JPH0430424B2 - - Google Patents

Description

[Detailed description of the invention]

Technical Field The present invention relates to a novel hydrazone compound and a method for producing the same, and more particularly, to a hydrazone compound that effectively functions as a charge transfer material in an electrophotographic photoreceptor containing a charge generation material and a charge transfer material, and a method for producing the same. . Prior Art Conventionally, inorganic materials such as selenium, cadmium sulfide, and zinc oxide have been used as photoconductive materials for photoreceptors used in electrophotography. The "electrophotographic method" referred to here generally refers to a method in which a photoconductive photoreceptor is first charged in a dark place by, for example, corona discharge, and then exposed imagewise to selectively dissipate the charge only in the exposed areas. Obtain an electrostatic latent image,
One of the image forming methods in which an image is formed by visualizing this latent image area using a developing means using electrostatic fine particles called toner, which is made of a coloring material such as a dye or pigment and a binder such as a polymeric substance. It is one. In such electrophotography, the basic characteristics required of the photoreceptor are (1) the ability to be charged to an appropriate potential in the dark, (2) less dissipation of charge in the dark, and (3) the ability to charge to an appropriate potential in the dark. ) The charge can be quickly dissipated by light irradiation. The conventionally used inorganic photoreceptors have many advantages but also have various drawbacks, so in recent years, electrophotographic photoreceptors using many organic materials have been proposed and put into practical use. There are things that are. Among them, a photoreceptor is composed of a substance that absorbs light and generates charge carriers (hereinafter referred to as a charge generation substance) and a substance that accepts the generated charge carriers and moves them (hereinafter referred to as a charge transfer substance). Compared to photoreceptors that use the same material for charge carrier generation and charge carrier transfer, a wide range of materials suitable for each function can be selected.
It is known to provide unprecedented high sensitivity.
Requirements for the materials used in this type of photoreceptor include that the charge-generating substance absorbs the desired light and generates charge carriers, that the charge carrier generation efficiency is high, and that it is easy to process to produce the photoreceptor. Can be mentioned. On the other hand, the charge transfer substance has the following characteristics: it easily accepts charge carriers from the charge generation substance, the charge carriers move quickly, and it does not absorb in the photosensitive region of the charge generation substance. What should be noted in particular is that suitable charge transfer substances differ depending on the charge generation substance. If the combination of the charge-generating material and the charge-transfer material is not appropriate, a sufficient charge potential may not be obtained in the dark, or the charge may not dissipate sufficiently during light irradiation, resulting in low density and low-density images. or the scalp becomes dirty. In general, objects with a high charge potential in the dark tend to have poor charge dissipation, and objects with good charge dissipation tend to have a low charge potential.This is due to charge generation substances and charge transfer. Depends on the substance. Practically speaking, an appropriate combination is selected that provides sufficient charge dissipation to the extent that the background is not smudged and provides a sufficient charge level to provide sufficient image density. A large number of charge-generating substances have been proposed, and one particularly effective one is, for example, CI Pigment Blue 25 (Color Index).
21180), an azo pigment with a carbazole bone core (Japanese Patent Application Laid-open No. 53-95033), an azo pigment with a triphenylamine bone core (Japanese Patent Publication No. 53-132347), an azo pigment with a styrylstilbene bone core (Japanese Patent Publication No. 53-1999) −
133445) Azo pigments with diphenyloxadiazole bone cores (Japanese Patent Application Laid-Open No. 12742/1982) and azo pigments with fluorenone bone cores (Japanese Patent Laid-Open No. 54-22834), etc. Different charge transfer materials are suitable for generation materials. Purpose The purpose of the present invention is to provide a compound that effectively functions as a charge transfer substance in an electrophotographic photoreceptor, that is, when used together with various charge generation substances, has an appropriate charging potential in a dark place, and when irradiated with light, It is an object of the present invention to provide a hydrazone compound whose charge quickly dissipates and a method for producing the same. Structure The present invention is based on the general formula () (In the formula, Ar represents a phenyl group, R represents a lower alkyl group or a benzyl group.) Regarding the hydrazone derivative represented by the general formula () (In the formula, Ar and R are the same as the general formula ().) A hydrazine derivative represented by the formula () General formula () characterized by reacting with an aldehyde compound represented by (In the formula, Ar and R are the same as above.) The present invention relates to a method for producing a hydrazone derivative represented by the following formula. The hydrazone compound of the present invention is a colorless or pale yellow crystal at room temperature, and has the general formula ()
It can be easily obtained by reacting a hydrazine derivative of formula (2) with an aldehyde compound of formula (2) in an equimolar ratio in a suitable organic solvent. This dehydration condensation reaction can be accelerated by adding an acid, as is generally known, and for example, inorganic acids such as hydrochloric acid and dilute sulfuric acid and organic acids such as acetic acid are used. As the organic solvent used as the reaction solvent, almost any organic solvent can be used as long as it dissolves the reaction system, including lower alcohols such as methanol and ethanol, and cyclic ethers such as 1,4-dioxane and tetrahydrofuran. ,
Examples include cellosolves such as methyl cellosolve and ethyl cellosolve, N,N-dimethylformamide, and acetic acid. The reaction temperature varies depending on the reaction solvent; when using N,N-dimethylformamide, etc., which has good solubility in the reaction system, the reaction proceeds at room temperature, and when using ethanol, etc., whose reaction system is poorly soluble at room temperature, the reaction proceeds. is preferably heated to reflux. In either case, the reaction is completed in 1 to 5 hours. Specific examples (Nos. 1 and 2) of the hydrazone compound represented by the general formula () thus obtained are as shown below. Effects The hydrazone compound of the present invention functions effectively as a charge transfer substance in an electrophotographic photoreceptor, and when used together with various charge generation substances,
It has an appropriate charging potential in a dark place, and the charge quickly dissipates when irradiated with light. Hereinafter, the effects of the present invention will be specifically illustrated by Examples (manufacturing examples of hydrazone compounds according to the present invention) and Application Examples (applications to electrophotographic photoreceptors). Example 4 - Dissolve 32.4 g (0.1 mol) of N,N-diphenylaminonaphthaldehyde in 100 ml of N,N-dimethylformamide, and add 5 ml of 1N hydrochloric acid to this.
While stirring, 14.7 g (0.12 mol) of 1-methyl-1-phenylhydrazine was added dropwise over 30 minutes. After further stirring at room temperature for 1 hour, 200 ml of water was added, and the precipitate precipitated was collected, dried, and recrystallized from ethyl acetate-ethanol to obtain the desired product (Compound No. 1). In addition, a hydrazone compound of Compound No. 2 was obtained by using 1-benzyl-1-phenylhydrazine in place of the above-mentioned 1-methyl-1-phenylhydrazine. The yield, melting point, and elemental analysis values of each hydrazone compound are shown in the table below. Infrared absorption spectrum of No. 1 hydrazone compound (KBr tablet method)
is shown in the figure.

[Table] Application example 76 parts of Diane Blue (CI Pigment Blue 25, CI21180) as a charge generating substance, 2% of polyester resin (Vylon 200, manufactured by Toyobo Co., Ltd.)
1,260 parts of tetrahydrofuran solution and 3,700 parts of tetrahydrofuran were pulverized and mixed in a ball mill, and the resulting dispersion was applied onto the aluminum surface of a conductive support using a doctor blade and air-dried to generate a charge with a thickness of approximately 1 μm. formed a layer. On the other hand, as a charge transfer substance, 2 parts of the hydrazone compound of Synthesis Example 1, 2 parts of polycarbonate resin (Panlite K1300, manufactured by Teijin Ltd.), and 16 parts of tetrahydrofuran were mixed and dissolved to form a solution, and this was added to the charge generation layer. A charge transport layer having a thickness of about 20 μm was formed by coating the photoreceptor on top using a doctor blade and drying at 80° C. for 2 minutes and then at 105° C. for 5 minutes to prepare photoreceptor No. 1. In addition, photoreceptor No. 2 was prepared by replacing the hydrazone compound and charge generating substance of Synthesis Example 2 as charge transfer substances. For comparison, as a charge transfer substance, the formula ()
Photoreceptor No. 3 was prepared using a hydrazone compound in which R represents a phenyl group and using the same charge generating material as photoreceptor No. 1.

【table】

[Table] Regarding the photoreceptors No. 1 to 3 made in this way,
Commercially available electrostatic copying paper testing device (manufactured by KK Kawaguchi Denki)
SP428 type) to perform corona discharge of -6KV or +6KV for 20 seconds to charge it, leave it in a dark place for 20 seconds, measure the surface potential Vpo (volt) at that time, and then expose it to tungsten lamp light. The body surface was irradiated with illuminance of 4.5 lux, and the time (seconds) until the surface potential became 1/2 of Vpo was determined, and the exposure amount E1/2 (lux/second) was calculated.
In addition, the surface potential V30 when left for 30 seconds after light irradiation
(volt), that is, the residual potential was measured. The results are shown in Table-3.

[Table] Photoreceptors 1 to 3 have a high initial potential Vpo and a high sensitivity E.
It was also 1/2 as expensive. Regarding the characteristic of residual potential V30, photoreceptors 1 and 2 using the compound of the present invention were sufficiently low, whereas comparative photoreceptor 3 was high and inferior. Next, each of the above three types of photoreceptors is charged using a commercially available electrophotographic copying machine, and then light is irradiated through the original image to form an electrostatic latent image, which is then transferred to a wet developer. The resulting toner image was electrostatically transferred onto plain paper to obtain a copy image.
When photoreceptors 1 and 2 were used, clear images with high image density and no background stains were obtained; however,
When photoreceptor 3 was used, the copied image had noticeable background stains.

[Brief explanation of drawings]

The figure shows the infrared absorption spectrum (KBr tablet method) of No. 1 hydrazone compound.

Claims (1)

[Claims] 1 General formula () (In the formula, Ar is a phenyl group, R is a lower alkyl group,
Or represents a benzyl group. ) A hydrazone derivative represented by 2 General formula () (In the formula, Ar is a phenyl group, R is a lower alkyl group,
Or represents a benzyl group. ) and the hydrazine derivatives shown by the formula () General formula () characterized by reacting with an aldehyde compound represented by (In the formula, Ar and R are the same as in the general formula ()) A method for producing a hydrazone derivative represented by the following formula.