JPH01106065A - Photosensitive body and its production - Google Patents

Abstract

PURPOSE:To reduce defects in a picture such as black spots, etc. by specifying a ratio of content of a binder to a carrier generating material and a film thickness of a carrier generating layer. CONSTITUTION:A carrier generating layer 2 is formed on an electroconductive base 1 and a carrier transfer layer 4 is formed thereon. A photosensitive layer 5 is constituted of the carrier generating layer 2 and the carrier transfer layer 4 and a carrier generating material 10 and a carrier transfer material are incorporated in the carrier generating layer 2. The proportion of the carrier generating material to a binder is <=1/2, delamination of the carrier generating layer 21 is regulated to >=1mum and the binder is substantially insoluble in a solvent to be used for forming the carrier transfer layer 4. By this constitution, elimination or decrease of surface potential due to local carrier injection from an electroconductive base 1 side are prevented and generation of black spots in a picture is also prevented even if reversal development is executed.

Description

DETAILED DESCRIPTION OF THE INVENTION A. Field of Industrial Application The present invention relates to a photoreceptor (particularly an electrophotographic photoreceptor using an organic photoconductive substance) and a method for manufacturing the same.

BACKGROUND OF THE INVENTION Conventionally, electrophotographic photoreceptors sensitive to visible light have been widely used in copying machines, printers, and the like.

As such electrophotographic photoreceptors, inorganic photoreceptors provided with a photosensitive layer mainly composed of an inorganic photoconductive substance such as selenium, zinc oxide, or cadmium sulfide are widely used. However, such inorganic photoreceptors do not necessarily satisfy the characteristics such as photosensitivity, thermal stability, moisture resistance, and durability required of electrophotographic photoreceptors for copying machines and the like. For example, since selenium crystallizes due to heat or fingerprint stains when touched, the above-mentioned characteristics as an electrophotographic photoreceptor tend to deteriorate. Further, electrophotographic photoreceptors using cadmium sulfide have poor humidity resistance and durability, and electrophotographic photoreceptors using zinc oxide have problems in durability. Also, selenium,
Both electrophotographic photoreceptors made of cadmium sulfide have the disadvantage of being toxic and having significant restrictions in manufacturing and handling.

In order to overcome these problems with inorganic photoconductive materials, attempts have been made to use various organic photoconductive materials in the photosensitive layer of electrophotographic photoreceptors, and active research and development has been carried out in recent years. ing. For example, Japanese Patent Publication No. 50-10496 describes an organic photoreceptor having a photosensitive layer containing poly-N-vinylcarbazole and 2,4,7-)dinitro-9-fluorenone. However, this photoreceptor also has insufficient sensitivity and durability. In order to improve these shortcomings, we developed an organic photoreceptor with high sensitivity (and durability) by assigning the carrier-propagating function and carrier-transporting function to different substances in the photosensitive layer. In such so-called function-separated type electrophotographic photoreceptors, it is possible to select substances that exhibit each function from a wide range of materials, so it is possible to create electrophotographic photoreceptors with arbitrary characteristics. can be obtained relatively easily.Therefore, it is expected that an organic photoreceptor with high sensitivity and durability can be obtained.

FIG. 5 shows a functionally separated electrophotographic photoreceptor using such an organic photoconductive substance.

This electrophotographic photoreceptor has a structure in which a carrier generation layer 6 and a carrier transport layer 4 are sequentially laminated on a conductive substrate 1, and is used for negative charging. That is, the photosensitive layer 8 is composed of the carrier generation layer 6 and the carrier transport layer 4. The carrier generation layer 6 has a carrier generation substance 10 dispersed in a binder resin, and the content ratio of the carrier generation substance and the binder resin is usually 2:
The ratio is about 1 to 1:1. Further, the carrier generation layer 6 is a thin layer, and the layer thickness (film thickness) K is usually about 0.1 to 0.3 μm.
It is formed. Note that the layer thickness (film thickness) of the photosensitive layer 8 is usually 15 to 30 μm for reasons such as obtaining a sufficient acceptance potential.
It is said to be about m.

In an electrophotographic photoreceptor having the above-mentioned layer structure, since the mobility of holes is higher than that of electrons when used with negative charging, it is possible to use photoconductive materials with hole transport properties that have good properties. This is advantageous in terms of sensitivity, etc.

In contrast, few electron-transporting materials have excellent properties or are carcinogenic, making them unsuitable for use. For this reason, the above-mentioned photoreceptor is used for negative charging. In this case, it is advantageous to use a material with a high hole transport ability in order to achieve high sensitivity.

However, in the above-mentioned photoreceptor, carrier injection from the conductive substrate or the lower layer side tends to occur when negatively charged, as shown in FIG. The cause of such local carrier injection is not clear, but it is thought to be caused by defects or non-uniformity on the surface of the conductive substrate or non-uniformity in the charge generation layer.

Such local carrier injection causes the following problems.

That is, in recent years, for example, reversal development has been widely adopted in printers that involve digital processing, but in the reversal development method, a toner image is formed on the exposed area (the area where the surface charge has disappeared, VL), and the unexposed area is A toner image is not formed on the portion (portion VH where the surface charge is retained).

However, in the reversal development method, when the surface charge microscopically disappears or decreases in the unexposed area due to carrier injection from the substrate or lower layer as described above, toner is developed in that area, resulting in so-called fog. It becomes an image. This type of capri is different from normal fog, and is a phenomenon that occurs when the surface charge on the photoreceptor microscopically disappears or decreases during reversal development as described above, and is called "black spot". There is. These black spots are caused by toner locally adhering to the white background, so they are much more noticeable than when the black background is white, and they significantly reduce the quality of the image, and are inappropriate image defects. be.

When developing an electrostatic latent image using the photoreceptor described above using the regular development method, the surface charge disappears and toner does not adhere to the reduced area and is not developed, so that the so-called Image defects called "white spots" occur, leading to a decline in image quality (but in this case, they are white spots in a black background, so they are hard to notice).

In order to solve the above problems, for example, the following measures can be considered.

That is, as shown in FIG. 6, a blocking layer 7 is provided between the carrier generation layer 6 and the conductive substrate 1, and the
It is conceivable to prevent carrier injection from. However, in this case, the transport of holes and/or electrons is suppressed by the blocking layer 7 even during light irradiation, leading to a decrease in photosensitivity, an increase in residual potential, and the absolute value of the potential of the exposed area +Vt , + increases, and the stability of 1VLl during repeated use is also impaired.

Other countermeasures include reducing the content of carrier transport material (hereinafter sometimes referred to as CTM) in the carrier transport layer 4 of FIGS. 5 and 6, or
It is possible to change the type of P binder resin.

All of these are intended to reduce the hole transport ability of the carrier transport layer 40 to suppress carrier injection to the surface of the photoreceptor, but in this photoreceptor, like the photoreceptor shown in FIG. 5 described above, Decrease in photosensitivity, increase in residual potential, I
This results in an increase in VLI, a decrease in IVLI stability during repeated use, and a decrease in temperature characteristics, and particularly at low temperatures, photoreceptor characteristics are significantly deteriorated, such as increases in lVt and l.

Furthermore, when coating and forming the carrier transport layer on the carrier generation layer, uniform coating is difficult, and the state of the carrier generation layer is not uniform, resulting in uneven sensitivity and image unevenness.

As described above, there has been no known photoreceptor that eliminates image defects such as black spots and has good photoreceptor characteristics, and a technical solution to these mutually contradictory problems has been desired.

The purpose of the present invention is to significantly reduce image defects such as black spots, provide good sensitivity characteristics, residual potential characteristics, potential stability during repeated use, and temperature characteristics, and provide good coating properties. It is an object of the present invention to provide a photoreceptor that does not cause sensitivity unevenness or image unevenness and can improve production yield, and a method for manufacturing the same.

21 Structure and Effects of the Invention The first invention provides a photoreceptor in which a carrier transport layer is provided on a carrier generation layer containing a carrier generation substance and a binder substance. content or more, the carrier transport substance is contained in the carrier generation layer, and the binder substance is substantially insoluble in the solvent used to form the carrier transport layer. This is related.

A second invention provides a carrier generation layer containing a carrier generation substance, a binder substance, and a carrier transport substance, and in which the content ratio of the carrier generation substance to the binder substance (carrier generation substance/binder substance) is 1/2 or less. The present invention relates to a method for producing a photoreceptor in which the binder substance is substantially insoluble in the solvent used to form a carrier transport layer on the carrier generation layer, with a film thickness of 1 μm or more.

In the present invention, it is extremely important that the content ratio (weight ratio) of the carrier-generating substance to the binder substance is 1/2 or less, and that the thickness of the carrier-generating layer is 1 μm or more.

That is, conventionally, the content ratio of the carrier-generating substance to the binder substance was usually as large as about 271 to 1/1, and the thickness of the carrier-generating layer was usually as small as about 0.1 to 0.3 μm. In contrast, the present invention has remarkable features in that the content ratio of the carrier-generating substance is quite small, 172 or less, and the thickness of the carrier-generating layer is quite large, 1 μm or more.

By employing such a unique structure in the photoreceptor, in the present invention, it is possible to prevent the surface charge from disappearing or decreasing due to local injection of carriers from the conductive substrate side. Therefore, even when reversal development is performed, black spots do not occur on the image, and a remarkable effect can be achieved in that a high-quality image without image defects can be obtained. Moreover, even when regular development is performed, white spots do not occur, and similarly high-quality images can be provided.

The reason why local carrier injection from the substrate side can be prevented is not clear, but it is thought to be as follows.

That is, in the conventional photoreceptor as shown in FIG.
Carriers (holes) injected from the substrate 1 side easily pass through the carrier generation layer 6 and reach the surface of the photoreceptor via the carrier transport layer 4 having high hole transport properties. In other words, the carrier generation layer 6 does not function as a barrier to local carrier injection.

This is because the carrier generation layer 6 is thin as described above.
This seems to be due to reasons such as the low concentration of the binder substance in the carrier generation layer. Conversely, the carrier generation layer should perform the function of generating carriers during light irradiation and injecting them into the carrier transport layer, so it is natural that it cannot function as a barrier to local carrier injection. be.

In contrast, in the photoreceptor of the present invention, the content ratio of the binder substance in the carrier generation layer is very large, which is clearly different from the structure in which the binder substance is contained at a low concentration as in the prior art. There is. That is, even if local carrier injection is to occur, the carrier generation layer effectively functions as a barrier to carrier injection because of the high concentration of the binder substance.

Moreover, since the carrier generation layer has a large thickness of 1 μm or more, the carriers that are about to be injected cannot easily pass through the carrier generation layer, which sufficiently prevents local carrier injection. It is.

In addition, in the carrier generation layer, when the content ratio of the carrier generation substance to the binder substance is set to 1/2 or less and the film thickness of the carrier generation layer is the same as before, fewer photocarriers are generated during light irradiation (, However, in the present invention, since the carrier generation layer has a thickness of 1 μm or more, the content of the carrier generation substance can be kept high as a whole, and the photosensitivity is insufficient. Never.

Furthermore, in the present invention, it is important that the carrier-generating layer also contains a carrier-transporting substance.

That is, if the carrier generation layer is composed of only a carrier generation substance and a binder substance, the thickness of the carrier generation layer becomes thicker (as the carrier generation layer becomes thicker, the transport distance of the carrier in the carrier generation layer increases, and as a result, the carrier generation layer becomes thicker). Similarly, when the content of the binder substance in the carrier generation layer is increased, the carrier transport ability is decreased.

On the other hand, in the present invention, since the carrier generation layer also contains a carrier transport substance, even if the thickness of the carrier generation layer is increased and the concentration of the binder substance is increased, the carrier generation layer will not be generated. The transport ability of photocarriers does not deteriorate (in fact, it improves. Therefore, it is possible to always enjoy good sensitivity characteristics, IVLI characteristics, residual potential characteristics, sensitivity characteristics and potential stability during repeated use.Here, The carrier transport substance can be added when forming the carrier generation layer.

Furthermore, it is important that the binder material forming the carrier generation layer is substantially insoluble in the solvent for forming the carrier transport layer.

That is, when the carrier transport layer is formed by dip coating, if the carrier generation layer dissolves or swells, potential performance, etc. (for example, VL
, VH), but according to the present invention, such inconvenience does not occur.

Moreover, since the carrier generation layer has a thickness of 1 μm or more, which is much thicker than conventional ones, the coating properties of the carrier transport layer are good, especially the dip coating properties, which is convenient for manufacturing photoreceptors. Yes, it is easy to manufacture products of uniform quality.

Furthermore, in the dip coating method, since the coating liquid contained in the container 2 is used repeatedly, the binder substance of the carrier generation layer may dissolve in the solvent for forming the carrier transport layer (solvent of the coating liquid). In this case, each time dip coating is repeated, the constituent components of the carrier generation layer are eluted into the coating solution for forming the carrier transport layer, and the components of the coating solution change. This results in variations in the thickness, electrophotographic performance, etc. of the resulting photosensitive layer. Furthermore, once the usage limit is reached, the coating liquid must be discarded, leading to an increase in the cost of materials and requiring cumbersome manual operations such as cleaning the container each time.

In this regard, according to the present invention, the binder material of the carrier generation layer is substantially insoluble in the solvent used to form the carrier transport layer, so that the constituent components of the carrier generation layer do not dissolve into the coating solution. Therefore, it is possible to suppress changes in the composition of the coating solution, prevent variations in film thickness and performance of the photoreceptor, and supply a uniform product. Yield during coating is also improved, and material loss of the coating solution is prevented, reducing costs. It is possible to solve various problems in manufacturing photoreceptors, such as reduction in size. Therefore, this makes it possible to form layers with high efficiency, high precision, and uniformity, which is advantageous in the production of photoreceptors.

In particular, by forming the carrier transport layer by a dip coating method, it is possible to form the layer with extremely high efficiency, which, together with the above-mentioned advantages, is very advantageous in the production of photoreceptors.

As described above, according to the present invention, the carrier generation layer itself can be given a function as a barrier against local carrier injection, and the carrier generation layer maintains good optical carrier generation and transport ability. Shitsuru. In addition, various problems in photoreceptor production can be solved, a uniform and even layer can be formed with high efficiency and yield, and the carrier transport layer has good coating properties. Therefore, image unevenness, black spots,
It can significantly reduce image defects called white spots and stably provide high-quality images, and maintain good sensitivity characteristics, residual potential characteristics, and sensitivity characteristics and potential stability during repeated use. There is no deterioration in temperature characteristics. In other words, the mutually contradictory problems of significantly reducing image defects such as black spots and maintaining good photoreceptor characteristics have been technically solved, and a photoreceptor particularly suitable for reversal development has been realized. be.

In the carrier generation layer, the granular carrier generation substance and the left carrier transport substance are generally bound together by a binder substance. That is, they are dispersed in the layer in the form of pigments.

The carrier transporting substance contained in the carrier generation layer preferably has an ionization potential that matches that of the carrier generation substance. It is thought that this allows the above-mentioned effects to be better achieved. Also,
The carrier transport material is preferably one that has excellent compatibility with the binder material.

As a result, turbidity and opacity do not occur even if the amount of the binder substance is increased, so the mixing ratio with the binder substance can be very wide. Generator layer b' - Uniform and stable, resulting in better sensitivity and charging characteristics, making it possible to produce a photoreceptor capable of forming clear images with higher sensitivity.

Furthermore, especially when used in repeated transfer type electrophotography, it is possible to achieve the effect that fatigue deterioration does not occur.

The structure of a photoreceptor, such as an electrophotographic photoreceptor, based on the present invention can take various forms.

A general configuration is illustrated in FIGS. 1 and 2.

In the photoreceptor shown in FIG. 1, a gear generation layer 2 based on the present invention is provided on a conductive substrate 1, and a carrier transport layer 4 is provided on this. A photosensitive layer 5 is configured. The carrier generation layer 2 contains a carrier generation substance 10 and a carrier transport substance (which is compatible with the binder resin).

In the photoreceptor shown in FIG. 2, an intermediate layer or subbing layer 3 is provided between the conductive substrate 1 and the photosensitive layer 5.
Its main function is as an adhesive layer. The thickness of layer 3 is preferably within the range of 0.03 to 20 μm.

In the photoreceptor shown in FIGS. 1 and 2, an intermediate layer having a blocking function or the like may be provided between the carrier generation layer and the carrier transport layer.

Further, a protective layer (protective film) may be formed on the surface of the photoreceptor in order to improve printing durability, for example, a synthetic resin film may be coated.

In the carrier generation layer, the content ratio of the carrier generation substance to the binder substance should be 1/2 or less, preferably 1/3 to 1/2o, and 1/4 to 1/2o.
It is more preferable to set it to 10. When the content ratio of the carrier-generating substance is larger than the above range, black spots and the like appear significantly or tend to appear. However, if the proportion of the carrier-generating substance is too small, the photosensitivity and the like will be rather reduced.

The thickness of the carrier generation layer is 1 μm or more, preferably 2 μm or more, and more preferably in the range of 5 to 25 μm. If the film thickness is smaller than the above range, carrier injection cannot be prevented or is difficult to prevent.However, if the film thickness is too large, photocarriers have to travel a long distance, and sufficient transport capacity is generally not achieved. Therefore, the residual potential tends to increase during repeated use.The thickness of the carrier generation layer is preferably 3/4 or less of the thickness of the entire photosensitive layer; When the ratio is higher than the above range, the charging potential tends to decrease.

The film thickness ratio of the carrier generation layer and the carrier transport layer is (film thickness of carrier generation layer: film thickness of carrier transport layer) = (1:20)
) to (1:1) is preferable.

The thickness of the carrier transport layer is preferably 2 μm or more. If the film thickness is less than 2 μm, the surface of the carrier transport layer may be mechanically damaged during repeated use due to development, cleaning, etc. Parts may be scratched off, or black lines may appear on the image.

The thickness of the entire photosensitive layer is preferably within the range of 10 to 40 μm, and more preferably within the range of 15 to 30 μm. If the film thickness is smaller than the above range, the charging potential will be low due to the thinness, and the printing durability will also tend to decrease. In addition, if the film thickness is larger than the above range, the residual potential will increase on the contrary, and the same phenomenon as described above will occur when the carrier generation layer is too thick, making it difficult to obtain sufficient transport performance. appears, and as a result, the residual potential tends to increase during repeated use.

The content of the carrier transport substance in the carrier generation layer is preferably 1 to 100 parts by weight, more preferably 5 to 50 parts by weight, based on 100 parts by weight of the binder substance.

If the content of the carrier transport substance is larger than the above range, the film strength tends to decrease, and if the content is smaller than the above range, the carrier mobility in the CGL decreases, resulting in an increase in residual potential and a decrease in photosensitivity. This tends to cause image defects to occur.

The content ratio of the carrier-generating substance and the carrier-transporting substance in the carrier-generating layer is such that the weight ratio (carrier-generating substance:carrier-transporting substance)=(1: 100)~(5:
1), preferably (1:10) to (1:1
) is more preferable.

When a photosensitive layer is formed by dispersing a granular carrier-generating substance, the carrier-generating substance is powder with an average particle size of 5 μm or less and 0.1 μm or more, preferably 2 μm or more and 0.2 μm or more. is preferred. That is,
If the particle size is too large, dispersion in the layer tends to be poor, and if the particle size is too small, it tends to aggregate, which increases the resistance of the layer and increases crystal defects, resulting in a decrease in sensitivity and repeatability. , the charging ability tends to decrease, and there is a limit to miniaturization.

One of the features of the present invention is that the binder material of the carrier generation layer is substantially insoluble in the solvent used to form the carrier transport layer. There are no particular restrictions on the rough combination of solvent and binder material, but the following Table 1 may be mentioned.

Table 1 In addition, when a binder resin is used to form a carrier transport layer, undercoat layer, intermediate layer, etc., any binder resin can be used, but in particular, it is hydrophobic and has a high dielectric constant. High molecular weight polymers having the ability to form electrically insulating films are preferred. These polymers include
Examples include, but are not limited to, the following:

That is, polyethylene, polypropylene, vinyl chloride resin, vinyl acetate resin, epoxy resin, polyurethane resin,
Phenolic resin, polyhydroxystyrene resin, polyester resin, alkyd resin, polycarbonate resin,
silicone resin, melamine resin, met;1yyi/,y,
addition polymerization type resins such as ysw methacrylic resins, acrylic resins, polyvinylidene chloride, polystyrene, phenol formaldehyde resins, single polyaddition type resins, polycondensation type resins, and copolymer resins containing two or more of these repeating units; Insulating resins such as vinyl chloride-vinyl acetate copolymer resin, vinyl chloride-vinyl acetate-maleic anhydride copolymer resin, styrene-butadiene copolymer resin, vinylidene chloride-acrylonitrile copolymer resin, polyvinyl butyral, etc. Examples of the material include polymeric organic semiconductors such as N-vinylcarbazole.

The above binders can be used alone or as a mixture of two or more.

In addition to the binder resin described above, for example, polyvinyl alcohol, ethyl cellulose, carboxymethyl cellulose, casein, N-alkoxymethylated nylon, starch, etc. are used for the undercoat layer that functions as an adhesive layer or the like.

As a binder for the protective layer provided as necessary,
Volume resistance 10'Ω・cm or more, preferably 10Ω・cm
Above, more preferably 10Ω・cI! One or more transparent resins are used. The binder may be a resin that is cured by light or heat (for example, thermosetting acrylic resin, silicone resin, epoxy resin, urethane resin, urea resin, phenol resin, etc.). , polyester resins, alkyd resins, melamine resins, photocurable cinnamic acid resins, and copolymerized or condensed resins thereof, and all other photocurable or thermosetting resins used in electrophotographic materials can be used.

In addition, the protective layer contains improvements in processability and physical properties (crack prevention,
If necessary, a thermoplastic resin may be contained in an amount of less than 50% by weight for the purpose of imparting flexibility, etc.). Such thermoplastic resins include, for example, polypropylene, acrylic resin, methacrylic resin, vinyl chloride resin, vinyl acetate resin, epoxy resin, butyral resin, polycarbonate resin, silicone resin, or copolymer resins thereof, such as vinyl chloride-vinyl acetate- maleic anhydride copolymer resin,
Polymeric organic semiconductors such as IJ-N-vinylcarbazole and other thermoplastic resins used in electrophotographic materials can all be used.

For the carrier transport layer, polycarbonate represented by the following general formula [I] and polycarbonate represented by the following general formula [■] are preferably used.

General formula [I]: (In this general formula, R'', R': hydrogen atom, substituted or unsubstituted aliphatic group, substituted or unsubstituted carbocyclic group, or substituted or device-substituted aromatic group) and at least one of Pi and Bi is a bulky group, R', R', R'', straight Pi, Pi, R', R''°: hydrogen atom, halogen atom, substituted or unsubstituted aliphatic group or a substituted or unsubstituted carbocyclic group, r: 10 to 1000.) General formula [■]: RRpi R゛°1 R", R', R', R", 1, R", R" , R”s
r: Same as above. W: An atomic group necessary to form a substituted or unsubstituted carbon ring or a substituted or unsubstituted heterocycle. ) That is, if polycarbonate of the above general formula [I] or (III) is used as the main component of the binder of the carrier transport layer, at least one of the central carbon atoms of the bisphenol A portion of these polycarbonates has a bulky content. ) m and f are bonded, or a ring is formed by the above W, so these R'' and/or R
Alternatively, W effectively prevents the molecular chains of polycarbonate from arranging in a specific direction. For this reason, polycarbonate does not crystallize and precipitate on the film surface during layer formation, resulting in lower yield due to abnormal protrusions,
Also, characteristic deterioration such as image defects due to toner filming can be prevented. Such a remarkable effect can be more fully exhibited if R' and G in the above general formula CI) are different from each other or are bonded asymmetrically. In the above general formula CII), the ring formed by W directly contributes to the above remarkable effect.

Furthermore, since these binders are polycarbonate-based, they can provide the photoreceptor with the excellent charging performance, repeatability, printing durability, and other characteristics that polycarbonate inherently exhibits. In particular, the mechanical strength of the carrier transport layer is improved, and since the carrier transport layer is the upper layer in a photoreceptor using negative electromagnetic conductivity as in the present invention, the effect of improving rigidity is greater (and the repeatability is also improved). .

These effects are remarkable in so-called cyclic polycarbonates of the general formula CII).

Among the above polycarbonates, in those represented by the general formula CI), it is essential that at least one of W and R'' is a bulky group, and such a bulky group has 3 or more carbon atoms. It is desirable that the bulky group has a steric hindrance effect that hinders the molecular chain alignment. Examples of such bulky groups include the following.

(However, R'' is a hydrogen atom, an alkyl group such as a methyl group,
H=)mcOOR (R is an alkyl group, an alkyl ester group represented by m≧1) (3), -Cm Ht m
+ Alkyl group represented by r (however, m≧4) (Chrysanthemum, ÷CH=)mcOOR'” alkyl ester group (however, R is an alkyl group, m≧2) Also, one of R1 and G is If it is a bulky group, the other may be a hydrogen atom or an alkyl group such as a methyl group.

Next, R” to R in the general formula CI”l, (T[]
The group No. 16 may be a hydrogen atom, a halogen atom such as CI, Br, or F, an alkyl group such as a methyl group, or a carbocyclic group such as a cyclohexyl ring.

In addition, in the polycarbonate of the general formula (I []), the W may form a 5- or 6-membered carbocyclic or heterocyclic ring (such rings include a cyclohexyl ring, a cyclopentyl ring, etc.). A substituent such as an acetyl group or an acetylamino group may be introduced into a part of the ring.

Specific examples of the above-mentioned polycarbonate include the following.

(I-1) CH.

CH,CL CH.

■ CH, -C) (-CH.

CH.

CH.

■ C00C,H.

(I-14) CH, -CH.

The CH=CL carrier generation layer can be provided by the following method.

(a) A method of applying a solution in which a carrier-generating substance, etc. is dissolved in a suitable solvent, or a solution in which a binder is added and mixed and dissolved.

(b) A method in which a carrier-generating substance, etc. is made into fine particles in a dispersion medium using a ball mill, a homomixer, a sand mill, an ultrasonic disperser, an attritor, etc., and a binder is added, mixed and dispersed, and the resulting dispersion is applied.

Dispersing the particles under the action of ultrasound in these methods allows for homogeneous dispersion.

Preferably, the viscosity of the solution or dispersion is between 1 and 1000 centipoise.

Further, the carrier transport layer can be formed by coating and drying a carrier transport substance alone or by dissolving and dispersing it together with the above-mentioned binder resin.

In this case, in order to contain the carrier transport substance in the carrier generation layer, the carrier transport substance is dissolved or dispersed in the solution (A) above or the dispersion liquid (C) in advance. There is a method b'--of adding a transport substance. In this case, it is preferable that the amount of the carrier transport substance added be within the range of 1 to 100 parts by weight per 100 parts by weight of the binder.

As the solvent or dispersion medium used for forming the layer, n
-butylamine, diethylamine, ethylenediamine,
Isopropanolamine, triethanolamine, triethylenediamine, N,N-dimethylformamide, acetone, methyl ethyl ketone, cyclohexanone, benzene, toluene, xylene, chloroform, 1,2-dichloroethane, dichloromethane, tetrahydrofuran,
Dioxane, methanol, ethanol, impropatol, ethyl acetate, butyl acetate, dimethyl sulfoxide and the like can be mentioned.

The photosensitive layer, undercoat layer, intermediate layer, protective layer, etc. can be provided by, for example, blade coating, dip coating, spray coating, roll coating, spiral coating, or the like. For example, blade coating is suitable for providing layers of a few μm.

Furthermore, the above-mentioned effects can be obtained by forming the carrier transport layer by dip coating. This dip coating method is used as a preferred coating processing method for electrophotographic photoreceptors,
It is usually applied in the following way. That is, as shown in FIG. 3, first, the support cylinder 14 whose upper opening is closed with the lid 13 is immersed in a container containing the coating liquid 11, and the handle 13a of said 13 is gripped to hold it in a predetermined position. Pull it up and apply it as quickly as possible. Such a coating method is described, for example, in Japanese Patent Publication No. 56-4.
No. 1310, Japanese Patent Publication No. 60-263157, Japanese Patent Publication No. 1983
This method is known from various publications such as No.-156065 and Japanese Unexamined Patent Publication No. 60-242461.

Carrier generating substances that can be used in the present invention include:
For example, α type, β type, X type, τ type, τ type, τ′ type, η type,
Examples include one or more selected from η'-type metal-free phthalocyanine, 7-thalocyanine pigments other than these, azo pigments, anthraquinone pigments, perylene pigments, polycyclic quinone pigments, methine squaric acid pigments, and the like.

Examples of azo pigments include the following.

(III-2) (III-5) A-N=N-Ar'-CH=CH-Ar"-N=N-A
(m-6) A-N=N-Ar'-CH=CH-Ar''-CH=CH
--Ar"-N=N-A ([-8) A-N=N-Ar'-N=N-Ar"-N=N-A(I
II-9) A-N=N-Ar'-N=N-Ar"-N=N-Ar"
--N=N-A -Ar"-N=N-A Cm-12) [However, in each of the above formulas, Ar' + Ar" and Ar": each substituted or unsubstituted carbocyclic aromatic cyclic group, R"+ R"+ R11 and R'4 = respectively,
At least one of the electron-withdrawing groups or hydrogen atoms is an electron-withdrawing group such as a cyano group (X is a hydroxy7 group, provided that RII and R゛° are each a hydrogen atom or a substituted or unsubstituted alkyl group) 5, t6 is a substituted or unsubstituted alkyl group or a substituted or unsubstituted aryl group>, Y is a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group, an alkoxy group, a carboxyl group, a sulfo group, a substituted or unsubstituted aryl group; Substituted carbamoyl group or substituted or unsubstituted sulfamoyl group (however, when m is 2 or more, mutually different groups may be used), 2 is substituted or unsubstituted carbocyclic aromatic ring or substituted or an atomic group necessary to constitute an unsubstituted heterocyclic aromatic ring, W" is a hydrogen atom, a substituted or unsubstituted amine group, a substituted or unsubstituted carbamoyl group, a carboxyl group or an ester group thereof, Ar ' is a substituted or unsubstituted aryl group, n is an integer of 1 or 2, m is an integer of 0 to 4)] Polycyclic quinone pigments of the following general formula (IV) group are also carriers. Can be used together as a generating substance.

General formula [■]: (However, in this general formula, represents an integer. ) Carrier transport substances that can be used in the present invention include, for example, carbazole derivatives, oxazole derivatives, oxadiazole derivatives, thiazole derivatives, thiadiazole derivatives, triazole derivatives, imidazole derivatives, imidasilone derivatives, imidazolidine derivatives, bisimidazolidine derivatives, and styryl compounds. , hydrazone compounds, pyrazoline derivatives, oxacilone derivatives, benzothiazole derivatives, benzimidazole derivatives, quinazoline derivatives, benzofuran derivatives, acridine derivatives, phenazine derivatives, aminostilbene derivatives, triarylamine derivatives, phenylenediamine derivatives, stilbene derivatives, poly-N- Examples include one or more selected from vinylcarbazole, poly-1-vinylpyrene, poly-9-vinylanthracene, and the like.

In addition, examples of carrier transport substances that have bipolar transport ability by themselves include metal phthalocyanines and various pigments.

Further, different carrier transport materials may be used in the carrier generation layer and the carrier transport layer.

The following general formula (V) or (VI
) styryl compounds can be used.

General formula [V]: R (However, in this general formula, R11, H1: substituted or unsubstituted alkyl group,
It represents an aryl group, and examples of substituents include an alkyl group, an alkoxy group, a substituted amino group, a hydroxyl group, a halogen atom, and an aryl group.

Ar"+Ar': represents a substituted or unsubstituted aryl group, and the substituent used is an alkyl group, an alkoxy group, a substituted amine group, a hydroxyl group, a halogen atom, or an aryl group.

R, R: Represents a substituted or unsubstituted aryl group or a hydrogen atom, and as a substituent, an alkyl group, an alkoxy group, a substituted amino group, a hydroxyl group, a halogen atom, or an aryl group is used. ) General formula [■]: (However, in this formula, W": substituted or unsubstituted aryl group, R'°: hydrogen atom, halogen atom, substituted or unsubstituted alkyl group, alkoxy group, amino group, Substituted amino group, hydroxyl group, R′“: substituted or unsubstituted aryl group, substituted or unsubstituted heterocyclic group) In addition, a hydrazone compound of the following general formula % can also be used as a carrier transport substance. be.

- Formula [■]: (However, in this formula, Bi8 and Bi0: Hydrogen atom or I/Rogen atom, respectively, Rso and R'': Each substituted or unsubstituted aryl group, Ar'': Substituted or unsubstituted Represents a substituted arylene group.) General formula [■]: (However, in this formula, R: a substituted or unsubstituted aryl group.

represents a substituted or unsubstituted carbazolyl group, or a substituted or unsubstituted heterocyclic group; Represents a substituted aralkyl group. ) General formula [■a]: (However, in this formula, R: methyl group, ethyl group, 2-hydroxyethyl group, or 2-chloroethyl group, R: methyl group, ethyl group, benzyl group, or phenyl group, R : Indicates a methyl group, ethyl group, benzyl group or phenyl group.

General formula [■b]: (However, in this formula, R is a substituted or unsubstituted 7-tyl group; R is a substituted or unsubstituted alkyl group, aralkyl group, or aryl group; R is a hydrogen atom, an alkyl group or an alkoxy group; R and R are the same or different groups consisting of a substituted or unsubstituted alkyl group, aralkyl group, or aryl group.) General formula [■]: (However, in this general formula, R: substituted or unsubstituted Aryl group or substituted or unsubstituted heterocyclic group, R: hydrogen atom, substituted or unsubstituted alkyl group, or substituted or unsubstituted aryl group, Q: hydrogen atom, halogen atom, alkyl group , a substituted amino group, an alkoxy group, or a cyano group, s: represents an integer of 0 or 1.) A pyrazoline compound represented by the following general formula [X] can also be used as a carrier transport substance.

General formula [X]: RN Go [However, in this general formula, l: 0 or 1, R and R: substituted or unsubstituted aryl group, R: substituted or unsubstituted aryl group or heterocyclic group, R and R: hydrogen atom, alkyl group having 1 to 4 carbon atoms,
or a substituted or unsubstituted aral group or aralkyl group (however, R'8 and R'° are not both hydrogen atoms, and when the above l is O, R is not a hydrogen atom). ] Further, an amine derivative of the following general formula [1] can also be used as a carrier transport substance.

General formula [■]: (In this general formula, Ar + Ar' represents a substituted or unsubstituted phenyl group, and a halogen atom, an alkyl group, a nitro group, or an alkoxy group is used as a substituent.

Ar: substituted or unsubstituted phenyl group, naphthyl group,
Represents an anthryl group, a fluorenyl group, and a heterocyclic group, and substituents include an alkyl group, an alkoxy group, a halogen atom, a hydroxyl group, an aryloxy group, an aryl group, an amine group, a nitro group, a piperidino group, a morpholino group, a naphthyl group, and anthryl. and substituted amino groups. However, an acyl group, an alkyl group, an aryl group, or an aralkyl group is used as a substituent for the substituted amino group. ) Furthermore, a compound of the first-order general formula [■] can also be used as a carrier transport substance.

General formula [■]: R"°R" (However, in this general formula, Ar'": represents a substituted or unsubstituted arylene group, R, R, R and R: a substituent or unsubstituted alkyl group , represents a substituted or unsubstituted aryl group, or a substituted or unsubstituted aralkyl group.) Furthermore, a compound of the following general formula [■] can also be used as a carrier transport substance.

General formula [XIII]: [However, in this formula, R″6, Bi°, R′″ and R are each a hydrogen atom, a substituted or unsubstituted alkyl group, a cycloalkyl group, an alkenyl group, R and R are each a hydrogen atom, a substituted or unsubstituted alkyl group having 1 to 40 carbon atoms, a cycloalkyl group,
Alkenyl group, cycloalkenyl group, aryl group, or aralkyl group (However, R and R jointly have 3 to 1 carbon atoms.
0 saturated or unsaturated hydrocarbon rings may be formed. ) atoms, halogen atoms, hydroxyl groups, substituted or unsubstituted alkyl groups, cycloalkyl groups, alkenyl groups,
Oryl group, aralkyl group, alkoxy group, amino group,
It is an alkylamino group or an arylamino group. ] The layer-forming coating liquid may contain a siloxane compound, which has the effect of smoothing the coating surface. Examples of siloxane compounds include dimethylpolysiloxane and methylphenylpolysiloxane. The amount added is preferably 1 to 10,000 P, more preferably 10 to 11,000 rIrI, based on the total amount of the coating liquid.

Furthermore, the photosensitive layer may contain one or more electron-accepting substances for the purpose of improving sensitivity, reducing residual potential, and reducing fatigue during repeated use. Examples of electron-accepting substances that can be used here include succinic anhydride, maleic anhydride, dibromosuccinic anhydride, phthalic anhydride, tetrachlorophthalic anhydride, tetrabromo phthalic anhydride, 3-nitro phthalic anhydride, 4- Nitrophthalic anhydride, pyromellitic anhydride, mellitic anhydride, tetracyanoethylene, tetracyanoquinodimethane, 0-dinitrobenzene, m-dinitrobenzene, 1,3.5-trinitrobenzene, varanitrobenzonitrile, picryl Chloride, quinone chlorimide, chloranil, pullmanil, dichlorodiquanovabenzoquinone, anthraquinone, dinitroanthraquinone, 9-fluorenylidene [dicyanomethylenemalonodinitrile], polynitro-9-fluorenylidene [dicyanomethylenemalonodinitrile] , picric acid, o-nitrobenzoic acid, p-
Examples include nitrobenzoic acid, 3.5-dinitrobenzoic acid, pentafluorobenzoic acid, 5-nitrosalicylic acid, 3.5-dinitrosalicylic acid, phthalic acid, mellitic acid, and other compounds with high electron affinity.

Further, the addition ratio of the electron-accepting substance is carrier-generating substance:electron-accepting substance in a weight ratio of 100:0.01 to 2.
00, preferably 100:0.1-100.

In addition, if a polymeric organic semiconductor having a fused aromatic ring or a heterocyclic ring in the side chain is used in the photosensitive layer together with the carrier transport substance described above, this polymeric organic semiconductor has the property of generating photocarriers by absorbing ultraviolet light. It effectively contributes to photosensitization, thus improving the tail of the discharge curve, absorbing most of the ultraviolet light at a particularly low level, and having a kind of filter effect on the ultraviolet light. Therefore, it has the effect of preventing the deterioration of the carrier transporting substance, and can sometimes improve the ultraviolet light stability and durability of the photosensitive layer.

Examples of the above-mentioned polymeric organic semiconductors include the following examples, but the present invention is not limited thereto.

(XIV-1) (XIV-2) (XIV-3) (XTV-4) (XrV-5) (XrV-6) (XIV-7) r (XIV-8) CH.

(XIV-9) CH.

CH.

(XIV-10) (XrV-15) mine C=0 Ward C,H.

(XrV-16) (XIV-17') CH.

(XIV-18) (XIV-19) (XIV-20) 100H-CH, + n Among the above-mentioned polymeric organic semiconductors, BoIJ-N-vinylcarbazole or its derivatives are highly effective and are preferred. used. Such poly-N-vinylcarbazole derivatives are those in which all or part of the carbazole ring in the repeating unit is substituted with various substituents, such as an alkyl group, a nitro group, an amino group, a hydroxy group, or a halogen atom. .

Furthermore, silicone oil may be present as a surface modifier. Further, an ammonium compound may be contained as a durability improver.

The protective layer may contain an ultraviolet absorber or the like for the purpose of protecting the photosensitive layer, if necessary.

The conductive substrate 1 on which the above photosensitive layer is to be provided is a metal plate, a metal drum, or a conductive thin layer coated with a conductive compound such as a conductive polymer, an oxide wing, or a metal such as aluminum, palladium, or gold. Paper by means of , vapor deposition, lamination, etc.

A material provided on a substrate such as a plastic film is used.

The photoreceptor of the present invention can be applied to various light sources such as halogen lamps, tungsten lamps, LEDs (light emitting diodes), gas lasers such as helium-neon, argon, and helium-cadmium, and semiconductor lasers.

The photoreceptor of the present invention has a wide variety of uses such as electrophotographic copying machines and printers.

E. Examples Hereinafter, the present invention will be explained in more detail with reference to Examples.
The present invention is not limited thereby, and of course includes other embodiments with various modifications.

<Manufacture of Photoreceptors> First, photoreceptors A to M of Examples and photoreceptors a to h of Comparative Examples were manufactured in the following manner. That is, the manufacturing procedure for each photoreceptor is common.

The structure and prescription of each photoreceptor are shown in FIG.

Compound 209 of the following structural formula (I) was mixed with a porcelain ball for 40 minutes.
After milling at rpm for 18 hours, a predetermined amount of binder resin (see Figure 4) and 10 g of carrier transport material were
A solution dissolved in 10,100 O dichloroethane was added and dispersed for a further hour, and the predetermined P/B ratio (referred to as the content ratio of the carrier-generating substance to the bangu substance (carrier-generating substance/binder substance) shown in Fig. 4) is as follows. same.

) A coating liquid for CGL (carrier generation layer) was prepared.

However, each photoreceptor has the following structural formula (II) in the CGL coating liquid.
10 g of I''l CTM (carrier transport material) was added.

Next, the CGL coating liquid was dip-coated onto an aluminum base having a diameter of 100 mm, a wall thickness of 1 mm, and a length of 320 mm to form a carrier generation layer having a predetermined thickness (see FIG. 4).

Furthermore, predetermined carrier transport substances 11 and 2 shown in FIG.
5.9 and a predetermined binder resin 15.9 are dissolved in 100 rnl of a predetermined solvent, the resulting solution is dip coated onto the carrier generation layer, and dried at a temperature of 90° C. for 1 hour to form a carrier transport layer. did.

As described above, each of the photoreceptors A to M and a =
h was produced.

That is, in each photoreceptor, the content of the resin in the carrier generation layer, the P/B ratio, the film thickness, the binder resin, the carrier transport substance used in the carrier transport layer, the binder substance, the layer forming solvent, and the photosensitive layer. The film thicknesses are mutually varied.

The substances shown in FIG. 4 are as follows.

Substance [I]: Substance [■]: <Evaluation of photoreceptor characteristics> Each of the 21 types of photoreceptors, photoreceptors A-M of the present invention and comparative photoreceptors a to ship j, was
Installed on a modified 1800MRJ (manufactured by Konishi Roku Photo Industry Co., Ltd.), the grid voltage was adjusted so that the VH was -600±10 (V), and reverse development was performed at a developing bias of -480 (V).The white background of the copied image was In addition to evaluating the black spots in the parts, the deviation of IVLI in the circumferential direction of the drum was also measured. However, VH is the potential of the unexposed area, that is, the black background area (0, D) of the original image (negative original image).

=1.3), and corresponds to the black background potential in regular development.

In addition, the evaluation of Kuropochi was performed using the image analysis device "Omnicon 30".
00 type" (manufactured by Takasu Seisakusho Co., Ltd.) to measure the particle size and number of black spots, and 10 black spots with a diameter of φ (diameter) of 0.05 mm or more were measured.
Judgment was made based on the number of pieces per rA.

The criteria for black spot evaluation are as shown in Table-2.

Table 2 Note that if the black spot determination result is ◎, ○, or Δ, it is practical, but if it is ×, it is not suitable for practical use.

FIG. 4 shows the results of black spot evaluation and the circumferential deviation of IVLI for each photoreceptor.

Summary> As shown in FIG. 4, photoreceptors A-M constructed based on the present invention have a P/B ratio ≦1/2 and a CGL thickness ≧1 μm, so they all have fewer black spots and Since CGL was insoluble in the CTL forming solvent, there was no circumferential unevenness in VL.

On the contrary, both comparative photoreceptors a and e have a PZB ratio of 1.
/2, there are many black spots because the CGL film thickness is too small. Photoreceptors b to d have a P/B ratio>1/
2, there are many black spots in all cases, regardless of the thickness of the CGL film.

Photoreceptors f, g, and h had large deviations in IVLI in the circumferential direction of the drum because the binder resin of the carrier generation layer was soluble in the solvent used to form the carrier transport layer. In addition, the above-mentioned drawbacks also occurred in terms of manufacturing.

[Brief explanation of the drawing]

1 to 4 show the present invention, and FIG.
FIG. 2 is a sectional view of each photoreceptor according to the present invention, FIG. 3 is a sectional view of a dip coating device, and FIG. 4 is a diagram showing the structure, prescription, and evaluation of each photoreceptor. 5 and 6 are cross-sectional views of each side of a conventional photoreceptor. In addition, in the symbols shown in the drawings, 1... Conductive substrate 2.6... Carrier generation layer (CGL) 3
......Undercoat layer 4...Carrier transport layer (CTL')5.
8...Photosensitive layer 10...!・Carrier generating substance (CGM) 1
1... Coating liquid 12... Container 13... Lid 14... Support cylinder. Agent Patent Attorney Hiroshi Aisaka Figure 3

Claims (1)

[Scope of Claims] 1. In a photoreceptor in which a carrier transport layer is provided on a carrier generation layer containing a carrier generation substance and a binder substance, the content ratio of the carrier generation substance to the binder substance (carrier generation substance /binder substance) is 1/2 or less, and the carrier generation layer has a thickness of 1
μm or more, the carrier-generating layer contains a carrier-transporting substance, and the binder substance is substantially insoluble in a solvent used to form the carrier-transporting layer. 2. A carrier generation layer containing a carrier generation substance, a binder substance, and a carrier transport substance, and in which the content ratio of the carrier generation substance to the binder substance (carrier generation substance/binder substance) is 1/2 or less, with a thickness of 1 μm or more and forming a carrier transport layer on the carrier generation layer by dip coating. A method for producing an insoluble photoreceptor.