JP7047552B2 - Positively charged electrophotographic photosensitive member, process cartridge, and image forming apparatus - Google Patents

Description

The present invention relates to a positively charged electrophotographic photosensitive member, a process cartridge, and an image forming apparatus.

Patent Document 1 describes "an electrophotographic photosensitive member having a substrate, an undercoat layer containing oxygen and gallium, and a photosensitive layer in this order from the substrate side."

Japanese Unexamined Patent Publication No. 2011-066908

For example, in a positively charged electrophotographic photosensitive member provided with an inorganic protective layer, the inorganic protective layer may be scratched. Increasing the thickness of the inorganic protective layer in order to increase the mechanical strength of the inorganic protective layer may increase the residual potential. On the other hand, when the stoichiometric ratio of the material forming the inorganic protective layer is reduced in order to suppress the increase in the residual potential, the sensitivity may decrease.

The subject of the present invention is only a layer in which the inorganic protective layer is 1.40 or more and 1.50 or less as the elemental composition ratio (oxygen / gallium) of oxygen and gallium in the positively charged electrophotographic photosensitive member provided with the inorganic protective layer. If it is composed of only layers having a volume resistivity of 2.0 × 10 ¹⁰ Ωcm or more, or if the inorganic protective layer is composed of an elemental composition ratio of oxygen and gallium (oxygen / gallium). ) Is composed of only layers having a volume resistivity of 1.10 or more and 1.30 or less, or a volume resistivity of 2.0 × 10 ⁷ Ωcm or more and 1.0 × 10 ¹⁰ Ωcm or less. It is an object of the present invention to provide a positively charged electrophotographic photosensitive member that suppresses an increase in residual potential while ensuring sensitivity even when the thickness of the entire inorganic protective layer is thicker than in the case of the above.

The above problem is solved by the following means.

<1>
With a conductive substrate,
The organic photosensitive layer provided on the conductive substrate and
The elemental composition ratio of the 13th group element and the oxygen to all the elements which are the inorganic protective layer provided on the organic photosensitive layer and contain the 13th group element and oxygen and constitute the inorganic protective layer. The first region in which the sum of the above is 0.70 or more and the element composition ratio (oxygen / Group 13 element) of the oxygen and the group 13 element is 1.10 or more and 1.30 or less, and A second region in which the elemental composition ratio (oxygen / Group 13 element) of the oxygen and the Group 13 element is 1.40 or more and 1.50 or less is provided on the organic photosensitive layer in this order. The second region is the top layer, the inorganic protective layer,
A positively charged electrophotographic photosensitive member equipped with.

<2>
With a conductive substrate,
The organic photosensitive layer provided on the conductive substrate and
The elemental composition ratio of the group 13 element and the oxygen to the inorganic protective layer provided on the organic photosensitive layer and containing the group 13 element and oxygen and constituting the inorganic protective layer. The first region where the sum of is 0.70 or more and the volume resistivity is 2.0 × 10 ⁷ Ωcm or more and 1.0 × 10 ¹⁰ Ωcm or less and the volume resistivity is 2.0 × 10 ¹⁰ Ωcm. The above-mentioned second region is provided on the organic photosensitive layer in this order, and the inorganic protective layer in which the second region is the uppermost layer and
A positively charged electrophotographic photosensitive member equipped with.

<3>
The positively charged electrophotographic photosensitive member according to <1> or <2>, wherein the Group 13 element is gallium.
<4>
The positively charged electrophotographic photosensitive member according to any one of <1> to <3>, wherein the thickness of the first region is thinner than the thickness of the second region.
<5>
The positively charged electrograph according to <4>, wherein the ratio of the thickness of the second region to the thickness of the first region (thickness of the second region / thickness of the first region) is 3 or more and 100 or less. Photoreceptor.
<6>
The positive according to <4> or <5>, wherein the thickness of the first region is 0.01 μm or more and 0.5 μm or less, and the thickness of the second region is 0.3 μm or more and 3.5 μm or less. Charged electrophotographic photosensitive member.
<7>
The positively charged electrophotographic photosensitive member according to any one of <1> to <6>, wherein the total thickness of the inorganic protective layer is 3 μm or more and 10 μm or less.
<8>
The positively charged electrophotographic photosensitive member according to claim 7, wherein the total thickness of the inorganic protective layer is 3 μm or more and 6 μm or less.
<9>
Item 3. The positively charged type according to any one of <1> to <8>, wherein the first region and the second region are repeatedly laminated in the order of the first region and the second region. Electrophotographic photosensitive member.
<10>
The positively charged electrophotographic photosensitive member according to <9>, wherein the number of repetitions repeated in the order of the first region and the second region is 1 or more and 10 times or less.
<11>
The positively charged electrophotographic photosensitive member according to any one of <1> to <10>, wherein the organic photosensitive layer has a layer containing a charge transport material, a binder resin, and silica particles.
<12>
The positively charged electrophotographic photosensitive member according to claim <11>, wherein the content of the silica particles is 40% by mass or more and 80% by mass or less with respect to the entire layer containing the charge transport material and the binder resin. ..
<13>
The positively charged electrophotographic photosensitive member according to any one of <1> to <12>, wherein the conductive substrate has a thickness of 1.5 mm or more.

<14>
The positively charged electrophotographic photosensitive member according to any one of <1> to <13> is provided.
A process cartridge that can be attached to and detached from the image forming device.
<15>
The positively charged electrophotographic photosensitive member according to any one of <1> to <13>, and the positively charged electrophotographic photosensitive member.
A charging means for charging the surface of the positively charged electrophotographic photosensitive member,
An electrostatic latent image forming means for forming an electrostatic latent image on the surface of the charged positively charged electrophotographic photosensitive member,
A developing means for developing an electrostatic latent image formed on the surface of the positively charged electrophotographic photosensitive member with a developer containing toner to form a toner image, and a developing means.
A transfer means for transferring the toner image to the surface of a recording medium,
An image forming apparatus.

According to the inventions <1> and <3>, in the positively charged electrophotographic photosensitive member provided with the inorganic protective layer, the inorganic protective layer has an elemental composition ratio (oxygen / gallium) of 1.40 or more of oxygen and gallium. Sensitivity is increased even when the thickness of the entire inorganic protective layer is thicker than when it is composed of only a layer having a thickness of 1.50 or less or a layer having a thickness of 1.10 or more and 1.30 or less. Provided is a positively charged electrophotographic photosensitive member that suppresses an increase in residual potential while ensuring.

According to the invention according to <2>, in the positively charged electrophotographic photosensitive member provided with the inorganic protective layer, only the layer having a volume resistivity of 2.0 × 10 ¹⁰ Ωcm or more, or 2.0 × 10 ⁷ Ωcm. A positively charged electrophotographic photosensitive member that suppresses an increase in residual potential while ensuring sensitivity is provided as compared with the case where the layer is composed of only a layer having a size of 1.0 × 10 ¹⁰ Ωcm or less.

According to the inventions of <4>, <5>, and <6>, in the inorganic protective layer, the decrease in sensitivity is suppressed as compared with the case where the thickness of the first region is the same as or thicker than the thickness of the second region. A positively charged electrophotographic photosensitive member is provided.
According to the inventions <7> and <8>, there is provided a positively charged electrophotographic photosensitive member in which the occurrence of scratches on the inorganic protective layer is suppressed as compared with the case where the thickness of the entire inorganic protective layer is less than 3 μm. To.
According to the invention according to <9>, the thickness of the entire inorganic protective layer is as compared with the case where the first region and the second region are repeatedly laminated in the order of the second region and the first region. Provided is a positively charged electrophotographic photosensitive member that suppresses an increase in residual potential while ensuring sensitivity even when the thickness becomes thick.
According to <10>, in the inorganic protective layer, the thickness of the entire inorganic protective layer is thicker than that in the case where the number of repetitions of repeatedly laminating the first region and the second region is less than one. However, a positively charged electrophotographic photosensitive member that suppresses an increase in residual potential while ensuring sensitivity is provided.
According to the inventions of <11> and <12>, when the organic photosensitive layer is a functionally separated photosensitive layer of a charge generating layer and a charge transporting layer, the charge transporting layer is a charge transporting material and a binder resin. Provided is a positively charged electrophotographic photosensitive member in which the occurrence of scratches on the inorganic protective layer is suppressed as compared with the case of containing only.
According to the invention according to <13>, there is provided a positively charged electrophotographic photosensitive member in which the generation of scratches on the inorganic protective layer is suppressed as compared with the case where the thickness of the conductive substrate is less than 1.5 μm.

According to the inventions according to <14> and <15>, in the positively charged electrophotographic photosensitive member provided with the inorganic protective layer, the inorganic protective layer has an elemental composition ratio (oxygen / gallium) of 1.40 or more of oxygen and gallium. When it is composed of only layers having a volume resistivity of 1.50 or less, or only layers having a volume resistivity of 2.0 × 10 ¹⁰ Ωcm or more, or as an elemental composition ratio (oxygen / gallium) of oxygen and gallium, 1 .When it is composed only of layers having a volume resistivity of 10 or more and 1.30 or less, or when it is composed only of layers having a volume resistivity of 2.0 × 10 ⁷ Ωcm or more and 1.0 × 10 ¹⁰ Ωcm or less. Provided by a process cartridge or an image forming apparatus provided with a positively charged electrophotographic photosensitive member that suppresses an increase in residual potential while ensuring sensitivity even when the thickness of the entire inorganic protective layer is thicker than that of the above. Will be done.

It is a schematic cross-sectional view which shows an example of the layer structure of the positive charge type electrophotographic photosensitive member of this embodiment. It is a schematic cross-sectional view which shows another example of the layer structure of the positive charge type electrophotographic photosensitive member of this embodiment. It is a schematic cross-sectional view which shows another example of the layer structure of the positive charge type electrophotographic photosensitive member of this embodiment. It is a schematic cross-sectional view which shows another example of the layer structure of the positive charge type electrophotographic photosensitive member of this embodiment. It is a schematic schematic diagram which shows an example of the film forming apparatus used for forming the inorganic protective layer of the positive charge type electrophotographic photosensitive member of this embodiment. It is a schematic schematic diagram which shows the example of the plasma generator used for forming the inorganic protective layer of the positive charge type electrophotographic photosensitive member of this embodiment. It is a schematic block diagram which shows an example of the image forming apparatus which concerns on this embodiment. It is a schematic block diagram which shows another example of the image forming apparatus which concerns on this embodiment.

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

[Positively charged electrophotographic photosensitive member]
The positively charged electrophotographic photosensitive member according to the first embodiment is a conductive substrate, an organic photosensitive layer provided on the conductive substrate, and an inorganic protective layer provided on the organic photosensitive layer. The sum of the element composition ratios of the 13th group element and the oxygen to all the elements containing the 13th group element and the oxygen and constituting the inorganic protective layer is 0.70 or more, and the oxygen and the 13th group element The first region where the elemental composition ratio (oxygen / Group 13 element) is 1.10 or more and 1.30 or less, and the elemental composition ratio (oxygen / Group 13 element) of oxygen and the Group 13 element are 1. A second region of .40 or more and 1.50 or less is provided on the organic photosensitive layer in this order, and an inorganic protective layer in which the second region is the uppermost layer is provided.

The positively charged electrophotographic photosensitive member according to the second embodiment is a conductive substrate, an organic photosensitive layer provided on the conductive substrate, and an inorganic protective layer provided on the organic photosensitive layer. The sum of the elemental composition ratios of the group 13 element and oxygen with respect to all the elements containing the group 13 element and oxygen and constituting the inorganic protective layer is 0.70 or more, and the volume resistivity is 2.0. A first region having a volume resistivity of × 10 ⁷ Ωcm or more and 1.0 × 10 ¹⁰ Ωcm or less and a second region having a volume resistivity of 2.0 × 10 ¹⁰ Ωcm or more are provided on the organic photosensitive layer in this order. A second region is provided with an inorganic protective layer, which is the uppermost layer.

Positive charge according to a first embodiment and a second embodiment (in the present specification, matters common to the first embodiment and the second embodiment are referred to as "the present embodiment"). Specifically, when the organic photosensitive layer is a single-layer type organic photosensitive layer, the type electrophotographic photosensitive member includes, for example, a charge generating material, a charge transporting material, and a binding resin.
On the other hand, when the organic photosensitive layer is a function-separated organic photosensitive layer, the organic photosensitive layer is preferably an organic photosensitive layer having a charge transport layer and a charge generation layer on a conductive substrate in this order. This charge transport layer contains, for example, a charge transport material and a binder resin. The charge transport layer may be composed of two or more layers.
In the following description, the positively charged electrophotographic photosensitive member may be simply referred to as an "electrophotographic photosensitive member".

Here, conventionally, a technique for forming an inorganic protective layer on an organic photosensitive layer is known.
The organic photosensitive layer has flexibility and tends to be easily deformed, while the inorganic protective layer tends to be hard but inferior in toughness. Therefore, scratches may occur on the inorganic protective layer.

For example, in the developing step, when carriers are scattered from the developing means and the scattered carriers adhere to the electrophotographic photosensitive member, the carriers reach the transfer position while adhering to the electrophotographic photosensitive member. Then, at the transfer position, the carrier is subjected to pressing pressure while being sandwiched between the electrophotographic photosensitive member and the transfer means. Therefore, the inorganic protective layer may have scratches (dent-like scratches, streak-like scratches, etc.) due to rubbing of the carrier between the electrophotographic photosensitive member and the transfer means, for example.

In order to improve the mechanical strength of the inorganic protective layer, for example, it is conceivable to increase the thickness of the inorganic protective layer. However, if the thickness of the inorganic protective layer is increased, electric charges are likely to be accumulated in the inorganic protective layer, so that the residual potential may increase.
On the other hand, in order to suppress the increase in the residual potential, it is conceivable to reduce the stoichiometric ratio of the material forming the inorganic protective layer. Inorganic protective layers with a small stoichiometric ratio tend to suppress charge accumulation. However, if the stoichiometric ratio of the material forming the inorganic protective layer is made small, the inorganic protective layer is easily colored, so that the exposure amount for lowering the potential becomes large. Therefore, the sensitivity may decrease.

On the other hand, the electrophotographic photosensitive member according to the present embodiment is a positively charged electrophotographic photosensitive member, and the inorganic protective layer contains Group 13 elements and oxygen, and all the elements constituting the inorganic protective layer. The sum of the elemental composition ratios of the group 13 element and oxygen with respect to the element is 0.70 or more.
In the electrophotographic photosensitive member of the first embodiment, the inorganic protective layer has a first element composition ratio (oxygen / Group 13 element) of oxygen and Group 13 elements of 1.10 or more and 1.30 or less. A region and a second region in which the oxygen / Group 13 element is 1.40 or more and 1.50 or less are provided on the photosensitive layer in this order. The second region is the uppermost layer of the inorganic protective layer.
Further, in the electrophotographic photosensitive member of the second embodiment, the inorganic protective layer has a first region having a volume resistivity of 2.0 × 10 ⁷ Ωcm or more and 1.0 × 10 ¹⁰ Ωcm or less, and a volume resistivity. A second region having a size of 2.0 × 10 ¹⁰ Ωcm or more is provided on the photosensitive layer in this order. The second region is the uppermost layer of the inorganic protective layer.

In the electrophotographic photosensitive member of the first embodiment, in the inorganic protective layer, a second region close to the stoichiometric ratio is formed on the first region having a small stoichiometric ratio. In the first region where the stoichiometric ratio is small, oxygen deficiency occurs, so that the charge easily moves. As a result, when an electric field is applied, electrons in the second region are supplied to the first region, so that the accumulation of electric charges is suppressed, and the potential tends to decrease. As a result, it is considered that the increase in the residual potential of the inorganic protective layer is suppressed. Further, the first region having a small stoichiometric ratio is more easily colored than the second region having a stoichiometric ratio. Since the second region formed on the first region that is easily colored is the uppermost layer of the inorganic protective layer, the decrease in light transmittance is suppressed, so that the decrease in sensitivity is suppressed. it is conceivable that.

Further, in the electrophotographic photosensitive member of the second embodiment, in the inorganic protective layer, a second region having a high volume resistivity is formed on the first region having a low volume resistivity. It is considered that in the first region, electrons easily flow due to the low resistance, and the electrons in the second region are supplied to the first region, so that charge accumulation is suppressed. As a result, it is considered that the increase in the residual potential is suppressed. Further, a point where the second region of high resistance, which is difficult to color, is the uppermost layer of the inorganic protective layer, and the first region of low resistance, in which charges are easily transferred, are formed below the second region. At this point, it is considered that the exposure amount for attenuating the surface potential is reduced. As a result, it is considered that the decrease in sensitivity is suppressed.

From the above, in the electrophotographic photosensitive member according to the present embodiment (first embodiment and second embodiment), the sensitivity is increased even when the thickness of the entire inorganic protective layer is increased by the above configuration. It is presumed that the rise in residual potential is suppressed while ensuring this.

By repeatedly laminating the first region and the second region on the photosensitive layer in this order from the photosensitive layer side, even when the thickness of the entire inorganic protective layer is increased, the sensitivity is further increased. While ensuring, the rise in residual potential is likely to be suppressed. When the first region and the second region are repeatedly laminated on the photosensitive layer (for example, the number of repetitions is 3 times or more and 10 times or less) to form an inorganic protective layer having a desired thickness, the thickness is thin. It will have a large number of first regions and second regions. Therefore, a large number of first regions in which electrons easily flow are formed in contact with the second region, so that the charge can be easily transferred in the entire inorganic protective layer, and the charge accumulation is reduced in the second region, so that the residual potential is reduced. It is thought that it will be easier to suppress the rise in electric charge. Further, since the thickness of the second region is thin, it is considered that the sensitivity can be easily secured.

Further, in the electrophotographic photosensitive member according to the present embodiment, even when the thickness of the entire inorganic protective layer is increased, the increase in the residual potential is suppressed while ensuring the sensitivity, so that the entire inorganic protective layer can be used. The thickness can be increased. Therefore, it becomes easy to suppress the occurrence of scratches on the inorganic protective layer. Further, since the outermost surface is formed in the above-mentioned second region, the mechanical strength of the inorganic protective layer is likely to be improved, and in this respect as well, the occurrence of scratches on the inorganic protective layer is likely to be suppressed.

Here, the organic photosensitive layer of the electrophotographic photosensitive member according to the present embodiment may contain silica particles. By using silica particles in the organic photosensitive layer, it is considered that the silica particles function as a reinforcing material for the organic photosensitive layer. Therefore, it is considered that the organic photosensitive layer is less likely to be deformed, so that cracking of the inorganic protective layer is suppressed.
For example, when the organic photosensitive layer is a single-layer type organic photosensitive layer, the organic photosensitive layer may further contain silica particles. Further, when the organic photosensitive layer is a function-separated organic photosensitive layer, the charge transport layer may further contain silica particles. However, when the charge transport layer is composed of two or more layers and silica particles are used, the charge transport layer of the layer constituting the surface (the uppermost layer of the charge transport layer) is a charge transport material and bound. It may be composed of a resin and silica particles.

Hereinafter, the electrophotographic photosensitive member according to this embodiment will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference numerals, and duplicate description will be omitted.
FIG. 1 is a schematic cross-sectional view showing an example of an electrophotographic photosensitive member according to the present embodiment. 2, FIG. 3, and FIG. 4 are schematic cross-sectional views showing another example of the electrophotographic photosensitive member according to the present embodiment, respectively.

The electrophotographic photosensitive member 7A shown in FIG. 1 is a so-called function-separating type photosensitive member (or laminated photosensitive member), in which an undercoat layer 1 is provided on a conductive substrate 4, and a charge transport layer 3 and charges are provided on the undercoat layer 1. It has a structure in which the generation layer 2 and the inorganic protective layer 5 are sequentially formed. In the electrophotographic photosensitive member 7A, the organic photosensitive layer is composed of the charge transport layer 3 and the charge generation layer 2. Further, in the inorganic protective layer 5, a first region 5A and a second region 5B are formed on the charge generation layer 2. The charge transport layer 3 is composed of a charge transport material and a binder resin, and contains silica particles as needed.

Similar to the electrophotographic photosensitive member 7A shown in FIG. 1, the electrophotographic photosensitive member 7B shown in FIG. 2 has a function in which the functions are separated into a charge generation layer 2 and a charge transport layer 3, and the functions of the charge transport layer 3 are further separated. It is a separable photoconductor. Further, the electrophotographic photosensitive member 7C shown in FIG. 3 contains a charge-generating material and a charge-transporting material in the same layer (single-layer organic photosensitive layer 6 (charge-generating / charge-transporting layer)).

In the electrophotographic photosensitive member 7B shown in FIG. 2, an undercoat layer 1 is provided on the conductive substrate 4, and a charge transport layer 3B, a charge transport layer 3A, a charge generation layer 2, and an inorganic protective layer 5 are provided on the undercoat layer 1. Have a structure in which electric charges are sequentially formed. In the electrophotographic photosensitive member 7B, the organic photosensitive layer is composed of the charge transport layer 3A, the charge transport layer 3B, and the charge generation layer 2.
Similar to the electrophotographic photosensitive member 7A shown in FIG. 1, the inorganic protective layer 5 has a first region 5A and a second region 5B formed on the charge generation layer 2. The charge transport layer 3A and the charge transport layer 3B are configured to include a charge transport material and a binder resin. Further, the charge transport layer 3A contains silica particles, if necessary. When silica particles are used, they are contained in the charge transport layer 3A, and the charge transport layer 3B may or may not contain silica particles.

The electrophotographic photosensitive member 7C shown in FIG. 3 has a structure in which an undercoat layer 1 is provided on a conductive substrate 4, and a single-layer organic photosensitive layer 6 and an inorganic protective layer 5 are sequentially formed on the undercoat layer 1. Is.
The single-layer organic photosensitive layer 6 contains a charge transport material and a binder resin, and if necessary, contains silica particles.

Similar to the electrophotographic photosensitive member 7A shown in FIG. 1, the electrophotographic photosensitive member 7D shown in FIG. 4 is provided with an undercoat layer 1 on a conductive substrate 4, and a charge transport layer 3 and a charge generation layer 2 are provided on the undercoat layer 1. , And the structure in which the inorganic protective layer 5 is sequentially formed. Further, similarly to the electrophotographic photosensitive member 7A shown in FIG. 1, in the inorganic protective layer 5, a first region 5A and a second region 5B are formed on the charge generation layer 2. However, in the electrophotographic photosensitive member 7D, the inorganic protective layer 5 is repeatedly laminated with the first region 5A and the second region 5B from the charge transport layer 3 side in this order. In the electrophotographic photosensitive member 7D, the number of repetitions in which the first region 5A and the second region 5B are laminated is composed of three times.
The charge transport layer 3 is composed of a charge transport material and a binder resin, and contains silica particles as needed. Further, the number of repetitions in which the first region 5A and the second region 5B are laminated is not limited to three, and may be four or more.

In each electrophotographic photosensitive member shown in FIGS. 1, 2, 3, and 4, the undercoat layer 1 may or may not be provided. Further, in each electrophotographic photosensitive member shown in FIGS. 1, 2 and 3, as in the electrophotographic photosensitive member 7D shown in FIG. 4, the first region 5A and the second region 5B are arranged in this order. It may be repeatedly laminated.

Hereinafter, each element will be described based on the electrophotographic photosensitive member 7A shown in FIG. 1 as a representative example. The reference numerals may be omitted for description.

(Conductive hypokeimenon)
Examples of the conductive substrate include metal plates containing metals (aluminum, copper, zinc, chromium, nickel, molybdenum, vanadium, indium, gold, platinum, etc.) or alloys (stainless steel, etc.), metal drums, metal belts, and the like. Can be mentioned. The conductive substrate may be, for example, a paper, a resin film, a belt or the like coated, vapor-deposited or laminated with a conductive compound (for example, a conductive polymer, indium oxide, etc.), a metal (for example, aluminum, palladium, gold, etc.) or an alloy. Can also be mentioned. Here, "conductivity" means that the volume resistivity is less than 10 ¹³ Ωcm.

When the electrophotographic photosensitive member is used for a laser printer, the surface of the conductive substrate has a centerline average roughness Ra of 0.04 μm or more and 0.5 μm for the purpose of suppressing interference fringes generated when irradiating the laser beam. It is preferable that the surface is roughened below. When non-interfering light is used as a light source, roughening to prevent interference fringes is not particularly necessary, but it is more suitable for extending the life because it suppresses the occurrence of defects due to the unevenness of the surface of the conductive substrate.

As a method of roughening, for example, wet honing performed by suspending an abrasive in water and spraying it on a conductive substrate, centerless grinding in which the conductive substrate is pressed against a rotating grindstone and continuously ground. , Anodizing treatment and the like.

As a method of roughening, the conductive or semi-conductive powder is dispersed in the resin without roughening the surface of the conductive substrate to form a layer on the surface of the conductive substrate. Another method is to roughen the surface with particles dispersed in the layer.

In the roughening treatment by anodizing, an oxide film is formed on the surface of the conductive substrate by anodizing in an electrolyte solution using a conductive substrate made of metal (for example, made of aluminum) as an anode. Examples of the electrolyte solution include sulfuric acid solution, oxalic acid solution and the like. However, the porous anodized film formed by anodizing is chemically active as it is, is easily contaminated, and has a large resistance fluctuation depending on the environment. Therefore, for the porous anodic oxide film, the micropores of the oxide film are closed by volume expansion due to the hydration reaction in pressurized steam or boiling water (a metal salt such as nickel may be added), and more stable hydration oxidation is performed. It is preferable to perform a sealing treatment to change the material.

The film thickness of the anodizing film is preferably, for example, 0.3 μm or more and 15 μm or less. When this film thickness is within the above range, the barrier property against injection tends to be exhibited, and the increase in the residual potential due to repeated use tends to be suppressed.

The conductive substrate may be treated with an acidic treatment liquid or a boehmite treatment.
The treatment with the acidic treatment liquid is carried out, for example, as follows. First, an acidic treatment liquid containing phosphoric acid, chromic acid and hydrofluoric acid is prepared. The blending ratio of phosphoric acid, chromic acid and phosphoric acid in the acidic treatment liquid is, for example, a range of 10% by mass or more and 11% by mass or less of phosphoric acid, a range of 3% by mass or more and 5% by mass or less of chromic acid, and a hydrofluoric acid. It is preferably in the range of 0.5% by mass or more and 2% by mass or less, and the concentration of these acids as a whole is preferably in the range of 13.5% by mass or more and 18% by mass or less. The treatment temperature is preferably 42 ° C. or higher and 48 ° C. or lower, for example. The film thickness of the coating is preferably 0.3 μm or more and 15 μm or less.

The boehmite treatment is carried out, for example, by immersing in pure water at 90 ° C. or higher and 100 ° C. or lower for 5 to 60 minutes, or by contacting with heated steam at 90 ° C. or higher and 120 ° C. or lower for 5 to 60 minutes. The film thickness of the coating is preferably 0.1 μm or more and 5 μm or less. This can be further anodized with an electrolyte solution having low film solubility such as adipic acid, boric acid, borate, phosphate, phthalate, maleate, benzoate, tartrate, and citrate. good.

The thickness (thickness) of the conductive substrate is preferably 1 mm or more, preferably 1.2 mm or more, in terms of ensuring the strength of the photoconductor and suppressing the occurrence of scratches on the inorganic protective layer. It is more preferably 1.5 mm or more. The upper limit of the thickness of the conductive substrate is not particularly limited, but for example, it is often 3.5 mm or less from the viewpoint of suppressing the occurrence of scratches on the inorganic protective layer and the operability or manufacturability of the photoconductor. It may be 3 mm or less, or less than 3 mm. When the thickness of the conductive substrate is within the above range, the bending of the conductive substrate is easily suppressed, and the generation of scratches on the inorganic protective layer is easily suppressed.

(Underlay layer)
The undercoat layer is, for example, a layer containing inorganic particles and a binder resin.

Examples of the inorganic particles include inorganic particles having a powder resistivity (volume resistivity) of 10 ² Ωcm or more and 10 ¹¹ Ωcm or less.
Among these, as the inorganic particles having the above resistance value, for example, metal oxide particles such as tin oxide particles, titanium oxide particles, zinc oxide particles, and zinc oxide particles are preferable, and zinc oxide particles are particularly preferable.

The specific surface area of the inorganic particles by the BET method is, for example, preferably 10 m ² / g or more.
The volume average particle size of the inorganic particles is, for example, preferably 50 nm or more and 2000 nm or less (preferably 60 nm or more and 1000 nm or less).

The content of the inorganic particles is, for example, preferably 10% by mass or more and 80% by mass or less, and more preferably 40% by mass or more and 80% by mass or less with respect to the binder resin.

The inorganic particles may be surface-treated. As the inorganic particles, those having different surface treatments or those having different particle diameters may be mixed and used in two or more kinds.

Examples of the surface treatment agent include a silane coupling agent, a titanate-based coupling agent, an aluminum-based coupling agent, a surfactant and the like. In particular, a silane coupling agent is preferable, and a silane coupling agent having an amino group is more preferable.

Examples of the silane coupling agent having an amino group include 3-aminopropyltriethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, and N-2- (aminoethyl) -3-amino. Examples thereof include, but are not limited to, propylmethyldimethoxysilane, N, N-bis (2-hydroxyethyl) -3-aminopropyltriethoxysilane, and the like.

Two or more kinds of silane coupling agents may be mixed and used. For example, a silane coupling agent having an amino group may be used in combination with another silane coupling agent. Examples of other silane coupling agents include vinyltrimethoxysilane, 3-methacryloxypropyl-tris (2-methoxyethoxy) silane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, and 3-glyceride. Sidoxypropyltrimethoxysilane, vinyltriacetoxysilane, 3-mercaptopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, N-2-( Aminoethyl) -3-aminopropylmethyldimethoxysilane, N, N-bis (2-hydroxyethyl) -3-aminopropyltriethoxysilane, 3-chloropropyltrimethoxysilane, etc., but are limited thereto. It's not a thing.

The surface treatment method using a surface treatment agent may be any known method, and may be either a dry method or a wet method.

The treatment amount of the surface treatment agent is, for example, preferably 0.5% by mass or more and 10% by mass or less with respect to the inorganic particles.

Here, it is preferable that the undercoat layer contains an electron acceptor compound (acceptor compound) together with the inorganic particles from the viewpoint of enhancing the long-term stability of the electrical characteristics and the carrier blocking property.

Examples of the electron-accepting compound include quinone compounds such as chloranyl and bromoanyl; tetracyanoquinodimethane compounds; 2,4,7-trinitrofluorenone, 2,4,5,7-tetranitro-9-fluorenone and the like. Fluolenone compounds of; 2- (4-biphenyl) -5- (4-t-butylphenyl) -1,3,4-oxadiazole, 2,5-bis (4-naphthyl) -1,3,4- Oxadiazole compounds such as oxadiazole, 2,5-bis (4-diethylaminophenyl) -1,3,4 oxadiazole; xanthone compounds; thiophene compounds; 3,3', 5,5'tetra- Examples thereof include an electron transporting substance such as a diphenoquinone compound such as t-butyldiphenoquinone; and the like.
In particular, as the electron accepting compound, a compound having an anthraquinone structure is preferable. As the compound having an anthraquinone structure, for example, a hydroxyanthraquinone compound, an aminoanthraquinone compound, an aminohydroxyanthraquinone compound and the like are preferable, and specifically, for example, anthraquinone, alizarin, quinizarin, anthralphin, purpurin and the like are preferable.

The electron-accepting compound may be dispersed and contained in the undercoat layer together with the inorganic particles, or may be contained in a state of being attached to the surface of the inorganic particles.

Examples of the method for adhering the electron-accepting compound to the surface of the inorganic particles include a dry method and a wet method.

In the dry method, for example, while stirring inorganic particles with a mixer having a large shearing force, an electron-accepting compound dissolved directly or in an organic solvent is dropped and sprayed with dry air or nitrogen gas to obtain an electron-accepting compound. This is a method of adhering to the surface of inorganic particles. When dropping or spraying the electron-accepting compound, it is preferable to carry out at a temperature equal to or lower than the boiling point of the solvent. After the electron accepting compound is dropped or sprayed, it may be further baked at 100 ° C. or higher. The printing is not particularly limited as long as the temperature and time at which the electrophotographic characteristics can be obtained.

In the wet method, for example, an electron-accepting compound is added while dispersing inorganic particles in a solvent by stirring, ultrasonic waves, a sand mill, an attritor, a ball mill, or the like, and after stirring or dispersing, the solvent is removed to obtain electrons. This is a method of adhering an accepting compound to the surface of inorganic particles. The solvent removing method is distilled off, for example, by filtration or distillation. After removing the solvent, baking may be further performed at 100 ° C. or higher. The printing is not particularly limited as long as the temperature and time at which the electrophotographic characteristics can be obtained. In the wet method, the water content of the inorganic particles may be removed before the electron-accepting compound is added. Examples thereof include a method of removing the water contained in the inorganic particles while stirring and heating in a solvent, and a method of removing the particles by azeotropically boiling with the solvent. Can be mentioned.

The electron-accepting compound may be attached before or after the surface treatment with the surface treatment agent is applied to the inorganic particles, and the electron-accepting compound may be attached and the surface treatment with the surface treatment agent may be performed at the same time.

The content of the electron-accepting compound is, for example, preferably 0.01% by mass or more and 20% by mass or less, preferably 0.01% by mass or more and 10% by mass or less with respect to the inorganic particles.

Examples of the binder resin used for the undercoat layer include acetal resin (for example, polyvinyl butyral), polyvinyl alcohol resin, polyvinyl acetal resin, casein resin, polyamide resin, cellulose resin, gelatin, polyurethane resin, polyester resin, and unsaturated polyester. Resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinyl acetate resin, vinyl chloride-vinyl acetate-maleic acid anhydride resin, silicone resin, silicone-alkyd resin, urea resin, phenol resin, phenol-formaldehyde resin, melamine resin, Known polymer compounds such as urethane resin, alkyd resin, and epoxy resin; zirconium chelate compound; titanium chelate compound; aluminum chelate compound; titanium alkoxide compound; organic titanium compound; known material such as silane coupling agent can be mentioned.
Examples of the binder resin used for the undercoat layer include a charge-transporting resin having a charge-transporting group, a conductive resin (for example, polyaniline, etc.) and the like.

Among these, as the binder resin used for the undercoat layer, a resin insoluble in the coating solvent of the upper layer is preferable, and in particular, a urea resin, a phenol resin, a phenol-formaldehyde resin, a melamine resin, a urethane resin, and an unsaturated polyester. Thermo-curable resins such as resins, alkyd resins, epoxy resins; with at least one resin selected from the group consisting of polyamide resins, polyester resins, polyether resins, methacrylic resins, acrylic resins, polyvinyl alcohol resins and polyvinyl acetal resins. A resin obtained by reacting with a curing agent is suitable.
When two or more of these binder resins are used in combination, the mixing ratio thereof is set as necessary.

The undercoat layer may contain various additives for improving electrical characteristics, environmental stability, and image quality.
Examples of the additive include known materials such as electron-transporting pigments such as polycyclic condensation type and azo type, zirconium chelate compounds, titanium chelate compounds, aluminum chelate compounds, titanium alkoxide compounds, organic titanium compounds, and silane coupling agents. Be done. The silane coupling agent is used for surface treatment of inorganic particles as described above, but may be further added to the undercoat layer as an additive.

Examples of the silane coupling agent as an additive include vinyltrimethoxysilane, 3-methacryloxypropyl-tris (2-methoxyethoxy) silane, 2- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, and 3-. Glycydoxypropyltrimethoxysilane, vinyltriacetoxysilane, 3-mercaptopropyltrimethoxysilane, 3-aminopropyltriethoxysilane, N-2- (aminoethyl) -3-aminopropyltrimethoxysilane, N-2- (Aminoethyl) -3-aminopropylmethyldimethoxysilane, N, N-bis (2-hydroxyethyl) -3-aminopropyltriethoxysilane, 3-chloropropyltrimethoxysilane and the like can be mentioned.

Examples of the zirconium chelate compound include zirconium butoxide, zirconium acetoacetate ethyl, zirconium triethanolamine, acetylacetonate zirconium butoxide, zirconium acetate zirconium butoxide, zirconium acetate, zirconium oxalate, zirconium lactate, zirconium phosphonate, zirconium octanoate, and the like. Examples thereof include zirconium naphthenate, zirconium laurate, zirconium stearate, zirconium isostearate, zirconium methacrylate butoxide, stearate zirconium butoxide, and isosterate zirconium butoxide.

Examples of the titanium chelate compound include tetraisopropyl titanate, tetranormal butyl titanate, butyl titanate dimer, tetra (2-ethylhexyl) titanate, titanium acetylacetonate, polytitanium acetylacetonate, titanium octylene glycolate, and titanium lactate ammonium salt. , Titanium Lactate, Titanium Lactate Ethyl Ester, Titanium Triethanol Aminate, Polyhydroxy Titanium Steerate and the like.

Examples of the aluminum chelate compound include aluminum isopropylate, monobutoxyaluminum diisopropyrate, aluminum butyrate, diethylacetacetate aluminum diisopropyrate, aluminum tris (ethylacetoacetate) and the like.

These additives may be used alone or as a mixture or polycondensate of multiple compounds.

The undercoat layer preferably has a Vickers hardness of 35 or more.
The surface roughness (ten-point average roughness) of the undercoat layer ranges from 1 / (4n) (n is the refractive index of the upper layer) to 1/2 of the exposure laser wavelength λ used to suppress the moire image. It should be adjusted to.
Resin particles or the like may be added to the undercoat layer to adjust the surface roughness. Examples of the resin particles include silicone resin particles and crosslinked polymethyl methacrylate resin particles. Further, the surface of the undercoat layer may be polished to adjust the surface roughness. Examples of the polishing method include buffing, sandblasting, wet honing, and grinding.

The formation of the undercoat layer is not particularly limited, and a well-known formation method is used. For example, a coating film of a coating liquid for forming an undercoat layer in which the above components are added to a solvent is formed, and the coating film is dried. And, if necessary, it is done by heating.

As the solvent for preparing the coating liquid for forming the undercoat layer, known organic solvents such as alcohol-based solvent, aromatic hydrocarbon solvent, halogenated hydrocarbon solvent, ketone-based solvent, ketone alcohol-based solvent, and ether-based solvent are used. Examples thereof include solvents and ester-based solvents.
Specific examples of these solvents include methanol, ethanol, n-propanol, iso-propanol, n-butanol, benzyl alcohol, methyl cellsolve, ethyl cell solve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, ethyl acetate, and the like. Examples thereof include ordinary organic solvents such as n-butyl acetate, dioxane, methanol, methylene chloride, chloroform, chlorobenzene and toluene.

Examples of the method for dispersing the inorganic particles when preparing the coating liquid for forming the undercoat layer include known methods such as a roll mill, a ball mill, a vibration ball mill, an attritor, a sand mill, a colloid mill, and a paint shaker.

Examples of the method of applying the coating liquid for forming the undercoat layer onto the conductive substrate include a blade coating method, a wire bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, and a curtain coating method. Ordinary methods such as.

The film thickness of the undercoat layer is set, for example, preferably in the range of 15 μm or more, more preferably 20 μm or more and 50 μm or less.

(Middle layer)
Although not shown, an intermediate layer may be further provided between the undercoat layer and the photosensitive layer.
The intermediate layer is, for example, a layer containing a resin. Examples of the resin used for the intermediate layer include acetal resin (for example, polyvinyl butyral), polyvinyl alcohol resin, polyvinyl acetal resin, casein resin, polyamide resin, cellulose resin, gelatin, polyurethane resin, polyester resin, methacrylic resin, and acrylic resin. Examples thereof include polymer compounds such as polyvinyl chloride resin, polyvinyl acetate resin, vinyl chloride-vinyl acetate-maleic anhydride resin, silicone resin, silicone-alkyd resin, phenol-formaldehyde resin, and melamine resin.
The intermediate layer may be a layer containing an organometallic compound. Examples of the organic metal compound used for the intermediate layer include organic metal compounds containing metal atoms such as zirconium, titanium, aluminum, manganese, and silicon.
The compounds used for these intermediate layers may be used alone or as a mixture or polycondensate of a plurality of compounds.

Among these, the intermediate layer is preferably a layer containing an organometallic compound containing a zirconium atom or a silicon atom.

The formation of the intermediate layer is not particularly limited, and a well-known forming method is used. For example, a coating film of a coating liquid for forming an intermediate layer in which the above components are added to a solvent is formed, and the coating film is dried and required. It is done by heating according to the above.
As a coating method for forming the intermediate layer, a usual method such as a dip coating method, a push-up coating method, a wire bar coating method, a spray coating method, a blade coating method, a knife coating method, and a curtain coating method is used.

The film thickness of the intermediate layer is preferably set in the range of 0.1 μm or more and 3 μm or less, for example. The intermediate layer may be used as the undercoat layer.

(Charge transport layer)
The charge transport layer is, for example, a layer containing a charge transport material and a binder resin. The charge transport layer may be a layer containing a polymer charge transport material. Further, the charge transport layer may contain silica particles, if necessary.

Examples of the charge transport material include quinone compounds such as p-benzoquinone, chloranil, bromanil and anthraquinone; tetracyanoquinodimethane compounds; fluorenone compounds such as 2,4,7-trinitrofluorenone; xanthone compounds; benzophenone compounds. Examples thereof include electron-transporting compounds such as cyanovinyl-based compounds and ethylene-based compounds. Examples of the charge transporting material include hole transporting compounds such as triarylamine-based compounds, benzidine-based compounds, arylalkane-based compounds, aryl-substituted ethylene-based compounds, stylben-based compounds, anthracene-based compounds, and hydrazone-based compounds. These charge transport materials may be used alone or in combination of two or more, but are not limited thereto.

As the charge transport material, a triarylamine derivative represented by the following structural formula (a-1) and a benzidine derivative represented by the following structural formula (a-2) are preferable from the viewpoint of charge mobility.

In the structural formula (a-1), Ar ^T1 , Ar ^T2 , and Ar ^T3 are independently substituted or unsubstituted aryl groups, respectively, —C ₆ H4-C ₍ ^RT4 ) = C ( ^RT5 ) (R). ^T6 ) or -C ₆ H ₄ -CH = CH-CH = C ( ^{RT7) (RT8 )} is shown. ^{RT4, RT5, RT6, RT7, and RT8 each independently represent a} hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group.
Examples of the substituent of each of the above groups include a halogen atom, an alkyl group having 1 or more and 5 or less carbon atoms, and an alkoxy group having 1 or more and 5 or less carbon atoms. Further, examples of the substituent of each of the above groups include a substituted amino group substituted with an alkyl group having 1 or more and 3 or less carbon atoms.

In the structural formula (a-2), ^RT91 and ^RT92 independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 or more and 5 or less carbon atoms, or an alkoxy group having 1 or more and 5 or less carbon atoms. ^RT101 , ^RT102 , ^RT111 and ^RT112 are independently substituted with a halogen atom, an alkyl group having 1 or more and 5 or less carbon atoms, an alkoxy group having 1 or more and 5 or less carbon atoms, and an alkyl group having 1 or more carbon atoms and 2 or less carbon atoms. The amino group, substituted or unsubstituted aryl group, -C ( ^RT12 ) = C ( ^RT13 ) ( ^RT14 ), or -CH = CH-CH = C ( ^RT15 ) ( ^RT16 ) is shown. ^RT12 , ^RT13 , ^RT14 , ^RT15 and ^RT16 each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group. Tm1, Tm2, Tn1 and Tn2 each independently indicate an integer of 0 or more and 2 or less.
Examples of the substituent of each of the above groups include a halogen atom, an alkyl group having 1 or more and 5 or less carbon atoms, and an alkoxy group having 1 or more and 5 or less carbon atoms. Further, examples of the substituent of each of the above groups include a substituted amino group substituted with an alkyl group having 1 or more and 3 or less carbon atoms.

Here, among the triarylamine derivative represented by the structural formula (a-1) and the benzidine derivative represented by the structural formula (a-2), in particular, "-C ₆ H ₄ -CH = CH-CH =". A triarylamine derivative having "C ( ^{RT7) (RT8)" and a benzidine derivative having "-CH = CH-CH = C (RT15) (RT16 ) " are} preferable from the viewpoint of charge transfer.

As the polymer charge transport material, known materials having charge transport properties such as poly-N-vinylcarbazole and polysilane are used. In particular, polyester-based polymer charge transport materials disclosed in JP-A-8-176293 and JP-A-8-208820 are particularly preferable. The polymer charge transport material may be used alone or in combination with a binder resin.

The charge transport layer may contain silica particles. The content of the silica particles is preferably 40% by mass or more and 80% by mass or less with respect to the entire charge transport layer containing the silica particles from the viewpoint of suppressing the generation of scratches on the inorganic protective layer. In the same respect, the lower limit of the content of the silica particles may be 45% by mass or more, or 50% by mass or more. Further, the upper limit of the content of the silica particles may be, for example, 75% by mass or less, or 70% by mass or less, from the viewpoint of dispersibility of the silica particles and the like.

Examples of the silica particles include dry silica particles and wet silica particles.
Examples of the dry silica particles include combustion method silica (hummed silica) obtained by burning a silane compound and explosive combustion method silica obtained by explosively burning metallic silicon powder.
Wet silica particles include wet silica particles obtained by a neutralization reaction between sodium silicate and mineral acid (precipitation silica particles synthesized / aggregated under alkaline conditions, gel silica particles synthesized / aggregated under acidic conditions), and acidic silicic acid. Examples thereof include colloidal silica particles (silica sol particles) obtained by making them alkaline and polymerizing them, and sol-gel process silica particles obtained by hydrolysis of an organic silane compound (for example, alkoxysilane).
Among these, silica particles have few silanol groups on the surface and have a low void structure from the viewpoint of suppressing image defects due to generation of residual potential and deterioration of other electrical characteristics (suppression of deterioration of fine line reproducibility). Method It is preferable to use silica particles.

The volume average particle size of the silica particles is, for example, preferably 20 nm or more and 200 nm or less. The lower limit of the volume average particle size of the silica particles may be 40 nm or more, or 50 nm or more. The lower limit of the volume average particle size of the silica particles may be 150 nm or less, 120 nm or less, or 110 nm or less.

For the volume average particle size of the silica particles, the silica particles are separated from the layer, 100 primary particles of the silica particles are observed at a magnification of 40,000 times by an SEM (Scanning Electron Microsphere) device, and the particles are analyzed by image analysis of the primary particles. The longest diameter and the shortest diameter of each are measured, and the equivalent diameter of the sphere is measured from this intermediate value. The 50% diameter (D50v) in the cumulative frequency of the obtained sphere equivalent diameter is obtained, and this is measured as the volume average particle diameter of the silica particles.

The surface of the silica particles may be surface-treated with a hydrophobizing agent. As a result, the silanol groups on the surface of the silica particles are reduced, and the generation of residual potential is easily suppressed.
Examples of the hydrophobizing agent include well-known silane compounds such as chlorosilane, alkoxysilane, and silazane.
Among these, as the hydrophobizing treatment agent, a silane compound having a trimethylsilyl group, a decylsilyl group, or a phenylsilyl group is desirable from the viewpoint of facilitating the suppression of the generation of residual potential. That is, the surface of the silica particles may have a trimethylsilyl group, a decylsilyl group, or a phenylsilyl group.
Examples of the silane compound having a trimethylsilyl group include trimethylchlorosilane, trimethylmethoxysilane, 1,1,1,3,3,3-hexamethyldisilazane and the like.
Examples of the silane compound having a decylsilyl group include decyltrichlorosilane, decyldimethylchlorosilane, and decyltrimethoxysilane.
Examples of the silane compound having a phenyl group include triphenylmethoxysilane and triphenylchlorosilane.

The condensation rate of the hydrophobized silica particles (the rate of Si—O—Si in the bond of SiO _4- in the silica particles: hereinafter also referred to as “condensation rate of the hydrophobizing agent”) is, for example, the surface of the silica particles. 90% or more, preferably 91% or more, and more preferably 95% or more with respect to the silanol group of the above.
When the condensation rate of the hydrophobizing agent is within the above range, the silanol groups of the silica particles are further reduced, and the generation of residual potential is easily suppressed.

The condensation rate of the hydrophobizing agent indicates the ratio of condensed silicon to the fully bondable site of silicon in the condensed portion detected by NMR, and is measured as follows.
First, the silica particles are separated from the layer. The separated silica particles were subjected to Si CP / MAS NMR analysis with Bruker's AVANCE III 400 to determine the peak area according to the number of SiO substitutions, and two substitutions (Si (OH) ₂ (0-Si) ₂ ) were obtained, respectively. -), 3-substitution (Si (OH) (0-Si) _3- ), 4-substitution (Si (0-Si) _4- ) values are set to Q2, Q3, Q4, and the condensation rate of the hydrophobic treatment agent is the formula. : (Q2 × 2 + Q3 × 3 + Q4 × 4) / 4 × (Q2 + Q3 + Q4).

The volume resistivity of the silica particles is, for example, preferably 10 ¹¹ Ω cm or more, preferably 10 ¹² Ω cm or more, and more preferably 10 ¹³ Ω cm or more.
When the volume resistivity of the silica particles is set in the above range, the deterioration of the electrical characteristics is suppressed.

The volume resistivity of the silica particles is measured as follows. The measurement environment is a temperature of 20 ° C. and a humidity of 50% RH.
First, the silica particles are separated from the layer. Then, the separated silica particles to be measured are placed on the surface of a circular jig on which a 20 cm ² electrode plate is arranged so as to have a thickness of about 1 mm or more and 3 mm or less to form a silica particle layer. The same 20 cm ² electrode plate as described above is placed on this, and the silica particle layer is sandwiched therein. In order to eliminate the voids between the silica particles, a load of 4 kg is applied on the electrode plate placed on the silica particle layer, and then the thickness (cm) of the silica particle layer is measured. Both electrodes above and below the silica particle layer are connected to an electrometer and a high voltage power generator. A high voltage is applied to both electrodes so that the electric field becomes a predetermined value, and the volume resistivity (Ωcm) of the silica particles is calculated by reading the current value (A) flowing at this time. The formula for calculating the volume resistivity (Ωcm) of silica particles is as shown in the following formula.
In the formula, ρ is the volume resistivity (Ωcm) of the silica particles, E is the applied voltage (V), I is the current value (A), I0 is the current value (A) at the applied voltage 0V, and L is the silica particle layer. Represents the thickness (cm) of each. In this evaluation, the volume resistivity when the applied voltage is 1000 V was used.
-Formula: ρ = E × 20 / (I-I0) / L

Examples of the binder resin used for the charge transport layer include a polycarbonate resin (a homopolymerized type such as bisphenol A, bisphenol Z, bisphenol C, and bisphenol TP, or a copolymerized type thereof), a polyallylate resin, and a polyester. Resin, methacrylic resin, acrylic resin, polyvinyl chloride resin, polyvinylidene chloride resin, polystyrene resin, acrylonitrile-styrene copolymer, acrylonitrile-butadiene copolymer, polyvinyl acetate resin, styrene-butadiene copolymer, vinyl chloride-acetate Vinyl copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, silicone resin, silicone-alkyd resin, phenol-formaldehyde resin, styrene-acrylic copolymer, atylene-alkyd resin, poly-N-vinylcarbazole resin , Polyvinyl butyral resin, polyphenylene ether resin and the like. One of these binder resins may be used alone or in combination of two or more.
The blending ratio of the charge transport material and the binder resin is preferably 10: 1 to 1: 5 in terms of mass ratio.

Among the above-mentioned binding resins, a polycarbonate resin (a homopolymerized type such as bisphenol A, bisphenol Z, bisphenol C, bisphenol TP, or a copolymerized type thereof) is preferable. One type of polycarbonate resin may be used alone, or two or more types may be used in combination. Further, in the same respect, it is more preferable to include the homopolymerized polycarbonate resin of bisphenol Z among the polycarbonate resins.

From the viewpoint of suppressing the generation of scratches on the inorganic protective layer, the binder resin may have, for example, a viscosity average molecular weight of 50,000 or less. It is often less than 50,000, often less than 45,000, and may be less than or equal to 35,000. The lower limit of the viscosity average molecular weight is preferably 20000 or more from the viewpoint of maintaining the characteristics as a binder resin.
From the viewpoint of suppressing the occurrence of scratches on the inorganic protective layer, it is preferable to use a binder resin having a viscosity average molecular weight of 50,000 or less and the above-mentioned silica particles in combination.

Here, the following one-point measurement method is used for measuring the viscosity average molecular weight of the binder resin.
First, the inorganic protective layer is peeled off from the photoconductor to be measured, and then the photosensitive layer to be measured is exposed. Then, a part of the photosensitive layer is scraped off to prepare a sample for measurement.
Next, the binder resin is extracted from the measurement sample. 1 g of the extracted binder resin is dissolved in 100 cm ³ of methylene chloride, and its specific viscosity ηsp is measured with a Ubbelohde viscometer in a measurement environment of 25 ° C. Then, the relational expression of ηsp / c = [η] + 0.45 [η] ² c (where c is the concentration (g / cm ³ )) is used to obtain the ultimate viscosity [η] (cm ³ / g). The viscosity average molecular weight Mv is obtained from the given formula, [η] = 1.23 × 10 ^-4 Mv ^0.83 .

The charge transport layer may also contain other well-known additives.

The formation of the charge transport layer is not particularly limited, and a well-known forming method is used. For example, a coating film of a coating liquid for forming a charge transport layer in which the above components are added to a solvent is formed, and the coating film is dried. , By heating as needed.

As a solvent for preparing the coating liquid for forming the charge transport layer, aromatic hydrocarbons such as benzene, toluene, xylene and chlorobenzene; ketones such as acetone and 2-butanone; methylene chloride, chloroform, ethylene chloride and the like. Examples thereof include halogenated aliphatic hydrocarbons; ordinary organic solvents such as cyclic or linear ethers such as tetrahydrofuran and ethyl ether. These solvents may be used alone or in admixture of two or more.

The coating methods for applying the coating liquid for forming a charge transport layer onto the charge generating layer include a blade coating method, a wire bar coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coating method, and a curtain. An ordinary method such as a coating method can be mentioned.

When particles (for example, silica particles or fluororesin particles) are dispersed in the coating liquid for forming a charge transport layer, the dispersion method includes, for example, media dispersion such as a ball mill, a vibrating ball mill, an attritor, a sand mill, and a horizontal sand mill. Machines and medialess dispersers such as agitators, ultrasonic dispersers, roll mills, and high-pressure homogenizers are used. Examples of the high-pressure homogenizer include a collision method in which a dispersion liquid is dispersed by a liquid-liquid collision or a liquid-wall collision in a high-pressure state, and a penetration method in which a dispersion is dispersed by penetrating a fine flow path in a high-pressure state.

The elastic modulus of the charge transport layer is, for example, preferably 5 GPa or more, preferably 6 GPa or more. When the elastic modulus of the charge transport layer is within the above range, cracking of the inorganic protective layer is likely to be suppressed.
In addition, in order to make the elastic modulus of the charge transport layer within the above range, for example, a method of adjusting the particle size and the content of the silica particles, a method of adjusting the type and the content of the charge transport material, and the like can be mentioned.

The elastic modulus of the charge transport layer is measured as follows.
First, the inorganic protective layer is peeled off to remove the charge generation layer, and then the layer to be measured is exposed. Then, a part of the layer is cut out with a cutter or the like to obtain a measurement sample.
For this measurement sample, a depth profile was obtained by the continuous rigidity method (CSM) (US Pat. No. 4,48,141) using Nano Indenter SA2 manufactured by MTS Systems, and the depth profile was obtained from the measured values of the indentation depth of 30 nm to 100 nm. Measure using the average value.

The film thickness of the charge transport layer is, for example, preferably 10 μm or more and 40 μm or less, preferably 10 μm or more and 35 μm or less, and more preferably 15 μm or more and 35 μm or less.
When the film thickness of the charge transport layer is within the above range, cracking of the inorganic protective layer and generation of residual potential are likely to be suppressed.

(Charge generation layer)
The charge generation layer is, for example, a layer containing a charge generation material and a binder resin. Further, the charge generation layer may be a vapor deposition layer of a charge generation material. The thin-film deposition layer of the charge generating material is suitable when a non-interfering light source such as an LED (Light Emitting Diode) or an organic EL (Electro-Luminence) image array is used.

Examples of the charge generating material include azo pigments such as bisazo and trisazo; condensed ring aromatic pigments such as dibromoanthhrone; perylene pigments; pyrrolopyrrole pigments; phthalocyanine pigments; zinc oxide; and trigonal selenium.

Among these, in order to correspond to laser exposure in the near infrared region, it is preferable to use a metal phthalocyanine pigment or a non-metal phthalocyanine pigment as the charge generating material. Specifically, for example, hydroxygallium phthalocyanine disclosed in JP-A-5-263007, JP-A-5-279591, etc .; chlorogallium phthalocyanine disclosed in JP-A-5-98181, etc .; JP-A-5. Dichlorotin phthalocyanine disclosed in JP-A-140472, JP-A-5-140473, etc .; titanylphthalocyanine disclosed in JP-A-4-1809873, etc. is more preferable.

On the other hand, in order to cope with laser exposure in the near-ultraviolet region, as a charge generating material, a condensed ring aromatic pigment such as dibromoanthanthrone; a thioindigo pigment; a porphyrazine compound; zinc oxide; a trigonal selenium; The bisazo pigments disclosed in JP-A-2004-78147 and JP-A-2005-181992 are preferable.

The above charge generating material may also be used when using a non-interfering light source such as an LED having a center wavelength of light emission of 450 nm or more and 780 nm or less, or an organic EL image array, but from the viewpoint of resolution, the photosensitive layer is 20 μm or less. When used in a thin film, the electric field strength in the photosensitive layer becomes high, and a decrease in charge due to charge injection from the substrate, so-called black spots, is likely to occur. This becomes remarkable when a charge generating material such as a trigonal selenium or a phthalocyanine pigment, which is a p-type semiconductor and tends to generate a dark current, is used.

On the other hand, when an n-type semiconductor such as a condensed ring aromatic pigment, a perylene pigment, or an azo pigment is used as the charge generating material, it is difficult to generate a dark current, and even a thin film can suppress image defects called black spots. .. Examples of the n-type charge generating material include compounds (CG-1) to (CG-27) described in paragraphs [0288] to [0291] of JP2012-1552282. Not limited.
The n-type is determined by using the normally used time-of-flight method, and is determined by the polarity of the flowing photocurrent, and the n-type is one in which electrons are more easily flowed as carriers than holes.

The binder resin used for the charge generation layer is selected from a wide range of insulating resins, and the binder resin is from organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinylanthracene, polyvinylpyrene, and polysilane. You may choose.
Examples of the binder resin include polyvinyl butyral resin, polyarylate resin (hypercondensate of bisphenol and aromatic divalent carboxylic acid, etc.), polycarbonate resin, polyester resin, phenoxy resin, vinyl chloride-vinyl acetate copolymer, and the like. Examples thereof include polyamide resin, acrylic resin, polyacrylamide resin, polyvinylpyridine resin, cellulose resin, urethane resin, epoxy resin, casein, polyvinyl alcohol resin, polyvinylpyrrolidone resin and the like. Here, "insulation" means that the volume resistivity is 10 ¹³ Ωcm or more.
These binder resins are used alone or in admixture of two or more.

The blending ratio of the charge generating material and the binder resin is preferably in the range of 10: 1 to 1:10 in terms of mass ratio.

The charge generation layer may also contain other well-known additives.

The formation of the charge generation layer is not particularly limited, and a well-known formation method is used. For example, a coating film of a coating liquid for forming a charge generation layer in which the above components are added to a solvent is formed, and the coating film is dried. Then, if necessary, heat it. The charge generation layer may be formed by vapor deposition of a charge generation material. The formation of the charge generation layer by thin film deposition is particularly suitable when a condensed ring aromatic pigment or a perylene pigment is used as the charge generation material.

Solvents for preparing the coating liquid for forming the charge generation layer include methanol, ethanol, n-propanol, n-butanol, benzyl alcohol, methyl cellsolve, ethyl cell solve, acetone, methyl ethyl ketone, cyclohexanone, methyl acetate, n acetate. -Butyl, dioxane, methanol, methylene chloride, chloroform, chlorobenzene, toluene and the like can be mentioned. These solvents may be used alone or in admixture of two or more.

As a method of dispersing particles (for example, a charge generating material) in a coating liquid for forming a charge generating layer, for example, a media disperser such as a ball mill, a vibrating ball mill, an attritor, a sand mill, a horizontal sand mill, a stirrer, or an ultrasonic disperser. , Roll mills, high pressure homogenizers and other medialess dispersers are used. Examples of the high-pressure homogenizer include a collision method in which a dispersion liquid is dispersed by a liquid-liquid collision or a liquid-wall collision in a high-pressure state, and a penetration method in which a dispersion liquid is dispersed by penetrating a fine flow path in a high-pressure state.
At the time of this dispersion, it is effective to set the average particle size of the charge generating material in the coating liquid for forming the charge generating layer to 0.5 μm or less, preferably 0.3 μm or less, and more preferably 0.15 μm or less. ..

As a method of applying the coating liquid for forming the charge generation layer on the undercoat layer (or on the intermediate layer), for example, a blade coating method, a wire bar coating method, a spray coating method, a dip coating method, a bead coating method, and an air knife coating Examples include the usual method such as a method and a curtain coating method.

The film thickness of the charge generation layer is set, for example, preferably in the range of 0.1 μm or more and 5.0 μm or less, and more preferably 0.2 μm or more and 2.0 μm or less.

(Inorganic protective layer)
-Composition of inorganic protective layer-
The inorganic protective layer in the electrophotographic photosensitive member of the present embodiment is made of the following materials.
That is, the sum of the elemental composition ratios of the group 13 element and oxygen to all the elements containing the group 13 element and oxygen and constituting the inorganic protective layer is 0.70 or more.
In particular, the material constituting the inorganic protective layer in the electrophotographic photosensitive member of the first embodiment has an element composition ratio (oxygen / Group 13 element) of oxygen and Group 13 elements of 1.10 or more and 1.30 or less. It has a first region and a second region in which the oxygen / Group 13 element is 1.40 or more and 1.50 or less. Then, the first region and the second region are provided on the photosensitive layer in this order, and the second region is the uppermost layer. The Group 13 element is preferably gallium in terms of suppressing an increase in the residual potential while ensuring sensitivity. Further, since the Group 13 element is gallium, it becomes easy to suppress the occurrence of scratches on the inorganic protective layer.

In the first region, the elemental composition ratio of oxygen and Group 13 elements (oxygen / Group 13 elements) is 1.20 or more and 1.30 or less in terms of suppressing the increase in residual potential while ensuring sensitivity. It is often 1.25 or more and 1.30 or less. In the same respect, in the second region, the elemental composition ratio (oxygen / Group 13 element) of oxygen and Group 13 elements is often 1.45 or more and 1.50 or less, and 1.47 or more and 1 It is preferably .50 or less.

Here, when each element composition ratio (oxygen / Group 13 element (particularly gallium)) is in the above range in the first region and the second region, it is easy to control the volume resistivity in each region. Become. That is, the volume resistivity in the first region is in the range of 2.0 × 10 ⁷ Ωcm or more and 1.0 × 10 ¹⁰ Ωcm or less, and the volume resistivity in the second region is 2 × 10 ¹⁰ Ωcm or more 1 It becomes easy to fill the range of 0.0 × 10 ¹¹ Ωcm or less. In this respect, the material constituting each region of the inorganic protective layer of the electrophotographic photosensitive member according to the second embodiment is a material constituting each region of the inorganic protective layer of the electrophotographic photosensitive member according to the first embodiment. It should be the same material as.

Further, the sum of the elemental composition ratios of the group 13 elements (particularly gallium) and oxygen with respect to all the elements constituting the inorganic surface layer is 0.70 or more, for example, 15 such as N, P, As and the like. When group elements are mixed, the influence of these binding with group 13 elements (particularly gallium) is suppressed, and the composition of oxygen and group 13 elements (particularly gallium) that can improve the hardness and electrical characteristics of the inorganic surface layer. It becomes easier to find the appropriate range of ratio (oxygen / Group 13 element (especially gallium)). From the above viewpoint, the sum of the elemental composition ratios is preferably 0.75 or more, preferably 0.80 or more, and more preferably 0.85 or more.

The inorganic protective layer may contain hydrogen in addition to the above-mentioned inorganic material. Further, for control of the conductive type, for example, in the case of n type, one or more elements selected from C, Si, Ge and Sn may be contained. Further, for example, in the case of p-type, one or more elements selected from N, Be, Mg, Ca and Sr may be contained.

Here, when the inorganic protective layer is composed of, for example, gallium, oxygen, and hydrogen if necessary, it is excellent in mechanical strength, translucency, flexibility, and its conductivity controllability. , Suitable element composition ratios are as follows.
The elemental composition ratio of gallium is often 0.20 or more and 0.50 or less, preferably 0.25 or more and 0.40 or less, and more preferably 0. It is 30 or more and 0.40 or less.
The elemental composition ratio of oxygen is, for example, preferably 0.30 or more and 0.70 or less, preferably 0.30 or more and 0.60 or less, and more preferably 0. It is 35 or more and 0.55 or less.
The elemental composition ratio of hydrogen is often 0.10 or more and 0.40 or less, preferably 0.10 or more and 0.30 or less, and more preferably 0. It is 15 or more and 0.25 or less.

Here, the elemental composition ratio, atomic number ratio, etc. of each element in the inorganic protective layer are obtained by Rutherford backscattering (hereinafter referred to as "RBS") including the distribution in the thickness direction. In RBS, as an accelerator. NEC 3SDH Pelletron is used, CE & A RBS-400 is used as the end station, and 3S-R10 is used as the system. The HYPRA program of CE & A is used for the analysis.
The measurement conditions of RBS are that the He ++ ion beam energy is 2.275 eV, the detection angle is 160 °, and the Glazing Angle is about 109 ° with respect to the incident beam.

Specifically, the RBS measurement is performed as follows. First, the He ++ ion beam is incident perpendicular to the sample, the detector is set at 160 ° with respect to the ion beam, and the backscattered He signal. To measure. The composition ratio and film thickness are determined from the detected He energy and intensity. The spectrum may be measured at two detection angles in order to improve the accuracy of determining the composition ratio and the film thickness. Accuracy is improved by measuring and cross-checking at two detection angles with different depth direction resolution and backscattering mechanics.
The number of He atoms scattered backward by the target atom is determined only by three factors: 1) the atomic number of the target atom, 2) the energy of the He atom before scattering, and 3) the scattering angle. The density is assumed by calculation from the measured composition, and the thickness is calculated using this. The density error is within 20%.

The elemental composition ratio of hydrogen is determined by hydrogen forward scattering (hereinafter referred to as "HFS").
In the HFS measurement, NEC 3SDH Pelletron is used as an accelerator, CE & A RBS-400 is used as an end station, and 3S-R10 is used as a system. The HYPRA program of CE & A is used for the analysis. The measurement conditions for HFS are as follows.
-He ++ ion beam energy: 2.275 eV
-Detection angle: Grazing Angle 30 ° for an incident beam of 160 °

The HFS measurement picks up the signal of hydrogen scattered in front of the sample by setting the detector at 30 ° to the He ++ ion beam and the sample at 75 ° from the normal. At this time, it is preferable to cover the detector with aluminum foil to remove He atoms scattered together with hydrogen. Quantification is performed by normalizing the hydrogen counts of the reference sample and the sample under test by stopping power and then comparing them. As a reference sample, a sample in which H is ion-implanted into Si and muscovite are used.
Muscovite is known to have a hydrogen concentration of 6.5 atomic%.
The H adsorbed on the outermost surface is corrected, for example, by subtracting the amount of H adsorbed on the clean Si surface.

-Characteristics of inorganic protective layer-
As described above, the inorganic protective layer in the electrophotographic photosensitive member of the second embodiment has a first region and a volume resistivity having a volume resistivity of 2.0 × 10 ⁷ Ωcm or more and 1.0 × 10 ¹⁰ Ωcm or less. It has a second region with a ratio of 2.0 × 10 ¹⁰ Ωcm or more.
The volume resistivity in the first region is often 1.0 × 10 ⁸ Ωcm or more and 1.0 × 10 ¹⁰ Ωcm or less in terms of suppressing the increase in the residual potential while ensuring the sensitivity. It is preferably 0 × 10 ⁸ Ωcm or more and 5.0 × 10 ⁹ Ωcm or less. In the same respect, the volume resistivity of the second region is often 3.0 × 10 ¹⁰ Ωcm or more, and preferably 4.0 × 10 ¹⁰ Ωcm or more. The upper limit of the volume resistivity in the second region is not particularly limited, and examples thereof include 1.0 × 10 ¹¹ Ωcm or less.
Further, the volume resistivity in each region of the inorganic protective layer of the electrophotographic photosensitive member according to the first embodiment is within the range of the volume resistivity in each region of the inorganic protective layer of the electrophotographic photosensitive member according to the second embodiment. It is better to meet.

This volume resistivity is calculated from the resistance values measured under the conditions of a frequency of 1 kHz and a voltage of 1 V using an LCR meter ZM2371 manufactured by nF, based on the electrode area and the sample thickness.
The measurement sample is a sample obtained by forming a film on an aluminum substrate under the same conditions as when forming the inorganic protective layer to be measured, and forming a gold electrode on the film by vacuum vapor deposition. Alternatively, the sample may be a sample in which the inorganic protective layer is peeled off from the electrophotographic photosensitive member after production, partially etched, and sandwiched between a pair of electrodes.

The inorganic protective layer is preferably a non-single crystal film such as a microcrystalline film, a polycrystalline film, or an amorphous film. Among these, amorphous is particularly desirable in terms of surface smoothness, but polycrystalline film is more desirable in terms of hardness.
The growth cross section of the inorganic protective layer may have a columnar structure, but from the viewpoint of slipperiness, a structure with high flatness is desirable, and amorphous is desirable.
The crystallinity and amorphousness are determined by the presence or absence of points or lines in the diffraction image obtained by RHEED (reflection high-energy electron diffraction) measurement.

The elastic modulus of the entire inorganic protective layer is often 30 GPa or more and 80 GPa or less, preferably 40 GPa or more and 65 GPa or less.
When this elastic modulus is within the above range, the generation, peeling, and cracking of concave portions (dent-like scratches) of the inorganic protective layer are likely to be suppressed.
This elastic modulus is an average value obtained from the measured values of the indentation depth of 30 nm to 100 nm obtained by obtaining a depth profile by the continuous rigidity method (CSM) (US Pat. No. 4,48,141) using Nano Indenter SA2 manufactured by MTS Systems. Is used. The following are the measurement conditions.
-Measurement environment: 23 ° C, 55% RH
-Used indenter: Diamond regular triangular pyramid indenter (Berkovic indenter) Triangular pyramid indenter-Test mode: CSM mode The measurement sample is a sample formed on the substrate under the same conditions as when the inorganic protective layer to be measured was formed. It may be a sample obtained by peeling the inorganic protective layer from the prepared electrophotographic photosensitive member and partially etching the sample.

In the electrophotographic photosensitive member according to the present embodiment, the thickness of the first region is preferably thinner than the thickness of the second region in terms of suppressing an increase in the residual potential while ensuring sensitivity. In the same respect, the ratio of the ratio of the thickness of the second region to the thickness of the first region (thickness of the second region / thickness of the first region) is 3 or more and 100 or less (preferably, the thickness of the first region). It is preferably 10 or more and 100 or less, more preferably 10 or more and 30 or less).

Further, the thickness of the first region should be 0.01 μm or more and 0.5 μm or less (preferably 0.03 μm or more and 0.10 μm or less) in terms of suppressing an increase in the residual potential while ensuring sensitivity. Is good. In the same respect, the thickness of the second region is preferably 0.3 μm or more and 3.5 μm or less (preferably 0.4 μm or more and 0.10 μm or less).

Further, in the electrophotographic photosensitive member according to the present embodiment, the total film thickness of the inorganic protective layer is, for example, preferably more than 1.5 μm and 10 μm or less, preferably 3 μm or more and 10 μm or less, and 3 μm or more and 6 μm. The following is more preferable.
When the overall film thickness of the inorganic protective layer is within the above range, the occurrence of scratches on the inorganic protective layer is likely to be suppressed.

-Formation of inorganic protective layer-
For the formation of the inorganic protective layer, for example, known vapor deposition methods such as plasma CVD (Chemical Vapor Deposition) method, metalorganic vapor phase growth method, molecular beam epitaxy method, thin film deposition, and sputtering are used.

Hereinafter, the formation of the inorganic protective layer will be described with reference to specific examples while showing an example of the film forming apparatus in the drawings. The following description describes a method for forming an inorganic protective layer containing gallium, oxygen, and hydrogen, but the present invention is not limited to this, and a well-known forming method is used depending on the composition of the target inorganic protective layer. Should be applied.

FIG. 5 is a schematic schematic view showing an example of a film forming apparatus used for forming the inorganic protective layer of the electrophotographic photosensitive member according to the present embodiment, and FIG. 5A is a case where the film forming apparatus is viewed from the side. 5 (B) shows a schematic cross-sectional view between A1 and A2 of the film forming apparatus shown in FIG. 5 (A). In FIG. 5, 210 is a film forming chamber, 211 is an exhaust port, 212 is a base rotating part, 213 is a base support member, 214 is a base, 215 is a gas introduction pipe, and 216 is a gas introduced from a gas introduction pipe 215. A shower nozzle having an opening, 217 is a plasma diffusion section, 218 is a high frequency power supply section, 219 is a flat plate electrode, 220 is a gas introduction tube, and 221 is a high frequency discharge tube section.

In the film forming apparatus shown in FIG. 5, an exhaust port 211 connected to a vacuum exhaust device (not shown) is provided at one end of the film forming chamber 210, and the side where the exhaust port 211 of the film forming chamber 210 is provided. On the opposite side, a plasma generator including a high-frequency power supply unit 218, a flat plate electrode 219, and a high-frequency discharge tube unit 221 is provided.
This plasma generator is arranged inside a high-frequency discharge tube section 221 and a high-frequency discharge tube section 221 and has a flat plate electrode 219 having a discharge surface provided on the exhaust port 211 side and a flat plate outside the high-frequency discharge tube section 221. It is composed of a high frequency power supply unit 218 connected to a surface opposite to the discharge surface of the electrode 219. A gas introduction pipe 220 for supplying gas into the high frequency discharge pipe 221 is connected to the high frequency discharge pipe portion 221, and the other end of the gas introduction pipe 220 is a first not shown (not shown). It is connected to the gas source of.

The plasma generator shown in FIG. 6 may be used instead of the plasma generator provided in the film forming apparatus shown in FIG. FIG. 6 is a schematic schematic view showing another example of the plasma generator used in the film forming apparatus shown in FIG. 5, and is a side view of the plasma generator. In FIG. 6, 222 represents a high frequency coil, 223 represents a quartz tube, and 220 is the same as that shown in FIG. This plasma generator comprises a quartz tube 223 and a high frequency coil 222 provided along the outer peripheral surface of the quartz tube 223, and one end of the quartz tube 223 is a film forming chamber 210 (not shown in FIG. 6). Is connected to. Further, a gas introduction tube 220 for introducing gas into the quartz tube 223 is connected to the other end of the quartz tube 223.

In FIG. 5, a rod-shaped shower nozzle 216 extending along the discharge surface is connected to the discharge surface side of the flat plate electrode 219, and one end of the shower nozzle 216 is connected to the gas introduction pipe 215, and this gas is connected. The introduction pipe 215 is connected to a second gas supply source (not shown) provided outside the film forming chamber 210.
Further, a substrate rotating portion 212 is provided in the film forming chamber 210, and the substrate support member is provided so that the cylindrical substrate 214 faces the longitudinal direction of the shower nozzle 216 and the axial direction of the substrate 214. It can be attached to the substrate rotating portion 212 via the 213. During film formation, the substrate 214 rotates in the circumferential direction due to the rotation of the substrate rotating portion 212. As the substrate 214, for example, a photoconductor or the like laminated up to an organic photosensitive layer in advance is used.

The formation of the inorganic protective layer is carried out, for example, as follows.
First, oxygen gas (or helium (He) diluted oxygen gas), helium (He) gas, and, if necessary, hydrogen (H2) gas are introduced from the gas introduction tube 220 into the high-frequency discharge tube section 221 and at high frequencies. A 13.56 MHz radio wave is supplied from the power supply unit 218 to the flat plate electrode 219. At this time, the plasma diffusion portion 217 is formed so as to radiate from the discharge surface side of the flat plate electrode 219 to the exhaust port 211 side. Here, the gas introduced from the gas introduction pipe 220 flows through the film forming chamber 210 from the flat plate electrode 219 side to the exhaust port 211 side. The flat plate electrode 219 may be a flat plate electrode 219 in which the electrode is surrounded by an earth shield.

Next, by introducing trimethylgallium gas into the film forming chamber 210 via the gas introduction tube 215 and the shower nozzle 216 located on the downstream side of the flat plate electrode 219 which is the activating means, gallium and oxygen are added to the surface of the substrate 214. A non-single crystal film containing hydrogen is formed.
As the substrate 214, for example, a substrate on which an organic photosensitive layer is formed is used.

Since an organic photosensitive member having an organic photosensitive layer is used, the temperature of the surface of the substrate 214 at the time of forming the inorganic protective layer is preferably 150 ° C. or lower, more preferably 100 ° C. or lower, and particularly preferably 30 ° C. or higher and 100 ° C. or lower.
Even if the temperature of the surface of the substrate 214 is 150 ° C or lower at the beginning of film formation, if the temperature rises above 150 ° C due to the influence of plasma, the organic photosensitive layer may be damaged by heat, so this effect should be taken into consideration. It is desirable to control the surface temperature of the substrate 214.
The temperature of the surface of the substrate 214 may be controlled by a heating means, a cooling means (not shown in the figure), or the like, or may be left to the natural temperature rise at the time of discharge. When heating the substrate 214, the heater may be installed on the outside or the inside of the substrate 214. When cooling the substrate 214, a cooling gas or liquid may be circulated inside the substrate 214.
When it is desired to avoid an increase in the temperature of the surface of the substrate 214 due to electric discharge, it is effective to adjust the high-energy gas flow that hits the surface of the substrate 214. In this case, conditions such as gas flow rate, discharge output, and pressure are adjusted so as to reach the required temperature.

Further, instead of trimethylgallium gas, an organometallic compound containing aluminum or a hydride such as diborane can be used, and two or more of these may be mixed.
For example, in the initial stage of forming the inorganic protective layer, trimethylindium is introduced into the film forming chamber 210 via the gas introduction tube 215 and the shower nozzle 216 to form a film containing nitrogen and indium on the substrate 214. Then, this film absorbs the ultraviolet rays generated when the film is continuously formed and deteriorates the organic photosensitive layer. Therefore, damage to the organic photosensitive layer due to the generation of ultraviolet rays during film formation is suppressed.

As a method for doping the dopant at the time of film formation, SiH3 and SnH4 are used for the n-type, and biscyclopentadienylmagnesium, dimethylcalcium, dimethylstrontium, etc. are used for the p-type in a gas state. .. Further, in order to dope the dopant element into the surface layer, a known method such as a heat diffusion method or an ion implantation method may be adopted.
Specifically, for example, by introducing a gas containing at least one dopant element into the film forming chamber 210 via the gas introduction pipe 215 and the shower nozzle 216, a conductive type such as n-type or p-type can be obtained. Obtain an inorganic protective layer.

In the film forming apparatus described with reference to FIGS. 5 and 6, the active nitrogen or active hydrogen formed by the discharge energy may be independently controlled by providing a plurality of active apparatus, or with a nitrogen atom such as _NH3 . A gas containing hydrogen atoms at the same time may be used. Further H ₂ may be added. Further, the condition that active hydrogen is freely generated from the organometallic compound may be used.
By doing so, activated carbon atoms, gallium atoms, nitrogen atoms, hydrogen atoms, etc. are present on the surface of the substrate 214 in a controlled state. Then, the activated hydrogen atom has an effect of desorbing hydrogen of a hydrocarbon group such as a methyl group or an ethyl group constituting an organic metal compound as a molecule.
Therefore, a hard film (inorganic protective layer) constituting a three-dimensional bond is formed.

The plasma generating means of the film forming apparatus shown in FIGS. 5 and 6 uses a high frequency oscillator, but is not limited to this, and for example, a microwave oscillator may be used or an electrocyclotron resonance method may be used. Or a helicon plasma type device may be used. Further, in the case of a high frequency oscillator, it may be an inductive type or a capacitive type.
Further, two or more of these devices may be used in combination, or two or more of the same type of devices may be used. A high-frequency oscillator is desirable in order to suppress the temperature rise on the surface of the substrate 214 due to plasma irradiation, but a device that suppresses heat irradiation may be provided.

When two or more different types of plasma generators (plasma generating means) are used, it is desirable that discharges occur simultaneously at the same pressure. Further, a pressure difference may be provided between the region where the discharge is performed and the region where the film is formed (the portion where the substrate is installed). These devices may be arranged in series with respect to the gas flow formed in the film forming apparatus from the portion where the gas is introduced to the portion where the gas is discharged, or both devices may be arranged on the film forming surface of the substrate. They may be arranged so as to face each other.

For example, when two types of plasma generating means are installed in series with respect to a gas flow, taking the film forming apparatus shown in FIG. 5 as an example, the shower nozzle 216 is used as an electrode to cause a discharge in the film forming chamber 210. It is used as a plasma generator of 2. In this case, for example, a high frequency voltage is applied to the shower nozzle 216 via the gas introduction pipe 215 to cause a discharge in the film forming chamber 210 using the shower nozzle 216 as an electrode. Alternatively, instead of using the shower nozzle 216 as an electrode, a cylindrical electrode is provided between the substrate 214 and the flat plate electrode 219 in the film forming chamber 210, and the cylindrical electrode is used to use the film forming chamber 210. Causes an electric discharge inside.
Further, when two different types of plasma generators are used under the same pressure, for example, when a microwave oscillator and a high frequency oscillator are used, the excitation energy of the excited species can be significantly changed, and the film quality can be controlled. It is valid. Further, the discharge may be performed in the vicinity of atmospheric pressure (70,000 Pa or more and 110,000 Pa or less). When discharging in the vicinity of atmospheric pressure, it is desirable to use He as the carrier gas.

To form the inorganic protective layer, for example, a substrate 214 having an organic photosensitive layer formed on the substrate is placed in a film forming chamber 210, and a mixed gas having a different composition is introduced to form the inorganic protective layer.

Further, as the film forming condition, for example, in the case of discharging by high frequency discharge, it is desirable that the frequency is in the range of 10 kHz or more and 50 MHz or less in order to perform high quality film forming at a low temperature. Although the output depends on the size of the substrate 214, it is desirable that the output is in the range of 0.01 W / cm ² or more and 0.2 W / cm ² or less with respect to the surface area of the substrate. The rotation speed of the substrate 214 is preferably in the range of 0.1 rpm or more and 500 rpm or less.

The elemental composition ratio (oxygen / Group 13 element) and volume resistivity of the first region and the second region of the inorganic protective layer are adjusted by, for example, controlling the pressure and high frequency power of the plasma generator. To. It is also adjusted by the flow rate ratio of trimethylgallium, helium-diluted oxygen, and hydrogen supplied to the plasma generator. Specifically, it is adjusted by the flow rate ratio of oxygen diluted with trimethylgallium and helium. For the thickness of each of the first region and the second region, trimethylgallium and helium-diluted oxygen supplied to the plasma generator are adjusted by the supply time.

The example of the electrophotographic photosensitive member in which the organic photosensitive layer is a function-separated type and the charge transport layer is a single-layer type has been described above. However, the electrophotographic photosensitive member shown in FIG. When the transport layer is a multi-layer type), the charge transport layer 3A in contact with the inorganic protective layer 5 has the same configuration as the charge transport layer 3 of the electrophotographic photosensitive member shown in FIG. 1, while is in contact with the inorganic protective layer 5. The charge transport layer 3B that does not have a charge transport layer 3B may have the same configuration as a well-known charge transport layer.
However, the film thickness of the charge transport layer 3A is preferably 1 μm or more and 15 μm or less. The film thickness of the charge transport layer 3B is preferably 15 μm or more and 29 μm or less.

On the other hand, in the case of the electrophotographic photosensitive member shown in FIG. 3 (an example in which the organic photosensitive layer is a single layer type), the single layer type organic photosensitive layer 6 (charge generation / charge transport layer) is a charge transport layer of the electrophotographic photosensitive member. It is preferable to have the same configuration except that 3 and the charge generating material are included.
However, the content of the charge generating material in the single-layer type organic photosensitive layer 6 is 0.1% by mass or more and 10% by mass or less (preferably 0.8% by mass or more 5) with respect to the entire single-layer type organic photosensitive layer. It is better to set it to mass% or less). The content of the charge transport material is preferably 5% by mass or more and 50% by mass or less with respect to the total solid content.
The film thickness of the single-layer organic photosensitive layer 6 is preferably 15 μm or more and 30 μm or less.

The single-layer organic photosensitive layer 6 is not limited to the above, and may be an amorphous silicon photosensitive layer formed of a material containing amorphous silicon. The amorphous silicon type photosensitive layer may be formed, for example, by containing amorphous silicon and impurities (dopants) such as boron. The amorphous silicon photosensitive layer is formed by a chemical vapor phase method or the like.

Further, the inorganic protective layer may be formed by repeatedly laminating the combination of the above-mentioned first region and the second region on the photosensitive layer in this order.
For example, in the electrophotographic photosensitive member shown in FIG. 4, the inorganic protective layer is an example in which the combination of the first region and the second region is repeatedly laminated in this order, and the number of repetitions is three. Is shown. The number of repetitions is a combination of the first region and the second region laminated in this order from the photosensitive layer side as one unit, and represents the number of times this unit is repeated. The number of repeated stacking of the combination of the first region and the second region may be, for example, two times. The number of repetitions of the first region and the second region is preferably 1 or more and 10 or less in order to further suppress the increase in the residual potential while ensuring the sensitivity. The number of repetitions may be 3 or more, 4 or more, or 5 or more. Further, it may be 9 times or less, or 8 times or less.

Further, in the formation of the inorganic protective layer, each layer may be continuously formed by introducing a mixed gas having a different composition depending on the target element composition ratio or volume resistivity, or separately. You may go independently. Further, for each layer, the film forming conditions may be selected according to the target element composition ratio or volume resistivity.

[Image forming device (and process cartridge)]
The image forming apparatus according to the present embodiment includes an electrophotographic photosensitive member, a charging means for charging the surface of the electrophotographic photosensitive member, and an electrostatic latent image forming on the surface of the charged electrophotographic photosensitive member. Means, a developing means for developing an electrostatic latent image formed on the surface of an electrophotographic photosensitive member with a developer containing toner to form a toner image, and a transfer means for transferring the toner image to the surface of a recording medium. To be equipped with. Then, as the electrophotographic photosensitive member, the electrophotographic photosensitive member according to the present embodiment is applied.

The image forming apparatus according to the present embodiment is an apparatus provided with a fixing means for fixing the toner image transferred to the surface of the recording medium; direct transfer to directly transfer the toner image formed on the surface of the electrophotographic photosensitive member to the recording medium. Device of the method; Intermediate transfer in which the toner image formed on the surface of the electrophotographic photosensitive member is primarily transferred to the surface of the intermediate transfer body, and the toner image transferred to the surface of the intermediate transfer body is secondarily transferred to the surface of the recording medium. Device of the method; A device equipped with a cleaning means for cleaning the surface of the electrophotographic photosensitive member after the transfer of the toner image and before charging; the surface of the electrophotographic photosensitive member is irradiated with xerographic light after the transfer of the toner image and before charging. A device provided with a static elimination means for eliminating static electricity; a well-known image forming apparatus such as a device provided with an electrophotographic photosensitive member heating member for increasing the temperature of the electrophotographic photosensitive member and reducing the relative temperature is applied.

In the case of an intermediate transfer type apparatus, the transfer means is, for example, a primary transfer body in which a toner image is transferred to the surface and a primary transfer of a toner image formed on the surface of an electrophotographic photosensitive member to the surface of the intermediate transfer body. A configuration comprising a transfer means and a secondary transfer means for secondary transfer of the toner image transferred to the surface of the intermediate transfer body to the surface of the recording medium is applied.

The image forming apparatus according to the present embodiment may be either a dry developing type image forming apparatus or a wet developing method (development method using a liquid developer) image forming apparatus.

In the image forming apparatus according to the present embodiment, for example, the portion provided with the electrophotographic photosensitive member may have a cartridge structure (process cartridge) attached to and detached from the image forming apparatus. As the process cartridge, for example, a process cartridge including the electrophotographic photosensitive member according to the present embodiment is preferably used. In addition to the electrophotographic photosensitive member, the process cartridge may include at least one selected from the group consisting of, for example, a charging means, an electrostatic latent image forming means, a developing means, and a transfer means.

Hereinafter, an example of the image forming apparatus according to the present embodiment will be shown, but the present invention is not limited thereto. The main parts shown in the figure will be described, and the description thereof will be omitted for the others.

FIG. 7 is a schematic configuration diagram showing an example of an image forming apparatus according to the present embodiment.
As shown in FIG. 7, the image forming apparatus 100 according to the present embodiment includes a process cartridge 300 including an electrophotographic photosensitive member 7, an exposure apparatus 9 (an example of an electrostatic latent image forming means), and a transfer apparatus 40 (primary). A transfer device) and an intermediate transfer body 50 are provided. In the image forming apparatus 100, the exposure apparatus 9 is arranged at a position where the electrophotographic photosensitive member 7 can be exposed to the electrophotographic photosensitive member 7 from the opening of the process cartridge 300, and the transfer apparatus 40 is arranged via the intermediate transfer body 50. The intermediate transfer body 50 is arranged at a position facing the seventh, and a part of the intermediate transfer body 50 is arranged in contact with the electrophotographic photosensitive member 7. Although not shown, it also has a secondary transfer device that transfers the toner image transferred to the intermediate transfer body 50 to a recording medium (for example, paper). The intermediate transfer body 50, the transfer device 40 (primary transfer device), and the secondary transfer device (not shown) correspond to an example of the transfer means. In the image forming apparatus 100, the control device 60 (an example of the control means) is an apparatus for controlling the operation of each apparatus and each member in the image forming apparatus 100, and is arranged so as to be connected to each apparatus and each member. ing.

The process cartridge 300 in FIG. 7 has an electrophotographic photosensitive member 7, a charging device 8 (an example of a charging means), a developing device 11 (an example of a developing means), and a cleaning device 13 (an example of a cleaning means) integrated in a housing. I support it. The cleaning device 13 has a cleaning blade (an example of a cleaning member) 131, and the cleaning blade 131 is arranged so as to come into contact with the surface of the electrophotographic photosensitive member 7. The cleaning member may be a conductive or insulating fibrous member instead of the mode of the cleaning blade 131, and may be used alone or in combination with the cleaning blade 131.

In addition, in FIG. 7, as an image forming apparatus, a fibrous member 132 (roll shape) that supplies a lubricant 14 to the surface of an electrophotographic photosensitive member 7 and a fibrous member 133 (flat brush shape) that assists cleaning are shown. Examples are shown, but these are arranged as needed.

Hereinafter, each configuration of the image forming apparatus according to the present embodiment will be described.

-Charging device-
As the charging device 8, for example, a contact-type charging device using a conductive or semi-conductive charging roller, a charging brush, a charging film, a charging rubber blade, a charging tube, or the like is used. Further, a non-contact roller charger, a scorotron charger using corona discharge, a corotron charger, or the like, which is known per se, is also used.

-Exposure device-
Examples of the exposure device 9 include an optical system device that exposes light such as a semiconductor laser beam, an LED light, and a liquid crystal shutter light on the surface of the electrophotographic photosensitive member 7 in a predetermined image pattern. The wavelength of the light source is within the spectral sensitivity region of the electrophotographic photosensitive member. The mainstream wavelength of a semiconductor laser is near infrared, which has an oscillation wavelength in the vicinity of 780 nm. However, the wavelength is not limited to this, and a laser having an oscillation wavelength in the 600 nm range or a laser having an oscillation wavelength of 400 nm or more and 450 nm or less may be used as a blue laser. Further, a surface-emitting laser light source of a type capable of outputting a multi-beam is also effective for forming a color image.

-Developer-
Examples of the developing device 11 include a general developing device that develops by contacting or non-contacting a developer. The developing device 11 is not particularly limited as long as it has the above-mentioned functions, and is selected according to the purpose. For example, a known developer having a function of adhering a one-component developer or a two-component developer to the electrophotographic photosensitive member 7 using a brush, a roller, or the like can be mentioned. Of these, those using a developing roller in which the developing agent is held on the surface are preferable.

The developing agent used in the developing apparatus 11 may be a one-component developing agent containing only toner or a two-component developing agent containing a toner and a carrier. Further, the developer may be magnetic or non-magnetic. Well-known developeres are applied.

-Cleaning device-
As the cleaning device 13, a cleaning blade type device including a cleaning blade 131 is used.
In addition to the cleaning blade method, a fur brush cleaning method and a simultaneous development cleaning method may be adopted.

-Transfer device-
As the transfer device 40, for example, a contact type transfer charger using a belt, a roller, a film, a rubber blade, or the like, a scorotron transfer charger using corona discharge, a transfer charger known per se, such as a corotron transfer charger, can be used. Can be mentioned.

-Intermediate transcript-
As the intermediate transfer body 50, a belt-shaped material (intermediate transfer belt) containing semi-conductive polyimide, polyamide-imide, polycarbonate, polyarylate, polyester, rubber, or the like is used. Further, as the form of the intermediate transfer body, a drum-shaped one may be used in addition to the belt-shaped one.

-Control device-
The control device 60 is configured as a computer that controls the entire device and performs various operations. Specifically, the control device 60 is, for example, a CPU (Central Processing Unit; Central Processing Unit), a ROM (Read Only Memory) that stores various programs, and a RAM (Random Access Memory) that is used as a work area when the programs are executed. ), A non-volatile memory for storing various information, and an input / output interface (I / O). Each of the CPU, ROM, RAM, non-volatile memory, and I / O is connected via a bus. Each part of the image forming apparatus 100 such as the electrophotographic photosensitive member 7 (including the drive motor 30), the charging device 8, the exposure device 9, the developing device 11, and the transfer device 40 is connected to the I / O.

The CPU executes, for example, a control program of a program (for example, an image forming sequence, a recovery sequence, etc.) stored in a ROM or a non-volatile memory, and controls the operation of each part of the image forming apparatus 100. RAM is used as working memory. In the ROM or the non-volatile memory, for example, a program executed by the CPU, data necessary for processing by the CPU, and the like are stored. The control program and various data may be stored in another storage device such as a storage unit, or may be acquired from the outside via the communication unit.

Further, various drives may be connected to the control device 60. As various drives, data can be read from a computer-readable portable recording medium such as a flexible disk, a magneto-optical disk, a CD-ROM, a DVD-ROM, or a USB (Universal Serial Bus) memory, or data can be read from the recording medium. There is a device that writes data. When various drives are provided, the control program may be recorded on a portable recording medium, and the control program may be read and executed by the corresponding drive.

FIG. 8 is a schematic configuration diagram showing another example of the image forming apparatus according to the present embodiment.
The image forming apparatus 120 shown in FIG. 8 is a tandem type multicolor image forming apparatus equipped with four process cartridges 300. In the image forming apparatus 120, four process cartridges 300 are arranged in parallel on the intermediate transfer body 50, and one electrophotographic photosensitive member is used for each color. The image forming apparatus 120 has the same configuration as the image forming apparatus 100 except that it is a tandem type.

The image forming apparatus 100 according to the present embodiment is not limited to the above configuration, and is, for example, a cleaning apparatus around the electrophotographic photosensitive member 7 on the downstream side in the rotation direction of the electrophotographic photosensitive member 7 with respect to the transfer device 40. A first static eliminator for aligning the polarities of the remaining toner and facilitating removal with a cleaning brush may be provided on the upstream side of the electrophotographic photosensitive member in the rotation direction rather than the cleaning device 13. Also, a second static eliminator for eliminating static electricity on the surface of the electrophotographic photosensitive member 7 may be provided on the downstream side in the rotation direction of the electrophotographic photosensitive member and on the upstream side in the rotation direction of the electrophotographic photosensitive member than the charging device 8. ..

Further, the image forming apparatus 100 according to the present embodiment is not limited to the above configuration, and is a well-known configuration, for example, a direct transfer type image forming apparatus that directly transfers a toner image formed on the electrophotographic photosensitive member 7 to a recording medium. It may be adopted.

Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples. In the following examples, "parts" means parts by mass.

[Preparation and preparation of silica particles]
-Silica particles-
Untreated (hydrophilic) silica particles "trade name: OX50 (manufactured by Aerosil)" in 100 parts by mass as a hydrophobizing agent 1,1,1,3,3,3-hexamethyldisilazane (Tokyo Chemical Industry Co., Ltd.) (Manufactured by) 30 parts by mass was added and reacted for 24 hours, and then the silica particles were collected by filtration to obtain hydrophobized silica particles. The condensation rate of these silica particles was 93%. The silica particles have a trimethylsilyl group on the surface. The volume average particle size of the silica particles is 40 nm.

<Example 1>
-Preparation of undercoat layer-
Zinc oxide (average particle diameter 70 nm: manufactured by Teika Co., Ltd .: specific surface area value 15 m ² / g) 100 parts by mass is stirred and mixed with 500 parts by mass of tetrahydrofuran, and a silane coupling agent (KBM503: manufactured by Shin-Etsu Chemical Co., Ltd.) 1.3 mass. The portion was added and stirred for 2 hours. Then, tetrahydrofuran was distilled off under reduced pressure and baked at 120 ° C. for 3 hours to obtain zinc oxide surface-treated with a silane coupling agent.
110 parts by mass of the surface-treated zinc oxide is stirred and mixed with 500 parts by mass of tetrahydrofuran, a solution in which 0.6 parts by mass of Arizarin is dissolved in 50 parts by mass of tetrahydrofuran is added, and the mixture is stirred at 50 ° C. for 5 hours. bottom. Then, zinc oxide to which alizarin was added was filtered off by vacuum filtration, and further dried under reduced pressure at 60 ° C. to obtain zinc oxide to which alizarin was added.
60 parts by mass of this zinc oxide imparted with alizarin, 13.5 parts by mass of a curing agent (blocked isocyanate Sumijoule 3175, manufactured by Sumitomo Bavarian Urethane Co., Ltd.), and 15 parts by mass of butyral resin (Eslek BM-1, manufactured by Sekisui Chemical Co., Ltd.). Was mixed with 85 parts by mass of methyl ethyl ketone to obtain a mixed solution. 38 parts by mass of this mixed solution and 25 parts by mass of methyl ethyl ketone were mixed and dispersed with a sand mill using 1 mmφ glass beads for 2 hours to obtain a dispersion solution.
Dioctyltin dilaurate: 0.005 parts by mass and 40 parts by mass of silicone resin particles (Tospearl 145, manufactured by Momentive Performance Materials) were added to the obtained dispersion as a catalyst to obtain a coating liquid for forming an undercoat layer. rice field. This coating liquid is applied to an aluminum substrate having an outer diameter of 30 mm, a length of 365 mm, and a thickness (thickness) of 1.0 mm by a dip coating method, dried and cured at 170 ° C. for 40 minutes, and then an undercoat layer having a thickness of 19 μm. Got

-Preparation of charge transport layer-
Silica particles (1) 250 parts by mass of tetrahydrofuran is placed in 65 parts by mass, and 4- (2,2-diphenylethyl) -4', 4''-dimethyl-triphenylamine 25 parts by mass is maintained at a liquid temperature of 20 ° C. 25 parts by mass of a bisphenol Z-type polycarbonate resin (viscosity average molecular weight: 30,000) was added as a binder resin, and the mixture was stirred and mixed for 12 hours to obtain a coating liquid for forming a charge transport layer. This coating liquid for forming a charge transport layer was applied onto the undercoat layer and dried at 135 ° C. for 40 minutes to form a charge transport layer having a film thickness of 30 μm.

-Preparation of charge generation layer-
Positions where the Bragg angle (2θ ± 0.2 °) of the X-ray diffraction spectrum using Cukα characteristic X-ray as a charge generating substance is at least 7.3 °, 16.0 °, 24.9 °, 28.0 ° A mixture consisting of 15 parts by mass of hydroxygallium phthalocyanine having a diffraction peak, 10 parts by mass of a vinyl chloride / vinyl acetate copolymer (VMCH, manufactured by Nippon Unicar Co., Ltd.) as a binder resin, and 200 parts by mass of n-butyl acetate in diameter. The mixture was dispersed in a sand mill for 4 hours using 1 mmφ glass beads. 175 parts by mass of n-butyl acetate and 180 parts by mass of methyl ethyl ketone were added to the obtained dispersion and stirred to obtain a coating liquid for forming a charge generation layer.

This coating liquid for forming a charge generation layer was immersed and coated on the charge transport layer and dried at room temperature (25 ° C.) to form a charge generation layer having a film thickness of 0.2 μm.

Through the above steps, an organic photoconductor (1) was obtained by laminating and forming an undercoat layer, a charge transport layer, and a charge generation layer on an aluminum substrate in this order.

-Formation of inorganic protective layer-
First, Table 1 shows the conditions for forming the inorganic protective layer.
The following film forming apparatus was used to form the inorganic protective layer.
・ Method: Plasma CVD, capacitive coupling type, high frequency power supply frequency 13.56MHz, magnetic fluid type for substrate rotation, rotation introduction machine installed ・ Vacuum chamber shape: Cylindrical type, diameter 165mm x length 1050mm
-Discharge electrode: Dimensions 770 mm x 85 mm, distance between the discharge electrode and the base material 40 mm
・ Arrangement method of photoconductors: Two organic photoconductors are arranged coaxially in the vacuum chamber length direction. ・ Gas flow rate is set by a mass flow controller. ・ Vacuum exhaust by a rotary pump and a mechanical booster pump. ・ Vacuum reached before film formation: 1.0 × 10 ^-2 Pa
In Table 1, O ₂ gas is He diluted 40% oxygen gas, H ₂ gas is 100% hydrogen gas, TMG gas is 100% trimethyl gallium gas, and He gas is 100% helium gas.

In addition, each characteristic in Table 1 was measured as follows.
A sample film formed on a silicon substrate having an atomic number ratio of 0.5 mm so as to have a thickness of 1.0 μm was evaluated by EDS (Energy Dispersive X-ray Analyzer) and the method described above.
Spectral transmittance: A sample film formed on a quartz substrate having a thickness of 1.0 mm so as to have a thickness of 1.0 μm was evaluated with an ultraviolet-visible spectrophotometer to evaluate the light transmittance in the wavelength range of 300 nm to 800 nm.
Volume resistivity: A gold electrode having a diameter of 2 mm was formed on a sample film formed on an aluminum substrate having a thickness of 1.0 mm so as to have a thickness of 1.0 μm by a DC sputtering method, and evaluated.

(Formation of the first region)
The organic photoconductor (1) produced above was placed on a substrate support member in the film forming chamber of the film forming apparatus, and the film forming chamber was evacuated through the exhaust port until the pressure reached 0.01 Pa. This vacuum exhaust was performed within 5 minutes after the completion of the replacement of the high-concentration oxygen-containing gas.
Next, as shown in Table 2, a film was formed under the film forming conditions of Condition 4. That is, He-diluted 40% oxygen gas (6 sccm) and H ₂ gas (500 sccm) are introduced from the gas introduction tube into the high-frequency discharge tube section provided with a flat plate electrode having a diameter of 85 mm, and the high-frequency power supply section and the matching circuit are used. A 13.56 MHz radio wave was set at an output of 500 W, matched with a tuner, and discharged from a flat plate electrode. The reflected wave at this time was 0 W.
Next, trimethylgallium gas (7.5 sccm) was introduced from the shower nozzle to the plasma diffusion portion in the film forming chamber via the gas introduction tube. At this time, the reaction pressure in the film forming chamber measured by the Baratron vacuum gauge was 25 Pa.
In this state, the organic photoconductor (1) is formed into a film for 37 minutes while rotating at a speed of 500 rpm, and the first region of the inorganic protective layer is formed on the surface of the charge transport layer of the organic photoconductor (1) to have a film thickness of 0. It was formed at .50 μm.

(Formation of the second region)
Next, high-frequency discharge was stopped, changed to He-diluted 40% oxygen gas (13 sccm), H ₂ gas (500 sccm) and trimethylgallium gas (10 sccm), and then high-frequency discharge was started again.
In this state, the organic photoconductor (1) having the first region formed was formed into a film for 189 minutes while rotating at a speed of 500 rpm, and a second region having a thickness of 3.5 μm was formed on the first region. ..

According to the above operation procedure, an inorganic protective layer having an overall thickness of 4.0 μm, in which the number of repetitions between the first region and the second region is one and the second region is the outermost layer, is formed. Formed. The time required to form the entire inorganic protective layer was 226 minutes.

Through the above steps, the undercoat layer, the charge generation layer, the charge transport layer, and the inorganic protective layer (first region + second region) are sequentially formed on the conductive substrate, and the electrograph of Example 1 is formed. A photoconductor was obtained.

<Examples 2 to 15 Comparative Examples 1 to 12>
According to Tables 2 and 3, the elemental composition ratio in the first region and the second region of the inorganic protective layer, the volume resistivity, the number of repetitions of the first region and the second region, and the total thickness of the inorganic protective layer. The same as in Example 1 except that the (thickness), the thickness of each region of the first region and the second region, the amount of silica particles in the charge transport layer, and the thickness (thickness) of the conductive substrate were changed. The electrophotographic photosensitive members of each example were obtained. The composition of the charge transport layer was adjusted so that the mass% of the silica particles was the value shown in Table 1 as the amount with respect to the entire charge transport layer.

(evaluation)
-Evaluation of photoconductor sensitivity and residual potential-
The sensitivity and residual potential of each example were evaluated using a universal scanner capable of setting a predetermined charging potential and exposure amount.
-Evaluation of sensitivity: It was evaluated as a half exposure amount when charged to -700 V. After charging to -700V, the surface potential of the photoconductor immediately after charging is halved (-350V) by light irradiation (light source: semiconductor laser, wavelength 780 nm, output 5 mW) (mJ / m ² ). ) Was measured.
-Evaluation of residual potential: The potential (V) on the surface of the photoconductor after light attenuation was measured.

-Evaluation of dents and scratches on the photoconductor-
The photoconductors obtained in each example were attached to an image forming apparatus obtained by modifying the Fuji Xerox multifunction device DocuCenter V 7775 for a positively charged electrophotographic photosensitive member to continuously form 10 images, and this was repeated. A total of 10,000 images were formed. Then, the surface of the photoconductor was observed with an optical microscope (visual field size 500 μm × 500 μm), the number of dents and scratches was counted, and the evaluation was made according to the following evaluation criteria. The dents (dents) and scratches were judged as follows.
・ Shape of dent: Elliptical shape with maximum diameter of 50 μm or less and aspect ratio of 0.8 to 1.2 ・ Shape of scratch: width of 50 μm or less and length of 0.1 mm to 3 mm in the circumferential direction of the photoconductor Streak shape-Dent evaluation criteria-
A (◎): No dents were observed in 10 visual fields (0)
B (○): 1 dent when observing 10 visual fields C (Δ): 2 or more dents when observing 10 visual fields, and 4 or less dents when observing 1 visual field D (×): 10 visual fields Two or more dents in observation and five or more dents in one field of view-Scratch evaluation criteria-
A (◎): No scratches were observed in 20 fields of view (0)
B (○): No scratches were observed when observing 10 visual fields (0), and 1 scratch was observed when observing 20 visual fields C (Δ): 1 scratch was observed when observing 10 visual fields D (×): Two or more scratches when observing 10 fields of view

The conditions shown in the film forming conditions column in Tables 2 and 3 are the same as the film forming conditions shown in Table 1. Further, [Ga] + [O] in Tables 2 and 3 represent the sum of the elemental composition ratios of gallium and oxygen with respect to all the elements constituting the inorganic protective layer.

From the above results, it can be seen that in this example, the sensitivity is secured and the increase in the residual potential is suppressed as compared with the comparative example.

1 Undercoat layer, 2 Charge generation layer, 3, 3A, 3B Charge transport layer, 4 Conductive substrate, 5, 5A, 5B, 5C Inorganic protective layer, 7, 7A, 7B, 7C, 7D electrophotographic photosensitive member, 8 Charging device, 9 exposure device, 11 developing device, 13 cleaning device, 14 lubricant, 30 drive motor, 40 transfer device, 50 intermediate transfer device, 60 control device, 100 image forming device, 120 image forming device, 131 cleaning blade, 132 Fibrous member (roll), 133 Fibrous member (flat brush), 300 process cartridge, 210 film forming chamber, 211 exhaust port, 212 substrate rotating part, 213 substrate support member, 214 substrate, 215, 220 gas introduction Tube, 216 Shower nozzle, 217 Plasma diffuser, 218 High frequency power supply, 219 Flat plate electrode, 221 High frequency discharge tube, 222 High frequency coil, 223 Quartz tube,

Claims (13)

With a conductive substrate,
The organic photosensitive layer provided on the conductive substrate and
The elemental composition ratio of the 13th group element and the oxygen to all the elements which are the inorganic protective layer provided on the organic photosensitive layer and contain the 13th group element and oxygen and constitute the inorganic protective layer. The first region in which the sum of the above is 0.70 or more and the element composition ratio (oxygen / Group 13 element) of the oxygen and the group 13 element is 1.10 or more and 1.30 or less, and A second region in which the elemental composition ratio (oxygen / Group 13 element) of the oxygen and the Group 13 element is 1.40 or more and 1.50 or less is provided on the organic photosensitive layer in this order. The second region is the top layer, the inorganic protective layer,
Equipped with
The Group 13 element is gallium.
A positively charged electrophotographic photosensitive member having an overall thickness of 3 μm or more and 10 μm or less of the inorganic protective layer . The volume resistivity of the first region is 2.0 × 10 ⁷ Ωcm or more and 1.0 × 10 ¹⁰ Ωcm or less, and the volume resistivity of the second region is 2.0 × 10 ¹⁰ Ωcm or more. The positively charged electrophotographic photosensitive member according to claim 1 . The positively charged electrophotographic photosensitive member according to claim 1 or 2 , wherein the thickness of the first region is thinner than the thickness of the second region. The positively charged electrograph according to claim 3 , wherein the ratio of the thickness of the second region to the thickness of the first region (thickness of the second region / thickness of the first region) is 3 or more and 100 or less. Photoreceptor. The positive according to claim 3 or 4 , wherein the thickness of the first region is 0.01 μm or more and 0.5 μm or less, and the thickness of the second region is 0.3 μm or more and 3.5 μm or less. Charged electrophotographic photosensitive member. The positively charged electrophotographic photosensitive member according to claim 1 , wherein the total thickness of the inorganic protective layer is 3 μm or more and 6 μm or less. The positively charged type according to any one of claims 1 to 6 , wherein the first region and the second region are repeatedly laminated in the order of the first region and the second region. Electrophotographic photosensitive member. The positively charged electrophotographic photosensitive member according to claim 7 , wherein the number of repetitions repeated in the order of the first region and the second region is 1 or more and 10 times or less. The positively charged electrophotographic photosensitive member according to any one of claims 1 to 8 , wherein the organic photosensitive layer has a layer containing a charge transport material, a binder resin, and silica particles. The positively charged electrophotographic photosensitive member according to claim 9 , wherein the content of the silica particles is 40% by mass or more and 80% by mass or less with respect to the entire layer containing the charge transport material and the binder resin. The positively charged electrophotographic photosensitive member according to any one of claims 1 to 10 , wherein the conductive substrate has a thickness of 1.5 mm or more. The positively charged electrophotographic photosensitive member according to any one of claims 1 to 11 is provided.
A process cartridge that can be attached to and detached from the image forming device. The positively charged electrophotographic photosensitive member according to any one of claims 1 to 11 .
A charging means for charging the surface of the positively charged electrophotographic photosensitive member,
An electrostatic latent image forming means for forming an electrostatic latent image on the surface of the charged positively charged electrophotographic photosensitive member,
A developing means for developing an electrostatic latent image formed on the surface of the positively charged electrophotographic photosensitive member with a developer containing toner to form a toner image, and a developing means.
A transfer means for transferring the toner image to the surface of a recording medium,
An image forming apparatus.

Images