JP6801545B2 - Manufacturing method of electrophotographic photosensitive member - Google Patents

Description

The present invention relates to a method for producing an electrophotographic photosensitive member. More specifically, the present invention enables uniform film formation by suppressing variations in film thickness among a plurality of coaters, and enables stable coating over a long period of time. The present invention relates to a method for producing an electrophotographic photosensitive member.

The slide hopper coating method (see, for example, Patent Document 1) is a coating method in which the amount of the supplied liquid is coated and formed on the object to be coated, unlike the immersion coating method, and is used for film thickness control. It is important to control the amount of liquid supplied. Therefore, it is ideal to prepare one liquid supply pump for one coater, but a large cost is required for the equipment. In addition, there are considerable restrictions on the selection of a liquid supply pump that can suppress pulsation (beat) and stably supply a coating liquid in a small-diameter type drum or a small amount of liquid feeding for thin film formation. Furthermore, the installation of a small amount flow meter for liquid is not commercially available as a general-purpose product, is extremely expensive, and its management is extremely difficult due to the application of an organic solvent.

For this reason, it is conceivable to supply liquid to multiple coaters with one liquid supply pump to increase the amount of liquid, but in this case, the balance of the amount of supplied liquid is lost due to pressure loss, clogging of the coater, etc., and each coater There is a problem that a desired film thickness cannot be obtained due to a situation where coating films having different film thicknesses occur.

Japanese Unexamined Patent Publication No. 2013-257504

The present invention has been made in view of the above problems and situations, and the solution to the problem is to suppress variations in film thickness among a plurality of coaters, enable uniform film formation, and stabilize for a long period of time. It is an object of the present invention to provide a method for producing an electrophotographic photosensitive member which can be applied.

In order to solve the above problems, the present inventor connects the liquid supply pipes that supply the coating liquid from the liquid supply pump to a plurality of coaters via the connecting pipes in the process of examining the cause of the above problems. By encapsulating the coating liquid and gas in the pipe and making the liquid level in the connecting pipe higher than the position of the coating liquid discharge port of the coater to form a film, the film thickness varies among a plurality of coaters. We have found that it is possible to provide a method for producing an electrophotographic photosensitive member that suppresses and enables uniform film formation and enables stable coating over a long period of time, and has reached the present invention.

That is, the above problem according to the present invention is solved by the following means.

1. A method for manufacturing an electrophotographic photosensitive member using a slide hopper coating device that supplies coating liquid from one liquid supply pump to a plurality of coaters.
The liquid supply pipes that supply the coating liquid from the liquid supply pump to the plurality of coaters are connected via a connecting pipe, the coating liquid and the gas are sealed in the connecting pipe, and the liquid level in the connecting pipe is filled. A method for producing an electrophotographic photosensitive member, which comprises forming a film with a height higher than the position of a coating liquid discharge port of the coater.

2. 2. The inner diameters of the liquid supply pipes are all the same.
The inner diameter of the connecting pipe is made larger than the inner diameter of the liquid supply pipe, and
The method for producing an electrophotographic photosensitive member according to item 1, wherein the height of the liquid level in the connecting tube is raised by 1 m or more from the position of the coating liquid discharge port.

3. 3. The method for producing an electrophotographic photosensitive member according to item 2, wherein the inner diameter of the connecting tube is 1.2 times or more the inner diameter of the liquid supply tube.

4. The method for producing an electrophotographic photosensitive member according to any one of items 1 to 3, which satisfies the following relational expressions (1) and (2).

Q = w × πD × v… (1)
w <K × {(η ・ v) / (ρ ・ g)} ¹ / ² … (2)

(Here, Q: the flow rate of the coating liquid, w: the wet film thickness, D: the outer diameter of the object to be coated, v: the transport speed of the object to be coated, K: the coating film setting speed and the amount of sagging. It is a coefficient to be determined, K = 0.7, η: coating liquid viscosity, ρ: coating liquid density, g: gravitational acceleration.)

The above means of the present invention provides a method for producing an electrophotographic photosensitive member, which suppresses film thickness variation among a plurality of coaters, enables uniform film formation, and enables stable coating over a long period of time. be able to.

Although the mechanism of expression and mechanism of action of the effects of the present invention have not been clarified, it is inferred as follows.

In the case of an electrophotographic photosensitive member, for example, in forming a film of a surface layer, it is necessary to uniformly form a thin coating film of several μm. Further, in the photoconductor of a small-diameter drum (for example, an outer diameter of φ30 mm or less), the coating film volume is extremely small. Since a certain amount of liquid viscosity is required for uniform film formation, it is necessary to maintain the solid content concentration to some extent.

Specifically, for example, in order to form a coating film of 3 μm using a coating liquid having a solid content concentration of 10.0% by volume, the wet film thickness is 30 μm, and this is applied to a work piece having a diameter of 30 mm. When the transport speed of the object to be coated is v = 15 mm / sec, the supply liquid amount Q is
Q = 3π × 0.003 × 1.5 (cm ³ / sec)
= 0.0424 (cm ³ / sec)
= 2.54 (cm ³ / min)
Will be.

In order to stably supply such a very small amount of liquid without pulsation, one pump should send the liquid to multiple coaters at once and increase the amount of liquid to be supplied to stabilize the pulsation. Can be done. At this time, when distributing the coating liquid to a plurality of coaters, the liquid amount must be uniformly distributed.
By the way, due to the configuration of the coater, it is required to make the slit gap (gap at the outlet of the coating liquid) equal to or several times the wet film thickness. For example, in the above example, the wet film thickness is assumed to be 30 μm, but in this case, the slit gap needs to be about 50 to 80 μm.
Since there is only a small gap in this way, if any one coater is slightly clogged during coating, pressure loss will occur and the balance of the amount of coating liquid supplied to multiple coaters will be lost, making it uniform. It will not be possible to distribute. In such a case, as described above, the amount of the supplied liquid itself is directly linked to the film thickness, so that the film thickness becomes non-uniform among the coaters.

Therefore, in the present invention, the liquid supply pipes that supply the coating liquid from the liquid supply pump to the plurality of coaters are connected via the connecting pipe, and the coating liquid and the gas are sealed in the connecting pipe and the liquid in the connecting pipe is sealed. The surface height is set higher than the position of the coating liquid discharge port of the coater to form a film.
By making the liquid level height in the connecting pipe higher than the position of the coating liquid discharge port of the coater, the flow rate is stabilized by the force of its own weight from the coating liquid discharge port of the coater to the liquid level in the connecting pipe. The force that maintains the liquid level in the connecting pipe works even if there is a fluctuation in the flow rate, and the force that keeps the flow rate constant works by suppressing the variation in film thickness between multiple coaters, resulting in uniform film formation. It is considered possible.
In addition, even if the amount of liquid supplied between the coaters fluctuates due to slight drying due to continuous coating, the liquid level tends to be constant and the flow rate becomes uniform among the coaters. Since it works, it is considered that stable application is possible for a long period of time while clearing the clogging with the head pressure at an early stage.

Schematic diagram showing a method of forming a coating film on an object to be coated using the slide hopper coating apparatus according to the present invention. Sectional drawing which shows the schematic structure as an example of the coater which concerns on this invention. Graph showing the relationship between η ・ v and w (A) is a side view of the electrophotographic photosensitive member according to the present invention, and (b) is an enlarged cross-sectional view of the C portion of (a). Partially enlarged cross-sectional view showing another aspect of the electrophotographic photosensitive member according to the present invention. Schematic diagram showing a schematic configuration as an example of an image forming apparatus

The method for producing an electrophotographic photosensitive member of the present invention is a method for producing an electrophotographic photosensitive member using a slide hopper coating device that supplies a coating liquid from one liquid supply pump to a plurality of coaters. The liquid supply pipes that supply the coating liquid to a plurality of coaters are connected via the connecting pipe, the coating liquid and the gas are sealed in the connecting pipe, and the liquid level height in the connecting pipe is adjusted to the coating liquid discharge port of the coater. It is characterized in that the film is formed higher than the position of. This feature is a technical feature common to the inventions according to each claim.

In an embodiment of the present invention, from the viewpoint of suppressing pulsation and stabilizing the pressure balance, the inner diameters of the liquid supply pipes are all the same, the inner diameter of the connecting pipe is made larger than the inner diameter of the liquid supply pipe, and the inside of the connecting pipe is formed. The liquid level height is preferably 1 m or more higher than the position of the coating liquid discharge port, and more preferably the inner diameter of the connecting pipe is 1.2 times or more the inner diameter of the liquid supply pipe.

Further, from the viewpoint of applying and fixing all the supplied coating liquid to the object to be coated, it is preferable to satisfy the relational expressions (1) and (2).

Hereinafter, the present invention, its constituent elements, and modes and modes for carrying out the present invention will be described in detail. In the present application, "~" indicating a numerical range is used to mean that the numerical values described before and after the numerical range are included as the lower limit value and the upper limit value.

<< Manufacturing method of electrophotographic photosensitive member >>
The method for producing an electrophotographic photosensitive member of the present invention is a method for producing an electrophotographic photosensitive member using a slide hopper coating device that supplies a coating liquid from one liquid supply pump to a plurality of coaters. The liquid supply pipes that supply the coating liquid to a plurality of coaters are connected via the connecting pipe, the coating liquid and the gas are sealed in the connecting pipe, and the liquid level height in the connecting pipe is adjusted to the coating liquid discharge port of the coater. It is characterized in that the film is formed higher than the position of.

Hereinafter, the method for producing the electrophotographic photosensitive member of the present invention will be described with reference to the drawings.
In the following, a circular slide hopper coating device having a cylindrical coater will be described as the slide hopper coating device, but the present invention is not particularly limited to this, and for example, a slide hopper coating device having a flat coater is used. You may. Further, for the sake of simplification of the description, the case of having two coaters will be described, but the description is not limited thereto.

<Circular slide hopper coating device>
As shown in FIG. 1, the circular slide hopper coating device 100 is provided so as to surround the storage tank 110 for storing the coating liquid, the liquid supply pump 120 for supplying the coating liquid CL, and the cylindrical base material 140. It is configured to include an annular coater 130.
A shunt 122 for dividing the coating liquid is provided between the liquid supply pump 120 and each coater 130, and the shunt 122 and each coater 130 are connected via the liquid supply pipes 123 and 124. It is preferable that the inner diameters of the liquid supply pipes 123 and 124 are the same. Here, the fact that the inner diameters of the liquid supply pipes are all the same means that the inner diameters of the plurality of liquid supply pipes are within ± 1%.
The liquid supply pipes 123 and 124 are connected by one connecting pipe 125. The inner diameter of the connecting pipe 125 is preferably larger than the inner diameter of the liquid supply pipes 123 and 124 from the viewpoint of increasing the force of the own weight of the coating liquid from the coating liquid discharge port 131 of the coater 130 to the liquid surface in the connecting pipe 125. , It is more preferable that the inner diameter of the liquid supply pipes 123 and 124 is 1.2 times or more. The upper limit is not particularly limited, but is preferably 10 times or less the inner diameter of the liquid supply pipes 123 and 124 due to restrictions on the installation of the connecting pipe 125.

Here, the base material 140 is a base material to which the coating liquid for forming each layer of the electrophotographic photosensitive member is to be applied. For example, a conductive substrate or a charge generation layer is formed on the conductive substrate. Examples thereof include those in which a charge generation layer and a charge transport layer are formed on a conductive substrate, and FIG. 1 shows a case where the substrate 140 is a conductive substrate.

As shown in FIG. 2, the coater 130 has a narrow coating liquid distribution slit 132 having a coating liquid discharge port 131 opening on the substrate 140 side along a direction perpendicular to the longitudinal direction of the substrate 140. , Is formed over the entire circumference of the annular coater 130. The coating liquid distribution slit 132 communicates with the annular coating liquid distribution chamber 133, and in the coating liquid distribution chamber 133, the coating liquid CL in the storage tank 110 is passed through the liquid supply pipes 123 and 124 by the liquid supply pump 120. Is formed to be supplied.
A slide surface 134 that is continuously inclined downward is formed in the lower portion of the coating liquid discharge port 131 of the coating liquid distribution slit 132.
A pipe 135 for bleeding air is provided in the upper part of the coating liquid distribution chamber 133.

<Circular slide hopper application method>
Next, a method for manufacturing an electrophotographic photosensitive member by a circular slide hopper coating method using the circular slide hopper coating device 100 described above will be described.
First, the valves 126 and 136 provided on the upper part of the connecting pipe 125 and the upper part of the coater 130 are opened, and in this state, the coating liquid CL in the storage tank 110 is sent into the circular slide hopper coating device 100. More specifically, the coating liquid CL is sent from the storage tank 110 to the liquid supply pump 120 via the pipe 111. First, the coating liquid CL is pressure-fed to the shunt 122 by the liquid supply pump 120 via the pipe 121. After that, the coating liquid CL pumped to the shunt 122 is evenly distributed by the shunt 122 and pumped to the supply pipes 123, 124, the connecting pipe 125, and the coater 130.
The height of the liquid level in the connecting pipe 125 is adjusted to be higher than the height of the coating liquid discharge port 131 of the coater 130, and then the valves 126 and 136 are closed. At this time, the upper part of the connecting pipe 125 is in a state where gas remains (a corresponding liquid level exists for each coater 130).
The height of the liquid level in the connecting pipe 125 is preferably 1 m or more higher than the height of the position of the coating liquid discharge port 131. If it is 1 m or more, the effect of the head pressure at the coating liquid discharge port 131 is large, and the pressure balance is not easily lost. The upper limit is not particularly limited, but is preferably 10 m or less in practice from the viewpoint of the liquid feeding capacity of the liquid supply pump 120 and the scale of the coating device 100.
The gas sealed in the upper part of the connecting pipe 125 is not particularly limited, and examples thereof include air and an inert gas.
The coater 130 to the valve 136 are in a state where the coating liquid CL is filled. Further, from the viewpoint of effectively bleeding air, the coating liquid distribution slit 132 may be provided so as to be inclined toward the valve 136.

In this state, the base material 140 is moved in the arrow direction X by the air bearing 150 while supplying the coating liquid CL to each coater 130. The coating liquid CL extruded from the coating liquid discharge port 131 flows down along the slide surface 134. The coating liquid CL that reaches the tip of the slide surface 134 forms a coating liquid pool called a bead between the slide surface 134 and the base material 140, and high-precision coating is performed on the base material 140 through the bead. The coating film F is formed.

According to the above, since the force of the coating liquid CL's own weight from the height of the position of the coating liquid discharge port 131 of the coater to the liquid surface in the connecting pipe 125 is large, the flow rate fluctuates due to slight drying due to continuous coating. Even if there is, a force to maintain the liquid level in the connecting pipe 125 connected to each of the liquid supply pipes 123 and 124 works, and a force to keep the flow rate constant by the force works between the plurality of coaters 130. It is possible to suppress the variation in film thickness and enable uniform film formation, and to enable stable coating over a long period of time.

When the liquid level in the connecting pipe 125 is below the height of the position of the coating liquid discharge port 131 of the coater 130, when there is a difference in the flow rate, it is observed as a differential pressure ΔP. Therefore, if these two piping systems (a connecting pipe 125 whose liquid level is higher than the height of the position of the coating liquid discharge port 131 and a connecting pipe whose liquid level is lower) are used together, if there is a difference in the flow rate change, ΔP It is possible to confirm the effect of the high-lift piping from the change of.

In the coating method using such a circular slide hopper coating device 200, the tip of the slide surface 134 and the base material 140 are arranged with a certain gap (for example, about 20 μm to 2 mm), so that the base material 140 is used. It can be applied without damaging the already applied layer without damaging the layer having different properties.
Furthermore, even when multiple layers that have different properties and are soluble in the same solvent are formed, the time of contact with the solvent is much shorter than that of the dip coating method, so that the lower layer components hardly elute to the upper layer side, and during dip coating. Since it can be applied to the coating tank without elution, for example, it can be applied without deteriorating the dispersibility of the metal oxide fine particles.

Further, in the circular slide hopper coating method, it is preferable to satisfy the following relational expressions (1) and (2).

Q = w × πD × v… (1)
w <K × {(η ・ v) / (ρ ・ g)} ¹ / ² … (2)

Here, Q: the flow rate of the coating liquid, w: the wet film thickness, D: the outer diameter of the object to be coated, v: the transport speed of the object to be coated, K: the coating film setting speed and the amount of sagging. K = 0.7, η: coating liquid viscosity, ρ: coating liquid density, g: gravitational acceleration.

Hereinafter, description will be made with reference to the drawings.
FIG. 3 is a graph showing the relationship between η · v and the wet film thickness w.
In FIG. 3, the uppermost line L1 corresponds to the dipping (immersion) region and corresponds to K = 1.0. In this region, it does not become a slide hopper coating region, and it is not necessary to control the flow rate because the flow rate is excessive, but in reality, the state of K = 1.0 due to the competition between the coating film setting speed and the amount of sagging. Is difficult to obtain.
The bottom line L4 is the limit of the supply liquid amount, and is an empirical line in which the supply liquid amount is too small and the coating liquid runs out.
The second line L3 from the bottom is a sharp region line where the coating liquid is theoretically cut off. When the viscosity of the coating liquid is low, the coating liquid flows without breaking, but when the viscosity is high, the coating liquid does not easily flow and runs out. That is, in creating the theoretical sharp region line, the value of K differs depending on whether the value is on the low viscosity side (K = 0.025) or on the high viscosity side (K = 0.225). Therefore, for safety reasons, the line is defined by K = 0.225 on the high viscosity side so that the coating film can be applied with either low viscosity or high viscosity.

That is, if the value of K is specified so that the line is defined in the region sandwiched between the line L1 and the line L3, stable coating film formation can be realized, but in the present invention, it is possible to realize a stable coating film formation. It is preferable that K = 0.7 (line L2). This K = 0.7 means that the solvent evaporates and the coating film is fixed, and the amount of the coating liquid dripping due to gravity (the amount of sagging) before the coating film is fixed is balanced, that is, It defines the area where the supplied coating liquid is all applied and fixed to the base material to be coated.

<< Electrophotographic photosensitive member >>
As shown in FIGS. 4A and 4B, the electrophotographic photosensitive member 10 according to the present invention is formed on a drum-shaped (cylindrical) long conductive substrate 1 and the conductive substrate 1. It has a photosensitive layer 2 and the like. The photosensitive layer 2 may be composed of a charge generating layer 2a and a charge transporting layer 2b, or may be configured as a single layer containing a charge generating substance and a charge transporting substance, but the charge generating layer 2a and the charge transporting material may be formed. It is preferable to have a two-layer structure of the layer 2b.

Further, as shown in FIG. 5, the electrophotographic photosensitive member 10 of the present invention may have an undercoat layer 3, a surface protective layer 4, and the like, which will be described later. The surface protective layer 5 contains the metal oxide fine particles 5.

<Conductive substrate>
The conductive substrate is drum-shaped (cylindrical) and has cavities at both ends in the axial direction. Inro-processed portions may be formed on the inner peripheral surfaces of both ends in the axial direction of the conductive substrate. The in-row processing portion is a portion to which the flange is fitted when the flange is attached to the electrophotographic photosensitive member.

The outer diameter of the conductive substrate is preferably in the range of 20 to 120 mm, preferably in the range of 24 to 100 mm. The outer diameter of the conductive substrate is preferably 24 mm or more from a practical point of view.

The average wall thickness of the portion of the conductive substrate excluding the in-row processed portion is preferably 2 mm or less, and more preferably 1.5 mm or less. Further, if the outer diameter is φ60 mm or less, 1.0 mm or less is more preferable.

When the in-row processed portion is provided, the diameter of the in-row processed portion is preferably in the range of the outer diameter after surface cutting of −1.4 to the outer diameter after surface cutting of -2.2 mm.
Further, it is preferable that the distance from the in-row processed portion of the conductive substrate to the chamfering start point position is appropriately set within a range that matches the relationship between the outer chamfering amount and the above-mentioned in-row diameter. The preferable range differs depending on the outer diameter of the conductive substrate. For example, when the outer diameter is φ30 mm, it is preferably within the range of 0.70 to 0.74 mm.

The runout accuracy (dimensional accuracy) of the conductive substrate is preferably 0.05 mm or less, and more preferably 0.03 mm or less.

The axial length of the conductive substrate is preferably in the range of 220 to 500 mm.

The surface roughness Rt of the conductive substrate is preferably 0.6 μm or more, and more preferably in the range of 0.8 to 1.4 μm. "Surface roughness Rt" is a parameter conforming to JIS B 0601: 2001, and is the maximum cross-sectional height of the roughness curve according to the JIS standard.

As the material of the conductive substrate (original pipe), various materials can be used, but in general, aluminum or an aluminum alloy is used from the viewpoint of electric conductivity, processability and manufacturing cost, and among them, among them, JIS A 1000 series, 3000 series (Al-Mn alloy), 5000 series (Al-Mg alloy) or 6000 series (Al-Mg-Si alloy) are preferable.

<Photosensitive layer>
As described above, the photosensitive layer preferably has a layer structure in which the functions of the photosensitive layer (charge generation function and charge transport function) are separated into a charge generation layer and a charge transport layer. According to the function-separated layer structure, the increase in the residual potential due to repeated use can be controlled to be small, and various electrophotographic characteristics can be easily controlled according to the purpose.
The negatively charged photoconductor has a configuration in which a charge generation layer is provided on the undercoat layer and a charge transport layer is provided on the charge generation layer. The positively charged photoconductor has a configuration in which a charge transport layer is provided on the undercoat layer and a charge generation layer is provided on the charge transport layer.
A preferred embodiment of the photosensitive layer is a negatively charged photosensitive member having a function-separated structure.
Here, as a specific example of the photosensitive layer, each layer of the photosensitive layer of the function-separated negatively charged photosensitive member will be described.

(Charge generation layer)
The charge generating layer contains a charge generating substance (CGM).
Charge generators include azo raw materials such as Sudan Red and Diane Blue, quinone pigments such as pyrenequinone and antoanthron, quinosianin pigments, perylene pigments, indigo pigments such as indigo and thioindigo, hydroxygallium phthalocyanine, chlorogallium phthalocyanine and titanyl phthalocyanine. Phthalocyanine pigments and the like can be mentioned. Among these, phthalocyanine pigments having a sensitivity of 700 nm or more are preferable, and among them, titanyl phthalocyanine pigments, particularly Y-titanyl phthalocyanine (Cu-Kα characteristic X-ray diffraction spectrum measurement, the maximum diffraction peak is at least 27.3 °. It is a titanyl phthalocyanine pigment having a very large absorption at 780 nm. It is described as Y-TiOPc), but the charge generating substance is not limited thereto.

These charge generating substances can be used alone or in a form of being dispersed in a known binder resin.

A known resin can be used as the binder resin for forming the charge generation layer, for example, polystyrene resin, polyethylene resin, polypropylene resin, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, polyvinyl butyral resin, epoxy. Resins, polyurethane resins, phenolic resins, polyester resins, alkyd resins, polycarbonate resins, silicone resins, melamine resins, and copolymer resins containing two or more of these resins (eg, vinyl chloride-vinyl acetate copolymer resins). , Vinyl chloride-vinyl acetate-maleic anhydride copolymer resin), polyvinyl carbazole resin and the like, but the present invention is not limited thereto.

When forming a charge generating layer, a coating liquid is prepared by dispersing the charge generating substance in a solution in which a binder resin is dissolved in a solvent using a disperser, and the coating liquid is spread on a conductive substrate to a constant layer thickness. It can be formed by applying to form a coating film and drying the coating film.

Known methods for applying the coating liquid for forming a charge generation layer include, for example, a dip coating method, a spray coating method, a spinner coating method, a bead coating method, a blade coating method, a beam coating method, a slide hopper method, and a circular slide hopper method. In particular, in the present invention, the circular slide hopper method using a circular slide hopper coating device is preferable.

The method for drying the coating film can be appropriately selected depending on the type of solvent and the layer thickness, but heat drying is preferable.

Examples of the solvent for dissolving and applying the binder resin used for the charge generation layer include toluene, xylene, methyl ethyl ketone, cyclohexane, ethyl acetate, butyl acetate, methanol, ethanol, propanol, butanol, methyl cellosolve, ethyl cellosolve, and tetrahydrofuran. , 1,4-dioxane, 1,3-dioxolane, pyridine, diethylamine and the like, but are not limited thereto.

As the means for dispersing the charge generating substance, an ultrasonic disperser, a ball mill, a sand grinder, a homomixer and the like can be used, but the method is not limited thereto.

The mixing ratio of the charge generating substance with respect to the binder resin is preferably in the range of 1 to 600 parts by mass, and more preferably in the range of 50 to 500 parts by mass with respect to 100 parts by mass of the binder resin.

The thickness of the charge generating layer varies depending on the characteristics of the charge generating substance, the characteristics of the binder resin, the mixing ratio, and the like, but is preferably in the range of 0.01 to 5 μm, and more preferably in the range of 0.05 to 3 μm.

The coating liquid for forming a charge generation layer can prevent the occurrence of image defects by filtering foreign substances and agglomerates before coating.

(Charge transport layer)
The charge transport layer contains a charge transport material (CTM).
As the charge transporting substance, known compounds can be used, for example, carbazole derivative, oxazole derivative, oxaziazole derivative, thiazole derivative, thiazazole derivative, triazole derivative, imidazole derivative, imidazolone derivative, imidazolidine derivative, bisimidazole Lysine derivative, styryl compound, hydrazone compound, pyrazoline compound, oxazolone derivative, benzimidazole derivative, quinazoline derivative, benzofuran derivative, aclysin derivative, phenazine derivative, aminostilben derivative, triarylamine derivative, phenylenediamine derivative, stilben derivative, benzidine derivative, Examples thereof include poly-N-vinylcarbazole, poly-1-vinylpyrene, and poly-9-vinylanthracene. These compounds can be used alone or in combination of two or more.

These charge transporting substances can be used alone or in a form of being dispersed in a known binder resin.

As the binder resin for the charge transport layer, a known resin can be used. For example, a polycarbonate resin, a polyacrylate resin, a polyester resin, a polystyrene resin, a styrene-acrylic nitrile copolymer resin, a polymethacrylic acid ester resin, etc. Examples thereof include a styrene-methacrylic acid ester copolymer resin. Among these, polycarbonate resin is preferable, and further, bisphenol A (BPA), bisphenol Z (BPZ), dimethyl BPA type polycarbonate resin, BPA-dimethyl BPA copolymer and other types of polycarbonate resin have crack resistance and abrasion resistance. , It is preferable from the viewpoint of charging characteristics.

When forming a charge transport layer, a binder resin and a charge transport substance are dissolved in a solvent to prepare a coating liquid, and the coating liquid is applied on the charge generating layer to a certain layer thickness to form a coating film. It can be formed by drying the coating film.

Known methods for applying the coating liquid for forming a charge transport layer include, for example, a dip coating method, a spray coating method, a spinner coating method, a bead coating method, a blade coating method, a beam coating method, a slide hopper method, and a circular slide hopper method. In particular, in the present invention, the circular slide hopper method using the circular slide hopper coating device described later is preferable.

The method for drying the coating film can be appropriately selected depending on the type of solvent and the layer thickness, but heat drying is preferable.

Examples of the solvent for dissolving the binder resin and the charge transporting substance include toluene, xylene, methyl ethyl ketone, cyclohexanone, ethyl acetate, butyl acetate, methanol, ethanol, propanol, butanol, tetrahydrofuran, 1,4-dioxane, 1,3-. Examples include dioxolane.
The solvent used to prepare the coating liquid for forming the charge transport layer is not limited to the above.

The mixing ratio of the binder resin and the charge transporting substance is preferably in the range of 10 to 500 parts by mass with respect to 100 parts by mass of the binder resin, and is preferably in the range of 20 to 100 parts by mass. Is more preferable.

The thickness of the charge transport layer varies depending on the characteristics of the charge transport substance and the binder resin, the mixing ratio thereof, and the like, but is preferably in the range of 5 to 40 μm, and more preferably in the range of 10 to 30 μm.

A known antioxidant can be added to the charge transport layer, and for example, the antioxidant described in JP-A-2000-305291 can be used.

<Underlay layer>
The electrophotographic photosensitive member according to the present invention may have an undercoat layer between the conductive substrate and the photosensitive layer. The undercoat layer has a barrier function and an adhesive function.
In the undercoat layer, a binder resin such as casein, polyvinyl alcohol, nitrocellulose, ethylene-acrylic acid copolymer, polyamide, polyurethane, and gelatin is dissolved in a known solvent, and the same known coating as the above-mentioned charge generation layer is applied. Formed by the method. As the binder resin, it is preferable to use an alcohol-soluble polyamide resin.

The undercoat layer may also contain a metal oxide for the purpose of adjusting resistance. Similarly, the undercoat layer may contain inorganic fine particles such as various conductive fine particles for the purpose of adjusting resistance. Examples of the metal oxide include alumina, zinc oxide, titanium oxide, tin oxide, antimony oxide, indium oxide, and bismuth oxide. Ultrafine particles such as tin-doped indium oxide, antimony-doped tin oxide and zirconium oxide can also be used.
These metal oxides may be used alone or in combination of two or more. When two or more types are mixed and used, they may take the form of a solid solution or a fused solution. Such metal oxides are preferably contained in the undercoat layer in the form of fine particles, in which case the number average primary particle size is preferably 0.3 μm or less, and more preferably 0.1 μm or less. preferable.
The method for measuring the number average primary particle size of the metal oxide is the same as that of the metal oxide fine particles contained in the surface protective layer (see below).

As the solvent that can be used for forming the undercoat layer, a solvent that satisfactorily disperses the above-mentioned inorganic fine particles such as conductive fine particles and metal oxides and dissolves a binder resin such as a polyamide resin is preferable.
Specific examples thereof include alcohols having 2 to 4 carbon atoms such as ethanol, n-propyl alcohol, isopropyl alcohol, n-butanol, tert-butanol and sec-butanol. These alcohols are preferable because they exhibit good solubility and coating performance in a public polyamide resin as a binder resin.
The following auxiliary solvents can be used in combination with such a solvent in order to improve the storage stability and the dispersibility of the inorganic fine particles. Examples of the co-solvent that can obtain a preferable effect include methanol, benzyl alcohol, toluene, cyclohexanone, tetrahydrofuran and the like.

The binder resin concentration at the time of forming the coating liquid can be appropriately selected according to the thickness of the undercoat layer and the like.

When the inorganic fine particles are dispersed, the mixing ratio of the inorganic fine particles to the binder resin is preferably in the range of 20 to 400 parts by mass with respect to 100 parts by mass of the binder resin, and is in the range of 50 to 200 parts by mass. It is more preferable to use the inside.
Examples of the means for dispersing the inorganic fine particles include, but are not limited to, an ultrasonic disperser, a ball mill, a sand grinder, and a homomixer.

As a method for drying the undercoat layer, a known drying method can be appropriately selected depending on the type of solvent and the thickness to be formed, and heat drying is particularly preferable.

The thickness of the undercoat layer is preferably in the range of 1 to 30 μm, more preferably in the range of 0.1 to 15 μm, and further preferably in the range of 0.3 to 10 μm.

<Surface protective layer>
The surface protective layer is preferably composed of at least a resin obtained by polymerizing a crosslinkable polymerizable compound and metal oxide fine particles. Further, the surface protective layer may contain a known charge transporting substance, lubricant particles, various antioxidants, and the like, if necessary.

The surface protective layer contains a resin obtained by polymerizing a crosslinkable polymerizable compound as a binder resin. In the surface protective layer, in addition to the resin obtained by polymerizing a crosslinkable polymerizable compound, known resins such as polyester resin, polycarbonate resin, polyurethane resin, and silicone resin can be used in combination.

(1) Crosslinkable polymerizable compound Examples of the crosslinkable polymerizable compound that can be used for the surface protective layer include a radically polymerizable compound having two or more radically polymerizable reactive groups, and examples of the radically polymerizable compound include radically polymerizable compounds. As the radically polymerizable reactive group, a radically polymerizable monomer having at least one of an acryloyl group and a methacryloyl group is preferable.

Examples of these radically polymerizable monomers include the following compounds, but the radically polymerizable monomers are not limited thereto.

The above radically polymerizable monomer is known and can be obtained as a commercially available product.
Here, R represents the following acryloyl group, and R'represents the following methacryloyl group.

(2) Metal oxide fine particles The surface protective layer preferably contains metal oxide fine particles.
As the metal oxide fine particles, tin oxide fine particles, zinc oxide fine particles, titanium oxide fine particles and aluminum oxide fine particles are preferable.
The average primary particle size of the number of metal oxide fine particles is preferably in the range of 1 to 300 nm, and more preferably in the range of 3 to 100 nm.

(2.1) Method for measuring the average primary particle size of the number of metal oxide fine particles The average primary particle size of the number of metal oxide fine particles is determined by the scanning electron microscope "JSM-7401F" (manufactured by JEOL Ltd.). An automatic image processing and analysis device "LUZEX (registered trademark) AP" (Co., Ltd.) takes a 10000x magnified photograph and randomly captures 300 particles with a scanner to capture photographic images (excluding agglomerated particles). ) Made by Nireco) Software Ver. The binarization process is performed using 1.32, the horizontal ferret diameter is calculated for each, and the average value is calculated as the number average primary particle size.
The horizontal ferret diameter refers to the length of the side of the circumscribed rectangle parallel to the x-axis when the image of the metal oxide fine particles is binarized.

(2.2) Surface Modification of Metal Oxide Fine Particles The metal oxide fine particles contained in the surface protective layer are preferably modified with a coupling agent, and further, a coupling agent having a reactive organic group. The one surface-modified with is more preferable.

(2.2.1) Coupling Agent As the coupling agent for surface-modifying the metal oxide fine particles, a coupling agent that reacts with a hydroxy group or the like existing on the surface of the metal oxide fine particles is preferable, and these coupling agents. Examples thereof include a silane coupling agent and a titanium coupling agent.
As the coupling agent, a coupling agent having a reactive organic group is preferable for the purpose of further increasing the hardness of the surface protective layer, and as the coupling agent having a reactive organic group, a cup having a radically polymerizable reactive group is used. Ring agents are preferred. These radically polymerizable reactive groups can also react with a crosslinkable polymerizable compound to form a strong protective film.
As the coupling agent having a radically polymerizable reactive group, a silane coupling agent having a radically polymerizable reactive group such as a vinyl group, an acryloyl group or a methacryloyl group is preferable, and a silane coupling agent having such a radically polymerizable reactive group is preferable. Examples of the agent include the following known compounds.

S-1: CH ₂ = CHSi (CH ₃ ) (OCH ₃ ) ₂
S-2: CH ₂ = CHSi (OCH ₃ ) ₃
S-3: CH ₂ = CHSiCl ₃
S-4: CH ₂ = CHCOO (CH ₂ ) ₂ Si (CH ₃ ) (OCH ₃ ) ₂
S-5: CH ₂ = CHCOO (CH ₂ ) ₂ Si (OCH ₃ ) ₃
S-6: CH ₂ = CHCOO (CH ₂ ) ₂ Si (OC ₂ H ₅ ) (OCH ₃ ) ₂
S-7: CH ₂ = CHCOO (CH ₂ ) ₃ Si (OCH ₃ ) ₃
S-8: CH ₂ = CHCOO (CH ₂ ) ₂ Si (CH ₃ ) Cl ₂
S-9: CH ₂ = CHCOO (CH ₂ ) ₂ SiCl ₃
S-10: CH ₂ = CHCOO (CH ₂ ) ₃ Si (CH ₃ ) Cl ₂
S-11: CH ₂ = CHCOO (CH ₂ ) ₃ SiCl ₃
S-12: CH ₂ = C (CH ₃ ) COO (CH ₂ ) ₂ Si (CH ₃ ) (OCH ₃ ) ₂
S-13: CH ₂ = C (CH ₃ ) COO (CH ₂ ) ₂ Si (OCH ₃ ) ₃
S-14: CH ₂ = C (CH ₃ ) COO (CH ₂ ) ₃ Si (CH ₃ ) (OCH ₃ ) ₂
S-15: CH ₂ = C (CH ₃ ) COO (CH ₂ ) ₃ Si (OCH ₃ ) ₃
S-16: CH ₂ = C (CH ₃ ) COO (CH ₂ ) ₂ Si (CH ₃ ) Cl ₂
S-17: CH ₂ = C (CH ₃ ) COO (CH ₂ ) ₂ SiCl ₃
S-18: CH ₂ = C (CH ₃ ) COO (CH ₂ ) ₃ Si (CH ₃ ) Cl ₂
S-19: CH ₂ = C (CH ₃ ) COO (CH ₂ ) ₃ SiCl ₃
S-20: CH ₂ = CHSi (C ₂ H ₅ ) (OCH ₃ ) ₂
S-21: CH ₂ = C (CH ₃ ) Si (OCH ₃ ) ₃
S-22: CH ₂ = C (CH ₃ ) Si (OC ₂ H ₅ ) ₃
S-23: CH ₂ = CHSi (OC ₂ H ₅ ) ₃
S-24: CH ₂ = C (CH ₃ ) Si (CH ₃ ) (OCH ₃ ) ₂
S-25: CH ₂ = CHSi (CH ₃ ) Cl ₂
S-26: CH ₂ = CHCOOSi (OCH ₃ ) ₃
S-27: CH ₂ = CHCOOSi (OC ₂ H ₅ ) ₃
S-28: CH ₂ = C (CH ₃ ) COOSi (OCH ₃ ) ₃
S-29: CH ₂ = C (CH ₃ ) COOSi (OC ₂ H ₅ ) ₃
S-30: CH ₂ = C (CH ₃ ) COO (CH ₂ ) ₃ Si (OC ₂ H ₅ ) ₃
S-31: CH ₂ = CHCOO (CH ₂ ) ₂ Si (CH ₃ ) ₂ (OCH ₃ )
S-32: CH ₂ = CHCOO (CH ₂ ) ₂ Si (CH ₃ ) (OCOCH ₃ ) ₂
S-33: CH ₂ = CHCOO (CH ₂ ) ₂ Si (CH ₃ ) (ONHCH ₃ ) ₂
S-34: CH ₂ = CHCOO (CH ₂ ) ₂ Si (CH ₃ ) (OC ₆ H ₅ ) ₂
S-35: CH ₂ = CHCOO (CH ₂ ) ₂ Si (C ₁₀ H ₂₁ ) (OCH ₃ ) ₂
S-36: CH ₂ = CHCOO (CH ₂ ) ₂ Si (CH ₂ C ₆ H ₅ ) (OCH ₃ ) ₂

As the silane coupling agent, a silane compound having a reactive organic group capable of radical polymerization may be used in addition to the above S-1 to S-36. These silane coupling agents can be used alone or in admixture of two or more.

(2.2.2) Method for surface modification of metal oxide fine particles When surface modification is performed, 0.1 to 100 parts by mass of a coupling agent and 50 to 5000 parts by mass of a solvent are used with respect to 100 parts by mass of the metal oxide fine particles. It is preferable to modify the surface using a wet media dispersion device. The surface can be modified by the dry method.

Hereinafter, a surface modification method for producing metal oxide fine particles uniformly surface-modified with a coupling agent will be described.

By wet pulverizing a slurry (suspension of solid particles) containing metal oxide fine particles and a coupling agent, the metal oxide fine particles are made finer and at the same time, surface modification of the fine particles progresses. Then, by removing the solvent and pulverizing it, metal oxide fine particles uniformly surface-modified with a coupling agent can be obtained.

The wet media dispersion type device, which is a surface modification device, crushes agglomerated particles of metal oxide fine particles by filling a container with beads as media and rotating a stirring disk mounted perpendicular to the rotation axis at high speed. It is an apparatus having a step of crushing and dispersing.
As for the configuration of the dispersion type apparatus, there is no problem as long as the metal oxide fine particles are sufficiently dispersed when the surface is modified and the surface can be modified. For example, vertical / horizontal type, continuous type / Various styles such as batch type can be adopted. Specifically, a sand mill, an ultra visco mill, a pearl mill, a Glen mill, a dyno mill, an agitator mill, a dynamic mill and the like can be used. In these dispersion-type devices, fine pulverization and dispersion are performed by impact crushing, friction, shearing, shear stress, etc. using a pulverizing medium (media) such as balls or beads.

As the beads used in the wet media dispersion type apparatus, balls made of glass, alumina, zircon, zirconia, steel, flint stone or the like can be used, but those made of zirconia or zircon are particularly preferable.
As the size of the beads, those having a diameter of about 1 to 2 mm can be usually used, but those having a diameter of about 0.1 to 1.0 mm are preferably used.

Various materials such as stainless steel, nylon, and ceramic can be used for the inner wall of the disc or container used for the wet media dispersion device, but in particular, the inner wall of the disc or container made of ceramic such as zirconia or silicon carbide is used. Is preferable.

By the wet treatment as described above, metal oxide fine particles surface-modified with a coupling agent can be obtained.
The above-mentioned surface-modified metal oxide fine particles are preferably contained in the range of 30 to 250 parts by mass with respect to 100 parts by mass of the crosslinkable polymerizable compound from the viewpoint of improving the abrasion resistance of the surface protective layer. ..

(3) Formation of surface protective layer When forming a surface protective layer, a crosslinkable polymerizable compound, surface-modified metal oxide fine particles, and if necessary, other resins, polymerization initiators, lubricant particles, and oxidation are used in the solvent. A coating solution is prepared by adding an inhibitor, etc., the coating solution is applied onto the photosensitive layer to a certain thickness to form a coating film, and the coating film is naturally dried or heat-dried to be cured (polymerization reaction). ) Can be formed.

Known methods for applying the coating liquid for forming the surface protective layer include, for example, a dip coating method, a spray coating method, a spinner coating method, a bead coating method, a blade coating method, a beam coating method, a slide hopper method, and a circular slide hopper method. In particular, in the present invention, the circular slide hopper method using the circular slide hopper coating device described later is preferable.

The thickness of the surface protective layer is preferably in the range of 0.2 to 10 μm, more preferably in the range of 0.5 to 6 μm.

(3.1) Solvent As the solvent used for forming the surface protective layer, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, 2-methyl-2-propanol, benzyl alcohol, etc. Methyl isopropyl ketone, methyl isobutyl ketone, methyl ethyl ketone, cyclohexane, toluene, xylene, dichloromethane, ethyl acetate, butyl acetate, 2-methoxyethanol, 2-ethoxyethanol, tetrahydrofuran, 1,4-dioxane, 1,3-dioxolane, pyridine, Examples thereof include, but are not limited to, diethylamine.

(3.2) Polymerization Initiator As a method for polymerizing a crosslinkable polymerizable compound that can be used in the surface protective layer, a method using an electron beam cleavage reaction or light or heat in the presence of a radical polymerization initiator is used. The polymerization reaction can be carried out by the method used.
When the polymerization reaction is carried out using a radical polymerization initiator, either a photopolymerization initiator or a thermal polymerization initiator can be used as the polymerization initiator. In addition, both light and heat initiators can be used in combination.

Examples of the thermal polymerization initiator include 2,2'-azobisisobutyronitrile, 2,2'-azobis (2,4-dimethylazobisvaleroniryl), and 2,2'-azobis (2-methylbutyro). Azo compounds such as nitrile), benzoyl peroxide (BPO), di-tert-butyl hydroperoxide, tert-butyl hydroperoxide, chlorobenzoyl peroxide, dichlorobenzoyl peroxide, bromomethyl benzoyl peroxide, lauroyl peroxide and the like. Examples thereof include thermal polymerization initiators such as oxides.

Examples of the photopolymerization initiator include diethoxyacetophenone, 2,2-dimethoxy-1,2-diphenylethane-1-one, 1-hydroxy-cyclohexyl-phenyl-ketone, and 4- (2-hydroxyethoxy) phenyl- (2). -Hydroxy-2-propyl) ketone, 2-benzyl-2-dimethylamino-1- (4-morpholinophenyl) butanone-1 (Irgacure 369: manufactured by BASF Japan), 2-hydroxy-2-methyl-1-phenyl Acetophenone such as propane-1-one, 2-methyl-2-morpholino (4-methylthiophenyl) propane-1-one, 1-phenyl-1,2-propanedione-2- (o-ethoxycarbonyl) oxime or Ketal photopolymerization initiators, benzoin, benzoin methyl ether, benzoin ethyl ether, benzoin isobutyl ether, benzoin isopropyl ether and other benzoin ether photopolymerization initiators, benzophenone, 4-hydroxybenzophenone, methyl o-benzoylbenzoate, 2- Benzophenone-based photopolymerization initiators such as benzoylnaphthalene, 4-benzoylbiphenyl, 4-benzoylphenyl ether, acrylicized benzophenone, 1,4-benzoylbenzene, 2-isopropylthioxanthone, 2-chlorothioxanthone, 2,4-dimethylthioxanthone, Examples thereof include thioxanthone-based photopolymerization initiators such as 2,4-diethylthioxanthone and 2,4-dichlorothioxanthone.

Other photopolymerization initiators include ethylanthraquinone, 2,4,6-trimethylbenzoyldiphenylphosphine oxide, 2,4,6-trimethylbenzoylphenylethoxyphosphine oxide, and bis (2,4,6-trimethylbenzoyl) phenylphosphine oxide. Okid (Irgacure 819: manufactured by BASF Japan), bis (2,4-dimethoxybenzoyl) -2,4,4-trimethylpentylphosphine oxide, methylphenylglioxyester, 9,10-phenanthrene, aclysine compound, Examples thereof include triazine compounds and imidazole compounds.

Further, those having a photopolymerization promoting effect can be used alone or in combination with the above-mentioned photopolymerization initiator. For example, triethanolamine, methyldiethanolamine, ethyl 4-dimethylaminobenzoate, isoamyl 4-dimethylaminobenzoate, ethyl benzoate (2-dimethylamino), 4,4'-dimethylaminobenzophenone and the like can be mentioned.

As the polymerization initiator used for the surface protective layer, a photopolymerization initiator is preferable, an alkylphenone-based compound and a phosphine oxide-based compound are preferable, and an initiator having an α-hydroxyacetophenone structure or an acylphosphine oxide structure is more preferable. preferable.
These polymerization initiators may be used alone or in admixture of two or more.
The content of the polymerization initiator is preferably in the range of 0.1 to 40 parts by mass, and more preferably in the range of 0.5 to 20 parts by mass with respect to 100 parts by mass of the crosslinkable polymerizable compound. is there.

(3.3) Other Additives In addition to these, the surface protective layer may contain lubricant particles, antioxidants and the like, if necessary.

Examples of the lubricant particles include fluorine atom-containing resin particles.
Examples of the fluorine atom-containing resin particles include tetrafluoroethylene resin, tetrafluoroethylene chloride resin, hexafluoroethylene chloride propylene resin, vinyl fluoride resin, vinylidene fluoride resin, ethylene difluoride resin, and these. It is preferable to appropriately select one or more of the copolymers, but tetrafluoroethylene resin and vinylidene fluoride resin are particularly preferable.

(3.4) Polymerization reaction of surface protective layer In the polymerization reaction of surface protective layer, the coating film is irradiated with active rays to generate radicals for polymerization, and cross-linking by intermolecular and intramolecular cross-linking reaction is performed. It is preferable to form and cure to produce a cured resin.
As the active ray, light such as ultraviolet rays and visible light and an electron beam are preferable, and ultraviolet rays are particularly preferable from the viewpoint of ease of use.

As the ultraviolet light source, any light source that generates ultraviolet rays can be used without limitation.
For example, a low pressure mercury lamp, a medium pressure mercury lamp, a high pressure mercury lamp, an ultrahigh pressure mercury lamp, a carbon arc lamp, a metal halide lamp, a xenon lamp, a flash (pulse) xenon, an ultraviolet LED and the like can be used.
The irradiation conditions differ depending on each lamp, but the irradiation amount of the active ray is usually in the range of 1 to ²⁰ mJ / cm ² , preferably in the range of 5 to 15 mJ / cm ² . The output voltage of the light source is preferably in the range of 0.1 to 5 kW, particularly preferably in the range of 0.5 to 3 kW.

As an electron beam source, there are no particular restrictions on the electron beam irradiation device, and in general, as an electron beam accelerator for such electron beam irradiation, a curtain beam type that can obtain a large output at a relatively low cost is effective. Used. The accelerating voltage during electron beam irradiation is preferably in the range of 100 to 300 kV. The absorbed dose is preferably in the range of 0.005 Gy to 100 kGy (0.5 rad to 10 Mrad).

The irradiation time of the active ray is a time during which the required irradiation amount of the active ray can be obtained, specifically, 0.1 second to 10 minutes is preferable, and 1 second to 5 minutes is more preferable from the viewpoint of polymerization efficiency or work efficiency. ..

In the formation of the surface protective layer, the surface protective layer can be dried before and after the irradiation of the active rays and during the irradiation of the active rays, and the timing of drying can be appropriately selected in combination with the irradiation conditions of the active rays. ..
The drying conditions of the surface protective layer can be appropriately selected depending on the type of solvent used for the coating liquid, the thickness of the surface protective layer, and the like.
The drying temperature is preferably in the range of room temperature (25 ° C.) to 180 ° C., and particularly preferably in the range of 80 to 140 ° C. The drying time is preferably 1 to 200 minutes, particularly preferably 5 to 100 minutes. By drying the surface protective layer under the above drying conditions, the amount of solvent contained in the surface protective layer can be controlled within the range of 20 to 75 ppm.

By providing the surface protective layer on the photosensitive layer as described above, the hardness of the surface of the photoconductor can be increased, the abrasion resistance can be improved, and the durability can be improved.

《Image forming device》
The image forming apparatus using the electrophotographic photosensitive member manufactured by the method for producing an electrophotographic photosensitive member of the present invention forms at least a charging means for charging the surface of the photoconductor and an electrostatic latent image on the surface of the photoconductor. It has an exposure means for processing, a developing means for developing an electrostatic latent image with toner to form a toner image, and a transfer means for transferring the toner image to a transfer material. Further, there are those provided with a fixing means for fixing the toner image transferred to the transfer material and a cleaning means for removing the residual toner on the photoconductor.

FIG. 6 is an explanatory sectional view showing a configuration in an example of the image forming apparatus.
The image forming apparatus 500 is called a tandem type color image forming apparatus, and is fed with four sets of image forming units (image forming units) 10Y, 10M, 10C, 10Bk, an endless belt-shaped intermediate transfer unit 7, and paper feeding. It includes means 21 and fixing means 24. A document image reading device SC is arranged above the main body A of the image forming device 500.

The image forming unit 10Y for forming a yellow image includes a charging means 2Y, an exposure means 3Y, a developing means 4Y, a primary transfer roller 5Y as a primary transfer means, and a cleaning unit 10Y arranged around a drum-shaped photoconductor 1Y. It has means 6Y.
The image forming unit 10M for forming a magenta-colored image includes a drum-shaped photoconductor 1M, a charging means 2M, an exposure means 3M, a developing means 4M, a primary transfer roller 5M as a primary transfer means, and a cleaning means 6M.
The image forming unit 10C for forming a cyan image includes a drum-shaped photoconductor 1C, a charging means 2C, an exposure means 3C, a developing means 4C, a primary transfer roller 5C as a primary transfer means, and a cleaning means 6C.
The image forming unit 10Bk for forming a black image includes a drum-shaped photoconductor 1Bk, a charging means 2Bk, an exposure means 3Bk, a developing means 4Bk, a primary transfer roller 5Bk as a primary transfer means, and a cleaning means 6Bk.
The image forming apparatus 500 uses the photoconductor produced by the above-described method for producing an electrophotographic photosensitive member of the present invention as at least one of the photoconductors 1Y, 1M, 1C and 1Bk.

The four image forming units 10Y, 10M, 10C and 10Bk are composed of the photoconductors 1Y, 1M, 1C and 1Bk, the charging means 2Y, 2M, 2C and 2Bk, and the exposure means 3Y, 3M, 3C and 3Bk. It is composed of rotating developing means 4Y, 4M, 4C and 4Bk, and cleaning means 6Y, 6M, 6C and 6Bk for cleaning the photoconductors 1Y, 1M, 1C and 1Bk.

The image forming units 10Y, 10M, 10C and 10Bk have the same configuration except that the colors of the toner images formed on the photoconductors 1Y, 1M, 1C and 1Bk are different, respectively. In the following, the image forming unit 10Y will be taken as an example in detail. explain.

The image forming unit 10Y arranges the charging means 2Y, the exposure means 3Y, the developing means 4Y and the cleaning means 6Y around the photoconductor 1Y which is an image forming body, and displays a yellow (Y) toner image on the photoconductor 1Y. It is what forms. Further, in the present embodiment, at least the photoconductor 1Y, the charging means 2Y, the developing means 4Y, and the cleaning means 6Y are provided so as to be integrated in the image forming unit 10Y.

The charging means 2Y is a means for giving a uniform potential to the photoconductor 1Y. In the present invention, examples of the charging means include a contact or non-contact roller charging method.

The exposure means 3Y is a means for forming an electrostatic latent image corresponding to a yellow image by exposing the photoconductor 1Y to which a uniform potential is applied by the charging means 2Y based on an image signal (yellow). Therefore, as the exposure means 3Y, one composed of LEDs and imaging elements in which light emitting elements are arranged in an array in the axial direction of the photoconductor 1Y, a laser optical system, or the like is used.

The developing means 4Y comprises, for example, a developing sleeve having a built-in magnet and holding a developer and rotating, and a voltage applying device for applying a DC and / or AC bias voltage between the developing sleeve and the photoconductor. is there.

The fixing means 24 is, for example, a heat roller fixing composed of a heating roller having a heating source inside and a pressure roller provided in a state of being pressure-contacted so as to form a fixing nip portion on the heating roller. There is a method.

The cleaning means 6Y is composed of a cleaning blade and a brush roller provided on the upstream side of the cleaning blade.

The image forming apparatus 500 is configured by integrally coupling a photoconductor and components such as a developing means and a cleaning means as a process cartridge (image forming unit), and the image forming unit can be detachably attached to and detached from the apparatus main body. It may be configured. Further, at least one of a charging means, an exposure means, a developing means, a transfer means, and a cleaning means is integrally supported together with a photoconductor to form a process cartridge (image forming unit), and a detachable single image is formed on the main body of the apparatus. The unit may be detachable by using a guide means such as a rail of the main body of the device.

The endless belt-shaped intermediate transfer unit 7 has an endless belt-shaped intermediate transfer body 70 as a semi-conductive endless belt-shaped second image carrier that is wound by a plurality of rollers and rotatably supported.

Images of each color formed by the image forming units 10Y, 10M, 10C and 10Bk are placed on the endless belt-shaped intermediate transfer body 70 which is rotated by the primary transfer roller 5Y, 5M, 5C and 5Bk as the primary transfer means. It is sequentially transferred to form a composite color image. The transfer material (image support for carrying the fixed final image: plain paper, transparent sheet, etc.) P housed in the paper feed cassette 20 is fed by the paper feed means 21, and the plurality of intermediate rollers 22A, It is conveyed to the secondary transfer roller 5b as the secondary transfer means via the 22B, 22C, 22D, and the resist roller 23, and is secondarily transferred onto the transfer material P to collectively transfer the color image. The transfer material P to which the color image is transferred is fixed by the fixing means 24, sandwiched between the paper ejection rollers 25, and placed on the paper ejection tray 26 outside the machine. Here, the transfer support of the toner image formed on the photoconductor such as the intermediate transfer body or the transfer material is collectively referred to as a transfer medium.

On the other hand, after the color image is transferred to the transfer material P by the secondary transfer roller 5b as the secondary transfer means, the residual toner is removed from the endless belt-shaped intermediate transfer body 70 by which the transfer material P is curvature-separated by the cleaning means 6b. Toner.

During the image forming process, the primary transfer roller 5Bk is always in contact with the photoconductor 1Bk. The other primary transfer rollers 5Y, 5M and 5C abut on the corresponding photoconductors 1Y, 1M and 1C only during color image formation.

The secondary transfer roller 5b comes into contact with the endless belt-shaped intermediate transfer body 70 only when the transfer material P passes through the transfer material P and the secondary transfer is performed.

Further, the housing 8 can be pulled out from the device main body A via the support rails 82L and 82R.

The housing 8 includes image forming portions 10Y, 10M, 10C and 10Bk, and an endless belt-shaped intermediate transfer unit 7.

The image forming portions 10Y, 10M, 10C and 10Bk are arranged in columns in the vertical direction. An endless belt-shaped intermediate transfer unit 7 is arranged on the left side of the photoconductors 1Y, 1M, 1C and 1Bk in the drawing. The endless belt-shaped intermediate transfer unit 7 includes an endless belt-shaped intermediate transfer 70, primary transfer rollers 5Y, 5M, 5C and 5Bk, which can be rotated by winding rollers 71, 72, 73 and 74, and a cleaning means 6b. It consists of.

Although the image forming apparatus 500 shown in FIG. 6 shows a color laser printer, it can be similarly applied to a monochrome laser printer and copying. Further, the exposure light source may be a light source other than the laser, for example, an LED light source.

The toner used in the image forming apparatus as described above is not particularly limited, but a toner having a shape coefficient SF of less than 140 with a true sphere as 100 is preferable. When the shape coefficient SF is less than 140, good transferability and the like can be obtained, and the image quality of the obtained image is improved. From the viewpoint of improving image quality, the toner particles constituting the toner preferably have a volume average particle size in the range of 2 to 8 μm.

The toner particles usually contain a binder resin and a colorant, and optionally contain a release agent. As the binder resin, the colorant, and the release agent, materials conventionally used for toner can be used, and the present invention is not particularly limited.

The method for producing the above-mentioned toner particles is not particularly limited, and for example, a normal pulverization method, a wet molten spheroidizing method produced in a dispersion medium, suspension polymerization, dispersion polymerization, emulsion polymerization aggregation method, etc. Examples thereof include known polymerization methods.

Further, as an externalizing agent, silica having an average particle size of about 10 to 300 nm, inorganic fine particles such as titania, and an abrasive having an average particle size of about 0.2 to 3 μm can be externally added to the toner particles in an appropriate amount. Further, the toner particles and a carrier composed of ferrite beads or the like having an average particle size in the range of 25 to 45 μm can be mixed and used as a two-component developer.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited thereto.

<< Preparation of electrophotographic photosensitive member >>
Electrophotographic photosensitive members 101 and 102 were prepared as follows.

<Preparation of electrophotographic photosensitive member 101>
(Preparation of the object to be coated)
(1) Preparation of Conductive Substrate A conductive substrate was prepared by cutting and cleaning the surface of a cylindrical aluminum support (JIS A 6063 series) so as to have an outer diameter of φ29.96 mm and a length of 360 mm.

(2) Formation of Intermediate Layer The following composition was dispersed for 10 hours using a sand mill. Then, it was diluted 2-fold with the same solvent, left overnight, and then filtered through a Rigimesh 5 μm filter to prepare a coating solution for forming an intermediate layer.
This coating liquid was applied onto the conductive support by a dip coating method so that the thickness after drying was 2 μm, and an intermediate layer was formed.

Binder: Polyamide resin (Daiamide X4685: manufactured by Daicel Eponic)
100 parts by mass Inorganic fine particles: Titanium oxide (STM500SAS: manufactured by TAYCA Corporation) 300 parts by mass Solvent: 1440 parts by mass of ethanol Solvent: 1-propanol 360 parts by mass

(3) Formation of Charge Generation Layer The following compositions were mixed and dispersed for 10 hours using a sand mill to prepare a coating liquid for forming a charge generation layer.
This coating liquid was applied onto the intermediate layer by a dip coating method to form a charge generation layer having a thickness of 0.3 μm after drying.

Binder: Polyvinyl butyral resin (# 6000-C) 10 parts by mass Charge generator: Y-titanyl phthalocyanine pigment (Cu-Kα characteristic X-ray diffraction spectrum measurement has a maximum diffraction peak at at least 27.3 °)
20 parts by mass Solvent: t-butyl acetate 700 parts by mass Solvent: 4-methoxy-4-methyl-2-pentanone 300 parts by mass

(4) Formation of Charge Transport Layer The following composition was dissolved and mixed to prepare a coating liquid for forming a charge transport layer.
This coating liquid was applied onto the charge generation layer by a dip coating method to form a charge transport layer having a thickness of 16 μm after drying, and a work piece having an outer diameter of φ30 mm was prepared.

Binder: Polycarbonate resin (Iupilon Z-300: manufactured by Mitsubishi Gas Chemical Company)
145.0 parts by mass Charge transport material: 4,4'-dimethyl-4 "-(β-phenylstyryl) triphenylamine 116.0 parts by mass Antioxidant: Dibutylhydroxytoluene 11.6 parts by mass Solvent: tetrahydrofuran 711. 4 parts by mass Solvent: 173.4 parts by mass Additive: Silicone oil (KF-96, manufactured by Shin-Etsu Chemical Co., Ltd.) 0.071 parts by mass

(Formation of surface protective layer)
A coating liquid for forming a surface protective layer having the following composition was prepared.

Binder: Polycarbonate resin (TS2050, manufactured by Teijin Co., Ltd.) 100 parts by mass Charge transporter: 4,4'-dimethyl-4 "-(β-phenylstyryl) triphenylamine 60 parts by mass Antioxidant: Dibutylhydroxytoluene 6 parts by mass Part Solvent: tetrahydrofuran 808 parts by mass Solvent: toluene 197 parts by mass Additive: Silicone oil (KF-96, manufactured by Shin-Etsu Chemical Co., Ltd.) 0.12 parts by mass

The coating liquid had a viscosity η = 110 mPa · sec, a solid content concentration = 10.9% by volume, and a coating liquid density ρ = 0.92 g / cm ³ .
The viscosity (25 ° C.) was measured using a rotary viscometer (TVB15 type viscometer manufactured by Toki Sangyo Co., Ltd.).

Next, using a circular slide hopper coating device (see FIG. 1), which is provided with four coaters and in which the dispensing pipes for supplying the coating liquid to each coater are connected at one place by a connecting pipe, on the object to be coated. A surface protective layer was formed on the surface.
In the circular slide hopper coating device, the coating liquid for forming the surface protective layer is sent to each coater in advance to raise the liquid level of the connecting pipe by 1.5 m from the coating liquid discharge port position of the coater, and then the valve. Was closed and the air was sealed.
The inner diameter of the liquid supply pipe was φ3 mm, and the inner diameter of the connecting pipe was φ4.0 mm.

The set value (target value) of the wet film thickness of the surface protective layer is set to 120 μm (dry film thickness 13.1 μm), the supply liquid amount for four coaters is 40.7 ml / min, and the transport speed of the object to be coated is set. It was set to 15 mm / sec.
Since the above-prepared coating solution for forming a surface protective layer has a slow drying rate, K = 0.7 was set. At this time, it was confirmed that K × {(η ・ v) / (ρ ・ g)} ^1/2 = 299 μm, and the wet film thickness setting value of 120 μm was smaller than this.

Next, an object to be coated having an outer diameter of φ30 mm was transported, and a coating liquid for forming a surface protective layer was applied to prepare an electrophotographic photosensitive member 101 on which a surface protective layer was formed.

<Preparation of electrophotographic photosensitive member 102>
In the production of the electrophotographic photosensitive member 101, the electrophotographic photosensitive member 102 was produced in the same manner except that a circular slide hopper coating device in which each liquid supply tube was not connected by a connecting tube was used.

《Evaluation》
<Thickness of surface protective layer>
For each of the prepared electrophotographic photosensitive members, 1000 similar electrophotographic photosensitive members were continuously produced in each coater, and the thickness of the surface protective layer for a total of 20 sheets, one for every 50 sheets, was determined by the eddy current method. The average value was calculated by measuring using a film thickness measuring device "ISOSCOPE FMP30 type" (manufactured by Fisher Instruments Co., Ltd.).
The measurement results are shown in Table I.

<Summary>
As is clear from Table I, the electrophotographic photosensitive member produced by the method for producing an electrophotographic photosensitive member of the present invention has a maximum difference in the average film thickness of the surface protective layer of 0.3 μm, whereas the comparison is made. In the electrophotographic photosensitive member of the example, the difference in the average film thickness of the surface protective layer is 1.0 μm at the maximum.
From the above, it is a method of manufacturing an electrophotographic photosensitive member using a slide hopper coating device that supplies a coating liquid from one liquid supply pump to a plurality of coaters, and the coating liquid is applied from the liquid supply pump to a plurality of coaters. The liquid supply pipe to be supplied is connected via the connecting pipe, and the coating liquid and the gas are sealed in the connecting pipe, and the liquid level in the connecting pipe is set higher than the position of the coating liquid discharge port of the coater to form a film. It is said that the method for producing an electrophotographic photosensitive member is useful for suppressing the variation in film thickness between a plurality of coaters, enabling uniform film formation, and enabling stable coating over a long period of time. confirmed.

100 Circular slide hopper coating device 110 Storage tank 111 Piping 120 Liquid supply pump 121 Piping 122 Divider 123, 124 Liquid supply pipe 125 Connecting pipe 126 Valve 130 Coater 131 Coating liquid discharge port 132 Coating liquid distribution slit 133 Coating liquid distribution chamber 134 Slide Surface 135 Piping 136 Valve 140 Base material 150 Air bearing CL Coating liquid F Coating coating L1 to L4 Line

Claims (4)

A method for manufacturing an electrophotographic photosensitive member using a slide hopper coating device that supplies a coating liquid from one liquid supply pump to a plurality of coaters.
The liquid supply pipes that supply the coating liquid from the liquid supply pump to the plurality of coaters are connected via a connecting pipe, the coating liquid and the gas are sealed in the connecting pipe, and the liquid level in the connecting pipe is filled. A method for producing an electrophotographic photosensitive member, which comprises forming a film with a height higher than the position of a coating liquid discharge port of the coater. The inner diameters of the liquid supply pipes are all the same.
The inner diameter of the connecting pipe is made larger than the inner diameter of the liquid supply pipe, and
The method for producing an electrophotographic photosensitive member according to claim 1, wherein the height of the liquid level in the connecting pipe is increased by 1 m or more from the position of the coating liquid discharge port. The method for producing an electrophotographic photosensitive member according to claim 2, wherein the inner diameter of the connecting tube is 1.2 times or more the inner diameter of the liquid supply tube. The method for producing an electrophotographic photosensitive member according to any one of claims 1 to 3, wherein the following relational expressions (1) and (2) are satisfied.
Q = w × πD × v… (1)
w <K × {(η ・ v) / (ρ ・ g)} ¹ / ² … (2)
(Here, Q: the flow rate of the coating liquid, w: the wet film thickness, D: the outer diameter of the object to be coated, v: the transport speed of the object to be coated, K: the coating film setting speed and the amount of sagging. It is a coefficient to be determined, K = 0.7, η: coating liquid viscosity, ρ: coating liquid density, g: gravitational acceleration.)

Images