CN107942626B

CN107942626B - Electrophotographic photoreceptor, process cartridge, and image forming apparatus

Info

Publication number: CN107942626B
Application number: CN201710871457.3A
Authority: CN
Inventors: 冈田英树
Original assignee: Kyocera Document Solutions Inc
Current assignee: Kyocera Document Solutions Inc
Priority date: 2016-10-13
Filing date: 2017-09-25
Publication date: 2021-01-15
Anticipated expiration: 2037-09-25
Also published as: CN107942626A; JP2018063358A; JP6551359B2

Abstract

The invention provides an electrophotographic photoreceptor, a process cartridge and an image forming apparatus. An electrophotographic photoreceptor (100) is provided with: a conductive substrate (101) and a photosensitive layer (102). The photosensitive layer (102) is a single layer. The photosensitive layer (102) contains: a charge generating agent, an electron transporting agent and a binder resin. The electron transport agent comprises a compound represented by the following general formula (1). The charge amount of calcium carbonate after the friction between the photosensitive layer and calcium carbonate is more than +7.0 mu C/g. In the general formula (1), p represents an integer of 2 to 5. A number of R¹Each independently represents a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an acyl group having 2 to 11 carbon atoms. A number of R¹At least 1 of them represents a halogen atom. [ CHEM 1 ]

Description

Electrophotographic photoreceptor, process cartridge, and image forming apparatus

Technical Field

The invention relates to an electrophotographic photoreceptor, a process cartridge and an image forming apparatus.

Background

Electrophotographic photoreceptors are used in electrophotographic image forming apparatuses. Examples of the electrophotographic photoreceptor include a laminated electrophotographic photoreceptor and a single-layer electrophotographic photoreceptor. The laminated electrophotographic photoreceptor comprises: a charge generation layer having a charge generation function and a charge transport layer having a charge transport function are used as the photosensitive layer. The single-layer electrophotographic photoreceptor includes a single photosensitive layer as a photosensitive layer, and the single photosensitive layer has a charge generating function and a charge transporting function.

For example, there is an electrophotographic photoreceptor having a single photosensitive layer. The photosensitive layer contains, for example, an azoquinone compound. The azoquinone compound is represented by, for example, the chemical formula (E-2).

[ CHEM 1 ]

Disclosure of Invention

However, since the photoreceptor has a photosensitive layer containing a compound represented by the chemical formula (E-2), there is still room for improvement in suppressing the occurrence of white spots in an image formed.

In view of the above-described problems, it is an object of the present invention to provide an electrophotographic photoreceptor capable of suppressing the occurrence of white spots in a formed image. Another object of the present invention is to provide a process cartridge and an image forming apparatus, which are capable of suppressing the occurrence of white spots in an image formed by providing such an electrophotographic photoreceptor.

The electrophotographic photoreceptor of the present invention includes a conductive substrate and a photosensitive layer. The photosensitive layer is a single layer. The photosensitive layer contains: a charge generating agent, an electron transporting agent and a binder resin. The electron transporting agent comprises a compound represented by the following general formula (1). After the photosensitive layer is rubbed with calcium carbonate, the charge amount of the calcium carbonate is more than +7.0 mu C/g.

[ CHEM 2 ]

In the general formula (1), p represents an integer of 2 to 5. A number of R¹Each independently represents a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an acyl group having 2 to 11 carbon atoms. A number of R¹At least 1 of them represents a halogen atom.

The process cartridge of the present invention includes the electrophotographic photoreceptor.

An image forming apparatus of the present invention includes: an electrophotographic photoreceptor, a charging section, an exposure section, a developing section, and a transfer section. The charging section charges a surface of the electrophotographic photoreceptor. The exposure section exposes the surface of the charged electrophotographic photoreceptor to form an electrostatic latent image on the surface of the electrophotographic photoreceptor. The developing section develops the electrostatic latent image into a toner image. The transfer section transfers the toner image from the electrophotographic photoreceptor to a transfer object. The charging section charges the surface of the electrophotographic photoreceptor to a positive polarity. The electrophotographic photoreceptor is the above electrophotographic photoreceptor.

According to the electrophotographic photoreceptor of the present invention, the generation of white spots in the formed image can be suppressed. Further, according to the process cartridge and the image forming apparatus of the present invention, by providing such an electrophotographic photoreceptor, it is possible to suppress the occurrence of white spots in the formed image.

Drawings

Fig. 1(a), 1(b), and 1(c) are cross-sectional views each showing an example of an electrophotographic photoreceptor according to an embodiment of the present invention.

Fig. 2 is a diagram for explaining a method of measuring the charge amount of calcium carbonate after the photosensitive layer and calcium carbonate have been rubbed.

Fig. 3 is a diagram illustrating an example of the configuration of an image forming apparatus including an electrophotographic photoreceptor according to an embodiment of the present invention.

FIG. 4 shows a schematic view of a compound represented by the formula (1-1)¹H-NMR spectrum, and the compound is contained in the electrophotographic photoreceptor according to the embodiment of the present invention.

Detailed Description

Hereinafter, embodiments of the present invention will be described in detail. However, the present invention is not limited to the following embodiments. The present invention can be implemented with appropriate modifications within the scope of the object of the present invention. Note that, although the description may be omitted as appropriate, the gist of the present invention is not limited thereto.

Hereinafter, the compound and its derivatives may be collectively referred to by adding "class" to the compound name. When a "class" is added after the compound name to indicate the polymer name, the repeating unit indicating the polymer is derived from the compound or a derivative thereof. The reactions represented by the reaction formulae (R-1) and (R-1) may be referred to as reactions (R-1) and (R-1), respectively.

Hereinafter, unless otherwise specified, a halogen atom, an alkyl group having 1 to 10 carbon atoms, an alkyl group having 1 to 6 carbon atoms, an alkyl group having 1 to 3 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, an alkoxy group having 1 to 3 carbon atoms, an aryl group having 6 to 14 carbon atoms, and an aryl group having 6 to 10 carbon atoms each have the following meanings.

The halogen atom (halogen group) is, for example, a fluorine atom (fluoro group), a chlorine atom (chloro group), a bromine atom (bromo group) or an iodine atom (iodo group).

The alkyl group having 1 to 10 carbon atoms, the alkyl group having 1 to 6 carbon atoms and the alkyl group having 1 to 3 carbon atoms are each linear or branched and unsubstituted. Examples of the alkyl group having 1 to 10 carbon atoms include: methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, n-pentyl, isopentyl, neopentyl, 1, 2-dimethylpropyl, hexyl, heptyl, octyl, nonyl or decyl. Examples of the alkyl group having 1 to 6 carbon atoms include those having 1 to 6 carbon atoms among the groups described in the examples of the alkyl group having 1 to 10 carbon atoms. Examples of the alkyl group having 1 to 3 carbon atoms are groups having 1 to 3 carbon atoms among the groups described in the examples of the alkyl group having 1 to 10 carbon atoms.

The alkoxy group having 1 to 6 carbon atoms and the alkoxy group having 1 to 3 carbon atoms are each linear or branched and unsubstituted. Examples of the alkoxy group having 1 to 6 carbon atoms include: methoxy, ethoxy, n-propoxy, isopropoxy, n-butoxy, sec-butoxy, tert-butoxy, n-pentoxy, isopentoxy, neopentoxy or hexyl. Examples of the alkoxy group having 1 to 3 carbon atoms are groups having 1 to 3 carbon atoms among the groups described in the examples of the alkoxy group having 1 to 6 carbon atoms.

The aryl group having 6 to 14 carbon atoms and the aryl group having 6 to 10 carbon atoms are both unsubstituted. Examples of the aryl group having 6 to 14 carbon atoms are: phenyl, naphthyl, indacenyl (indacenyl), biphenylene (Biphenylenyl), acenaphthylene (acenaphthylene), anthryl or phenanthryl. Examples of the aryl group having 6 to 10 carbon atoms include phenyl and naphthyl.

< electrophotographic photoreceptor >

The present embodiment relates to an electrophotographic photoreceptor (hereinafter, may be referred to as a photoreceptor). Hereinafter, the structure of the photoreceptor 100 will be described with reference to fig. 1. Fig. 1 is a cross-sectional view showing an example of a photoreceptor 100 according to the present embodiment.

As shown in fig. 1(a), the photoreceptor 100 includes, for example, a conductive substrate 101 and a photosensitive layer 102. The photosensitive layer 102 is a single layer (one layer). The photoreceptor 100 is a single-layer type photoreceptor having a single photosensitive layer 102.

As shown in fig. 1(b), the photoreceptor 100 may also include a conductive substrate 101, a photosensitive layer 102, and an intermediate layer 103 (undercoat layer). The intermediate layer 103 is provided between the conductive substrate 101 and the photosensitive layer 102. As shown in fig. 1(a), the photosensitive layer 102 may be directly provided on the conductive substrate 101. Alternatively, as shown in fig. 1(b), the photosensitive layer 102 may be provided on the conductive substrate 101 via the intermediate layer 103.

As shown in fig. 1(c), the photoreceptor 100 may include: a conductive substrate 101, a photosensitive layer 102, and a protective layer 104. The passivation layer 104 is disposed on the photosensitive layer 102.

The thickness of the photosensitive layer 102 is not particularly limited as long as the photosensitive layer can sufficiently function as a photosensitive layer. The thickness of the photosensitive layer 102 is preferably 5 μm to 100 μm, and more preferably 10 μm to 50 μm.

In order to suppress the generation of white spots in the formed image, it is preferable that the photosensitive layer 102 is disposed as the outermost layer of the photoreceptor 100.

The structure of the photoreceptor 100 is described above with reference to fig. 1. The photoreceptor will be described in more detail below.

< photosensitive layer >

The photosensitive layer contains: a charge generating agent, an electron transporting agent and a binder resin. The photosensitive layer may further contain a hole-transporting agent. The photosensitive layer may contain additives as necessary. The single photosensitive layer contains: a charge generating agent, an electron transporting agent, a binder resin, and an ingredient (for example, a hole transporting agent or an additive) added as needed.

The photosensitive layer contains a compound represented by chemical formula (1) (hereinafter, sometimes referred to as compound (1)) as an electron-transporting agent. The charge amount of calcium carbonate (hereinafter, sometimes referred to as the charge amount of calcium carbonate) is + 7.0. mu.C/g or more after the photosensitive layer is rubbed against calcium carbonate. Thus, the photoreceptor of the present embodiment can suppress the occurrence of white spots in the formed image. The reason is presumed as follows.

For ease of understanding, a description will first be made of one reason why white dots are generated in the formed image. When a recording medium (e.g., paper) is brought into contact with a photoreceptor during image formation, a minute component (e.g., paper dust) of the recording medium may adhere to the surface of the photoreceptor. When the minute components of the recording medium adhere to the surface of the photoreceptor, light for exposing the photoreceptor is sometimes blocked by the minute components in the exposure step of image formation. The surface potential of the portion of the surface of the photoreceptor where the light used for exposure is blocked by the fine component is difficult to be lowered. Since the toner is less likely to adhere to a portion where the reduction of the surface potential is insufficient, white spots are generated in the formed image.

Here, when the recording medium comes into contact with the photoreceptor during image formation, the minute components of the recording medium rub against the photoreceptor, and the minute components may be charged to a negative polarity or a positive polarity lower than an expected value. However, the photosensitive layer of the photoreceptor of the present embodiment contains the compound (1). The compound (1) has a predetermined skeleton, and a substituent (corresponding to R) bonded to the phenyl group in the compound (1)¹) The number of (B) is 2 to 5, and these substituents (corresponding to R)¹) At least 1 of which is a halogen atom. Therefore, the electronegativity of compound (1) is high. When the fine component comes into contact with the photoreceptor of the present embodiment and the fine component rubs against the photoreceptor containing the compound (1) having a high electronegativity, the fine component is charged to a positive polarity equal to or higher than a desired value. In the charging step of image formation, when the surface of the photoreceptor is charged to a positive polarity, the surface of the photoreceptor charged to the positive polarity and the fine component having the positive polarity greater than the desired value of the charge form an electrical repulsion therebetween. The larger the positive charge amount of the fine component, the larger the electric repulsion between the fine component and the surface of the photoreceptor. This makes it difficult for the fine components to adhere to the surface of the photoreceptor. Thereby enabling to suppress the generation of white spots in the formed image.

(charged amount of calcium carbonate)

The charge amount of calcium carbonate is + 7.0. mu.C/g or more. Calcium carbonate is a main component of paper dust, which is an example of a minute component of a recording medium. If the charge amount of calcium carbonate is less than + 7.0. mu.C/g, the electrification of the fine component after the photoreceptor and the fine component of the recording medium are rubbed is insufficient, and white spots are generated in the formed image. The amount of charge of calcium carbonate is preferably + 7.0. mu.C/g to + 15.0. mu.C/g, more preferably + 8.0. mu.C/g to + 9.5. mu.C/g, and still more preferably + 9.0. mu.C/g to + 9.5. mu.C/g. For example, by containing the compound (1) as an electron-transporting agent, the charge amount of calcium carbonate can be adjusted to + 7.0. mu.C/g or more. Further, the charge amount of calcium carbonate can be adjusted by changing at least one of the kind of the compound (1), the kind of the charge generating agent, the kind of the binder resin, and the kind of the hole transporting agent.

Hereinafter, a method for measuring the charge amount of calcium carbonate after the photosensitive layer 102 and calcium carbonate are rubbed will be described with reference to fig. 2. The charge amount of calcium carbonate was measured by performing the first step, the second step, the third step, and the fourth step. In the first step, 2 photosensitive layers 102 are prepared. One of the 2 photosensitive layers 102 is a first photosensitive layer 102 a. The other photosensitive layer 102 is a second photosensitive layer 102 b. The first photosensitive layer 102a and the second photosensitive layer 102b are circular with a diameter of 3 cm. In the second step, 0.007g of calcium carbonate was supported on the first photosensitive layer 102 a. Thereby, the calcium carbonate layer 24 made of calcium carbonate is formed. Next, the second photosensitive layer 102b is placed on the calcium carbonate layer 24. In the third step, the first photosensitive layer 102a is rotated at a rotation speed of 60rpm for 60 seconds while the second photosensitive layer 102b is fixed in an atmosphere at a temperature of 23 ℃ and a relative humidity of 50% RH. Thus, calcium carbonate contained in the calcium carbonate layer 24 rubs between the first photosensitive layer 102a and the second photosensitive layer 102b to charge the calcium carbonate. In the fourth step, the charged calcium carbonate is attracted by a charge amount measuring device. And measuring the total electric quantity Q and the mass M of the calcium carbonate after attraction by using an electric quantity measuring device, and calculating the electric quantity of the calcium carbonate according to the formula Q/M. Specifically, the charge amount of calcium carbonate was measured by the method described in the examples. A method for measuring the charge amount of calcium carbonate after the photosensitive layer 102 and calcium carbonate have been rubbed together is described above with reference to fig. 2.

(Electron transport agent)

The electron transporting agent comprises the compound (1). Since the photosensitive layer contains the compound (1) as the electron transporting agent, when the recording medium is brought into contact with the photoreceptor, a minute component (for example, paper powder) of the recording medium and the photoreceptor containing the compound (1) having a high electronegativity rub against each other, and the minute component can be charged to a desired positive value.

The compound (1) is represented by the following general formula (1). The compound (1) is a naphthoquinone derivative.

[ CHEM 3 ]

R in the general formula (1)¹The halogen atom (halogen group) represented is preferably: a chlorine atom (chloro group) or a fluorine atom (fluoro group), and more preferably a chlorine atom (chloro group).

R in the general formula (1)¹The alkyl group having 1 to 6 carbon atoms is preferably an alkyl group having 1 to 3 carbon atoms, and more preferably a methyl group or an ethyl group.

R in the general formula (1)¹The alkoxy group having 1 to 6 carbon atoms is preferably an alkoxy group having 1 to 3 carbon atoms.

R in the general formula (1)¹Examples of the acyl group having 2 to 11 carbon atoms include groups represented by the following general formula (1a) or (1 b). R¹The acyl group having 2 to 11 carbon atoms is preferably a group represented by the general formula (1a), and more preferably a benzoyl group.

[ CHEM 4 ]

In the general formula (1a), Ar¹Represents an aryl group having 6 to 10 carbon atoms.

[ CHEM 5 ]

In the general formula (1b), R²Represents an alkyl group having 1 to 10 carbon atoms.

In the general formula (1), p represents an integer of 2 to 5. That is, 2 or more and 5 or less substituents R¹Bound to a phenyl group. 2 or more substituents R¹The binding to the phenyl group can suppress the occurrence of white spots in the formed image. p preferably represents 2 or 3, more preferably 3.

In the general formula (1), a plurality of R¹At least 1 of them represents a halogen atom. Therefore, the compound (1) necessarily has a halogen atom. A number of R¹At least 1 of them is a halogen atom, and the occurrence of white spots in the formed image can be suppressed. Preferably a number of R¹1 or more and 3 or less in (A) represent a halogen atom, and more preferably several R ¹2 or 3 in (A) represent a halogen atom, and more preferably a plurality of R¹3 of (a) represent a halogen atom.

In the general formula (1), R¹The binding position (substitution position) of (c) is not particularly limited. R¹Can be bonded to any of the ortho, meta and para positions of the phenyl group. R¹Preferably in the ortho or para position relative to the phenyl group. When p represents 2, 2R are preferable¹To the 2 ortho positions of the phenyl group, or to the para and ortho positions of the phenyl group. In the case where p represents 3, 3R¹Preferably to the 2 ortho and para positions of the phenyl group.

In order to suppress the occurrence of white spots in the formed image, p and R in the general formula (1) are preferable¹The following compound (1). p represents 2 or 3. A number of R¹Each independently represents a halogen atom, an alkyl group having 1 to 6 carbon atoms, or an acyl group having 2 to 11 carbon atoms (preferably, a group represented by the general formula (1 a)). A number of R¹At least 1 of them represents a halogen atom.

In order to suppress the occurrence of white spots in the formed image, p and R in the general formula (1) are more preferable¹The following compound (1). p represents 2 or 3. A number of R¹Each independently represents a halogen atom, an alkyl group having 1 to 3 carbon atoms, or a benzoyl group. A number of R¹At least 1 of them represents a halogen atom.

More preferred examples are those wherein p represents 2 or 3, 2 or 3R¹Both represent halogen atoms.

In still more preferred other examples, p represents 2, 2R¹One of them represents a halogen atom, and the other represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an acyl group having 2 to 11 carbon atoms. It is also preferred that p represents 2, 2R¹One of them represents a halogen atom, and the other represents an alkyl group having 1 to 6 carbon atoms or an acyl group having 2 to 11 carbon atoms. More preferably, p represents 2, 2R¹One of them represents a halogen atom, and the other represents an acyl group having 2 to 11 carbon atoms. More preferably, p represents 2, 2R¹One of them represents a halogen atom, and the other represents a group represented by the general formula (1 a). Particularly preferably, p represents 2, 2R¹One of them represents a halogen atom and the other represents a benzoyl group.

In still more preferred other examples, p represents 3, 3R¹Wherein 1 represents a halogen atom and 3R¹Wherein 2 of (a) represents an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms or an acyl group having 2 to 11 carbon atoms. It is also preferred that p represents 3, 3R¹Wherein 1 represents a halogen atom and 3R¹Wherein 2 of the groups represent an alkyl group having 1 to 6 carbon atoms or a group represented by the general formula (1 a). More preferably, p represents 3, 3R¹Wherein 1 represents a halogen atom and 3R¹Wherein 2 of the above groups represent an alkyl group having 1 to 3 carbon atoms or a benzoyl group. More preferably, p represents 3, 3R¹Wherein 1 represents a halogen atom and 3R ¹2 in (a) represent an alkyl group having 1 to 3 carbon atoms. Particularly preferablyP represents 3, 3R¹Wherein 1 represents a halogen atom and 3R¹Each 2 of (a) represents independently a methyl group or an ethyl group.

The compound (1) is preferably a compound represented by any one of the chemical formulae (1-1) to (1-4) from the viewpoint of suppressing the occurrence of white spots in the formed image. Hereinafter, the compounds represented by the chemical formulas (1-1) to (1 to 4) may be referred to as compounds (1-1) to (1 to 4), respectively. In order to suppress the generation of white spots in the formed image, the compounds (1-4) can be used.

[ CHEM 6 ]

[ CHEM 7 ]

[ CHEM 8 ]

[ CHEM 9 ]

The compound (1) can be produced, for example, by the following reaction (R-1) or a method similar thereto. In addition to this reaction, an appropriate step may be included as necessary. In the reaction formula shown in reaction (R-1), R¹And p and R in the formula (1)¹And p have the same meaning.

[ CHEM 10 ]

In the reaction (R-1), 1 molar equivalent of the compound (a) is reacted with 1 molar equivalent of the compound (B) to obtain 1 molar equivalent of the compound (1). It is preferable to add 1 to 5 moles of the compound (B) to 1 mole of the compound (a). The reaction temperature of the reaction (R-1) is preferably 50 ℃ to 150 ℃. The reaction time of the reaction (R-1) is preferably 1 hour to 10 hours. The reaction (R-1) may be carried out in a solvent. The solvent is, for example, a polar solvent. The polar solvent is, for example, acetic acid or dimethylformamide. After the reaction (R-1) is carried out, the obtained compound (1) may be purified. The purification method is, for example, a well-known method (for example, filtration, chromatography or crystallization).

The photosensitive layer may contain, in addition to the compound (1), an electron-transporting agent other than the compound (1) (hereinafter, sometimes referred to as another electron-transporting agent). Other electron transport agents are for example: quinone compounds, imide compounds, hydrazone compounds, thiopyran compounds, trinitrothioxanthone compounds, 3, 4, 5, 7-tetranitro-9-fluorenone compounds, dinitroanthracene compounds, dinitroacridine compounds, tetracyanoethylene, 2, 4, 8-trinitrothioxanthone, dinitrobenzene, dinitroacridine, succinic anhydride, maleic anhydride or dibromomaleic anhydride other than the compound (1). Quinone compounds other than the compound (1) include, for example: a diphenoquinone compound, an azoquinone compound, an anthraquinone compound, a naphthoquinone compound, a nitroanthraquinone compound, or a dinitroanthraquinone compound. The electron-transporting agent may be used alone or in combination of two or more. The content of the compound (1) is preferably 80% by mass or more, more preferably 90% by mass or more, and particularly preferably 100% by mass, relative to the total mass of the electron transporting agent.

The content of the compound (1) as the electron transport agent is preferably 20 parts by mass or more and 40 parts by mass or less with respect to 100 parts by mass of the binder resin. When the content of the compound (1) is 20 parts by mass or more per 100 parts by mass of the binder resin, the electrical characteristics (hereinafter referred to as sensitivity characteristics) of the photoreceptor are easily improved. If the content of the compound (1) is 40 parts by mass or less with respect to 100 parts by mass of the binder resin, the compound (1) is easily dissolved in a solvent for forming a photosensitive layer, and a uniform photosensitive layer is easily formed.

(Charge generating agent)

The charge generating agent is not particularly limited as long as it is a charge generating agent for a photoreceptor. Charge generators such as phthalocyanine pigments, perylene pigments, disazo pigments, trisazo pigments, dithione pyrrolopyrrole (dithioketo-pyrrolole) pigments, metal-free naphthalocyanine pigments, metal naphthalocyanine pigments, squaric acid pigments, indigo pigments, azulene pigments, cyanine pigments, powders of inorganic photoconductive materials (e.g., selenium-tellurium, selenium-arsenic, cadmium sulfide or amorphous silicon), pyran pigments, anthanthrone pigments, triphenylmethane pigments, threne pigments, toluidine pigments, pyrazoline pigments or quinacridone pigments. The charge generating agent may be used alone or in combination of two or more.

The phthalocyanine-based pigment is, for example, metal-free phthalocyanine or metal phthalocyanine. The metal phthalocyanine is, for example, oxytitanium phthalocyanine, hydroxygallium phthalocyanine or chlorogallium phthalocyanine. The oxytitanium phthalocyanine is represented by the chemical formula (CGM 1). The metal-free phthalocyanine is represented by the chemical formula (CGM 2). The phthalocyanine pigment may be either crystalline or amorphous. The crystal shape (for example, α -type, β -type, Y-type, V-type, or II-type) of the phthalocyanine pigment is not particularly limited, and phthalocyanine pigments having various crystal shapes can be used.

[ CHEM 11 ]

[ CHEM 12 ]

Examples of metal phthalocyanine-free crystals are: an X-type crystal of metal-free phthalocyanine (hereinafter, sometimes referred to as X-type metal-free phthalocyanine). Examples of the crystal of oxytitanium phthalocyanine include: an α -type, β -type or Y-type crystal of oxytitanium phthalocyanine (hereinafter, sometimes referred to as "α -type, β -type or Y-type oxytitanium phthalocyanine"). Crystals of hydroxygallium phthalocyanine such as V-type crystals of hydroxygallium phthalocyanine.

For example, in a digital optical image forming apparatus (for example, a laser printer or a facsimile machine using a light source such as a semiconductor laser), a photoreceptor having sensitivity in a wavelength region of 700nm or more is preferably used. The charge generating agent is preferably a phthalocyanine-based pigment, more preferably a metal-free phthalocyanine or oxytitanium phthalocyanine, and still more preferably an X-type metal-free phthalocyanine or a Y-type oxytitanium phthalocyanine, from the viewpoint of having a high quantum yield in a wavelength region of 700nm or more. In order to improve sensitivity characteristics particularly in the case where the compound (1) is contained as an electron transporting agent in the photosensitive layer, the charge generating agent is more preferably Y-type oxytitanium phthalocyanine.

For example, Y-type oxytitanium phthalocyanine has a main peak at 27.2 ° of the bragg angle (2 θ ± 0.2 °) in the CuK α characteristic X-ray diffraction spectrum. The main peak in the CuK α characteristic X-ray diffraction spectrum means a peak having a first or second large intensity in a range where the bragg angle (2 θ ± 0.2 °) is 3 ° or more and 40 ° or less.

An example of a method for measuring CuK α characteristic X-ray diffraction spectrum will be described. A sample (oxytitanium phthalocyanine) was filled in a sample holder of an X-ray diffraction apparatus (for example, "RINT (Japanese registered trademark) 1100" manufactured by Rigaku Corporation), and X-ray wavelengths characterized by an X-ray tube Cu, a tube voltage of 40kV, a tube current of 30mA and CuK. alpha. were measured

Under the conditions of (1), an X-ray diffraction spectrum was measured. For example, the measurement range (2 θ) is 3 ° to 40 ° (start angle: 3 °; stop angle: 40 °), and the scanning speed is 10 °/min.

In the photoreceptor used in the image forming apparatus using a short-wavelength laser light source (for example, a laser light source having a wavelength of 350nm to 550 nm), an anthraquinone-based pigment is preferably used as the charge generating agent.

The content of the charge generating agent is preferably 0.1 part by mass or more and 50 parts by mass or less, more preferably 0.5 part by mass or more and 30 parts by mass or less, and particularly preferably 0.5 part by mass or more and 4.5 parts by mass or less, with respect to 100 parts by mass of the binder resin contained in the photosensitive layer.

(hole transport agent)

Hole-transporting agents such as: triphenylamine derivatives, diamine derivatives (e.g., N ' -tetraphenylbenzidine derivatives, N ' -tetraphenylbenzenediamine derivatives, N ' -tetraphenylnaphthalenediamine derivatives, N ' -tetraphenylphenylenediamine (N, N ' -tetraphenylphenylenediamine) derivatives or bis (aminophenylvinyl) benzene derivatives), oxadiazole compounds (e.g., 2, 5-bis (4-methylaminophenyl) -1, 3, 4-oxadiazole), styrene compounds (e.g., 9- (4-diethylaminostyryl) anthracene), carbazole compounds (e.g., polyvinylcarbazole), organic polysilane compounds, pyrazoline compounds (e.g., 1-phenyl-3- (p-dimethylaminophenyl) pyrazoline), hydrazone compounds, indole compounds, oxazole compounds, isoxazole compounds, thiazole compounds, thiadiazole compounds, imidazole compounds, pyrazole compounds or triazole compounds. The hole-transporting agent may be used alone or in combination of two or more.

An example of the hole transporting agent is a compound represented by general formula (2) (hereinafter, sometimes referred to as compound (2)).

[ CHEM 13 ]

In the general formula (2), R²¹～R²⁶Each independently represents an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms. r, s, v and w are each independently an integer of 0 to 5. t and u are each independently an integer of 0 to 4.

In the general formula (2), R²¹～R²⁶Each independently preferably represents an alkyl group having 1 to 6 carbon atoms, and more preferably represents a methyl group. r, s, v and w are each independently preferably 0 or 1. t and u are each independently preferably 0 or 1, more preferably 0.

Specific examples of the compound (2) include compounds represented by the following chemical formula (2-1) (hereinafter, sometimes referred to as compound (2-1)).

[ CHEM 14 ]

The content of the compound (2) is preferably 80% by mass or more, more preferably 90% by mass or more, and particularly preferably 100% by mass, relative to the mass of the hole transporting agent.

The content of the hole transporting agent contained in the photosensitive layer is preferably 10 parts by mass or more and 200 parts by mass or less, and more preferably 10 parts by mass or more and 100 parts by mass or less, with respect to 100 parts by mass of the binder resin.

(Binder resin)

Examples of binding resins are: a thermoplastic resin, a thermosetting resin, or a photocurable resin. Thermoplastic resins such as: polycarbonate resins, polyarylate resins, styrene-butadiene copolymers, styrene-acrylonitrile copolymers, styrene-maleic acid copolymers, acrylic polymers, styrene-acrylic acid copolymers, polyethylene resins, ethylene-vinyl acetate copolymers, chlorinated polyethylene resins, polyvinyl chloride resins, polypropylene resins, ionomer resins, vinyl chloride-vinyl acetate copolymers, alkyd resins, polyamide resins, polyurethane resins, polysulfone resins, diallyl phthalate resins, ketone resins, polyvinyl butyral resins, polyester resins, or polyether resins. Thermosetting resins such as: silicone resins, epoxy resins, phenolic resins, urea-formaldehyde resins or melamine resins. The photocurable resin is, for example: epoxy acrylates (acrylic acid adducts of epoxy compounds) or polyurethane-acrylates (acrylic acid adducts of polyurethane compounds). These binder resins may be used alone or in combination of two or more.

Among these resins, polycarbonate resins are preferred in view of obtaining a photosensitive layer having a relatively excellent balance among processability, mechanical properties, optical properties and abrasion resistance. Examples of the polycarbonate resin are: a bisphenol ZC type polycarbonate resin, a bisphenol C type polycarbonate resin, a bisphenol a type polycarbonate resin, a bisphenol Z type polycarbonate resin, or a polycarbonate resin having a halogen atom. In order to suppress the occurrence of white spots in the formed image, a bisphenol Z-type polycarbonate resin or a polycarbonate resin having a halogen atom is preferable.

The bisphenol Z-type polycarbonate resin is a polycarbonate resin represented by the following general formula (3) (hereinafter, may be referred to as polycarbonate resin (3)).

[ CHEM 15 ]

The polycarbonate resin having a halogen atom is, for example, a polycarbonate resin represented by the following general formula (4) (hereinafter, may be referred to as a polycarbonate resin (4)).

[ CHEM 16 ]

In the general formula (4), R⁴¹、R⁴²、R⁴⁵And R⁴⁶Each independently represents a first group, a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an aryl group having 6 to 14 carbon atoms. The first group is a group selected from the group consisting of a halogen atom, an alkyl group having 1 or more halogen atoms and having 1 or more carbon atoms and 6 or less, an alkoxy group having 1 or more halogen atoms and having 1 or more carbon atoms and 6 or less, and an aryl group having 1 or more halogen atoms and having 6 or more carbon atoms and 14 or less. R⁴¹、R⁴²、R⁴⁵And R⁴⁶At least 1 of which represents a first group. Further, the first group is a halogen atom-containing group. Since the first group is a halogen atom-containing group, the polycarbonate resin (4) necessarily has a halogen atom. R⁴³And R⁴⁴Each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms or 6 to 14 carbon atomsAryl group of (1). Y represents a cycloalkylene group having 5 to 15 carbon atoms. m and n are each independently a number satisfying the following equations (i) and (ii).

m+n＝1.00……(i)

0.00＜m≤1.00……(ii)

R⁴¹、R⁴²、R⁴⁵And R⁴⁶The halogen atom (halogen group) represented is preferably a chlorine atom (chloro group) or a fluorine atom (fluoro group).

R⁴¹、R⁴²、R⁴⁵Or R⁴⁶When an alkyl group having 1 to 6 carbon atoms and 1 to 6 halogen atoms is used, the alkyl group having 1 to 6 carbon atoms is preferably an alkyl group having 1 to 3 carbon atoms, and more preferably a methyl group. The halogen atom of the alkyl group having 1 to 6 carbon atoms is preferably a chlorine group or a fluorine group. The number of halogen atoms contained in the alkyl group having 1 to 6 carbon atoms is preferably 1 to 3. R⁴¹、R⁴²、R⁴⁵And R⁴⁶The alkyl group having 1 to 6 carbon atoms and 1 to 3 halogen atoms is preferably an alkyl group having 1 to 3 carbon atoms and 1 to 3 halogen atoms, and more preferably a trifluoromethyl group.

R⁴¹、R⁴²、R⁴⁵Or R⁴⁶When the alkoxy group having 1 or more halogen atoms and having 1 or more carbon atoms and 6 or less is used, the alkoxy group having 1 or more carbon atoms and 6 or less is preferably an alkoxy group having 1 or more carbon atoms and 3 or less. The halogen atom of the alkoxy group having 1 to 6 carbon atoms is preferably a chlorine group or a fluorine group. The number of halogen atoms contained in the alkoxy group having 1 to 6 carbon atoms is preferably 1 to 3. R⁴¹、R⁴²、R⁴⁵And R⁴⁶The alkoxy group having 1 or more halogen atoms and having 1 or more carbon atoms to 6 or less is preferably an alkoxy group having 1 or more carbon atoms to 3 or less carbon atoms and having 1 or more halogen atoms to 3 or less.

R⁴¹、R⁴²、R⁴⁵Or R⁴⁶Represents an aryl group having 1 or more halogen atoms and 6 or more carbon atoms and 14 or less carbon atomsIn the case of (3), the aryl group having 6 to 14 carbon atoms is preferably an aromatic monocyclic hydrocarbon group having 6 to 14 carbon atoms, and more preferably a phenyl group. The halogen atom of the aryl group having 6 to 14 carbon atoms is preferably a chlorine group or a fluorine group, and more preferably a fluorine group. The number of halogen atoms contained in the aryl group having 6 to 14 carbon atoms is preferably 1 to 3, and more preferably 1. R⁴¹、R⁴²、R⁴⁵And R⁴⁶The aryl group having 1 or more halogen atoms and 6 or more and 14 or less carbon atoms is preferably an aryl group having 1 or more and 3 or less halogen atoms and 6 or more and 14 or less carbon atoms, more preferably an aromatic monocyclic hydrocarbon group having 1 or more and 3 or less halogen atoms and 6 or more and 14 or less carbon atoms, still more preferably a fluorophenyl group, and particularly preferably a p (p) -fluorophenyl group.

R⁴¹、R⁴²、R⁴⁵And R⁴⁶The alkyl group having 1 to 6 carbon atoms is preferably an alkyl group having 1 to 3 carbon atoms, and more preferably a methyl group.

R⁴¹、R⁴²、R⁴⁵And R⁴⁶The alkoxy group having 1 to 6 carbon atoms is preferably an alkoxy group having 1 to 3 carbon atoms.

R⁴¹、R⁴²、R⁴⁵And R⁴⁶The aryl group having 6 to 14 carbon atoms is preferably an aromatic monocyclic hydrocarbon group having 6 to 14 carbon atoms, and more preferably a phenyl group.

R⁴¹And R⁴²The bonding position of (3) is not particularly limited. R relative to the oxygen atom to which the phenyl group is bonded⁴¹Bound to the ortho or para position of the phenyl group. R relative to the oxygen atom to which the phenyl group is bonded⁴²Also bound to the ortho or para position of the phenyl group. R relative to the oxygen atom to which the phenyl group is bonded⁴¹And R⁴²Preferably in the ortho position relative to the phenyl groups.

To suppress the generation of white spots in the formed image, R⁴¹、R⁴²、R⁴⁵And R⁴⁶Each independently represents a first group selected from the group consisting of a hydrogen atom and an alkyl group having 1 to 6 carbon atomsA group selected from the group consisting of a halogen atom, an alkyl group having 1 or more halogen atoms and having 1 or more carbon atoms to 6 or less, and an aryl group having 1 or more halogen atoms and having 6 or more carbon atoms to 14 or less, R⁴¹、R⁴²、R⁴⁵And R⁴⁶At least 1 of them preferably represents a first group.

In a preferred example of suppressing the occurrence of white spots in the formed image, R is⁴¹And R⁴²Represents a hydrogen atom, R⁴⁵And R⁴⁶One or both of (a) and (b) represent an alkyl group having 1 or more halogen atoms and having 1 or more carbon atoms to 6 or less or an aryl group having 1 or more halogen atoms and having 6 or more carbon atoms to 14 or less.

In another preferred example of suppressing the generation of white spots in the formed image, R⁴¹And R⁴²Represents a halogen atom, R⁴⁵And R⁴⁶Represents an alkyl group having 1 to 6 carbon atoms.

In order to suppress the occurrence of white spots in the formed image, it is preferable that the polycarbonate resin (4) has a large number of halogen atoms. The number of halogen atoms in the polycarbonate resin (4) is preferably 1 to 6, more preferably 2 to 6, and particularly preferably 6.

Next, for R in the general formula (4)⁴³And R⁴⁴The description is given. In the general formula (4), R⁴³And R⁴⁴Each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or an aryl group having 6 to 14 carbon atoms.

The alkyl group having 1 to 6 carbon atoms represented by R43 and R44 is preferably an alkyl group having 1 to 3 carbon atoms. R⁴³And R⁴⁴The alkoxy group having 1 to 6 carbon atoms is preferably an alkoxy group having 1 to 3 carbon atoms. R⁴³And R⁴⁴The aryl group having 6 to 14 carbon atoms is preferably an aryl group having 6 to 10 carbon atoms, and more preferably a phenyl group.

R⁴³And R⁴⁴The bonding position of (3) is not particularly limited. R relative to the oxygen atom to which the phenyl group is bonded⁴³Bound to the ortho position of the phenyl groupOr para. R relative to the oxygen atom to which the phenyl group is bonded⁴⁴Also bound to the ortho or para position of the phenyl group. Preferably, R is relative to the oxygen atom to which the phenyl group is bonded⁴³And R⁴⁴Preferably in the ortho position relative to the phenyl groups.

To suppress the generation of self-dots in the formed image, R⁴³And R⁴⁴Preferably represents a hydrogen atom.

Next, Y in the general formula (4) will be explained. In the general formula (4), Y represents a cycloalkylene group (cycloalkylidene) having 5 to 15 carbon atoms. The cycloalkylene group having 5 to 15 carbon atoms represented by Y is a divalent group in which 2 bonds are bonded to 1 carbon atom among carbon atoms forming the cycloalkane. The cycloalkylene group having 5 to 15 carbon atoms is represented by the following general formula. In the general formula, q represents an integer of 1 to 11 inclusive, and represents a bond. q preferably represents an integer of 1 to 3, more preferably 2.

[ CHEM 17 ]

Cycloalkylene having 5 to 15 carbon atoms such as: cyclopentylene, cyclohexylene, cycloheptylene, cyclooctylene, cyclononylene, cyclodecylene, cycloundecylene, cyclododecylene, cyclotridecylene, cyclotetradecylene or cyclopentadecylene. The cycloalkylene group having 5 to 15 carbon atoms is preferably a cycloalkylene group having 5 to 7 carbon atoms, and more preferably a cyclohexylene (cyclohexylidene) group.

Next, m and n in the general formula (4) will be described. The polycarbonate resin (4) is composed of a repeating structural unit represented by the following general formula (4a) (hereinafter, sometimes referred to as a repeating unit (4a)) and a repeating structural unit represented by the following general formula (4b) (hereinafter, sometimes referred to as a repeating unit (4 b)). The polycarbonate resin (4) is a repeating unit (4a)) And a repeating unit (4 b). Further, R in the general formula (4a)⁴¹、R⁴²、R⁴⁵And R⁴⁶Are each independently of R in the general formula (4)⁴¹、R⁴²、R⁴⁵And R⁴⁶Have the same meaning. R in the general formula (4b)⁴³、R⁴⁴And Y is independently from R in the formula (4)⁴³、R⁴⁴And Y has the same meaning.

[ CHEM 18 ]

[ CHEM 19 ]

M in the general formula (4) represents: in the polycarbonate resin (4), the ratio (mole fraction) of the amount (mole number) of the substance of the repeating unit (4a) to the amount (mole number) of the total substance of the repeating unit (4a) and the repeating unit (4 b). N in the general formula (4) represents: in the polycarbonate resin (4), the ratio (mole fraction) of the amount (mole number) of the substance of the repeating unit (4b) to the amount (mole number) of the total substance of the repeating unit (4a) and the repeating unit (4 b). In the polycarbonate resin (4), the ratio of the amount (number of moles) of the total substance of the repeating units (4a) and the repeating units (4b) to the amount (number of moles) of the substance of all the repeating units is preferably 80% by mole or more, more preferably 90% by mole or more, and particularly preferably 100% by mole.

In the general formula (4), m and n are each independently a number satisfying the following formulas (i) and (ii). m represents a number greater than 0.00. Since m is not 0.00, the polycarbonate resin (4) must have the repeating unit (4 a). The polycarbonate resin (4) may or may not have the repeating unit (4 b). For example, when m is 1.00, n is 0.00. When m is 1.00, the polycarbonate resin (4) has only the repeating unit (4a) and does not have the repeating unit (4 b).

m+n＝1.00……(i)

0.0＜m≤1.00……(ii)

The formula (ii) is preferably 0.20. ltoreq. m.ltoreq.0.80, more preferably 0.30. ltoreq. m.ltoreq.0.70, and particularly preferably 0.40. ltoreq. m.ltoreq.0.60. When m is 0.20 or more, the occurrence of white spots in the formed image is easily suppressed. When m is 0.80 or less, it is considered that the solubility of the polycarbonate resin (4) in the solvent contained in the photosensitive layer coating liquid can be improved.

The polycarbonate resin (4) may be a random copolymer in which the repeating unit (4a) and the repeating unit (4b) are randomly copolymerized; alternatively, the polycarbonate resin (4) may be an alternating copolymer in which the repeating unit (4a) and the repeating unit (4b) are alternately copolymerized; alternatively, the polycarbonate resin (4) may be a periodic copolymer in which 1 or more repeating units (4a) and 1 or more repeating units (4b) are periodically copolymerized; alternatively, the polycarbonate resin (4) may be a block copolymer in which a block formed of a plurality of repeating units (4a) and a block formed of a plurality of repeating units (4b) are copolymerized.

Preferable examples of the polycarbonate resin (4) are: a polycarbonate resin represented by the following general formula (4-1), (4-3) or (4-4), or a polycarbonate resin having a repeating unit represented by the following chemical formula (4-2). Hereinafter, the polycarbonate resins represented by the general formulae (4-1), (4-3) and (4-4) may be referred to as polycarbonate resins (4-1), (4-3) and (4-4), respectively. The polycarbonate resin having a repeating unit represented by the chemical formula (4-2) may be referred to as a polycarbonate resin (4-2).

[ CHEM 20 ]

In the general formula (4-1), m₁+n₁＝1.00，0.20≤m₁Less than or equal to 0.80. Preferably 0.30. ltoreq. m₁0.70 or less, more preferably 0.40 or less m₁Less than or equal to 0.60. The polycarbonate resin (4-1) is preferably a polycarbonate resin represented by the chemical formula (4-1-1) (hereinafter, may be referred to as the polycarbonate resin (4-1-1)).

[ CHEM 21 ]

[ CHEM 22 ]

In the polycarbonate resin (4-2), m in the general formula (4) is 1.00 and n is 0.00.

[ CHEM 23 ]

In the general formula (4-3), m₃+n₃＝1.00，0.20≤m₃Less than or equal to 0.80. Preferably 0.30. ltoreq. m₃0.70 or less, more preferably 0.40 or less m₃Less than or equal to 0.60. The polycarbonate resin (4-3) is preferably a polycarbonate resin represented by the chemical formula (4-3-1) (hereinafter, may be referred to as the polycarbonate resin (4-3-1)).

[ CHEM 24 ]

[ CHEM 25 ]

In the general formula (4-4), m₄+n₄＝1.00，0.20≤m₄Less than or equal to 0.80. Preferably 0.30. ltoreq. m₄0.70 or less, more preferably 0.40 or less m₄Less than or equal to 0.60. The polycarbonate resin (4-4) is preferably a polycarbonate resin represented by the chemical formula (4-4-1) (hereinafter, may be referred to as the polycarbonate resin (4-4-1)).

[ CHEM 26 ]

The viscosity average molecular weight of the polycarbonate resin (4) is preferably 25,000 or more, more preferably 25,000 or more and 52,500 or less. When the viscosity average molecular weight of the polycarbonate resin (4) is 25,000 or more, the abrasion resistance of the photoreceptor is easily improved. When the viscosity average molecular weight of the polycarbonate resin (4) is 52,500 or less, the polycarbonate resin (4) is easily dissolved in a solvent at the time of forming the photosensitive layer, and the viscosity of the coating liquid for photosensitive layer does not become too high. Thus, the photosensitive layer is easily formed.

The method for producing the polycarbonate resin (4) is not particularly limited as long as the polycarbonate resin (4) can be produced. One example of the method for producing the polycarbonate resin (4) is a method of polycondensing a diol compound constituting a repeating unit of the polycarbonate resin (4) with phosgene (so-called phosgene method). More specifically, for example, a method of polycondensing a diol compound represented by the following general formula (4c), a diol compound represented by the following general formula (4d), and phosgene. And R in the general formula (4c)⁴¹、R⁴²、R⁴⁵And R⁴⁶Are each independently of R in the general formula (4)⁴¹、R⁴²、R⁴⁵And R⁴⁶Have the same meaning. R in the general formula (4d)⁴³、R⁴⁴And Y is independently from R in the formula (4)⁴³、R⁴⁴And Y has the same meaning. Another example of the method for producing the polycarbonate resin (4) is a method in which a diol compound and diphenyl carbonate are subjected to an ester exchange reaction.

[ CHEM 27 ]

[ CHEM 28 ]

The content of the polycarbonate resin (3) or the polycarbonate resin (4) is preferably 80% by mass or more, more preferably 90% by mass or more, and particularly preferably 100% by mass, relative to the mass of the binder resin contained in the photosensitive layer.

(combination of materials)

In order to further suppress the occurrence of white spots in the formed image, the hole transporting agent, the electron transporting agent, and the binder resin are preferably any one of the combinations shown below. For the same reason, it is preferable that: the hole-transporting agent, the electron-transporting agent and the binder resin are any one of the combinations shown below, and the charge-generating agent is Y-type oxytitanium phthalocyanine. For the same reason, it is also preferable that: the hole-transporting agent, the electron-transporting agent and the binder resin are any one of the combinations shown below, and the charge-generating agent is an X-type metal-free phthalocyanine.

The hole transporting agent is a compound (2-1), the electron transporting agent is a compound (1-1), and the binding resin is a polycarbonate resin (4-1); alternatively, the first and second electrodes may be,

the hole transporting agent is a compound (2-1), the electron transporting agent is a compound (1-2), and the binding resin is a polycarbonate resin (4-1); alternatively, the first and second electrodes may be,

the hole transport agent is a compound (2-1), the electron transport agent is a compound (1-3), and the binding resin is a polycarbonate resin (4-1); alternatively, the first and second electrodes may be,

the hole transport agent is a compound (2-1), the electron transport agent is a compound (1-4), and the binding resin is a polycarbonate resin (4-1); alternatively, the first and second electrodes may be,

the hole transporting agent is a compound (2-1), the electron transporting agent is a compound (1-1), and the binding resin is a polycarbonate resin (4-2); alternatively, the first and second electrodes may be,

the hole transport agent is a compound (2-1), the electron transport agent is a compound (1-2), and the binding resin is a polycarbonate resin (4-2); alternatively, the first and second electrodes may be,

the hole transport agent is a compound (2-1), the electron transport agent is a compound (1-3), and the binding resin is a polycarbonate resin (4-2); alternatively, the first and second electrodes may be,

the hole transport agent is a compound (2-1), the electron transport agent is a compound (1-4), and the binding resin is a polycarbonate resin (4-2); alternatively, the first and second electrodes may be,

the hole transport agent is a compound (2-1), the electron transport agent is a compound (1-1), and the binding resin is a polycarbonate resin (4-3); alternatively, the first and second electrodes may be,

the hole transport agent is a compound (2-1), the electron transport agent is a compound (1-2), and the binding resin is a polycarbonate resin (4-3); alternatively, the first and second electrodes may be,

the hole transport agent is a compound (2-1), the electron transport agent is a compound (1-3), and the binding resin is a polycarbonate resin (4-3); alternatively, the first and second electrodes may be,

the hole transport agent is a compound (2-1), the electron transport agent is a compound (1-4), and the binding resin is a polycarbonate resin (4-3); alternatively, the first and second electrodes may be,

the hole transport agent is a compound (2-1), the electron transport agent is a compound (1-1), and the binding resin is a polycarbonate resin (4-4); alternatively, the first and second electrodes may be,

the hole transport agent is a compound (2-1), the electron transport agent is a compound (1-2), and the binding resin is a polycarbonate resin (4-4); alternatively, the first and second electrodes may be,

the hole transport agent is a compound (2-1), the electron transport agent is a compound (1-3), and the binding resin is a polycarbonate resin (4-4); alternatively, the first and second electrodes may be,

the hole transporting agent is the compound (2-1), the electron transporting agent is the compound (1-4), and the binding resin is the polycarbonate resin (4-4).

(additives)

The additives may be, for example: degradation inhibitors (e.g., antioxidants, radical scavengers, singlet quenchers, or ultraviolet absorbers), softening agents, surface modifiers, extenders, thickeners, dispersion stabilizers, waxes, acceptors, donors, surfactants, plasticizers, sensitizers, or leveling agents. The antioxidant may be, for example: hindered phenols (e.g., di-t-butyl-p-cresol), hindered amines, p-phenylenediamine, arylalkanes, hydroquinones, spirochromans (spirochromans), spiroindanones (spiroindanones), or derivatives thereof; organic sulfur compounds or organic phosphorus compounds.

< conductive substrate >

The conductive substrate is not particularly limited as long as it can be used as a conductive substrate of a photoreceptor. The conductive substrate may be formed of a conductive material at least on the surface portion. The conductive substrate may be, for example, a conductive substrate formed of a material having conductivity. The conductive substrate may be a conductive substrate coated with a material having conductivity, for example. Conductive materials such as: aluminum, iron, copper, tin, platinum, silver, vanadium, molybdenum, chromium, cadmium, titanium, nickel, palladium, indium, stainless steel, or brass. These conductive materials may be used alone, or two or more of them may be used in combination (for example, as an alloy). Among these conductive materials, aluminum or an aluminum alloy is preferable because of good charge transfer from the photosensitive layer to the conductive substrate.

The shape of the conductive substrate can be appropriately selected according to the structure of the image forming apparatus. The conductive substrate may have a sheet-like or drum-like shape, for example. The thickness of the conductive substrate may be appropriately selected according to the shape of the conductive substrate.

< intermediate layer >

The intermediate layer (undercoat layer) contains, for example, inorganic particles and a resin (resin for intermediate layer) for the intermediate layer.

It can be considered that: since the intermediate layer is present, the current generated when the photoreceptor is exposed can be smoothly flowed while maintaining an insulating state to such an extent that the occurrence of electric leakage can be suppressed, thereby suppressing an increase in resistance.

Inorganic particles such as: particles of a metal (e.g., aluminum, iron, or copper), a metal oxide (e.g., titanium dioxide, aluminum oxide, zirconium oxide, tin oxide, or zinc oxide); or particles of a non-metal oxide (e.g., silica). These inorganic particles may be used alone or in combination of two or more.

The resin for the intermediate layer is not particularly limited as long as it can be used as a resin for forming the intermediate layer. The intermediate layer may also contain additives. Examples of the additive contained in the intermediate layer are the same as those of the additive contained in the photosensitive layer.

< method for producing photoreceptor >

The photoreceptor is manufactured, for example, as follows. The photoreceptor is produced by applying a coating liquid for a photosensitive layer on a conductive substrate and drying the coating liquid. The coating liquid for photosensitive layers is produced by dissolving or dispersing a charge generating agent, an electron transporting agent, a binder resin, and components (for example, a hole transporting agent and an additive) added as needed in a solvent.

The solvent contained in the coating liquid for photosensitive layer is not particularly limited as long as it can dissolve or disperse each component contained in the coating liquid. Examples of solvents are: alcohols (e.g., methanol, ethanol, isopropanol, or butanol), aliphatic hydrocarbons (e.g., n-hexane, octane, or cyclohexane), aromatic hydrocarbons (e.g., benzene, toluene, or xylene), halogenated hydrocarbons (e.g., dichloromethane, dichloroethane, carbon tetrachloride, or chlorobenzene), ethers (e.g., dimethyl ether, diethyl ether, tetrahydrofuran, ethylene glycol dimethyl ether, diethylene glycol dimethyl ether, or propylene glycol monomethyl ether), ketones (e.g., acetone, methyl ethyl ketone, or cyclohexanone), esters (e.g., ethyl acetate or methyl acetate), dimethyl formaldehyde, dimethyl formamide, or dimethyl sulfoxide. These solvents may be used alone or in combination of two or more. In order to improve the workability in the production of the photoreceptor, a halogen-free solvent (a solvent other than halogenated hydrocarbon) is preferably used as the solvent.

The components are mixed and dispersed in a solvent to prepare a coating liquid. For the mixing or dispersing, for example, a bead mill, roll mill, ball mill, attritor, paint shaker or ultrasonic disperser can be used.

In order to improve the dispersibility of each component, for example, a surfactant may be contained in the coating liquid for photosensitive layer.

The method for applying the coating liquid for photosensitive layer is not particularly limited as long as the coating liquid can be uniformly applied to the conductive substrate. The coating method includes, for example: blade coating, dip coating, spray coating, spin coating, or bar coating.

The method for drying the coating liquid for photosensitive layer is not particularly limited as long as the solvent in the coating liquid can be evaporated. For example, there is a method of performing heat treatment (hot air drying) using a high-temperature dryer or a reduced-pressure dryer. The heat treatment conditions are, for example, a temperature of 40 ℃ to 150 ℃ and a time of 3 minutes to 120 minutes.

The method for manufacturing the photoreceptor may further include one or both of the step of forming the intermediate layer and the step of forming the protective layer, as necessary. The step of forming the intermediate layer and the step of forming the protective layer can be realized by appropriately selecting a known method.

< image Forming apparatus >

Next, an image forming apparatus 110 including the photoreceptor 100 according to the present embodiment will be described with reference to fig. 3. Fig. 3 shows an example of the configuration of the image forming apparatus 110.

The image forming apparatus 110 is not particularly limited as long as it is an electrophotographic image forming apparatus. The image forming apparatus 110 may be a monochrome image forming apparatus or a color image forming apparatus, for example. When the image forming apparatus 110 is a color image forming apparatus, the image forming apparatus 110 employs, for example, a tandem system. The tandem image forming apparatus 110 will be described below by way of example.

The image forming apparatus 110 includes:

image forming units

40a, 40b, 40c, and 40d, transfer belt 50, and fixing unit 52. Hereinafter, the

image forming units

40a, 40b, 40c, and 40d are all described as the image forming unit 40 in the case where distinction is not necessary. In the case where image forming apparatus 110 is a monochrome image forming apparatus, image forming apparatus 110 includes image forming unit 40a, and image forming units 40b to 40d are omitted.

The image forming unit 40 includes: the photoreceptor 100, the charging section 42, the exposure section 44, the developing section 46, and the transfer section 48 according to the present embodiment. The photoreceptor 100 is disposed at the center of the image forming unit 40. The photosensitive body 100 is provided to be rotatable in an arrow direction (counterclockwise direction). The charging section 42, the exposure section 44, the developing section 46, and the transfer section 48 are provided around the photoreceptor 100 in order from the upstream side in the rotation direction of the photoreceptor 100 with reference to the charging section 42. The image forming unit 40 may further include one or both of a cleaning unit (not shown) and a discharging unit (not shown).

The charging section 42 charges the surface (e.g., the circumferential surface) of the photoreceptor 100 with a positive polarity. When the photoreceptor 100 of the present embodiment is in contact with and rubbed against the recording medium P, a fine component (e.g., paper dust) of the recording medium P may be charged with a positive polarity equal to or higher than a desired value. When the surface of the photoreceptor 100 is charged to a positive polarity by the charging section 42, the surface of the photoreceptor 100 is electrically repelled from the minute components of the recording medium P triboelectrically charged to a positive polarity. As a result, the minute components of the recording medium P are less likely to adhere to the surface of the photoreceptor 100, and the occurrence of the self-point in the formed image can be suppressed.

The charging unit 42 is of a non-contact type or a contact type. Examples of the non-contact type charging unit 42 include a corotron charger and a grid charger. Examples of the contact type charging section 42 include a charging roller and a charging brush.

The exposure section 44 exposes the surface of the charged photoreceptor 100. Thereby, an electrostatic latent image is formed on the surface of the photoreceptor 100. The electrostatic latent image is formed based on image data input to the image forming apparatus 110.

The developing portion 46 supplies toner to the electrostatic latent image formed on the photosensitive body 100. Thereby, the electrostatic latent image is developed into a toner image. The photoreceptor 100 corresponds to an image carrier for carrying a toner image. The toner may be used as a one-component developer; alternatively, the toner may be mixed with a desired carrier, and the toner may be used in a two-component developer. In the case where the toner is used as the one-component developer, the developing portion 46 supplies the toner as the one-component developer to the electrostatic latent image formed on the photosensitive body 100. In the case where the toner is used in a two-component developer containing the toner and the carrier, the developing section 46 supplies the toner therein to the electrostatic latent image formed on the photosensitive body 100.

The transfer belt 50 conveys the recording medium P between the photoreceptor 100 and the transfer section 48. The transfer belt 50 is an endless belt. The transfer belt 50 is provided to be rotatable in an arrow direction (clockwise direction).

The transfer section 48 transfers the toner image developed by the developing section 46 from the photoreceptor 100 to a transfer object. The transfer section 48 is, for example, a transfer roller.

When the image forming apparatus 110 employs the direct transfer method, the transferred object corresponds to the recording medium P. In the case where the image forming apparatus 110 employs the direct transfer method, when the transfer section 48 transfers the toner image from the photoreceptor 100 to the recording medium P, the photoreceptor 100 comes into contact with the recording medium P. In the image forming apparatus 110 employing the direct transfer method, since the photoreceptor 100 is in contact with the recording medium P, a fine component (e.g., paper dust) of the recording medium P is likely to adhere to the surface of the photoreceptor 100. However, as described above, according to the photoreceptor 100 of the present embodiment, the adhesion of the fine components of the recording medium P to the surface of the photoreceptor 100 can be suppressed. Thereby enabling to preferably suppress the generation of white spots in the formed image.

The recording medium P on the transfer belt 50 is sequentially superimposed with toner images of several colors (for example, four colors of black, cyan, magenta, and yellow) by the image forming units 40a to 40d, respectively.

The fixing section 52 heats and/or pressurizes the unfixed toner image transferred to the recording medium P by the transfer section 48. The fixing unit 52 is, for example, a heating roller and/or a pressure roller. The toner image is heated and/or pressurized, whereby the toner image is fixed to the recording medium P. As a result, an image is formed on the recording medium P. The image forming apparatus 110 including the photoreceptor 100 according to the present embodiment is described above with reference to fig. 3.

< Process Cartridge >

Next, with continued reference to fig. 3, a process cartridge including the photoreceptor 100 of the present embodiment will be described. The process cartridge is a cartridge for image formation. The process cartridges correspond to the respective image forming units 40a to 40 d. The process cartridge has a photosensitive body 100. The process cartridge may include at least 1 selected from the group consisting of the charging unit 42, the exposure unit 44, the developing unit 46, and the transfer unit 48, in addition to the photoreceptor 100. The process cartridge may further include one or both of a cleaning device (not shown) and a static eliminator (not shown). The process cartridge is designed to be detachable from the image forming apparatus 110. Therefore, the process cartridge can be easily handled, and when the sensitivity characteristics and the like of the photosensitive body 100 are deteriorated, the process cartridge including the photosensitive body 100 can be easily and quickly replaced. A process cartridge including the photoreceptor 100 according to the present embodiment is described above with reference to fig. 3.

[ examples ] A method for producing a compound

The present invention will be described in more detail below with reference to examples. However, the present invention is not limited to the scope of the examples.

< Material for Forming photoreceptor >

As materials for forming the photosensitive layer of the photoreceptor, the following charge generating agent, hole transporting agent, electron transporting agent, and binder resin were prepared.

(Charge generating agent)

Y-type oxytitanium phthalocyanine and X-type metal-free phthalocyanine are prepared as charge generators. The Y-type oxytitanium phthalocyanine is represented by the chemical formula (CGM1) described in the embodiments, and is an oxytitanium phthalocyanine having a Y-type crystal structure. The X-type metal-free phthalocyanine is represented by the chemical formula (CGM2) described in the embodiments, and is a metal-free phthalocyanine having an X-type crystal structure.

(hole transport agent)

The compound (2-1) described in the embodiment was prepared as a hole transporting agent.

(Binder resin)

The polycarbonate resins (3), (4-1-1), (4-2), (4-3-1) and (4-4-1) described in the embodiment were prepared as the binder resin. The viscosity average molecular weight of the polycarbonate resin (3) was 30000. The viscosity average molecular weights of the polycarbonate resins (4-1-1), (4-2), (4-3-1) and (4-4-1) were all 50000.

(Electron transport agent)

The compounds (1-1) to (1-4) described in the embodiment were prepared as an electron-transporting agent. The compounds (1-1) to (1-4) were synthesized by the following methods.

(Synthesis of Compound (1-1))

In the reaction (r-1), a compound represented by the chemical formula (A-1) (hereinafter, referred to as compound (A-1)) and a compound represented by the chemical formula (B-1) (hereinafter, referred to as compound (B-1)) are reacted to obtain compound (1-1). Specifically, compound (A-1) (3.14g, 10mmol) and compound (B-1) (1.70g, 10mmol) were dissolved in acetic acid (50mL) to obtain an acetic acid solution. The acetic acid solution was stirred at 120 ℃ for 4 hours. After stirring for 4 hours, water was added to the acetic acid solution to obtain a mixture. The mixture was extracted with chloroform to obtain an organic layer. The organic layer was decompressed to evaporate chloroform, and a residue was obtained. The residue was purified by silica gel column chromatography using chloroform as a developing solvent. As a result, Compound (1-1) was obtained. The yield of the compound (1-1) was 2.79 g. The yield of the compound (1-1) derived from the compound (A-1) was 60 mol%.

[ CHEM 29 ]

(Synthesis of Compounds (1-2) to (1-4))

Compound (1-2) was synthesized by the same method as the synthesis of compound (1-1) except that compound (B-1) (1.70g, 10mmol) was changed to compound (B-2) (1.62g, 10 mmol). Compound (1-3) was synthesized by the same method as the synthesis of compound (1-1) except that compound (B-1) (1.70g, 10mmol) was changed to compound (B-3) (1.96g, 10 mmol). Compound (1-4) was synthesized by the same method as the synthesis of compound (1-1) except that compound (B-1) (1.70g, 10mmol) was changed to compound (B-4) (2.31g, 10 mmol). Further, the compounds (B-2) to (B-4) are represented by the following chemical formulae (B-2) to (B-4), respectively.

[ CHEM 30 ]

The first compound column in Table 1 shows the mass and amount of the compound (A-1) added in the reaction (r-1). The second compound column in Table 1 shows the mass and amount of each of the compounds (B-1) to (B-4) added in the reaction (r-1). The column of the reaction product in Table 1 shows the yield and yield of each of the compounds (1-1) to (1-4) obtained in the reaction (r-1).

[ TABLE 1 ]

Then, by¹H-NMR (proton Nuclear magnetic resonance Spectroscopy), measurementOf the Compounds (1-1) to (1-4)¹H-NMR spectrum. The magnetic field strength was set at 300 MHz. Deuterated chloroform (CDCl) was used₃) As a solvent. Tetramethylsilane (TMS) was used as an internal standard.

FIG. 4 shows the preparation of Compound (1-1)¹The H-NMR spectrum was used as a representative example of the compounds (1-1) to (1-4). Process for producing Compound (1-1)¹The chemical shift values of the H-NMR spectrum are shown below. From measured¹The H-NMR spectrum and the chemical shift values confirmed that the compound (1-1) was obtained. As for the compounds (1-2) to (1-4), the measured values were also obtained¹It was confirmed by H-NMR spectrum and chemical shift values that the compounds (1-2) to (1-4) were obtained, respectively.

Compound (1-1):¹H-NMR(300MHz，CDCl₃)δ＝8.43-8.52(m，2H)，8.36(d，1H)，7.88-7.96(m，2H)，7.64(t，1H)，7.34(t，1H)，7.11-7.24(m，2H)，6.72(d，1H)，2.32-2.56(m，2H)，2.04(s，3H)，1.06(t，3H)。

compounds represented by the following chemical formulas (E-1) to (E-2) were also prepared as electron-transporting agents. Hereinafter, the compounds represented by the chemical formulas (E-1) to (E-2) are respectively described as compounds (E-1) to (E-2).

[ CHEM 31 ]

[ CHEM 32 ]

< production of photoreceptor >

Photoreceptors (P-A1) to (P-A16) and (P-B1) to (P-B4) were manufactured using a material for forming a photosensitive layer.

(production of photoreceptor (P-A1))

Charging into a container: 2 parts by mass of X-type metal-free phthalocyanine as a charge generator, 50 parts by mass of a compound (2-1) as a hole transporting agent, 30 parts by mass of a compound (1-1) as an electron transporting agent, 100 parts by mass of a polycarbonate resin (3) as a binder resin, and 600 parts by mass of tetrahydrofuran as a solvent. The contents of the vessel were mixed for 12 hours using a ball mill to disperse the material in the solvent. Thus, a coating liquid for photosensitive layer was obtained. The coating liquid for photosensitive layer was applied to a conductive substrate (aluminum drum support, diameter 30mm, total length 238.5mm) by a blade coating method. The coating liquid for photosensitive layer applied was dried with hot air at 120 ℃ for 80 minutes. Thus, a photosensitive layer (film thickness: 30 μm) was formed on the conductive substrate. As a result, a photoreceptor (P-A1) was obtained.

(production of photoreceptors (P-A2) to (P-A16) and (P-B1) to (P-B4)

Photoreceptors (P-A2) to (P-A16) and (P-B1) to (P-B4) were produced by the same method as that for producing the photoreceptor (P-A1) except that the following three points (1) to (3) were changed.

(1) X-type metal-free phthalocyanine was used as a charge generating agent in the production of the photoreceptor (P-A1), and the types of charge generating agents shown in Table 2 were used in the production of the photoreceptors (P-A2) to (P-A16) and (P-B1) to (P-B4).

(2) The compound (1-1) was used as an electron transporting agent in the production of the photoreceptor (P-A1), and the electron transporting agents of the types shown in Table 2 were used in the production of the photoreceptors (P-A2) to (P-A16) and (P-B1) to (P-B4).

(3) Polycarbonate resin (3) was used as the binder resin in the production of the photoreceptor (P-A1), and the binder resins of the types shown in Table 2 were used in the production of the photoreceptors (P-A2) to (P-A16) and (P-B1) to (P-B4).

< measurement of calcium carbonate Charge amount >

The charge amount of calcium carbonate was measured for each of the photoreceptors (P-A1) to (P-A16) and (P-B1) to (P-B4), respectively.

Hereinafter, a method of measuring the charge amount of calcium carbonate after the photosensitive layer 102 and calcium carbonate are rubbed together will be described with reference to fig. 2. The charge amount of calcium carbonate was measured by performing the following first step, second step, third step, and fourth step. The jig 10 was used to measure the charge amount of calcium carbonate.

The jig 10 includes: a first base 12, a shaft 14, a rotary drive unit 16 (e.g., a motor), and a second base 18. The rotation driving unit 16 rotates the rotation shaft 14. The shaft 14 rotates about a rotation axis S of the shaft 14. The first base 12 is integrated with the rotary shaft 14 and rotates about the rotary shaft S. The second base 18 is fixed without rotation.

(first step)

In the first step, 2 photosensitive layers 102 are prepared. Hereinafter, one photosensitive layer 102 is referred to as a first photosensitive layer 102a, and the other photosensitive layer 102 is referred to as a second photosensitive layer 102 b. First, a first film 20 is prepared, and the first photosensitive layer 102a having a film thickness L1 of 30 μm is provided on the first film 20. Then, a second film 22 was prepared, and the second film 22 was provided with the second photosensitive layer 102b having a film thickness L2 of 30 μm. Specifically, an overhead projector (OHP) thin film is used as the first film 20 and the second film 22. The first film 20 and the second film 22 each have a circular shape with a diameter of 3 cm. A coating liquid for photosensitive layer used for producing the photoreceptor (P-1) is applied to the first film 20 and the second film 22. The coating liquid for photosensitive layer applied was dried with hot air at 120 ℃ for 80 minutes. As a result, the first film 20 including the first photosensitive layer 102a and the second film 22 including the second photosensitive layer 102b are obtained.

(second step)

In the second step, 0.007g of calcium carbonate was supported on the first photosensitive layer 102 a. Thereby, the calcium carbonate layer 24 made of calcium carbonate is formed on the first photosensitive layer 102 a. Then, the second photosensitive layer 102b is placed on the calcium carbonate layer 24. The specific steps of the second step are as follows.

First, first film 20 is fixed to first base 12 with a double-sided tape. 0.007g of calcium carbonate was placed on the first photosensitive layer 102a of the first film 20. Thereby, the calcium carbonate layer 24 made of calcium carbonate is formed on the first photosensitive layer 102 a. The second film 22 is secured to the second submount 18 with double sided tape so that the calcium carbonate layer 24 is in contact with the second photosensitive layer 102 b. Thus, the first base 12, the first film 20, the first photosensitive layer 102a, the calcium carbonate layer 24, the second photosensitive layer 102b, the second film 22, and the second base 18 are arranged in this order from the bottom up. The rotation axis S is disposed to pass through respective centers of the first base 12, the first film 20, the first photosensitive layer 102a, the second photosensitive layer 102b, the second film 22, and the second base 18.

(third step)

In the third step, the first photosensitive layer 102a is rotated at a rotation speed of 60rpm for 60 seconds in an environment where the temperature is 23 ℃ and the relative humidity is 50% RH while the second photosensitive layer 102b is fixed. Specifically, the rotation driving unit 16 is driven to rotate the shaft 14, the first base 12, the first film 20, and the first photosensitive layer 102a about the rotation axis S at a rotation speed of 60rpm for 60 seconds. Thereby, calcium carbonate contained in the calcium carbonate layer 24 is rubbed between the first photosensitive layer 102a and the second photosensitive layer 102b, and the calcium carbonate is charged.

(fourth step)

In the fourth step, the calcium carbonate charged in the third step is taken out of the jig 10, and the calcium carbonate is attracted by an electrification amount measuring apparatus (attraction type small-sized electrification amount measuring apparatus, "MODEL 212 HS" manufactured by TREK corporation). The total quantity of electricity Q (unit: + μ C) and the mass M (unit: g) of calcium carbonate attracted were measured with a charged-quantity measuring apparatus. The charge amount of calcium carbonate was calculated according to the formula "charge amount ═ Q/M" (triboelectric charge amount, unit: + μ C/g).

The method of measuring the charge amount of calcium carbonate after the photosensitive layer 102 and calcium carbonate have been rubbed together is described above with reference to fig. 2. The charge amounts of the calcium carbonate of the photoreceptors (P-A2) to (P-A16) and (P-B1) to (P-B4) were measured by the same method as that for the photoreceptor (P-A1) except for changing the following points. In the first step, the coating liquid for photosensitive layer used for producing the photoreceptors (P-A2) to (P-A16) and (P-B1) to (P-B4) was used in place of the coating liquid for photosensitive layer used for producing the photoreceptor (P-A1).

Table 2 shows the calculated charge amounts of calcium carbonate for the photoreceptors (P-A1) to (P-A16) and (P-B1) to (P-B4). The larger the positive charge amount of calcium carbonate, the more easily the calcium carbonate is positively charged to the first photosensitive layer and the second photosensitive layer.

< evaluation of sensitivity characteristics >

The photoreceptors (P-A1) to (P-A16) and (P-B1) to (P-B4) were evaluated for sensitivity characteristics, respectively. Feeling ofThe evaluation of the photometric characteristics was carried out at a temperature of 23 ℃ and a relative humidity of 50% RH. First, the surface of the photoreceptor was charged to +600V using a drum sensitivity tester (manufactured by GENTEC corporation). Then, monochromatic light (wavelength 780nm, half-width 20nm, light energy 1.5. mu.J/cm, wavelength) was extracted from the white light of the halogen lamp using a band-pass filter²). The extracted monochromatic light is irradiated to the surface of the photoreceptor. The surface potential of the photoreceptor after 0.5 second from the end of the irradiation was measured. Measured surface potential as sensitometric potential (V)_LThe unit: + V, hereinafter referred to as "post-exposure potential"). Table 2 shows the measured post-exposure potentials (V) of the photoreceptors_L). And, post-exposure potential (V)_L) A smaller positive value indicates more excellent sensitivity characteristics of the photoreceptor.

< evaluation of image characteristics >

The photoreceptors (P-A1) to (P-A16) and (P-B1) to (P-B4) were evaluated for image characteristics, respectively. The evaluation of the image characteristics was carried out under an RH atmosphere at a temperature of 32.5 ℃ and a relative humidity of 80%. An image forming apparatus (manufactured by Kyowa office information systems Co., Ltd. "monochrome printer FS-1300D") was used as the evaluation equipment. The image forming apparatus employs a non-contact development system, a direct transfer system, and a blade cleaning system. The image forming apparatus includes a gate tube charger as a charging unit. The charging polarity of the charging section is set to positive polarity. The recording medium used was "Jing porcelain office information System Brand paper VM-A4" (size A4) sold by Jing porcelain office information System, Inc. One-component developer (test production sample) was used for the evaluation by the evaluation equipment.

With the evaluation apparatus, image I (image with print coverage of 1%) was continuously printed on 20000 sheets of recording medium under the condition that the rotation speed of the photoreceptor was 168 mm/sec. Next, image II (black solid image of a4 size) was printed on 1 recording medium. The recording medium on which the image II was formed was visually observed, and the number of white dots appearing in the image II was counted. The more minute components (e.g., paper dust) of the recording medium adhering to the photoreceptor, the more the number of white dots in the image II tends to increase. Table 2 shows the number of white dots that appear within image II.

In Table 2, CGM, HTM, ETM, resin and V_LEach represents a charge generator, a hole transporting agent, an electron transporting agent, a binder resin, and a post-exposure potential. In Table 2, X-H₂Pc and Y-TiOPc represent X-type metal-free phthalocyanine and Y-type oxytitanium phthalocyanine, respectively.

[ TABLE 2 ]

The photoreceptors (P-A1) to (P-A16) include a conductive substrate and a single photosensitive layer. The photosensitive layer contains a charge generator, an electron transport agent, and a binder resin. The electron transport agent contains the compound (1). Specifically, the photosensitive layer contains any one of the compounds (1-1) to (1-4) as an electron transporting agent. After the photosensitive layer is rubbed with calcium carbonate, the charge amount of the calcium carbonate is more than +7.0 mu C/g. Therefore, as can be seen from Table 2, the photoreceptors (P-A1) to (P-A16) have a small number of white dots in the formed image, and the occurrence of white dots is suppressed. Further, in these photoreceptors, the occurrence of white spots in the formed image can be suppressed without impairing the sensitivity characteristics of the photoreceptor.

On the other hand, the photosensitive layers of the photoreceptors (P-B1) to (P-B4) do not contain the compound (1). The photosensitive layers of (P-B1) and (P-B2) of the photoreceptor contain the compound (E-1), but the compound (E-1) is not a compound represented by the general formula (1). Specifically, for the compound (E-1), several R in the general formula (1)¹None of 1 represents a halogen atom. The photosensitive layers of (P-B3) and (P-B4) of the photoreceptor contain the compound (E-2), but the compound (E-2) is not a compound represented by the general formula (1).

In the photoreceptors (P-B1) to (P-B4), the charge amount of calcium carbonate after the friction between the photosensitive layer and calcium carbonate was less than + 7.0. mu.C/g. Accordingly, as can be seen from Table 2, the photoreceptors (P-B1) to (P-B4) had a large number of white dots in the formed image, and the occurrence of white dots in the formed image could not be suppressed.

As described above, the photoreceptor according to the present invention can suppress the occurrence of white spots in the formed image. Further, the process cartridge and the image forming apparatus according to the present invention can suppress the occurrence of white spots in the formed image.

Claims

1. An electrophotographic photoreceptor comprising a conductive substrate and a photosensitive layer,

the photosensitive layer is a single layer, and the photosensitive layer is a single layer,

the photosensitive layer contains a charge generator, an electron transporting agent and a binder resin,

the electron transport agent contains a compound represented by the following general formula (1),

the photosensitive layer also contains a hole-transporting agent,

the hole-transporting agent comprises a compound represented by the following general formula (2),

after the photosensitive layer is rubbed with calcium carbonate, the charge amount of the calcium carbonate is more than +7.0 mu C/g,

[ CHEM 1 ]

In the general formula (1) described above,

p represents an integer of 2 to 5 inclusive,

a number of R¹Each independently represents a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms or an acyl group having 2 to 11 carbon atoms,

a number of R¹At least 1 of which represents a halogen atom,

in the general formula (2) described above,

R²¹、R²²、R²³、R²⁴、R²⁵and R²⁶Each independently represents an alkyl group having 1 to 6 carbon atoms or an alkoxy group having 1 to 6 carbon atoms,

r, s, v and w are each independently an integer of 0 to 5,

t and u are each independently an integer of 0 to 4.

2. The electrophotographic photoreceptor according to claim 1,

in the general formula (1) described above,

p represents a number of 2 or 3,

a number of R¹Each independently represents a halogen atom, an alkyl group having 1 to 6 carbon atoms or an acyl group having 2 to 11 carbon atoms,

a number of R¹At least 1 of them represents a halogen atom.

3. The electrophotographic photoreceptor according to claim 1 or 2,

in the general formula (1) described above,

p represents a group of 2 and p represents a group of,

2R¹One of them represents a halogen atom, and the other represents an acyl group having 2 to 11 carbon atoms.

4. The electrophotographic photoreceptor according to claim 1 or 2,

the compound represented by the general formula (1) is a compound represented by the following chemical formula (1-1), (1-2), (1-3) or (1-4),

[ CHEM 2 ]

[ CHEM 3 ]

[ CHEM 4 ]

[ CHEM 5 ]

。

5. The electrophotographic photoreceptor according to claim 1 or 2,

the compound represented by the general formula (1) is a compound represented by the following chemical formula (1-4),

[ CHEM 6 ]

。

6. The electrophotographic photoreceptor according to claim 1 or 2,

the binder resin comprises a polycarbonate resin represented by the following general formula (4),

[ CHEM 7 ]

In the general formula (4) described above,

R⁴¹、R⁴²、R⁴⁵and R⁴⁶Each independently represents a first group, a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms or an aryl group having 6 to 14 carbon atoms,

the first group is a group selected from the group consisting of a halogen atom, an alkyl group having 1 or more halogen atoms and having 1 or more carbon atoms and 6 or less, an alkoxy group having 1 or more halogen atoms and having 1 or more carbon atoms and 6 or less, and an aryl group having 1 or more halogen atoms and having 6 or more carbon atoms and 14 or less,

R⁴¹、R⁴²、R⁴⁵and R⁴⁶At least 1 of which represents said secondA group of the organic light-emitting diode is provided,

R⁴³and R⁴⁴Each independently represents a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms or an aryl group having 6 to 14 carbon atoms,

y represents a cycloalkylene group having 5 to 15 carbon atoms, the cycloalkylene group being a divalent group in which 2 bonds are bonded to 1 carbon atom among carbon atoms forming the cycloalkane,

m and n are each independently a number satisfying the following equations (i) and (ii),

m+n＝1.00……(i)

0.00＜m≤1.00……(ii)。

7. the electrophotographic photoreceptor according to claim 6,

in the general formula (4) described above,

R⁴¹、R⁴²、R⁴⁵and R⁴⁶Each independently represents the first group, a hydrogen atom or an alkyl group having 1 to 6 carbon atoms,

the first group is a group selected from the group consisting of a halogen atom, an alkyl group having 1 or more halogen atoms and having 1 or more carbon atoms and 6 or less, and an aryl group having 1 or more halogen atoms and having 6 or more carbon atoms and 14 or less,

R⁴¹、R⁴²、R⁴⁵and R⁴⁶At least 1 of which represents said first radical,

R⁴³and R⁴⁴Represents a hydrogen atom, and is represented by,

y represents a cycloalkylene group having 5 to 7 carbon atoms.

8. A kind of processing box is disclosed, which comprises a box body,

the electrophotographic photoreceptor according to claim 1 or 2.

9. An image forming apparatus is provided in which a toner cartridge is accommodated in a housing,

comprises an electrophotographic photoreceptor, a charging section, an exposure section, a developing section and a transfer section,

the charging section charges a surface of the electrophotographic photoreceptor,

the exposure section exposes the surface of the charged electrophotographic photoreceptor to form an electrostatic latent image on the surface of the electrophotographic photoreceptor,

the developing section develops the electrostatic latent image into a toner image,

the transfer section transfers the toner image from the electrophotographic photoreceptor to a transfer object,

it is characterized in that the preparation method is characterized in that,

the charging section charges the surface of the electrophotographic photoreceptor to a positive polarity,

the electrophotographic photoreceptor is the electrophotographic photoreceptor described in claim 1 or 2.