JP5202968B2 - Single layer type electrophotographic photosensitive member and image forming apparatus - Google Patents

Description

  The present invention relates to a single-layer type electrophotographic photosensitive member and an image forming apparatus, and in particular, the occurrence of filming on the surface of the photosensitive layer and the occurrence of black spots in the formed image caused by any use environment. The present invention relates to a single-layer electrophotographic photosensitive member and an image forming apparatus that can be effectively suppressed.

  Conventionally, as an electrophotographic photosensitive member used in an image forming apparatus or the like, an organic photosensitive member composed of a binder resin, a charge generating agent, a charge transporting agent, and the like has been used. Such an organic photoreceptor is advantageous in that it is easy to manufacture and has a wide degree of freedom in structural design because it has various options for the photoreceptor material as compared with conventional inorganic photoreceptors.

  On the other hand, an organic material used for an organic photoreceptor is required to satisfy various conditions in order to stably form a high quality image.

  In particular, the charge transport agent is (i) stable to light and heat, (ii) stable to ozone generated by corona discharge, and (iii) has a high charge transport capability. It is required to satisfy various conditions such as iv) high compatibility with the organic solvent and the binder resin, and (v) easy production and low cost.

  Therefore, 1,1,4,4-tetraphenyl-1,3-butadiene represented by the following general formula (23) is satisfied as such a charge transport agent that satisfies various conditions and has an excellent charge transport ability. An electrophotographic photoreceptor using a derivative is disclosed (for example, Patent Document 1).

(In the general formula (23), R ^a and R ^b are independent substituents, R ^a represents a di-lower alkylamino group, and R ^b represents a hydrogen atom or a di-lower alkylamino group.)
Japanese Patent Publication No. 7-21646 (Claims)

  However, the electrophotographic photosensitive member of Patent Document 1 takes into account the combination of the 1,1,4,4-tetraphenyl-1,3-butadiene derivative having a specific structure and the electron transport agent. It wasn't. As a result, when it was configured as a single-layer type electrophotographic photosensitive member, there was a problem that the sensitivity characteristics were remarkably deteriorated depending on the type of electron transport agent used in combination.

  Furthermore, when the electrophotographic photosensitive member of Patent Document 1 is configured as a single-layer type electrophotographic photosensitive member, the surface characteristics of the photosensitive layer are likely to deteriorate, particularly when image formation is performed under high temperature and high humidity conditions. There was a tendency for filming to occur easily on the surface of the photosensitive layer. As a result, there was a problem that black spots were likely to occur in the formed image.

  Therefore, filming and the generation of black spots caused by the filming can be suppressed, and the excellent charge transport ability of the 1,1,4,4-tetraphenyl-1,3-butadiene derivative can be exhibited more effectively. There has been a demand for a single-layer type electrophotographic photosensitive member that can be produced.

  Therefore, the present inventors use 1,1,4,4-tetraphenyl-1,3-butadiene having a specific structure as a hole transport agent in a single layer type electrophotographic photosensitive member, and an electron transport agent. It has been found that the surface characteristics of the photosensitive layer can be effectively improved by setting the solubility in the predetermined solvent in the predetermined range.

  As a result, even when image formation is performed under any use environment, the occurrence of filming on the surface of the photosensitive layer, and the occurrence of black spots in the formed image resulting therefrom can be effectively suppressed, Furthermore, the inventors have found that sensitivity characteristics can be stably maintained.

  That is, the object of the present invention is to effectively suppress the occurrence of filming on the surface of the photosensitive layer and the occurrence of black spots in the formed image due to any use environment. A single-layer electron capable of effectively maintaining the excellent charge transporting ability of 1,1,4,4-tetraphenyl-1,3-butadiene having a specific structure and stably maintaining sensitivity characteristics It is an object to provide a photographic photoreceptor and an image forming apparatus.

  According to the present invention, there is provided a single layer type electrophotographic photosensitive member having a photosensitive layer containing a charge generator, a hole transport agent, an electron transport agent and a binder resin in the same layer on a substrate, the hole transport agent. Is 1,1,4,4-tetraphenyl-1,3-butadiene represented by the following general formula (1), and the electron transport agent has a solubility in tetrahydrofuran (measurement temperature: 25 ° C.), A single-layer electrophotographic photosensitive member having a value in the range of 27 to 50% by weight is provided, and the above-described problems can be solved.

(In general formula (1), R ¹ and R ² are independent substituents, R ¹ represents a di-lower alkylamino group, and R ² represents a hydrogen atom or a di-lower alkylamino group.)
That is, by using 1,1,4,4-tetraphenyl-1,3-butadiene having a specific structure as a hole transporting agent and setting the solubility of the electron transporting agent in a predetermined solvent to a predetermined range, The dispersibility of 1,1,4,4-tetraphenyl-1,3-butadiene having a specific structure in the layer can be effectively improved.

  More specifically, an electron transfer agent having a predetermined solubility is dispersed by a specific interaction with 1,1,4,4-tetraphenyl-1,3-butadiene having a specific structure. The dispersibility of 1,1,4,4-tetraphenyl-1,3-butadiene having a specific structure in the photosensitive layer can be effectively improved by exhibiting a function as an auxiliary agent.

  As a result, since the surface characteristics of the photosensitive layer can be effectively improved, filming on the surface of the photosensitive layer and black spots in the formed image due to the filming can be caused under any use environment. It can be effectively suppressed.

  In addition, by improving the dispersibility of the charge transport agent in the photosensitive layer, the specific 1,1,4,4-tetraphenyl-1,3-butadiene inherently has excellent hole transport ability and ozone resistance. It is possible to effectively exhibit characteristics such as property and effectively maintain excellent sensitivity characteristics.

  In addition, the solubility with respect to tetrahydrofuran of an electron transfer agent has shown the maximum amount (g) of electron transfer agents which can be dissolved with respect to 100 g of tetrahydrofuran on 25 degreeC conditions.

In constructing the single-layer electrophotographic photosensitive member of the present invention, a resin film containing 1,1,4,4-tetraphenyl-1,3-butadiene represented by the general formula (1), formed on the substrate, when immersed against oleic acid triglyceride (resin film composition: with respect to polycarbonate Boneto 100 parts by weight of the resin represented by the general formula (1) 1,1,4,4 80 parts by weight of tetraphenyl-1,3-butadiene , resin film thickness: 30 μm, oleic acid triglyceride amount: 30 g, substrate outer diameter: 30 mm, substrate length (immersion length): 40 mm, temperature: 25 ° C., (Time: 20 hours), the elution amount of 1,1,4,4-tetraphenyl-1,3-butadiene represented by the general formula (1) with respect to the oleic acid triglyceride is set to a value within the range of 1 to 10 mg. Is preferred.

  By constituting in this way, the dispersibility of 1,1,4,4-tetraphenyl-1,3-butadiene itself having a specific structure in the photosensitive layer can be further improved.

  In constituting the single-layer electrophotographic photosensitive member of the present invention, the electron transport agent is preferably a compound represented by the following general formulas (2) to (4).

(In General Formula (2), R ⁴ is a halogen atom, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, and R ⁵ is a substituent group. A substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a group represented by —O—R ⁶ , wherein R ⁶ is carbon A substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a substituted or unsubstituted aralkyl group having 7 to 30 carbon atoms.

(In the general formula (3), R ⁷ and R ⁸ are each an independent substituent and represent a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms.)

(In the general formula (4), R ^{9 to} R ¹³ are each an independent substituent, which represents a hydrogen atom, a halogen atom, or a substituted or unsubstituted alkyl group having 1 to 8 carbon atoms.)
By comprising in this way, the solubility with respect to the predetermined solvent in an electron carrying agent can be easily adjusted to a predetermined range, 1,1,4,4-tetraphenyl-1, which has a specific structure A specific interaction with 3-butadiene can be exhibited more effectively.

  In constituting the single-layer electrophotographic photosensitive member of the present invention, the content of the electron transport agent is preferably set to a value in the range of 10 to 70 parts by weight with respect to 100 parts by weight of the binder resin.

  By comprising in this way, the specific interaction between 1,1,4,4-tetraphenyl-1,3-butadiene having a specific structure can be more effectively exhibited. In addition, the electron transport efficiency in the photosensitive layer is improved, and the sensitivity characteristics of the electrophotographic photosensitive member can be further improved.

  In constituting the single layer type electrophotographic photosensitive member of the present invention, the outer diameter of the substrate is preferably set to a value in the range of 10 to 25 mm.

  With this configuration, the image forming apparatus can be reduced in size, while filming on the surface of the photosensitive layer and generation of black spots in the formed image due to the filming can be effectively suppressed.

  Another aspect of the present invention is an image forming apparatus in which a charging unit, a developing unit, and a transfer unit are arranged around an electrophotographic photosensitive member, wherein the electrophotographic photosensitive member is a charge generating agent on a substrate, While being a single layer type electrophotographic photoreceptor having a photosensitive layer containing a hole transport agent, an electron transport agent and a binder resin in the same layer, the hole transport agent is represented by the following general formula (1): , 1,4,4-tetraphenyl-1,3-butadiene and the electron transport agent has a value in the range of 27 to 50% by weight as solubility in tetrahydrofuran (measurement temperature: 25 ° C.). An image forming apparatus comprising a layer type electrophotographic photosensitive member.

(In general formula (1), R ¹ and R ² are independent substituents, R ¹ represents a di-lower alkylamino group, and R ² represents a hydrogen atom or a di-lower alkylamino group.)
In other words, since a specific single-layer type electrophotographic photosensitive member having excellent surface characteristics of the photosensitive layer is mounted as the electrophotographic photosensitive member, filming on the surface of the photosensitive layer is possible under any use environment. And the occurrence of black spots in the formed image due to this can be effectively suppressed.

  Further, since the charge transfer agent is excellent in dispersibility in the photosensitive layer, excellent sensitivity characteristics can be effectively maintained.

  In configuring the image forming apparatus of the present invention, it is preferable that the developing unit is a simultaneous development cleaning system.

  Such a configuration can contribute to miniaturization and simplification of the image forming apparatus, and can also effectively suppress filming on the surface of the photosensitive layer and occurrence of black spots in the formed image due to the filming. Can do.

  The developing means here refers to a developing device for attaching toner to an electrostatic latent image formed on an electrophotographic photosensitive member using a developing roll.

  The simultaneous development cleaning method is a method in which the developing roller described above collects residual toner in the developing device while attaching toner to the electrostatic latent image formed on the electrophotographic photosensitive member. Show.

  In configuring the image forming apparatus of the present invention, it is preferable that any one of the charging unit, the developing unit, and the transfer unit is in contact with the electrophotographic photosensitive member.

  With this configuration, filming on the surface of the photosensitive layer generally tends to occur. However, in the present invention, since a specific single layer type electrophotographic photosensitive member is mounted, The occurrence of black spots in the formed image can be effectively suppressed.

[First Embodiment]
The first embodiment of the present invention is a single-layer electrophotographic photosensitive member having a photosensitive layer containing a charge generator, a hole transport agent, an electron transport agent and a binder resin in the same layer on a substrate, The hole transport agent is 1,1,4,4-tetraphenyl-1,3-butadiene represented by the general formula (1), and the electron transport agent is soluble in tetrahydrofuran (measurement temperature: 25 ° C. ) As a single-layer electrophotographic photosensitive member having a value within a range of 27 to 50% by weight.

Hereinafter, the single layer type electrophotographic photosensitive member as the first embodiment will be specifically described for each component.
1. Basic Configuration As shown in FIG. 1A, a single-layer type electrophotographic photoreceptor 10 of the present invention has a single photosensitive layer 14 provided on a substrate 12.

  In addition, the photosensitive layer contains 1,1,4,4-tetraphenyl-1,3-butadiene having a specific structure as a hole transporting agent, and the electron transporting agent has a predetermined solvent solubility. It is characterized by including the compound which is.

  In the single-layer electrophotographic photosensitive member of the present invention, as shown in FIG. 1B, an intermediate layer 16 is formed between the substrate 12 and the photosensitive layer 14 as long as the characteristics of the photosensitive member are not impaired. The single-layer electrophotographic photosensitive member 10 'may be used.

  As the substrate, various materials having conductivity can be used. For example, iron, aluminum, copper, tin, platinum, silver, vanadium, molybdenum, chromium, cadmium, titanium, nickel, palladium, indium, Dispersed with conductive fine particles such as stainless steel, brass, etc., plastic materials deposited or laminated with the above metals, glass coated with aluminum iodide, tin oxide, indium oxide, etc., or carbon black. Plastic materials etc. are mentioned.

  Further, the shape of the substrate may be any of a sheet shape, a drum shape, or the like according to the structure of the image forming apparatus to be used. The substrate itself has conductivity, or the surface of the substrate has conductivity. If you do.

  Moreover, when making the shape of a base | substrate into a drum shape, it is preferable to make the outer diameter into the value within the range of 10-25 mm.

  The reason for this is that the outer diameter of the substrate is in such a range, which can contribute to downsizing of the image forming apparatus. On the other hand, the filming on the surface of the photosensitive layer and the occurrence of black spots in the formed image resulting therefrom are also effective. This is because it can be suppressed.

The reason why the occurrence of filming on the surface of the photosensitive layer can be effectively suppressed despite the fact that the outer diameter of the substrate is relatively small will be described in detail later in the section of the photosensitive layer.
2. Photosensitive layer (1) Hole transport agent (1) -1 type In the single-layer type electrophotographic photoreceptor of the present invention, 1, 1, 4 represented by the general formula (1) described above as the hole transport agent. , 4-tetraphenyl-1,3-butadiene is used.

  The reason for this is that if it is a specific 1,1,4,4-tetraphenyl-1,3-butadiene, it originally has an excellent hole transporting ability and ozone resistance. This is because electrical characteristics including sensitivity characteristics can be effectively improved.

  However, the sensitivity characteristics of 1,1,4,4-tetraphenyl-1,3-butadiene having such a specific structure are remarkably deteriorated depending on the electron transfer agent used in combination, or the surface characteristics of the photosensitive layer are low. In some cases, the film is remarkably reduced and filming and black spots caused by the filming are likely to occur.

  In this regard, in the present invention, as will be described later, by using a compound having a solubility in a predetermined solvent as an electron transporting agent within a predetermined range, the problem with respect to the occurrence of black spots due to such sensitivity characteristics and filming, It can be solved effectively.

Such an effect is obtained by a specific interaction between 1,1,4,4-tetraphenyl-1,3-butadiene having a specific structure and an electron transporting agent having a predetermined solubility. Although it is conceivable, a specific effect will be described in the section of the electron transfer agent later.
(1) -2 Specific Example Further, specific examples of 1,1,4,4-tetraphenyl-1,3-butadiene represented by the general formula (1) include the following formulas (5) to (7). The compound (HTM-1 to 3) represented can be mentioned.

(1) -3 Synthesis Example A synthesis method of 1,1,4,4-tetraphenyl-1,3-butadiene having a specific structure will be described.

That is, first, a tri-lower alkyl ester of phosphoric acid is reacted with aniline by a known reaction to obtain a di-lower alkylaniline, and this is reacted with phosgene to obtain a di-lower alkylamino group-substituted benzophenone. This benzophenone derivative is reacted with a Grignard reagent prepared from methyl bromide and magnesium, and then treated with a saturated aqueous ammonium chloride solution to obtain a 1,1-diphenylethylene derivative. Next, the 1,1-diphenylethylene derivative is reacted with a Vielsmeier reagent prepared from dimethylformamide and phosphorus oxychloride to obtain a 3,3-diphenylacrolein derivative. The resulting 3,3-diphenylacrolein derivative can be reacted with an equimolar or slightly excess 1,1-diphenylmethyl phosphite dialkyl compound to obtain compound (1).
The reaction of this acrolein compound and phosphorous acid compound is carried out in the presence of a basic catalyst at a temperature of about room temperature to 80 ° C. Examples of the basic catalyst include sodium hydride, sodium amide and sodium methylate, sodium t-butoxide, etc. The alcoholate is used. As solvents, lower alcohols such as methanol and ethanol; ethers such as 1,2-dimethoxyethane, ether, tetrahydrofuran, and dioxane; hydrocarbons such as toluene and xylene; dimethyl sulfoxide, N, N-dimethylformamide, N-methylpyrrolidone An aprotic polar solvent such as can be used.
(1) -4 Elution amount Further, a resin film containing 1,1,4,4-tetraphenyl-1,3-butadiene represented by the general formula (1) is formed on a substrate, and olein is formed. When immersed in acid triglycerides (resin film composition: 1,1,4,4-tetraphenyl-1,3- represented by the general formula (1) with respect to 100 parts by weight of polycarbonate resin) 80 parts by weight of butadiene , resin film thickness: 30 μm, substrate outer diameter: 30 mm, substrate length (immersion length): 40 mm, oleic acid triglyceride amount: 30 g, temperature: 25 ° C., time: 20 hours), The elution amount of 1,1,4,4-tetraphenyl-1,3-butadiene represented by the general formula (1) with respect to oleic acid triglyceride is preferably set to a value in the range of 1 to 10 mg.

  This is because the elution amount of 1,1,4,4-tetraphenyl-1,3-butadiene having a specific structure under a predetermined condition is within such a range, thereby having a specific structure 1 in the photosensitive layer. This is because the dispersibility of 1,1,4,4-tetraphenyl-1,3-butadiene itself can be further improved.

  That is, when the amount of elution of 1,1,4,4-tetraphenyl-1,3-butadiene having a specific structure is less than 1 mg, the compatibility with the organic material is excessively reduced, and in the photosensitive layer. This is because it may be difficult to sufficiently disperse. On the other hand, if the elution amount of 1,1,4,4-tetraphenyl-1,3-butadiene having a specific structure exceeds 10 mg, the dispersibility in the photosensitive layer is insufficient, and thus the photosensitive layer It is because it can be judged that it is easy to elute with respect to an oleic acid triglyceride from the layer surface.

Therefore, the elution amount of 1,1,4,4-tetraphenyl-1,3-butadiene having a specific structure under a predetermined condition is more preferably set to a value within the range of 3 to 8 mg. It is more preferable to set the value within the range.
(1) -5 Content Further, the content of 1,1,4,4-tetraphenyl-1,3-butadiene having a specific structure is set to 20 to 120 with respect to 100 parts by weight of the binder resin in the photosensitive layer. A value within the range of parts by weight is preferred.

  This is because, when the content of 1,1,4,4-tetraphenyl-1,3-butadiene having a specific structure is less than 20 parts by weight, sufficient sensitivity characteristics can be obtained in the electrophotographic photoreceptor. This is because it may be difficult. On the other hand, when the content of 1,1,4,4-tetraphenyl-1,3-butadiene having a specific structure exceeds 120 parts by weight, an electron transport agent having predetermined characteristics is used in combination. Even if it exists, it is because it may become difficult to fully disperse | distribute in a photosensitive layer.

Therefore, the content of 1,1,4,4-tetraphenyl-1,3-butadiene having a specific structure is a value within the range of 30 to 100 parts by weight with respect to 100 parts by weight of the binder resin in the photosensitive layer. It is more preferable that the value be in the range of 50 to 100 parts by weight.
(2) Electron Transfer Agent (2) -1 Solubility In the single-layer electrophotographic photoreceptor of the present invention, the electron transport agent has a solubility in tetrahydrofuran (measurement temperature: 25 ° C.) in the range of 27 to 50% by weight. It has the value of.

  The reason is that 1,1,4,4-tetraphenyl-1,3-butadiene having a specific structure is used as the hole transport agent, and the solubility of the electron transport agent in a predetermined solvent is within a predetermined range. This is because the dispersibility of 1,1,4,4-tetraphenyl-1,3-butadiene having a specific structure in the photosensitive layer can be effectively improved.

  That is, an electron transport agent having a predetermined solubility is used as a dispersion aid for such a compound by a specific interaction with 1,1,4,4-tetraphenyl-1,3-butadiene having a specific structure. The dispersibility of 1,1,4,4-tetraphenyl-1,3-butadiene having a specific structure in the photosensitive layer can be effectively improved.

  As a result, since the surface characteristics of the photosensitive layer can be effectively improved, filming on the surface of the photosensitive layer and black spots in the formed image due to the filming can be caused under any use environment. It can be effectively suppressed.

  In addition, by improving the dispersibility of the charge transport agent in the photosensitive layer, the specific 1,1,4,4-tetraphenyl-1,3-butadiene inherently has excellent hole transport ability and ozone resistance. It is possible to effectively exhibit characteristics such as property and effectively maintain excellent sensitivity characteristics.

  More specifically, when the solubility of the electron transport agent in tetrahydrofuran is less than 27% by weight, a specific mutual relationship with 1,1,4,4-tetraphenyl-1,3-butadiene having a specific structure is obtained. This is because it may be difficult to sufficiently exert the action, and it may be difficult to suppress filming and black spots caused by the filming. On the other hand, when the solubility of the electron transfer agent in tetrahydrofuran exceeds 50% by weight, the dispersibility of 1,1,4,4-tetraphenyl-1,3-butadiene having a specific structure can be improved. However, it is difficult to ensure a predetermined electron mobility or the mechanical strength of the photosensitive layer may be excessively lowered.

  Therefore, the solubility of the electron transport agent in tetrahydrofuran is more preferably set to a value within the range of 27 to 40% by weight, and further preferably set to a value within the range of 27 to 35% by weight.

  In addition, the solubility with respect to tetrahydrofuran of an electron transfer agent has shown the maximum amount (g) of electron transfer agents which can be dissolved with respect to 100 g of tetrahydrofuran on 25 degreeC conditions.

  Next, with reference to FIG. 2, the relationship between the solubility of the electron transport agent in tetrahydrofuran and the type of the hole transport agent and the number of black spots generated in the formed image will be described.

  That is, FIG. 2 shows a characteristic curve in which the horizontal axis represents the solubility (% by weight) of tetrahydrofuran in the electron transfer agent and the vertical axis represents the number of black spots (number of pieces / A4 paper) in the formed image.

  Here, the characteristic curve A is a compound represented by the formula (5) which is 1,1,4,4-tetraphenyl-1,3-butadiene represented by the general formula (1) as a hole transport agent ( HTM-1) is a characteristic curve, and the characteristic curve B is other than 1,1,4,4-tetraphenyl-1,3-butadiene represented by the general formula (1) as a hole transport agent. It is a characteristic curve at the time of using the compound (HTM-4) represented by following formula (8) which is a compound of this.

  The content of the hole transport agent was 50 parts by weight with respect to 100 parts by weight of the binder resin, and the content of the electron transport agent was 30 parts by weight with respect to 100 parts by weight of the binder resin.

  In addition, details of the configuration of the electrophotographic photosensitive member, the measurement conditions of the number of black spots, and the like will be described in later examples.

  First, as understood from the characteristic curve A, when 1,1,4,4-tetraphenyl-1,3-butadiene represented by the general formula (1) is used as the hole transport agent, electrons As the solubility of the transport agent increases, the number of sunspots generated decreases rapidly.

  More specifically, as the solubility of the electron transport agent increases from 20% by weight to 27% by weight, the number of sunspots rapidly increases from at least 150 / A4 paper to 50 / A4. It turns out that it is decreasing. It can be seen that when the solubility of the electron transfer agent is 27% by weight or more, the number of black spots generated can be stably maintained at around 50 / A4.

  On the other hand, as understood from the characteristic curve B, when a compound other than 1,1,4,4-tetraphenyl-1,3-butadiene represented by the general formula (1) is used as the hole transport agent. Even when the solubility of the electron transport agent is changed, the number of black spots generated does not decrease.

  More specifically, it can be seen that, regardless of the solubility of the electron transfer agent, the number of black spots generated is in the range of about 200 / A4, and the number of black spots generated cannot be effectively suppressed.

  Therefore, from the characteristic curves A and B, when 1,1,4,4-tetraphenyl-1,3-butadiene having a specific structure and an electron transport agent having a predetermined solubility are used in combination. It can be seen that unpredictable interaction is exhibited and the occurrence of black spots can be effectively suppressed as compared to the case of using other combinations.

  Next, the relationship between the occurrence of black spots in the formed image and the surface characteristics of the photosensitive layer will be described with reference to FIG.

  Here, as an index of the surface characteristics of the photosensitive layer, the elution amount of the hole transport agent from the photosensitive layer with respect to oleic acid triglyceride is used.

  That is, the larger the elution amount of the hole transport agent from the photosensitive layer with respect to oleic acid triglyceride, the more unevenly the hole transport agent is dispersed on the surface of the photosensitive layer, and consequently the surface characteristics of the photosensitive layer. This is because it indicates that is non-uniform.

  Furthermore, it is because the surface property of the photosensitive layer is likely to be further deteriorated by the fact that the hole transport agent is actually eluted from the surface of the photosensitive layer.

  That is, in FIG. 3, the horizontal axis represents the number of black spots (A4) in the formed image, and the vertical axis represents the elution amount (mg) of the hole transport agent from the photosensitive layer with respect to oleic acid triglyceride. Is shown.

  As understood from the characteristic curve, as the number of sunspots increases, the elution amount of the hole transport agent from the photosensitive layer with respect to oleic acid triglyceride increases.

  This indicates that the occurrence of black spots in the formed image is closely related to the surface characteristics of the photosensitive layer.

Therefore, the specific interaction between 1,1,4,4-tetraphenyl-1,3-butadiene having a specific structure and an electron transport agent having a predetermined solubility has an effect on the surface characteristics of the photosensitive layer. It is understood that, as a result of this effect, filming on the surface of the photosensitive layer is suppressed, and as a result, generation of black spots in the formed image is suppressed.
(2) -2 Types In addition, the type of the electron transport agent having a predetermined solubility is not particularly limited, and various conventionally known electron transport compounds can be used, but particularly preferred electron transport. The agent is preferably a compound represented by the general formulas (2) to (4) described above.

The reason for this is that if the electron transporting agent has these structures, the solubility of the electron transporting agent in a predetermined solvent can be easily adjusted to a predetermined range, and 1, 1, 4 having a specific structure. This is because the specific interaction with, 4-tetraphenyl-1,3-butadiene can be more effectively exhibited.
(2) -3 Specific Example Further, specific examples of the compounds represented by the general formulas (2) to (4) include compounds represented by the following formulas (13) to (15) (ETM-1 to ETM-3). ).

(2) -4 Content The content of the electron transport agent is preferably set to a value within the range of 10 to 70 parts by weight with respect to 100 parts by weight of the binder resin.

  This is because the specific interaction between 1,1,4,4-tetraphenyl-1,3-butadiene having a specific structure is achieved by setting the content of the electron transfer agent in such a range. This is because the electron transport efficiency in the photosensitive layer can be improved and the sensitivity characteristics of the electrophotographic photosensitive member can be improved.

  That is, when the content of the electron transport agent is less than 10 parts by weight, a specific interaction with 1,1,4,4-tetraphenyl-1,3-butadiene having a specific structure is achieved. This is because not only it is difficult to achieve sufficient performance, but also the electron transport efficiency may be excessively lowered. On the other hand, if the content of the electron transport agent exceeds 70 parts by weight, the content of the electron transport agent becomes excessive, and the electron transport agent itself has a specific structure. This is because it may cause a decrease in the dispersibility of phenyl-1,3-butadiene.

  Therefore, the content of the electron transport agent relative to 100 parts by weight of the binder resin is more preferably set to a value within the range of 20 to 60 parts by weight, and further preferably set to a value within the range of 20 to 50 parts by weight.

  Next, the relationship between the content of the electron transport agent and the number of black spots generated in the formed image will be described with reference to FIG.

  That is, FIG. 4 shows a characteristic curve in which the horizontal axis represents the content (parts by weight) of the electron transport agent relative to 100 parts by weight of the binder resin, and the vertical axis represents the number of black spots generated (number of pieces / A4 paper) in the formed image. Is shown.

  Here, the characteristic curve A is a characteristic curve when the compound (ETM-2) represented by the formula (14) which is a compound having a predetermined solubility is used as an electron transport agent, and the characteristic curve B is It is a characteristic curve at the time of using the compound (ETM-4) represented by following formula (16) which is an electron transport agent which does not have predetermined | prescribed solubility as an electron transport agent.

  In addition, as the hole transport agent, 50 parts by weight of 1,1,4,4-tetraphenyl-1,3-butadiene represented by the general formula (1) is contained with respect to 100 parts by weight of the binder resin. It was.

  In addition, details of the configuration of the electrophotographic photosensitive member, the measurement conditions of the number of black spots, and the like will be described in later examples.

  First, as understood from the characteristic curve A, when a compound having a predetermined solubility is used as the electron transport agent, the number of black spots generated is increased even when the content of the electron transport agent is widely changed. It turns out that it can suppress stably to the number of 50 piece / A4 paper vicinity.

  In the characteristic curve of FIG. 4, the content of the electron transport agent is merely changed within a range of 20 to 40 parts by weight, but the content of the electron transport agent is 10 to 70 parts by weight. It has been separately confirmed that even when the value is changed within the range, the number of black spots can be stably suppressed to 50 / A4 paper.

  On the other hand, as understood from the characteristic curve B, when a compound having a predetermined solubility is used as the electron transport agent, the number of black spots generated even when the content of the electron transport agent is changed. Has no significant effect.

  More specifically, as the content of the electron transport agent increases, the number of sunspots increases only slowly, and no effect of effectively reducing the number of sunspots is observed. I understand.

Therefore, from the characteristic curves A and B, it is unpredictable between 1,1,4,4-tetraphenyl-1,3-butadiene having a specific structure and an electron transporting agent having a predetermined solubility. By making the content of the electron transfer agent exhibiting the interaction and having a predetermined solubility within the range of 10 to 70 parts by weight, the interaction can be more effectively exhibited. Recognize.
(3) Charge Generator (3) -1 Type As the charge generator used in the electrophotographic photosensitive member of the present invention, a conventionally known charge generator can be used.

For example, phthalocyanine pigments, perylene pigments, bisazo pigments, diketopyrrolopyrrole pigments, metal-free naphthalocyanine pigments, metal naphthalocyanine pigments, squaraine pigments, trisazo pigments, indigo pigments, azurenium pigments, cyanine pigments, pyranium pigments, ansan Organic photoconductors such as throne pigments, triphenylmethane pigments, selenium pigments, toluidine pigments, pyrazoline pigments, quinacridone pigments, and inorganic photoconductors such as selenium, selenium-tellurium, selenium-arsenic, cadmium sulfide, and amorphous silicon Or a mixture of two or more of them.
(3) -2 Specific Example Further, among these charge generators, it is more preferable to use phthalocyanine pigments (CGM-A to D) represented by the following formulas (16) to (19). preferable.

(3) -3 Content Further, the content of the charge generating agent is preferably set to a value within the range of 0.2 to 40 parts by weight with respect to 100 parts by weight of the binder resin.

  The reason for this is that when the content of the charge generating agent is less than 0.2 parts by weight, the effect of increasing the quantum yield becomes insufficient, and the sensitivity characteristics, electrical characteristics, stability, etc. of the electrophotographic photoreceptor are improved. It is because it becomes impossible. On the other hand, when the content of the charge generating agent exceeds 40 parts by weight, the effect of increasing the extinction coefficient for light having a wavelength in the red region, near infrared region, or infrared region in visible light becomes insufficient. This is because the sensitivity characteristics, electrical characteristics, stability, and the like of the photoconductor may not be improved.

Therefore, the content of the charge generating agent is more preferably set to a value within the range of 0.5 to 20 parts by weight.
(4) Additive In addition to the above-described components, the photosensitive layer has various conventionally known additives such as an antioxidant, a radical scavenger, a single layer within the range that does not adversely affect the electrophotographic characteristics. A terminator, a deterioration inhibitor such as an ultraviolet absorber, a softener, a plasticizer, a surface modifier, a bulking agent, a thickener, a dispersion stabilizer, a wax, an acceptor, a donor, and the like can be blended. In order to improve the sensitivity of the photosensitive layer, for example, a known sensitizer such as terphenyl, halonaphthoquinones, acenaphthylene and the like may be used in combination with the charge generator.
(5) Binder resin As the binder resin, for example, a styrene polymer, a styrene-butadiene copolymer, a styrene-acrylonitrile copolymer, a styrene-maleic acid copolymer, an acrylic polymer, and a styrene-acrylic polymer are used. Copolymer, polyethylene, ethylene-vinyl acetate copolymer, chlorinated polyethylene, polyvinyl chloride, polypropylene, vinyl chloride-vinyl acetate copolymer, polyester, alkyd resin, polyamide, polyurethane, polycarbonate, polyarylate, polysulfone, diallyl Thermoplastic resins such as phthalate resin, ketone resin, polyvinyl butyral resin, and polyether resin, silicone resin, epoxy resin, phenol resin, urea resin, melamine resin, other cross-linkable thermosetting resins, and epoxy-acre relay And photocurable resins such as urethane-acrylate. These binder resins can be used alone or in combination of two or more.

  Moreover, it is preferable that water-repellent polycarbonate resin is included as binder resin.

  This is because the water-repellent polycarbonate resin facilitates the adjustment of the surface characteristics of the photosensitive layer and can more effectively suppress the occurrence of filming on the surface of the photosensitive layer.

  The water-repellent polycarbonate resin is also preferably included with a gradient so that the content ratio increases in the vicinity of the surface of the photosensitive layer.

  This is because the occurrence of filming can be effectively suppressed even with a relatively small amount of water-repellent polycarbonate resin.

  Moreover, it is preferable that the above-mentioned water-repellent polycarbonate resin includes a polycarbonate resin having a siloxane structure.

  This is because the surface characteristics of the photosensitive layer can be more easily adjusted with a polycarbonate resin having a siloxane structure.

That is, the siloxane structure part can exhibit excellent water repellency.
(6) Thickness The thickness of the photosensitive layer is preferably set to a value in the range of 5 to 100 μm.

  This is because if the thickness of the photosensitive layer is less than 5 μm, it may be difficult to form the photosensitive layer uniformly or the mechanical strength may be reduced. On the other hand, when the thickness of the photosensitive layer exceeds 100 μm, the photosensitive layer may be easily peeled off from the substrate.

Accordingly, the thickness of the photosensitive layer is more preferably set to a value within the range of 10 to 50 μm, and further preferably set to a value within the range of 15 to 45 μm.
(7) Manufacturing Method The manufacturing method of the electrophotographic photosensitive member is not particularly limited, but can be carried out by the following procedure.

  First, a coating solution is prepared by adding a charge generating agent, a charge transporting agent, a binder resin, an additive and the like to a solvent. The coating solution thus obtained is applied onto a conductive substrate (aluminum tube) using a coating method such as a dip coating method, a spray coating method, a bead coating method, a blade coating method, or a roller coating method. Apply.

  Thereafter, for example, it is dried with hot air at 100 ° C. for 40 minutes to obtain a single layer type electrophotographic photosensitive member having a photosensitive layer having a predetermined thickness.

  In addition, various organic solvents can be used as a solvent for preparing the dispersion, for example, alcohols such as methanol, ethanol, isopropanol and butanol; aliphatic hydrocarbons such as n-hexane, octane and cyclohexane. Aromatic hydrocarbons such as benzene, toluene and xylene, halogenated hydrocarbons such as dichloromethane, dichloroethane, chloroform, carbon tetrachloride and chlorobenzene; dimethyl ether, diethyl ether, tetrahydrofuran, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, 1,3- Ethers such as dioxolane and 1,4-dioxane; ketones such as acetone, methyl ethyl ketone and cyclohexanone; esters such as ethyl acetate and methyl acetate; dimethylformaldehyde; Methylformamide, dimethyl sulfoxide, and the like. These solvents are used alone or in admixture of two or more. At this time, in order to improve the dispersibility of the charge generating agent and the smoothness of the surface of the photosensitive layer, a surfactant, a leveling agent and the like may be added.

  It is also preferable to form an intermediate layer on the substrate before forming this photosensitive layer.

  In forming this intermediate layer, a binder resin and, if necessary, an additive (organic fine powder or inorganic fine powder) together with an appropriate dispersion medium, a known method such as a roll mill, a ball mill, an attritor, a paint shaker, A coating solution is prepared by dispersing and mixing using a sonic disperser or the like, and this is applied by a known means such as a blade method, a dipping method, or a spray method, and heat treatment is performed to form an intermediate layer.

  In addition, the additive is in a range where precipitation during production does not become a problem, and various additives (organic fine powder or inorganic fine powder are used for the purpose of preventing the occurrence of interference fringes by causing light scattering. ) Can be added in small amounts.

  Next, the obtained coating solution is applied to a support substrate (aluminum base tube) according to a known production method, such as dip coating, spray coating, bead coating, blade coating, roller coating, etc. It can apply | coat using the apply | coating method.

Then, it is preferable to perform the process of drying the coating liquid on a base | substrate at the temperature of 20-200 degreeC for 5 minutes-2 hours.
[Second Embodiment]
The second embodiment is an image forming apparatus in which a charging unit, a developing unit, and a transfer unit are arranged around an electrophotographic photosensitive member, and the electrophotographic photosensitive member has a charge generating agent and a hole transport on a substrate. 1, 1, 4 represented by the general formula (1), in addition to a single layer type electrophotographic photosensitive member having a photosensitive layer containing an agent, an electron transport agent and a binder resin in the same layer. , 4-tetraphenyl-1,3-butadiene, and the electron transporting agent has a solubility in tetrahydrofuran (measurement temperature: 25 ° C.) having a value in the range of 27 to 50% by weight. The image forming apparatus is a photoconductor.

  Hereinafter, the image forming apparatus as the second embodiment will be described focusing on the points different from the contents described in the first embodiment.

  The image forming apparatus of the second embodiment can be configured as a copying machine 30 as shown in FIG. 5, for example. The copying machine 30 includes an image forming unit 31, a paper discharge unit 32, an image reading unit 33, and a document feeding unit 34. The image forming unit 31 further includes an image forming unit 31a and a paper feeding unit 31b. In the illustrated example, the document feeding unit 34 includes a document placing tray 34a, a document feeding mechanism 34b, and a document discharge tray 34c, and the document placed on the document placing tray 34a. Is fed to the image reading position P by the document feeding mechanism 34b and then discharged to the document discharge tray 34c.

  Then, when the original is sent to the original reading position P, the image reading unit 33 reads the image on the original using the light from the light source 33a. That is, an image signal corresponding to the image on the document is formed using an optical element 33b such as a CCD.

  On the other hand, recording sheets (hereinafter simply referred to as “sheets”) S stacked on the sheet feeding unit 31b are sent one by one to the image forming unit 31a. The image forming unit 31a is provided with a photoconductive drum 41 as an image carrier. Further, around the photoconductive drum 41, a charger 42, an exposure unit 43, a developing unit 44, and a transfer roller. 45 is arranged along the rotation direction of the photosensitive drum 41.

  Among these components, the photosensitive drum 41 is rotationally driven in the direction indicated by the solid line arrow in the drawing, and the surface thereof is uniformly charged by the charger 42. Thereafter, an exposure process is performed on the photosensitive drum 41 by the exposure device 43 based on the above-described image signal, and an electrostatic latent image is formed on the surface of the photosensitive drum 41.

  Based on the electrostatic latent image, the developing unit 44 attaches toner and develops it, thereby forming a toner image on the surface of the photosensitive drum 41. The toner image is transferred as a transfer image onto the sheet S conveyed to the nip portion between the photosensitive drum 41 and the transfer roller 45. Next, the sheet S to which the transferred image is transferred is conveyed to the fixing unit 47 and a fixing process is performed.

  The photosensitive drum 41 is characterized by using the electrophotographic photosensitive member described in the first embodiment.

  Further, the sheet S after fixing is sent to the paper discharge unit 32. However, when performing post-processing (for example, stapling processing), the paper S is sent to the intermediate tray 32a and then post-processed. Is done. Thereafter, the sheet S is discharged to a discharge tray portion (not shown) provided on the side surface of the image forming apparatus. On the other hand, when no post-processing is performed, the sheet S is discharged to a discharge tray 32b provided below the intermediate tray 32a. The intermediate tray 32a and the paper discharge tray 32b are configured as a so-called in-body paper discharge unit.

  Since the image forming apparatus of the present invention includes a predetermined electrophotographic photosensitive member, it can stably form a clear image that effectively suppresses the generation of black spots under any use conditions. And excellent sensitivity characteristics can be effectively retained.

  Further, it is preferable that the developing means in the image forming apparatus of the present invention is a development simultaneous cleaning system.

  This is because the simultaneous development cleaning method can contribute to the miniaturization and simplification of the image forming apparatus, while the filming on the surface of the photosensitive layer and the generation of black spots in the formed image resulting therefrom are effective. This is because it can be suppressed.

  That is, since the electrophotographic photosensitive member used in the present invention has excellent surface characteristics, even when the simultaneous development cleaning method is employed, the occurrence of filming and black spots caused by the filming are sufficiently obtained. It is because generation | occurrence | production of can be suppressed.

  In addition, it is preferable that any one of the above-described charging unit, developing unit, and transfer unit is in contact with the electrophotographic photosensitive member.

  The reason for this is that when these methods are brought into contact with the electrophotographic photosensitive member, filming on the surface of the photosensitive layer generally tends to occur. This is because, since the photographic photosensitive member is mounted, filming and the occurrence of black spots in the formed image resulting therefrom can be effectively suppressed.

  More specifically, a transfer belt is preferably used as the transfer unit, and a charging roller is preferably used as the charging unit.

  That is, when a transfer belt or a charging roller is used, filming on the surface of the photosensitive layer is more likely to occur due to bleeding that generally occurs in the transfer belt or the charging roller. On the other hand, according to the present invention, since a specific single layer type electrophotographic photosensitive member is mounted, it is possible to effectively suppress filming and the generation of black spots due to the formation. .

Hereinafter, based on an Example, this invention is demonstrated in detail.
[Example 1]
1. Production of Single Layer Type Electrophotographic Photoreceptor In the container, 4 parts by weight of X-type metal-free phthalocyanine (CGM-A) represented by formula (16) as a charge generating agent and formula (5 ) 50 parts by weight of the compound (HTM-1), 30 parts by weight of the compound (ETM-1) represented by the formula (13) as an electron transporting agent, and a viscosity average molecular weight of 30 as a binder resin. 100 parts by weight of polycarbonate resin of 1,000, and 800 parts by weight of tetrahydrofuran as a solvent were accommodated.

Subsequently, it was mixed and dispersed in a ball mill for 50 hours to prepare a coating solution for the photosensitive layer. Next, the obtained coating solution was applied on a base (aluminum base tube) having a diameter of 16 mm and a length of 254 mm by a dip coating method and dried with hot air at 100 ° C. for 40 minutes to obtain a film thickness of 25 μm. A single layer type electrophotographic photosensitive member having a single layer type photosensitive layer was obtained.
2. Evaluation of Single Layer Type Electrophotographic Photoreceptor (1) Measurement of Elution Amount of Hole Transport Agent The elution amount of the hole transport agent from the photosensitive layer was measured.

  That is, on a substrate having an outer diameter of 30 mm, a coating solution for a photosensitive layer prepared when a single-layer electrophotographic photosensitive member is manufactured is formed to form a photosensitive layer having a thickness of 30 μm, and then the photosensitive layer is formed. Amount of hole transport agent eluted from the surface of the photosensitive layer (mg) when immersed in 30 g of oleic acid triglyceride at 25 ° C. for 20 hours so that the immersion length is 40 mm together with the substrate. ) Was measured.

  For the measurement of the amount of the eluted hole transport agent, first, the same hole transport agent as that to be measured is previously dissolved in oleic acid triglyceride so as to have a predetermined concentration, and the ultraviolet absorbance (wavelength: 350 to 350- Any two wavelengths in the range of 450 nm) were measured, and the ratio between the absorbance and the concentration of the hole transporting agent was determined.

  Subsequently, the ultraviolet light absorbency in the oleic acid triglyceride after the photosensitive layer was immersed was measured, and the amount of the hole transport agent eluted from the photosensitive layer was calculated. The obtained results are shown in Table 1.

  In addition to the elution amount of the hole transport agent from the photosensitive layer, a resin film containing only the hole transport agent in the binder resin is prepared, and the elution amount of the hole transport agent from the resin film. Was measured.

  That is, after forming a resin film having a hole transport agent content of 80 parts by weight with respect to 100 parts by weight of the polycarbonate resin on a substrate having an outer diameter of 30 mm and a film thickness of 30 μm, the resin film is applied to the substrate. At the same time, the amount of the hole transport agent eluted from the surface of the resin film (mg) when immersed in 30 g of oleic acid triglyceride at 25 ° C. for 20 hours so that the immersion length is 40 mm. ) Was measured.

In addition, as a measuring method, it measured similarly to the amount of positive hole transport agents eluted from the photosensitive layer mentioned above.
(2) Measurement of the number of black spots generated The obtained single-layer type electrophotographic photosensitive member is mounted on a printer (DP-560, manufactured by Kyocera Mita Corporation), and the environment is 40 ° C. and the relative humidity is 90% Rh. Under the conditions, 5,000 sheets of A4 paper (Fuji Xerox high-quality PPC paper) were continuously printed on a 6% original image. Then, after leaving the printer for 6 hours, a blank original was printed on A4 paper, the number of black spots generated on the A4 paper was counted, and evaluated according to the following criteria. The obtained results are shown in Table 1.
A: The number of black spots generated per A4 paper is less than 50.
A: The number of black spots generated per A4 paper is less than 50 to 100.
X: The number of black spots generated per A4 paper is 100 or more.
(3) Measurement of sensitivity The sensitivity of the obtained single-layer type electrophotographic photosensitive member was measured under the following conditions.

That is, using a drum sensitivity tester (produced by GENTEC Co., Ltd.), the surface potential of the single-layer electrophotographic photosensitive member was taken out from the white light of the halogen lamp using a bandpass filter while being charged to + 700V. Monochromatic light having a wavelength of 780 nm (half-width 20 nm, light intensity 0.6 μJ / cm ² ) was irradiated to the surface of the single-layer electrophotographic photosensitive member for 50 msec. Next, the surface potential at the time when 0.35 seconds passed from the start of exposure was measured as sensitivity (V). The obtained sensitivity results are shown in Table 1.
[Example 2]
In Example 2, a single-layer electrophotographic photosensitive member was produced and evaluated in the same manner as in Example 1 except that the compound (ETM-2) represented by the formula (14) was used as the electron transport agent. The obtained results are shown in Table 1.
[Example 3]
In Example 3, a single-layer electrophotographic photosensitive member was produced and evaluated in the same manner as in Example 2 except that the content of the electron transport agent was changed to 20 parts by weight. The obtained results are shown in Table 1.
[Example 4]
In Example 4, a single-layer electrophotographic photosensitive member was produced and evaluated in the same manner as in Example 2 except that the content of the electron transport agent was changed to 40 parts by weight. The obtained results are shown in Table 1.
[Example 5]
In Example 5, a single-layer electrophotographic photosensitive member was produced and evaluated in the same manner as in Example 4 except that the compound (ETM-3) represented by the formula (15) was used as the electron transport agent. The obtained results are shown in Table 1.
[Example 6]
In Example 6, a single-layer electrophotographic photosensitive member was produced and evaluated in the same manner as in Example 1 except that the compound (HTM-2) represented by the formula (6) was used as the hole transport agent. The obtained results are shown in Table 1.
[Example 7]
In Example 7, a single-layer electrophotographic photosensitive member was produced and evaluated in the same manner as in Example 6 except that the compound (ETM-2) represented by the formula (14) was used as the electron transport agent. The obtained results are shown in Table 1.
[Example 8]
In Example 8, a single-layer electrophotographic photosensitive member was produced and evaluated in the same manner as in Example 6 except that the compound (ETM-3) represented by the formula (15) was used as the electron transport agent. The obtained results are shown in Table 1.
[Example 9]
In Example 9, a single-layer electrophotographic photosensitive member was produced and evaluated in the same manner as in Example 1 except that the compound (HTM-3) represented by the formula (7) was used as the hole transport agent. The obtained results are shown in Table 1.
[Example 10]
In Example 10, a single-layer electrophotographic photosensitive member was produced and evaluated in the same manner as in Example 9 except that the compound (ETM-2) represented by the formula (14) was used as the electron transport agent. The obtained results are shown in Table 1.
[Example 11]
In Example 11, a single-layer electrophotographic photosensitive member was produced and evaluated in the same manner as in Example 9 except that the compound (ETM-3) represented by the formula (15) was used as the electron transport agent. The obtained results are shown in Table 1.
[Comparative Example 1]
In Comparative Example 1, a single-layer electrophotographic photosensitive member was produced and evaluated in the same manner as in Example 1 except that the compound (HTM-4) represented by the formula (8) was used as the hole transport agent. The obtained results are shown in Table 1.
[Comparative Example 2]
In Comparative Example 2, a single-layer electrophotographic photosensitive member was produced and evaluated in the same manner as Comparative Example 1 except that the compound (ETM-2) represented by the formula (14) was used as the electron transport agent. The obtained results are shown in Table 1.
[Comparative Example 3]
In Comparative Example 3, a single-layer electrophotographic photosensitive member was produced and evaluated in the same manner as in Comparative Example 1 except that the compound (ETM-3) represented by the formula (15) was used as the electron transport agent. The obtained results are shown in Table 1.
[Comparative Example 4]
In Comparative Example 4, a single-layer electrophotographic photosensitive member was produced and evaluated in the same manner as in Comparative Example 1 except that the compound (ETM-4) represented by the formula (16) was used as the electron transport agent. The obtained results are shown in Table 1.
[Comparative Example 5]
In Comparative Example 5, a single-layer electrophotographic photosensitive member was produced and evaluated in the same manner as in Example 1 except that the compound (HTM-5) represented by the following formula (9) was used as the hole transport agent. . The obtained results are shown in Table 1.

[Comparative Example 6]
In Comparative Example 6, a single-layer electrophotographic photosensitive member was produced and evaluated in the same manner as in Comparative Example 5 except that the compound (ETM-2) represented by the formula (14) was used as the electron transport agent. The obtained results are shown in Table 1.
[Comparative Example 7]
In Comparative Example 7, a single-layer electrophotographic photosensitive member was produced and evaluated in the same manner as Comparative Example 5 except that the compound (ETM-3) represented by the formula (15) was used as the electron transport agent. The obtained results are shown in Table 1.
[Comparative Example 8]
In Comparative Example 8, a single-layer electrophotographic photosensitive member was produced and evaluated in the same manner as in Comparative Example 5 except that the compound (ETM-4) represented by the formula (16) was used as the electron transport agent. The obtained results are shown in Table 1.
[Comparative Example 9]
In Comparative Example 9, a single-layer electrophotographic photosensitive member was produced and evaluated in the same manner as in Example 1 except that the compound (HTM-6) represented by the following formula (10) was used as the hole transport agent. . The obtained results are shown in Table 1.

[Comparative Example 10]
In Comparative Example 10, a single-layer electrophotographic photosensitive member was produced and evaluated in the same manner as Comparative Example 9 except that the compound (ETM-2) represented by the formula (14) was used as the electron transport agent. The obtained results are shown in Table 1.
[Comparative Example 11]
In Comparative Example 11, a single-layer electrophotographic photosensitive member was produced and evaluated in the same manner as Comparative Example 9, except that the compound (ETM-3) represented by the formula (15) was used as the electron transport agent. The obtained results are shown in Table 1.
[Comparative Example 12]
In Comparative Example 12, a single-layer electrophotographic photosensitive member was produced and evaluated in the same manner as Comparative Example 9, except that the compound (ETM-4) represented by the formula (16) was used as the electron transport agent. The obtained results are shown in Table 1.
[Comparative Example 13]
In Comparative Example 13, a single-layer electrophotographic photosensitive member was produced and evaluated in the same manner as in Example 1 except that the compound (HTM-7) represented by the following formula (11) was used as the hole transport agent. . The obtained results are shown in Table 1.

[Comparative Example 14]
In Comparative Example 14, a single-layer electrophotographic photosensitive member was produced and evaluated in the same manner as Comparative Example 13 except that the compound (ETM-2) represented by the formula (14) was used as the electron transport agent. The obtained results are shown in Table 1.
[Comparative Example 15]
In Comparative Example 15, a single-layer electrophotographic photosensitive member was produced and evaluated in the same manner as in Comparative Example 13, except that the compound (ETM-3) represented by the formula (15) was used as the electron transport agent. The obtained results are shown in Table 1.
[Comparative Example 16]
In Comparative Example 16, a single-layer electrophotographic photosensitive member was produced and evaluated in the same manner as in Example 1 except that the compound (HTM-8) represented by the following formula (12) was used as the hole transport agent. . The obtained results are shown in Table 1.

[Comparative Example 17]
In Comparative Example 17, a single-layer electrophotographic photosensitive member was produced and evaluated in the same manner as in Comparative Example 16, except that the compound (ETM-2) represented by the formula (14) was used as the electron transport agent. The obtained results are shown in Table 1.
[Comparative Example 18]
In Comparative Example 18, a single-layer electrophotographic photosensitive member was produced and evaluated in the same manner as in Comparative Example 16, except that the compound (ETM-3) represented by the formula (15) was used as the electron transport agent. The obtained results are shown in Table 1.
[Comparative Example 19]
In Comparative Example 19, the compound (HTM-1) represented by the formula (5) was used as the hole transport agent, and the compound (ETM-4) represented by the formula (16) was used as the electron transport agent. Were evaluated in the same manner as in Example 1 while producing a single-layer electrophotographic photosensitive member. The obtained results are shown in Table 1.
[Comparative Example 20]
In Comparative Example 20, a single-layer electrophotographic photosensitive member was produced and evaluated in the same manner as Comparative Example 19 except that the content of the electron transport agent was changed to 20 parts by weight. The obtained results are shown in Table 1.
[Comparative Example 21]
In Comparative Example 21, a single-layer electrophotographic photosensitive member was produced and evaluated in the same manner as Comparative Example 19 except that the content of the electron transport agent was changed to 40 parts by weight. The obtained results are shown in Table 1.
[Comparative Example 22]
In Comparative Example 22, a single-layer electrophotographic photosensitive member was produced and evaluated in the same manner as Comparative Example 19 except that the compound (ETM-5) represented by the following formula (22) was used as the electron transport agent. The obtained results are shown in Table 1.

  In the single-layer electrophotographic photoreceptor and the image forming apparatus according to the present invention, 1,1,4,4-tetraphenyl-1,3-butadiene having a specific structure is used as the hole transport agent, By setting the solubility of the transport agent in a predetermined solvent within a predetermined range, the surface characteristics of the photosensitive layer can be effectively improved.

  As a result, it is possible to effectively suppress the occurrence of filming on the surface of the photosensitive layer and the occurrence of black spots in the formed image caused by the image formation under any use environment. Furthermore, the excellent charge transporting ability of 1,1,4,4-tetraphenyl-1,3-butadiene having a specific structure can be effectively exhibited, and the sensitivity characteristics can be stably maintained. It became so.

  Therefore, the single-layer type electrophotographic photosensitive member and the image forming apparatus according to the present invention are expected to contribute significantly to improving the quality and extending the life of various image forming apparatuses such as copying machines and printers.

(A)-(b) is a figure provided in order to demonstrate the structure of the single layer type electrophotographic photoreceptor of this invention. FIG. 2 is a diagram provided for explaining the relationship between the solubility of the electron transport agent and the number of sunspots generated. FIG. 3 is a diagram for explaining the relationship between the number of black spots generated and the elution amount of the hole transport agent from the photosensitive layer. FIG. 4 is a diagram provided for explaining the relationship between the content of the electron transport agent and the number of sunspots generated. FIG. 5 is a diagram for explaining the structure of the image forming apparatus of the present invention.

Explanation of symbols

10: single layer type electrophotographic photosensitive member, 12: substrate, 14: photosensitive layer, 16: intermediate layer, 30: copying machine, 31: image forming unit, 31a: image forming unit, 31b: paper feeding unit, 32: discharge Paper unit 33: Image reading unit 33a: Light source 33b: Optical element 34: Document feeding unit 34a: Document loading tray 34b: Document feeding mechanism 34c: Document discharge tray 41: Photosensitive drum 42: charger, 43: exposure source, 44: developer, 45: transfer roller

Claims (8)

A single-layer electrophotographic photoreceptor having a photosensitive layer containing a charge generator, a hole transport agent, an electron transport agent and a binder resin in the same layer on a substrate,
The hole transport agent is a 1,1,4,4-tetraphenyl-1,3-butadiene derivative represented by the following general formula (1), and the electron transport agent has solubility (measurement in tetrahydrofuran). A single-layer electrophotographic photosensitive member having a value in the range of 27 to 50% by weight as a temperature (25 ° C.).

(In the general formula (1), R1 and R2 are independent substituents, R1 represents a di-lower alkylamino group, and R2 represents a hydrogen atom or a di-lower alkylamino group.) A resin film containing 1,1,4,4-tetraphenyl-1,3-butadiene represented by the general formula (1) was formed on the substrate and immersed in triglyceride oleate. If the (resin film composition: the polycarbonate resin 100 parts by weight, the formula (1,1,4,4-tetraphenyl-1,3-butadiene 80 parts by weight represented by 1), the resin thickness: 30 μm, substrate outer diameter: 30 mm, substrate length (immersion length): 40 mm, oleic acid triglyceride content: 30 g, temperature: 25 ° C., time: 20 hours), represented by the general formula (1) The monolayer type according to claim 1, wherein an elution amount of 1,1,4,4-tetraphenyl-1,3-butadiene with respect to oleic acid triglyceride is set to a value within a range of 1 to 10 mg. Electrophotographic photoreceptor. The single-layer electrophotographic photoreceptor according to claim 1 or 2, wherein the electron transfer agent is a compound represented by the following general formulas (2) to (4).

(In general formula (2), R4 is a halogen atom, a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, and R5 has a substituent. A substituted or unsubstituted alkyl group having 1 to 6 carbon atoms, a substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or a group represented by —O—R 6, wherein R 6 is 1 to 6 carbon atoms. Substituted or unsubstituted alkyl group, substituted or unsubstituted aryl group having 6 to 30 carbon atoms, or 7 to 30 carbon atoms
Represents a substituted or unsubstituted aralkyl group. )

(In general formula (3), R7 and R8 are each an independent substituent, and represent a substituted or unsubstituted alkyl group having 1 to 6 carbon atoms.)

(In the general formula (4), R9 to R13 are each an independent substituent, which represents a hydrogen atom, a halogen atom, or a substituted or unsubstituted alkyl group having 1 to 8 carbon atoms.) The content of the electron transport agent is set to a value within a range of 10 to 70 parts by weight with respect to 100 parts by weight of the binder resin. Layer type electrophotographic photoreceptor. The outer diameter of the substrate is set to a value within a range of 10 to 25 mm.
The image forming apparatus according to claim 1. An image forming apparatus in which a charging unit, a developing unit, and a transfer unit are arranged around an electrophotographic photosensitive member,
The electrophotographic photoreceptor is a single layer type electrophotographic photoreceptor having a photosensitive layer containing a charge generator, a hole transport agent, an electron transport agent and a binder resin in the same layer on a substrate,
The hole transfer agent is 1,1,4,4-tetraphenyl-1 represented by the following general formula (1)
, 3-butadiene, and the electron transport agent is a single-layer electrophotographic photosensitive member having a solubility in tetrahydrofuran (measurement temperature: 25 ° C.) having a value in the range of 27 to 50% by weight. An image forming apparatus.

(In the general formula (1), R 1 and R 2 are independent substituents, R 1 represents a di-lower alkylamino group, and R 2 represents a hydrogen atom or a di-lower alkylamino group.) The image forming apparatus according to claim 6, wherein the developing unit is a simultaneous development cleaning system. The image forming apparatus according to claim 6, wherein any one of the charging unit, the developing unit, and the transfer unit is in contact with the electrophotographic photosensitive member.