JPS6343430B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a novel hydrazone compound, 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. 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 means that a photoconductive photoreceptor is first charged in a dark place by, for example, corona discharge, and then imagewise exposed to selectively dissipate the charge only in the exposed areas. An image is formed by obtaining an electrostatic latent image and visualizing this latent image using a developing means that uses electrostatic fine particles called toner, which is made of a colorant such as a dye or pigment and a binder such as a polymeric substance. This is one of the image forming methods. 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-generating substance) and a substance that accepts and moves the generated charge carriers (hereinafter referred to as a charge-transfer substance). Compared to photoreceptors that use the same material for charge carrier generation and charge carrier transfer, materials suitable for each function can be selected from a wide range.
It is known to provide unprecedented high sensitivity.
Requirements for 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 create the photoreceptor. It will be done. on the other hand,
The charge transfer substance has the following properties: 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. Also, what should be especially noted is that
The charge transfer material suitable for the charge generation material differs depending on the charge generation material. 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 Application Laid-Open No. 54-22834), etc. Different charge transfer materials are suitable for generation materials. As a result of research on many charge transfer materials, the present inventor found that when looking at the height of the charge potential and the difficulty of charge dissipation from the chemical structure of the charge transfer material, those with an electron donating group introduced are better. The present invention was achieved by discovering that charge dissipation is good. That is, the object of the present invention is to have an appropriate charge level in the dark when used with various charge generating substances,
In addition, as a charge transfer material whose charge quickly dissipates upon light irradiation, the general formula (wherein R represents hydrogen, a lower alkyl group, a lower alkoxy group, or a di-lower alkylamino group). These hydrazone compounds have the formula

[Formula] (R is as described above) Benzaldehydes and formulas

1-(β-hydroxyethyl)-1- represented by [Formula]
It can be produced by reacting phenylhydrazine. As this type of hydrazones, N,N-diphenyl and N-methyl-N-phenyl compounds have already been proposed (Japanese Patent Application Laid-open No. 59143/1983, etc.). The charge transfer materials described therein are effective for some types of charge generating materials, but not for all charge transfer materials. In particular, the compounds of the present invention act effectively on charge-generating substances that have a high charge level in the dark and have poor charge dissipation upon irradiation with light. These hydrazone compounds are colorless or pale yellow crystals at room temperature, and can be easily obtained by reacting the aldehyde and the hydrazone in an equimolar ratio in a suitable organic solvent, but the yield and ease of purification are limited. Considering this, it is preferable to use an excess of the hydrazine. This reaction is generally known as
It can be accelerated by adding acid.
As such acid catalysts, mineral acids such as hydrochloric acid and dilute sulfuric acid, and organic acids such as acetic acid are used. As the reaction solvent, most organic solvents can be used as long as the raw material system is well dissolved. For example, lower alcohols such as methanol and ethanol, 1, 4
- Examples include cyclic ethers such as dioxane and tetrahydrofuran, cellosolves such as methyl cellosolve and ethyl cellosolve, N,N-dimethylforformamide, and acetic acid. The reaction temperature varies depending on the reaction solvent used, but is arbitrarily selected within the range from room temperature to the boiling point. When using a solvent in which the raw material system is poorly soluble, it is preferable to raise the temperature in order to dissolve it, and when using a solvent in which the raw material system is easily soluble, the reaction proceeds at room temperature. In either case, the reaction is 1~
The reaction is completed in 5 hours, and since the compound of the present invention has good solubility in general organic solvents, a homogeneous solution is obtained when the above-mentioned organic solvents are used as reaction solvents. To extract the target product from the reaction mixture, the reaction solvent is distilled off, and the resulting resinous material is treated with dilute acetic acid to obtain it as a solid. When acetic acid is used as a reaction solvent, it can be easily obtained as a solid by diluting it with water. The pure hydrazone compound is obtained by recrystallizing the crude product thus obtained from a suitable solvent. Examples of the novel hydrazone compounds according to the present invention obtained in this manner are as follows.

【table】

【table】

[Table] The novel hydrazone compound produced in this manner is useful as a charge transfer material for electrophotographic photoreceptors as described above, and one form of its application is shown in FIG. That is, a photosensitive layer 2 is formed on a conductive support 1, on which a layer 5 containing a charge generating substance 3 is provided, and a layer 4 containing the hydrazone compound of the present invention is provided thereon. Examples are shown below. Example 1 Production example of compound (1) 2.12 gr (0.02 mol) of benzaldehyde and 1
4.57 gr (0.03 mol) of -(β-hydroxyethyl)-1-phenylhydrazine was added to 50 ml of ethanol, several drops of 1N hydrochloric acid were added thereto, and the mixture was heated under reflux for 1 hour. After cooling, ethanol was distilled off, and the resulting oil was washed with n-hexane to solidify, and recrystallized once from a methanol/water mixture and once from cyclohexane to obtain the target hydrazone compound (1). Obtained 2.13gr. Yield 44.4%, melting point 73.5~
5.0°C, Elemental analysis value Actual value Calculated value C (%) 75.30 74.97 H (%) 7.00 6.71 N (%) 11.90 11.66 The infrared absorption spectrum (KBr tablet method) of this product is shown in Figure 2. Example 2 Production example of compound (2) p-tolualdehyde 2.40g (0.02 mol), 1-
6.09 gr (0.04 mol) of (P-hydroxyethyl)-1-phenylhydrazine was added to 50 ml of ethanol, several drops of 1N hydrochloric acid were added thereto, and the mixture was heated under reflux for 1 hour. After cooling, ethanol was distilled off, and 50 ml of 10% acetic acid aqueous solution was added to the obtained oily substance, solidified by stirring, and mixed with toluene-cyclohexane (3:7
Volume ratio) The mixture was recrystallized twice to obtain 2.0 gr of the target hydrazone compound (2). Yield 39.4%,
Melting point 88.5-9.5℃. Elemental analysis value Actual value Calculated value C (%) 75.80 75.56 H (%) 7.24 7.13 N (%) 10.89 11.09 The infrared absorption spectrum (KBr tablet method) of this product is shown in Figure 3. Example 3 Production example of compound (5) p-anisaldehyde 2.72g (0.02mol), 1
6.09 gr (0.04 mol) of -(β-hydroxyethyl)-1-phenylhydrazine was added to 50 ml of ethanol, several drops of 1N hydrochloric acid were added thereto, and the mixture was heated under reflux for 1 hour. After cooling, ethanol was distilled off, and 50 ml of a 10% aqueous acetic acid solution was added to the resulting oil, solidified by stirring, and recrystallized twice from a toluene-cyclohexane (3:7 volume ratio) mixture to obtain the desired product. 4.43 gr of a certain hydrazone compound (5) was obtained. Yield 81.9%, melting point 93.5-4.5℃. Elemental analysis value Actual value Calculated value C (%) 71.04 71.09 H (%) 6.68 6.71 N (%) 10.31 10.36 The infrared absorption spectrum (KBr tablet method) of this product is shown in FIG. Example 4 Production example of compound 10 4-(N,N-dimethylamine)benzaldehyde 2.98gr (0.02mol), 1-(β-hydroxyethyl)-1-phenylhydrazine 6.09gr
(0.04 mol) was added to 50 ml of acetic acid, and the mixture was heated and stirred at 85 to 90°C for 1 hour. After cooling, acetic acid was distilled off, and 100 ml of a 5% aqueous acetic acid solution was added to the obtained oil to solidify it, which was recrystallized twice from an aqueous ethanol solution to obtain 4.27 gr of the target hydrazone compound (10). Yield 75.3%, melting point 123.0-5.0℃. Elemental analysis value Actual value Calculated value C (%) 71.76 72.05 H (%) 7.54 7.47 N (%) 14.59 14.83 The infrared absorption spectrum (KBr tablet method) of this product is shown in FIG. Example 5 Production example of compound 11 17.7 gr (0.1 mol) of 4-(N,N-diethylamino)benzaldehyde, 30.4 gr (0.2 mol) of 1-(β-hydroxyethyl)-1-phenylhydrazine
mol) was added to 100 ml of acetic acid, and the mixture was heated and stirred at 70 to 75°C for 1 hour. After cooling, 900 ml of water was added and stirred, and the obtained crystals were mixed with toluene-cyclohexane (1:9
Volume ratio) was recrystallized to obtain 19.0 gr of the target hydrazone compound (11). Yield 61.0%, melting point 83.5
~4.5℃. Elemental analysis value Actual value Calculated value C (%) 73.47 73.28 H (%) 8.25 8.09 N (%) 13.22 13.49 The infrared absorption spectrum (KBr tablet method) of this product is shown in FIG. Application example 4′,4″-bis[2-hydroxy-3-(2,4
-dimethylphenylcarbamoyl)-1-naphthylazo]-1,4-distyrylbenzene (3 parts by weight), 1 part by weight of polyester resin (Polyester Ad-T-Sibu 49000, manufactured by Dupont), and 96 parts by weight of tetrahydrofuran were ground in a ball mill. The dispersion obtained by mixing was applied using a doctor blade onto a polyester film coated with aluminum, and dried for 5 minutes in an oven at 80°C to a thickness of approximately
A charge carrier generation layer of 0.1 μm was formed. Next, the hydrazone compound produced in Example 5 (compound
No. 11) A solution consisting of 1 part by weight, 1 part by weight of polycarbonate resin, and 8 parts by weight of tetrahydrofuran was applied onto the charge carrier generation layer using a doctor blade, dried at 100°C for 10 minutes, and formed into a layer with a thickness of about 20μ. A charge transfer layer was formed. This photoreceptor was negatively charged by applying -6KV corona discharge for 20 seconds using a commercially available electrostatic copying paper testing device.
Leave it in the dark for a second, and the surface potential at that time Vpo (V)
Then, the surface is irradiated with light using a tungsten lamp at an illuminance of 20 lux, the time (seconds) until the surface potential becomes 1/2 of Vpo is determined, and the half-reduction exposure amount E1/ 2 (lux seconds)
I got it. The result is Vpo = 1263 volts, E1/2 =
It was 2.4 lux seconds.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view of an example of an electrophotographic photoreceptor using the hydrazone compound of the present invention, and FIGS. 2 to 6 show infrared absorption spectra of the hydrazone compounds produced in Examples 1 to 5, respectively. DESCRIPTION OF SYMBOLS 1... Conductive support, 2... Photosensitive layer, 3... Charge generating substance, 4... Layer containing a charge generating substance, 5... Layer containing a hydrazone compound.

Claims (1)

[Claims] 1. General formula (However, R represents hydrogen, a lower alkyl group, a lower alkoxy group, or a di-lower alkylamino group.) A hydrazone compound represented by the following.