JP4898184B2 - 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 more particularly to a single-layer type electrophotographic photosensitive member that generates little black spots even when used for a long period of time, and such a single-layer type electrophotographic photoconductor. The present invention relates to an image forming apparatus provided with a photoreceptor.

  Conventionally, as an electrophotographic photoreceptor provided in an image forming apparatus or the like, an organic photoreceptor (OPC) composed of a binder resin (binder resin), a charge generator, a charge transport agent (a hole transport agent, an electron transport agent), and the like. ) Is 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.

  The organic photoreceptor includes an organic single-layer photoreceptor in which a binder resin, a charge generating agent, and a charge transporting agent (electron transporting agent, hole transporting agent) are dispersed on a single organic photosensitive layer on a substrate. In addition, an organic laminated photoreceptor including a charge generation layer containing a charge generation agent and a binder resin and a charge transport layer containing a charge transfer agent and a binder resin is known.

  Here, the organic single layer photoreceptor is often charged positively in the charging step, and the toner powder used as the developer of the organic single layer photoreceptor is charged to the same positive polarity as the charge polarity of the photoreceptor. Thus, the toner adheres to the portion where the potential is lowered by the light irradiation. The toner image formed on the surface of the photoreceptor in this way is transferred onto the transfer paper using electrostatic force. Since this transfer paper is negatively charged, negatively charged paper dust tends to adhere to the positively charged photoconductor, and the organic single-layer photoconductor has black spots, black streaks, etc. on the image. There were many problems that occurred.

  Therefore, as an electrophotographic photosensitive member having a function of suppressing the occurrence of filming, an electrophotographic photosensitive member having a repeating unit represented by the following general formula (51) in the photosensitive layer has been proposed (for example, see Patent Document 1). ).

(R in the general formula (51) is the same or different monovalent hydrocarbon group not containing an aliphatic unsaturated bond, and each R ²³ is independently a halogen atom, a substituted or unsubstituted group having 1 to 6 carbon atoms. An alkyl group, a substituted or unsubstituted alkoxy group having 1 to 6 carbon atoms, or a substituted or unsubstituted aryl group having 6 to 12 carbon atoms, and each X is independently an alkylene group having 2 or more carbon atoms or 2 or more carbon atoms X ′ is each independently an alkylene group having 2 or more carbon atoms, an alkyleneoxyalkylene group having 2 or more carbon atoms, or an oxygen atom, and a is each independently an integer of 0 to 4, na is 0 or 1, nb is 1 or 2, nc is 1 or 2, provided that na + nb + nc = 3, and n1, n2, n3 and n4 are each independently 0 or an integer of 1 or more ,However n1 + n2 + n3 is an integer of + n4 = 0~450.)

Further, in an image forming method including a step of cleaning toner remaining on a photosensitive member with a brush and an elastic rubber blade as an electrophotographic photosensitive member having a function of suppressing the occurrence of filming, the surface of the photosensitive member is treated with pure water. An image forming method having a contact angle of 90 ° or more is disclosed (see, for example, Patent Document 2).
JP-A-10-232503 (Claims) JP-A-10-31804 (Claims)

  However, although the electrophotographic photosensitive member described in Patent Document 1 contains a polycarbonate resin having a siloxane structure, the value of the contact angle is still low, when rotating at high speed, or when the rotating diameter is reduced, There was a problem that the filming characteristics could not be fully exhibited. Therefore, there has been a problem that silica or paper powder is likely to adhere to the surface of the photoreceptor, and as a result, black spots are easily generated.

In addition, the image forming method described in Patent Document 2 uses a brush and an elastic rubber blade as a cleaning member to clean the surface of the photoconductor, and suppresses the occurrence of filming. The contact angle with respect to pure water is limited to a value of 90 ° or more.
However, when used over a long period of time, the surface of the photoreceptor is worn by the cleaning member, and it is difficult to control the contact angle of the photoreceptor surface within a certain range. For this reason, there has been a problem that silica and paper powder are likely to adhere to the surface of the photoreceptor, and black spots are easily generated.

Therefore, the present inventors include a polycarbonate resin having a specific siloxane structure, and by making the contact angle of pure water with respect to the photoreceptor layer a value within a predetermined range, hole transport for the purpose of improving sensitivity. The present inventors have found that the problem of black spot generation associated with an increase in the additive amount of the agent and an increase in the polarity of the hole transport agent can be solved, and the present invention has been completed.
That is, an object of the present invention is to provide a single-layer electrophotographic photosensitive member that has excellent sensitivity characteristics even when used for a long time and generates few black spots, and image formation provided with such a single-layer electrophotographic photosensitive member. To provide an apparatus.

According to the present invention, there is provided a single layer type electrophotographic photosensitive member provided on the outermost surface with a photoreceptor layer containing a binder resin, a hole transport agent, and a charge generating agent, and as a binder resin, The polycarbonate resin having a siloxane structure is included in a value within a range of 35 to 60 parts by weight with respect to 100 parts by weight of the total amount of all components other than the solvent used in the photoreceptor layer, and When the total amount is 100 mol%, the content ratio of units having a siloxane structure is set to a value in the range of 2 to 20 mol%, and the contact angle of pure water to the polycarbonate resin having a siloxane structure (measurement temperature: 25 ° C.) is 98. and a value within the range of to 120 °, as a hole transporting agent, a compound having a triphenylamine skeleton containing stilbene structure, Porika having a siloxane structure 100 parts by weight of sulphonate resin to comprise a value within a range of 30 to 60 parts by weight, compounds having a triphenylamine skeleton containing stilbene structure, the contact angle with respect to the resin dispersion film (measuring temperature: 25 ° C.) is 90 It is a compound having a value within the range of 120 °, the contact angle of pure water with respect to the photoreceptor layer (measurement temperature: 25 ° C.) is set to a value within the range of 102 to 110 , and the thickness of the photoreceptor layer is A single-layer electrophotographic photosensitive member characterized by a value in the range of 25 to 50 μm is provided, and the above-described problems can be solved.

  In constituting the single-layer electrophotographic photosensitive member of the present invention, the viscosity average molecular weight of the polycarbonate resin having a siloxane structure is preferably set to a value within the range of 10,000 to 60,000.

Further, in constituting the single-layer type electrophotosensitive material of the present invention, the photosensitive layer is, as the electron transferring material, a naphthoquinone derivative, with respect to 100 parts by weight of a polycarbonate resin having a siloxane structure, a range of 20 to 80 parts by weight It is preferable to include the value within the range.

  In constituting the single-layer electrophotographic photosensitive member of the present invention, a phthalocyanine pigment as a charge generator is within a range of 0.5 to 20 parts by weight with respect to 100 parts by weight of a polycarbonate resin having a siloxane structure. It is preferable to include by value.

  In constituting the single-layer type electrophotographic photosensitive member of the present invention, the photosensitive layer has, as additives, compounds represented by the following formulas (34) to (35) and (38) to (40) (additives). It is preferred to contain at least one compound of the group consisting of -AB and EG).

  In constituting the single-layer electrophotographic photosensitive member of the present invention, the content of the additive is preferably set to a value in the range of 1.5 to 15% by weight with respect to the total amount of the photosensitive layer. .

  Another aspect of the present invention includes any one of the above-described single-layer type electrophotographic photoconductors, and performs a charging step, an exposure step, a development step, and a transfer step around the electrophotographic photoconductor. The image forming apparatus is characterized in that the part is arranged.

  In constructing the image forming apparatus of the present invention, it is preferable that the development process is a simultaneous development cleaning system.

  That is, according to the single-layer electrophotographic photosensitive member of the present invention, the silica resin contains a polycarbonate resin having a specific siloxane structure, and the contact angle of pure water with respect to the photosensitive layer is set to a value within a predetermined range. It effectively prevents the adhesion of paper dust and paper dust, and has excellent sensitivity characteristics even when used for a long time, and can effectively reduce the occurrence of black spots.

  In addition, according to the single-layer electrophotographic photosensitive member of the present invention, by adjusting the content ratio of the polycarbonate resin having a siloxane structure to a value within a predetermined range, the contact angle in the photosensitive layer can be easily adjusted, Further excellent durability can be obtained.

In addition, according to the single layer type electrophotographic photosensitive member of the present invention, since the resin dispersion film of the hole transport agent has a predetermined contact angle, it is further coupled with the water repellent function of the water repellent polycarbonate resin. It is possible to effectively prevent the adhesion of paper dust and paper dust and to efficiently reduce the generation of black spots.

  In addition, according to the single layer type electrophotographic photosensitive member of the present invention, by using a compound having a specific structure as a hole transporting agent, the contact angle in the photosensitive layer can be easily adjusted, and excellent sensitivity can be obtained. Characteristics can be obtained.

  Further, according to the single-layer electrophotographic photosensitive member of the present invention, by using a compound having a specific structure as an additive, it is possible to suppress the occurrence of cracks on the surface of the photosensitive member due to adhesion of contaminants and the like. As a result, it is possible to prevent the occurrence of black spots and fog in the image.

  In addition, according to the single-layer electrophotographic photosensitive member of the present invention, the content of the additive is set to a value within a predetermined range with respect to the total amount of the photosensitive layer, so that the photosensitive material caused by the adhesion of contaminants can be obtained. Since the occurrence of cracks on the body surface can be more effectively suppressed, the occurrence of black spots and fog in the image can be more effectively prevented.

Further, according to the image forming apparatus of the present invention, a predetermined single layer type electrophotographic photosensitive member is provided, and a charging step, an exposure step, a developing step, and a transfer step are performed around the electrophotographic photosensitive member. By arranging the portions, it is possible to provide an image forming apparatus that has excellent sensitivity characteristics over a long period of time, can efficiently reduce the value of the exposure memory, and prevents the occurrence of black spots and black streaks. That is, an image forming apparatus that can provide a clear image over a long period of time can be provided.
In addition, according to the image forming apparatus of the present invention, it is possible to omit the charge eliminating step. In this case, the image forming apparatus can be further miniaturized and the number of parts can be reduced to reduce the cost efficiently. Can also be planned.

  Further, according to the image forming apparatus of the present invention, the image forming apparatus can be simplified and further downsized by adopting the simultaneous development cleaning system.

[First embodiment]
The first embodiment is a single-layer electrophotographic photosensitive member provided on the outermost surface with a photoreceptor layer containing a binder resin, a hole transport agent, and a charge generating agent, as a binder resin And a polycarbonate resin having a siloxane structure and containing a polycarbonate resin having a siloxane structure in a value within a range of 35 to 60 parts by weight with respect to 100 parts by weight as a whole of all components other than the solvent used in the photoreceptor layer. When the total amount of is 100 mol%, the content ratio of the unit having a siloxane structure is set to a value in the range of 2 to 20 mol%, and the contact angle of pure water to the polycarbonate resin having a siloxane structure (measurement temperature: 25 ° C.) and a value within the range of ninety-eight to one hundred twenty °, as a hole transporting agent, a compound having a triphenylamine skeleton containing stilbene structure, polycarbonate having a siloxane structure To Boneto 100 parts by weight of the resin includes a value within a range of 30 to 60 parts by weight, compounds having a triphenylamine skeleton containing stilbene structure, the contact angle with respect to the resin dispersion film (measuring temperature: 25 ° C.) is 90 It is a compound having a value within the range of 120 °, the contact angle of pure water with respect to the photoreceptor layer (measurement temperature: 25 ° C.) is set to a value within the range of 102 to 110 , and the thickness of the photoreceptor layer is A single-layer type electrophotographic photosensitive member characterized by having a value within a range of 25 to 50 μm .

1. Basic Configuration (1) Structure As shown in FIG. 1A, the single-layer type photoreceptor 10 has a single photoreceptor layer 14 provided on a substrate 12.
In addition, the photoreceptor layer includes a binder resin, a hole transport agent, and a charge generator, and further includes an additive such as an electron transport agent, a leveling agent, or a silyl group-containing compound as necessary. be able to.

Further, the obtained single-layer type photoreceptor includes a polycarbonate resin having a specific siloxane structure, and the contact angle of pure water with respect to the photoreceptor layer is a value within a range of 102 to 110 °. This is characterized in that it is possible to suppress the occurrence of black spots and consequently black spots.
Furthermore, when an electron transport agent is included in the photoreceptor layer of a single-layer type photoreceptor, electrons are efficiently exchanged between the charge generator and the hole transport agent, and the sensitivity and the like are more stable. The tendency to do is seen.

(2) Binder Resin (2) -1 Type The binder resin includes a polycarbonate resin having a siloxane structure.
This is because the polycarbonate resin having such a structure not only facilitates the adjustment of the contact angle in the photoreceptor layer, but also provides excellent durability.

Moreover, when the whole polycarbonate resin which has a siloxane structure is 100 mol%, the content rate of the unit which has a siloxane structure shall be a value within the range of 2-20 mol%.
This is because by including a predetermined amount of the polycarbonate resin having such a structure, the contact angle in the photoreceptor layer can be easily adjusted, and further excellent durability can be obtained.
In addition, the repeating number of polycarbonate resin which has a siloxane structure represented by Formula (6) mentioned later represents the molar ratio of a copolymerization component, and represents that the molar ratio of each structural unit is 95: 5. Yes. Therefore, when the whole resin represented by Formula (6) is 100 mol%, the content ratio of the unit having a siloxane structure is 5 mol%. The molar ratio can be calculated by, for example, a nuclear magnetic resonance analyzer (NMR).

The polycarbonate resin having a siloxane structure preferably has a specific siloxane structure represented by the following structural formula (5).

(2) -2 Abundance ratio In addition, the polycarbonate resin having a specific siloxane structure is present non-uniformly on the surface of the photoreceptor layer, that is, more than the interior and back surface of the photoreceptor layer. It is preferable.
This is because the polycarbonate resin having a specific siloxane structure is unevenly present on the surface of the photoreceptor layer, so that excellent filming characteristics and durability can be obtained even in a relatively small amount. This is because it can be obtained.
Whether or not a polycarbonate resin having a specific siloxane structure is present non-uniformly may be calculated by NMR or FT-IR chart and compared, or elemental analysis by XPM or the like is performed. It is also possible.

(2) -3 Specific example Moreover, polycarbonate resin (Resin-AB) of following Structural formula (6)-(7) is mentioned as polycarbonate resin which has a specific siloxane structure used for this invention.

  In the present invention, various binder resins conventionally used for the photoreceptor layer can be used in combination. For example, styrene-butadiene copolymer, styrene-acrylonitrile copolymer, styrene-maleic acid copolymer, acrylic copolymer, styrene-acrylic acid copolymer, polyethylene resin, ethylene-vinyl acetate copolymer, chlorination Polyethylene resin, polyvinyl chloride resin, polypropylene resin, ionomer resin, vinyl chloride-vinyl acetate copolymer, polyester resin, alkyd resin, polyamide resin, polyurethane resin, polycarbonate resin, polyarylate resin, polysulfone resin, diallyl phthalate resin, ketone Thermoplastic resins such as resin, polyvinyl butyral resin, polyether resin, polyester resin; silicone resin, epoxy resin, phenol resin, urea resin, melamine resin, other crosslinkable thermosetting resins; epoxy acrylic Over bets, urethane - alone or in combinations of two or more such photocurable resin such as acrylate.

(2) -4 Contact angle to pure water A contact angle (measurement temperature condition: 25 ° C.) of a polycarbonate resin having a specific siloxane structure to pure water is a value within a range of 98 to 120 ° .
The reason for this is that by including the polycarbonate resin for the single-layer electrophotographic photosensitive member, it becomes easy to adjust the contact angle of pure water with respect to the photosensitive member layer, and paper dust, silica and the like are added to the photosensitive member layer. This is because it is difficult to adhere, and the generation of black spots and black streaks can be suppressed during image formation. That is, even when a highly polar hole transporting agent is used for a single-layer electrophotographic photosensitive member, it can maintain the function of suppressing the occurrence of filming, and a clear image without black spots and black streaks can be obtained. It can be provided over a long period of time. In addition, if the polycarbonate resin has a predetermined contact angle, it is excellent not only in transparency and heat resistance, but also excellent in mechanical properties and compatibility with a hole transport agent, and also excellent in durability. This is because a single-layer electrophotographic photosensitive member can be provided.
That is, when the contact angle with respect to the pure water is less than 98 °, it may be difficult to adjust the contact angle in the photoreceptor layer.
The contact angle of the polycarbonate resin with respect to pure water is as shown in Example 1, after applying a THF solution having a resin concentration of 25% on an aluminum substrate by a dip coating method, and then at 100 ° C. for 40 minutes. A resin film having a film thickness of 25 μm obtained by drying with hot air can be targeted. And the contact angle with respect to the pure water of this resin film can be measured by a droplet method using a contact angle meter (Kyowa Interface Science Co., Ltd. make, FACE-CONACT-ANGLE METER).

Here, with reference to FIG. 2, the relationship between the contact angle of pure water with respect to the polycarbonate resin which has a specific siloxane structure and the number of black spots generated per unit area will be described. The horizontal axis of FIG. 2 shows the contact angle (°) on the surface of the polycarbonate resin film having a specific siloxane structure, and the vertical axis shows the number of black spots generated per A4 paper (pieces / A4 paper). ) Is shown.
As can be easily understood from FIG. 2, when the contact angle with respect to the polycarbonate resin having a specific siloxane structure is 98 ° or more, the number of black spots generated is 130 (pieces / A4 paper) or less, which is efficiently reduced. I understand that Therefore, by controlling the contact angle of the binder resin to a value equal to or higher than a predetermined value, it is considered that as a result, the generation of black spots can be efficiently reduced even when a highly polar hole transport agent is used. .

In addition, when the contact angle with respect to the polycarbonate resin which has a specific siloxane structure becomes large too much, the kind etc. of the polycarbonate resin which has the specific siloxane structure which can be selected may become too few.
Therefore, it is more preferable that the contact angle of pure water with respect to the polycarbonate resin having a specific siloxane structure is a value within the range of 98 to 120 °, and a value within the range of 103 to 110 °.

(2) -5 Content Ratio When the total amount of all components other than the solvent used in the single-layer type photoreceptor layer is 100 parts by weight, the content ratio of the polycarbonate resin having a specific siloxane structure is 35-60. The value is within the range of parts by weight.
The reason for this is that when the content ratio of the polycarbonate resin having the specific siloxane structure is less than 35 parts by weight, it may be difficult to adjust the contact angle in the photoreceptor layer. This is because if the content of the polycarbonate resin having a structure exceeds 60 parts by weight, the adhesion between the photoreceptor layer and the substrate may be extremely reduced.
Therefore, the content ratio of the polycarbonate resin having a specific siloxane structure is set to a value in the range of 35 to 60 parts by weight when the total amount of the binder resin used in the single-layer type photoreceptor layer is 100 parts by weight. Is more preferable, and a value within the range of 40 to 55 parts by weight is even more preferable.

(2) -6 Viscosity average molecular weight Moreover, the viscosity average molecular weight of the polycarbonate resin having a specific siloxane structure used for the single-layer type photoreceptor layer of the present invention is set to a value within the range of 10,000 to 60,000. Is preferred.
This is because a photoreceptor having excellent durability can be provided by using a polycarbonate resin having a specific siloxane structure having such a viscosity average molecular weight.
In addition, the viscosity average molecular weight (M) of the polycarbonate resin having a specific siloxane structure is determined by obtaining the intrinsic viscosity [η] with an Ostwald viscometer, and [η] = 1.23 × 10 ⁻⁴ M ^0.83 according to the Schnell equation. Calculated from [Η] can be measured from a polycarbonate resin solution obtained by dissolving a polycarbonate resin at 20 ° C. using a methylene chloride solution as a solvent so that the concentration (C) is 6.0 g / dm ^3. it can.

(3) Hole transport agent (3) -1 contact angle Moreover, the contact angle with respect to the pure water in the resin dispersion film | membrane of a hole transport agent is a value within the range of 90-120 degrees, It is characterized by the above-mentioned .
The reason for this is that by using the hole transport agent applied to the single-layer electrophotographic photosensitive member of the present invention, the adhesion of silica and paper dust can be effectively prevented, and the generation of black spots can be more efficiently reduced. This is because it can.
Therefore, it is more preferable that the contact angle with respect to pure water in the resin dispersion film of the hole transport agent is in the range of 95 to 120 °, and more preferably in the range of 100 to 110 °.
In addition, the contact angle with respect to the pure water in the resin-dispersed film of the hole transport agent can be measured by the method shown in Example 1. That is, 43 parts by weight of a hole transport agent, 100 parts by weight of Z-type polycarbonate resin (TS2020, manufactured by Teijin Chemicals) having a viscosity average molecular weight of 20,000, and dimethylpolysiloxane (KF-90, 50 cps, Shin-Etsu Chemical) 0.1 parts by weight and 800 parts by weight of tetrahydrofuran were mixed and dispersed, and the resulting solution was applied onto an aluminum substrate by dip coating, and dried with hot air at 100 ° C. for 40 minutes. Thus, a hole transport agent resin dispersion film having a film thickness of 25 μm is obtained. Subsequently, the contact angle (measurement temperature: 25 ° C.) of the hole transport agent resin dispersion film with pure water was measured by a droplet method using a contact angle meter (FACE-CONACT-ANGLE METER, manufactured by Kyowa Interface Science Co., Ltd.). Can be measured.

(3) -2 types
In addition, the hole transporting agent used in the present invention includes a compound having a triphenylamine skeleton including a stilbene structure.
This is because a hole transporting agent having such a structure is excellent in sensitivity characteristics and can easily adjust the contact angle, so that the occurrence of filming can be effectively suppressed.
In addition, the hole transporting agent having such a structure is more compatible with the binder resin, and thus can be excellent in durability and sensitivity characteristics.

Moreover, the hole transport agent suitable for the single layer type electrophotographic photoreceptor of the present invention is specifically a compound represented by the following formulas (10), (12), (14) (HTM-A, C, E) is preferred .

  In the present invention, conventionally known hole transport materials, oxadiazole compounds such as 2,5-di (4-methylaminophenyl) -1,3,4-oxadiazole, 9- (4- Styryl compounds such as diethylaminostyryl) anthracene, carbazole compounds such as polyvinylcarbazole, organic polysilane compounds, pyrazoline compounds such as 1-phenyl-3- (p-dimethylaminophenyl) pyrazoline, hydrazone compounds, triphenylamine compounds Compounds, indole compounds, oxazole compounds, isoxazole compounds, thiazole compounds, thiadiazole compounds, imidazole compounds, pyrazole compounds, triazole compounds and other nitrogen-containing cyclic compounds, condensed polycyclic compounds, etc. Single or a combination of two or more It is.

(3) -3 addition amount It is preferable to determine the addition amount of the hole transport agent in consideration of the addition amount of the binder resin. More specifically, the amount of the hole transport agent added is preferably set to a value in the range of 30 to 60 parts by weight with respect to 100 parts by weight of the binder resin.
The reason for this is that when the added amount of the hole transport agent is less than 30 parts by weight, the sensitivity is lowered and a practical problem may occur. On the other hand, when the added amount of the hole transport agent exceeds 60 parts by weight, the hole transport agent is likely to be crystallized, and an appropriate film as a photoreceptor may not be formed.

(4) Electron Transfer Agent (4) -1 Type It is also preferable that the single layer type electrophotographic photosensitive member of the present invention further contains an electron transfer agent. As such an electron transport agent, a compound containing a diphenoquinone derivative and a pyrene derivative is preferable. The reason for this is that the use of such a compound having excellent electron acceptability as an electron transport agent results in excellent compatibility with the charge generating agent. This is because a photographic photoreceptor can be provided.

(4) -2 Specific Examples Specific examples of these electron transfer agents include compounds (ETM-A to ETM-H) represented by the following formulas (22) to (29).

Further, as the electron transport agent used in the present invention, it is also preferable to use another conventionally known electron transport agent in combination with the photoreceptor layer.
For example, in addition to benzoquinone derivatives, anthraquinone derivatives, malononitrile derivatives, thiopyran derivatives, trinitrothioxanthone derivatives, 3,4,5,7-tetranitro-9-fluorenone derivatives, dinitroanthracene derivatives, dinitroacridine derivatives, nitroantharaquinone derivatives, Dinitroanthraquinone derivative, tetracyanoethylene, 2,4,8-trinitrothioxanthone, dinitrobenzene, dinitroanthracene, dinitroacridine, nitroanthraquinone, dinitroanthraquinone, succinic anhydride, maleic anhydride, dibromomaleic anhydride, etc. A combination of two or more types can be mentioned.
Of these electron transfer agents, compounds having an electron mobility of 1.0 × 10 ⁻⁸ cm ² / V / sec or more at an electric field strength of 5 × 10 ⁵ v / cm are more preferable.

(4) -3 Addition The addition amount of the electron transfer agent is preferably set to a value within the range of 10 to 100 parts by weight with respect to 100 parts by weight of the binder resin.
The reason for this is that when the added amount of the plurality of electron transfer agents is less than 10 parts by weight, the sensitivity is lowered and a practical problem may occur. On the other hand, when the added amount of the plurality of electron transfer agents exceeds 100 parts by weight, the electron transfer agent is likely to be crystallized, and an appropriate film as a photoreceptor may not be formed.
Therefore, it is more preferable to set the addition amount of the electron transfer agent to a value within the range of 20 to 80 parts by weight.

In addition, when determining the addition amount of an electron transport agent, it is preferable to consider the addition amount of a hole transport agent. More specifically, the addition ratio (total ETM / total HTM) of the electron transport agent (total ETM) is a value within the range of 0.25 to 1.3 with respect to the hole transport agent (total HTM). It is preferable to do.
This is because if the ratio of all ETMs / all HTMs is outside this range, the sensitivity is lowered, which may cause practical problems.
Therefore, it is more preferable that the ratio of the total ETM / total HTM is set to a value within the range of 0.5 to 1.25.

(5) Charge generator (5) -1 type In addition, as the charge generator used in the monolayer type electrophotographic photoreceptor of the present invention, metal-free phthalocyanine (τ type or X type), titanyl phthalocyanine (α type) Or at least one compound selected from the group consisting of hydroxygallium phthalocyanine (type V) and chlorogallium phthalocyanine (type II).
The reason for this is to provide an electrophotographic photosensitive member that is more excellent in sensitivity characteristics, electrical characteristics, stability, etc. when a hole transporting agent and an electron transporting agent are used in combination by specifying the type of charge generating agent. It is because it can do.

(5) -2 Specific Example Further, among these charge generators, specifically, phthalocyanine pigments (CGM-A to CGM-D) represented by the following formulas (30) to (33) are used. Is more preferable.

  It is also preferable to use a conventionally known charge generating agent alone or in combination. Such charge generators include phthalocyanine pigments such as oxo titanyl phthalocyanine, perylene pigments, bisazo pigments, diketopyrrolopyrrole pigments, metal-free naphthalocyanine pigments, metal naphthalocyanine pigments, squaraine pigments, trisazo pigments, indigo Organic photoconductors such as pigments, azulenium pigments, cyanine pigments, pyrylium pigments, ansanthrone pigments, triphenylmethane pigments, selenium pigments, toluidine pigments, pyrazoline pigments, quinacridone pigments, selenium, selenium-tellurium, selenium- One kind of inorganic photoconductive agent such as arsenic, cadmium sulfide, or amorphous silicon, or a mixture of two or more kinds may be used.

(5) -3 Addition amount The addition amount 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 added amount of the plurality of charge generating agents is less than 0.2 parts by weight, the effect of increasing the quantum yield becomes insufficient, and the sensitivity, electrical characteristics, stability, etc. of the electrophotographic photosensitive member are reduced. This is because it cannot be improved. On the other hand, when the added amount of the plurality of charge generating agents exceeds 40 parts by weight, there is an effect of increasing the extinction coefficient for light having a wavelength in the red region, near infrared region, or infrared region in visible light. This is because the sensitivity characteristics, electrical characteristics, stability, and the like of the photoconductor may not be improved.
Therefore, it is more preferable to set the addition amount of the charge generating agent to a value within the range of 0.5 to 20 parts by weight.

(6) Additive The photoreceptor layer preferably contains at least one compound of the group consisting of the compounds represented by the general formulas (1) to (4) as an additive.
The reason for this is that by using a compound having such a structure as an additive, it is possible to suppress the occurrence of cracks on the surface of the photoreceptor due to the adhesion of contaminants, and as a result, the occurrence of black spots and fog in the image is suppressed. This is because it can be prevented.
That is, the single-layer electrophotographic photosensitive member according to the present invention uses a polycarbonate having a specific siloxane structure as a binder resin in the photosensitive member, and further, the contact angle of pure water with respect to the photosensitive layer is a value within a predetermined range. Therefore, problems such as black spots caused by filming are sufficiently solved. Therefore, the image characteristics can be further improved by further preventing the occurrence of black spots or fog caused by cracks.

(In General Formula (1), R < ¹ > -R < ¹⁰ > is an independent substituent, respectively, a hydrogen atom, a halogen atom, a substituted or unsubstituted C1-C12 alkyl group, a substituted or unsubstituted carbon number 1 -12 alkoxy group, substituted or unsubstituted aryl group having 6 to 30 carbon atoms, substituted or unsubstituted aralkyl group having 6 to 30 carbon atoms, substituted or unsubstituted cycloalkyl group having 3 to 12 carbon atoms, hydroxyl Group, cyano group, nitro group, amino group or halogenated alkyl group.)

(R ^{11 to} R ¹³ in the general formula (2) are each an independent substituent, and are a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted carbon number of 1 -12 alkoxy group, substituted or unsubstituted aryl group having 6 to 30 carbon atoms, substituted or unsubstituted aralkyl group having 6 to 30 carbon atoms, substituted or unsubstituted cycloalkyl group having 3 to 12 carbon atoms, hydroxyl Group, cyano group, nitro group, amino group or halogenated alkyl group.)

(Formula (3) R ¹⁴ ~R ¹⁵ in are independent substituents, a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted C 1 -12 alkoxy group, substituted or unsubstituted aryl group having 6 to 30 carbon atoms, substituted or unsubstituted aralkyl group having 6 to 30 carbon atoms, substituted or unsubstituted cycloalkyl group having 3 to 12 carbon atoms, hydroxyl Group, cyano group, nitro group, amino group or halogenated alkyl group.)

(R ^{16 to} R ²² in the general formula (4) are each an independent substituent, a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group having 1 to 12 carbon atoms, a substituted or unsubstituted carbon number of 1 -12 alkoxy group, substituted or unsubstituted aryl group having 6 to 30 carbon atoms, substituted or unsubstituted aralkyl group having 6 to 30 carbon atoms, substituted or unsubstituted cycloalkyl group having 3 to 12 carbon atoms, hydroxyl Group, cyano group, nitro group, amino group or halogenated alkyl group.)

  Specific additives include compounds represented by the following formulas (34) to (48) (additive-A to additive-N and additive-O-1 to additive-O-17). Is preferably used.

Here, the crack generation mechanism and the generation suppression mechanism described above will be described.
First, when a contaminant adheres to the surface of the photoreceptor, the monomer component in the photoreceptor layer is eluted from the photoreceptor layer. As a result, pores are generated in the binder resin constituting the photoreceptor layer. In addition, since local stress is likely to be generated in the hole portion, a crack as mechanical damage is generated on the surface of the photoreceptor layer.
On the other hand, since the compounds represented by the above general formulas (1) to (4) are used as additives, the local stress generated in the void portion generated by the elution of the monomer component can be released. The occurrence of cracks can be suppressed.

Moreover, it is preferable to make content of this additive into the value within the range of 1.5 to 15 weight% with respect to the whole quantity of a photoreceptor layer.
The reason for this is that when the content is less than 1.5% by weight, the stress relaxation action as described above cannot be sufficiently exhibited, and crack generation cannot be sufficiently prevented. . On the other hand, when the content exceeds 15% by weight, the glass transition point of the photoreceptor layer is lowered, and the wear resistance may be lowered. Moreover, it is because the dispersibility in binder resin falls and the case where it crystallizes is seen.
That is, when the content is set to a value within such a range, it becomes possible to obtain the crack resistance of the photoreceptor layer without increasing the molecular weight of the binder resin, and the productivity is excellent. Photoconductor.
Therefore, the content is more preferably set to a value within the range of 2 to 12% by weight, and more preferably set to a value within the range of 3 to 10% by weight with respect to the total amount of the photoreceptor layer.

(7) Other Additives In addition to the above-described components, various other conventionally known additives such as antioxidants and radical scavengers are included in the photoreceptor layer within the range that does not adversely affect the electrophotographic characteristics. Deterioration inhibitors such as singlet quenchers and ultraviolet absorbers, softeners, plasticizers, surface modifiers, extenders, thickeners, dispersion stabilizers, waxes, acceptors, donors, and the like can be blended. In order to improve the sensitivity of the photoreceptor layer, known sensitizers such as terphenyl, halonaphthoquinones, and acenaphthylene may be used in combination with the charge generator.

(8) Contact angle Further, the contact angle of pure water with respect to the photoreceptor layer (measurement temperature: 25 ° C.) is set to a value in the range of 102 to 110 °.
This is because, for the purpose of improving the sensitivity, the black spot is increased even if the amount of the hole transport agent is increased, the polarity of the hole transport agent is increased, or the photosensitive drum is rotated at a high speed. This is because it is possible to provide a single-layer type electrophotographic photosensitive member with less generation.

Here, the relationship between the contact angle of the electrophotographic photosensitive member and the number of black spots per unit area will be described with reference to FIG. The horizontal axis in FIG. 3 shows the contact angle (°) on the surface of the electrophotographic photosensitive member, and the vertical axis shows the number of black spots generated per A4 paper (pieces / A4 paper). It is shown.
As can be easily understood from FIG. 3, when the contact angle of the electrophotographic photosensitive member with respect to the photosensitive layer becomes a value of 102 ° or more, the number of black spots generated is 90 (pieces / A4 paper) or less, which is efficiently reduced. I understand that Therefore, by controlling the contact angle of the binder resin to a value equal to or higher than a predetermined value, it is considered that as a result, the generation of black spots can be efficiently reduced even when a highly polar hole transport agent is used. .

If the contact angle of the electrophotographic photoreceptor with respect to the photoreceptor layer is excessively large, the types of polycarbonate resin having a specific selectable siloxane structure may be excessively decreased.
Therefore, the contact angle of pure water with respect to the photoreceptor layer is more preferably set to a value within the range of 103 to 110 °.

(9) Structure (9) -1 Photoreceptor Layer Further, the thickness of the photoreceptor layer in the single-layer type photoreceptor is a value in the range of 25 to 50 μm .

(9) -2 Substrate As the substrate on which such a photoreceptor layer is formed, various materials can be used, for example, iron, aluminum, copper, tin, platinum, silver, vanadium, molybdenum, Chromium, cadmium, titanium, nickel, palladium, indium, stainless steel, brass and other metals, plastic materials on which the above metals are deposited or laminated, glass coated with aluminum iodide, tin oxide, indium oxide, etc., or Examples thereof include a plastic material in which conductive fine particles such as carbon black are dispersed.
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. Further, the surface of the substrate may be subjected to an electrically insulating oxidation treatment or the like.
Further, the substrate preferably has a sufficient mechanical strength when used. Further, when forming a photoreceptor layer, a binder resin, a hole transport agent, an electron transport agent, and a charge generator, together with an appropriate solvent, for example, a roll mill, a ball mill, an attritor, a paint shaker, What is necessary is just to apply | coat and dry after carrying out dispersion | distribution mixing using a sonic disperser.
Further, regarding the configuration of the single-layer type photoreceptor, as shown in FIG. 1B, a barrier layer 16 is formed between the substrate 12 and the photoreceptor layer 14 within a range that does not impair the characteristics of the photoreceptor. The single-layer type photoreceptor 10 ′ may be used.

(9) -3 Drum Diameter The drum diameter (base diameter) of the photoconductor is preferably set to a value of 30 mm or less.
The reason for this is that in the case of the single-layer electrophotographic photosensitive member according to the present invention, even when the drum diameter is set to a value of 30 mm or less, the occurrence of black spots or the like due to filming on the surface of the photosensitive member is prevented. This is because the size of the image forming apparatus can be reduced.
Specifically, by setting the drum diameter to a value of 30 mm or less, the number of rotations of the photoconductor for forming the same number of images is increased as compared with the case where a photoconductor having a larger drum diameter is used. become. As a result, filming on the surface of the photoreceptor is more likely to occur.
However, even when the drum diameter is set to a value of 30 mm or less, the single-layer electrophotographic photosensitive member according to the present invention includes a polycarbonate resin having a specific siloxane structure as a binder resin, Since the contact angle of pure water is set to a value greater than or equal to a predetermined value, the occurrence of such filming can be prevented.

Further, by setting the drum diameter to a value of 30 mm or less, the curvature of the photoconductor layer increases, and as a result, the stress applied to the photoconductor layer increases and cracks are likely to occur.
However, even when the drum diameter is 30 mm or less, such cracks are generated by adding the compounds represented by the general formulas (1) to (4) to the photosensitive layer. Can be prevented.
Accordingly, the drum diameter is more preferably set to a value within the range of 10 to 28 mm, and further preferably set to a value within the range of 15 to 25 mm.

[Second Embodiment]
The second embodiment includes the single-layer electrophotographic photosensitive member of the first embodiment (hereinafter sometimes simply referred to as a photosensitive member), and a charging step and exposure around the electrophotographic photosensitive member. An image forming apparatus characterized in that an image forming is performed by arranging a process, a developing process, and a transfer process.

In carrying out the image forming method of the second embodiment, a copying machine 30 which is an image forming apparatus as shown in FIG. 4 can be preferably used. 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.
Note that the electrophotographic photosensitive member described in the first embodiment is preferably used as the photosensitive drum 41.

  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.

In the image forming apparatus of the present invention, it is preferable that the developing process is a simultaneous development cleaning system. In other words, the simultaneous development cleaning method is a cleaner in which the cleaning device is omitted, and the transfer residual toner on the photosensitive member after transfer is recovered and reused in the developing step of the photosensitive member by the developing device as the developing step means. It is a transfer system image forming apparatus of a less system.
Usually, in such an image forming apparatus of a cleanerless system, it is difficult to completely collect paper dust and silica, and there is a case where paper dust and silica adhere to the photosensitive member in a relatively large amount. The problem that black streaks are likely to occur easily occurs. However, according to the image forming apparatus of the present invention, since a single layer type electrophotographic photosensitive member having a predetermined contact angle is mounted, filming can be effectively generated even if the development process is a simultaneous development cleaning method. Can be prevented. Therefore, it is possible to provide an image forming apparatus that can be reduced in size, weight, and cost.

In the image forming apparatus of the present invention, it is preferable that the drum rotation speed of the photoreceptor is 100 mm / sec or more.
By setting such a drum rotation speed, the load on the paper in the transport path is increased, so that paper dust is easily generated. For this reason, there is a problem that paper dust adheres to the photoreceptor more and black spots and black streaks are easily generated in the image. However, since such an image forming apparatus is equipped with a single-layer type electrophotographic photosensitive member having a predetermined contact angle, filming is effective even when the drum rotating speed of the photosensitive member is 100 mm / sec or more. Therefore, the occurrence of black spots or the like in the image can be suppressed. Therefore, it is possible to provide an image forming apparatus capable of speeding up image formation.

Here, the relationship between the drum rotation speed of the photosensitive member and the number of black spots will be described with reference to FIG. The horizontal axis of FIG. 5 shows the drum rotation speed (mm / sec) of the photoconductor, and the vertical axis shows the number of black spots generated per A4 paper (pieces / A4 paper). A to C in the figure are characteristic curves corresponding to the photoreceptors of Examples 1 and 3 and Comparative Example 1, respectively.
From FIG. 5, when the drum rotation speed of the photoconductor is 60 (mm / sec), the number of black spots attached to the photoconductors A to C is almost the same, but the drum rotation speed of the photoconductor is 100 (mm / sec). In the above case, it can be seen that there is a large difference in the number of black spots attached to the photoconductors A to C. It can be seen that the photosensitive member C has an increased drum rotation speed and increased the number of black spots, and the number of black spots increases even when the drum rotation speed is 100 (mm / sec) or more. On the other hand, the photoconductors A and B have almost no change in the number of black spots even when the drum rotation speed is increased, or the increase in the number of black spots when the drum rotation speed is 100 (mm / sec) or more. Recognize. That is, it can be seen that the A and B photoconductors have a relatively low number of black spots even when the drum rotation speed is 100 (mm / sec) or more.
Therefore, it is more preferable that the drum rotation speed of the photoconductor is a value in the range of 100 to 200 mm / sec. The reason for this is that if the drum rotation speed is 200 mm / sec or more, the load on the paper is too great, which may cause a problem in paper conveyance and the like.

[Example 1]
1. Preparation of electrophotographic photoreceptor In the container, 4 parts by weight of X-type metal-free phthalocyanine (CGM-A) represented by the formula (30) as a charge generating agent and formula (10) as a hole transporting agent are represented. 50 parts by weight of the stilbene derivative (HTM-A), 30 parts by weight of the naphthoquinone derivative (ETM-A) represented by the formula (22) as an electron transport agent, and the formula (6) as a binder resin. 100 parts by weight of a polycarbonate resin having a viscosity average molecular weight of 20,000 (Resin-A) 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 a single-layer type photoreceptor layer. The obtained coating solution was applied on a substrate (aluminum tube) having a diameter of 30 mm by dip coating, and dried with hot air under conditions of 100 ° C. for 40 minutes, and a single-layer type photoreceptor layer having a thickness of 25 μm. An electrophotographic photoreceptor having the following was obtained.

2. Evaluation of Electrophotographic Photoreceptor and Resin Film (1) Contact angle measurement of polycarbonate resin having specific siloxane structure A resin film was formed and the contact angle of polycarbonate resin having a specific siloxane structure was measured. That is, 25 parts by weight of a resin (Reisn-A) having a viscosity average molecular weight of 20,000 represented by the formula (6) and 75 parts by weight of tetrahydrofuran were mixed for 24 hours to prepare a coating solution. The obtained coating solution was applied on an aluminum base tube having a diameter of 30 mm by dip coating, and dried with hot air at 100 ° C. for 40 minutes to obtain a resin film with a thickness of 25 μm. The contact angle (measurement temperature: 25 ° C.) of the resin film with respect to pure water was measured by a droplet method using a contact angle meter (FACE-CONACT-ANGLE METER, manufactured by Kyowa Interface Science Co., Ltd.). The obtained results are shown in Table 1.

(2) Measurement of contact angle of hole transport agent Next, a resin film made of the hole transport agent was prepared, and the contact angle was measured. That is, 43 parts by weight of the compound represented by formula (10) (HTM-A), 100 parts by weight of Z-type polycarbonate resin (TS2020 made by Teijin Chemicals) having a viscosity average molecular weight of 20,000, and dimethylpolysiloxane ( 0.1 parts by weight of KF-90, 50 cps (manufactured by Shin-Etsu Chemical Co., Ltd.) and 800 parts by weight of tetrahydrofuran were mixed for 24 hours to prepare a hole transfer agent resin dispersion solution. The obtained solution was applied on an aluminum base tube by a dip coating method and dried with hot air at 100 ° C. for 40 minutes to obtain a hole transport agent resin dispersion film having a film thickness of 25 μm. The contact angle (measurement temperature: 25 ° C.) of the hole transport agent resin dispersion film with pure water was measured by a droplet method using a contact angle meter (FACE-CONTACT-ANGLE METER, manufactured by Kyowa Interface Science Co., Ltd.). . The obtained results are shown in Table 1.

(3) Measurement of contact angle in the photoreceptor layer of the electrophotographic photoreceptor The contact angle (measurement temperature: 25 ° C.) of the photoreceptor layer of the electrophotographic photoreceptor obtained in the above with respect to pure water was measured by a droplet method using a contact angle meter (FACE-CONTACT-ANGLE METER, manufactured by Kyowa Interface Science Co., Ltd.). Measured with The obtained results are shown in Table 1.

(4) Measurement of the number of black spots generated Next, the obtained electrophotographic photosensitive member was mounted on a Kyocera Mita printer Actico 40 remodeling machine with a drum rotation speed of 140 mm / sec, and A4 under an environmental condition of 40 ° C. and 90% Rh. 5000 sheets of paper (Fuji Xerox quality PPC paper) were continuously printed. Thereafter, after leaving for 6 hours, a blank A4 paper document was printed, and the number of black spots generated on the A4 paper was counted and evaluated according to the following criteria.
A: Less than 50 black spots occur per A4 paper.
A: The number of black spots generated per A4 paper is 50 or more and less than 80.
Δ: The number of black spots generated per A4 paper is 80 or more and less than 130.
X: 130 or more black spots are generated per A4 sheet.

[Example 2 and Reference Examples 3 to 4]
In Example 2 and Reference Examples 3 to 4, as shown in Table 1, the viscosity represented by the formulas (7) to (9) instead of the binder resin (Reisn-A) used in Example 1 was used. A single layer type photoreceptor was prepared and evaluated in the same manner as in Example 1 except that binder resins (Resin-BD) each having an average molecular weight of 20,000 were added. The results obtained are shown in Table 1.

[Examples 5-6 and Reference Examples 7-8]
In Examples 5-6 and Reference Examples 7-8, as shown in Table 1, instead of the hole transport agent (HTM-A) used in Examples 1-2 and Reference Examples 3-4, the formula ( A single layer type photoreceptor was prepared and evaluated in the same manner as in Examples 1-2 and Reference Examples 3-4 except that the hole transport agent (HTM-E) represented by 14) was used. The results obtained are shown in Table 1.

[ Reference Examples 9-12 ]
In Reference Examples 9-12 , as shown in Table 1, it is represented by Formula (11) instead of the hole transport agent (HTM-A) used in Examples 1-2 and Reference Examples 3-4. A single layer type photoreceptor was prepared and evaluated in the same manner as in Examples 1 and 2 and Reference Examples 3 and 4 except that the hole transport agent (HTM-B) was used. The results obtained are shown in Table 1.

[Comparative Examples 1-2]
In Comparative Examples 1-2, as shown in Table 1, instead of the binder resin (Reisn-A) used in Example 1, the viscosity average molecular weight represented by the following formulas (49)-(50) A single layer type photoreceptor was prepared and evaluated in the same manner as in Example 1 except that 20,000 binder resins were added. The results obtained are shown in Table 1.

[Comparative Examples 3 to 4]
In Comparative Examples 3 to 4, as shown in Table 1, instead of the hole transport agent (HTM-A) used in Example 1, the hole transport agent (HTM-E) represented by the formula (14) is used. ), And instead of the binder resin (Resin-A), the binder resins (Resin-E to F) whose viscosity average molecular weights represented by the formulas (49) to (50) are 20,000, respectively. A single-layer type photoreceptor was prepared and evaluated in the same manner as in Example 1 except that each was added. The results obtained are shown in Table 1.

[Example 13]
In Example 13, as shown in Table 2, the obtained coating solution for the photoreceptor layer was applied on an aluminum base tube having a diameter of 24 mm instead of the aluminum base tube having a diameter of 30 mm used in Example 1. In the same manner as in Example 1, a single layer type electrophotographic photosensitive member was prepared and evaluated.

[Example 14 and Reference Examples 15 to 16]
In Example 14 and Reference Examples 15 to 16, as shown in Table 2, the viscosity represented by the formulas (7) to (9) instead of the binder resin (Reisn-A) used in Example 13 was used. A single-layer photoreceptor was prepared and evaluated in the same manner as in Example 13 except that binder resins (Resin-BD) each having an average molecular weight of 20,000 were added. The results obtained are shown in Table 2.

[Examples 17 to 18 and Reference Examples 19 to 20]
In Examples 17 to 18 and Reference Examples 19 to 20, as shown in Table 2, instead of the hole transport agent (HTM-A) used in Examples 13 to 14 and Reference Examples 15 to 16, the formula ( A single layer type photoreceptor was prepared and evaluated in the same manner as in Examples 13 to 14 and Reference Examples 15 to 16, except that the hole transport agent (HTM-E) represented by 14) was used. The results obtained are shown in Table 2.

[ Reference Examples 21 to 24 ]
In Reference Examples 21-24 , as shown in Table 2, it is represented by Formula (11) instead of the hole transport agent (HTM-A) used in Examples 13-14 and Reference Examples 15-16. A single layer type photoreceptor was prepared and evaluated in the same manner as in Examples 13 to 14 and Reference Examples 15 to 16 except that the hole transport agent (HTM-B) was used. The results obtained are shown in Table 2.

[Comparative Examples 5-6]
In Comparative Examples 5 to 6, as shown in Table 2, instead of the binder resin (Reisn-A) used in Example 13, the viscosity average molecular weights represented by the formulas (49) to (50) are respectively A single-layer photoreceptor was prepared and evaluated in the same manner as in Example 13 except that 20,000 binder resins (Resin-E to F) were added. The results obtained are shown in Table 2.

[Comparative Examples 7-8]
In Comparative Examples 7 to 8, as shown in Table 2, instead of the hole transport agent (HTM-A) used in Example 13, the hole transport agent (HTM-E) represented by the formula (14) is used. ), And instead of the binder resin (Resin-A), the binder resins (Resin-E to F) whose viscosity average molecular weights represented by the formulas (49) to (50) are 20,000, respectively. A single-layer type photoreceptor was prepared and evaluated in the same manner as in Example 13 except that each was added. The results obtained are shown in Table 2.

[Example 25]
In Example 25, when preparing the coating solution for the photoreceptor layer, as shown in Table 3, instead of the hole transport agent (HTM-A) used in Example 1, the formula (14) was used. The represented hole transport agent (HTM-E) was used. Further, an additive (Additive-A) represented by the formula (34) was added so that the content was 1.5% by weight of the total amount of the photoreceptor layer. Other than that, a coating solution for the photoreceptor layer was prepared in the same manner as in Example 1.
In addition, the obtained coating solution was applied to a 24 mm diameter aluminum base tube instead of the 30 mm diameter aluminum base tube used in Example 1, and the single layer type electrophotographic photosensitive member was the same as in Example 1. Created the body.
In addition to the evaluation performed in Example 1, as the evaluation, crack growth rate measurement and wear resistance evaluation were performed. The evaluation method will be specifically shown below.

1. Contamination resistance evaluation and crack resistance evaluation With respect to the surface of the obtained photoreceptor, 30 g of oleic acid triglyceride, which has been separately found to behave in the same manner as sebum and finger oil considered as a contamination component derived from the human body, is provided. Is immersed for 20 hours (1200 min) at a temperature of 20 ° C. and a humidity of 60%, and after washing the photoreceptor with ethanol, the length of cracks is measured using an optical microscope, and the growth rate per unit time is determined. Calculated. Further, the crack resistance in the photoreceptor was evaluated from the crack growth rate according to the following criteria. Table 3 shows the obtained results.
A: The crack growth rate is a value less than 2 (mm / min).
○: The crack growth rate is a value of 2 (mm / min) or more and less than 4 (mm / min).
Δ: Crack growth rate is a value of 4 (mm / min) or more and less than 5 (mm / min).
X: The crack growth rate is a value of 5 (mm / min) or more.

2. Evaluation of member resistance The member resistance of the obtained photoreceptor layer was evaluated. That is, the photoconductor was mounted on a drum unit and left for 10 days at a temperature of 50 ° C. and a humidity of 80%. After being left, a gray image was output, and the streaks due to the press-contact marks of the members appearing on the image were evaluated according to the following criteria.
○: Generation of muscle is not confirmed.
Δ: Slight streaks occur.

[Examples 26 to 31]
In Examples 26 to 31, as shown in Table 3, a single-layer type photoconductor as in Example 25 except that the content of the additive (Additive-A) used in Example 25 was changed. Was created and evaluated. The results obtained are shown in Table 3.

[Examples 32-33]
In Examples 32-33, as shown in Table 3, instead of the hole transport agent (HTM-E) used in Example 25, the hole transport agent (HTM-A) represented by Formula (10) )It was used. Moreover, as shown in Table 3, the content of the additive (Additive-A) used in Example 25 was changed. Other than that, a single-layer type photoreceptor was prepared and evaluated in the same manner as in Example 25. The results obtained are shown in Table 3.

[Example 34]
In Example 34, as shown in Table 3, the binder resin (Resin-B) represented by the formula (7) was used instead of the binder resin (Resin-A) used in Example 25. . Further, instead of the additive (additive-A) used in Example 25, the additive (additive-G) represented by the formula (40) was 7.4% by weight of the total amount of the photoreceptor layer. A single-layer type photoreceptor was prepared and evaluated in the same manner as in Example 25 except that the above was added. The results obtained are shown in Table 3.

[Example 35, Reference Example 36 and Example 37]
In Example 35, Reference Example 36, and Example 37, as shown in Table 3, instead of the additive (Additive-A) used in Example 25, the formulas (39), (35), and The same as in Example 25 except that the additives (F), (B), and (E) represented by (38) were added so as to be 4.2% by weight of the total amount of the photoreceptor layer. A single layer type photoreceptor was prepared and evaluated. The results obtained are shown in Table 3.

[ Reference Example 38 ]
In Reference Example 38 , as shown in Table 3, instead of the hole transport agent (HTM-E) used in Example 25, the hole transport agent (HTM-B) represented by the formula (11) was used. A single-layer photoconductor was prepared and evaluated in the same manner as in Example 25 except that the content of the additive (additive-A) was 4.2% by weight of the total amount of the photoconductor layer. . The results obtained are shown in Table 3.

[Example 39]
In Example 27, as shown in Table 3, the content of the additive (Additive-A) in Example 25 was 1.6% by weight of the total amount of the photoreceptor layer, and the resulting photoreceptor layer was obtained. A single-layer type photoconductor was prepared in the same manner as in Example 25 except that the coating solution for coating was applied onto an aluminum tube having a diameter of 30 mm instead of the aluminum tube having a diameter of 24 mm used in Example 25. evaluated. The results obtained are shown in Table 3.

[Comparative Example 9]
In Comparative Example 9, as shown in Table 3, the binder resin (Resin-E) represented by the formula (49) was used instead of the binder resin (Resin-A) used in Example 25. A single-layer type photoconductor was prepared and evaluated in the same manner as in Example 25 except that the content of the additive (Additive-A) was 2.3% by weight of the total amount of the photoconductor layer. did. The results obtained are shown in Table 3.

[Comparative Example 10]
In Comparative Example 10, as shown in Table 3, the binder resin (Resin-F) represented by the formula (50) was used instead of the binder resin (Resin-A) used in Example 25. A single-layer type photoconductor was prepared and evaluated in the same manner as in Example 25 except that the content of the additive (Additive-A) was 2.3% by weight of the total amount of the photoconductor layer. did. The results obtained are shown in Table 3.

As described above in detail, according to the present invention, the binder resin includes a polycarbonate resin having a specific siloxane structure, and the contact angle of pure water with respect to the photoreceptor layer is set to a value within a predetermined range. Even when used for a long period of time, an electrophotographic photoreceptor having a small number of black spots and an image forming apparatus provided with the same can be obtained.
Therefore, the electrophotographic photosensitive member of the present invention is expected to contribute to cost reduction, high speed, high performance, etc. in various image forming apparatuses such as copying machines and printers.

(A)-(b) is a figure provided in order to demonstrate the basic structure and deformation | transformation structure of a single layer type photoreceptor. It is a figure provided in order to demonstrate the relationship between the contact angle of the pure water with respect to the polycarbonate resin which has a specific siloxane structure, and generation | occurrence | production of a black spot. It is a figure provided in order to demonstrate the relationship between the contact angle of the pure water with respect to a photoreceptor, and generation | occurrence | production of a black spot. FIG. 2 is a diagram for explaining an image forming apparatus including an electrophotographic photosensitive member. It is a figure provided in order to demonstrate the relationship between the photosensitive drum rotational speed and generation | occurrence | production of a black spot.

10: single layer type photoreceptor 12: substrate 14: photoreceptor layer 16: barrier layer 30: copying machine 31: image forming unit 31a: image forming unit 31b: paper feeding unit 32: paper discharge 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: Photoconductor drum 42: Charger 43: Exposure source 44: Developer 45: Transfer roller

Claims (8)

A single-layer electrophotographic photosensitive member provided on the outermost surface with a photosensitive layer containing a binder resin, a hole transporting agent, and a charge generating agent,
As the binder resin, a polycarbonate resin having a siloxane structure is included at a value within a range of 35 to 60 parts by weight with respect to 100 parts by weight of the total amount of all components other than the solvent used in the photoreceptor layer,
When the total amount of the polycarbonate resin having a siloxane structure is 100 mol%, the content ratio of units having a siloxane structure is set to a value within the range of 2 to 20 mol%,
The contact angle of pure water to the polycarbonate resin having the siloxane structure (measurement temperature: 25 ° C.) is set to a value within the range of 98 to 120 °,
As the hole transport agent, a compound having a triphenylamine skeleton containing a stilbene structure is included at a value in the range of 30 to 60 parts by weight with respect to 100 parts by weight of the polycarbonate resin having the siloxane structure,
The compound having a triphenylamine skeleton containing the stilbene structure is a compound having a contact angle with respect to pure water (measurement temperature: 25 ° C.) in the resin dispersion film within a range of 90 to 120 °,
The contact angle of pure water to the photoreceptor layer (measurement temperature: 25 ° C.) is set to a value within the range of 102 to 110 ° , and
A monolayer type electrophotographic photoreceptor, wherein the thickness of the photoreceptor layer is set to a value within a range of 25 to 50 μm .   2. The single-layer electrophotographic photosensitive member according to claim 1, wherein the polycarbonate resin having a siloxane structure has a viscosity average molecular weight in a range of 10,000 to 60,000. The photoreceptor layer, as the electron transferring material, a naphthoquinone derivative, with respect to 100 parts by weight of a polycarbonate resin having a siloxane structure, according to claim 1 or 2, characterized in that it comprises a value within a range of 20 to 80 parts by weight 1. A single-layer electrophotographic photosensitive member according to 1.   The phthalocyanine pigment as the charge generating agent is included in a value within a range of 0.5 to 20 parts by weight with respect to 100 parts by weight of the polycarbonate resin having the siloxane structure. A single-layer electrophotographic photosensitive member according to claim 1. The photoreceptor layer has, as an additive, at least one selected from the group consisting of compounds represented by the following formulas (34) to (35) and (38) to (40) (additives A to B and E to G). The single layer type electrophotographic photosensitive member according to any one of claims 1 to 4, further comprising a compound.




  6. The single-layer electrophotographic photosensitive member according to claim 5, wherein the content of the additive is set to a value within a range of 1.5 to 15% by weight with respect to the total amount of the photosensitive layer. .   A single-layer electrophotographic photosensitive member according to any one of claims 1 to 6 is provided, and portions for carrying out a charging step, an exposure step, a developing step, and a transfer step are arranged around the electrophotographic photosensitive member. An image forming apparatus.   The image forming apparatus according to claim 7, wherein the developing step is a simultaneous development cleaning method.