Electrophotographic sensitive body

[Detailed Description of the Invention]

[Industrial Application] The present invention relates to an electrophotographic photoreceptor and relates to the electrophotographic photoreceptor which has a low-molecular organic photo conductor which gives the electrophotographic properties improved in detail. [Description of the Prior Art] the photosensitive layer of a former and electrophotographic object -- inorganic light conductive materials, such as selenium, a zinc oxide, and a cadmium sulfide, -- extensive (although used, research using an organic light conductive material as an electrophotographic photoreceptor has been done actively in recent years.) As the fundamental characteristic required of an electrophotographic photoreceptor here, l) It is mentioned being charged in suitable potential by corona discharge etc. in a dark place, that the electrification maintenance rate in two dark places is good, discharging an electric charge promptly by irradiation of 3 light, that there is little rest potential after irradiation of 4 light, etc. - An organic system compound is lightweight compared with an inorganic system compound to boat fishing, and it excels in membrane formation nature and flexibility, and a manufacturing cost is also low, and also it has an advantage, like there is also no toxicity, and many electrophotographic photoreceptors using an organic compound have been proposed and put in practical use in recent years. Although various kinds of organic light-sensitive polymer including poly-N-vinylcarbazole has been proposed as a typical thing of the electrophotographic photoreceptor of an organic system, Although these polymer was excellent in respect of lightweight nature and membrane formation nature etc. compared with the inorganic light conductive material, since it was inferior compared with the inorganic system photoconducting material in respect of sensitivity, endurance, the stability by an environmental variation, mechanical strength, etc., utilization was difficult. The hydrazone compound of an indication in a U.S. Pat. No. 4150987 gazette etc., The low-molecular organic photo conductor of 9-styryl anthracene compound of a statement, etc. is proposed by a triallyl Pyrazoline compound given in a U.S. Pat. No. 3837851 gazette etc., JP,51-94828,A, JP,51-94829,A, etc. Although such a low-molecular organic photo conductor can cancel the fault of the membrane formation nature which had become a problem in the field of the organic light conductive polymer by choosing the binder to be used suitably, sufficient thing cannot say it in respect of sensitivity. Since it was such, the lamination structure which made the charge generating layer and the electric charge transportation layer carry out functional separation of the photosensitive layer in recent years was proposed. The electrophotographic photoreceptor which made this lamination structure the photosensitive layer can improve now in respect of the sensitivity to visible light, electric charge holding power, surface intensity, etc. As an electric charge transportation substance, many organic compounds are mentioned to this. For example, the Pyrazoline compound of JP,52-72231,A, the hydrazone compound of JP,55-52063,A, The stilbene compound of the Tripe nil amine compound of JP,57-195254,A, Provisional-Publication-No. No. 56119132 gazette, and JP,54-58445,A, JP,54-151955,A, and JP,58-198043,A, etc. are known. however -- the electrophotographic photoreceptor which used the conventional low-molecular organic compound for the electric charge transportation substance -- sensitivity and the characteristic -- also Absolutely(ing) -- it is not enough, and when repetition electrification and exposure are performed, there is a point which change of bright section potential and dark part potential should still improve greatly. [Problem(s) to be Solved by the Invention] The object of the present invention cancels various faults which the conventional photo conductor has, it is high sensitivity and providing the electrophotographic photoreceptor which was small excellent in endurance has potential change. Other objects of the present invention are easy to manufacture, and it is comparatively cheap, and it is in providing the new organic photo conductor excellent also in endurance. [Means for Solving the Problem] That is, in an electrophotographic photoreceptor which has a photosensitive layer on a conductive base material, the present invention is an electrophotographic photoreceptor, wherein the photosensitive layer contains p-terphenyl compound shown by following general formula (I). However, a benzene ring to which Ar1 and Ar2 may have a substitution machine is shown among a formula. As a substitution machine which Ar and Ar2 may have, they are alkoxy groups, such as Alkyl machine [, such as methyl, ethyl, propyl, and butyl, ], methoxy, and ethoxy , propoxy, and phenyl. Aryl groups, such as Naff Chill, are mentioned. Methyl, ethyl in which R may have halogen atoms, such as a hydrogen atom, fluoride, chlorine, and bromine, and a substitution machine. Alkoxy groups, such as Alkyl machines, such as propyl and butyl, or methoxy one, Nidoxi, and propoxy one, are shown. Although a reason p-terphenyl compound of the present invention shows high sensitivity and durable potential stability is not certain, a conjugated system is long and it thinks because it becomes advantageous for Scouring of compounds. According to these artificers' examination, as shown in a general formula [Ir] also among p-terphenyl compounds shown by a general formula (1), it is preferred to have at least one Alkyl machine or an alkoxy group in ArI and Ar2. Alkoxy groups, such as Si and propoxy one, are shown. m shows an integer of 1 or 2 and n shows O, I, or an integer of 2. Especially p-terphenyl compound of such structures shown by a general formula [■] also by striking shows the characteristic outstanding in sensitivity and the potential characteristic. ((However, R3 and R4 show a methyl group or a methoxy group among a formula.) However, the inside of a formula, and R1 and R2 methyl, ethyl.) The example of representation is given about a compound shown by general formula [I] in Alkyl machines, such as propyl, or methoxy one, and below Etki. <An example of a compound> CH30 It carries out and is 2r'II>. Next, a synthetic example of the compound is shown. (Example No of a compound, and (2) synthetic methods) It is 2.00 g (8, 12mmol) of 4-amino p-terphenyl to three Lofrasco of 200m I!, 5.31 g (24, 36mmo+) of p-iodine toluene, anhydrous potassium carbonate 8.96g (64, 96mmol), 2.0 g of copper powder, and nitrobenzene 30m1 were put in, and it was made to react under heating at reflux by a heating mantle for 5 hours. When a content was filtered after an end of a reaction and nitrobenzene was removed from Filtrate by distillation under reduced pressure, a crystal deposited. After washing the rough crystal with methanol, a silica gel column performs separation refining, and it is illustration compound lTh2. 1.40 g (40.6% of yield) was obtained. The melting point was 180.0degreeC~181.0degreeC. The ultimate analysis is as follows as C32H2 and N. 0% 8% N% calculated value 90.35 6.35 3.29 actual measurements 90.41 6.32 3.27 -- an infrared resonance spectrum (KBr tablet method) of this compound is shown in Drawing 1. It turns out that composition nature can compound p-terphenyl compound of the present invention easily cheaply as mentioned above. It is compounded by same technique also about compounds other than the composition side. In a desirable example of the present invention, p-terphenyl compound shown in an electric charge transportation substance which contains a photosensitive layer in a charge generating layer and an electric charge transportation layer at an electric charge transportation layer of an electrophotographic photoreceptor which carried out functional separation by the - General type can be used. As for an electric charge transportation layer by the present invention, it is preferred to apply solution made to dissolve a compound shown by the general formula and a binder in a suitable solvent, and to make it form by making it dry. As a binder used here, they are Boryey rate resin and polysulfone resin, for example, Polyamide resin, an acrylic resin, acrylonitrile resin, methacrylic resin, Vinyl chloride resin, polyvinyl acetate resin, phenol resin, an epoxy resin, Polyester resin, alkyd resin, polycarbonate, polyurethane or copolymer resin, for example, a styrene butadiene copolymer, a styrene acrylonitrile copolymer, a styrene maleic acid copolymer, etc. can be mentioned. Organic light conductive polymers, such as polyvinyl carbazole, polyvinyl anthracene, and polyvinyl pyrene, can also be used besides such insulating polymer. As for a combination rate of this binder and an electric charge transportation substance of the present invention, it is preferred to make an electric charge transportation substance into 10~500 weight per 100 weight sections of binders. It is electrically connected with a lower charge generating layer, and an electric charge transportation layer has a function in which these electric charge careers can be conveyed to the surface while receiving an electric charge career poured in from a charge generating layer under existence of an electric field. Under the present circumstances, this electric charge transportation layer may be laminated on a charge generating layer, and may be laminated on the bottom of it. However, as for an electric charge transportation layer, laminating on a charge generating layer is desirable. Since this electric charge transportation layer has the limit that an electric charge career can be conveyed, it cannot thicken film thickness more than needed. Generally, although it is 5 micrometers ~ 40 micrometers, a desirable range is 10 micrometers ~ 30 micrometers. As for an organic solvent used when forming such an electric charge transportation layer, it is preferred to choose from what changes with kinds of binder to be used or dissolves neither a charge generating layer nor lower bottom Stratification. As a concrete organic solvent, they are ketone, such as alcohols, such as methanol, Ethano, - Le, and an iso proper tool, acetone, methyl ethyl ketone, and cyclohexanone, and N. Amide, such as N-Dimethylpolm amide, N, and N-Dimethyl aceto amide Sulfo Xide, such as dimethyl sulfoxide, a tetrahydro franc, Ether, such as dioxane and ethylene glycol monomethyl ether, Ester, such as acetic acid methyl and ethyl acetate, chloroform, a methylene chloride, Aromatic series, such as fatty series halogenated hydrocarbon, such as dichloro ethylene, a carbon tetrachloride, and trichloroethylene, or benzene, toluene, xylene, mono-chlorobenzene, and dichlorobenzene, can be used. Coating can be performed using coating methods, such as an immersion coating method, a spray coating method, a spinner coating method, the Mayer Barko Tyng method, and a braid coating method. Method of dryness of carrying out drying by heating is preferred after set-to-touch [ in room temperature ]. Drying by heating is generally the time of the range of 5 minute~2 hours at temperature of 30 degrees C~200 degreeC, and it is preferred to carry out under stillness or ventilation. An electric charge transportation layer of the present invention is made to contain various additive agents, and they can also be used for it. For example, plasticizers, such as diphenyl, m-Couphenyl, and Dibutyl phthalate, Surface lubricant, such as silicone oil, graft type silicon polymer, and various fluorocarbon, Antioxidants, such as potential stabilizer, such as a dicyanovinyl compound and a carbazole derivative, beta-carotene, nickel complex, and 1.4-diazabicyclo [2, 2, 2] octane, etc. can be mentioned. An electric charge generating substance of inorganic matter [ charge generating layer / which is used by the present invention ], such as selenium, selenium tellurium, and an amorphous silicon, Pyrylium system dye, thia Pyrylium system dye, Azulenium system dye, thia cyanine dye, Cationic dye, such as Kino cyanine dye and Azulenium system dye, Squarilium salt system dye, They are paints, anthanthrone system paints, and Jibenz pyrene quinone system paints 19 system to phthalocyanine 2, independent in material chosen from organic electric charge generating substances, such as polycyclic quinone paints, such as Bilan TRON system paints, indigo system paints, quinacridone paints, and azo pigment, -- it is -- carrying out -- it can combine and use and can use as an evaporation layer or a coating layer. Although azo pigment is various among the above-mentioned electric charge generating substances used for the present invention, a typical constructional example of high azo pigment of especially an effect is shown below. As a general formula of azo pigment, it is A about a central bone rank as follows. A child N=N Cpn If a coupler part is expressed as Cp (it is n=2 *or3 here), as an example of A, the following will be mentioned first. As the example of Cp cp-6 (R: Alkyl, Aryl, etc.) etc is mentioned. These central bone ranks A and Kapler Cp form paints which serve as quality of electric charge a living thing of one shot with combination suitably. A charge generating layer can be obtained by making a suitable binder distribute the above-mentioned electric charge generating substance, and being able to form by Coating(ing) this on a base material, and forming a vapor deposition film with a vacuum evaporation system. It can choose from insulating resin extensive as the above-mentioned binder, and can choose from organic light conductive polymers, such as poly-N-vinylcarbazole, polyvinyl anthracene, polyvinyl pyrene. Preferably, they are polyvinyl butyral and Boryey rates (polycondensation polymer of bisphenol A and phthalic acid, etc.), Polycarbonate, polyester, Phenoxy resin, polyvinyl acetate, Insulating resin, such as an acrylic resin, polyacrylamide resin, polyamide, polyvinyl pyridine, cellulose system resin, urethane resin, an epoxy resin, casein, polyvinyl alcohol, and polyvinyl pyrrolidone, can be mentioned. As for resin contained in a charge generating layer, 80 % of the weight or less, preferably 40 % of the weight or less are suitable. As an organic solvent used in the case of Coating, they are ketone [, such as alcohols, such as methanol, ethanol, and an iso proper tool acetone, methyl ethyl ketone, and cyclohexanone, ], N, and N-Dimethylform amide and N. Sulfo Xide, such as amide, such as N-Dimethyl aceto amide, and dimethyl sulfoxide Ether, such as a tetrahydro franc, dioxane, and Engineering * Chillen glycol monomethyl ether, Ester, such as acetic acid methyl and ethyl acetate, chloroform, a methylene chloride, Aromatic series, such as fatty series halogenated hydrocarbon, such as dichloro ethylene, a carbon tetrachloride, and trichloroethylene, or benzene, toluene, xylene, mono-chlorobenzene, and dichlorobenzene, can be used. In order to pour in a career to an electric charge transportation layer into a life of an electric charge career which contained the as many of organic photo conductors as possible, and occurred in order that a charge generating layer might obtain sufficient Absorbance, It is preferred to consider it as a thin film layer with film thickness of a less than thin film layer, for example, 5 micrometers, preferably 0.01 micrometer - one micrometer. A photosensitive layer which consists of lamination structure of such a charge generating layer and an electric charge transportation layer is provided on a conductive base material. That in which the base material itself has conductivity as a conductive base material, for example, aluminum, An aluminium alloy, copper, zinc, stainless steel, etc. can be used, In addition, aluminum, an aluminium alloy, indium oxide, tin oxide, A plastic which has the layer in which tunic formation was carried out by vacuum evaporation method in an indium oxide tin oxide alloy etc., Conductive particles (for example, aluminum dust, titanium oxide, tin oxide, a zinc oxide) A plastic etc. which have a base material which covered carbon black, a silver granule child, etc. on a plastic or the metal base material with a suitable binder, a base material with which a plastic and paper were impregnated in conductive particles, and a conductive polymer can be used. Bottom Stratification which has a barrier function and an adhesion function in the middle of a conductive base material and a photosensitive layer can also be provided. Bottom Stratification are casein, polyvinyl alcohol, and 2l. and a Roselle sirloin, It can form with ethylene acrylic acid copolymer polyamide (nylon 6, Nylon 66, Nylon 610, copolymerization nylon, alkoxy methylation nylon, etc.), polyurethane, gelatin, an aluminum oxide, etc. 1, preferably 0.5 micrometer ~ 3 micrometers of 0.1 micrometer ~ 5 micrometers are suitable for film thickness of bottom Stratification. A disazo pigment or U.S. Pat. No. 3554745 above-mentioned in another example of the present invention, Kinky thread Rium dye of an indication in 3567438, a 3586500 gazette, etc., paints which have optical conductivity, such as thia Pyrylium dye, Selena pyrylium dye, benzokinky thread Rium dye, benzothia Pyrylium dye, naphth kinky thread Rium dye, and naphth thia Pyrylium dye, and the increase of dye -- admiration -- an agent -- As -- it can use. the increase of a eutectic crystal complex with an electric insulation polymer which has kinky thread Rium dye and an alkylidene Diarylene portion of an indication in a U.S. Pat. No. 3684502 gazette etc. in another example -- admiration -- an agent -- As -- it can also use. This eutectic crystal complex is a halogenated hydrocarbon solvent (for example, dichloromethane), for example about 4-[4-Screw- (2~chloro ethyl) aminophenyl]-2 and 6-CIF enyl Thiabyrillium perchlorate and poly (4 and 4'-Isoblobilidene diphenylene Caponate). Chloroform, a carbon tetrachloride, 1.l-dichloroethane, 1.2-dichloroethane, It is a nonpolar solvent (for example, obtained as a particle-like eutectic crystal complex by adding hexane, octane, Deccan, 2, 2.4-Trimethyl benzene, and ligroin.) to this after dissolving in 1,1.2-dichloroethane, chlorobenzene, Bromo benzene, and 1,2-dichlorobenzene. In an electrophotographic photoreceptor in this example, it is a styrene butadiene copolymer. Silicon resin, Vinyl resin, a chlorination Vinylidene-Acrylonitrile copolymer styrene acrylonitrile copolymer, A vinyl acetate VCM/PVC copolymer, polyvinyl butyral, polymethyl methacrylate, Polly N butyl methacrylate, polyester, and cellulose ester can be contained as a binder. It not only uses an electrophotographic photoreceptor of the present invention for an electrophotographic copying machine, but it can use it for electrophotographic applicable fields, such as a laser beam printer, a CRT printer, and an electrophotographic type platemaking system, widely. According to the present invention, change of bright section potential when an electrophotographic photoreceptor of high sensitivity can be given and repetition electrification and exposure are performed, and dark part potential has a small advantage. Hereinafter, Follow ° Explanation carries out the present invention at an example. Example 1 The following structural formula Listen part handbill Coating liquid was prepared by Sand mill at 24:00 with liquid which came out and dissolved 2 g of butyral resin (degree % of 63 mol of butyral-izing) for disazo pigment 5g shown in 100 m of cyclohexanone 1!. This Coating liquid was applied by Mai Ya Bar so that dry film thickness might be set to 0.2 micrometer on an aluminum sheet, and a charge generating layer was created. Next, illustration compound Nalpha(6) lO-g and 10 g of polycarbonate resin (weight average molecular weight 20000) are dissolved in 70 g of mono-chlorobenzene as an electric charge transportation substance, This liquid was applied by Mai Ya Bar on a previous charge generating layer, and Establishment created an electrophotographic photoreceptor for an electric charge transportation layer whose dry film thickness is 20 micrometers. thus -- using electrostatic copying paper test equipment (M o d e l-S P-428: product made from the Kawaguchi electrical machinery) for a created electrophotographic photoreceptor -- a Static method -- 1 -- after carrying out corona electrical charging at 5 kV and holding for 1 second in a dark place, it exposed by illumination 201ux and investigated the electrification characteristic. A light exposure (E'A) required to decrease potential (vl) when carrying out dark attenuation for 1 second with surface potential (V O) to 4 as the electrification characteristic was measured. In order to measure change of bright section potential when it is used repeatedly, and dark part potential, A photo conductor created in this example was stuck on a cylinder for photoconductive drums of a PPC copying machine (NP-3525: made by Canon), a 5000-sheet copy was performed by the opportunity, and change of bright section potential (V L) after the first stage and a 5000-sheet copy and dark part potential (VD) was measured. the first stage -- (7) -- V and vL -- each #-700V It set up so that it might be set to -200V. The result is shown below. 1st Table Example 2~10. comparison 1 example 1~3 instead of [ of illustration compound h (6) used in the Example 1 as an electric charge transportation substance in each of this example ] -- an illustration compound side (1), (2), (5), (7), (9), (I I), and (13). A disazo pigment of the following structural formula was used as an electric charge generating substance, using (17) and (18), and also an electrophotographic photoreceptor was created by the same method as Example 1. The electrophotographic properties of each photo conductor were measured by the same method as Example I. For comparison, a compound of the following structure was used as an electric charge transportation substance, by same method, an electrophotographic photoreceptor was created and electrophotographic properties were measured. Each result is shown below. (JP,57-195254,A statement) 2 * (JP,56-119132,A statement) More clearly than the 3 * (JP,51-93224,A statement) 1st table~3rd table, a photo conductor using p-terphenyl compound of the present invention has good sensitivity compared with a comparative example, and it understands it that there is also little potential change at the time of durability. Example 11 They are 5 g of methoxymethyl-ized nylon resin (number average molecule fi32000), and alcoholic soluble copolymerization nylon resin (number average molecular weight 29000) log on an aluminum board. Liquid which dissolved in methanol 95g was applied by Mai Ya Bar, and film thickness after dryness provided a lower influence layer which is 1 micrometer. Next, the following structural formula It came out and a ball mill distribution machine performed distribution for 5 g of electric charge generating substance 10g1 butyral resin (degree % of 63 mol of butyral-izing) and dioxane 200g which are shown for 48 hours. These dispersion liquid were applied with a braid coating method on bottom Stratification manufactured previously, and film thickness after dryness formed a charge generating layer which is 0.15 micrometer. Next, the illustration compound No and (14) 10 g and polymethyl methacrylate resin (weight average molecular weight 50000) log are dissolved in 70 g of mono-chlorobenzene, It applied with a braid coating method on a charge generating layer formed previously, and film thickness after dryness formed an electric charge transportation layer which is 19 micrometers. in this way, a created photo conductor -- 1 -- 5-kV corona discharge was performed. Surface potential at this time was measured (initial potential V.). Surface potential after neglecting this photo conductor for 1 second in a dark place was measured. Sensitivity was evaluated by measuring a light exposure (E Vx+muJ /c rd) required to decrease potential vl after carrying out dark attenuation to %. Under the present circumstances, a ternary system semiconductor laser (appearance crab 5mW; oscillation wavelength of 780 nm) of gallium / aluminum / top matter was used as a light source. These results were as follows. Vo : -698V V+ : 694V E '/2 : The above-mentioned photo conductor was set to a laser beam printer (LBP-CX: made by Canon) which is an electrophotographic method printer of a reversal development method which equipped 0.60 muJ /cm'2 order with a semiconductor laser same as the above, and an actual image formation test was used. The conditions are as follows. - Surface potential after surface potential;700after next electrification v, and image exposure, and -150V (light exposure 2.0pJ/crr?>) Transfer potential; +700V, development agent polarity; cathode nature, process speed; 50 mm/sec Development conditions (development bias); -450V, an image exposure scanning method; although an image scan, red complete exposure of front [ the - following electrification ] exposure;501ux-5ec, and image formation carried out line-scan [ of the laser beam ] according to a character signal and an image signal and were performed, a print with a character and a good picture was obtained. When image output of 3000 continuation was performed, a good print stable from the first stage to 3000 sheets was obtained. Example 12 In addition to liquid which melted Phenoxy resin 5g, 10 g of titanyloxyphthalocyanine was distributed by a ball mill to dioxane 485g for 2 hours. Applied these dispersion liquid by Mai Ya Bar on an aluminum sheet, it was made to dry by 80 degreeC for 2 hours, and a 0.5-micrometer charge generating layer was formed. Next, liquid which dissolved the illustration compound No, (19) Log, and 10 g of screw phenol Z type polycarbonate resin (heavy 1 average molecule fi50000) in 70 g of mono-chlorobenzene, Applied by Mai Ya Bar on a charge generating layer formed previously, it was made to dry by 110 degreeC for 1 hour, and a 19-micrometer electric charge transportation layer was formed. Thus, a created photo conductor was measured by the same method as Example 11. This result is shown below. Vo: -701V V : -694V 8% : 0.65microJ /c A Example 13 4-(4-dimethylaminophenyl)-2, 6-CIF enyl Thia pyrylium barcro rate of 3 g and the illustration compound No, (21) was mixed in 5 g and toluene (50 weight sections)-dioxane (50 weight sections) solution 100g of polyester resin (weight average molecular weight 49000), and it distributed by a ball mill for 6 hours. Applied these dispersion liquid by Mai Ya Bar on an aluminum sheet, it was made to dry by 100 degreeC for 2 hours, and a 15-micrometer photosensitive layer was formed. A photo conductor created in this way was measured by the same method as Example 1. This result is shown below. Vo : -700V V: -695V E % : 2.9 iux35ec (First stage) Vo : -700V V, t : -200V (After 5000-sheet durability) Vo : -690V V+ : -224V Example 14 It is ammonia solution solution (cold 1 Si 11.2 was applied by Mai Ya Bar, and dry film thickness formed bottom Stratification which is 1 micrometer.) of casein on an aluminum board. An electric charge transportation layer and a charge generating layer of Example 3 were laminated successively on it, except differing in layer composition, a photo conductor was formed completely like Example 1, and the electrification characteristic was measured like Example 1. However, electrification polarity was set to phi. This result is shown below. vo : phi689v ■ 20 -- 680v E[: 2.8j!ux@sec Example 15 The 5% methanol solution of soluble nylon (6-66-610- 12 4 yuan nylon copolymer) was applied on an aluminum board, and dry film thickness formed bottom Stratification which is 0.5 micrometer. Next, the following structural formula Liquid which came out and melted account illustration compound No.of tetra-Hydrofur(10) 5g and 10 g of screw phenol Z type vehicle liquor Bonate resin (weight average molecular weight 50000) for disazo pigment 5g shown in mono-chlorobenzene 30mj! is added to dispersion liquid created previously, It distributed by Sand mill for further 2 hours. It applied and dried by Mai Ya Bar so that film thickness after drying these dispersion liquid on bottom Stratification created previously might be set to 20 micrometers. The electrophotographic properties of a photo conductor created in this way were measured by the same method as Example 1. This result is shown below. Vo : -699V V,: -692V E -- each : 3.2 j!uxIlsec -- [Effect of the Invention] -- it explained above -- as the electrophotographic photoreceptor which has a photosensitive layer containing p-terphenyl compound which becomes the present invention being high sensitivity, and facing the continuation image formation by repetition electrification and exposure -- change of bright section potential and dark part potential -- smallness (it excels in endurance.)

[Brief Description of the Drawings]

Drawing 1 is example Noof compound. It is an infrared-absorption-spectrum figure (KBr tablet method) of (2).