JPH0467152A - Method for inspecting coating liquid of photosensitive body - Google Patents

Abstract

PURPOSE:To easily identify whether coating liquid is defective or nondefective and to improve production efficiency by evaluating the sensitivity of an electrophotographic org. photosensitive body by the ratio of the absorbance of the two peaks formed in the absorption spectra of a specific sample. CONSTITUTION:The absorption spectra of the sample formed of the coating liquid contg. a charge generating material, binder resin and solvent are measured and the sensitivity of the electrophotographic org. photosensitive body is evaluated by the ratio of the absorption spectra of the two peaks formed in the absorption spectra. Namely, a correlative relation holds between the ratio of the absorbance of the peaks of the absorption spectra obtd. from the coating liquid and the sensitivity of the photosensitive body. Then, if the range where the coating liquid is usable is previously determined from the ratio of the absorbance of the two peaks of the absorption spectra, the subsequent need for evaluating the coating liquid by forming the photosensitive body each time is eliminated. Since the coating liquid is inspected in a short period of time in this way, the continuous production is possible. In addition, the quality is stabilized. and the production efficiency is improved.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a method for inspecting a photoconductor coating liquid used to form a photosensitive layer of an electrophotographic organic photoconductor, and more specifically, to a method for inspecting a photoconductor coating liquid used to form a photosensitive layer of an electrophotographic organic photoconductor. This invention relates to an inspection method that allows easy discrimination.

(Prior Art and Problems to be Solved by the Invention) A photoconductor coating liquid is prepared by dissolving a binder resin in a solvent and mixing a charge generating material, a charge transporting material, etc. A photoreceptor is manufactured by applying a liquid in a laminated or single layer and drying to form a photosensitive layer. The photoreceptor is
It is required to have a high @ temperature, to have excellent performance stability during repeated use, and to have excellent quality stabilization in mass production.

However, when a photoreceptor is produced using a coating solution that has been stored for a long period of time, the characteristics of the photoreceptor tend to deteriorate.

The reason for this is that when the coating solution is left for a long period of time, the crystal type of the charge-generating material in the coating solution changes, crystal growth, and particle aggregation are promoted, resulting in a change in the crystalline state compared to the initial stage of production. It is thought that the photoreceptor characteristics deteriorate due to a reduction in the charge generation efficiency or injection efficiency of the charge generation material in the photoreceptor layer prepared using the coating liquid.

Therefore, when creating a photoreceptor using a coating solution that has been used for a long time, conventionally, a photoreceptor is prepared experimentally using the coating solution, and the characteristics of the photoreceptor are measured. It was used to determine whether the product was good or bad. Only after the photoreceptor is created in this way can it be determined whether the coating liquid can be used or not, and because it takes a long time to determine whether the coating liquid to be used is good or bad, production has to be stopped during that time. wozu,
In addition to poor production efficiency, a certain amount of time is required before the characteristics of the photoreceptor can be measured, so that by the time the test results are known, the coating liquid may already be unusable.

On the other hand, attempts have been made to determine the quality of the coating liquid by measuring the particle size of the pigment in the coating liquid and determining its agglomeration state, but in this case, the characteristics of the photoreceptor and its There is no correlation with the agglomeration state (and it was not possible to evaluate the characteristics of the photoreceptor from the coating solution.

The present invention has been made in view of the above-mentioned circumstances, and its purpose is to enable continuous production and increase production efficiency by easily determining the quality of the coating liquid. An object of the present invention is to provide a method for testing a liquid applied to the body.

(Means for Solving the Problems) The present invention is a method for inspecting a photoreceptor coating liquid used for forming a photosensitive layer of an electrophotographic organic photoreceptor, which includes a charge generating material, a binder resin, and a solvent. The absorption spectrum of a sample formed with a coating solution containing is achieved. When a perylene pigment is used as the charge generating material, it is particularly preferable for the inspection method of the present invention.

(Function) As a result of intensive research, the present inventors found that a correlation exists between the ratio of the absorbance of the peak of the absorption spectrum obtained from the coating liquid and the sensitivity of the photoreceptor. Therefore,
In the present invention, whether or not the coating liquid to be used can be used to manufacture a photoreceptor with desired characteristics can be determined by preparing a sample such as a film using the coating liquid and determining the absorption of the film. The spectrum is measured and discrimination is made based on the ratio of the absorbance of two peaks formed in the absorption spectrum. Here, the absorption spectrum is usually 400 nm.
means a light absorption spectrum in the range ˜800 nI.

This will be explained with reference to FIG. FIG. 1 shows the absorption spectrum of a film formed using a coating solution for a single-layer photosensitive layer in which a binder resin, a pigment, and a charge transporting material are dispersed in a solvent.

The solid line (a) in Figure 1 represents the absorption spectrum using the coating liquid immediately after it was manufactured, and the - dotted line (b) represents the absorption spectrum of the coating liquid after the manufactured coating liquid was rotated and stirred for two days in a roll mill. The broken line <C> represents the absorption spectrum of the coating solution after the produced coating solution was rotated and stirred for 4 days in a roll mill.

Each absorption spectrum has two or more peaks, and for example, compared to the absorbance at 480 nm, the absorbance at 50 ha gradually increases from (a)-(t+)-(C), so the storage of the coating solution It can be seen that the crystal shape changes over time. 5 for absorbance at 4B0nm
When examining the ratio of absorbance at 50 nm, the absorption spectrum (a
) is 75.4%, and absorption spectrum (b) is 90.3%.
%, and the absorption spectrum <c> is 96.5%. In addition, when the sensitivity of the photoreceptor prepared using each coating liquid was measured, the sensitivity of the coating liquid (a) immediately after manufacture was 20 GV,
254 V for the coating solution (b) after stirring for 2 days in a roll mill, and 254 V for the coating solution (C) after stirring for 4 days in a roll mill.
) was 285v.

(However, the measurement of the sensitivity of the photoreceptor is as follows.The coating solution was applied onto an aluminum tube with an outer diameter of 1BlIlrrrs and a length of 340mm, and then heat-dried at 100°C for 130 minutes to obtain a film thickness of 24μ. A single photosensitive layer is formed to produce an electrophotographic photoreceptor.The photoreceptor obtained above is mounted on DC-1656 manufactured by Sanda Kogyo, the surface potential is set to 750V, the exposure scale is set to 40, and the Munsell original N8.0 is used as the original. Sensitivity is evaluated by the potential when the N8.0 original is placed in this copying machine.In order to obtain a good image when installed in this copying machine, the potential of the N8.0 original is 200 to 280■. From the results, it is clear that there is a correlation between the absorbance ratio of the two peaks formed in the absorption spectrum of the coating solution and the sensitivity of the photoreceptor.For example, in the above example, the absorbance of the two peaks of the absorption spectrum The ratio is 75.4% or more and 96.4% or less, preferably 96.0
% or less, more preferably 95.0% or less, it can be seen that a highly sensitive photoreceptor can be produced using the coating liquid.

Therefore, if the range in which the coating solution exhibits usable sensitivity is determined in advance from the ratio of the absorbance of the two peaks in the absorption spectrum, there is no need to create each photoreceptor and evaluate the coating solution. .

This absorption spectrum measurement can be easily and quickly carried out by preparing a film using a coating liquid and performing the measurement on the film, or directly on the coating liquid.

Therefore, if the ratio of the absorbance of the peak of the absorption spectrum obtained from the coating liquid is set within a predetermined range according to the required characteristics of the photoreceptor, a photoreceptor with good sensitivity can be produced.

Note that in the above explanation, the ratio of the absorbance at 55'Onm to the absorbance at 480rv in the absorption spectrum was explained.
The ratio of the absorbance at 480 nm to the absorbance at 550 nm may also be examined, and in this case also a correlation with the sensitivity of the photoreceptor can be seen. Furthermore, the ratio between another peak in the absorption spectrum and the above-mentioned peak value (4B0n■ or 550 nm) may be measured. Alternatively, the absorption spectrum of the coating liquid may be directly measured.

(Preferred Embodiment) The photoconductor coating liquid used in the present invention is prepared by mixing a binder resin, a charge generating material, a solvent, etc., and this coating liquid is applied onto a conductive substrate, dried, and exposed to light. An electrophotographic photoreceptor is created by forming layers.

The above-mentioned photosensitive layer includes a single layer type in which a charge generation material, a charge transport material and a binder resin are mixed, and a multilayer type in which a charge generation layer and a charge transport layer are laminated. It is applicable to both.

As the charge generating material, any conventionally used charge generating material can be used, and for example, the following formula (1
), (wherein R represents an alkyl group or an allyl group) selenium, selenium-tellurium, amorphous silicon, pyrylium salt, anthanthrone pigment, phthalocyanine pigment, indigo pigment, triphenylmethane pigments, threne pigments, toluidine pigments,
Examples include pyrazoline pigments, azo pigments, and quinacridone pigments.

As the charge transport material, conventionally used charge transport materials can be used, such as oxadiazoles such as 2,5-di(4-methylaminophenyl)-1,3,4-oxadiazole. styryl compounds such as 9-(4-diethylaminostyryl)anthracene,
Carbazole compounds such as polyvinyl carbazole, l
-Pyrazoline compounds such as phenyl-3-(P-dimethylami/phenyl)pyrazole, hydrazone compounds,
Nitrogen-containing cyclic compounds such as triphenylamine compounds, indole compounds, oxazole compounds, inoxazole compounds, thiazole compounds, thiadiazole compounds, imidazole compounds, pyrazole compounds, triazole compounds, etc., fused polycyclic compounds Compound force is exemplified. These charge transport materials may be used alone or in combination of two or more.

As the binder resin, any conventionally used binder resin can be used, such as styrene polymer,
Styrene-butadiene copolymer, styrene-acrylonitrile copolymer, styrene-maleic acid copolymer, acrylic polymer, styrene/7-acrylic copolymer, ethylene-vinyl acetate copolymer, polyvinyl chloride, chloride Vinyl-vinyl acetate copolymer, polyester, alkyd resin, polyamide, polyurethane, acrylic modified urethane resin, epoxy resin, polycarbonate, polyarylate, polysulfone, diallyl phthalate resin, silicone resin, ketone resin, polyvinyl butyral resin, polyether resin, Various polymers such as phenol resins are exemplified. Furthermore, photocurable resins such as epoxy acrylate can also be used. Furthermore, photoconductive polymers, e.g.
Poly-N-vinylcarbazole or the like may also be used as a binder resin.

The above-mentioned solvent can be appropriately selected from conventionally known solvents depending on the type of the above-mentioned binder resin etc., for example,
Alcohols such as methanol, ethanol, propatool, impropatool, butanol, aliphatic hydrocarbons such as n-hexane, octane, cyclohexane, aromatic hydrocarbons such as benzene, toluene, xylene, dichloromethane, Halogenated hydrocarbons such as dichloroethane, carbon tetrachloride, and chlorobenzene, ethers such as dimethyl ether, diethyl ether, tetrahydrofuran, ethylene glycol dimethyl ether, and ethylene glyfur diethyl ether, ketones such as acetone, methyl ethyl ketone, and cyclohexanone, ethyl acetate, and methyl acetate. Various solvents such as esters are exemplified, and these solvents may be used alone or in combination of two or more.

Examples of the conductive substrate include simple metals such as aluminum, copper, tin, platinum, silver, vanadium, molybdenum, chromium, cadmium, titanium, nickel, palladium, indium, stainless steel, and brass, and metals such as vapor-deposited or laminated metals. Examples include glass coated with aluminum iodide, tin oxide, indium oxide, etc.

The conductive substrate may be in the form of a sheet or a drum, and it is sufficient that either the substrate itself has conductivity or the surface of the substrate has conductivity.

The substrate preferably has sufficient mechanical strength during use.

In the laminated electrophotographic photoreceptor, the charge generation material and the binder resin constituting the charge generation layer can be used in various ratios, but with respect to 100 parts (parts by weight, same hereinafter) of the binder resin, 5 to 500 parts of charge generating material, especially 10 to 25 parts
Preferably, it is used in a proportion of 0 parts.

Further, the charge generation layer may have an appropriate thickness, but may have a thickness of 0.0000. It is preferable that the thickness is 01 to 5 μm, particularly about 0.1 to 3 μm.

The charge transport material and the binder resin constituting the charge transport layer can be used in various ratios, but in order to easily transport the charges generated in the charge transport layer by light irradiation,
For 100 parts of binder resin, charge transport material lO~SOO
Parts, particularly preferably 25 to 200 parts.

In addition, the charge transport layer contains 2 to 100 μl, especially 5 to 30 μl.
Preferably, the thickness is formed to a degree of .mu.m.

In a single-layer type electrophotographic photoreceptor, the charge generating material is 2 to 20 parts, especially 3 to 15 parts, and the charge transporting material is 40 to 200 parts, especially 50 to 100 parts, based on 100 parts of the binder resin.
It is appropriate that the Further, the thickness of the single-layer type photosensitive layer is preferably about 10 to 508 m, particularly about 15 to 258 m.

When a photosensitive layer including a charge generation layer and a charge transport layer is formed by a coating method, the charge generation material or the charge transport material and the binder resin are coated using a conventionally known method such as a roll mill, a ball mill, an attritor, or a paint shaker. , prepare a coating solution using an ultrasonic disperser or the like.

(Experiment example) Hereinafter, the present invention will be explained in more detail based on experimental examples.

Polycarbonate as a binder resin (Mitsubishi Gas Chemical Co., Ltd.,
Product name: Lido book'$-)Z) 100N! ! parts by weight, N as a charge-generating material, N-di(3,5-dimethylphenyl)perylene-3,4,9,10-tetracarboxydiimide 8]tr parts by weight, N as a charge-transporting material, N,
1 part by weight of N'', N-tetrakis(3-tolyl)-1,3-phnylenediamine, 1 part by weight of polydimethylsiloxane O, O as a plasticizer, and a predetermined amount of tetrahydrofuran were mixed using an ultrasonic dispersion machine. A coating solution for a single-layer type photosensitive layer was prepared by mixing with stirring.

Next, after storing this coating solution under the conditions shown below, each coating solution was coated onto an aluminum tube with an outer diameter of 711a+m and a length of 340++n, and then heat-dried at 100'C for 130 minutes to form a film with a film thickness of 24μ. An electrophotographic photoreceptor was prepared by forming the same single-layer photoreceptor layer. Further, each coating solution was applied onto a transparent polyethylene sheet using Barco 9-NO40 and dried to form a film having a thickness of 1 (lμ).

The storage conditions are as follows (however, room temperature,
(Carried out at normal pressure).

Experimental example ■: Coating liquid immediately after preparation Experimental example ■: A 50 umami λ coating liquid is sealed in a 200 mλ glass bottle and stored on a 50r+80 ball mill platform with stirring at two rotations.

Experimental Example (2): 50 ml of the coating solution was sealed in a 200 mff1 glass bottle and stored with rotational stirring on a ball mill platform at 50 rpm for 4 days.

Experimental example ■: Store in a dark place for 10 days.

Experimental example ■: Store in a dark place for 25 days.

Experimental Example (2): 5 h+fL of the coating solution is sealed in a 200 ml glass bottle and stored with rotational stirring on a ball mill platform at 50 rpm for 20 days.

<Evaluation of photoreceptor> The photoreceptor obtained above was mounted on a Sanda Kogyo model DC-1655, the surface potential was set to 7 S OV, the exposure scale was set to O, and the potential was determined when a Munsell original N8.0 was placed on the original. was used as the evaluation of sensitivity. The results are shown in Table 1. In order to obtain good images with this copying machine, the potential of the N8.0 original must be 20
This is when it is 0 to 280■.

<Evaluation of the absorption spectrum of the film) The absorption spectrum of the film on the transparent polyethylene sheet obtained above was measured using a new U-3210 self-recording spectrophotometer manufactured by Hitachi, and the ratio of the absorbance of the peaks at 550 nm and 480 nm was calculated. It was measured. The results are also shown in Table 1.

Table 1: Absorbance of the peak at 550 nm As shown in Table 1, there is a correlation between the sensitivity of the photoreceptor and the absorbance ratio of the two peaks of the coating solution, and in the case of the coating solution of the above example, the peak The ratio is 75.4% to 964%
It shows good sensitivity when it is within the range of . Therefore, if a coating liquid within the above range is used, a photoreceptor exhibiting good electrophotographic properties can be obtained.

(Effects of the Invention) According to the present invention, it is possible to determine whether the coating liquid is good or bad by simply examining the absorption spectrum of the sample formed with the coating liquid. There is no need to measure sensitivity.

Therefore, since the coating liquid can be inspected in a short time, continuous production is possible, and electrophotographic organic photoreceptors with stable quality can be manufactured.

4. Figure 1 shows the absorption spectrum of a film formed using a photoreceptor coating solution.

Figure 1 (nm)

Claims (1)

[Claims] 1. A method for inspecting a photoreceptor coating liquid used for forming a photosensitive layer of an electrophotographic organic photoreceptor, the coating liquid containing a charge generating material, a binder resin, and a solvent. A method for inspecting a photoreceptor coating solution, which comprises measuring the absorption spectrum of a sample formed in the process and evaluating the sensitivity of the electrophotographic organic photoreceptor based on the ratio of the absorbances of two peaks formed in the absorption spectrum. 2. The method for inspecting a photoreceptor coating liquid according to claim 1, wherein the charge generating material is a perylene pigment.