JPS6255656B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an electrophotographic photoreceptor containing a divinylbenzene compound as an active ingredient in the photosensitive layer. Conventionally, photoconductive materials for photoreceptors used in electrophotography include inorganic materials such as selenium, cadmium sulfide, and zinc oxide. The "electrophotographic method" referred to here generally involves first charging a photoreceptor in a dark place by corona discharge, and then exposing it to imagewise light to selectively discharge the charge only in the exposed areas, thereby forming an electrostatic latent image. This is one of the image forming methods in which an image is formed by visualizing this latent image area with a developer containing a coloring agent called a toner and electrostatic fine particles made of a binder resin. The basic characteristics required of a photoreceptor in such electrophotography are 1) the ability to be charged to an appropriate potential in a dark place, and 2)
Examples include the fact that there is little charge discharge in a dark place, and the charge is rapidly released by three-light irradiation. Although the conventionally used inorganic materials have many advantages, they also have various disadvantages. For example, selenium, which is currently widely used, fully satisfies conditions 1 to 3 above, but it has strict manufacturing conditions, increases manufacturing costs, and is not flexible, so it cannot be processed into a belt shape. It also has drawbacks such as being difficult and sensitive to heat and mechanical shock, requiring careful handling. Cadmium sulfide and zinc oxide are used dispersed in binding resins, but they have mechanical drawbacks such as smoothness, hardness, tensile strength, and abrasion resistance.
It cannot withstand repeated use as it is. In recent years, electrophotographic photoreceptors using various organic materials have been proposed in order to eliminate the drawbacks of these inorganic materials, and some of them have been put into practical use. For example, poly-N-vinylcarbazole and 2,4,7-
A combination of trinitro-9-fluorenone (U.S. Pat. No. 3,484,237), a sensitized poly-N-vinylcarbazole with a pyrylium salt dye (Japanese Patent Publication No. 48-25658), and an organic pigment as a main component. (Japanese Unexamined Patent Publication No. 47-37543), and one whose main component is a eutectic complex consisting of a dye and a resin (Japanese Unexamined Patent Publication No. 10735/1982). These photoreceptors certainly have excellent characteristics and are considered to be of high practical value, but considering the various requirements for photoreceptors from the viewpoint of electrophotographic processes, it is still difficult to fully meet these requirements. The reality is that we are not getting anything that satisfies us. On the other hand, although these excellent photoreceptors differ slightly depending on the purpose or manufacturing method, they generally exhibit excellent characteristics by using an excellent photoconductive material. As a result of researching this type of photoconductive substance from the above viewpoints, the present inventors discovered that a divinylbenzene compound represented by the following general formula works effectively as a photoconductive substance for electrophotographic photoreceptors. did. That is, as will be described later, it has been discovered that by combining the compound of this general formula with various materials, it is possible to provide a photoreceptor that has unexpected effects and is surprisingly useful in a wide range of aspects. (In the formula, R is a carbazolyl group, pyridyl group, thienyl group, indolyl group, furyl group, or a substituted or unsubstituted phenyl group, styryl group, naphthyl group, or anthryl group, and these substituents are dialkylamino groups) , an alkyl group, an alkoxy group, a carboxy group or an ester thereof, a halogen atom, a cyano group, an aralkylamino group, an amino group, a hydroxy group, a nitro group, and an acetylamino group.) In the present invention, The divinylbenzene compound of the general formula used is prepared according to the method of W. Stilz et al. (German patent no.
1124949), high purity and high yield can be obtained by stirring tetraalkyl o-xylylene diphosphonate and aldehydes at a temperature of 10 to 180°C for 15 minutes to 3 hours in the presence of a strong alkali. It can be obtained with Alternatively, the so-called Wittig reaction using phosphine by CEGriffin et al. [J.Org.Chem. 27 , 1627
(1962)]. A specific example of the divinylbenzene compound having the above general formula obtained in this manner is shown below by a structural formula. During the ceremony teeth

It is abbreviated as [Formula].

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[Table] The photoreceptor of the present invention contains the above-mentioned divinylbenzene compounds, and can take the forms shown in FIGS. 1 to 3 depending on how these divinylbenzene compounds are applied. The photoreceptor shown in FIG. 1 has a photosensitive layer 2 formed on a conductive support 1, comprising the divinylbenzene compound, a sensitizing dye, and a binding resin. The photoreceptor shown in FIG. 2 has a photosensitive layer 2' on a conductive support 1 in which a charge carrier generating substance 3 is dispersed in a charge transfer medium 4 made of the divinylbenzene compound and a binding resin.
It has been established. Further, the photoreceptor shown in FIG. 3 has a photosensitive layer 2'' formed on a conductive support 1, comprising a charge carrier generation layer 5 mainly composed of a charge carrier generation substance 3 and a charge transfer layer 4 containing the divinylbenzene compound. In the photoreceptor shown in Fig. 1, the divinylbenzene compound acts as a photoconductive substance, and the generation and transfer of charge carriers necessary for light attenuation occur through this divinylbenzene compound. Since most compounds have no absorption in the visible range, depending on the light source used, it is necessary to sensitize with a sensitizing dye that has absorption in the visible range.In the case of the photoreceptor shown in Figure 2, this divinyl Benzene compounds together with binders (and optionally plasticizers) form a charge transport medium, while charge carrier generating substances such as inorganic or organic pigments generate charge carriers. The carrier generating substance has the ability to accept and move the generated charge carriers.The basic condition here is that the absorption wavelength regions of the charge carrier generating substance and the divinylbenzene compound do not overlap each other, mainly in the visible range. This is because in order to efficiently generate charge carriers in a charge carrier generating material, it is necessary to transmit light to the surface of the charge carrier generating material.The divinylbenzene compound of the present invention absorbs almost nothing in the visible range. When combined with a charge carrier-generating substance that absorbs light in the visible region and generates charge carriers, it works particularly effectively as a charge transfer medium. The light transmitted through the transfer layer 4 reaches the charge carrier generation layer 5, where charge carriers are generated, while the charge transfer medium layer receives charge carriers and moves them. The mechanism in which the charge carriers necessary for light attenuation are generated by a charge carrier generating substance, and the charge carriers are moved by a charge transfer medium (mainly the divinylbenzene compound of the present invention acts) is the same as in the case of the photoreceptor shown in Figure 2. Similarly, the divinylbenzene compound acts as a charge transfer substance here. To prepare the photoreceptor shown in Figure 1, the divinylbenzene compound is dissolved in a binder solution, and if necessary, a sensitizing dye is added The added liquid may be coated on the conductive support 1 and dried to form the photosensitive layer 2. To make the photoreceptor shown in FIG.
The photosensitive layer 2' may be formed by dispersing the fine particles in a solution containing the divinylbenzene compound and the binder, coating the conductive support 1 and drying the dispersed particles. In the case of the photoreceptor shown in FIG. 3, the charge carrier generating substance 3 (a) is vacuum-deposited on the conductive support 1, or the fine particles of the charge carrier generating substance 3 (b) are placed in a solution containing a binder dissolved therein. The charge carrier generating layer 5 is formed by dispersing, applying and drying the layer, and if necessary, finishing the surface by a method such as buffing or adjusting the thickness, and then applying the divinylbenzene compound and crystals thereon. The charge transfer layer 4 may be formed by applying and drying a solution containing an adhesive. Application is carried out by conventional means, such as a doctor blade or wire bar. In the above photoreceptors, the thickness of the photosensitive layer is about 3 to 50 μm, preferably 5 to 50 μm for those shown in FIGS. 1 and 2.
20μ is appropriate. In addition, in the case of the one shown in FIG. 3, the thickness of the charge carrier generation layer is 0.05 to 20μ or less, preferably 0.1
~5μ and the thickness of the charge transport layer is about 3-50μ, preferably 5-20μ. In the photoreceptor shown in FIG. 1, the appropriate proportion of the divinylbenzene compound in the photosensitive layer is 30 to 70%, preferably about 50%, of the weight of the photosensitive layer. The amount of the sensitizing dye used to impart photosensitivity in the visible region is 0.1 to 5%, preferably 0.5 to 3%, based on the weight of the photosensitive layer. Next, the proportion of the divinylbenzene compound in the photosensitive layer shown in FIG. It is 20% by weight. Further, in the photoreceptor shown in FIG. 3, the proportion of the divinylbenzene compound in the charge transfer layer is 10 to 95% by weight, preferably 30 to 90% by weight, as in the case of the photoreceptor shown in FIG. In addition, the first
In any of the photoreceptors shown in FIG. 3, a plasticizer can be used together with a binder. In the photoreceptor of the present invention, as the conductive support, an aluminum metal plate or metal foil, a plastic film on which a metal such as aluminum is vapor-deposited, or paper or plastic film subjected to conductive treatment are used. 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. Any adhesive resin can be used. Examples of the plasticizer include halogenated paraffin, polychlorinated biphenyl, dimethylnaphthalene, and dibutyl phthalate. In addition, the sensitizing dyes used in the photoreceptor shown in FIG.
Xanthene dyes such as 6G, Rhodamine G Extra, Eosin S, Erythrosin, Rose Bengal, Fluorethcene; Thiazine dyes such as methylene blue; Cyanine dyes such as cyanine;
Examples include pyrylium dyes such as 2,6-diphenyl-(N,N-dimethylaminophenyl)thiapyrylium perchlorate and benzopyrylium salts described in Japanese Patent Publication No. 48-25658. The charge generating substance used in FIGS. 2 and 3 is a pigment capable of generating charge carriers by irradiation with light, and it is particularly effective to use, for example, the following azo pigment. Azo pigments having a carbazole skeleton (for example, described in Japanese Patent Application No. 52-8740 or 52-8741) Azo pigments having a styrylstilbene skeleton (for example, described in Japanese Patent Application No. 52-48859) Azo pigments having a triphenylamine skeleton Pigments (for example, described in Japanese Patent Application No. 52-45812) Azo pigments having a dibenzothiophene skeleton (for example, described in Japanese Patent Application No. 52-86255) Azo pigments having an oxadiazole skeleton (for example, described in Japanese Patent Application No. 52-86255) -77155) Azo pigments having a fluorenone skeleton (for example, described in Japanese Patent Application No. 52-87351) Azo pigments having a stilbene skeleton (for example, described in Japanese Patent Application No. 52-81790) Distyryloxadiazole skeleton (For example, described in Japanese Patent Application No. 52-66711) Azo pigments having a distyrylcarbazole skeleton (For example, described in Japanese Patent Application No. 52-81791) In addition to these azo pigments, generally The following known substances can also be used as charge carrier generating pigments. For example, selenium, selenium
Inorganic pigments such as tellurium, cadmium sulfide, cadmium-selenium sulfide, and organic pigments include, for example, seaweed.
Eye pigment blue 25 (color index
Azo pigments such as CI Pigment Red 41 (CI21200), CI Pigment Red 52 (CI45100), CI Basic Cred 3 (CI45210), CI Pigment Blue 16 Phthalocyanine pigments such as (CI74100), Sea Butt Brown 5
Indigo pigments such as (CI73410), C.I.Bath Toledo (CI73030), C.I.Vacit Red 23
(CI71130), Sea Eye Battled 32
(CI71135), CI Battled 29
Examples include organic pigments such as perylene pigments such as (CI71140). In any of the photoreceptors obtained as described above, an adhesive layer or a barrier layer can be provided between the conductive support and the photosensitive layer. Suitable materials for these layers include polyamide, nitrocellulose, aluminum oxide, etc., and the layer thickness is preferably about 0.01 to 1 μm. To perform copying using the photoreceptor of the present invention, the surface of the photosensitive layer is charged and exposed by a conventional method, and then developed, and if necessary, the image is transferred to a transfer paper such as high-quality paper. The photoreceptor of the present invention generally has excellent advantages such as high sensitivity and flexibility. Examples are shown below. All parts are by weight. Example 1 98 parts of tetrahydrofuran were added to 2 parts of Diane Blue (CI21180), and the mixture was pulverized and mixed in a ball mill to obtain a charge carrier-generating pigment dispersion. This is made of aluminized polyester film (thickness approx.
75μ) using a doctor blade and air-dried to form a charge carrier generation layer with a thickness of 1μ. Next, a charge transfer layer forming liquid obtained by mixing 2 parts of the divinylbenzene compound represented by Compound No. 3, 3 parts of polycarbonate (Panlite L manufactured by Teijin) and 45 parts of tetrahydrofuran was applied to the above charge carrier generation layer using a doctor. Apply using a blade,
The photoreceptor of the present invention was prepared by drying at 100° C. for 10 minutes to form a charge transfer layer with a thickness of 9 μm. This photoreceptor was tested using an electrostatic copying paper tester (KK Kawaguchi Electric Seisakusho, SP428 model).
After applying 6KV corona discharge for 20 seconds to make it negatively charged, leave it in a dark place for 20 seconds, and then measure the surface potential.
Measure Vpo (V), then irradiate the surface with light using a tungsten lamp at an illuminance of 20 lux, and calculate the time (seconds) it takes for the surface potential to become 1/2 of Vpo during exposure. The quantity E1/2 (lux seconds) was obtained. The result is Vpo=1250V, E1/
2 = 3.5 lux seconds. Example 2

[Table] A charge carrier-generating pigment dispersion is obtained by pulverizing and mixing the liquid in a ball mill. This was applied onto a polyester film deposited with aluminum using a doctor blade, and dried for 5 minutes in a dryer at 80° C. to form a charge carrier generation layer with a thickness of 1 μm. A charge transfer layer forming liquid obtained by mixing 2 parts of the divinylbenzene compound represented by Compound No. 7, 3 parts of polycarbonate (Panlite L), and 45 parts of tetrahydrofuran was applied onto the charge carrier generation layer using a doctor blade. The photoreceptor of the present invention was prepared by coating the photoreceptor using a photoreceptor and drying it at 100° C. for 10 minutes to form a charge transfer layer with a thickness of 10 μm. This photoreceptor was negatively charged in the same manner as in Example 1, and Vpo and E1/2 were measured.
Vpo=975V, E1/2=3.5 Lux・sec. Example 3 Same as Example 2, but as a charge carrier generating pigment When using divinylbenzene compound represented by compound No. 25 as a charge transfer agent,
Vpo=1320V, E1/2=2.5 Lux・sec. Example 4 In the same manner as in Example 2, as a charge carrier generating pigment When using divinylbenzene compound represented by compound No. 32 as a charge transfer agent,
Vpo=1050V, E1/2=1.5 Lux・sec. Next, the photoreceptors obtained in Examples 1 to 4 were negatively charged using a commercially available copying machine, and then light was irradiated through the original image to form an electrostatic latent image, followed by dry development with positively charged toner. The image was developed using a chemical agent, and the image was electrostatically transferred to high-quality paper and fixed to obtain a clear image. A similarly clear image was obtained when a wet type developer was used as the developer. Example 5 On an aluminum plate with a thickness of about 300 μm, selenium was vacuum-deposited to a thickness of 1 μm to form a charge carrier generation layer. Next, 2 parts of a divinylbenzene compound represented by Compound No. 19, 3 parts of a polyester resin (manufactured by DuPont, Polyester Adhesive 49000)
A charge transfer layer forming solution was prepared by mixing 1 part and 45 parts of tetrahydrofuran, and this was applied onto the above charge carrier generation layer (selenium vapor deposition layer) using a doctor blade, air-dried, and then dried under reduced pressure. A charge transfer layer having a thickness of 10 .mu.m was formed thereon to obtain a photoreceptor of the present invention. This photoconductor was prepared in the same manner as in Example 1, and Vpo
and E1/2 were measured, Vpo=990V, E
1/2 = 4.0 lux seconds. Example 6 Perylene pigment in place of selenium in Example 5 is vacuum deposited to a thickness of 0.3μ to form a charge carrier generation layer. Next, a photoreceptor was prepared in the same manner as in Example 5 except that the charge transfer agent was replaced with a divinylbenzene compound represented by compound No. 33, and Vpo=
It was 790V, E1/2 = 9.5 lux seconds. Next, the photoreceptors obtained in Examples 5 and 6 were negatively charged using a commercially available copying machine, and then light was irradiated through the original image to form an electrostatic latent image, followed by dry development with positively charged toner. The image was developed using a chemical agent, and the image was electrostatically transferred to high-quality paper and fixed to obtain a clear image. A similarly clear image was obtained when a wet type developer was used as the developer. Example 7 A mixture of 1 part of β-type copper phthalocyanine and 158 parts of tetrahydrofuran was pulverized and mixed in a ball mill. The photosensitive layer forming solution obtained by adding 18 parts of 49000) and further mixing was applied onto the same aluminum-deposited polyester film as in Example 1 using a doctor blade, and dried at 100°C for 30 minutes to form a 16μ thick film. A photoreceptor of the present invention was prepared by forming a photoreceptor layer. This photoreceptor was positively charged by +6KV corona discharge using the same device as used in Example 1, and Vpo and E1/2 were similarly measured.Vpo=1200V, E1/2=3.5 It was lux second. Example 8 In the same manner as in Example 7, as a charge carrier generating pigment When using divinylbenzene compound represented by compound No. 39 as a charge transfer agent,
Vpo=1300V, E1/2=8.5 Lux・sec. Example 9 In the same manner as in Example 7, as a charge carrier generating pigment When using divinylbenzene compound represented by compound No. 40 as a charge transfer agent,
Vpo=1100V, E1/2=2.5 Lux・sec. Example 10 In the same manner as in Example 7, as a charge carrier generating pigment When using divinylbenzene compound represented by compound No. 17 as a charge transfer agent,
Vpo=1160V, E1/2=9.5 Lux・sec. Next, the photoreceptors obtained in Examples 7 to 10 were positively charged by applying a +6KV corona discharge using a commercially available electrophotographic copying machine, and then irradiated with light through the original image to form an electrostatic latent image. The image was developed using a dry developer containing negatively charged toner, and the image was electrostatically transferred and fixed onto high-quality paper to obtain a clear image. Similarly good results were obtained when a wet type developer was used as the developer. Example 11 Divinylbenzene compound represented by compound No. 5 10 parts Rhodamine B Extra 0.02 parts Polyvinyl chloride (manufactured by Nippon Carbide Co., Ltd.)
SG1100) A solution consisting of 10 parts and 70 parts of toluene was uniformly coated on a transparent paper that had been treated to prevent seepage of organic solvents and dried.
A 15μ photosensitive layer was provided. Next, the obtained photoreceptor is negatively charged by applying -6KV corona discharge using a commercially available electrophotographic copying machine, and then light is irradiated through the original image to form an electrostatic latent image, and then positively charged toner is applied to the photoreceptor. A second original copy having a clear image was obtained by developing and fixing with a dry developer.

[Brief explanation of the drawing]

1 to 3 are enlarged sectional views of a photoreceptor according to the present invention. 1... Conductive support, 2, 2', 2''... Photosensitive layer, 3... Charge carrier generating substance, 4... Charge transport layer, 5... Charge carrier generating layer.

Claims (1)

[Claims] 1. General formula on a conductive support (In the formula, R is a carbazolyl group, pyridyl group, thienyl group, indolyl group, furyl group, or a substituted or unsubstituted phenyl group, styryl group, naphthyl group, or anthryl group, and these substituents are dialkylamino groups) , an alkyl group, an alkoxy group, a carboxy group or its ester, a halogen atom, a cyano group, an aralkylamino group, an amino group, a hydroxy group, a nitro group, and an acetylamino group) 1. A photoreceptor for electrophotography, comprising a photosensitive layer containing a divinylbenzene compound as an active ingredient.