JP3194389B2 - Electrophotographic photoreceptor - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photosensitive member, and more particularly, to an electrophotographic photosensitive member containing a specific compound in a photosensitive layer.

[0002]

2. Description of the Related Art Conventionally, inorganic materials such as selenium, cadmium sulfide, and zinc oxide have been used as a photoconductive material of a photoreceptor used in an electrophotographic system.
Here, the term "electrophotographic method" generally means that a photoconductive photoreceptor is first charged in a dark place, for example, by corona discharge, and then subjected to image exposure to selectively dissipate the charge of only the exposed portion. An electrostatic latent image is obtained, and the latent image portion is developed and visualized with fine particles (toner) composed of a coloring material such as a dye or a pigment and a binder such as a polymer substance to form an image. This is one of the image forming methods used.

The basic characteristics required of a photoreceptor in such an electrophotographic method include (1) being able to be charged to an appropriate potential in a dark place, (2) being small in electric charge dissipation in a dark place, (3) Charges can be quickly dissipated by light irradiation.

[0004] The above-mentioned inorganic substances have many advantages and also have various disadvantages. For example, selenium, which is widely used at present, satisfies the above conditions (1) to (3), but the production conditions are difficult, the production cost is high, there is no flexibility, and the selenium is processed into a belt shape. It also has drawbacks in that it is difficult to handle, and is sensitive to heat and mechanical shocks, and requires careful handling. Cadmium sulfide and zinc oxide are used as photoreceptors by dispersing them in a resin as a binder.However, due to mechanical defects such as smoothness, hardness, tensile strength, and abrasion resistance, they are repeatedly used as they are. Can not be used.

In recent years, electrophotographic photoreceptors using various organic substances have been proposed to eliminate the disadvantages of these inorganic substances, and some of them have been put to practical use. For example, a photoreceptor comprising poly-N-vinylcarbazole and 2,4,7-trinitrofluoren-9-one (U.S. Pat.
84237), a photoreceptor obtained by sensitizing poly-N-vinylcarbazole with a pyrylium salt-based dye (described in JP-B-48-25658), and a photoreceptor containing an organic pigment as a main component (see JP-B-48-25658). JP-A-47-37543), a photoreceptor containing a eutectic complex composed of a dye and a resin as a main component (described in JP-A-47-10735), and dye-sensitized triphenylamine compound. (US Pat. No. 3,180,730), a photoreceptor using an amine derivative as a charge transport material (JP-A-57-195254), and poly-N-vinylcarbazole and an amine derivative as charge transport materials Photoreceptor used (Japanese Patent Laid-Open No. 58-11
55, a photoconductor using a benzidine compound among polyfunctional tertiary amine compounds as a photoconductive material (US Pat. No. 3,265,496, JP-B-39-11546, JP-A-53-27033). ). Although these photoreceptors have excellent properties and are considered to be of high practical value, in electrophotography, considering various requirements for photoreceptors, these requirements are still insufficient. In fact, it is not possible to obtain anything satisfying the above conditions.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to provide a photoreceptor which can solve the above-mentioned various disadvantages of the conventional photoreceptor and can sufficiently satisfy the conditions required in electrophotography. It is in. It is a further object of the present invention to provide an electrophotographic photoreceptor which is easy to manufacture, relatively inexpensive, and has excellent durability.

[0007]

According to the present invention, at least one dipyrenylamine derivative represented by the following general formula (I) is contained on a conductive support as an active ingredient, and charge generation is performed. As a substance, the following formula (i):
(Ii) or (iii) (Chemical formula 6, Chemical formula 7, or Chemical formula 8) Chemical formula 2,
Selected from the group consisting of compounds represented by Formula 3 or 4
An electrophotographic photoreceptor comprising a photosensitive layer containing any one of the above compounds is provided.

Embedded image (In the formula, R represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group.)

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[0008] Jipireniruamin derivative represented by the general formula to be contained in the photosensitive layer (I) in the present invention is a compound represented by general formula (II) (Formula 9)

Embedded image (Wherein X represents a halogen atom such as bromine or iodine) and a halogenopyrene represented by the general formula (III)
( Formula 10 )

[Image Omitted] H_TwoNR(III)  (Wherein R is as defined above)
Or a compound of the general formula (IV) (Chemical formula 11)

Embedded image In a di (1-pyrenyl) amine represented by the general formula (V) (Formula 12)

XR is produced by reacting with a halide represented by the formula: XR (V) (wherein X and R are as defined above).

In the general formulas (I), (II) and (V), R is a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group. Is a phenyl group, a biphenyl group,
Examples include a non-fused carbocyclic aromatic group such as a terphenyl group and a fused polycyclic hydrocarbon group or a heterocyclic aromatic hydrocarbon group.

In this case, the fused polycyclic hydrocarbon group preferably has 18 or less carbon atoms forming a ring, for example, a pentalenyl group, an indenyl group, a naphthyl group,
Azulenyl group, heptalenyl group, biphenylenyl group, a
s-indacenyl group, fluorenyl group, S-indacenyl group, acenaphthenyl group, preadenyl group, acenaphthenyl group, phenalenyl group, phenanthryl group, anthryl group, fluoranthenyl group, acephenanthrenyl group, aceanthrenylenyl, triphenylenyl Group, pyrenyl group, chrysenyl group, naphthacenyl group and the like.

The heterocyclic aromatic hydrocarbon group includes the following groups. Thienyl group, furyl group, 2
-Pyridyl group, 4-pyridyl group, 3-indolyl group, 2
- quinolyl group, 3,4 Benzupiraniru group, acridinyl group, a thiazolyl group, benzo thiazolo group, 9-methyl-carbazolyl group, 9-ethyl carbazolyl group, 9-propyl carbazolyl group, 9 Phenylcarbazolyl group,
9-tolylcarbazolyl group, 4-pyrazolyl group and the like,

The aryl groups include those having the following substituents.

(1) Halogen atom, cyano group, nitro group (2) Alkyl group, preferably C ₁ -C _12, especially C ₁
To C ₈ , more preferably a C _{1 to} C ₄ linear or branched alkyl group, and these alkyl groups are furthermore a hydroxyl group, a cyano group, a C _{1 to} C ₄ alkoxy group, a phenyl group or a halogen atom, C ₁ alkyl or C ₁ ~ of -C ₄
It may contain a phenyl group substituted by a C ₄ alkoxy group. Specifically, methyl, ethyl, n-propyl, i-propyl, t-butyl, s-butyl, n-butyl, i-butyl, 2-hydroxyethyl, 2-cyanoethyl Group, 2-ethoxyethyl group, 2
-Methoxyethyl group, benzyl group, 4-chlorobenzyl group, 4-methylbenzyl group, 4-methoxybenzyl group,
4-phenylbenzyl group and the like.

(3) alkoxy group (-OR ₁ ); R ₁ represents an alkyl group defined in (2). Specifically, methoxy group, ethoxy group, n-propoxy group, i-propoxy group, t-butoxy group, n-butoxy group, s-butoxy group, i-butoxy group, 2-hydroxyethoxy group, 2
-A cyanoethoxy group, a benzyloxy group, a 4-methylbenzyloxy group and the like.

(4) Aryloxy group: Examples of the aryl group include a phenyl group and a naphthyl group. This is C ₁
Alkoxy group -C _4, alkyl group, or a halogen atom C ₁ -C ₄ may contain a substituent group. Specifically, a phenoxy group, a 1-naphthyloxy group, a 2-naphthyloxy group, a 4-methylphenoxy group, a 4-methoxyphenoxy group, a 4-chlorophenoxy group, a 6-methyl-2
-Naphthyloxy group and the like.

(5) Alkyl mercapto group (-S
R ₁ ); R ₁ represents an alkyl group defined in (2). Specific examples include a methylthio group, an ethylthio group, a phenylthio group, and a p-methylphenylthio group.

[0017] R ₂ / (6) -N; (wherein, R ₂ and R ₃ each independently represent a hydrogen atom, a defined \ R ₃ was an alkyl group, or an aryl group (2), as the aryl group Is, for example, a phenyl group, a biphenylyl group or a naphthyl group. These are a C ₁ -C ₄ alkoxy group, a C ₁ -C ₄
An alkyl group of ₁ to ₄ or a halogen atom may be contained as a substituent. R ₂ and R ₃ may form a ring together. Further, a ring may be formed together with a carbon atom on the aryl group. ) Specifically, an amino group, a diethylamino group,
Examples thereof include an N-methyl-N-phenylamino group, an N, N-diphenylamino group, an N, N-di (p-tolyl) amino group, a dibenzylamino group, a piperidino group, a morpholino group, and a uroridyl group.

(7) An alkylenedioxy group or an alkylenedithio group such as a methylenedioxy group or a methylenedithio group.

In the general formulas (I), (III) and (V), when R is an alkyl group, specific examples thereof include the same as the specific examples of the (2) alkyl group described for the aryl group. . Specific examples of R include the same as the specific examples of the substituents similarly described for the aryl group.

Hereinafter, representative examples of the dipyrenylamine derivative represented by the general formula (I) are shown.

[Table 1- (1)]

[Table 1- (2)]

[Table 1- (3)]

The photoreceptor of the present invention comprises one or more of the above-mentioned dipyrenylamine derivatives in the photosensitive layer 2 (2 ′,
2 '', 2 '''or2'''') to the Ru is contained co
In addition, the following formulas (i), (ii) or
(Iii) Chemical formula represented by Chemical Formula 13, Chemical Formula 14, or Chemical Formula 15
But in which it was contained compound, 1 by way of the application of these Jipireniruamin derivatives, 2, 3, 4
Alternatively, it can be used as shown in FIG.

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The photosensitive member shown in FIG. 1 has a conductive support 1 on which a photosensitive layer 2 made of a dipyrenylamine derivative, a sensitizing dye and a binder (binder resin) is provided. The dipyrenylamine derivative here acts as a photoconductive substance, and the generation and transfer of charge carriers required for light decay are performed via the dipyrenylamine derivative. However,
Since the dipyrenylamine derivative has almost no absorption in the visible region of light, it is necessary to add a sensitizing dye having absorption in the visible region for sensitization in order to form an image with visible light.

The photosensitive member shown in FIG. 2 has a photosensitive layer 2 'in which a charge generating material 3 is dispersed on a conductive support 1 in a charge transporting medium 4 comprising a dipyrenylamine derivative and a binder.
Is provided. The dipyrenylamine derivative here forms a charge transport medium with a binder (or a binder and a plasticizer), while the charge generating material 3 (a charge generating material such as an inorganic or organic pigment) generates charge carriers.
In this case, the charge transport medium 4 is mainly responsible for receiving and transporting charge carriers generated by the charge generating substance 3. In this photoreceptor, the basic condition is that the charge generation substance and the dipyrenylamine derivative do not overlap in the absorption wavelength region mainly in the visible region. This is because it is necessary to transmit light to the surface of the charge generating material 3 in order to efficiently generate charge carriers in the charge generating material 3. The dipyrenylamine derivative represented by the general formula (I) has almost no absorption in the visible region, generally absorbs light in the visible region, and is particularly effective as a charge transport material when combined with the charge generation material 3 which generates a charge carrier. The feature is that it works.

The photosensitive member shown in FIG. 3 is a photosensitive layer 2 '' comprising a conductive support 1 and a charge generating layer 5 mainly composed of a charge generating substance 3 and a charge transporting layer 4 containing a dipyrenylamine derivative. Is provided. In this photoreceptor, the light transmitted through the charge transport layer 4 reaches the charge generation layer 5 and charge carriers are generated in that region. On the other hand, the charge transport layer 4 receives injection of the charge carriers and transports them. The generation of charge carriers required for light attenuation is based on the charge generation material 3
The transport of the charge carriers is performed in the charge transport layer 4 (mainly the dipyrenylamine derivative works).
Such a mechanism is the same as that described for the photoconductor shown in FIG.

The photosensitive member shown in FIG.
And the charge transport layer 4 containing the dipyrenylamine derivative is reversed in the stacking order, and the mechanism for generating and transporting the charge carriers can be the same as described above. In this case, a protective layer 6 can be provided on the charge generation layer 5 in the fifth manner in consideration of mechanical strength.

To actually produce the photoreceptor of the present invention, FIG.
In the case of the photoreceptor shown in (1), one or two or more dipyrenylamine derivatives are dissolved in a solution in which a binder is dissolved, and a solution containing a sensitizing dye is added thereto. , And dried to form the photosensitive layer 2.

The thickness of the photosensitive layer is 3 to 50 μm, preferably 5 to 20 μm. The amount of the dipyrenylamine derivative in the photosensitive layer 2 is 30 to 70% by weight, preferably about 50% by weight, and the amount of the sensitizing dye in the photosensitive layer 2 is 0.1 to 5% by weight, preferably 0.1 to 5% by weight. 5 to 3% by weight. Examples of sensitizing charges include brilliant green, Victoria Blue B, methyl violet, crystal violet, triarylmethane dyes such as Acid Violet 6B, rhodamine B, rhodamine 6G, rhodamine G extra, eosin S, erythrosin, rose bengal and fluorescein. Xanthene dyes, such as
Thiazine dyes such as methylene blue, cyanine dyes such as cyanine, 2,6-diphenyl-4- (N, N-
Pyrylium dyes such as dimethylaminophenyl) thiapyrylium perchlorate and benzopyrylium salts (described in JP-B-48-25658). These sensitizing dyes may be used alone or in combination of two or more.

Further, in order to produce the photoreceptor shown in FIG. 2, fine particles of the charge generating substance 3 are dispersed in a solution in which one or more dipyrenylamine derivatives and a binder are dissolved, and this is converted into a conductive material. What is necessary is just to apply | coat on the support body 1, and to dry and to form the photosensitive layer 2 '.

The thickness of the photosensitive layer 2 'is 3 to 50 μm, preferably 5 to 20 μm. The amount of the dipyrenylamine derivative in the photosensitive layer 2 'is 10 to 95% by weight, preferably 30 to 90% by weight, and the amount of the charge generating substance 3 in the photosensitive layer 2' is 0.1 to 50% by weight. Preferably it is 1 to 20% by weight. Examples of the charge generating substance 3 include inorganic pigments such as selenium, selenium-tellurium, cadmium sulfide, cadmium sulphide-selenium, and α-silicon. (CI 21200), CI Acid Red 52 (CI 45100), CI Basic Red 3 (CI45210), azo pigments having a carbazole skeleton (described in JP-A-53-95033), azo pigments having a distyrylbenzene skeleton ( JP-A-53-133445), azo pigments having a triphenylamine skeleton (described in JP-A-53-132347), and azo pigments having a dibenzothiophene skeleton (described in JP-A-54-21728) , Oxadia Azo pigments having Lumpur skeleton (JP 54-12742
Azo pigments having a fluorenone skeleton (described in JP-A-54-22834), azo pigments having a bisstilbene skeleton (described in JP-A-54-17733), distyryl oxadiazole An azo pigment having a skeleton (described in JP-A-54-2129) and an azo pigment having a distyrylcarbazole skeleton (described in JP-A-52-129)
Azo pigments such as C.I. Pigment Blue 16 (CI74100), such as C.I. Pigment Blue 16 (CI74100), C.I.
And perylene-based pigments such as Argo Scarlet B (manufactured by Bayer), Indance Scarlet R (manufactured by Bayer), and the like. These charge generating substances may be used alone or in combination of two or more.

Further, in order to produce the photoreceptor shown in FIG. 3, a charge generating substance is vacuum-deposited on one or more conductive supports, or an appropriate binder in which fine particles 3 of the charge generating substance are dissolved in a binder if necessary. Coating and drying, and further, if necessary, surface finishing and film thickness adjustment by a method such as buffing, and the like.
Is formed, and a solution in which one or more dipyrenylamine derivatives and a binder are dissolved is applied thereon and dried to form the charge transport layer 4. Here, the charge generating material used for forming the charge generating layer 5 is the photosensitive layer 2 '.
Is the same as that described in the description.

The thickness of the charge generation layer 5 is 5 μm or less, preferably 2 μm or less, and the thickness of the charge transport layer 4 is 3 to 50 μm.
μm, preferably 5 to 20 μm is suitable. In the type in which the charge generation layer 5 has the fine particles 3 of the charge generation layer material dispersed in a binder, the ratio of the fine particles 3 of the charge generation material to the charge generation layer 5 is preferably 10 to 95% by weight. Is about 50 to 90% by weight. The charge transport layer 4
Is 10 to 95% by weight, preferably 3% by weight.
0 to 90% by weight. In order to prepare the photoreceptor shown in FIG. 4, a solution in which a dipyrenylamine derivative and a binder are dissolved is coated on the conductive support 1 and dried to form the charge transport layer 4.
Is formed on the charge transport layer, and a dispersion of fine particles of the charge generation layer material dispersed in a solvent in which a binder is dissolved, if necessary, is applied by a method such as spray coating and dried to form the charge generation layer 5. May be formed. The amount ratio of the charge generation layer or the charge transport layer is the same as that described in FIG. The photoreceptor shown in FIG. 5 can be prepared by further forming a protective layer 6 on the thus-obtained photoreceptor charge generation layer 5 by a method such as spray coating. As the resin used here, a binder described later can be used.

In the production of any of these photoconductors, a metal plate or a metal foil such as aluminum, a plastic film on which a metal such as aluminum is vapor-deposited, or a paper subjected to a conductive treatment is used for the conductive support 1. Can be Examples of the binder include condensation resins such as polyamide, polyurethane, polyester, epoxy resin, polyketone, and polycarbonate; and vinyl polymers such as polyvinyl ketone, polystyrene, poly-N-vinylcarbazole, and polyacrylamide. All insulating and adhesive resins can be used. If necessary, a plasticizer is added to the binder. Examples of such a plasticizer include halogenated paraffin, polychlorinated biphenyl, dimethylnaphthalene, and dibutylphthalate.

Further, the photosensitive member obtained as described above may be provided with an adhesive layer or a barrier layer between the conductive support and the photosensitive layer, if necessary. Materials used for these layers include polyamide, nitrocellulose,
Aluminum oxide and the like, and the film thickness is preferably 1 μm or less. To make a copy using the photoreceptor of the present invention,
After the photosensitive surface is charged and exposed, development is performed and, if necessary, transfer to paper or the like. The photoreceptor of the present invention has excellent advantages such as high sensitivity and high flexibility.

[0034]

The present invention will be described below with reference to examples. In the following examples, all parts are parts by weight.

[Synthesis of Compound of General Formula (I)] [Compound No. Synthesis Example 9 ] 1.07 g (10.0 mmol) of p-toluidine, 1-
6.56 g (20.0 mmol) of iodopyrene, 5.53 g of potassium carbonate, 0.64 g of copper powder and 50 ml of nitrobenzene were stirred at 207 ° C. for 6.5 hours while azeotropically dehydrating with an ester tube under a nitrogen stream. After cooling to room temperature, the mixture was filtered using Celite, and the filtrate was concentrated under reduced pressure to distill off nitrobenzene. Chloroform was added to the obtained residue, the chloroform layer was washed with water, dried over magnesium sulfate, and concentrated under reduced pressure to obtain a dark brown oil. This was treated with a silica gel column [eluent; mixed solvent of toluene / n-hexane (1: 2)], recrystallized from a mixed solvent of ethanol / DMF, and N, N-di (1-
(Pyrenyl) -P-toluidine (Compound No. 9) 1.3
3 g (26.2% yield) were obtained. Melting point: 272.5-2
73.5 ° C. Elemental analysis values were as follows, as C ₃₉ H ₂₅ N.

[0036]Comparative Example 1  Diane blue (C.I.
Toblue 25, CI21180) 76 parts, polyester
2% Tet of resin (Byron 200, manufactured by Toyobo Co., Ltd.)
1260 parts of a lahydrofuran solution and tetrahydrofura
3700 parts were pulverized and mixed in a ball mill.
Spray liquid is made of aluminum base
Doctor blade on the aluminum surface of the conductive support
Apply and dry naturally to generate a charge of about 1μm thick
A layer was formed. On the other hand, as charge transport substances,
Example No. 2 dipyrenylamine derivative, polycarbonate
Nate resin (Panlite K1300, manufactured by Teijin Limited) 2
And 16 parts of tetrahydrofuran
After that, a doctor blade is placed on the charge generation layer.
At 80 ° C. for 2 minutes, then at 120 ° C. for 5 minutes.
Dry for 20 minutes to form a charge transport layer with a thickness of about 20 μm
And the photosensitive member No. 1 was created.

Comparative Example 26And Examples 1 to27  Charge-generating substances and charge-transporting substances (dipyrenylamine-induced
Example 1 except that (conductor) was changed to that shown in Table 2.
In the same way, the photosensitive member No. 2-33 were created.

[Table 2- (1)]

[Table 2- (2)]

[Table 2- (3)]

[Table 2- (4)]

[Table 2- (5)]

The photosensitive member no. 1-33
Using a commercially available electrostatic copying paper tester (type SP428, manufactured by KK Kawaguchi Electric Works), a corona discharge of -6 KV or +6 KV was performed for 20 seconds, and the surface was charged in a dark place for 20 seconds. The potential Vpo (volt) was measured, and then a tungsten lamp light was applied so that the illuminance on the photoreceptor surface became 4.5 lux, and the time (second) until the surface potential became 1/2 of Vpo was obtained. , Exposure amount E
1/2 (look-seconds) was calculated. Table 3 shows the results.

After charging each of the above photoreceptors using a commercially available electrophotographic copying machine, the photosensitive members are irradiated with light through the original drawing to form an electrostatic latent image, and developed using a dry developer. When the obtained image (toner image) was electrostatically transferred onto plain paper and fixed, a clear transfer image was obtained. Similarly, when a wet type developer was used as the developer, a clear transfer image was obtained.

[Table 3- (1)]

[Table 3- (2)]

[Table 3- (3)]

[Effects] The photoreceptor of the present invention is not only excellent in photosensitive characteristics but also has high strength against heat and mechanical shock and can be manufactured at low cost.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a typical electrophotographic photosensitive member according to the present invention, which is enlarged in a thickness direction.

FIG. 2 is a cross-sectional view of another typical electrophotographic photosensitive member according to the present invention, which is enlarged in a thickness direction.

FIG. 3 is a cross-sectional view enlarged in a thickness direction of still another typical electrophotographic photosensitive member according to the present invention.

FIG. 4 is a cross-sectional view enlarged in a thickness direction of another electrophotographic photosensitive member according to the present invention.

FIG. 5 is a cross-sectional view enlarged in a thickness direction of still another electrophotographic photosensitive member according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Conductive support 2, 2 ', 2 ", 2"', 2 '"" ... Photosensitive layer 3 ... Charge generation material 4 ... Charge transport medium or charge transport layer 5 ... Charge generation layer 6 ... Protection layer

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Hiroshi Adachi 1-3-6 Nakamagome, Ota-ku, Tokyo Inside Ricoh Co., Ltd. (56) References JP-A-2-195880 (JP, A) JP-A Sho 63-206755 (JP, A) JP-A-63-206754 (JP, A) JP-A-4-275262 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G03G 5/06

Claims (1)

(57) [Claims] 1. A conductive support containing, as an active ingredient, at least one dipyrenylamine derivative represented by the following general formula (I) (formula 1) as an active ingredient, and the following formulas (i) and (ii) as charge generating substances: ) Or (iii) (Formula 2,
Selected from the group consisting of compounds represented by formula 3 or 4)
An electrophotographic photoconductor comprising a photosensitive layer containing any one of the above compounds . Embedded image (In the formula, R represents a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group.) Embedded image Embedded image