JP2006162670A5 - - Google Patents

Description

Method for producing electrophotographic photosensitive member

The present invention relates to the production how the electrophotographic photosensitive member, in particular, to improve the film thickness of the sauce is inevitable coating ends in a dip coating method, has a uniform thickness over the coated area the entire image The present invention relates to a method for producing an electrophotographic photoreceptor excellent in uniformity.

  The electrophotographic photosensitive member takes a repeated process of charging, exposure, development, transfer, cleaning and static elimination in the image forming process. In addition, due to the recent trend of miniaturization of electrophotographic apparatuses, the size of electrophotographic photoreceptors is also required to be smaller.

  Under such circumstances, in order to achieve image uniformity, the electrophotographic photosensitive member is uniform over the entire photosensitive layer formed by coating, and also maintains film thickness uniformity at the end of the coating region. Is required.

  In particular, in a general dip coating method as a method for producing an electrophotographic photosensitive member, the film thickness variation at the upper end of coating (a phenomenon in which the film thickness gradually increases from the upper end immediately after the start of coating to the lower side. Various methods have been employed to reduce the thickness of the film as much as possible.

  Specifically, a general method is to control the coating speed immediately after the start of coating to allow extra coating liquid to adhere in advance, or to add a low boiling point component to the solvent of the coating liquid to increase the drying speed. It is. Furthermore, a method for heating the substrate to be coated to increase the drying speed (for example, see Patent Document 1), a method for heating the atmosphere of the substrate to be coated to increase the drying speed (for example, see Patent Document 2), and Discloses a method of heating at least one of the surface of the substrate and the coating solution (for example, see Patent Document 3).

  However, the control of the coating speed for adhering extra coating liquid in advance as described above, that is, the control method of increasing the initial speed with respect to the central coating speed, or the method of adding a low boiling point solvent alone, Although effective against film thickness sagging, the effect is limited.

  In this regard, as a method for realizing a further effect, the method of heating and applying at least one of the surface of the substrate and the coating solution mentioned above is the basic volatilization rate of the dilution solvent contained in the coating solution. The coating can be carried out very effectively by raising the. However, in recent years, the higher image quality required for electrophotographic photosensitive members has led to a greater demand for coating uniformity, and at the same time, a laminated electrophotographic photosensitive member for the purpose of improving printing durability and the like. However, in order to improve the strength of the charge transport layer, in addition to increasing the molecular weight of the constituent resin, further thickening is required. And when forming such a thick film by the dip coating method, the degree of film thickness tends to be worse than that of a thin film.

  Here, referring to the factors constituting the film thickness uniformity which is an important quality factor in the coating film, the viscosity of the coating solution has a great influence on the film thickness uniformity. Ideally, the viscosity of the resin does not change at all timings during application lifting.

  On the other hand, among the methods of heating and applying at least one of the surface of the substrate and the coating solution, if the temperature of the substrate during dipping and pulling is higher than that of the coating solution, if the coating rising speed is constant, the formation The thickness of the applied coating causes a phenomenon that it continuously decreases after a peak due to sagging that occurs at least after the start of coating.

There degree this thickness reduction progresses, that the strength of the film thickness change of the coating, the length of time that the heat exchange is made between the substrate and the coating solution, the temperature difference between the substrate and the coating liquid, the coating liquid Although it changes depending on a plurality of factors such as viscosity, the change becomes strongest when the temperature difference between the substrate and the coating solution is large. Therefore, in order to obtain the maximum effect of the coating method for heating the substrate and the coating solution, and at the same time, to suppress the change in the film thickness due to continuous heat exchange, the temperature of both the substrate and the coating solution is set higher. One method is considered to be the same, but in the management of the coating liquid, there are concerns about problems such as bubble generation due to temperature unevenness in the liquid feeding system and durability of the coating liquid constituent material in a high temperature environment. The temperature of the liquid cannot be kept so high compared to the substrate.

Moreover, regarding the binder resin used as one of the methods for improving the strength of the coating film, as a solvent for dissolving the binder resin, a solvent having excellent compatibility with the binder resin and having a relatively low boiling point is used. Is ideal in minimizing sagging of the coating. However, if a low-boiling solvent cannot be expected in a solvent group with good compatibility with the binder resin in the selection of the solvent, that is, if it is unavoidable to use only a high-boiling solvent, the coating due to a delay in volatilization is required. in order to suppress the sagging of the film, it must be used a coating solution obtained by setting a high viscosity.

  At this time, when the coating film to be formed is thin, in addition to the basic substrate and the amount of heating of the coating solution being small, the viscosity of the coating solution is low, and the viscosity variation due to temperature is relatively low. Viscosity due to the axial position of the substrate because the effect on the film thickness is small, or the time for heat exchange to occur is slow due to the slow coating pull-up speed and the difference in the degree of heat exchange depending on the site is difficult to appear in the coating area. It is difficult to make a difference. However, when it is necessary to increase the film thickness of the coating film to be formed, on the contrary, it is necessary to set at least the temperature of the substrate as high as possible, and the viscosity of the coating solution is high and the viscosity variation due to temperature affects the film thickness. The effect is large, or the time for heat exchange to occur is short because the coating pulling speed is fast, and the difference in the degree of heat exchange depending on the part in the coating region is likely to appear. Differences and film thickness differences resulting from this are likely to occur.

Here, as described above, it is required to increase the thickness of the coating film for the purpose of improving the strength of the charge transport layer in the recent multilayer electrophotographic photosensitive member, and a coating solution having a very high viscosity is required. In a situation where it is necessary to coat without film thickness sagging, the film thickness difference due to such a temperature difference is a big problem.
JP-A-3-181949 Japanese Patent Laid-Open No. 6-47327 JP 2000-194147 A

An object of the present invention is to provide a method for producing an electrophotographic photosensitive member having no film thickness sagging when forming a photosensitive layer by a dip coating method and having a uniform film thickness over the entire photosensitive layer, and thus excellent in image quality. There is to do.

In accordance with the present invention, there in the method for producing a photoreceptor for forming a coating film by the dip coating method that Ru pulling the該被application base body after immersion to be applied based material in the coating solution of an electrophotographic photoreceptor And
The該被application base body in dip coating, and held by the chucking device you have a heating means, the temperature Td of the coating substrate (℃), than the temperature Tp of the coating solution (℃) High and lower than the boiling point Tbs (° C.) of the dilution solvent contained in the coating solution by 20 ° C. or more,
In order to suppress a decrease in the thickness of the coating film due to a decrease in the viscosity of the coating solution caused by heat exchange between the coating solution and the substrate to be coated, the speed at which the substrate is pulled up is increased at least once or continuously. There is provided a method for producing an electrophotographic photosensitive member.

When forming a photosensitive layer on a substrate for an electrophotographic photosensitive member by dip coating, an electrophotographic photosensitive member having no film thickness sagging and having a uniform thickness over the entire photosensitive layer, and thus excellent image quality is manufactured. A method can be provided.

In the dip coating method, a coating film is formed by immersing the part to be coated once in the coating liquid and pulling it up at a fixed timing, and controlling the pulling speed, the viscosity of the coating liquid, the solid content, and the boiling point of the solvent. selection by determined physician degree of thickness sagging after coating start is. In order to minimize the degree of sagging, a means for heating at least one of the substrate and the coating solution is effective in order to further promote volatilization of the dilution solvent contained in the coating solution. In forming a thick coating film, a difference in film thickness that must be caused by this temperature difference is unavoidable due to the necessity of the temperature difference between the substrate and the coating solution as described above.

As a result of intensive studies on this problem, the present inventors have found that by using the present invention described above, it is possible to provide a method for producing an electrophotographic photosensitive member with a minimum film thickness sagging.

More specifically, the present invention will be described in more detail. When the substrate or the coating solution is heated and the temperature of the substrate is higher than that of the coating solution, both of them are immersed when the substrate is immersed in the coating solution. During this time, heat exchange occurs, and the coating solution in contact with or in the vicinity of the substrate is heated, and at the same time, the viscosity is lowered. Assuming that this state is applied, the coating thickness changes as follows: immediately after the start of coating, that is, at the upper end of the coating on the substrate, the coating solution first reaches a peak while dripping according to the coating environment. since by the heat exchange from the substrate over a longer time coating solution adhering to the substrate is to be calculated and the viscosity decreases as progress, it will decrease continuously.

  By overcoming this decrease and assuming a change in viscosity due to heat exchange, the coating pull-up speed can be increased at least once or continuously to form a flat coating film until the end of coating.

  Next, the control of the coating lifting speed will be described. In the present invention, the coating liquid that adheres to the substrate sequentially during the coating lifting is heat-exchanged for a longer time as the coating progresses, and the viscosity is lowered. It is based on making it. The increase, that is, acceleration is characterized by a method of accelerating stepwise at least once after the start of application pulling up or continuously accelerating for an arbitrary time. Furthermore, the film thickness of the coating film formed when the substrate is pulled up and separated from the coating liquid surface once reaches a peak due to dripping after the start of coating if the coating rising speed is constant. It is preferable not to reach the peak. The reason is that the film thickness peak distance that occurs later from the coating start position is due to the minimum sagging in the coating environment and the initial pulling speed. This is because the peak position is moved further to increase the insufficient film thickness region, that is, the region that does not function sufficiently as an electrophotographic photosensitive member.

  Further, among the acceleration methods, when referring to the method of continuous acceleration, a method of multiplying a constant or a variable according to the progress of time for an arbitrary speed, or a constant or variable for an arbitrary speed according to the progress of time. A method of adding is preferable. The constant or variable to be multiplied or added should be changed according to the coating solution to be used, the target film thickness, and other parameters.

In the present invention, when performing dip coating, the substrate, the coating solution, or both the substrate and the coating solution are heated to a temperature below the boiling point at which no bubbles of the coating solution are generated. Temperature Td of the substrate (℃), by which is kept 2 0 ° C. or more lower to the boiling point Tbs dilution solvents that are used in the coating liquid (℃), due to the temperature irregularity in the aforementioned liquid feeding system it is not a name that caused the bubbles. Further , when the temperature Tp (° C.) of the coating solution is kept at 5 ° C. or more lower than the temperature Td (° C.) of the substrate, the evaporation of the diluting solvent can be further promoted, and the effect of the present invention can be further obtained. easy.

The viscosity generated in viscosity liquid temperature 20 ° C. of the coating solution, when it is less 500 mPa · s or more over 3 000mPa · s, i.e. difficult maintaining high coating rate of rise is high viscosity, and the time difference between the aforementioned heat exchanger The effect of the present invention can be more easily obtained when coating is performed using a coating solution that greatly affects the thickness of the coating film to be finally formed.

  The target coating solution is effective for any layer coating solution constituting the multilayer electrophotographic photosensitive member, but it is the charge transport layer that most strongly needs to overcome sagging. .

  Examples of the binder resin contained in the coating liquid include polycarbonate, polyester, polyurethane, polysulfone, polyarylate, polyvinyl butyral, polyamide, phenoxy resin, acrylic resin, acrylonitrile resin, methacrylic resin, phenol resin, epoxy resin, and alkyd resin. It is done.

  The solvent is selected from those that are soluble in both the charge transport material and the binder resin and that have an appropriate boiling point. Examples include halogen solvents such as monochlorobenzene and dichloromethane, ketone solvents such as cyclohexanone and methyl ethyl ketone, and ether solvents such as dioxane and tetrahydrofuran, but other solvents may be used for the purpose of adjusting the drying speed and surface tension. Sometimes used. However, in an environment where coating is performed with the substrate and the coating solution heated, it is very preferable to select a solvent having a relatively high boiling point such as monochlorobenzene and to use it alone. By doing so, it is possible to prevent unexpected film surface turbulence and bubble generation due to excessive increase in volatilization rate, and by diluting the coating solution with a single solvent, high stability in the basic liquid state is achieved. You can expect.

  Then, the structure of the apparatus used for the manufacturing method of an electrophotographic photoreceptor is shown. The chucking device shown in FIG. 1 includes a chuck cylinder 4, a rubber O-ring 5, and an O-ring presser 6. A cylindrical heater 2 a is provided inside the chuck cylinder 4. The substrate 1 to be coated is held by the rubber O-ring 5 being spread by the O-ring press 6. In the present invention, a cylindrical heater may be used for warming chucking, and it is effective to use a heat storage fluid such as warm water or warm air as shown in FIG. In addition, as the material of the chuck cylinder 4, it is preferable to use a material having excellent thermal conductivity, represented by aluminum, stainless steel and other metals, and the amount of heat lost when the substrate comes into contact with the coating solution is reduced. Can make up for time. In order to obtain a larger heating effect on the base body, it is preferable that the holding mechanism portion centered on the O-ring 5 is downsized so that the cylindrical heater 2a can reach the upper end portion of the base body. Furthermore, in order to prevent the disturbance of the coating film to be formed, it is very important to make the heat conduction from the chucking device to the substrate uniform. The substrate 1 to be coated and the chuck cylinder 4, and the chuck cylinder 4 and the cylinder heater. The gap 2a is preferably 0.5 mm or less at all positions.

  Further, as shown in FIG. 2, a series of heating means including a cylindrical heater 2a built in the chucking device includes a coating tank heater 2b attached to the coating tank 7, and a coating applied to the coating liquid tank 8. Each of the liquid tank heaters 2c is connected to the heater amplifier 3d through the cables 3a to 3c.

FIG. 8 shows a schematic configuration of an electrophotographic apparatus provided with a process cartridge having an electrophotographic photosensitive member obtained by the manufacturing method of the present invention.

In FIG. 8, reference numeral 21 denotes a drum-shaped electrophotographic photosensitive member obtained by the production method of the present invention, which is rotationally driven around a shaft 22 at a predetermined peripheral speed (process speed) in the arrow direction. In the rotation process, the electrophotographic photosensitive member 21 is uniformly charged with a predetermined positive or negative potential on the peripheral surface thereof by the primary charging unit 23, and then is subjected to slit exposure or laser beam scanning exposure which is reflected light from the original. The exposure light 24 intensity-modulated in response to the time-series electric digital image signal of the target image information output from the exposure means (not shown) is received. In this way, electrostatic latent images corresponding to the target image information are sequentially formed on the peripheral surface of the electrophotographic photosensitive member 21.

  The formed electrostatic latent image is then visualized as a transferable particle image (toner image) by regular development or reversal development with charged particles (toner) in the developing means 25, and is electrophotographic from a paper supply unit (not shown). A toner image formed and supported on the surface of the electrophotographic photosensitive member 21 is transferred to the transfer material 27 that is taken out and fed between the photosensitive member 21 and the transfer unit 26 in synchronization with the rotation of the electrophotographic photosensitive member 21. Transfer is performed sequentially by the transfer means 26. At this time, a bias voltage having a polarity opposite to the charge held in the toner is applied to the transfer means from a bias power source (not shown).

  The transfer material 27 that has received the toner image transfer (in the case of a final transfer material (paper, film, etc.)) is separated from the electrophotographic photosensitive member surface, conveyed to the image fixing means 28, and subjected to a toner image fixing process. Printed out of the apparatus as an image formed product (print, copy). When the transfer material 27 is a primary transfer material (intermediate transfer material or the like), it is printed out after a fixing process after a plurality of transfer processes.

  The surface of the electrophotographic photosensitive member 21 after the transfer of the toner image is cleaned by the cleaning unit 29 after removing the deposits such as the transfer residual toner. In recent years, a cleanerless system has been studied, and the transfer residual toner can be directly collected by a developing device or the like. Further, after being subjected to charge removal processing by pre-exposure light 30 from a pre-exposure means (not shown), it is repeatedly used for image formation. When the primary charging unit 23 is a contact charging unit using a charging roller or the like, pre-exposure is not always necessary.

  In the present invention, a plurality of components such as the electrophotographic photosensitive member 21, the primary charging unit 23, the developing unit 25, and the cleaning unit 29 described above are housed in a container and integrally combined as a process cartridge. The process cartridge may be configured to be detachable from an electrophotographic apparatus main body such as a copying machine or a laser beam printer. For example, at least one of the primary charging unit 23, the developing unit 25, and the cleaning unit 29 is integrally supported together with the electrophotographic photosensitive member 21 to form a cartridge, and is attached to and detached from the apparatus main body using a guide unit 32 such as a rail of the apparatus main body. A flexible process cartridge 31 can be obtained.

  Further, when the electrophotographic apparatus is a copying machine or a printer, the exposure light 24 is a reflected light or transmitted light from the original, or the original is read by a sensor, converted into a signal, and a laser beam scanning performed according to this signal. The light emitted by driving the LED array or the liquid crystal shutter array.

The electrophotographic photosensitive member obtained by the production method of the present invention is not only used in electrophotographic copying machines, but also in electrophotographic application fields such as laser beam printers, CRT printers, LED printers, FAX, liquid crystal printers, and laser plate making. Is also widely applicable.

  EXAMPLES Next, although an Example demonstrates this invention concretely, this invention is not limited by these Examples.

Example 1
As the substrate to be coated, an aluminum cylindrical substrate (φ30 mm, length 254 mm) was prepared.

  Next, 100 parts by mass of conductive titanium oxide particle powder (trade name: ECT62, manufactured by Titanium Industry Co., Ltd.) having tin oxide containing antimony oxide as a coating layer, white titanium oxide powder having no conductivity ( Product name: SR-1T, manufactured by Sakai Kogyo Co., Ltd.) 100 parts by mass, phenol resin (trade name: Priorof J325, manufactured by Dainippon Ink & Chemicals) 130 parts by mass, silicone surfactant 0.02 mass Parts were mixed with 50 parts by mass of methanol and 50 parts by mass of methyl cellosolve, and this was subjected to a dispersion treatment with a sand mill for 6 hours to obtain a dispersion. This dispersion was applied to the outer surface of the cylindrical substrate by a dipping method, followed by drying and curing in an atmosphere at 150 ° C. for 30 minutes to form an intermediate layer having a thickness of 20 μm.

Next, 10 parts by mass of polyamide resin (trade name: Amilan CM8000, manufactured by Toray), 30 parts by mass of methoxymethylated 6 nylon resin (trade name: Toresin EF-30T, manufactured by Teikoku Chemical Co., Ltd.), 400 parts by mass of methanol A coating solution dissolved in 200 parts by mass of / n-butanol was dip coated and dried in hot air at 90 ° C. for 10 minutes to form an undercoat layer having a thickness of 0.68 μm.

Next, 9 parts by mass of a hydroxygallium phthalocyanine (HOGaPc) crystal having strong peaks at 7.4 ° ± 0.2 ° and 28.2 ° ± 0.2 ° of the Bragg angle 2θ in the characteristic X-ray diffraction of CuKα and polyvinyl A solution prepared by dissolving 3 parts by mass of butyral (trade name: ESREC BX-1, manufactured by Sekisui Chemical Co., Ltd.) in 100 parts of tetrahydrofuran was dispersed in a sand mill using 1 mmφ glass beads for 3 hours. 200 parts by mass of butyl acetate was added to this, diluted and recovered, and this was dip-coated on the undercoat layer and dried at 100 ° C. for 10 minutes to form a charge generation layer corresponding to 140 mg / m ^2. did.

  Next, 9 parts by mass of an amine compound represented by the following formula,

1 part by mass of an amine compound represented by the following formula,

10 parts by mass of a polyarylate (weight average molecular weight (Mw) is 130,000) resin obtained by copolymerizing repeating structural units represented by the following formula as a binder resin at a ratio of m: n = 7: 3,

Was dissolved in monochlorobenzene (boiling point: 132 ° C.) to prepare a coating solution. The viscosity of the coating solution at 20 ° C. was adjusted to 500 mPa · s by adjusting the content of the monochlorobenzene. Subsequently, this coating solution was applied to the aluminum cylindrical substrate by a dip coating method. At this time, the temperature of the coating solution is maintained at 31 ° C. using a warm water circulation mechanism as shown in FIG. 2, and a heating mechanism as shown in FIGS. 2 and 3 is inserted inside the substrate. The coating was performed while maintaining the temperature of the substrate surface at 35 ° C.

  At this time, the coating lifting speed was 200 mm / min as the initial speed, and then the coating speed was changed to 206 mm / min after coating at a constant speed until the lifting distance reached 30 mm. Thereafter, when the lifting distance reaches the 60 mm position, the lifting speed is 224 mm / min. When the lifting distance reaches the 100 mm position, the lifting speed is 244 mm / min. Similarly, at the 140 mm position, 262 mm / min. The film was applied at a speed of 280 mm / min at the 180 mm position and 296 mm / min at the 220 mm position. Note that the speed change when the lifting distance was 60 mm or later was set to 20 mm for all the distance settings required for acceleration. In this way, an electrophotographic photosensitive member having four layers was produced.

  Thereafter, the coated electrophotographic photosensitive member was dried at 130 ° C. for 1 hour, and the formed film thickness was measured with an eddy current film thickness measuring instrument (trade name: Fisherscope Type: MMS manufactured by Fischer). At this time, the film thickness at a coating pull-up distance of 40 mm was 25.0 μm. The other measurement results are shown in FIG.

  The electrophotographic photoreceptor thus produced was mounted on a Canon Co., Ltd. copier GP-40, and a halftone image was output for image evaluation. The evaluations were as follows: ○: no shading unevenness, Δ: slight shading unevenness, x: clear shading unevenness, xx: very clear shading unevenness. Further, for the purpose of evaluating the endurance ability, a halftone image was output with an upper limit of 50000 sheets, and the image was finished without causing defects, or the number of images at the time when defects were generated was recorded. The evaluation results are shown in Table 1.

(Example 2)
Except for using the method described below for the coating and lifting speed of the charge transport layer, coating was performed in the same manner as in Example 1, the film thickness was measured, and the image and durability were evaluated. The coating lifting speed was 200 mm / min as an initial speed, and then the coating was applied at a constant speed until the lifting distance reached 30 mm. Thereafter, the coating speed was increased by 2 mm / min every time the coating progress time advanced by 1 second. The measurement results are shown in FIG. 5 and the evaluation results are shown in Table 1.

(Example 3)
In the coating solution for the charge transport layer, 10 parts by mass of a polyarylate resin (weight average molecular weight (Mw) is 130,000) having a repeating structural unit represented by the following formula is used as the only binder resin constituted. A coating solution was prepared, and coating was performed in the same manner as in Example 2 except that the initial speed was adjusted so that the film thickness at a coating lifting distance of 30 mm was 25.0 μm, and the film thickness was measured. Images were evaluated. The measurement results are shown in FIG. 5 and the evaluation results are shown in Table 1.

Example 4
10 parts by mass of polycarbonate resin having a repeating structural unit represented by the following formula (trade name: Iupilon Z800, manufactured by Mitsubishi Engineering Plastics Co., Ltd.) as the only binder resin to be constructed in the coating solution for the charge transport layer Except that the coating solution was prepared using, coating was performed in the same manner as in Example 3, the film thickness was measured, and the image was evaluated. The measurement results are shown in FIG. 5 and the evaluation results are shown in Table 1.

(Example 5)
In the coating solution for the charge transport layer, 10 parts by mass of a polyarylate resin (weight average molecular weight (Mw) is 130,000) having a repeating structural unit represented by the following formula is used as the only binder resin constituted. Except that the coating solution was prepared, coating was performed in the same manner as in Example 3, the film thickness was measured, and the image was evaluated. The measurement results are shown in FIG. 5 and the evaluation results are shown in Table 1.

(Example 6)
In the application of the charge transport layer, the initial speed was adjusted so that the temperature of the coating liquid was 36 ° C., the temperature of the substrate was kept at 40 ° C., and the film thickness at the coating lifting distance was 30 mm was 25.0 μm. Thereafter, coating was performed at a constant speed until the lifting distance reached 30 mm. Thereafter, the coating speed was increased by 2.1 mm / min every time the coating progress time advanced by 1 second. Other than that, application was performed in the same manner as in Example 1, the film thickness was measured, and the image was evaluated. The measurement results are shown in FIG. 6 and the evaluation results are shown in Table 1.

(Example 7)
In the application of the charge transport layer, the temperature of the coating solution is set to 106 ° C., the temperature of the substrate is maintained at 110 ° C., and the initial speed is adjusted so that the film thickness at the coating lifting distance is 30 mm is 25.0 μm, Thereafter, coating was performed at a constant speed until the lifting distance reached 30 mm. Thereafter, the coating speed was increased by 4.8 mm / min every time the coating progress time advanced by 1 second. Other than that, application was carried out in the same manner as in Example 1, and the presence or absence of bubbles on the coating film was confirmed by an image after the completion of drying. The evaluation results are shown in Table 1.

(Example 8)
In the application of the charge transport layer, the temperature of the coating solution is set to 80 ° C., the temperature of the substrate is maintained at 90 ° C., and the initial speed is adjusted so that the film thickness at the coating lifting distance is 30 mm is 25.0 μm, Thereafter, coating was performed at a constant speed until the lifting distance reached 30 mm. Thereafter, the coating speed was increased by 4.2 mm / min every time the coating progress time increased by 1 second. Other than that, application was performed in the same manner as in Example 2, the film thickness was measured, and the image was evaluated. The measurement results are shown in FIG. 7, and the evaluation results are shown in Table 1.

Example 9
In application of the charge transport layer, monochlorobenzene was added so that the viscosity of the coating solution was 1000 mPa · s at 20 ° C. to prepare the coating solution, the temperature of the coating solution was set to 80 ° C., and the temperature of the substrate was set to 90 ° C. did. Furthermore, the coating was started at an initial speed of 200 mm / min, and the coating was performed at a constant speed until the lifting distance reached 30 mm. Thereafter, the coating speed was increased by 3.0 mm / min every time the coating progress time advanced by 1 second. Other than that, the coating was performed in the same manner as in Example 2, the film thickness was measured, and the image and durability were evaluated. In addition, solid content of this coating liquid was 10.8 mass%. The measurement results are shown in FIG. 4 and the evaluation results are shown in Table 1.

(Example 10)
In the application of the charge transport layer, monochlorobenzene was added so that the viscosity of the coating solution was 3000 mPa · s at 20 ° C. to prepare the coating solution, the temperature of the coating solution was set to 80 ° C., and the temperature of the substrate was set to 90 ° C. did. Furthermore, the application was started at an initial speed of 100 mm / min, and was applied at a constant speed until the lifting distance reached 30 mm. Thereafter, the coating speed was increased by 3.0 mm / min every time the coating progress time advanced by 1 second. Other than that, the coating was performed in the same manner as in Example 2, the film thickness was measured, and the image and durability were evaluated. In addition, solid content of this coating liquid was 24.3 mass%. The measurement results are shown in FIG. 4 and the evaluation results are shown in Table 1.

(Comparative Example 1)
Application of the charge transport layer was carried out in the same manner as in Example 1 except that the application was carried out while keeping the application lifting speed at 200 mm / min throughout, and the film thickness was measured to evaluate the image and durability. The measurement results are shown in FIG. 4 and the evaluation results are shown in Table 1.

(Comparative Example 2)
Application of the charge transport layer was carried out in the same manner as in Example 6 except that the application was carried out while maintaining the application lifting speed at the initial speed, and the film thickness was measured to evaluate the image and durability. The measurement results are shown in FIG. 6 and the evaluation results are shown in Table 1.

(Comparative Example 3)
In the application of the charge transport layer, coating was performed in the same manner as in Example 7 except that the temperature of the coating liquid was set to 116 ° C. and the temperature of the substrate was maintained at 120 ° C. After the drying was completed, bubbles were generated on the coating film. The presence or absence was confirmed by an image. The evaluation results are shown in Table 1.

(Comparative Example 4)
Application of the charge transport layer was carried out in the same manner as in Example 8 except that the application was carried out while keeping the application lifting speed at 200 mm / min throughout, and the film thickness was measured to evaluate the image and durability. The measurement results are shown in FIG. 7 and the evaluation results are shown in Table 1, respectively.

(Examples 1-6)
As shown in FIG. 4 to FIG. 6, the film thicknesses are formed without decreasing continuously even after the maximum value is shown after the start of coating. Further, as shown in Table 1, no shading unevenness occurred in the image, and in Examples 1 and 2, the endurance number did not cause a defect until the end.

(Example 7)
As shown in Table 1, no black spots due to bubbles were generated in the image, and no defects were generated until the end of the durability.

(Examples 8 to 10)
As shown in FIGS. 4 and 7, the film thicknesses are formed without continuing to decrease even after the maximum value is shown after the start of coating. Further, as shown in Table 1, no shading unevenness occurred in the images, and in Examples 9 and 10, no defects occurred until the end of the durability number.

(Comparative Example 1)
As shown in FIG. 4, the film thickness once showed a maximum value after the start of coating, and then decreased. The film thickness difference from Example 1 at a position of 220 mm from the start of application was 2.1 μm. Further, as shown in Table 1, it was confirmed that the density unevenness in the image slightly increased in density from the first half to the second half of the electrophotographic photosensitive member coating. Image fogging occurred in the latter half of the electrophotographic photosensitive member coating when the durability was about 46,200.

(Comparative Example 2)
As shown in FIG. 6, the film thickness once showed a maximum value after the start of coating, and then decreased. The film thickness difference from Example 6 at the position of 220 mm from the start of application was 2.6 μm. Further, as shown in Table 1, it was confirmed that the density unevenness in the image clearly increased in density from the first half to the second half of the electrophotographic photosensitive member coating. Image fogging occurred in the latter half of the electrophotographic photosensitive member coating when the durability was 39,500.

(Comparative Example 3)
As shown in Table 1, it was confirmed that black spots caused by the generation of bubbles were 2 points of φ0.7 mm or more and 4 points of less than φ0.7 mm.

(Comparative Example 4)
As shown in FIG. 7, the film thickness once showed a maximum value after the start of coating, and then decreased. The film thickness difference from Example 6 at a position of 220 mm from the start of application was 4.5 μm. Further, as shown in Table 1, it was confirmed that the density unevenness in the image was very strongly increased from the first half to the second half of the electrophotographic photosensitive member coating. Image fogging occurred in the latter half of the electrophotographic photosensitive member coating when the durable number was around 27,700.

It is a schematic block diagram of the chucking apparatus using the heater in this invention. It is a schematic block diagram of the heating apparatus in this invention. It is a schematic block diagram of the chucking apparatus using the thermal storage fluid in this invention. It is a figure which shows the application result of Example 1, Example 9, Example 10, and Comparative Example 1. FIG. It is a figure which shows the application result of Examples 2-5. It is a figure which shows the application result of Example 6 and Comparative Example 2. It is a figure which shows the application result of Example 8 and Comparative Example 4. It is a figure which shows the example of schematic structure of the electrophotographic apparatus provided with the process cartridge which has the electrophotographic photoreceptor obtained by the manufacturing method of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Substrate to be coated 2a Cylindrical heater 2b Coating tank heater 2c Coating liquid tank heater 3a to c Heater cable 3d Heater amplifier 4 Chuck cylinder 5 Rubber O-ring 6 O-ring press 7 Coating tank 8 Coating liquid tank 9 Filter unit 10 Feed pump 11 Heat storage fluid circulation path

Claims (4)

A process for producing an electrophotographic photosensitive member for forming a coating film by the dip coating method that Ru pulling the該被application base body after immersion to be applied based material in the coating solution of an electrophotographic photoreceptor,
The該被application base material when performing dip coating, and held in heating means you have a chucking device, the temperature Td of the coating substrate (° C.), the coating solution temperature Tp (° C.) Higher than the boiling point Tbs (° C.) of the dilution solvent contained in the coating solution by 20 ° C. or more,
In order to suppress a decrease in the thickness of the coating film due to a decrease in the viscosity of the coating solution caused by heat exchange between the coating solution and the substrate to be coated, the speed at which the substrate is pulled up is increased at least once or continuously. A method for producing an electrophotographic photoreceptor, characterized by comprising: The coating liquid temperature Tp and (° C.), the manufacturing method of the electrophotographic photosensitive member according to claim 1, wherein the lower 5 ° C. or more with respect to the temperature Td of the coating substrate (° C.). The viscosity of the coating solution, the manufacturing method of the electrophotographic photosensitive member according to claim 1 or 2 or less 5 MPa · s or more over 3 000mPa · s temperature of the coating solution at the time of 20 ° C.. A charge generation layer is formed on the surface of the substrate to be coated immersed in the coating solution, and the coating solution is a coating solution used to form a charge transport layer, and the coating film is charged. The method for producing an electrophotographic photosensitive member according to claim 1, wherein the method is a coating film of a transport layer.