JP2023158926A - Manufacturing method of coated film, manufacturing method of electrophotographic photoreceptor, manufacturing apparatus of coated film, electrophotographic photoreceptor and image formation apparatus - Google Patents

Abstract

To provide a manufacturing method of a coated film which can suppress nonuniform film thickness due to not only a coating condition but also an environmental condition or the like after coating and at the time of drying.SOLUTION: The present invention relates to a manufacturing method of a coated film including the steps of: applying coating liquid containing an organic solvent to a base body; and drying the applied coating liquid. The manufacturing method includes the step of changing a manufacturing condition according to the state of the solvent vapor generated with vaporization of the organic solvent observed in the drying step.SELECTED DRAWING: Figure 1

Description

The present invention relates to a coating film manufacturing method, an electrophotographic photoreceptor manufacturing method, a coating film manufacturing apparatus, an electrophotographic photoreceptor, and an image forming apparatus.

A coating liquid containing an organic solvent and a film-forming material is applied to a substrate, the wet film is dried to volatilize the organic solvent to form a wet film, and then the wet film is cured to form a coating containing a film-forming material. Methods of forming films on the surface of substrates are known. In this method, a smooth and uniformly thick wet film is formed by applying a coating liquid, which is then cured to form a coating film, making it possible to form a smooth and uniformly thick coating film. .

However, even with the above coating film formation method, there may be variations in the thickness of the applied coating liquid, or the surrounding environment may change over time from the time it is applied until the end of the drying process where a wet film is formed. As a result, variations in thickness (uneven film thickness) may occur in the formed coating film. Since uneven film thickness causes variations in product quality, methods for forming coating films that can suppress the occurrence of uneven film thickness are being studied.

For example, in Patent Document 1, after applying a coating liquid onto a conductive substrate by a dip coating method, the thickness of the wet coating film is measured before drying, and the thickness of the coating film after drying is determined from the film thickness. Estimating the thickness. The patent claims that by adjusting the amount of coating liquid applied during the next coating based on the estimated film thickness, it is possible to make the thickness of the coating film uniform for each coating lot and to produce photoreceptors with constant characteristics. It is described in Document 1.

Similarly, in Patent Document 2, the film thickness distribution of a coating film in a wet state after coating and before drying is measured. Patent Document 2 describes that the thickness distribution of the coating film can also be made uniform by adjusting the coating amount of the coating liquid during the next coating based on the results of the above measurement.

Japanese Patent Application Publication No. 2001-027815 Japanese Patent Application Publication No. 2003-270804

Patent Document 1 and Patent Document 2 disclose that after applying a coating liquid, the film thickness or film thickness distribution before drying is measured to estimate the film thickness or film thickness distribution after drying, and based on this estimation result, the coating film is A method is described in which the thickness of the coating film is made uniform by adjusting the coating amount and the like. However, although these methods can suppress unevenness in film thickness due to changes in coating conditions to some extent, unevenness in film thickness due to environmental conditions after coating and during drying can be suppressed to some extent. could not be suppressed.

The present invention has been made in view of the above problems, and provides a method for producing a coating film that can suppress unevenness in film thickness caused not only by coating conditions but also by environmental conditions after coating and during drying, and a method for producing a coating film. A method for manufacturing an electrophotographic photoreceptor that includes a manufacturing method in the process, a coating film manufacturing apparatus capable of carrying out the method, an electrophotographic photoreceptor having a coating film produced by the method, and an image having the electrophotographic photoreceptor. Its purpose is to provide a forming device.

One aspect of the present invention for achieving the above object relates to a method for producing a coating film, which includes the steps of applying a coating liquid containing an organic solvent to a substrate, and drying the applied coating liquid. The method further includes a step of changing manufacturing conditions depending on the state of solvent vapor generated by volatilization of the organic solvent observed in the drying step.

Further, another aspect of the present invention for achieving the above object relates to a method for manufacturing an electrophotographic photoreceptor, which carries out the method for manufacturing the coating film.

Another aspect of the present invention for achieving the above object includes an application part that applies a coating liquid containing an organic solvent to a substrate, a drying part that dries the applied coating liquid, and a drying part that dries the applied coating liquid. The present invention relates to an apparatus for producing a coating film, which includes a monitor section that monitors vapor produced by volatilization of a liquid, and a control section that changes production conditions according to the monitored state of the vapor.

Further, another aspect of the present invention for achieving the above object is an electrophotographic photographic film having a coating film produced by the above-mentioned coating film production method or a coating film produced using the above-mentioned coating film production apparatus. Regarding photoreceptors.

Another aspect of the present invention for achieving the above object relates to an image forming apparatus having the electrophotographic photoreceptor.

According to the present invention, there is provided a method for producing a coating film that can suppress nonuniformity in film thickness caused not only by coating conditions but also by environmental conditions after coating and during drying, and an electronic method that includes the method for producing the coating film in the process. Provided are a method for producing a photographic photoreceptor, a coating film production apparatus capable of carrying out the method, an electrophotographic photoreceptor having a coating produced by the method, and an image forming apparatus including the electrophotographic photoreceptor.

FIG. 1 is an exemplary flow diagram of a method for manufacturing a coating according to one embodiment of the present invention. FIG. 2 is a partial cross-sectional view showing an exemplary layer structure of an electrophotographic photoreceptor according to an embodiment of the present invention. FIG. 3 is a schematic diagram showing an example of a coating film manufacturing apparatus according to an embodiment of the present invention, which applies a coating liquid to a substrate by dipping. FIG. 4 is a block diagram showing the configuration of each functional unit in a coating film manufacturing apparatus according to an embodiment of the present invention. FIG. 5 is a schematic diagram showing another example of a coating film manufacturing apparatus according to an embodiment of the present invention, which applies a coating liquid to a substrate by dipping. FIG. 6 is a schematic diagram showing an exemplary configuration of an image forming apparatus having electrophotography according to an embodiment of the present invention.

1. Coating Film Manufacturing Method and Coating Film Manufacturing Apparatus FIG. 1 is an exemplary flow diagram of a coating film manufacturing method according to an embodiment of the present invention. As shown in FIG. 1, the method for manufacturing a coating film in this embodiment includes a step of applying a coating liquid containing an organic solvent to a substrate (step S110), and a step of drying the applied coating liquid (step S120). , a step of changing manufacturing conditions according to the state of solvent vapor generated by volatilization of the organic solvent observed in the drying step (step S130), and a step of optionally forming a coating film (step S140). ) and has. Each step will be explained below.

Hereinafter, in this embodiment, an example of forming each layer constituting an electrophotographic photoreceptor (hereinafter also simply referred to as "photoreceptor") used for image formation by electrophotography will be described. However, the layer structure of the photoreceptor is not limited to the photoreceptor 100 shown in FIG. It can be applied to any coating film manufacturing method that forms a coating film by drying.

FIG. 2 is a partial cross-sectional view showing an exemplary layer structure of the photoreceptor 100. The photoreceptor 100 in this embodiment includes a conductive substrate 110, an undercoat layer (UCL) 120, a charge generation layer (CGL) 130, a charge transport layer (CTL) 140, and an overcoat layer (OCL), which are laminated in this order. ) 150.

The conductive substrate 110 may be a support for each of the above-mentioned layers constituting the photoreceptor 100 and is made of a conductive material. Examples of the conductive substrate 110 include a substrate made of metal such as aluminum, copper, chromium, nickel, zinc, and stainless steel formed into a drum shape or sheet shape, a substrate made of metal foil such as aluminum and copper laminated to a plastic film, and aluminum. , indium oxide, tin oxide, etc., on a plastic film, and substrates with a conductive layer formed by applying a conductive substance alone or together with a binder resin to the surface of metal, plastic film, paper, etc. is included.

Each of the undercoat layer 120, charge generation layer 130, charge transport layer 140, and overcoat layer 150 is formed by a method including a step of applying a coating liquid for forming each layer to the substrate and drying it. It is formed.

Note that the substrate is a layer that is in contact with the applied coating liquid, that is, a layer that is located inside and in contact with the layer to be formed. When forming the undercoat layer 120, the base is the conductive base 110, when forming the charge generation layer 130, the base is the undercoat layer 120, and when forming the charge transport layer 140, the base is the conductive base 110. When forming the charge generation layer 130 and the overcoat layer 150, the substrate is the charge transport layer 140.

The above-mentioned coating liquid is a solution or dispersion in which resins and additives serving as materials for each of these layers are dissolved or dispersed in an organic solvent.

For example, when forming the undercoat layer 120, the coating liquid includes an organic solvent, a binder resin dissolved in the organic solvent, and conductive particles or metal oxide particles for resistance adjustment dispersed in the organic solvent. It can be made into a dispersion liquid containing.

Examples of the above-mentioned organic solvents include methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butanol, t-butanol, and sec-butanol, which have 1 to 1 carbon atoms and are organic solvents with excellent solubility of the binder resin. Contains 4 alcohols. Further, the organic solvent may contain a co-solvent such as benzyl alcohol, toluene, dichloromethane, cyclohexanone, and tetrahydrofuran for adjusting the dispersibility of the conductive particles or metal oxide particles.

Examples of the binder resin include casein, polyvinyl alcohol, nitrocellulose, ethylene-acrylic acid copolymer, polyamide resin, polyurethane resin, and gelatin.

Examples of such conductive particles include particles such as tin-doped indium oxide, antimony-doped tin oxide, and zirconium oxide. Examples of the metal oxides include particles of alumina, zinc oxide, titanium oxide, tin oxide, antimony oxide, indium oxide, bismuth oxide, and the like. The number average primary particle diameter of the conductive particles or metal oxide particles can be, for example, 0.01 μm or more and 0.3 μm or less, preferably 0.01 μm or more and 0.1 μm or less.
In this specification, the number average particle diameter of particles is determined by reading an SEM photograph taken using a scanning electron microscope (SEM) at a magnification of 10,000 times into a scanner, and using an image processing analysis device "LUZEX AP" (Co., Ltd.). This is the average value of the Feret diameter in the horizontal direction for 100 particles in the image data subjected to the binarization process using the image data (manufactured by Nireco).

Further, when forming the charge generation layer 130, the coating liquid may be a dispersion liquid containing an organic solvent, a binder resin dissolved in the organic solvent, and a charge generation substance dispersed in the organic solvent. can.

Examples of the above organic solvents include toluene, xylene, dichloromethane, 1,2-dichloroethane, methyl ethyl ketone, cyclohexane, ethyl acetate, t-butyl acetate, methanol, ethanol, propanol, butanol, methyl cellosolve, 4-methoxy-4-methyl -2-pentanone, ethyl cellosolve, tetrahydrofuran, 1-dioxane, 1,3-dioxolane, pyridine, diethylamine, and the like.

Examples of the binder resin include polystyrene resin, polyethylene resin, polypropylene resin, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, polyvinyl butyral resin, epoxy resin, polyurethane resin, phenol resin, polyester resin, alkyd resin, These include polycarbonate resins, silicone resins, melamine resins, polyvinylcarbazole resins, and the like. Further, the binder resin may be a copolymer containing two or more of these, such as a vinyl chloride-vinyl acetate copolymer resin and a vinyl chloride-vinyl acetate-maleic anhydride copolymer resin.

Examples of the charge generating materials mentioned above include azo raw materials such as Sudan Red and Diane Blue, quinone pigments such as pyrenequinone and anthinthrone, quinocyanine pigments, perylene pigments, indigo pigments such as indigo and thioindigo, pyranthrone and diphthaloylpyrene. Includes polycyclic quinone pigments and phthalocyanine pigments.

Further, when forming the charge transport layer 140, the coating liquid is a dispersion liquid containing an organic solvent, a binder resin dissolved in the organic solvent, and a charge transport substance dissolved or dispersed in the organic solvent. be able to.

Examples of the organic solvents mentioned above include toluene, xylene, dichloromethane, 1,2-dichloroethane, methyl ethyl ketone, cyclohexanone, ethyl acetate, butyl acetate, methanol, ethanol, propanol, butanol, tetrahydrofuran, 1,4-dioxane, 1,3- These include dioxolane, pyridine, and diethylamine.

Examples of the above binder resin include various polycarbonate resins such as BPA (bisphenol A) type, BPZ (bisphenol Z) type, dimethyl BPA type, and BPA-dimethyl BPA copolymer type, polyacrylate resin, polyester resin, polystyrene resin, and styrene resin. -Includes acrylonitrile copolymer resins, polymethacrylate ester resins, and styrene-methacrylate ester copolymer resins.

Examples of the charge transport substance include triphenylamine derivatives, hydrazone compounds, styryl compounds, benzidine compounds, and butadiene compounds.

Further, when forming the overcoat layer 150, the coating liquid contains an organic solvent, a polyfunctional radically polymerizable compound and a polymerization initiator dissolved or dispersed in the organic solvent, and inorganic particles dispersed in the organic solvent. It can be a dispersion liquid containing.

Examples of the above organic solvents include methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butanol, t-butanol, sec-butanol, benzyl alcohol, toluene, xylene, dichloromethane, methyl ethyl ketone, cyclohexane, ethyl acetate, butyl acetate. , methyl cellosolve, ethyl cellosolve, tetrahydrofuran, 1-dioxane, 1,3-dioxolane, pyridine and diethylamine.

Examples of the above-mentioned polyfunctional radically polymerizable compounds include known monomers or oligomers having two or more radically polymerizable functional groups such as vinyl groups, acryloyl groups, and methacryloyl groups in the molecule. The polymerization initiator may be any known initiator as long as it initiates radical polymerization.

Examples of the inorganic particles include particles of silica, magnesium oxide, zinc oxide, lead oxide, zirconium oxide, tin oxide, titania, niobium oxide, molybdenum oxide, vanadium oxide, and the like. Note that these inorganic particles may be surface-modified with a surface treatment agent having a radically polymerizable functional group. Examples of the above-mentioned surface treatment agents include silane coupling agents that have radically polymerizable functional groups such as vinyl groups, acryloyl groups, and methacryloyl groups, and functional groups that react with hydroxy groups present on the surface of inorganic particles. and titanium coupling agents. The number average particle size (secondary particle size when the inorganic particles are secondary particles) of the inorganic particles can be, for example, 0.1 μm or more and 0.5 μm or less.

In this embodiment, the undercoat layer 120, charge generation layer 130, charge transport layer 140, and overcoat layer 150 are formed by a method including each step of the flow shown in FIG.

In this embodiment, the undercoat layer 120, charge generation layer 130, charge transport layer 140, and overcoat layer 150 are formed by a method including each step of the flow shown in FIG.

1-1. Step of applying coating liquid (step S110)
In this step, a coating liquid containing an organic solvent is applied to the substrate.

The applied coating liquid is the coating liquid used to form each layer, as described above. All of these coating liquids contain organic solvents.

The method of applying the coating liquid is not particularly limited, and known methods such as dip coating method, spray coating method, spinner coating method, bead coating method, blade coating method, beam coating method, slide hopper method, and circular slide hopper method can be used. Can be adopted.

Among these, a method such as a dip coating method in which the substrate is immersed in the coating liquid stored in a coating tank to apply the coating liquid to the substrate is a method of applying the coating liquid in the step of changing the manufacturing conditions (step S130) described later. It is easy to change the state of the applied coating liquid, and it is easy to control minute changes in the state of the applied coating liquid. Therefore, the present embodiment can exhibit its effects more effectively when applying the coating liquid by immersing the substrate in the coating liquid.

Conditions for applying the coating liquid may be determined depending on the type of coating liquid to be applied and the characteristics required of the layer to be formed. Examples of coating liquid application conditions include coating liquid concentration, coating liquid temperature, coating liquid application amount, coating liquid stirring speed and stirring time, substrate temperature, ambient temperature, atmospheric humidity, presence or absence of ventilation, and ventilation. This includes, but is not limited to, the strength of Note that the conditions for applying the coating liquid are usually determined within a certain range, and can be changed as appropriate within the range.

For example, the application time of the coating liquid may be set depending on the thickness of the layer to be formed. For example, in this embodiment, the layer thickness of the undercoat layer 120 is 0.1 μm or more and 15 μm or less, preferably 0.3 μm or more and 10 μm or less, and the layer thickness of the charge generation layer 130 is 0.01 μm or more and 5 μm or less, preferably The layer thickness of the charge transport layer 140 is 5 μm or more and 40 μm or less, preferably 10 μm or more and 30 μm or less, and the layer thickness of the overcoat layer 150 is 0.2 μm or more and 10 μm or less, preferably 0.05 μm or more and 3 μm or less. It can be 5 μm or more and 6 μm or less. By changing the application time of the coating liquid, the amount of the coating liquid applied when forming each layer can be changed so that layers with these thicknesses are formed.

FIG. 3 is a schematic diagram showing an example of a coating film manufacturing apparatus according to the present embodiment, which applies a coating liquid to a substrate by dipping. FIG. 4 is a block diagram showing the configuration of each functional section in the coating film manufacturing apparatus according to this embodiment. As shown in FIGS. 3 and 4, the coating film manufacturing apparatus 300 includes a coating liquid tank 312 that stores the coating liquid, a coating liquid tank 314 that applies the coating liquid to the substrate 370, and a coating liquid tank 314 that stores the coating liquid. A dilution solvent tank 315 that stores a dilution solvent for dilution, a dilution solvent pump 315a that controls the flow rate of the dilution solvent flowing from the dilution solvent tank 315 to the coating liquid tank 314, and receives the coating liquid overflowing from the coating liquid tank 314. It has a coating liquid receiving tank 316, a coating liquid pump 318 that controls the flow rate of the coating liquid circulating between the coating liquid tank 312 and the coating liquid tank 314, and a drying section 320 that dries the substrate 370 to which the coating liquid has been applied. . As shown in FIG. 4, a coating liquid tank 312, a coating liquid tank 314, a diluted solvent tank 315, a diluted solvent pump 315a, a coating liquid receiving tank 316, and a coating liquid pump 318 are connected to a coating part 310 that applies coating liquid to a substrate 370. It is. Further, the coating liquid tank 312 has a stirring part 313, and is configured to be able to stir the coating liquid inside the coating liquid tank 312 by the stirring part 313. The coating film manufacturing apparatus 300 further includes an infrared camera 332 that observes solvent vapor generated by volatilization of the organic solvent during drying, and a substrate transport unit 340 that immerses the substrate 370 in the coating liquid tank 314 and pulls it up after immersion. It has an air conditioning section 350 that adjusts environmental conditions such as temperature, humidity, air pressure, and ventilation in the booth where the coating film is formed, and a control section 360 that controls the operations of each of the above-mentioned components. The infrared camera 332 is a monitor unit 330 that monitors the state of solvent vapor.

In the coating film manufacturing apparatus 300 shown in FIGS. 3 and 4, the coating liquid in the coating liquid tank 312 is supplied to the coating liquid tank 314 by the coating liquid pump 318 whose operating pressure is controlled by the control unit 360. The supplied coating liquid overflows from the coating liquid tank 314 and is received in the coating liquid receiving tank 316, and is further returned from the coating liquid receiving tank 316 to the coating liquid tank 312. At this time, the coating liquid pump 318 controls the operating pressure of the coating liquid pump 318 so that the coating liquid supplied to the coating liquid tank 314 always overflows. Thereby, the liquid level in the coating liquid tank 314 can always be kept at the same height. Note that a filter (not shown) may be provided in the flow path from the coating liquid tank 312 to the coating liquid tank 314 to remove unnecessary substances in the coating liquid.

Further, the coating liquid tank 312, the coating liquid tank 314, and the diluting solvent tank 315 are provided with a temperature adjustment mechanism (not shown), and under the control of the control unit 360, the temperature inside the coating liquid tank 312 and the coating liquid tank are controlled. The temperature of the coating liquid inside 314 can be adjusted. Further, the coating liquid tank 312 is provided with a stirring unit 313, which continuously or intermittently stirs the coating liquid in the coating liquid tank 312 under the control of the control unit 360. Stir to homogenize the concentration. Note that the stirring by the stirring section 313 may be performed before applying the coating liquid.

In this step, the substrate transport section 340 transports the substrate 370 whose surface temperature has been adjusted to a predetermined temperature and immerses it in the coating liquid in the coating liquid tank 314 under the control of the control section 360 . After immersion for a predetermined time, the base body 370 is pulled up in the vertical direction at a speed controlled by the control unit 360. The control unit 360 controls the immersion time and the speed of pulling up according to the thickness of the coating film to be formed. Note that the temperature of the surface of the substrate 370 to be immersed can be adjusted by adjusting the atmospheric temperature of the substrate 370 storage chamber shown in the accompanying drawings.

At this time, the air conditioning section 350 adjusts the atmospheric environment in the booth under the control of the control section 360 so that the temperature, humidity, atmospheric pressure, wind direction, and air volume are set to predetermined values.

1-2. Step of drying the coating liquid (step S120)
In this step, the coating liquid applied to the substrate is dried.

After being immersed in the coating liquid, the substrate 370 pulled up by the substrate transport section 340 is vertically pulled up as it is, and passes through the drying section 320 arranged vertically above the coating liquid tank 314 . In the drying section 320, the organic solvent in the coating liquid applied to the substrate 370 is evaporated, and the coating liquid is air-dried until the coating liquid is dry to the touch, in which the coating liquid does not stick to the finger even when the surface is touched with a finger. let

In this embodiment, in this step, the state of solvent vapor generated by volatilization of the organic solvent is observed.

The type of state of the solvent vapor to be observed is not particularly limited, and may include the overall amount of volatilization, unevenness in the amount of volatilization from position to position, temperature, flow direction, etc.

Observation of the solvent vapor may be performed by visualizing the flow of the solvent vapor using dry ice or smoke, or may be performed using an ultrasonic camera, laser, or the like. In this embodiment, compared to these methods, only the solvent vapor can be observed without simultaneously measuring other air flows, and therefore an infrared camera sensitive to the absorption wavelength band of solvent vapor is used for observation. Note that when the temperature difference between the temperature of the solvent vapor and the ambient temperature is small, a high-resolution infrared camera such as that described in Japanese Patent No. 6,245,418 may be used.

The state of the solvent vapor may be observed immediately after applying the coating liquid to the substrate 370 (immediately after pulling up the substrate 370 immersed in the coating liquid), or after a predetermined period of time has passed after applying the coating liquid. This may be carried out after the state of the solvent vapor has stabilized to some extent. Further, the observation may be performed continuously, the observation may be performed multiple times with the elapsed time shifted, or the same position may be observed from different angles.

Observation of the state of solvent vapor by these methods can be performed without contact. Therefore, worker safety is also high.

FIG. 5 is a schematic diagram showing another example of the coating film manufacturing apparatus according to the present embodiment, which applies a coating liquid to a substrate by dipping. In a coating film manufacturing apparatus 300 shown in FIG. 5, a drying section 320 has a coating 322 that covers a substrate 370, and dries the substrate 370 to which a coating liquid has been applied inside the coating 322. The coating 322 stops or stabilizes the flow of air around the substrate 370 to which the coating liquid is applied, and makes the flow of solvent vapor inside the coating 322 uniform. Furthermore, by providing one or more exhaust ports 322a or 322b in the coating 322, the flow of solvent vapor exhausted from the interior of the coating 322 can be made uniform. By making the flow of the solvent vapor uniform with these, the organic solvent can be volatilized more uniformly from the substrate 370 to which the coating liquid has been applied, and the thickness of the coating film can be made more uniform.

1-3. Step of changing manufacturing conditions (step S130)
In this step, manufacturing conditions are changed depending on the state of solvent vapor observed in the step of drying the coating liquid (step S120).

The thickness of the coating film to be formed can be estimated from the state of the solvent vapor observed above. Therefore, the manufacturing conditions may be changed depending on the observed state of the solvent vapor so that the thickness of the coating film falls within a desired range. Examples of the manufacturing conditions include conditions for applying the coating liquid by the application unit 310, for example, immersion conditions when the substrate 370 is immersed in the coating liquid, conditions for stirring the coating liquid in the coating liquid tank 312, and conditions for applying the coating liquid by the coating liquid pump 318. conditions for drying the coating liquid by the drying section 320, conditions for conveying the substrate 370 by the substrate conveying section 340, for example, the residence time of the substrate 370 inside the coating 322, conditions for adjusting the environment by the air conditioning section 350, etc. It will be done. Only one of these conditions may be changed, or a plurality of conditions may be changed simultaneously.

For example, when the observed amount of solvent vapor is large, it is presumed that the amount of applied coating liquid is large and the film thickness is thick. Alternatively, it is also presumed that conditions are such that the organic solvent is likely to volatilize due to a large amount of air hitting the substrate 370, and that unevenness in film thickness is likely to occur due to the influence of airflow. In such a case, each manufacturing condition may be changed so that the amount of coating liquid applied to the substrate 370 is reduced, or so that unevenness in film thickness is less likely to occur. As long as this is the case, there are no particular limitations on which conditions should be changed.

Specifically, in the step of applying the coating liquid (step S110), the temperature of the coating liquid in the coating liquid tank 312 may be increased to lower the viscosity. Alternatively, the surface temperature of the substrate 370 before being immersed in the coating liquid may be made higher to make the amount of coating liquid applied from the substrate 370 more uniform.

Note that when the coating liquid is applied by a method other than dipping, the conditions may be changed depending on the method. For example, the amount of coating liquid applied to the base 370 may be reduced by reducing the amount of coating liquid supplied by spraying or by increasing the pressure during smoothing with a scraper after supplying the coating liquid. .

Furthermore, the viscosity and concentration of the coating liquid may be made uniform by increasing the speed of stirring by the stirring unit 313 in the coating liquid tank 312 or by lengthening the duration of stirring. Alternatively, the amount of coating liquid applied may be reduced by slowing down the rate at which the substrate conveying section 340 pulls up the substrate 370 immersed in the coating liquid tank 314.

In addition, in the step of drying the coating liquid (step S120), the air conditioning unit 350 lowers the temperature in the booth, lowers the humidity, lowers the air pressure, and reduces the amount of air blown into the booth to dry the film. In order to prevent thickness unevenness, the effect of air blowing may be reduced. Alternatively, in order to reduce the unevenness of the coating film thickness, the length of the coating 322 shown in FIG. The time during which the substrate 370 passes may be increased to more uniformly volatilize the solvent vapor during the drying process.

Conversely, when the observed amount of solvent vapor is small, it is presumed that the amount of applied coating liquid is small and the film thickness is thin. In such a case, increase the amount of coating liquid applied to the substrate 370, or increase the viscosity and concentration of the coating liquid so that even if the amount of coating liquid applied is small, the thickness of the coating film will increase. All you have to do is change each manufacturing condition. As long as this is the case, there are no particular limitations on which conditions should be changed.

Specifically, in the step of applying the coating liquid (step S110), the temperature of the coating liquid in the coating liquid tank 312 is lowered to increase the viscosity, or the substrate 370 immersed in the coating liquid tank 314 is transferred to the substrate conveying section 340. The amount of coating liquid applied may be increased by increasing the pulling speed.

Note that when the coating liquid is applied by a method other than dipping, the conditions may be changed depending on the method. For example, the amount of coating liquid applied to the base 370 may be increased by increasing the amount of coating liquid supplied by spraying or by lowering the pressure during smoothing with a scraper after supplying the coating liquid. good.

Furthermore, the concentration of the coating liquid may be increased by reducing the total amount of diluting solvent supplied by the diluting solvent pump 315a and reducing the amount of diluting solvent added in the coating liquid tank 312.

Furthermore, the length of the covering body 322 shown in FIG. Alternatively, the distance between the discharge port 322a and the discharge port 322b may be increased to reduce dripping of the coating liquid.

Incidentally, since the solvent vapor generated by volatilization of the hydrocarbon-based organic solvent used in this embodiment is normally heavier than air, after leaving the base 370, it moves downward in the vertical direction. When this downward movement of the solvent vapor is gradual and uniform, it can also be determined that the flow of the solvent vapor is in a desirable state.

On the other hand, when the observed flow of solvent vapor differs from the desired flow, or when the flow of solvent vapor differs for each of a plurality of points, it is presumed that unevenness in film thickness is likely to occur. In such a case, each manufacturing condition may be changed so that the drying conditions of the coating liquid are uniform, or the amount and concentration distribution of the coating liquid are uniform. As long as this is the case, there are no particular limitations on which conditions should be changed.

Specifically, the flow of air in the booth may be changed by changing the air blowing into the booth by the air conditioning unit 350 so that the flow of solvent vapor becomes a normal flow and a uniform flow. For example, the amount of air supplied into the booth from the air supply port and the amount of air discharged from the air outlet can be changed. If the booth has multiple supply ports or multiple discharge ports, finely adjust the air flow in the booth by changing the supply or discharge amount for each supply port or each discharge port. You can also do that. Alternatively, you can check whether each supply port and exhaust port are operating normally, or check to see if there are any cracks in the walls or ceiling that may cause unexpected air leaks from inside the booth. good.

Further, at this time, changes may be made to make it difficult for film thickness unevenness to occur. Specifically, the viscosity and concentration of the coating liquid may be made uniform by increasing the speed of stirring by the stirring unit 313 in the coating liquid tank 312 or by increasing the duration of stirring. Alternatively, the rate at which the substrate 370 immersed in the coating liquid tank 314 is pulled up by the substrate conveying unit 340 may be slowed down to increase the residence time in the coating 322, or the distance between the outlet 322a and the outlet 322b may be narrowed. The amount of dripping of the liquid may be increased to prevent unevenness in the amount of application of the coating liquid.

In addition, if the amount of solvent vapor observed is excessive or insufficient, or the difference in the amount of solvent vapor from one part to another is extremely large, and it is determined that the product cannot be made into a good product even if the manufacturing conditions are changed. In this case, the part may be determined to be defective and not sent to the next process.

According to this embodiment, it is possible to suppress nonuniformity in film thickness caused not only by coating conditions but also by environmental conditions after coating and during drying.

In addition, by changing the conditions of the step of drying the coating liquid (step S120), the manufacturing conditions of the coating film itself applied to the substrate whose volatilized solvent vapor is observed can be controlled in real time, making it possible to control the manufacturing conditions of the coating film itself in real time. It is also possible to improve the quality of the coating film. On the other hand, in the method described in Patent Document 1 and Patent Document 2, in which the amount of coating liquid applied is changed by measuring the film thickness or film thickness distribution before drying, the film thickness or film thickness distribution is If the above conditions are not met, the measured part will be considered defective and will be discarded. In contrast, in the present embodiment, even when the solvent vapor deviates from the predetermined conditions, the conditions of the step of drying the coating liquid (step S120) are changed, and the coating film obtained from the measurement site is It is possible to achieve the desired film thickness or reduce film thickness unevenness.

These controls can be performed by each component under the control of the control unit 360. Alternatively, the control unit 360 may issue a warning such as an alarm depending on the observed state of the solvent vapor, and manually change each manufacturing condition based on the warning.

1-4. Step of forming a coating film (step S140)
In this step, the coating liquid is applied in the previous steps, and after drying, a coating film is formed. Note that, depending on the type of coating film, if the desired coating film is formed up to the previous step, this step is not necessary.

For example, when forming the above-described undercoat layer 120, charge generation layer 130, and charge transport layer 140, the coating film may be heated as necessary to volatilize the residual solvent. Further, when forming the above-mentioned overcoat layer 150, the coating film may be heated or irradiated with actinic rays such as ultraviolet rays to polymerize the polyfunctional radically polymerizable compound and cure the coating film. These processing conditions may be the usual conditions used when forming these layers.

Further, a known finishing treatment may be performed depending on the type of coating film to be formed.

In this embodiment, the above steps are repeated for the undercoat layer 120, charge generation layer 130, charge transport layer 140, and overcoat layer 150 to form the electrophotographic photoreceptor 100 having these layers. Note that each of the above steps may be performed when forming all layers, or may be performed only when forming one or more specific layers. This embodiment has a remarkable effect of reducing film thickness unevenness when forming a thick layer, and is preferably carried out, for example, when forming a thick charge transport layer 140.

2. Electrophotographic Photoreceptor and Image Forming Apparatus The photoreceptor 100 manufactured by performing the above steps can be used as a photoreceptor in a known electrophotographic image forming apparatus.

FIG. 6 is a schematic diagram showing an exemplary configuration of an image forming apparatus having the photoreceptor 100. As shown in FIG. 6, the image forming apparatus 1 includes an image reading section 10, an operation display section 20, an image processing section 30, an image forming section 40, a paper transport section 50, a fixing section 60, and a control section 70.

The control unit 70 is a device for centrally controlling the operation of each block of the image forming apparatus 1 in cooperation with a developed program, and includes, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), and a RAM ( Random Access Memory).

The image reading unit 10 includes an automatic document feeder 11 called an ADF (Auto Document Feeder), a document image scanning device 12 (scanner), and the like. The operation display section 20 is configured with, for example, a liquid crystal display (LCD) with a touch panel, and functions as a display section and an operation section. The image processing unit 30 includes a circuit that performs digital image processing on input image data according to initial settings or user settings.

The image forming unit 40 includes an image forming unit 41, an intermediate transfer unit 42, and a secondary transfer unit for forming images using colored toners of Y component, M component, C component, and K component based on input image data. 43 etc.

The image forming unit 41 includes four image forming units 41Y, 41M, 41C, and 41K for Y component, M component, C component, and K component. Image forming units 41Y, 41M, 41C, and 41K have similar configurations, so for convenience of illustration and explanation, common components are indicated by the same reference numerals, and when distinguishing between them, the reference numerals Y, M, and C are used. , or K. In FIG. 1, only the constituent elements of the image forming unit 41Y for the Y component are labeled, and the constituent elements of the other image forming units 41M, 41C, and 41K are omitted.

The image forming unit 41 includes an exposure device 411, a developing device 412, a photoreceptor 100, a charging device 414, a drum cleaning device 415, and the like.

The photoreceptor 100 is an electrophotographic photoreceptor manufactured through the above steps, and includes a conductive substrate 110, an undercoat layer (UCL) 120, a charge generation layer (CGL) 130, and a charge transport layer, which are laminated in this order. It is a negatively charged organic photo-conductor (OPC) having a layer (CTL) 140 and an overcoat layer (OCL) 150.

The charging device 414 is a non-contact charging device that uses corona discharge, for example. The charging device 414 may be a contact type charging device that charges the photoreceptor 100 by contacting it. The exposure device 411 is composed of, for example, a semiconductor laser. The developing device 412 is a developing device for a two-component developer, and stores developer of each color component (for example, a two-component developer consisting of a small particle size toner and a magnetic material). The drum cleaning device 415 has a drum cleaning blade, such as an elastic blade, that is arranged to be able to slide on the surface of the photoreceptor 100.

The intermediate transfer unit 42 includes an intermediate transfer belt 421, a primary transfer roller 422, a plurality of support rollers 423 including a backup roller 423A, a belt cleaning device 426, and the like.

The intermediate transfer belt 421 is an endless belt, and is stretched around a plurality of support rollers 423 in a loop shape. At least one of the plurality of support rollers 423 is a driving roller, and the others are driven rollers. The belt cleaning device 426 has a belt cleaning blade, such as an elastic blade, that is arranged to be able to slide on the surface of the intermediate transfer belt 421.

The secondary transfer unit 43 includes, for example, a secondary transfer roller 431. The secondary transfer unit 43 may have a configuration in which a secondary transfer belt is stretched around a plurality of support rollers including a secondary transfer roller in a loop shape.

The fixing section 60 is arranged within the fixing device F as a unit. The fixing unit 60 includes an endless fixing belt 61, two rollers 64 and 65 for endlessly supporting the fixing belt 61, and a roller for heating the fixing belt 61 supported by the rollers 64 and 65. It has a heating device 63 and a pressure roller 62 arranged so as to be biased relative to a roller 64.

The roller 64 is arranged to face the pressure roller 62 via the fixing belt 61, and has a diameter of 50 mm or more. The rollers 64 and 65 support the fixing belt 61 on an endless track with a tension of 45N. For example, roller 64 is a driving roller and roller 65 is a driven roller. The heating device 63 is composed of, for example, a halogen lamp or a resistance heating element, and is built into the roller 65. The pressure roller 62 is arranged to be able to approach and leave the roller 64 freely. When the pressure roller 62 comes into pressure contact with the fixing belt 61 supported by the roller 64, a fixing nip portion is formed in which the sheet S is held and conveyed. The paper S corresponds to a recording medium, and is, for example, standard paper or special paper.

Note that the heating device 63 may be an electromagnetic induction heating (IH) type heating device. Further, an air separation unit may be further disposed within the fixing device F to separate the paper S from the fixing belt 61 or the pressure roller 62 by blowing air. The fixing unit 60 corresponds to the fixing device described above.

The paper transport section 50 includes a paper feed section 51, a paper discharge section 52, a first transport section 53, a second transport section 57, and the like. The three paper feed tray units 51a to 51c constituting the paper feed section 51 accommodate sheets S identified based on basis weight, size, etc., according to preset types. The first conveyance section 53 includes a plurality of conveyance roller sections including an intermediate conveyance roller section 54, a loop roller section 55, and a registration roller section 56. The second conveyance section 57 includes a switchback path 58 and a back surface conveyance path 59 in which a plurality of conveyance roller sections are arranged.

In the image forming apparatus 1 , an automatic document feeder 11 uses a conveyance mechanism to convey a document D placed on a document tray and sends it to a document image scanning device 12 . The automatic document feeder 11 can continuously read images (including both sides) of a large number of documents D placed on a document tray at one time. The document image scanning device 12 optically scans the document conveyed onto the contact glass from the automatic document feeder 11 or the document placed on the contact glass, and converts the reflected light from the document into a CCD (Charge Coupled Device). ) An image is formed on the light receiving surface of the sensor 12a and the original image is read. The image reading unit 10 generates input image data based on the reading result by the original image scanning device 12. This input image data is subjected to predetermined image processing in the image processing section 30 as necessary.

The control unit 70 controls a drive current supplied to a drive motor (not shown) that rotates the photoreceptor 100. Thereby, the photoreceptor 100 rotates at a constant peripheral speed. The charging device 414 uniformly charges the surface of the photoreceptor 100 having photoconductivity to a negative polarity. The exposure device 411 irradiates the photoreceptor 100 with laser light corresponding to an image of each color component, and an electrostatic latent image of each color component is formed on the surface of the photoreceptor 100 due to a potential difference with the surroundings. The developing device 412 makes the electrostatic latent image visible by depositing toner of each color component on the surface of the photoreceptor 100 to form a toner image.

On the other hand, the intermediate transfer belt 421 runs at a constant speed in the direction of arrow A as a support roller 423 serving as a drive roller rotates. By pressing the intermediate transfer belt 421 against the photoconductor 100 by the primary transfer roller 422, a primary transfer nip is formed, and the toner images of each color on the photoconductor 100 are sequentially overlapped on the intermediate transfer belt 421. The primary transfer is as follows. Transfer residual toner remaining on the surface of the photoreceptor 100 is removed from the surface after the primary transfer by the elastic blade in contact with the surface of the photoreceptor 100 in the drum cleaning device 415.

On the other hand, the secondary transfer roller 431 is pressed against the backup roller 423A via the intermediate transfer belt 421, thereby forming a secondary transfer nip portion. The paper S fed from the paper feed section 51 or the second conveyance section 57 is conveyed to the secondary nip transfer section. The inclination and widthwise position (shift) of the sheet S are corrected during the process of being transported by the first transporting section 53.

When the paper S passes through the secondary transfer nip portion, the toner image carried on the intermediate transfer belt 421 is secondarily transferred to the paper S. The paper S onto which the toner image has been transferred is conveyed toward the fixing section 60. Transfer residual toner remaining on the surface of the intermediate transfer belt 421 after the secondary transfer is removed from the surface by the elastic blade in contact with the surface of the intermediate transfer belt 421 in the belt cleaning device 426.

The fixing unit 60 fixes the toner image on the paper S by heating and pressurizing the transported paper S with a fixing nip. Drive control of the fixing belt 61, pressure roller 62, heating device 63, etc. is performed by a control unit 70.

The fixing belt 61 is heated by the heating device 63, and as a result, the fixing belt 61 becomes uniform at a predetermined fixing temperature (for example, 170° C.) across the width. The fixing temperature is a temperature that can supply the thermal energy necessary to melt the toner on the paper S, and varies depending on the type of paper S on which an image is formed.

In the case of double-sided printing, the second conveyance unit 57 once conveys the paper S to the switchback path 58, then switches back and conveys it to the back side conveyance path 59, thereby reversing the sheet S and printing the paper S to the first side. It is supplied to the conveying section 53 (upstream of the loop roller section 55). Then, the paper S is supplied to the secondary transfer nip section again to transfer the desired toner image onto the paper S, and then the toner image is fixed onto the paper S in the fixing section 60.

The sheet S on which the desired image has been formed in this manner is discharged to the outside of the image forming apparatus 1 by a sheet discharge section 52 equipped with a sheet discharge roller 52a.

Note that the present invention is not limited to the above-described embodiments, and it goes without saying that various modifications can be made within the scope of the idea of the present invention.

For example, in the above-described embodiment, the present invention has been explained by taking as an example the manufacture of each layer constituting an electrophotographic photoreceptor, but as long as a coating liquid containing an organic solvent is applied to a substrate, the organic solvent is evaporated, and the substrate is dried. The present invention can be applied to the production of various surface treatment layers. Furthermore, the membranes to be manufactured are not limited to resin membranes, and the present invention can be applied to the manufacture of various organic and inorganic membranes.

According to the present invention, there is provided a method for producing a coating film that can suppress nonuniformity in film thickness caused not only by coating conditions but also by environmental conditions after coating and during drying.

1 Image forming device 10 Image reading section 11 Automatic document feeder 12 Document image scanning device 12a CCD sensor 20 Operation display section 30 Image processing section 40 Image forming section 41 Image forming unit 42 Intermediate transfer unit 43 Secondary transfer unit 50 Paper transport Section 51 Paper feed section 51a to 51c Paper feed tray unit 52 Paper discharge section 52a Paper discharge roller 53 First conveyance section 54 Intermediate conveyance roller section 55 Loop roller section 56 Registration roller section 57 Second conveyance section 58 Switchback path 59 Conveyance path for back surface 60 Fixing section 61 Fixing belt 62 Pressure roller 63 Heating device 64, 65 Roller 70 Control section 100 Photoreceptor 110 Conductive substrate 120 Undercoat layer 130 Charge generation layer 140 Charge transport layer 150 Overcoat layer 300 Coating film Manufacturing apparatus 310 Applying section 312 Coating liquid tank 313 Stirring section 314 Coating liquid tank 315 Diluting solvent tank 315a Diluting solvent pump 316 Coating liquid receiving tank 318 Coating liquid pump 320 Drying section 322 Covering body 322a, 322b Discharge port 330 Monitor section 332 Infrared rays Camera 340 Substrate transport section 350 Air conditioning section 360 Control section 370 Substrate 411 Exposure device 412 Developing device 414 Charging device 415 Drum cleaning device 421 Intermediate transfer belt 422 Primary transfer roller 423 Support roller 423A Backup roller 426 Belt cleaning device 431 Secondary transfer roller D Original F Fuser

Claims (12)

a step of applying a coating liquid containing an organic solvent to a substrate;
A method for producing a coating film, comprising the step of drying the applied coating liquid,
a step of changing manufacturing conditions according to the state of solvent vapor generated by volatilization of the organic solvent observed in the drying step;
Method of manufacturing a coating film. The method for manufacturing a coating film according to claim 1, wherein in the changing step, the manufacturing conditions are changed so as to reduce unevenness in the thickness of the coating film. In the applying step, immersing the substrate in the coating liquid,
In the changing step, changing the immersion conditions of the substrate in the coating liquid,
A method for producing a coating film according to claim 1 or 2. 4. The method for producing a coating film according to claim 3, wherein in the changing step, the stirring time or stirring intensity of the coating liquid in which the substrate is immersed is changed. The drying step is performed inside a covering covering the substrate,
In the changing step, changing the drying conditions of the coating liquid inside the coating,
A method for producing a coating film according to claim 1 or 2. The method for producing a coating film according to claim 5, wherein in the changing step, the residence time of the substrate inside the coating is changed. The method for producing a coating film according to claim 1 or 2, wherein the drying step is performed while moving the substrate in a vertical direction. The method for producing a coating film according to claim 1 or 2, wherein in the drying step, the absorption wavelength band of the solvent vapor is monitored using an infrared camera. A method for manufacturing an electrophotographic photoreceptor, which comprises performing the method for manufacturing a coating film according to claim 1 or 2. an application part that applies a coating liquid containing an organic solvent to a substrate;
a drying section that dries the applied coating liquid;
a monitor unit that monitors vapor produced by volatilization of the applied coating liquid;
a control unit that changes manufacturing conditions according to the monitored state of the steam;
Paint film manufacturing equipment. An electrophotographic photoreceptor comprising a coating film produced by the coating film production method according to claim 1 or a coating film produced using the coating film production apparatus according to claim 10. An image forming apparatus comprising the electrophotographic photoreceptor according to claim 11.

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