JPH03118549A - Production of organic photosensitive body for electrophotography - Google Patents

Abstract

PURPOSE:To assure the drying conditions under which the photosensitive body having excellent characteristics is obtainable and to know the conditions in a short period of time by investigating the decrease in the reactive groups possessed by a thermosetting resin contained in a resin by using an IR absorption spectrum method. CONSTITUTION:The resin layer formed by applying a coating liquid contg. a binder resin consisting of a thermoplastic resin or thermosetting resin and a solvent and drying the coating is progressed in crosslinking by a heat treatment at the time of drying, by which the cured film is formed. The completion of the heat treating conditions is known by using the IR absorption spectrum method as the means of knowing the above-mentioned conditions. Namely, the drying conditions are set by investigating the decrease of the reactive groups possessed by the thermosetting resin included in the resin layer by using the IR absorption spectrum method. The measurement of the decrease of the reactive groups is preferably executed by comparing the reactive groups with the other groups, the IR absorption of which is not influenced by the heat treatment, for example, alkyl groups, such as methyl groups.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to an electrophotographic organic photoreceptor and a manufacturing method, and more specifically, a method for manufacturing an electrophotographic organic photoreceptor in which an organic photosensitive layer is formed as an outer layer. Regarding.

(Prior Art) This type of photoreceptor generally involves coating the surface of a conductive substrate with a coating liquid prepared by mixing a binder resin, a pigment, a solvent, etc.
It is made by drying.

By the way, various layer structures have been proposed for the photosensitive layer formed by coating and drying the above coating solution. A structure has been proposed in which a layer is laminated and a surface protective layer is further provided on the outer surface of the layer.

In the photoreceptor having the laminated type photoreceptor layer described above, the surface protective layer is formed, for example, by applying a coating liquid containing a thermosetting silicone resin as a main component and curing it by heating. Here, the heat treatment process of the coating liquid is performed to sufficiently harden the thermosetting resin, and if this heat treatment is insufficient, not only will the surface hardness decrease,
Various properties such as sensitivity and repeatability of the resulting photoreceptor are deteriorated.

Therefore, the heat treatment must be carried out sufficiently, and conventionally, the heat treatment time has been determined mainly by measuring the relationship between the heat treatment time and the pencil hardness of the surface protective layer. In other words, crosslinking of the resin composition progresses through heat treatment, and there seems to be a correlation between the degree of crosslinking and the hardness of the surface protective layer. It was determined that the heat treatment was sufficient when the pencil hardness reached a predetermined value.

(Problems to be Solved by the Invention) However, even if it is determined that the pencil hardness of the surface protective layer is stable after heat treatment for a predetermined period of time, the characteristics of the obtained photoconductor may be inferior when measured. Therefore,
In order to obtain a photoconductor with excellent sensitivity characteristics, it is necessary to measure not only the pencil hardness but also the relationship between heat treatment time and sensitivity and the relationship between heat treatment time and repeatability characteristics, which is troublesome and reduces production time. It was inferior in sex.

The present invention has been made focusing on the above-mentioned actual situation,
The purpose of this is to produce electrophotographic organic photoreceptors with high productivity and stability without variations in characteristics such as sensitivity and repeatability by using a method that can reliably determine the completion of heat treatment. The purpose of the invention is to provide a method for manufacturing the same.

(Means for Solving the Problems) The method for producing an electrophotographic organic photoreceptor of the present invention includes applying a coating solution containing a binder resin made of a thermosetting resin and a solvent to the surface of a conductive substrate and drying the coating solution. A method for producing an electrophotographic organic photoreceptor provided with a resin layer formed by , the drying conditions are set, thereby achieving the above object. The thermosetting resin is preferably a silicone resin containing silicone oligomer as a main component.

The present invention will be explained in detail below.

The present invention can be applied to various methods of manufacturing laminated photoreceptors,
For example, a charge transport layer, a charge generation layer,
It can be applied to a photoreceptor formed by laminating surface protective layers in this order.

Each resin layer is formed by applying and drying a coating liquid containing a binder resin made of a thermoplastic resin or a thermosetting resin and a solvent. The present invention is applied to a resin layer in which one of a plurality of resin layers is formed by applying and drying a coating liquid containing a thermosetting resin. The coating liquid is usually dried by leaving the conductive substrate coated with the coating liquid in a drying oven. The heat treatment temperature is usually 60-130'C.

Then, crosslinking progresses in each resin layer by heat treatment during drying, and a cured film is formed. In the present invention, infrared absorption spectroscopy is used as a means of determining the completion of heat treatment conditions. That is, the drying conditions are determined by examining the reduction in reactive groups contained in the thermosetting resin contained in the resin layer using infrared absorption spectroscopy. The reduction in reactive groups is preferably measured by comparing with other groups (groups detectable by infrared absorption spectroscopy) possessed by the thermosetting resin. Other groups included in the thermosetting resin are preferably groups whose infrared absorption is not affected by heat treatment, for example, alkyl groups such as methyl groups.

To exemplify a surface protective layer formed using a silicone resin containing silicone oligomer as a main component as a thermosetting resin, the absorption peak of 3iOH (34
00cm”) and -CH3 absorption peak (2900cm
-'), measure the change in the heat treatment time over time, and determine the time when the heat treatment is completed when the ratio becomes approximately constant. That is, since silicone resin uses trifunctional alkylsilane as the main starting material, it has a silanol group (-3iQH), and this silanol group undergoes dehydration condensation during heat treatment to form -3toS.
The infrared absorption of the hydroxyl group (-OH) decreases because it becomes i-, and the infrared absorption of the methyl group (-CH3) does not change due to heat treatment. It is possible to know with certainty when the process has been completed.

In this way, the heat treatment time of the resin layer can be determined, and by setting the heat treatment time in advance, a photoreceptor having desired characteristics can be produced in a relatively short time.

In addition, although the resin layer containing a silicone resin was illustrated above, it is not limited to this, and the same method can be applied to a resin layer containing other thermosetting resins.
In this case, the same method can be carried out by determining the ratio of the absorption peak of the reactive group in the resin layer to the absorption peak of another group such as -CH3 that can be measured by infrared spectroscopy.

As other binder resins, all those conventionally used in photoreceptor coating solutions can be used, such as polyester, alkyd resin, polyamide, polyurethane, acrylic modified urethane resin, epoxy resin, polycarbonate, and polyarylate. , polysulfone, diallyl phthalate resin, ketone resin, polyvinyl butyral resin, polyether resin, phenol resin, etc. In such cases, the reactive groups include hydroxyl group, carboxyl group, amide group, incyanate group, epoxy group, etc. be. In addition, multiple types of thermosetting and curing resins may be used in combination, in which case,
The heat treatment time is long (preferably such resins are measured as described above).

Further, the present invention is applicable not only to the case of determining the heat treatment time of the charge transport layer and the charge generation layer, but also to the case of determining the heat treatment time of the charge transport layer and the charge generation layer. In addition, when determining the heat treatment time as mentioned above,
A test piece having a configuration similar to that of the photoreceptor may be prepared separately, and this test piece may be tested as described above. moreover,
By using the FT-IR RAS method, the present invention can also be used for product inspection.

(Example) Hereinafter, the present invention will be specifically explained based on Examples.

Ohka lubricant and boria arylate (manufactured by Unitika, product name U-100) 1
00 weight m, 4-(N, N-diethylamino)benzaldehyde-N, N-diphenylhydrazone 100
A charge transport layer coating solution was prepared by mixing parts by weight and 900 parts by weight of methylene chloride (CH2CI2), and this coating solution was coated on an aluminum tube with an outer diameter of 78111111 x a length of 340 mm, and then heated at 100°C for 30 minutes. A charge transport layer having a thickness of 20 μm was formed by heating and drying.

Next, on the charge transport layer, 80 parts by weight of 2,7-dibromoanthanthrone (manufactured by IC1), 20 parts by weight of metal-free phthalocyanine (manufactured by BASF), and polyvinyl acetate (manufactured by Nippon Gosei Kagaku Co., Ltd., commercially available) A charge generation layer coating solution obtained by mixing 50 parts by weight of YS-N) and 2000 parts by weight of diacetone alcohol was applied and dried under the same conditions as above to form a charge generation layer with a thickness of 0.5 μm. Formed.

Next, 7.4 parts by weight of 0.02N hydrochloric acid s and 86 parts by weight of isopropyl alcohol were mixed, and while stirring and maintaining the temperature of the mixture at 20 to 25°C, 80 parts by weight of methyltrimethquine silane was mixed. After dropping 20 parts by weight of glycidoxypropyltrimethoxysilane little by little, the mixture was left to stand at room temperature for 1 hour to obtain a silane hydrolyzate solution.

Then, this silane hydrolyzate solution was added with an average polymerization degree of 20
00 polyvinyl acetate, 20 parts by weight of acetic acid, 0.5 parts by weight of triethylamine as a hardening agent, 50 parts by weight of antimony-doped tin oxide differential powder (manufactured by Sumitomo Cement Co., Ltd.) as a conductivity imparting agent, and silicone-based Surfactant 0.
3 parts by weight was added to prepare a surface protective layer coating solution, and this surface protective layer coating solution was coated on the charge transport layer, and 12 parts by weight were added.
Cured by heating at 0°C for the predetermined time shown in Table 1 to obtain a film thickness of 2.5
A drum-shaped electrophotographic organic photoreceptor having a laminated photosensitive layer was prepared by forming a surface protective layer made of silicone resin with a thickness of μm.

Polyvinyl acetate was produced by a solution polymerization method by diluting vinyl acetate monomer with methyl alcohol and using azobisisobutyronitrile (AIBN) as a polymerization initiator. The average degree of polymerization was adjusted by appropriately controlling the amount of catalyst, amount of solvent, etc.

When heat treating the above surface protective layer, the heat treatment time and the absorption peak (3400 cm-') of 10H of the surface protective layer and -
The absorption peak of CH3 (2900cm-') was measured by infrared absorption spectroscopy, and the absorption peak of -OH (3400cn+-')/-absorption peak of -CH3 (2900cm"') was determined by calculation, and the relationship between the two was calculated. I looked into it.

The results are shown in Table 1 and FIG.

In Example 1, vinyl butyral (manufactured by Denki Kagaku Co., Ltd., Denka Butyral 5000A) was used instead of polyvinyl acetate.
) was used in the same manner as in Example 1 to form a silicone resin surface protective layer, thereby producing a drum-shaped electrophotographic organic photoreceptor having a laminated photosensitive layer.

When heat-treating the surface protective layer, as in Example 1,
Heat treatment time and absorption peak of 10H (3400am-')
The relationship with the /-CH3 absorption peak (2900 cm-') was investigated. The results are shown in Table 1 and FIG.

A silicone resin surface protective layer was formed in the same manner as in Example 1, except that in Example 1, butylated melamine resin (Mitsui Cyinamide, Kneepan 128) was used instead of polyvinyl acetate. Then, a drum-shaped electrophotographic organic photoreceptor having a laminated photosensitive layer was produced.

When heat-treating the surface protective layer, as in Example 1,
Heat treatment time and absorption peak of 10H (3400cn+-'
) / -CH3 absorption peak (2900 cm-') was investigated. The results are shown in Table 1 and FIG.

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In the same formulation as in Example 1, when the surface protective layer was heat treated, the relationship between the heat treatment time and the pencil hardness of the surface protective layer was investigated. The pencil hardness was measured using a pencil hardness tester manufactured by Sanda Kogyo ■. As a result, heat treatment time: 5 minutes: H1
Heat treatment time: 10 minutes: 3H1 Heat treatment time: 15 minutes: 4H1 Heat treatment time: 30 minutes: 5H, and their relationship is shown in FIG. From the results shown in FIG. 4, the pencil hardness reached a certain level when the heat treatment time was 30 minutes or more, so it seems that 30 minutes is sufficient for the heat treatment time.

Next, the sensitivity and repeatability of the photoreceptors obtained in Example 1 and Comparative Example 1 with different heat treatment times were measured.

The method for measuring the sensitivity and repeatability of the photoreceptor is shown below.

Sensitivity of photoreceptor: The photoreceptor was loaded into an electrostatic copying tester (manufactured by Zientic Co., Ltd., Zientic Sincere 3 (IM model)) and its surface was positively charged to give a surface potential of V +, s, p, ( Next, the charged photoreceptor was exposed to light using a halogen lamp, which is the exposure light source of the electrostatic copying tester, at an exposure intensity of 0.92 W/cm2 and an exposure time of 60 m5eC1. , find the time until the surface potential VIS, ρ becomes 1/2, and calculate the half-reduction exposure ff1l/2 (μJ/am2
) was calculated. The results are shown in Table 2 and FIG.

Repetition characteristics: After loading the above photoreceptor into a copying machine (manufactured by Mita Kogyo Co., Ltd., model DC-111) and copying 500 sheets, the surface potential after repeated exposure was determined as V2S, ρ, ( V). Further, the difference between the surface potential VIS,P, value and the surface potential V2s,p, value was calculated as a surface potential change value Δ■. The results are shown in Table 3.

Table 2 Table 3 From the above results, it was confirmed that there is a correlation between the reduction of reactive groups in the thermosetting resin by infrared absorption spectroscopy and the sensitivity and repeatability of the photoreceptor.
In Example 1, it was found from FIG. 1 that the optimum heat treatment time was 90 minutes. On the other hand, in Comparative Example 1, the pencil hardness is stable after a heat treatment time of 30 minutes as shown in FIG. However, from Tables 2 and 3, the sensitivity and repetition characteristics of the photoreceptor were optimal when the heat treatment time was 90 minutes or more, and the heat treatment time of 30 minutes, which stabilized the pencil hardness, was insufficient.

Note that (a) in FIGS. 1 to 4 shows optimal drying conditions.

(Effects of the Invention) According to the present invention, a photoreceptor with excellent properties can be obtained by examining the reduction of reactive groups in the thermosetting resin contained in the resin layer using infrared absorption spectroscopy. The drying conditions can be known reliably and in a short time, and there is no need to measure the sensitivity and repeatability of the photoreceptor as in the past, thereby increasing productivity.

4 no na! 8 Figures 1 to 3 show the heat treatment time and the 10H absorption peak (3
400cm-') / -CH30) absorption peak, (
2900cm-1), Figure 4 is a diagram showing the relationship between heat treatment time and pencil hardness, and Figure 5 is the relationship between heat treatment time and half-exposure ffi 1/2 (μJ/cm2). FIG.

that's all

Claims (2)

[Claims] 1. A method for producing an organic photoreceptor for electrophotography, in which a resin layer is formed by applying and drying a coating liquid containing a binder resin made of a thermosetting resin and a solvent on the surface of a conductive substrate. A method for producing an organic photoreceptor for electrophotography, characterized in that the drying conditions are determined by examining the reduction of reactive groups in the thermosetting resin using infrared absorption spectroscopy. 2. Claim 1, wherein the thermosetting resin is a silicone resin containing silicone oligomer as a main component.
The method for producing the electrophotographic organic photoreceptor described above.