JPS60250350A - Photosensitive body for positive electrostatic charge - Google Patents

Abstract

PURPOSE:To form a photosensitive body having high carrier generating efficiency and excellent photoconductivity and to form a satisfactorily visible image by incorporating a specific bis-azo compd. as an essential component into a charge generating phase and a styryl compd. or amine deriv. as an essential component into a charge transfer layer. CONSTITUTION:The photosensitive body has a photosensitive layer 4 consisting of the carrier generating phase and carrier transfer phase. The carrier generating material (CGM) consisting essentially of the bis-azo compd. expressed by formula I [A is formula II, etc. (Z is an atom group necessary for constituting an arom. ring or heterocycle, Y is H, OH, carboxyl, etc.)] is incorporated into the carrier generating phase at 20-40 proportion by pts.wt. to 100 a binder resin. The carrier transfer material (CTM) consisting essentially of at least either of the styryl compd. expressed by formula III (R<3>, R<4> are alkyl, etc., R<5> is phenyl, etc., R<6> is H, halogen, etc.) or the amine deriv. expressed by formula IV(Ar<2>, Ar<3> are phenyl, Ar<4> is phenyl, naphthyl, etc.) is incorporated into the carrier transfer phase at 30-150 proportion to 100 the binder resin. The CGM and CTM may be provided as a single mixed layer 6 or may be provided as a separated function type on a carrier transfer layer 3.

Description

DETAILED DESCRIPTION OF THE INVENTION 1. Industrial Field of Application The present invention relates to a positively charging photoreceptor, for example, a positively charging electrophotographic photoreceptor, which has a photosensitive layer consisting of a carrier generation phase and a carrier transport phase. .

2. Prior Art Conventionally, inorganic photoreceptors having a photosensitive layer containing an inorganic photoconductive substance such as selenium, zinc oxide, or cadmium sulfide as a main component have been widely used as electrophotographic photoreceptors. However, such inorganic photoreceptors do not necessarily satisfy the characteristics required for electrophotographic photoreceptors, such as sensitivity, thermal stability, moisture resistance, and durability. for example,
Since selenium crystallizes due to heat, adhesion of dirt such as fingerprints, etc., its properties as an electrophotographic photoreceptor tend to deteriorate.

Further, when cadmium sulfide is used, there are problems in moisture resistance and durability, and when zinc oxide is used, there are problems in durability. Furthermore, selenium and cadmium sulfide have significant restrictions in manufacturing and handling.

In order to overcome the drawbacks of inorganic photoreceptors as described above,
Recently, the use of various organic photoconductive substances as materials for photosensitive layers of electrophotographic photoreceptors has been actively developed and researched.

For example, in Japanese Patent Publication No. 50-10496, poly-N-
An organic photoreceptor having a photosensitive layer containing vinylcarbazole and 2.4.7-)dinitro-9-fluorenone is described. However, this photoreceptor is not necessarily satisfactory in sensitivity and durability. In order to improve these drawbacks, we developed an organic photoreceptor with high sensitivity and durability by assigning the carrier storage function and carrier transport function to different substances in the photosensitive layer. Attempts are being made. In such so-called function-separated type electrophotographic photoreceptors, it is possible to select substances that exhibit each function from a wide range, so it is relatively easy to produce electrophotographic photoreceptors with arbitrary characteristics. It is possible to do so.

Many substances have been proposed as carrier-generating substances that are effective for such functionally separated electrophotographic photoreceptors.

Examples of using inorganic substances include, for example, Japanese Patent Publication No. 43-1
As described in Japanese Patent No. 6198, there is amorphous selenium. Although this is combined with an organic carrier transporting substance, the carrier generation layer made of amorphous selenium has the disadvantage of being crystallized by heat or the like and deteriorating its properties, as described above.

In addition, many FC electrophotographic photoreceptors have been proposed using organic dyes or organic pigments as carrier-generating substances, such as:
Those having a photosensitive layer containing a bisazo compound are disclosed in JP-A-47-37543, JP-A-55-22834, JP-A-54-79632, and JP-A-56-1.
This is already known from Publication No. 16040 and the like. However, electrophotographic photoreceptors using these bisazo compounds are not necessarily satisfactory in terms of sensitivity, residual potential, or even stability during repeated use, and furthermore, the selection range of materials to be used as carrier transport materials is limited. However, the electrophotographic photoreceptor does not fully satisfy the wide range of demands in the electrophotographic process that electrophotographic photoreceptors undergo.

Moreover, although known bisazo compounds exhibit relatively good sensitivity in the short or medium wavelength range, they lack sensitivity in the long wavelength range, and for example, when a tungsten lamp is used as a light source, the long wavelength component is wasted. Moreover, long wavelength light such as a semiconductor laser cannot be used as a light source.

Therefore, the usable wavelength range is limited, and it cannot be used for many purposes.

Additionally, in general, in photoreceptors, a carrier transporting substance that is effective against a specific carrier-generating substance is not necessarily effective against other carrier-generating substances, and It cannot be said that a carrier-generating substance that is effective against other carrier-transporting substances is also effective against other carrier-transporting substances. If the combination of these two substances is inappropriate, the electrophotographic sensitivity will not only decrease, but also the discharge efficiency will be poor especially in low electric fields, so the so-called residual potential will increase.
In the worst case, potential accumulates each time it is used repeatedly, making it practically unusable for electrophotographic purposes.

In this way, it is thought that there is no lawful means of selecting a suitable combination of the constituent substances of the carrier generation phase and the constituent substances of the carrier transport layer, and an advantageous combination is determined practically from among many substance groups. There is a need to.

By the way, known photoreceptors using organic photoconductive substances are generally used for negative charging.

The reason for this is that when negatively charged, the mobility of holes among carriers is high, which is advantageous in terms of photosensitivity and the like.

However, it has been found that using such negative charging causes the following problems. That is, the first problem is that ozone is likely to be generated in the atmosphere when negatively charged by the charger, worsening the environmental conditions. Another problem is that positive polarity toner is required for development of negatively charged photoreceptors, but positive polarity toner is difficult to manufacture due to the frictional electrification series for ferromagnetic carrier particles. .

Therefore, it has been proposed to use a positively charged photoreceptor using an organic photoconductive substance. For example, in the case of a positively charging photoreceptor in which a carrier transport layer is laminated on a carrier generation layer, and the carrier transport layer is formed of a material with high electron transport ability,
Trinitrofluorenone or the like is contained in the carrier transport layer, but this substance is unsuitable because it is carcinogenic.

On the other hand, a photoreceptor for positive charging may be considered in which a carrier generation layer is laminated on a carrier transport layer with a large hole transport ability.
In this case, since the carrier generation layer is present on the surface side, the printing durability and the like deteriorate, and this is not a practical layer structure.

In addition, as a photoreceptor for positive charging, U.S. Patent No. 361541
Specification No. 4 discloses a material containing a thiapyrylium salt (carrier generating substance) so as to form a eutectic complex with polycarbonate (binder resin). However, this known photoreceptor has disadvantages in that memory development is large and ghosts are likely to occur. US Patent No. 33
No. 57989 also discloses a photoreceptor containing phthalocyanine, but the characteristics of phthalocyanine change depending on the crystal type, and it is necessary to strictly control the crystal type. It is not suitable for copying machines that use a light source in the visible light wavelength range because of the insufficient amount of light and the large memory phenomenon.

Due to the above-mentioned circumstances, conventionally, it has been difficult to use a photoreceptor using an organic photoconductive substance for positive charging, and for this reason, it has been used mostly for negative charging.

On the other hand, many conventional electrophotographic photoreceptors have the disadvantage that the photosensitive layer suffers severe electrical fatigue when subjected to repeated electrophotographic processes, resulting in a very short service life. That is, in this type of photosensitive layer, although it is necessary to eliminate the charge in the photosensitive layer when one electrophotographic process is completed and the photosensitive layer is used for the next electrophotographic process,
Because the discharge rate at the end of the discharge is extremely slow, it is impossible to completely eliminate the charge even if the charge is removed by exposure to a large amount of light, and a high residual potential remains, and this residual potential repeats the electrophotographic process. Eventually, after a small number of continuous copies, the residual potential exceeds its permissible limit and becomes unusable as an electrophotographic photoreceptor.

It is possible to restore some types of photoreceptors to a usable state, but in order to restore them,
It is necessary to leave the photoreceptor in a rest state for a long time or to perform appropriate heat treatment, and it is not possible to restore the residual potential to a sufficiently low state, so the next step is to The number of consecutive copies possible before becoming unusable is greatly reduced.

For example, in an electrophotographic photoreceptor that uses a carrier-transporting substance with electron-donating properties and combines this with a carrier-generating substance, a small amount of A method has been proposed in which a Lewis acid of 100% is added to the layer containing the carrier transport material. However, although this method is effective for photoreceptors using specific electron-donating carrier transport materials,
Photoreceptors using many other electron-donating carrier-transporting materials are unable to sufficiently prevent the accumulation of residual potential. In particular, in the case of a photoreceptor using a carrier transporting material such as a polyarylalkane-based aromatic amino compound, it is difficult to obtain practical repeatability characteristics because of the large deterioration caused by ultraviolet rays and the like.

In addition, the types of charge transport materials that make up the photosensitive layer include:
For example, amine derivatives (Japanese Patent Application No. 56-8044) have been proposed. Although amine derivatives have various advantages, it has been found that they still contain problems that need to be improved. That is, when using an amine derivative alone as a CTM, if the tail of the discharge curve is not sufficiently cut, the sensitivity in the low electric field region is likely to be low, and the stability against ultraviolet light is insufficient, resulting in Since the sensitivity tends to decrease due to irradiation, the photoreceptor is likely to deteriorate due to ultraviolet light components when the copying machine is maintained under fluorescent lamps or sunlight.

3. Object of the invention The object of the invention is to have a material suitable for positive charging, stable against heat and light, 1, high carrier generation efficiency, and excellent photoconductivity even in a wide wavelength range. Furthermore, in combination with a specific carrier transport substance, the potential history state is maintained stably even during repeated use, reducing memory phenomena, stabilizing residual potential, and improving printing durability, resulting in consistently good visible images. An object of the present invention is to provide a photoreceptor that can form a photoreceptor.

Another object of the present invention is to have a very long service life with almost no electrical fatigue and a particularly long continuous service life, and to reduce the residual potential of the photosensitive layer to an extremely low level without causing any practical problems by eliminating static electricity. Therefore, continuous copying can be performed many times without performing a recovery operation, and the photosensitive layer is stable against oxidizing active species generated by light, temperature, and corona discharge. Another object of the present invention is to provide a positive charging photoreceptor that has high mechanical strength and can stably perform its functions over a long period of time.

4. Structure of the invention and its effects, that is, the photoreceptor according to the invention has a photosensitive layer consisting of a carrier generation phase and a carrier transport phase, and has a bisazo compound represented by the following general formula (1) as a main component. Carrier-generating substance 751 binder-resin! Oo 20 to 4 parts by weight
A carrier transport substance contained in the carrier generation phase in an amount of 0 parts by weight and containing at least one of a styryl compound represented by the following general formula (It) and an amine derivative represented by the following general formula (1111) as a binder is The photoreceptor for positive charging is characterized in that the carrier transporting phase contains the carrier transport phase in an amount of 30 to 150 parts by weight based on 10 weight parts of the resin.

General formula [I]: (However, in this general formula, A is Z: a group of atoms necessary to constitute a substituted or unsubstituted aromatic carbocycle or a substituted or unsubstituted aromatic heterocycle, Y: a hydrogen atom , hydroxyl group, carboxyl group or ester group thereof, sulfo group, substituted or unsubstituted carbamoyl group, or substituted or unsubstituted sulfamoyl group, RI: hydrogen atom, substituted or unsubstituted alkyl group, substituted or unsubstituted amino group, substituted or unsubstituted carbamoyl group, carboxyl group or ester group thereof, or cyano group, Ar: substituted or unsubstituted aryl group, R2: substituted or unsubstituted alkyl group, substituted or unsubstituted aralkyl group, or (Represents a substituted or unsubstituted aryl group.) General formula [■]: (However, R3 and R4 are mutually the same or different groups consisting of a substituted or unsubstituted alkyl group or phenyl group; phenyl group, naphthyl group,
W represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group or an alkylamino group. ) General formula [■]: (However, in this general formula, Ar2, Ar3: substituted or unsubstituted phenyl group,
Ar': represents a substituted or unsubstituted phenyl group, naphthyl group, anthryl group, fluorenyl group or heterocyclic group. ) In the present invention, the above-mentioned "phase" includes not only the case where the material forms a so-called layer, but also the case where the constituent materials form a phase in which they are in contact with each other.

According to the present invention, as is clear from the description of the examples described below, it is stable against heat and light, has excellent properties such as HP, charge retention ability, sensitivity, and residual potential, and can be used repeatedly. In some cases, it is possible to provide a positively charging photoreceptor that exhibits less fatigue change and has greater durability. In particular, in the present invention, taking advantage of the fact that the bisazo compound represented by the above general formula (1) has an excellent carrier generation ability,
By combining this with the carrier transport substance of general formula [11] to form a functionally separated photosensitive layer, a positively charging photoreceptor with even more excellent characteristics can be obtained.

Among the bisazo compounds represented by the above general formula (1), carbazole group-containing bisazo compounds represented by the following general formula [white] are particularly effective.

General formula [White: R"R"(R", R1t is an alkyl group, alkoxy group, or aryl group, R12, R", R14, R16, R17 is a hydrogen atom, a halogen atom, an alkyl group , alkoxy group, amino group, hydroxyl group, and aryl group) The bisazo compound of general formula (1) is thought to have a carbazole group in its molecule that contributes to the sensitizing effect, especially in the long wavelength region. However, in combination with the carbamoyl group moiety within the same molecule, it effectively acts as a coupler and exhibits good sensitivity characteristics over a wide wavelength range.
It also shows excellent properties as a photoreceptor for semiconductor lasers.

In the styryl compound of the above general formula [11], R3 and R4 are substituted (substituents are, for example, alkyl groups, alkoxy groups, phenyl groups) or unsubstituted alkyl groups (particularly those having 1 to 40 carbon atoms), or phenyl groups. The same or different groups consisting of
phenyl group) or unsubstituted phenyl group, naphthyl group, annyl group, fluorenyl group or heterocyclic group (eg N.

Preferably 5- to 7-membered rings containing 0 and/or S, and furthermore, these 5- to 7-membered rings may be bonded to other heterocyclic groups or hydrocarbon groups, and may be saturated or unsaturated. It can be either. ); R6 is a hydrogen atom, a halogen atom, an alkyl group (especially 1 to 40 carbon atoms), an alkoxy group (especially 1 to 40 carbon atoms), or an alkylamino group (alkyl group); In particular, the number of carbon atoms is 1 to 10), which are the same or different from each other. In addition, as a substituent of said substituted group, a C1-C40 alkyl group and an alkoxy group are mentioned.

In addition, in the amine derivative of the above general formula (Il[], a halogen atom, an alkyl group, a nitro group, an alkoxy group, etc. are used as substituents for Ar'' and Ar', and as a substituent for Ar', an alkyl group, Alkoxy groups, halogen atoms, hydroxyl groups, aryloxy groups, aryl groups, amino groups, nitro groups, piperidino groups, morpholino groups, naphthyl groups, anthryl groups, substituted amino groups, etc. are used. However,
An acyl group, an alkyl group, an aryl group, an aralkyl group, etc. are used as a substituent for the substituted amino group.

Further, in the photoreceptor according to the present invention, the carrier generating substance is added to the binder resin in a specific range such that carrier generating substance/binder resin = 20 to 40% (i.e., 20 to 40 parts by weight per 100 parts by weight of the binder resin). Since it is contained, it is possible to provide a positive band photoreceptor with less reduction in residual potential and acceptance potential. Outside the above range, if the amount of the carrier-generating substance is too small, the photosensitivity will be poor and the residual potential will increase too much, while if it is too large, the acceptance potential will drop too much. In addition, the content of carrier transport substance is also very important, carrier transport substance/binder resin = 30 to 150% (i.e., 30 to 150 parts by weight for 100 parts by weight of binder resin).
Within this range, the residual potential is low and the photosensitivity is good, and the solvent solubility of the carrier transport substance is also maintained well. Outside this range, if the amount of the carrier transport substance is small, the residual potential and photosensitivity will deteriorate, and if it is too large, the solvent solubility will be poor.

The carrier generating substance used in the present invention differs from the previously mentioned known substances in that it has the property of having little memory phenomenon and stabilizing residual potential.

In addition, the above-mentioned carrier-generating substance originally has a property that when a dispersion layer formed by dispersing it in a binder resin is charged and then exposed to light, the surface potential decays faster when it is negatively charged than when it is positively charged. It is something that you have. That is, the fact that light attenuation is fast when negatively charged means that the movement of electrons generated by light irradiation is faster and the rate of charge neutralization by holes is faster. On the other hand, the carrier transporting substance used in the present invention has the property of facilitating the movement of holes, and in combination with the properties of the carrier generating substance described above, it is possible to realize the use of positively charging photoreceptors. can.

For this purpose, it is desirable that the layer structure of the photoreceptor is as follows. That is, the photosensitive layer has a single-layer structure, and a carrier-generating substance is dispersed in the form of particles (as a pigment) in a layer in which a carrier-transporting substance is solidified with a binder resin.

In this case, the dispersibility of the carrier-generating substance is good;
It is also important that the shape is granular. tA,
Another layer structure includes a structure in which a second layer made of a carrier-generating substance solidified with a binder resin is formed on a first layer made of a carrier-transporting substance solidified with a binder resin. In this case, since photocarriers will be generated on the surface side, photosensitivity etc. will be even better, but in consideration of printing durability etc., it is desirable that the thickness of the second layer be 2 μm or more. .

Further, according to the present invention, by incorporating the above-mentioned styryl compound into the carrier transport phase, it is possible to greatly reduce the amount of change in residual potential during repeated use.
This is thought to be because styryl compounds also generate photocarriers when irradiated with light, and these photocarriers recombine trapped holes, or because styryl compounds preferentially absorb harmful light. It will be done.

In addition, if a polymer organic semiconductor having a fused aromatic ring or a heterocycle in a side chain is contained in the carrier transport phase, this polymer organic semiconductor has a property of generating photocarriers by absorbing ultraviolet light, Effectively contributes to photosensitization.
Therefore, the tail of the discharge curve becomes more sharp, and the sensitivity improves, especially in the low electric field region. As a result, in a conductive or insulating component development process, a good copy image without capri can be obtained without applying a bias voltage during the development stage. - When a bias voltage is applied in the component development process, the sharpness of the edge of the image decreases due to the so-called fringe phenomenon, causing blurring, but such problems are eliminated by the polymeric organic semiconductor. In addition, the polymeric organic semiconductor has high absorbance in the ultraviolet light region and absorbs most of the ultraviolet light, and has a kind of filter effect on ultraviolet light, thereby improving the ultraviolet light stability of the carrier transport phase. I can do it.

In the present invention, if an electron-accepting substance or a Lewis acid, which will be described later, is added to the photosensitive layer, a charge transfer complex is formed, so that the sensitizing effect can be further improved.

Next, as specific examples of the bisazo compound represented by the general formula [I] which is effective in the present invention, there may be mentioned, for example, those represented by the following structural formula. The bisazo compound is not limited.

(I-1) (1-2) (1-3) (1-4) (1-5) (I-6) 0σ1 (1-7) (1-9) Hs (1-10) (Toy 1 ) (1-12) (1-13) OCl (1-14) (1-16) (1-17) (t-is) (1-19) (1-20) (1-21) (1 -22) (1-23) (1-24) (1-27) (1-29) CH, c uniform (1'-33) (1-34) CH, CH3 (1-36) (1-37 ) (1-38) CI C1 (1-39) (1-40) (1-42) (1-43) (1-44) H,C As the styryl compound represented by the general formula (If), for example, Examples include those having the following structural formula.

(II-t) (If-2) (If-3) (M-4) (ns) (If-7) (II-8) (I[-9) (II-10) (If-11) (II-12) (…-14) (It-15) (It-16) (11-17) (II-18) (II-20) (II-21) (II-23) Cn-24> (II-25) (It-26) (II-28) (II-29) (…-31) (II-32) (II-33) (II-34) (It-35) (II-36) (1-37) (It-38) (It-39) (It-40) (n-41) (II-42) (II-43) (If-44) (1-45) (II-46) ([-47) (II-48) (11-49) (n-50) ([-51) (II-52) (If-53) (It-54) (II-55) (II-56) (…-57) (II-58) (II-59) (II-60) (…-61) (n-62) (1-64) (II-65) (1-68) (1-69) (II-71) (n-72) (II-73) (II-74) (II-75) (n-76) (It-77) (lI-78) (If-771,) (1-80) (1-81) (1-82) (1-84) (…-85) (1-86) (IF-88) (If-89) CH.

(II-90) (II-91) (fJ-92) (II-93) (1-94) (II-96) (IF-97) (...-98) (n-too) (It-101) (II-102) (II-103) (II-104) (11-105) (II-106) (II-108) (11-109) (II-110) (■-111) (I-112) (I-113) (II-114) tns (1-116) (II-117) (n-118) (If-120) (II-121) (I-122) (l-123) (If-124 ) (II-125) t (II-126) (II-127) ρI (1-128) 1 (It-129) (II-130) (u-x3x) (II-132) (n-133) ( [-134) (II-136) (II-137) (If-138) (II-139) (,:)Al (II-140) (II-141) () (II-142) (II-144 ) (IF-145) (It-146) (II-147) (II-148) (II-149) (1-150) (II-151) (...-152) (It-153) (II-154 ) (II-156) (II-157) (1-158) Furthermore, examples of the amine derivatives of the above general formula 1 include those having the following structural formula d,
It is not limited to these.

(G1) (It-2) (1-3) (III-4) (I[l-5) 0 toro) (III-7) (III-8) (1-9) (III-11) (■-1 game (1-13) (Ill-14),.

(DI-15) (ill-16) (III-17) (m-is) (III-19) (1-20) (Ill-21) (In-22) (II-23) (llll-24) (DI-25) (ll-26) (II-27) (m-28) (II-29) (Ill-30) (III-31) (In-32) (II-33) Also, in the present invention Examples of the above-mentioned polymeric organic semiconductors that can be used particularly in combination with the above-mentioned amine derivatives as a carrier transport substance include, but are not limited to, those illustrated below.

(mV-2) (IV-3) CH.

Ko CH.

(fV-10) (mV-11) (mV-12) (fV-x3) (fV-14) (mV-15) (mV-17) +-0-=CH-CH, CH.

(ILV-18) (IV-19) (mV-20) Among the above-mentioned polymeric organic semiconductors, poly-N-vinylcarbazole or its derivatives are highly effective and are preferably used. Such poly-N-vinylcarbazole derivatives mean that all or part of the carbazole ring in the repeating unit has various substituents, such as an alkyl group, a nitro group,
It is substituted with an amino group, a hydroxy group, or a halogen atom.

The above-mentioned bisazo compounds are, for example, the above (1-1)
The bisazo compound represented by can be synthesized, for example, by the method shown in the following synthesis example.

First, 2,7-sinitro-9-fluorenone and malonic acid nitrile were mixed by a known method (for example, J, 〇-rg, Ch
When the compound obtained by dehydration condensation (2゜7-sinitro-9-dicyanomethylidenefluorene) is reduced with tin and hydrochloric acid, 2,7- Diami2-9-dicyanomethylidenefluorene dihydrochloride was obtained. 3.31 g (o, o 1 mol) thereof was dispersed in $100 yd of salt, and the dispersion was cooled to a temperature of 5° C. while stirring, and 1.4 g of sodium nitrite was dissolved in 20-m water. The aqueous solution was added dropwise. After the dropwise addition was completed, stirring was continued under cooling for another 1 hour, and then filtration was performed. 10 g of ammonium hexafluorophosphate was added to the obtained filtrate, the resulting crystals were collected by filtration, and tetrazonium was dissolved in hexane. Fluorophosphate was obtained. This crystal was dissolved in 200% of N,N-dimethylformamide to obtain a dropwise solution for the next coupling reaction.

Next, 5.27 g (0.02 mol) of 2-hydroxy-3-naphthoic acid anilide (naphthol AS) was added to N
, Dissolved in 200-N-dimethylformamide, added 5.5 g of triethanolamine, cooled this solution to a temperature of 5°C, and added the above-mentioned dropwise solution dropwise to it while stirring vigorously. Ta. After the dropwise addition was completed, the mixture was stirred under cooling for 1 hour, and further stirred at room temperature for 2 hours, and the resulting crystals were collected by filtration. The crystals were washed twice with 1/(7) N,N-dimethylformamide and twice with 1/2 acetone and dried to give 6.70 g of a blue compound (yield: 8
3.0%).

This blue compound was targeted because in its infrared absorption spectrum, absorption due to the C=0 bond of the amide was observed at ν=1680, and the actual measured values of elemental analysis showed high consistency. It was confirmed to be compound (1-1). Further, the elemental analysis results (chemical formula is C5°H3°N, 04) were as follows.

Element CI-IN Actual value (%) 74.61 3.70 13.67 Theoretical value (H) 74.43 3.74 13.89 The photoreceptor of the present invention, e.g. In order to constitute the photosensitive layer of an electrophotographic photoreceptor, a layer in which the bisazo compound is dispersed in a binder resin may be provided on a conductive support. Alternatively, the bisazo compound may be used as a carrier generating substance, The general formula [11] and/or (I
In combination with a carrier transport substance of I[], a so-called functionally separated photosensitive layer of a laminated type or a dispersed type may be provided. In the composition of the photosensitive layer, not only one type of bisazo compound represented by the above general formula (1) but also a combination of two or more types can be used, and it can also be used in combination with other bisazo compounds or other carrier-generating substances. .

When the electrophotographic photoreceptor is of a functionally separated type, it is usually constructed as shown in FIGS. 1 to 3. The photosensitive layer 4 in FIG. 1 is formed by dispersing a carrier generating substance 7 made of the above-mentioned bisazo compound in a layer 6 containing the above-mentioned styryl compound and/or amine derivative (carrier transport substance) as a main component. This shows a structure in which the conductive support 1 is directly provided on the conductive support 1.

2 has a structure in which a photosensitive layer 4 similar to that in FIG. 1 is provided on a conductive support 1 with an intermediate layer 5 interposed therebetween.

The one in FIG. 3 generates a carrier with a thickness of 2 μm or more, which is obtained by dispersing the above-mentioned bisazo compound on the conductive support 1 into a layer 6 containing the above-mentioned styryl compound and/or amine derivative as a main component. The structure includes a photosensitive layer 4 made of a laminate of a layer 2 and a carrier transport layer 3 containing the above-mentioned styryl compound and/or amine derivative as a main component. In the configuration shown in FIG. 3, an intermediate layer 5 similar to the above may be provided between the conductive support 1 and the photosensitive layer 4.

When the above-mentioned bisazo compound is dispersed to form a photosensitive layer or a carrier generation layer, the bisazo compound is preferably made into powder with an average particle size of 5 μm or less, preferably 2 μm or less, and more preferably 1 μm or less. preferable. That is, if the particle size is too large, dispersion in the layer will be poor, and some of the particles will protrude from the surface, resulting in poor surface smoothness. In some cases, discharge may occur at the protruding parts of the particles, or toner may Particles tend to adhere and toner filming phenomenon occurs easily. The carrier generating material of the present invention is sensitive to long wavelength light (~700 nm).
Surface charges are neutralized by the generation of thermally excited carriers in the carrier-generating substance, and this neutralization effect is thought to be greater when the particle size of the carrier-generating substance is large. Therefore, high resistance and high sensitivity can only be achieved by reducing the particle size.

However, if the above particle size is too small, it tends to aggregate, which increases the resistance of the layer, increases crystal defects and reduces sensitivity and repeatability, or there is a limit to miniaturization. It is desirable to set the lower limit of OD to 1 μm.

The photosensitive layer can be provided by the following method.

That is, the above-mentioned bisazo compound is made into fine particles in a dispersion medium using a ball mill, a homomixer, etc., and a binder resin, a styryl compound and/or an amine derivative are added, and the obtained dispersion is coated.
When the particles are dispersed under the action of ultrasound in this method, uniform dispersion is possible.

Dispersion media used to form the layer include N, N-dimethylformamide, benzene, toluene, xylene,
, 2-dichloroethane, dichloromethane, tetrahydrofuran and the like.

When a binder resin is used to form the photosensitive layer, any binder resin can be used, but an electrically insulating film-forming polymer that is hydrophobic and has a high dielectric constant is particularly preferred. Examples of such polymers include, but are not limited to, the following:

a) Polycarbonate b) Polyester C) Methacrylic resin d) Acrylic resin e) Polyvinyl chloride f) Polyvinylidene chloride g) Polystyrene h) Polyvinyl acetate i) Styrene-butadiene copolymer j) Vinylidene chloride-acrylonitrile copolymer k) Vinyl chloride-vinyl acetate copolymer 1) Vinyl chloride-vinyl acetate-maleic anhydride copolymer m) Silicone resin n) Silicone-alkyd resin 0) Phenol-formaldehyde resin p) Styrene-
Alkyd resin q) Poly-N-vinylcarbazole r) Polyvinyl butyral These binder resins can be used alone or as a mixture of two or more. Further, the ratio of the carrier generating substance to the binder is 20% based on the present invention.
~40 parts by weight, carrier transport material is 30 parts by weight according to the invention
The amount is preferably 150 parts by weight (especially 50 to 120 parts by weight).

Furthermore, the photosensitive layer may contain one or more electron-accepting substances for the purpose of improving sensitivity, reducing residual potential or fatigue during repeated use, and the like. Examples of electron-accepting substances that can be used here include succinic anhydride, maleic anhydride, dibromaleic anhydride,
Phthalic anhydride, tetrachlorophthalic anhydride, tetrabromo phthalic anhydride, 3-nitro phthalic anhydride, 4-nitro phthalic anhydride, pyromellitic anhydride, meritic anhydride,
Tetracyanoethylene, Tetracyanoquinodimethane, 0
-Dinitrobenzene, m-dinitrobenzene, 1,3.
5-) Linitrone benzene, paranitrone benzonitrile, picryl chloride, quinone chlorimide, chloranil, brumanil, dichlorodicyanobarabenzoquinone, anthraquinone, dinitroanthraquinone, 9-fluorenylidene [dicyanomethylenemalonodinitrile],
Polynitro-9-fluorenylidene [dicyanomethylene malonodinitrile], picric acid, 〇-nitrobenzoic acid, p-nitrobenzoic acid, 3,5-dinitrobenzoic acid,
Pentafluorobenzoic acid, 5-nitrosalicylic acid, 3,
Examples include 5-dinitrosalicylic acid, phthalic acid, mellitic acid, and other compounds with high electron affinity.

The addition ratio of the electron-accepting substance is carrier-generating substance: two-electron-accepting substance = 1oo: o, ot
-200 preferably 100:0.1-100.

Note that the support 1 on which the photosensitive layer described above is to be provided is a metal plate,
A conductive thin layer made of a metal drum or a conductive polymer, a conductive compound such as indium oxide, or a metal such as aluminum, palladium, or gold is provided on a substrate such as paper or plastic film by means such as coating, vapor deposition, or lamination. A material consisting of: The intermediate layer that functions as an adhesive layer or barrier layer is made of a polymer such as the binder resin described above, an organic polymer material such as polyvinyl alcohol, ethyl cellulose, or carboxymethyl cellulose, or aluminum oxide. It will be done.

5. Examples Hereinafter, the present invention will be explained in more detail with reference to specific examples and comparative examples.

Vinyl chloride-vinyl acetate-
An intermediate layer having a thickness of 0.05 μm made of a maleic anhydride copolymer [S-LEC MF-10J (manufactured by Tanezu Kagaku Co., Ltd.) was formed. Next, each carrier generating substance, each carrier transporting substance, and a binder resin having a predetermined particle size shown in FIG.
A dispersion obtained by dispersing for 2 hours was applied onto the intermediate layer and dried to form a single-layer photosensitive layer, thereby producing each electrophotographic photoreceptor.

The electrophotographic photoreceptor thus obtained was tested using an electrostatic final tester "S".
P-428 type" (manufactured by Kawaguchi Denki Seisakusho), and the following characteristic tests were conducted. That is, a voltage of +6 KV is applied to the charger to charge the photosensitive layer by corona discharge for 5 seconds, and then the potential at this time is set to ■ for 5 seconds. ), then the amount of exposure necessary to attenuate the surface potential of the photosensitive layer to 172 by irradiating light from a tungsten lamp with the illumination intensity on the surface of the photosensitive layer being 351 ux,
That is, a half-reduced exposure amount E1/2 was set. In addition, the acceptance potential (2) at the time of charging by the above-mentioned corona discharge was measured at the initial stage and after 10,000 copies. In addition, the dark decay rate (VA-
■)/VrxlOO(%) and further initial potential ■ by -50
The exposure amount E 5 g (/ux·sec) required to attenuate from 0 (V) to −50 (V) was measured.

Furthermore, the sensitivity of semiconductor laser (7 gonm) was also shown (◎
A mark indicates very good quality, and an x mark indicates poor quality. ). The results are summarized in Figure 4. However, the carrier-generating substance and the carrier-transporting substance are indicated by the numbers of the structural formulas exemplified above.

According to this result, based on the present invention,
It can be seen that all of Arashi 10) exhibit significantly better electrophotographic characteristics than Rikku Sokki 1 to 4.

FIG. 5 shows a sensitivity curve a when a photoreceptor is constructed as in the same example using the bisazo compound according to the present invention (as shown in Example Arashi 2 in FIG. 4) as a carrier-generating substance. However, it can be seen that the photoreceptor according to the present invention exhibits excellent sensitivity even in a wide wavelength range, particularly in a long wavelength range such as a semiconductor laser range.

[Brief explanation of the drawing]

The drawings show embodiments of the present invention, and FIGS. 1, 2, and 3 are cross-sectional views of a portion of each side of an electrophotographic photoreceptor, and FIG. 4 is a cross-sectional view of each electrophotographic photoreceptor. FIG. 5 is a graph showing the photosensitivity due to carrier-generating substances. In addition, in the symbols shown in the drawings, 2...Carrier generation layer 3...Carrier transport layer 4...Photosensitive layer 5...Intermediate layer 6... ...A mixed layer of a carrier-generating substance and a carrier-transporting substance. Agent Patent Attorney Hiroshi Aisaka

Claims (1)

[Scope of Claims] 1. A carrier-generating substance having a photosensitive layer consisting of a carrier-generating phase and a carrier-transporting phase, the main component of which is a bisazo compound represented by the following general formula [1], is a binder resin 10.
The carrier generation phase contains at least one of a styryl compound represented by the following general formula [...] and an amine derivative represented by the following general formula 1 as a main component, and is contained in the carrier generation phase in a proportion of 20 to 40 parts by weight to 0 parts by weight. A photoreceptor for positive charging, wherein the carrier transporting substance is contained in the carrier transporting phase at a ratio of 30 to 150 parts by weight based on 100 parts by weight of the binder resin. General formula [1]: CN CN (However, in this general formula, ft2 ftm i2: substituted or unsubstituted aromatic carbon ring" 1 ft is the amount necessary to constitute a substituted or unsubstituted aromatic heterocycle) Atomic group, Y: hydrogen atom, hydroxyl group, carboxyl group or ester group thereof, sulfo group, substituted or unsubstituted carbamoyl group, or substituted or unsubstituted sulfamoyl group, R1 = hydrogen atom, substituted or unsubstituted alkyl group , substituted or unsubstituted amino group, substituted or unsubstituted carbamoyl group, carboxyl group or its ester group, or cyan group, Ar': substituted or unsubstituted aryl group, R2, substituted or unsubstituted alkyl group, substituted or represents an unsubstituted aralkyl group, or a substituted or unsubstituted aryl group.) General formula [■]: (However, R3 and the parent are mutually the same or different groups consisting of a substituted or unsubstituted alkyl group or phenyl group. ,
R5t; substituted or unsubstituted phenyl group, naphthyl group, anthryl group, fluorenyl group or heterocyclic group -
; W represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, or an alkylamino group. ) General formula [■]: (However, in this general formula, A r', A r'': substituted or unsubstituted phenyl group, Ar': substituted or unsubstituted phenyl group,
Represents a naphthyl group, anthryl group, fluorenyl group or a heterocyclic group. )