JPS5968749A - Electrophotographic receptor - Google Patents

Abstract

PURPOSE:To obtain a photoreceptor having excellent durability, high sensitivity and good flexibility at a low cost with ease of production by incorporating a specific stilbene compd. as a photoconductive material in a photosensitive layer. CONSTITUTION:A photosensitive layer 2 consisting of the compd. expressed by the formula [R<1> is H, alkyl, alkoxy or halogen, R<2>, R<3> are alkyl, (substd.) aralkyl, (substd.) allyl, R<4> is H, (substd.) phenyl], a sensitizer such as brilliant green, rhodamine B and a binder is formed on a conductive base 1. Alternately a photosensitive layer 2' consisting of an electric charge transfer layer 4 formed by dispersing a charge generating material 3 such as Se, Se-Te, azo pigment or the like in a soln. of a stilbene compd. and a binder is formed; otherwide, a charge generating layer 5 dispersed with the charge generating material 3 in the binder is formed, and the soln. of the stilbene compd. and the binder is coated on the layer 5 and is dried, whereby the photosensitive layer 2'' formed thereon with the layer 4 is formed.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a photoreceptor used in electrophotography,
Specifically, the present invention relates to an electrophotographic photoreceptor containing a specific stilbene compound in the photosensitive layer.

2. Description of the Related Art Electrophotography has been widely known as one of the image forming methods. "Electrophotography" generally means that a photoconductive photoreceptor is first charged in a dark place using, for example, corona II charging, and then imagewise exposed to selectively dissipate the charge only in the exposed areas to create an electrostatic charge. This is a method in which a latent image is obtained, and this latent image area is developed and visualized using electrostatic fine particles (toner) composed of a coloring material such as a dye or pigment and a binder such as a polymeric substance to form an image.

The basic patents required for a photoreceptor used in such electrophotography include: (1) being able to be charged to an appropriate potential in the dark; (21) having little charge dissipation in the dark; 3) Examples include scales that quickly dissipate charge when exposed to light q4.

Photoconductive materials used in the electrophotographic method include inorganic materials such as selenium, cadmium sulfide, and zinc oxide, but each of these conventional inorganic materials has many advantages. However, it also had various drawbacks and was not always satisfactory. . For example, selenium, which is currently widely used, is
) are fully satisfied, but the manufacturing conditions are difficult,
Manufacture] S1~ becomes high. Furthermore, since it does not have flexibility f1, it is better to process it into a bell shape than U, and it also has disadvantages such as being sensitive to heat and mechanical shock and requiring careful handling. be. Cadmium sulfide and zinc oxide are also used as photoreceptors by dispersing them in resin binders, but these photoreceptors have poor mechanical properties such as smoothness, hardness, tensile strength, and abrasion resistance, and cannot be used as they are. It cannot be used repeatedly.

-Recently, in order to eliminate the drawbacks of these inorganic materials, electrophotographic photoreceptors using various photoconductive organic materials have been proposed, and some of them have been put into practical use. For example, ゛, poly-N
A photoreceptor (%r [3rd
484237), a photoreceptor made by sensitizing poly-N-vinylcarbazole with a pyrylium salt-based color cord (
(described in Japanese Patent Publication No. 48-25658), a photoreceptor containing an organic pigment as a main component (described in Japanese Patent Application Laid-open No. 47-37543), a eutectic complex consisting of Dye F31 and a resin as a main component. A photoreceptor (described in Japanese Patent Application Laid-Open No. 47-10735), and the like. These photoreceptors have excellent properties and are considered to be relatively valuable in practical terms.
Considering the characteristics of 41) before it was developed as a photoreceptor for electrophotography, it is not fully satisfactory.

In general, the characteristics of a photoreceptor vary depending on the purpose or manufacturing method, but they largely depend on the photoconductive material used, so they must have sufficiently satisfactory characteristics as a photoreceptor for electrophotography. There is a strong need for a photoconductive monthly rate.

The present invention was also made in accordance with such requests.
As a result of extensive research and consideration by the present inventor, the following general formula (I) \ 3 where R1 is a hydrogen atom, an alkyl group, an al=]oxy group or a []gen atom, and R2 and R3 are an alkyl group, a substituted or an unsubstituted aralkyl group or a substituted or unsubstituted allyl group, R4 represents a hydrogen atom or a substituted or unsubstituted phenyl group.

It has been found that the stilbene compound represented by the following formula works effectively as a photoconductive substance for electrophotographic photoreceptors. Furthermore, it has been discovered that this stilbene compound can be used in combination with various materials to create photoreceptors with unexpected effects, as will be apparent from the description below. The present invention was completed based on these findings.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a photoreceptor that can overcome the various drawbacks of the conventional photoreceptor described above and fully satisfy the conditions required in electrophotography, and is particularly suitable for the photoreceptor. The object of the present invention is to provide a photoconductive material that has excellent properties. Another object of the present invention is to provide an electrophotographic photoreceptor that is easy to manufacture, relatively inexpensive, and has excellent durability.

That is, the present invention provides an electrophotographic photoreceptor in which a photosensitive layer is provided on a conductive support, and the photosensitive layer has the above general formula (
It is characterized by containing a stilbene compound represented by I).

The present invention will be explained in detail below with reference to the drawings. Figures 1 to 3 are three representative cross-sectional views of the photoreceptor according to the present invention, in which the numbers 1 are the conductive support, 2, 2' and 2'' are the photosensitive layers. , 3 represents a charge-generating substance, 4 represents a charge-transporting medium 6--or a charge-transporting layer, and 5 represents a charge-generating layer.

A triphenylphosphonium group represented by the general formula (I) (7e represents a halogen ion) used in the present invention or a dialkylphosphorous acid represented by PO (OR>2 (where R represents a lower alkyl group)) is a group] and the phenyl derivative represented by the following general formula (11[)[
In the formula, R1 is a hydrogen atom, an alkyl group, an alkoxy group, or a halogen atom, R2 and R3 are an alkyl group, a substituted or unsubstituted aralkyl group, or a substituted or unsubstituted allyl group, and R4 is a hydrogen atom or a substituted or unsubstituted allyl group. Represents a substituted phenyl group] It can be obtained by reacting with a carbonyl compound represented by the following.

A specific example of the stilbene compound represented by the general formula (I) obtained in this way is illustrated below in Example 1.

Table 1 3 3-CH34-CH2℃-GHz ((large) 1" 4
,,2-C2Hs 4 -CI-12 -〇)-1
Second m3-021-1! , 4
-CH2 -CH2((Σ〉1-
1 divination 6 2-Cλ 4
-CI-12-@) -CI-12-4
Cabinet〉To193-OCH34-C112-□ -CI-
12tsu l-1102-〇C2Hs 4 -Ct-1
2 ◇ -CI-12 1” 11 H4C
21-Is C2R15to112 H4-CH2((U〉-CH3-0
f-hGcl-L3 To1 substitution position 18 H4-C)-b((VCI C82GG℃
1] Substitution position a] Substitution position 3G 3-CI-(34-CH20C2H5-CI-
12-<four>←C2H5to13720C2H54Cl
-12((VCH3-CI-l 2()CI-1311
401-12-Cth()C1h-CI-12()
CI-h H41l-13-CI-12()OCl-
h -CI-12■0CI-+3 l-1421-1
4-CI-13-CI-12-(La 1-143
l-14--C2H5-CH2-(La 1"44
I 4 - (C
H2) 2 Cl-13-CH2 ((macro)-0Cl
-131-145H4-(CI-12) 3 CH3-
CI-12 H substitution position Ihi 13- Substitution position 59 H2-Chh
-CI-+2←@-i: Cf-h H60H3
-CI-1:l -CH20C2-h I''61
H'4 (℃H 62H4%c+-+a (death C1''3 l-1
65H4+CH(CH3)CH3-Gukugi〉-CH(C
H3)Cl-13H66H4knowledge+cI-12)3C1-
13 (To1-1su3CH3H67H4■C (CH3)
3 Light C (C113) 3 H68H4℃ (瀘C
H3H 14- Substitution position 74 H2 [Phase] [Phase] H771-12
-4 瀘CH3(■C1-I 3H78H2+0CH3(
XOCl-h l-180H2-CH3 1” Substitution position 82 H2-CH3 (column 0Chh H83L-13
-@) @
185 1-1 3 +OCH
3+0Chh H90H4+0C2Hs +0C
2H1H substitution position I 100 H44 is c℃ (U 1) 17-112 l-14-C1-(3(■C1-h H
18- Substitution position a)・116 H4-CH3(■0Cl-h H117H
, 4CH3(■0C21-151-l" 119 H4-CH30N(C2H5)2 +12
0 H4-CI-13+cβ 1''121H4'
C2Hs J
E-Σ) l-112
2H4-021-15+Clh l-11241-
(4C2H5+02 day 5 1 substitution position 127 l'4 C2H5+0C2Hs H
128Fl 4
C2H5% huge〉-N (CI-13) 2
1-1129 8 4
021-15
((Minister)-C1l-11321-l
4-(CI-12)2C1-+
3 ←gu〈5〉-〇〇H31-1133+
-14-(CI-1 mountain CH3℃ H134H4-(C
I-1 mountain Cl-13+N (CI-h) 2t-1135l
-14-(CH2)3CH3+cl-h l-1 substitution position 138 H'4-(CI-1 mountain CHB and N (C
I-13) 2 +-139H2-CI-13 CH3
t-1 40H3-CI-h [Phase] H411'''
l -CI-12 [Phase] [Phase] H4n
H4-CHbe)o CH3-@t H45,
H4-Ct-12+0CR3%■ H,4G)1
4 -C)lzeOc2)-1s <◇H
21- Substitution position X◇ 156 11 4
-CH3-CI-13(D 157 H4C2H5-C2Hs 22- The photoreceptor of the present invention has a photosensitive layer containing one or more of the above-mentioned stilbene compounds. Figure 1, Figure 2
It can be used as shown in FIG.

The photoreceptor shown in FIG. 1 has a photosensitive layer 2 comprising a stilbene compound, a sensitizing dye, and a binder (binder resin) on a conductive support 1. The photoreceptor shown in FIG. The stilbene compound here acts as a photoconductive substance, and the generation and transfer of charge carriers necessary for light attenuation take place via the stilbene compound. However, the stilbene compound has almost no absorption in the visible region of light, so in order to form an image with visible light, it is necessary to sensitize it by adding a sensitizing dye that absorbs in the visible region. be.

The photosensitive member shown in FIG. 2 has a photosensitive layer 2' provided on a conductive support 1, in which a charge generating substance 3 is dispersed in a charge transporting medium 4 made of a stilbene compound and a binder. The stilbene compound here together with the binder (or binder and plasticizer) forms the charge transport medium 4, while the charge generating substance 3 (a charge generating substance such as an inorganic or organic pigment) generates the charge carriers. In this case, the charge transport medium 4 is mainly responsible for receiving charge carriers generated by the charge generating substance 3 and transporting them. In this photoreceptor, the basic condition is that the absorption wavelength regions of the charge generating substance 3 and the stilbene compound do not overlap each other, mainly in the visible region. This is because in order to efficiently generate charge carriers in the charge generation material 3, it is necessary to transmit light to the surface of the charge generation material. The stilbene compound represented by the general formula (I) has almost no absorption in the visible region, and when combined with a charge generating substance 3 that generally absorbs light in the visible region and generates charge carriers, it is particularly effective as a charge transport substance. Its characteristic is that it works.

The photoreceptor shown in FIG. 3 has a photosensitive layer 2'' formed of a laminated layer of a charge generation layer 5 mainly composed of a charge generation substance 3 and a charge transport layer 4 containing a stilbene compound on a conductive support 1. In this photoreceptor, the charge transport layer 4
The light transmitted through reaches the charge generation layer 5, and charge carriers are generated in that region.On the other hand, the charge transport PVj/I receives charge carrier injection and transports it, which is necessary for light attenuation. The generation of charge carriers is carried out in the charge generation substance 3,
Further, charge carriers are transported in the charge transport layer 4 (mainly a stilbene compound acts). These mechanisms are the second
This is the same as the explanation given for the photoreceptor shown in the figure.

In order to actually produce the photoreceptor of the present invention, in the case of the photoreceptor shown in Figure 1, one or more stilbene compounds are dissolved in a solution containing a binder, and then a sensitizing agent The photosensitive layer 2 may be formed by preparing a liquid containing the above ingredients, applying it onto the conductive support 1, and drying it.

The thickness of the photosensitive layer 2 is 3 to 50 μm, preferably 5 to 20 μm.
m is appropriate. The amount of the stilbene compound in the photosensitive layer 2 is 30 to 70% by weight, preferably about 50% by weight, and the amount of the sensitizing agent in the photosensitive layer 2 is 0.1 to 5% by weight. Preferably 0.5~
It is 3% by weight. For enhanced r1, triarylmethane dyes such as Brilliant Green, Victoria Blue 81 Methyl Violet, Crystal Violet, Acid Violet 6B, Rhodamine 810-Damine 6G, Rhodamine G Extra, Eosin S11 Ritrosin, Rose Bengal, Xanthine dyes such as full 1st Ruin, thiazine dyes such as medilene blue, cyanine dyes such as cyanine, 2,6-diphenyl-4
-(N,N-dimedylaminophenyl)thiapyrylium verchlorate, benzobyrylium salt (equity Ill 4
8-25658)) and other biryllium dyes 1'
11 etc. are mentioned. Note that these sensitizing agents may be used alone or in combination of two or more.

In addition, in order to produce the photoreceptor shown in FIG. 2, fine particles of the charge generating substance 3 are dispersed in a solution containing one or more stilbene compounds and a binder, and this is made into a conductive material. The photosensitive layer 2- may be formed by coating it on the support 1 and drying it.

The thickness of the photosensitive layer 2' is 3 to 5 μm, preferably 5 to 20 μm.
m is appropriate. The amount of stilbene compound fabric in the photosensitive layer 2' is 10 to 95% by weight, preferably 30 to 90,000% by weight.
The charge generating substance 3 accounts for 0.1 to 50% by weight, preferably 1 to 20% by weight in the photosensitive layer 2-.

Examples of the charge generating substance 3 include inorganic pigments such as selenium, telluride, cadmium sulfide, cadmium-selenium sulfide, and α-silicon; examples of organic pigments include CI Pigmen 1 to Blue 25 (color index CI
21180), Seeia Pigment Red 41 (
CI 21200), Sea Eye Acid Red 52
(CI 45100), CI Basic Red 3 (CI 45210), Azo Face 1 having a revazole bone core (described in JP-A-53-95033), Azo Pigment having a distyrylbenzene bone core (JP-A-53-95033) Azo face with triphenylamine bone core ¥31 (described in Japanese Patent Application Laid-Open No. 53-132)
347), an azo pigment having a dibenzothiophene bone core (described in JP-A-54-21728),
Azo pigment with ochlydiazole bone core
-12742), azo pigments having fluorenone cores (described in JP-A-54-22834),
13+ (described in JP-A-54-17733), azo-pigment with distyryloxadiazole bone core (JP-A-54-2129)
Azo pigments such as azo pigments having a disdyrylic rubazole core (described in JP-A-511-14967), such as C.I. Pigment Blue 16 (
Phthalocyanine pigments such as CI 74100), such as Sea Eye Butt Brown 5 (CI 73410),
Indigo pigments such as Sea Ibara 1-Dye (CT 73030), Argo Scarlet B (manufactured by Bayer)
, and perylene pigments such as Indus Strene Scarlet 1 to R (manufactured by Bayer AG). Note that these charge generating substances may be used alone or in combination of two or more types.

Furthermore, in order to produce the photoreceptor shown in FIG. 3, a charge-generating substance is vacuum-deposited on a conductive support 1, or fine particles 3 of a charge-generating substance are deposited in a suitable solvent in which a binder is dissolved if necessary. The charge generation layer 5 is formed by coating and drying the dispersion, and if necessary, performing surface finishing and film thickness adjustment by methods such as puff polishing, and then forming a charge generation layer 5 on which one or two types of dispersions are applied. The charge transport layer 4 may be formed by coating a solution containing at least one stilbene compound and a binder and drying it. The charge generating material 3 used to form the charge generating layer 5 here is the same as that used in the description of the photosensitive layer 2- above.

The thickness of the charge generation layer 5 is 5I1m or less, preferably 2μm.
The appropriate thickness of the charge transport layer 4 is 3 to 50 μm, preferably 5 to 20 μm. If the charge generation layer 5 is of a type in which fine particles 3 of the charge generation substance are dispersed in a binder, the proportion of the fine particles of the charge generation substance 3 in the charge generation layer 5 is 10 to 95% by weight. , preferably about 50 to 90% by weight. Further, the proportion of the stilbene compound in the charge transport layer 4 is 10 to 95%, preferably 30 to 90%.
Weight%.

In the production of any of these photoreceptors, a metal plate or foil made of aluminum or the like, a plastic film deposited with a metal such as aluminum, or paper treated with electrical conductivity is used as the conductive support 1. Also,
As the binder, condensation resins such as polyamide, polyurethane, polyester, epoxy resin, polyketone, and polycarbonate, and vinyl polymers such as polyvinyl ketone, polystyrene, and poly-N-vinylcarbazole polyacrylamide are used. Any insulating and adhesive resin can be used. A plasticizer may be added to the binder if necessary, and examples of such plasticizers include halogenated paraffins, polychlorinated biphenyls, dimedylnaphthalene, and dibutylphthalene.

30-Furthermore, the photoreceptor obtained in the following manner may have an adhesive layer or a paris ψ between the conductive support and the photosensitive layer, if necessary.
layers can be established. Materials used for these layers include polyamide, 21-cellulose, aluminum oxide, etc., and the film thickness is preferably 1 μm or less.

To make a copy using the photoreceptor of the present invention, the photoreceptor surface is charged and exposed, then developed, and if necessary, copied onto paper or the like. The photoreceptor of the present invention obtained as described above has excellent advantages as an electrophotographic photoreceptor, such as high sensitivity and flexibility.

Examples are shown below. In the following examples, all the parts are small hanging parts.

Example 1 0.96 g of 60% sodium hydride lx was dispersed in ethylene glycol dimethyl ether at 20 m°C, and 5.4 g of dimethyl p-1-xybenzyl 71-sulfonate was added to this.
4 (] (00,020 mol) was added at room temperature.Additionally 4-N,N-diphenylaminobenzaldehyde5.
A solution of 470 (0,020 mol) in N,N-dimethylformamide at 25 m°C was added, and the reaction was carried out at room temperature for 6 hours.

The reaction mixture was poured into about 300 mj2 of water, and the resulting yellow precipitate was collected by filtration, washed with water, and dried. The yield was 6.53 g (yield 83.4%).

Recrystallization from cyclohexane gave pale yellow cap-shaped crystals of 4-4''-(N,N-diphenylamino)stilbene (NO, 61 in Table 1).The melting point was 168. The temperature was .5 to 170.0°C.

As a charge generating substance, 1260 parts of a 2% tetrahydrone furan solution of Diane Blue (CI Pigment Blue 25, CI 21180>711+, polyester resin (Vylon 200, manufactured by Toyobo Co., Ltd.) and 3100 parts of tetrahydrofuran were pulverized and mixed in a ball mill. The resulting charge generation layer forming liquid was applied using a doctor blade onto the aluminum surface of a conductive support made of a polyester base coated with aluminum vapor, and air-dried to form a charge generation layer with a thickness of about 1 μm.

On the other hand, electricity? As the i7i transport substance, 2 parts of 4-ethoxy-4'-(N, N-diphenylamino)stilbene (No. 61 in Table 1) obtained above, polycarbonate resin (1300 for Panlite, manufactured by Teijin Ltd.) After mixing and dissolving 2 parts and 16 parts of tetrahydrofuran to prepare a charge transport layer forming liquid, this was applied onto the charge generating layer using a doctor blade, and heated at 80°C for 2 minutes, then for 10 minutes.
A charge transport layer having a thickness of about 20 μm was formed by drying at 5° C. for 5 minutes to prepare photoreceptor No. 1.

Examples 2 to 10 Photoreceptors Nos. 2 to 10 were prepared in exactly the same manner as in Example 1, except that the charge generating substance J: and the charge transporting substance (stilbene compound) were replaced with those shown in Table 2.

-33=34- Example 11 On an aluminum plate having a thickness of about 300 μm, selenium was vacuum-deposited to a thickness of about 1 μm to form a charge generation layer. Next, 2 parts of a stilbene compound of NO,1, a polyester resin (Polyester Adhesive 4900 manufactured by DuPont)
0) Mix 3 parts and 45 parts of tetrahydrofuran,
Dissolve to create a charge transport layer forming liquid, apply this onto the charge generation layer (selenium vapor deposited layer) using a doctor blade, air dry, and then dry under reduced pressure to a thickness of about 12 cm.
The photoreceptor N0 of the present invention is formed by forming a charge transport layer of μm.
．． I got 11.

Example 12 A charge generation layer (however, the thickness is about 0.3 μm) was formed using periphery represented by the following structural formula instead of selenium, and a stilbene compound of No. 62 was used instead of NO.1. Photoreceptor No. 12 was prepared in exactly the same manner as in Example 11 except that the photoreceptor No. 12 was used.

Example 13 A mixture of 1 part of Diane Blue (same as used in Example 1) and 158 parts of Te]herahydrofuran was ground and mixed in a ball mill, and to this was added 12 parts of stilbene compound No. 61, and polyester. Add 18 parts of resin (Polyester Adhesive 49000 manufactured by Decobon Co., Ltd. and further mix) 51 Photosensitive layer forming liquid was applied onto the aluminum-deposited polyester film using a doctor blade, and dried at 100°C for 30 minutes. Thickness approx. 13
Photoreceptor No. 1 of the present invention is formed by forming a photoreceptor layer of μm.
3 was created.

Photoreceptors Nos. 1 to 13 thus produced were tested using a commercially available electrostatic copying paper tester (5P manufactured by KK Kawayo Rai Ia Seisakusho).
428 type) for 20 seconds to charge it with a corona discharge of 16 KV or +6 KV, leave it in a dark place for 20 seconds, measure the 37- surface potential Vl)o (volts) at that time, and then Irradiate the photoreceptor surface with lamp light so that the illumination intensity is 20 lux, find the time (seconds) until the surface potential becomes 1/2 of V Do, and calculate the exposure amount E1/2 (lux seconds). did.

The results are shown in Table 3.

In addition, after each of the photoreceptors described above is charged using a commercially available electrophotographic copying machine, light is irradiated through the original image to form an electrostatic latent image, which is developed using a dry developer. When the resulting image (toner image) was statically transferred and fixed onto plain paper, a clear transferred image was obtained. A similarly clear transferred image was obtained when a wet developer was used as the developer.

38- Table 3 Photoreceptor V Do E 1/2NO
1 (volt) (lux seconds) 1 -13
29 1.8 2 -1084 2.4 3 -1192 2.7 4 -824 1.5 5 -1123 2.6 6 -992 3.0 7 -1133 1.2 8 -1051 2.5 9 -1166 0 .9 10 -1006 3.611 -9
27 5.0 12 -1204 6.613
+612 4.6

[Brief explanation of the drawing]

1, 2, and 3 are cross-sectional views enlarged in the thickness direction of an electrophotographic photoreceptor according to the present invention. 1... Conductive support 2.2-12''... Photosensitive layer 3... Charge generating substance 4... Charge transporting medium or charge transporting layer 5... Charge generating layer Patent applicant Ri Co., Ltd. −1− Representative Patent Attorney Hidetake Komatsu
Name (674) Stock suit Ricoh 4, Agent 5, Date of amendment order (voluntary) 6, Details subject to amendment m, Column 7 for detailed explanation of the invention, Contents of amendment 1- (1) Details 3 lines from the bottom of page 5 of the book, ``Headed.'' and [
Furthermore, insert the following sentence between...]. "Substituents for the aralkyl group or allyl group in R2 or R3 of general formula (I), or the phenyl group in R4 include lower alkyl groups, lower alkoxy groups, lower dialkylamimes, halogen atoms, etc." (2) ) In the 7th line from the bottom of page 27, "C.I. Pigment..." is corrected to "C.I. Pigment...". 2-386-

Claims (1)

[Scope of Claims] A photoreceptor for electrophotography, characterized in that a photosensitive layer containing as an active ingredient at least one stilbene compound represented by the following general formula (I) is provided on a conductive support. \3 However, R' is a hydrogen atom, an alkyl group, an alkoxy group, or a halogen atom, R2 and R3 are an alkyl group, a substituted or unsubstituted aralkyl group, or a substituted or unsubstituted allyl group, and R4 is a hydrogen atom or a substituted or unsubstituted allyl group. Represents a substituted phenyl group.