16 .
With such a configuration of multiple spots, it is possible to obtain the same effect as the configuration in which the side surfaces are in contact with each other so as to form a cylindrical shape as a whole on one end side of the light guide member 12 .

Further, the configuration in which the light exit window 15 and the gas discharge port 25 are provided in the common machine frame 30 is not limited, and a configuration in which these are provided separately may be employed.

Further, for example, the structure is not limited to the configuration in which one gas discharge port is opened by an annular slit in the inner peripheral wall, and a plurality of gas discharge ports may be provided as long as they are provided so as to surround the work transfer path space S. It is also possible to adopt a configuration in which the gas discharge ports are opened at equal intervals in the circumferential direction.
The number of gas outlets is, for example, 4 to 40, preferably 20.
As for the size of each gas discharge port, it is preferable that the area thereof is within the range of 0.15 to 7 mm ² .
Such a configuration in which a plurality of gas ejection ports are opened can also provide the same effect as a configuration in which one gas ejection port is opened by an annular slit.

The ring-type light irradiation device 100 of the first embodiment is preferable in that it can suppress curing unevenness compared to the vertical light irradiation device 300 of the second embodiment described later. The reason for this is that, in the case of a ring-shaped light irradiation device, when the work is transported vertically, the photoreceptor is transported from weak light to strong light due to the distribution of light. On the other hand, in the vertical type light irradiation device, since the work is rotated while irradiating in a line, strong light is irradiated after a portion of weak irradiation is rotated halfway. As described above, due to the difference in the irradiation sequence, it is preferable to use a ring-type light irradiation device from the viewpoint of suppressing uneven curing.

(2) Second embodiment (vertical type)
FIG. 4 is a perspective view showing the configuration of an example of the light irradiation device.
Unlike the light irradiation device 100 of the first embodiment, the light irradiation device 300 according to the second embodiment emits light from a light source 302 along the vertical direction (vertical direction or longitudinal direction) of the cylindrical workpiece W. Diodes (LEDs) are arranged in a line in the vertical direction. Therefore, such a light irradiation device 300 is also called a vertical light irradiation device because it irradiates the work W with light along the vertical direction.
The light-emitting diode preferably has a maximum emission wavelength in the range of 360 to 405 nm, and more specifically, it is preferably a UV-LED.
In this light irradiation device 300, the workpiece W is rotated about its long axis, and the workpiece W is irradiated with light from the linear light-emitting diodes.
The light irradiation device 300 includes a vacuum chamber 301 and a light source 302 arranged inside the vacuum chamber 301 . The vacuum chamber 301 is provided with a pressure reduction port 301a for reducing the pressure in the vacuum chamber 301 by a vacuum pump (not shown) and a gas injection port 301b for injecting nitrogen gas, which is an inert gas.

An electrophotographic photoreceptor obtained by the method for producing an electrophotographic photoreceptor of the present invention has a photosensitive layer and a protective layer provided on the surface of the photosensitive layer (hereinafter also referred to as "surface protective layer").
It is preferable that the protective layer contains a polymer of a hole-transporting compound having a structure represented by general formula (III), which will be described later, from the viewpoint of excellent charge mobility and abrasion resistance.

[In general formula (III), Ar ¹ to Ar ⁴ may be the same or different, and each represents a substituted or unsubstituted aryl group. Ar ⁵ represents a substituted or unsubstituted aryl group or arylene group. D is -(-(CH ₂ )d-(O-(CH ₂ )f-)e-O-CO-C(H)=CH ₂ ) or -(-(CH ₂ )d-(O-( CH ₂ )f-) represents e—O—CO—C(CH ₃ )=CH ₂ ). c1 to c5 each independently represent 0, 1 or 2; k represents 0 or 1; d and f each independently represent an integer of 0 to 5; e represents 0 or 1; The total number of Ds (c1+c2+c3+c4+c5) is 1 or more. ]

Further, the photoreceptor has a photosensitive layer. The photosensitive layer has both the function of absorbing light to generate charges and the function of transporting charges.

The layer structure of the photosensitive layer may be a single-layer structure containing a charge-generating substance and a charge-transporting substance as long as there is a protective layer as the outermost layer. A laminate structure with a charge transport layer containing a substance may be used. Further, an intermediate layer may be provided between the conductive support and the photosensitive layer, if necessary. The layer structure of the photosensitive layer is not particularly limited, and specific layer structures including a protective layer and an intermediate layer are shown below, for example.

(i) A layer structure in which a photosensitive layer comprising a charge generation layer and a charge transport layer and a protective layer are sequentially laminated on a conductive support (ii) A charge transport substance and a charge generation substance are laminated on a conductive support Layer structure in which a single-layer photosensitive layer and a protective layer containing is laminated in order (iii) An intermediate layer, a photosensitive layer consisting of a charge generation layer and a charge transport layer, and a protective layer are laminated in order on a conductive support (iv) A layer structure in which an intermediate layer, a single-layer photosensitive layer containing a charge-transporting substance and a charge-generating substance, and a protective layer are sequentially laminated on a conductive support.

The photoreceptor according to the present invention may have any of the layer structures of (i) to (iv) above, and among these, the layer structure of (iii) above is particularly preferred.

In the cases (iii) and (iv) above, the outermost layer is the protective layer.

FIG. 5 is a cross-sectional view showing an example of the layer structure of the photoreceptor according to the present invention.
As shown in FIG. 5, the photoreceptor 200 is constructed by sequentially laminating an intermediate layer 202 , a photoreceptive layer 203 and a protective layer 204 on a conductive support 201 .
The photosensitive layer 203 is composed of a charge generation layer 203a and a charge transport layer 203b. Moreover, the protective layer 204 preferably contains metal oxide particles PS.

The photoreceptor according to the present invention is an organic photoreceptor in which at least one of the charge generation function and the charge transport function, which are indispensable for the construction of the electrophotographic photoreceptor, is expressed by an organic compound. It means an electrophotographic photoreceptor, and includes a photoreceptor composed of a known organic charge-generating substance or organic charge-transporting substance, a photoreceptor having a charge-generating function and a charge-transporting function composed of a polymer complex, and the like.

The process for producing a photoreceptor having the layer structure of (iii) is specifically described below.
Step (1): A step of applying a coating solution for forming an intermediate layer to the outer peripheral surface of the conductive support and drying to form an intermediate layer. Step (2): An intermediate layer formed on the conductive support. A step of forming a charge generation layer by applying a coating liquid for forming a charge generation layer to the outer peripheral surface of the layer and drying it Step (3): A charge transport layer is formed on the outer peripheral surface of the charge generation layer formed on the intermediate layer. A step of forming a charge transport layer by applying and drying a coating liquid for formation Step (4-1): Applying a coating liquid for forming a protective layer to the outer peripheral surface of the charge transport layer formed on the charge generation layer. An uncured film forming step of coating to form an uncured film to obtain a work W. Step (4-2): A light irradiation step of irradiating the uncured film of the work W with light to form a protective layer.

[Step (1): Intermediate layer forming step]
In this intermediate layer forming step (1), for example, a binder resin is dissolved in a known solvent to prepare an intermediate layer forming coating liquid, and this intermediate layer forming coating liquid is applied to the outer peripheral surface of the conductive support. In this step, a coating film is formed by drying the coating film, and an intermediate layer is formed by drying the coating film.

The intermediate layer formed in the intermediate layer forming step (1) provides a barrier function and an adhesive function between the conductive support and the photosensitive layer. It is preferable to provide such an intermediate layer from the viewpoint of preventing various failures.

(Conductive support)
The conductive support on which the intermediate layer is formed is not particularly limited as long as it has conductivity. Sheet-shaped products, metal foils such as aluminum and copper laminated on plastic films, plastic films vapor-deposited with aluminum, indium oxide, tin oxide, etc., and conductive substances applied alone or with a binder resin. Metal, plastic film or paper provided with a conductive layer may be used.

(binder resin)
Binder resins used in the intermediate layer forming step (1) include, for example, casein, polyvinyl alcohol, nitrocellulose, ethylene-acrylic acid copolymers, polyamide resins, polyurethane resins, and gelatin. Preferably.

(solvent)
The solvent used in the intermediate layer forming step (1) preferably disperses the inorganic fine particles described later and dissolves the binder resin. Specific examples include ethanol, n-propyl alcohol, isopropyl alcohol, Alcohols having 2 to 4 carbon atoms such as n-butanol, t-butanol and sec-butanol are particularly preferred from the viewpoint of the solubility and coatability of the polyamide resin.
In the intermediate layer forming step (1), it is preferable to use a co-solvent together with the solvent in order to improve storage stability and dispersibility of the inorganic fine particles. , toluene, methylene chloride, cyclohexanone, tetrahydrofuran, and the like.

(Inorganic fine particles)
The intermediate layer-forming coating liquid may contain inorganic fine particles such as various conductive fine particles and metal oxide fine particles for the purpose of adjusting the resistance of the intermediate layer to be formed.

Examples of the inorganic fine particles contained in the intermediate layer forming coating solution include metal oxide fine particles such as alumina, zinc oxide, titanium oxide, tin oxide, antimony oxide, indium oxide, and bismuth oxide. Ultrafine particles such as indium oxide, antimony-doped tin oxide and zirconium oxide can also be used. These metal oxide fine particles can be used alone or in combination of two or more. When two or more metal oxide fine particles are used in combination, even if the metal oxide fine particles are in a solid solution state, Alternatively, it may be in a fused state.

The number average primary particle size of such metal oxide fine particles is preferably 0.3 μm or less, more preferably 0.1 μm or less.
In the present invention, the number average primary particle size of the metal oxide fine particles is measured as follows.
That is, a 10,000-fold enlarged photograph was taken with a scanning electron microscope "JSM-7500F" (manufactured by JEOL Ltd.), and a photographic image (excluding aggregated particles) of 300 metal oxide fine particles randomly captured by a scanner was obtained. It is calculated using an automatic image processing analyzer "LUZEX AP" (software version Ver. 1.32, manufactured by Nireco Corporation).

The means for dispersing the inorganic fine particles in the coating solution for forming the intermediate layer is not particularly limited, but examples thereof include dispersing machines such as ultrasonic dispersers, ball mills, sand grinders and homomixers.

The amount of inorganic fine particles added is preferably in the range of 20 to 400 parts by mass, more preferably in the range of 50 to 200 parts by mass, per 100 parts by mass of the binder resin.

The coating method of the intermediate layer forming coating liquid is not particularly limited, but includes, for example, a dip coating method and a spray coating method.

A method for drying the coating film of the intermediate layer-forming coating liquid can be appropriately selected according to the type of solvent and the layer thickness of the intermediate layer to be formed, but a method using heat drying is preferable.

The layer thickness of the intermediate layer formed in the intermediate layer forming step (1) is preferably in the range of 0.1 to 15 μm, more preferably in the range of 0.3 to 10 μm.

[Step (2): Charge generating layer forming step]
In the charge-generating layer forming step (2), for example, a charge-generating substance is added to and dispersed in a binder resin dissolved in a known solvent to prepare a charge-generating layer-forming coating liquid. In this step, a coating liquid is applied to the outer peripheral surface of the intermediate layer formed in the intermediate layer forming step (1) to form a coating film, and the coating film is dried to form a charge generating layer.

(binder resin)
As the binder resin used in the charge generating layer forming step (2), known resins can be used. Examples include polystyrene resin, polyethylene resin, polypropylene resin, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, polyvinyl butyral resins, epoxy resins, polyurethane resins, phenolic resins, polyester resins, alkyd resins, polycarbonate resins, silicone resins, melamine resins, and copolymer resins containing two or more of these resins (e.g., vinyl chloride-acetic acid vinyl copolymer resins, vinyl chloride-vinyl acetate-maleic anhydride copolymer resins), poly-vinylcarbazole resins, etc., but are not limited thereto.

(solvent)
Examples of solvents used in the charge generation layer forming step (2) include toluene, xylene, methylene chloride, 1,2-dichloroethane, methyl ethyl ketone, cyclohexane, ethyl acetate, butyl acetate, methanol, ethanol, propanol, butanol, and methyl cellosolve. , ethyl cellosolve, tetrahydrofuran, 1-dioxane, 1,3-dioxolane, pyridine, diethylamine, and the like, but are not limited thereto.

(Charge-generating substance)
The charge-generating substance used in the charge-generating layer forming step (2) is not particularly limited, but examples include azo raw materials such as Sudan Red and Diane Blue; quinone pigments such as pyrenequinone and anthanthrone; quinocyanine pigments; perylene pigments; indigo pigments such as indigo and thioindigo; and phthalocyanine pigments. These charge-generating substances can be used alone or in combination of two or more.

The amount of the charge-generating substance added is preferably in the range of 1 to 600 parts by mass, more preferably in the range of 50 to 500 parts by mass, per 100 parts by mass of the binder resin.

The means for dispersing the charge-generating substance is not particularly limited, but examples thereof include dispersers such as ultrasonic dispersers, ball mills, sand grinders and homomixers.

The method of applying the charge generation layer forming coating liquid is not particularly limited, but examples thereof include dip coating and spray coating.

A method for drying the coating film of the coating liquid for forming the charge generation layer can be appropriately selected depending on the type of solvent and the thickness of the charge generation layer to be formed, but a method by heat drying is preferable.

The layer thickness of the charge generation layer formed in the charge generation layer forming step (2) varies depending on the properties of the charge generation material, the properties of the binder resin, the mixing ratio, etc., but is preferably in the range of 0.01 to 5 μm. Preferably, it is in the range of 0.05 to 3 μm. It should be noted that the generation of image defects can be prevented by filtering foreign substances and aggregates before applying the coating liquid for forming the charge generation layer. It can also be formed by vacuum deposition of the pigment.

[Step (3): Charge transport layer forming step]
In this step (3), for example, a charge-transporting material (CTM) is added to a binder resin dissolved in a known solvent to prepare a charge-generating layer-forming coating liquid, and the charge-generating layer-forming coating liquid is prepared. In this step, a coating film is formed by coating the outer peripheral surface of the charge generating layer formed in step (2), and the coating film is dried to form the charge transport layer.

(binder resin)
As the binder resin used in step (3), known resins can be used, such as polycarbonate resin, polyacrylate resin, polyester resin, polystyrene resin, styrene-acrylonitrile copolymer resin, polymethacrylic acid ester resin, styrene -Methacrylic acid ester copolymer resins and the like can be mentioned, but polycarbonate resins are preferred. Further, bisphenol A (BPA), bisphenol Z (BPZ), dimethyl BPA, BPA-dimethyl BPA copolymer, etc. are preferable in terms of crack resistance, wear resistance and charging characteristics.

(solvent)
Examples of solvents used in step (3) include toluene, xylene, methylene chloride, 1,2-dichloroethane, methyl ethyl ketone, cyclohexanone, ethyl acetate, butyl acetate, methanol, ethanol, propanol, butanol, tetrahydrofuran, 1,4- Examples include, but are not limited to, dioxane, 1,3-dioxolane, pyridine, diethylamine, and the like.

(Charge transport substance)
Examples of charge-transporting substances used in step (3) include carbazole derivatives, oxazole derivatives, oxadiazole derivatives, thiazole derivatives, thiadiazole derivatives, triazole derivatives, imidazole derivatives, imidazolone derivatives, imidazolidine derivatives, bisimidazolidine derivatives, Styryl compounds, hydrazone compounds, pyrazoline compounds, oxazolone derivatives, benzimidazole derivatives, quinazoline derivatives, benzofuran derivatives, acridine derivatives, phenazine derivatives, aminostilbene derivatives, triarylamine derivatives, phenylenediamine derivatives, stilbene derivatives, benzidine derivatives, poly-N -vinylcarbazole, poly-1-vinylpyrene and poly-9-vinylanthracene, triphenylamine derivatives and the like. These charge transport substances can be used alone or in combination of two or more.

The amount of the charge-transporting substance added is preferably in the range of 10 to 500 parts by mass, more preferably in the range of 20 to 100 parts by mass, per 100 parts by mass of the binder resin.

The coating solution for forming the charge transport layer may contain an antioxidant, an electron conductive agent, a stabilizer, and the like, if necessary. Antioxidants include those described in Japanese Patent Application No. 11-200135, and electronic conductive agents include those described in JP-A-50-137543 and JP-A-58-76483.

The method of applying the coating liquid for forming the charge transport layer is not particularly limited, but includes, for example, a dip coating method and a spray coating method.

The method for drying the coating film of the coating liquid for forming the charge transport layer can be appropriately selected according to the type of solvent and the layer thickness of the charge transport layer to be formed, but a method using heat drying is preferred.

The layer thickness of the charge transport layer formed in step (3) varies depending on the properties of the charge transport material, the properties of the binder resin, the mixing ratio, etc., but is preferably in the range of 5 to 40 μm, more preferably 10 μm. It is in the range of ~30 μm.

[Step (4-1): Uncured film forming step]
This step (4-1) includes a polymerizable compound forming a cured resin constituting a protective layer, a photopolymerization initiator, and optionally metal oxide fine particles, lubricant particles, an antioxidant, or a resin other than the cured resin. is added to a known solvent to prepare a protective layer-forming coating solution, and this protective layer-forming coating solution is applied to the outer peripheral surface of the charge transport layer formed in step (3) to form an uncured film. , and drying to obtain a workpiece W.

(Polymerizable compound)
As the polymerizable compound used in step (4), a polymerizable compound having at least two polymerizable groups in the molecule (also referred to as "polyfunctional polymerizable compound" or "polyfunctional polymerizable monomer") is preferable. .
The polyfunctional polymerizable compound includes a polyfunctional polymerizable compound having a hole-transporting property and a polyfunctional polymerizable compound having no hole-transporting property (having no hole-transporting property).

Here, the term "hole-transporting property" in the present invention means having a higher hole-transporting property than an electron-transporting property. That is, it refers to a characteristic in which the hole mobility is higher than the electron mobility.
An ionization potential (energy required to remove electrons from a molecule in a neutral state to ionize it) is preferably 6.2 eV or less in terms of easy hole injection, particularly 4.5 to 6.2 eV. Being within the range is also preferable from the viewpoint of preventing oxidation of the compound.
As the hole transport ability, those having a drift mobility of 1×10 ⁻⁷ cm ² /Vsec or more are preferable.

The method for measuring hole or electron mobility is not particularly limited. Specific methods include, for example, the following methods.
(a) Time of flight method (method of calculating from measurement of transit time of charge in organic film)
(b) Method of calculating from voltage characteristics of space charge limited current (c) Method of determining from peak frequency measured by impedance spectroscopy

Examples of the "polymerizable compound having a hole-transport property" include polycyclic aromatic compounds, heterocyclic compounds, hydrazone compounds, styryl compounds, enamine compounds, benzidine compounds, triarylamine compounds, and compounds derived from these substances. and a compound having a group. Among these, a triarylamine compound and a benzidine compound are preferable, and specifically the compounds described later.

Further, the "non-hole-transporting polymerizable compound" includes the above-described polycyclic aromatic compounds, heterocyclic compounds, hydrazone compounds, styryl compounds, enamine compounds, benzidine compounds, triarylamine compounds, and compounds from these substances. It is a polymerizable compound other than a compound having an inducible group, specifically a compound described later.

Further, as the polymerizable compound forming the cured resin constituting the protective layer, in addition to the polyfunctional polymerizable compound, a polymerizable compound having one polymerizable group in the molecule ("monofunctional polymerizable compound" or " Also referred to as "monofunctional polymerizable monomer") is also preferably used. The monofunctional polymerizable compound preferably has hole-transport properties.
Therefore, the protective layer according to the present invention is a coating liquid containing the polyfunctional polymerizable compound having hole-transporting property and the polyfunctional polymerizable compound having no hole-transporting property (also referred to as "protective layer-forming coating liquid"). ) is preferably a cured product.
Furthermore, the coating liquid preferably contains a photopolymerization initiator and inorganic particles, and a monofunctional polymerizable compound having a hole-transporting property, and a polyfunctional or monofunctional polymerizable compound having a hole-transporting property. known charge transport materials.

Examples of the polyfunctional polymerizable compound having a hole-transporting property or not having a hole-transporting property include, for example, a photoreceptor binder resin that has a radically polymerizable functional group and is polymerized (cured) by a radical polymerization initiator. Constituent monomers are preferably used. Examples of binder resins include polystyrene and polyacrylate.
From the viewpoint of maintaining high durability, it is preferable to use a crosslinkable polymerizable compound as the polyfunctional polymerizable compound. Specific examples of crosslinkable polymerizable compounds include polymerizable compounds having two or more radically polymerizable functional groups.

Hereinafter, [1] a polyfunctional or monofunctional polymerizable compound having a hole-transporting property, [2] a polyfunctional polymerizable compound not having a hole-transporting property, [3] a photopolymerization initiator, [4] inorganic particles, and [5] Other additives and the like will be described in order.

[1] Polyfunctional or monofunctional polymerizable compound having hole-transporting property (hole-transporting compound having a structure represented by general formula (III))
The polyfunctional or monofunctional polymerizable compound having a hole-transporting property is preferably a hole-transporting compound having a structure represented by the following general formula (III), since it is particularly excellent in charge mobility and the like. preferable. That is, the protective layer according to the invention preferably contains a polymer of a hole-transporting compound having a structure represented by the following general formula (III).

［式一般式（III）中、Ａｒ^１～Ａｒ^４は、それぞれ独立に、同一でも異なっていてもよく、それぞれ置換又は未置換のアリール基を表す。Ａｒ^５は、置換又は未置換のアリール基又はアリーレン基を表す。Ｄは、－（－（ＣＨ_２）ｄ－（Ｏ－（ＣＨ_２）ｆ－）ｅ－Ｏ－ＣＯ－Ｃ（Ｈ）＝ＣＨ_２）又は－（－（ＣＨ_２）ｄ－（Ｏ－（ＣＨ_２）ｆ－）ｅ－Ｏ－ＣＯ－Ｃ（ＣＨ_３）＝ＣＨ_２）を表す。ｃ１～ｃ５は、それぞれ独立に、０、１又は２を表す。ｋは０又は１を表す。ｄ及びｆは、それぞれ独立に、０以上５以下の整数を表す。ｅは、０又は１を表す。Ｄの総数（ｃ１＋ｃ２＋ｃ３＋ｃ４＋ｃ５）は、１以上である。］

[In general formula (III), Ar ¹ to Ar ⁴ may be the same or different and each represents a substituted or unsubstituted aryl group. Ar ⁵ represents a substituted or unsubstituted aryl group or arylene group. D is -(-(CH ₂ )d-(O-(CH ₂ )f-)e-O-CO-C(H)=CH ₂ ) or -(-(CH ₂ )d-(O-( CH ₂ )f-) represents e—O—CO—C(CH ₃ )=CH ₂ ). c1 to c5 each independently represent 0, 1 or 2; k represents 0 or 1; d and f each independently represent an integer of 0 to 5; e represents 0 or 1; The total number of Ds (c1+c2+c3+c4+c5) is 1 or more. ]

In the general formula (III), d+f is preferably an integer of 1 or more, more preferably an integer of 3 to 5.

In general formula (III), Ar ¹ to Ar ⁴ are preferably any one of the following formulas (1) to (7). The following formulas (1) to (7) collectively represent “-(D) _C1 ” to “-(D) _C4 ” that can be linked to each of Ar ¹ to Ar ⁴ . _C ”.

In the above formulas (1) to (7), R ¹ is substituted with a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkyl group having 1 to 4 carbon atoms or an alkoxy group having 1 to 4 carbon atoms. represents one selected from the group consisting of a phenyl group, an unsubstituted phenyl group, and an aralkyl group having 7 to 10 carbon atoms;
R ² to R ⁴ are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, a phenyl group substituted with an alkoxy group having 1 to 4 carbon atoms, represents one selected from the group consisting of an unsubstituted phenyl group, an aralkyl group having 7 to 10 carbon atoms, and a halogen atom;
Ar represents a substituted or unsubstituted arylene group.
D is -(-(CH ₂ )d-(O-(CH ₂ )f-)e-O-CO-C(H)=CH ₂ ) or -(-(CH ₂ )d-(O-(CH ₂ ) f-) e—O—CO—C(CH ₃ )=CH ₂ )
represents
d and f are each independently an integer of 0 to 5; e represents 0 or 1, c represents 0, 1 or 2, s represents 0 or 1, and t represents an integer of 1 or more and 3 or less.

Here, Ar in formula (7) is preferably represented by the following formula (8) or (9).

In formulas (8) and (9), R ⁵ and R ⁶ each independently represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or 1 to 4 carbon atoms. represents one selected from the group consisting of a phenyl group substituted with an alkoxy group of , an unsubstituted phenyl group, an aralkyl group having from 7 to 10 carbon atoms, and a halogen atom. t represents an integer of 1 or more and 3 or less.

Z' in formula (7) is preferably represented by any one of formulas (10) to (17) below.

In formulas (10) to (17), R ⁷ and R ⁸ are each independently a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, an alkoxy group having 1 to 4 carbon atoms, or 1 to 4 carbon atoms. represents one selected from the group consisting of a phenyl group substituted with an alkoxy group of , an unsubstituted phenyl group, an aralkyl group having from 7 to 10 carbon atoms, and a halogen atom. W represents a divalent group, q and r each independently represent an integer of 1 or more and 10 or less, and t represents an integer of 1 or more and 3 or less.

W in the above formulas (16) to (17) is preferably any one of divalent groups represented by the following (18) to (26). However, in Formula (25), u represents an integer of 0 or more and 3 or less.

In general formula (III), Ar ⁵ is an aryl group (1) to (7) exemplified in the description of Ar ¹ to Ar ⁴ when k is 0, and when k is 1 It is an arylene group obtained by removing a predetermined hydrogen atom from the aryl group of (1) to (7).

Specific examples of the hole-transporting compound having the structure represented by formula (III) are shown below, but are not limited thereto. In addition, in the compounds shown below, R represents a methacryloyl group or an acryloyl group ((meth)acryloyl group).

Among the hole-transporting compounds having the structure represented by the general formula (III), compounds having one (meth)acryloyl group include, for example, the following compounds.

Among the hole-transporting compounds having the structure represented by general formula (III), examples of those having two (meth)acryloyl groups include the following compounds.

Among the hole-transporting compounds having the structure represented by general formula (III), examples of compounds having three (meth)acryloyl groups include the following compounds.

Among hole-transporting compounds having a structure represented by general formula (III), compounds having four or more (meth)acryloyl groups include, for example, the following compounds.

A hole-transporting compound having a structure represented by general formula (III) can be synthesized according to the synthesis route of compound 4-4a and compound 4-17a shown below.
Compound 4-4a is compound 4-4 in which R is an acryloyl group (CH ₂ ═CHCO—), and compound 4-17a is compound 4-17 in which R is an acryloyl group. .

(Synthetic route of compound 4-4a)

(Synthetic route of compound 4-17a)

[2] Non-hole-transporting polyfunctional polymerizable compound Specific examples of the non-hole-transporting polyfunctional polymerizable compound are shown below, but are not limited thereto.

In the chemical formulas representing the exemplary compounds M1 to M14 above, R represents an acryloyl group (CH ₂ =CHCO--) and R' represents a methacryloyl group (CH ₂ =CCH ₃ CO--).

[3] Photopolymerization initiator The photopolymerization initiator according to the present invention is not particularly limited. - A monomolecular photopolymerization initiator having an acyl oxime structure is preferred. These may be used individually by 1 type, and may use multiple types together. In the present invention, the term “unimolecular photopolymerization initiator” means that one molecule alone functions as a photopolymerization initiator, and the term “bimolecular photopolymerization initiator” means that two or more molecules are prepared for the first time. A substance that functions as a photopolymerization initiator.

Specific examples of photopolymerization initiators having an acylphosphine oxide structure are shown below.

Of the two, Irgacure TPO (manufactured by BASF Japan Ltd.) and Irgacure 819 (manufactured by BASF Japan Ltd.), Irgacure 819 is preferred.

Further, examples of the photopolymerization initiator having an O-acyloxime structure include Irgacure OXE02 (manufactured by BASF Japan) and the compounds shown below.

In the present invention, the photopolymerization initiator having an O-acyloxime structure is preferably a photopolymerization initiator having a structure represented by the following general formula (a-3).

In general formula (a-3), each of R ₁ and R ₂ is independently a hydrogen atom, an optionally substituted alkyl group having 1 to 6 carbon atoms, and an optionally substituted It represents a cycloalkyl group having 3 to 6 carbon atoms or an aryl group which may have a substituent.
R ₃ is a hydrogen atom, an optionally substituted alkyl group having 1 to 6 carbon atoms, an optionally substituted alkoxy group having 1 to 6 carbon atoms, or It represents a good aryl group, a halogen atom, a cyano group, a nitro group, a hydroxy group, or a carbonyl group which may have a substituent.
The alkyl group in general formula (a-3) includes, for example, a methyl group, an ethyl group,
Examples include propyl group, isopropyl group, (t) butyl group, pentyl group, hexyl group, octyl group, dodecyl group, tridecyl group, tetradecyl group, pentadecyl group and benzyl group. Examples of the cycloalkyl group in general formula (a-3) include cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group and the like. Examples of the aryl group in general formula (a-3) include a phenyl group, p-chlorophenyl group, mesityl group, tolyl group, xylyl group, naphthyl group, anthryl group, azulenyl group, acenaphthenyl group, fluorenyl group, and phenanthryl. group, indenyl group, pyrenyl group, biphenylyl group and the like. Examples of the alkoxy group in general formula (a-3) include methoxy group, ethoxy group, propyloxy group, butoxy group, pentyloxy group, hexyloxy group, octyloxy group and dodecyloxy group.
In addition, these substituents may be further substituted with the above substituents, or they may be condensed with each other to form a ring.

Specific examples of the compound having the structure represented by the general formula (a-3) are shown below.

Commercially available photopolymerization initiators having an O-acyloxime structure include, for example, Irgacure OXE01 (manufactured by BASF Japan Ltd.) of the above exemplary compound B-1, and O-acyloxy having a disulfide structure in the compound. PBG-305 and PBG-329 (both of which are manufactured by Changzhou Yuan Yuan Electronic New Materials Co., Ltd.), etc., are exemplified.

Further, the photopolymerization initiator according to the present invention is not limited to the above monomolecular photopolymerization initiator, and a bimolecular photopolymerization initiator can also be used. Examples of the bimolecular photopolymerization initiator include a combination of a compound having a hexaarylbisimidazole structure and a thiol compound.

Specific examples of compounds having a hexaarylbisimidazole structure that are used as bimolecular photopolymerization initiators are shown below.

Further, specific examples of the thiol compound used for the bimolecular photopolymerization initiator are shown below.

The addition ratio of the photopolymerization initiator is preferably in the range of 0.1 to 10% by volume with respect to 100% by volume of the solid content of the coating liquid for forming the protective layer, and 1 to 5% by volume, as described later. More preferably, it is within the volume percent range.

In addition to the photopolymerization initiators described above, other known photopolymerization initiators may be further contained.

[4] Inorganic Particles The protective layer according to the invention preferably contains inorganic particles, and more preferably contains metal oxide particles as the inorganic particles.
As the metal oxide particles, fine metal oxide particles including transition metals are preferable. For example, silica (silicon dioxide), magnesium oxide, zinc oxide, lead oxide, aluminum oxide, tantalum oxide, indium oxide, bismuth oxide, yttrium oxide, cobalt oxide, copper oxide, manganese oxide, selenium oxide, iron oxide, zirconium oxide, Metal oxide particles such as germanium oxide, tin oxide, titanium oxide, niobium oxide, molybdenum oxide and vanadium oxide are exemplified. Among them, tin oxide fine particles, titanium oxide fine particles, zinc oxide fine particles, and alumina fine particles are preferable because they can improve the abrasion resistance of the protective layer.

The above metal oxide particles are preferably produced by a known method such as a gas phase method, a chlorine method, a sulfuric acid method, a plasma method and an electrolysis method.

The number-average primary particle size of the metal oxide particles is, for example, preferably in the range of 1 to 300 nm, particularly preferably in the range of 3 to 100 nm.

The addition ratio of the metal oxide particles is preferably in the range of 0.1 to 30% by volume, preferably 1 to 20%, with respect to 100% by volume of the solid content of the coating liquid for forming the protective layer, as described later. More preferably, it is within the volume percent range.

[4.1] Method for measuring the particle size of metal oxide particles The particle size (number-average primary particle size) of the metal oxide particles is measured by taking a 10,000-fold enlarged photograph with a scanning electron microscope (manufactured by JEOL Ltd.). Then, photographic images (aggregated particles were excluded) of 300 particles picked up at random by a scanner were scanned with an automatic image processing analyzer "LUZEX (registered trademark) AP" (manufactured by Nireco Co., Ltd.) software Ver. 1.32 is used to perform binarization processing, calculate the Feret diameter in the horizontal direction, and calculate the average value as the number average primary particle diameter. Here, the horizontal Feret diameter refers to the length of the side parallel to the x-axis of the circumscribed rectangle obtained by binarizing the image of the metal oxide particles.

[4.2] Surface Modification In the present invention, the metal oxide particles preferably have a reactive organic group. That is, from the viewpoint of dispersibility and wear resistance of the photoreceptor, the surface is preferably modified with a surface modifier having a reactive organic group.

As the surface modifier, there may be used a surface modifier that reacts with hydroxy groups or the like present on the surface of the metal oxide particles before surface modification. Examples of such surface modifiers include silane coupling agents and titanium cups. ring agents and the like.
Further, in the present invention, in order to further increase the hardness of the protective layer, it is preferable to use a surface modifier having a reactive organic group, and it is more preferable to use one in which the reactive organic group is a radically polymerizable functional group. preferable. By using a surface modifier having a radically polymerizable functional group, a strong protective film can be formed because it also reacts with the radically polymerizable binder compound and the charge-transporting substance contained in the protective layer.
As the surface modifier having a radically polymerizable functional group, it is preferable to use a silane coupling agent having an acryloyl group or a methacryloyl group. known compounds are exemplified.

S-1: CH ₂ =CHSi(CH ₃ )(OCH ₃ ) ₂
S-2: CH ₂ =CHSi(OCH ₃ ) ₃
S-3: CH ₂ =CHSiCl ₃
S-4: _CH2 =CHCOO( _CH2 ) _2Si ( _CH3 )( _OCH3 ) ₂
S-5: _CH2 =CHCOO( _CH2 ) _2Si ( _OCH3 ) ₃
S-6: _CH2 =CHCOO( _CH2 ) _{2Si ( OC2H5} )( _OCH3 ) ₂
S-7: _CH2 =CHCOO( _CH2 ) _3Si ( _OCH3 ) ₃
S-8: _CH2 =CHCOO( _CH2 ) _2Si ( _CH3 ) _Cl2
S-9: _CH2 =CHCOO _{( CH2} ) _2SiCl3
S-10: _CH2 =CHCOO( _CH2 ) _3Si ( _CH3 ) _Cl2
S -11: _CH2 =CHCOO( _CH2 ) _3SiCl3
S-12: _CH2 =C( _CH3 )COO( _CH2 ) _2Si ( _CH3 )( _OCH3 ) ₂
S-13: _CH2 =C( _CH3 )COO( _CH2 ) _2Si ( _OCH3 ) ₃
S-14: _CH2 =C( _CH3 )COO( _CH2 ) _3Si ( _CH3 )( _OCH3 ) ₂
S-15: _CH2 =C( _CH3 )COO( _CH2 ) _3Si ( _OCH3 ) ₃
S-16: _CH2 =C( _CH3 )COO( _CH2 ) _2Si ( _CH3 ) _Cl2
S-17: _CH2 =C( _CH3 ) _COO ( _CH2 ) _2SiCl3
S-18: _CH2 =C( _CH3 )COO( _CH2 ) _3Si ( _CH3 ) _Cl2
S-19: _CH2 =C( _CH3 ) _COO ( _CH2 ) _3SiCl3
S-20 _{: CH2} =CHSi( _C2H5 )( _OCH3 ) ₂
S-21: CH ₂ =C(CH ₃ )Si(OCH ₃ ) ₃
S- ₂₂ : _CH2 =C( _CH3 )Si( _OC2H5 ) ₃
S-23: CH ₂ =CHSi(OCH ₃ ) ₃
S-24: CH ₂ =C(CH ₃ )Si(CH ₃ )(OCH ₃ ) ₂
S-25: _CH2 =CHSi( _CH3 ) _Cl2
S-26: _CH2 =CHCOOSi( _OCH3 ) ₃
S-27: _CH2 = _CHCOOSi ( _OC2H5 ) ₃
S-28: _CH2 =C( _CH3 )COOSi( _OCH3 ) ₃
S- ₂₉ : _CH2 =C( _CH3 )COOSi( _OC2H5 ) ₃
S- ₃₀ : _CH2 =C( _CH3 )COO( _CH2 ) _3Si ( _OC2H5 ) ₃
S-31: _CH2 =CHCOO( _CH2 ) _2Si ( _CH3 ) ₂ ( _OCH3 )
S-32: _CH2 =CHCOO( _CH2 ) _2Si ( _CH3 )( _OCOCH3 ) ₂
S-33: _CH2 =CHCOO( _CH2 ) _2Si ( _CH3 )( _ONHCH3 ) _2
S -34: _CH2 =CHCOO( _CH2 ) _2Si ( _CH3 )( _OC6H5 ) ₂
S- ₃₅ : _CH2 =CHCOO( _CH2 ) _2Si ( _C10H21 )( _OCH3 ) ₂
S-36 _{: CH2} =CHCOO _{( CH2} ) _2Si ( _CH2C6H5 )( _OCH3 ) ₂

As the surface modifier, in addition to the above S-1 to S-36, a silane compound having a reactive organic group capable of undergoing a radical polymerization reaction can be used. These surface modifiers can be used alone or in combination of two or more.

The amount of the surface modifier used is not particularly limited, but is preferably in the range of 0.1 to 100 parts by mass with respect to 100 parts by mass of the metal oxide particles before modification.

[4.3] Method for surface modification of metal oxide particles Specifically, the surface modification of metal oxide particles is performed by slurry (suspension of solid particles) containing metal oxide particles before modification and a surface modifier. By wet pulverizing the metal oxide particles, the surface modification of the particles is progressed at the same time as the metal oxide particles are refined, and then the solvent is removed and powdered.

The slurry is preferably prepared by mixing 0.1 to 100 parts by mass of the surface modifier and 50 to 5000 parts by mass of the solvent with respect to 100 parts by mass of the metal oxide particles before modification.

Moreover, as an apparatus used for wet pulverization of the slurry, a wet media dispersion type apparatus can be mentioned.
A wet media dispersion type device is a container filled with beads as media, and agglomerated particles of metal oxide particles are crushed, pulverized, and dispersed by rotating a stirring disk attached perpendicularly to the rotating shaft at high speed. It is an apparatus having a process, and there is no problem as long as the structure is a form that allows the metal oxide particles to be sufficiently dispersed and the surface can be modified when the metal oxide particles are surface-modified. , continuous type, batch type, etc., can be used. Specifically, sand mills, ultravisco mills, pearl mills, grain mills, dyno mills, agitator mills, dynamic mills and the like can be used. These dispersing devices use grinding media such as balls and beads to perform fine grinding and dispersion by impact crushing, friction, shearing, shear stress, and the like.

As the beads used in the wet media dispersion type device, for example, balls made of glass, alumina, zircon, zirconia, steel, flint stone, etc. as raw materials can be used, and particularly those made of zirconia or zircon can be used. preferable. As for the size of the beads, beads with a diameter of about 1 to 2 mm are usually used, but in the present invention, for example, beads with a diameter of about 0.1 to 1.0 mm are preferably used.

Various materials such as stainless steel, nylon, and ceramics can be used for the disks and inner walls of the container used in the wet media dispersion type device. is preferably a disk or inner wall of the container.

[5] Other Additives The protective layer according to the present invention contains [1] a polyfunctional polymerizable compound having hole-transport properties, a monofunctional polymerizable compound having hole-transport properties, and [2] hole-transport properties. In addition to the polyfunctional polymerizable compound, [3] photopolymerization initiator, and [4] inorganic particles, other components may be contained, for example, known charge transport substances, various antioxidants, Various lubricant particles such as fluorine atom-containing resin particles can also be added.

As a known charge-transporting substance, for example, charge-transporting substances described in paragraphs [0064] to [0108] of JP-A-2018-124489 can be used.

Examples of fluorine atom-containing resin particles include tetrafluoroethylene resin, trifluoroethylene chloride resin, hexafluoroethylene chloride propylene resin, vinyl fluoride resin, vinylidene fluoride resin, difluorodichloride ethylene resin, and It is preferable to appropriately select one or more of these copolymers, and tetrafluoroethylene resin and vinylidene fluoride resin are particularly preferable.

(Lubricant particles)
Examples of lubricant particles include fluorine atom-containing resin particles. Examples of the fluorine atom-containing resin particles include tetrafluoroethylene resin, trifluoroethylene chloride resin, hexafluoroethylene chloride propylene resin, vinyl fluoride resin, vinylidene fluoride resin, difluorodichloride ethylene resin, and these resins. It is preferable to appropriately select one or more of the copolymer particles of (1), and tetrafluoroethylene resin particles and vinylidene fluoride resin particles are particularly preferable.

The number average primary particle size of the lubricant particles is preferably in the range of 0.01 to 1 μm, more preferably in the range of 0.05 to 0.5 μm.
In the present invention, the number average primary particle size of lubricant particles is measured as follows.
That is, a scanning electron microscope "JSM-7500F" (manufactured by JEOL Ltd.) was used to take an enlarged photograph of 10,000 times, and 300 lubricant particles were randomly captured by a scanner. Calculation is performed using a processing analysis device "LUZEX AP" (software version Ver. 1.32, manufactured by Nireco Corporation).

The molecular weight of the resin that constitutes the lubricant particles can be appropriately selected and is not particularly limited.

The content of the lubricant particles is preferably in the range of 0.1 to 20% by mass, more preferably in the range of 0.2 to 10% by mass in the protective layer-forming coating liquid.

(solvent)
Solvents used in step (4-1) include, for example, methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butanol, t-butanol, sec-butanol, benzyl alcohol, toluene, xylene, methylene chloride, methyl ethyl ketone. , methyl isopropyl ketone, cyclohexane, ethyl acetate, butyl acetate, methyl cellosolve, ethyl cellosolve, tetrahydrofuran, 1-dioxane, 1,3-dioxolane, pyridine and diethylamine, and the like.

The liquid viscosity of the protective layer-forming coating liquid is preferably in the range of 5 to 50 mP·s, more preferably in the range of 10 to 25 mP·s.
If the viscosity of the protective layer-forming coating liquid is too low, coating unevenness may occur, and it may not be possible to form a protective layer having a desired layer thickness and a uniform layer thickness. . On the other hand, when the protective layer-forming coating liquid has an excessively high liquid viscosity, the protective layer-forming coating liquid does not have good fluidity, causing the liquid to run out on the coating surface, resulting in a uniform uncured film. It may not be possible to form
The liquid viscosity of the protective layer-forming coating liquid is measured using an "E-type viscometer VISCONIC ELD type" (manufactured by Tokyo Keiki Co., Ltd.).

In the uncured film forming step (4-1), examples of methods for applying the protective layer forming coating liquid include dip coating, spray coating, spinner coating, bead coating, blade coating, beam coating, Known methods such as the slide hopper method can be used. Among these, the coating method by the slide hopper method is preferable.

The uncured film coated with the protective layer forming coating liquid in the uncured film forming step (4-1) is dried to remove the solvent.
Drying of the uncured film may be performed before, after, or during the light irradiation step (4-2) described below, and can be appropriately selected by combining these. After primary drying to the extent that the fluidity of the film is lost, the light irradiation step (4-2) is performed, and then secondary drying is performed to make the amount of volatile substances in the protective layer a specified amount. is preferred.
The method for drying the uncured film can be appropriately selected depending on the type of solvent, the thickness of the protective layer to be formed, etc. The drying temperature is, for example, preferably room temperature to 180° C., more preferably 80 to 80° C. 140°C. The drying time is, for example, preferably 1 to 200 minutes, more preferably 5 to 100 minutes.

[Step (4-2): Light irradiation step]
In this step (4-2), the uncured film of the workpiece W is irradiated with light using the above-described light irradiation device, and the polymerizable compound in the uncured film is polymerized by irradiating with light such as ultraviolet rays. It is a step of forming a protective layer by curing with a heat. In the following description, the case of using the light irradiation device 100 (see FIG. 1) in which the light emitting diodes are arranged in a ring shape as described above will be described as an example. A vertical light irradiation device 300 (see FIG. 4) in which the

Specifically, as shown in FIG. 3, first, a work W having an uncured film formed on a photosensitive layer on a cylindrical conductive support is placed in a work transport path space S in a machine frame 30. The work W is lowered from above until the upper end surface of the work W is positioned at the center level position of the gas discharge port 25 (see FIG. 3(a)).
Next, while nitrogen gas is discharged from the gas discharge port 25 and light is emitted from the light exit window 15, the work is transported upward at a constant lifting speed in the work transport path space S (see FIG. 3B).
Further, the lifting of the work W is stopped in the work transport path space S after the lower end surface of the work W passes the uppermost end of the light exit window 15 (see FIG. 3(c)) to form a protective layer. obtain a photoreceptor.

The outer diameter of the work W is preferably within a range of 25 to 35 mm, for example.
It is preferable that the distance between the work W and the light exit window 15 is within a range of 1 to 10 mm, for example.
Further, it is preferable that the distance between the workpiece W and the gas discharge port 25 is within a range of 1 to 5 mm, for example.
Further, the lifting speed of the workpiece W can be set within a range of 1 to 30 mm/sec, for example.

The flow rate of the nitrogen gas may be any flow rate that supplies nitrogen gas in an amount such that the oxygen gas concentration in the portion around the portion of the uncured film that is irradiated with light is 500 ppm or less. Although it varies depending on the size of the cross-sectional area of 21, it is preferable that the flow rate is constant, for example, 0.5 to 5 L/min.
By setting the flow rate of the nitrogen gas within the above range, the oxygen gas concentration around the portion of the uncured film irradiated with light can be reliably suppressed. On the other hand, if the nitrogen gas flow rate is too low, the oxygen gas concentration around the portion of the uncured film that is irradiated with light cannot be reliably suppressed, and uneven curing occurs in the formed protective layer. There is a risk. In addition, if the flow velocity of nitrogen gas is too high, turbulence is generated in the air flow and surrounding oxygen is involved, making it difficult to control the oxygen concentration in the vicinity of the portion of the uncured film irradiated with light to a desired level. , there is a risk of uneven curing.

The light irradiation conditions for curing the uncured film are such that the light energy from a light emitting diode as a light source is the formula (I) (500 mW/cm ² < peak irradiance on photoreceptor ≤ 25000 mW/cm ²
) is satisfied.
The peak irradiance can be controlled by adjusting the output (%) of the light source. For example, it is preferably within the range of 10 to 100% from the standpoint of noise prevention.
Moreover, it is preferable that the light energy satisfies the condition represented by the formula (II) (1 J/cm ² ≤ integrated energy on photoreceptor ≤ 100 J/cm ² ).
The integrated energy can be controlled by adjusting the peak irradiance and irradiation time. Specifically, the irradiation time is preferably within the range of 0.04 to 200 seconds.
Further, the irradiation time is controlled, for example, by the workpiece pull-up speed in the case of a ring-type light irradiation device, and by the rotation speed of the work in the case of a vertical (line-shaped) light irradiation device. can be done. The speed of pulling up the work is preferably in the range of 1 to 100 mm/sec, and the rotational speed of the work is preferably in the range of 1 to 100 rpm.

The layer thickness of the protective layer formed in the light irradiation step (4-2) is preferably in the range of 0.2 to 10 μm, more preferably in the range of 0.5 to 5 μm.

[Electrophotographic photoreceptor]
The electrophotographic photoreceptor of the present invention is manufactured by the method for manufacturing an electrophotographic photoreceptor of the present invention.
Specifically, as described above, after forming a coating film as a protective layer, the coating film is cured by irradiation of light energy using a light emitting diode as a light source to form a protective layer. , a novel electrophotographic photoreceptor is produced by satisfying the conditions represented by the formula (I).

Conventionally, it is known that the wear resistance of a photoreceptor is correlated to some extent with the universal hardness value and the elastic deformation rate.
Therefore, regarding the electrophotographic photoreceptor produced by the electrophotographic photoreceptor production method of the present invention and the electrophotographic photoreceptor produced by the conventional production method, the universal hardness value and the elastic deformation rate were calculated by the following calculation method. Calculated.
As a result, the photoreceptor obtained by the method for manufacturing a photoreceptor of the present invention has the same universal hardness value and elastic deformation rate as those of the photoreceptor manufactured by the conventional method. From the results of Examples, it was found that an effect of abrasion resistance was obtained.
In addition, the photoreceptor obtained by the method for producing a photoreceptor of the present invention is considered to have a difference in the polymerization state such as the molecular weight of the polymerizable compound contained in the protective layer and the crosslink density. It was not possible to grasp the state of polymerization such as measurement.
As described above, regarding the photoreceptor manufactured by the method for manufacturing a photoreceptor of the present invention, at present, no physical property value or chemical structure correlated with the effect of the present invention has been found.
That is, the polymer contained in the protective layer according to the present invention cannot be directly specified by its structure or properties at the time of filing the application, and the polymer composition contained in the protective layer is obtained. It is possible to specify for the first time by the process (manufacturing method) for.

－測定条件－
測定機：超微小硬度計「Ｈ－１００Ｖ」（フィッシャー・インストルメンツ社製）
圧子形状：ビッカース圧子（ａ＝１３６°）
測定環境：２５℃、相対湿度５０％ＲＨ
最大試験荷重：２ｍＮ
荷重速度：２ｍＮ／１０ｓｅｃ
最大荷重クリープ時間：５秒
除荷速度：２ｍＮ／１０ｓｅｃ (Calculation method of universal hardness value (HU))
The universal hardness value and the elastic deformation rate were measured at arbitrary five points from the image forming area of the protective layer of the photoreceptor as shown below, and the average value was obtained.
The universal hardness value (HU) is measured using an ultra-micro hardness tester "H-100V" (manufactured by Fisher Instruments) under the following measurement conditions, and the universal hardness value is determined by the following formulas (X) and (Y). Hardness values were calculated.

-Measurement condition-
Measuring machine: Ultra micro hardness tester "H-100V" (manufactured by Fisher Instruments)
Indenter shape: Vickers indenter (a = 136°)
Measurement environment: 25°C, relative humidity 50% RH
Maximum test load: 2mN
Load speed: 2mN/10sec
Maximum load creep time: 5 seconds Unloading speed: 2 mN/10 sec

(Method for calculating elastic deformation rate)
The elastic deformation rate was measured using a Fischerscope H-100 (manufactured by Fisher Instruments) under the conditions of 25° C. and 50% RH. Using a Vickers square pyramidal diamond indenter, a load of 2 mN was applied to the outermost layer and the lower layer of the photoreceptor for a load time of 10 seconds, held for 5 seconds, and then unloaded for 10 seconds to measure the indentation depth and load. , as shown in FIG. 6 (A→B→C).
The work of elastic deformation Welast is represented by the area surrounded by CBDC in FIG. 6, and the work of plastic deformation Wplast is represented by the area surrounded by ABCA in FIG. , Elastic deformation rate (%) was obtained from (Welast/(Welast+Wplast))×100.

[Image forming apparatus]
The photoreceptor obtained by the production method of the present invention can be used in various known electrophotographic image forming apparatuses such as a monochrome image forming apparatus and a full-color image forming apparatus.
An image forming apparatus using the photoreceptor obtained by the production method of the present invention includes, for example, a charging means for applying a uniform charging potential to the organic photoreceptor and an electrostatic charge on the organic photoreceptor to which the uniform charging potential is applied. Exposure means for forming an electrostatic latent image, developing means for developing the electrostatic latent image with toner to visualize it into a toner image, transfer means for transferring the toner image onto a transfer material, and the toner image on the transfer material. and a cleaning means for removing toner remaining on the photoreceptor.

EXAMPLES The present invention will be specifically described below with reference to Examples, but the present invention is not limited to these. In the following examples, unless otherwise specified, operations were performed at room temperature (25°C). Moreover, unless otherwise specified, "%" and "parts" mean "% by mass" and "parts by mass" respectively.

[Preparation of Photoreceptor 1]
Photoreceptor 1 was produced as follows.
A conductive support was prepared by cutting the surface of a cylindrical aluminum support.
<Middle layer>
An intermediate layer-forming coating solution having the following composition was prepared.
Binder resin: Polyamide resin "X1010" (manufactured by Daicel-Evonik)
1.0 part by mass
Metal oxide fine particles: Titanium dioxide "SMT500SAS" (manufactured by Tayka)
1.1 parts by mass Solvent: ethanol 20 parts by mass Using a sand mill as a dispersing machine, dispersion was carried out in batch mode for 10 hours.
The above coating solution was applied onto the support by dip coating so as to give a film thickness of 2 μm after drying at 110° C. for 20 minutes.

<Charge generation layer>
Charge-generating material: titanyl phthalocyanine pigment (a titanyl phthalocyanine pigment having a maximum diffraction peak at at least 27.3° in Cu-Kα characteristic X-ray diffraction spectrum measurement)
20 parts by mass Binder resin: Polyvinyl butyral resin "#6000-C" (manufactured by Denki Kagaku Kogyo Co., Ltd.)
10 parts by mass Solvent: t-butyl acetate 700 parts by mass 4-methoxy-4-methyl-2-pentanone
300 parts by mass were mixed and dispersed for 10 hours using a sand mill to prepare a coating liquid for forming a charge generation layer. This coating solution was applied onto the intermediate layer by a dip coating method to form a charge generation layer having a dry film thickness of 0.3 μm.

<Charge transport layer>
Charge transport material: CTM "Compound X below" 150 parts by mass Binder: Polycarbonate "Z300" (manufactured by Mitsubishi Gas Chemical Company, Inc.)
300 parts by mass Antioxidant: "Irganox (registered trademark) 1010" (manufactured by BASF Japan)
6 parts by mass Solvent: toluene/tetrahydrofuran = 1/9% by volume
2000 parts by mass Additive: silicone oil "KF-54" (manufactured by Shin-Etsu Chemical Co., Ltd.)
1 part by mass was mixed and dissolved to prepare a coating liquid for forming a charge transport layer. This coating solution was dried at 110° C. for 60 minutes by dip coating on the charge generation layer to form a charge transport layer having a thickness of 20 μm.

<Protective layer>
Hole-transporting compound: Exemplified compound 1-13 100 parts by mass Polyfunctional polymerizable compound that is not hole-transporting: glycerin triacrylate (GTA)
115 parts by mass polymerization initiator [1] (bis (2,4,6-trimethylbenzoyl)-phenylphosphine oxide: "Irgacure 819" (manufactured by BASF Japan))
13 parts by mass Solvent: Isopropyl alcohol 500 parts by mass Tetrahydrofuran 100 parts by mass The above components were mixed and dissolved in the dark with stirring to prepare a coating solution for forming a protective layer (light shielded during storage). Using a circular slide hopper coating machine, a protective layer was coated on the photoreceptor on which the coating liquid up to the charge transport layer had been previously prepared.
After coating, after drying for 20 minutes at room temperature (solvent drying step), in the ring-shaped light irradiation device shown in FIG. The coating film was irradiated with light using the apparatus. The irradiation distance from the coating film to the UV-LED chip was set to 5 mm, and irradiation was performed so as to achieve the peak irradiance and irradiation time shown in the table below (ultraviolet curing step) to obtain a protective layer with a thickness of 3 μm. The irradiation distance is the shortest distance from the UV-LED chip to the coating film.

[Preparation of photoreceptors 2 to 13]
Photoreceptors 2 to 13 were obtained in the same manner as Photoreceptor 1 except that the photoreceptor material and curing conditions were changed as shown in the table below.
Further, in Table I, the “vertical” irradiation device is the device using UV-LED as a light source in the vertical irradiation device shown in FIG. In the vertical irradiation apparatus shown in FIG. 4, this apparatus uses a mercury xenon lamp as a light source. Also, the maximum emission maximum wavelength of each light source is as shown in Table I below.
The photoreceptor materials used in Table I are as follows.

[Preparation of Fixed Image and Stereoscopic Image]
As an image forming apparatus, "bizhub C360 (bizhub is a registered trademark of the same company)" manufactured by Konica Minolta, Inc. was used. The bizhub C360 is a multi-function peripheral (MFP) that employs a contact charging system, laser exposure with a wavelength of 780 nm, intermediate transfer that performs reversal development, and a tandem system.

[evaluation]
<Potential stability test (in-plane density unevenness)>
Under the environment of a temperature of 20° C. and a relative humidity of 50% RH, images were continuously formed on 1,000,000 sheets of A4-size neutral paper each with a print rate of 5%.
Then, in an environment with a temperature of 10 ° C. and a relative humidity of 20% RH, a monochrome halftone image (average relative reflection density measured with a Macbeth densitometer is 0 .4 image) was formed. A1, a2, . Similarly, a total of 8 points at intervals of 33 mm from 1 to 8 were defined as b1, b2, . . .
The tolerance (difference between the maximum value and the minimum value) of these 16 measured values was calculated and rank-evaluated according to the following evaluation criteria. It should be noted that the smaller the tolerance of the measured values, the smaller the density unevenness in the paper surface.
(standard)
A: The tolerance of the measured values is less than 0.01, and there is almost no density unevenness. B: The tolerance of the measured values is 0.01 or more and less than 0.02, and density unevenness occurs, but it is small and is not a problem for practical use. C: The tolerance of the measured values is 0.02 or more and less than 0.04, and density unevenness occurs, but is practical. D: The tolerance of the measured values is 0.04 or more, and clear density unevenness occurs. , impractical

<Uneven wear test>
The thickness of the protective layer before and after a printing endurance test in which 150,000 sheets of A4 images with a Bk printing rate of 5.0% are printed on A4 size neutral paper under the conditions of a temperature of 30 ° C. and a humidity of 80% RH. It was measured and evaluated by calculating the loss amount of the film thickness.
The film thickness of the protective layer is measured at intervals of 5 mm in the axial direction and every 120° in the circumferential direction at the uniform film thickness portion (excluding the film thickness profile of the film thickness variation portion at the front and rear ends of the application). Let the average value of the measured values be the film thickness profile of the protective layer in the axial direction. Then, the difference between the maximum value and the minimum value of the film thickness profile in the axial direction was defined as the amount of film thickness variation. As a film thickness measuring device, an eddy current type film thickness measuring device “EDDY560C” (manufactured by HELMUT FISCHER GMBTE CO) was used.
(standard)
A: The amount of film thickness variation is less than 0.2, and there is almost no density unevenness. B: The amount of film thickness variation is 0.2 or more and less than 0.4, and density unevenness occurs, but it is small and has no practical problem. C: The amount of film thickness variation is 0.4 or more and less than 0.6, and density unevenness occurs, but is practicable. D: The amount of film thickness variation is 0.6 or more, and is not practical.

As shown in the above results, the photoreceptors manufactured by the manufacturing method of the present invention are found to have superior abrasion resistance and good electrical properties as compared to those of the comparative examples.

REFERENCE SIGNS LIST 11 light source 12 light guide member 13 accommodation space 15 light exit window 16 triangular prism 30 machine frame 100 light irradiation device S work transport path space W work 200 electrophotographic photoreceptor 201 conductive support 202 intermediate layer 203 photosensitive layer 203a charge generation layer 203b charge transport layer 204 surface protective layer PS metal oxide particles 300 light irradiation device 301 vacuum chamber 302 light source

Claims (6)

A method for producing an electrophotographic photoreceptor having at least a photosensitive layer and a protective layer on a conductive support,
A step of forming a coating film as a protective layer using a coating liquid containing a polymerizable compound;
After forming the coating film, a step of curing the coating film by irradiation with light energy using a light emitting diode as a light source to form a protective layer,
A method for producing an electrophotographic photoreceptor, wherein the light energy satisfies the condition represented by the following formula (I).
Formula (I):
500 mW/cm ² <Peak irradiance on photoreceptor≦25000 mW/cm ² 2. The method for producing an electrophotographic photoreceptor according to claim 1, wherein the maximum emission wavelength of said light emitting diode is within a range of 360 to 405 nm. 3. The method for producing an electrophotographic photoreceptor according to claim 1, wherein the light energy satisfies the condition represented by the following formula (II).
(Formula II):
1 J/cm ² ≦ Cumulative energy on photoreceptor ≦ 100 J/cm ² A workpiece having a coated film of the photosensitive layer and the uncured protective layer formed on the vertically extending cylindrical conductive support surrounds the outer peripheral surface of the workpiece in the vertical transport path space. Light energy is emitted from the light emitting diodes arranged in a ring shape along the circumferential direction to cure the coating film and form the protective layer. The method for producing an electrophotographic photoreceptor according to any one of the above. 5. Any one of claims 1 to 4, wherein the protective layer of the electrophotographic photosensitive member contains a polymer of a hole-transporting compound having a structure represented by the following general formula (III): 1. The method for producing an electrophotographic photoreceptor according to claim 1.

[In general formula (III), Ar ¹ to Ar ⁴ may be the same or different, and each represents a substituted or unsubstituted aryl group. Ar ⁵ represents a substituted or unsubstituted aryl group or arylene group. D is -(-(CH ₂ )d-(O-(CH ₂ )f-)e-O-CO-C(H)=CH ₂ ) or -(-(CH ₂ )d-(O-( CH ₂ )f-) represents e—O—CO—C(CH ₃ )=CH ₂ ). c1 to c5 each independently represent 0, 1 or 2; k represents 0 or 1; d and f each independently represent an integer of 0 to 5; e represents 0 or 1; The total number of Ds (c1+c2+c3+c4+c5) is 1 or more. ] An electrophotographic photoreceptor manufactured by the method according to any one of claims 1 to 5.

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