JP3491718B2 - Electrophotographic photoreceptor - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electrophotographic photosensitive member suitable for digital light input used in electrophotography. More specifically, the present invention relates to an electrophotographic photosensitive member (high γ value photosensitive member) that has a threshold value in a light attenuation curve and has a small change in exposure energy that causes a transition from a high surface potential to a low surface potential.

[0002]

2. Description of the Related Art Electrophotographic methods such as the Carlson method have been developed with a focus on rendering an original image in an analog manner. Therefore, in order to faithfully reproduce the brightness of the input light as the brightness of the toner image, the photoconductor used therein may have a characteristic that a photocurrent flows linearly similar to (the logarithmic value of) the input light amount. I have been asked. Therefore, it has been a principle to select a photosensitizer having such characteristics (low γ characteristics) as a material for the photoconductor. Therefore, it starts from a material close to a simple photoconductor in the early stage of electrophotography, and is similar to a photosensitive layer in an amorphous state of selenium (Se), an amorphous layer of silicon (Si), and an amorphous layer of Se. The prepared ZnO tie layer or the like has been used as a photoreceptor. Furthermore, in recent years, a so-called function-separated type photosensitive layer using an organic semiconductor has been developed until it is used as a photoconductor. However, recently, the combination of electrophotographic technology and computer / communication has led to a rapid shift in the printer and facsimile systems to the electrophotographic recording system.In addition, even with ordinary copy machines, reversal, clipping, whiteout, etc. It is becoming a method that enables image processing. Therefore, it is desired to change the recording method of electrophotography from the conventional analog recording format for PPC to the digital recording format.

Further, as an input light source used in the digital recording system, there are a gas laser such as an Ar laser and a He-Ne laser, a semiconductor laser, a shutter array such as a liquid crystal, an LED and an EL array. Among them, semiconductor lasers are currently the mainstream because they can be downsized and reduced in cost, and a photosensitizer having high sensitivity in the near infrared region, which is the oscillation wavelength of semiconductor lasers, is required.

Further, as described above, the photoconductor used in the traditional electrophotographic method based on the analog concept is
It has a low γ characteristic, and due to its characteristics, it is suitable for electronic photography, such as a printer for outputting data from a computer, or a digital copy for digitally processing an image, in which an input digital optical signal must be rendered as a digital image. Not suitable. That is, even the deterioration of the digital signal in the signal path from the computer or image processing device to the electrophotographic device, or the aberration caused by the optical system for converging the writing light beam or forming the original image. However, the photoconductors using these photosensitizers faithfully depict the original digital images.
Therefore, it is strongly desired to provide a digital photoconductor having high sensitivity and high γ characteristics which can be used in this field. Under such circumstances, Japanese Patent Application Laid-Open No. 1-169454 discloses the concept of a digital photoconductor.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the present situation, and has excellent performance (high γ characteristic) with respect to digital optical input, and also has excellent repeatability, long life and high stability. The purpose of the present invention is to provide a new photosensitive member.

[0006]

In the present invention, as a result of intensive studies for solving the above-mentioned problems, as a result, an electronic device in which a photosensitive layer formed by dispersing phthalocyanine in a binder resin is provided on a conductive support. In a photographic photoreceptor, a photoreceptor containing an aromatic amine-based charge-transporting substance in a range of 0.01 to 10% by weight in a photosensitive layer has excellent performance (high γ characteristic) for digital light input. The present invention has been completed by discovering that it is a digital photoconductor having a long life and a high stability as well as having excellent repeating characteristics.

That is, the gist of the present invention is phthalocyanine.
On the conductive support
In the electrophotographic photosensitive member provided, an aromatic amine is contained in the photosensitive layer.
0.01-based charge transport material5Wt% content, electronic
In the photo decay curveThe initial potential immediately after charging
V ₀ (V), residual potential of 50 μJ / cm ² Illuminate the light of
V is the surface potential when radiated _r Difference between the two when (V)
ΔV (V ₀ -V _r ), "95% surface potential" V
₉₅ Is the surface potential obtained by adding 95% of ΔV to the residual potential.
(V ₉₅ = ΔV × 0.95 + V _r ) And take "5% surface charge
"V" _Five As a surface with 5% of ΔV added to the residual potential
Potential (V _Five = ΔV × 0.05 + V _r ), V ₉₅ , V
_Five The exposure energy that gives
Gee "E ₉₅ , "5% exposure energy" E _Five As
E _Five / E ₉₅ Is less than or equal to 5Characterized byDigital
Single layer type for optical inputIt exists in electrophotographic photoreceptors.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be described in detail below. <1> Phthalocyanine The phthalocyanine used in the present invention can be selected from those usually used for electrophotographic photoreceptors, and its central atom or atomic group is, for example, hydrogen, magnesium, calcium, zinc, aluminum, titanium, tin. , Lead, vanadium, iron, cobalt, nickel, copper, silicon, gallium and the like, or oxides or halides of these atoms. Among these, preferably hydrogen, magnesium, titanyl, vanadyl, copper, cobalt, nickel, more preferably hydrogen, titanyl, vanadyl,
It is copper. Even if these phthalocyanines are used alone,
You may use it in a mixture.

Of these phthalocyanines, titanyl phthalocyanine is particularly preferable. Although various crystal forms of titanyl phthalocyanine have been known so far, as the titanyl phthalocyanine used in the present invention, amorphous form, α form, β form, C form, and CuK α line in the X-ray diffraction spectrum have a Bragg angle (2θ). ± 0.2 °)
The crystal form which shows peaks at 9.5 °, 24.1 ° and 27.3 °, and usually has the strongest intensity of the diffraction peak at 27.3 ° can be mentioned. Among them, amorphous type, β type and Bragg angle (2θ ± 0.2 °) 9.5 °, 24.1 ° and 27.
A crystal form having a peak at 3 ° is preferable, and further, a Bragg angle (2θ ± 0.2 °) of 9.5 in an X-ray diffraction spectrum.
Most preferred is the crystalline form of titanyl phthalocyanine which exhibits peaks at °, 24.1 ° and 27.3 °.

The method for synthesizing phthalocyanine is described in Moser and Thomas's "Phthalocyanine Compound" (MOSER).
and THOMAS, “Phthalocyanin”
eCompounds "), for example, in the case of titanyl phthalocyanine, the o-phthalonitrile and titanium tetrachloride may be melted by heating or in the presence of an organic solvent such as α-chloronaphthalene. A good yield can be obtained by heating or heating 1,3-diiminoisoindoline and tetrabutoxytitanium with an organic solvent such as N-methylpyrrolidone.
The titanyl phthalocyanine thus synthesized may contain a chlorine-substituted phthalocyanine. Further, as a method for producing titanyl phthalocyanine having diffraction peaks at 9.5 °, 24.1 ° and 27.3 ° described above, for example, titanyl phthalocyanine is mechanically ground and water and an organic solvent are added. Japanese Patent Application Laid-Open No. 2-289
Although it can be produced by the method described in Japanese Patent No. 658, etc., it is not limited to this method, and for example, even if it is produced by another manufacturing method, as long as it belongs to the same crystal form crystallographically. It can be used.

<2> Aromatic amine charge transport material The charge transport material used in the present invention is added for the purpose of controlling the trap state in the photosensitive layer. Although not focusing on its hole transporting ability, it has a nitrogen atom and an aromatic ring in the molecule. For example, oxadiazole derivatives such as 2,5-bis (p-diethylaminophenyl) oxadiazole, pyrazoline derivatives such as 1-phenyl-3- (p-diethylaminostyryl) -5- (p-diethylaminophenyl) pyrazoline, p-Diethylaminobenzaldehyde-N, N-diphenylhydrazone and p-diethylaminobenzaldehyde-N-α-naphthyl-N
-Hydrazone derivatives such as phenylhydrazone, 1,1-
Bis (4-N, N-diethylamino-2-methylphenyl) heptane, 1,1,2,2-tetrakis (4-N,
Polyarylalkane derivatives such as N-diethylamino-2-methylphenyl) ethane, oxazole derivatives such as 2- (p-diethylaminostyryl) -6-diethylaminobenzoxazole, 2- (p-diethylaminostyryl) -6-diethylaminobenzothiazole And triarylamine derivatives such as triphenylamine, carbazole derivatives such as N-ethylcarbazole and N-isopropylcarbazole, and amino-substituted chalcone derivatives.

Among them, 2,5-bis (p-diethylaminophenyl) oxadiazole, 2,5-bis (p-dimethylaminophenyl) oxadiazole, 2,5-bis (p-dibutylaminophenyl) oxadiazole Azole,
Oxadiazole derivatives such as The amount added to the photosensitive layer is 0.01 to 5 % by weight, preferably 0.01 to 3 % by weight, based on the solid content of the photosensitive layer.
If the amount added is too large, the residual potential rises, the threshold value is erased, and the like, which is not preferable for a digital electrophotographic photoreceptor.

<3> Electrophotographic Photoreceptor In the electrophotographic photoreceptor of the present invention, a photosensitive layer in which the above-mentioned phthalocyanine and the above-mentioned aromatic amine charge-transporting substance are dispersed together with a binder resin is provided on a conductive support. It is obtained by providing. As the binder resin, polycarbonate, polyester, methacrylic resin, acrylic resin, polyvinyl chloride, polyvinylidene chloride, polystyrene, polyvinyl acetate, styrene-butadiene copolymer, vinylidene chloride-acrylonitrile copolymer, vinyl chloride-vinyl acetate Copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, silicone resin, silicone-alkyd resin, phenol-formaldehyde resin, styrene-
Insulating resins such as alkyd resins, poly-N-vinylcarbazole, polyvinyl butyral, fluororesins, urethane resins, alkyd resins, epoxy resins and melamine resins, or semi-conductive resins such as polyvinylcarbazole and polysilane can be used. Further, a thermosetting resin and a photocurable resin which are crosslinked by heat and / or light can also be used.

When using these binders,
Additives such as a plasticizer, a fluidity imparting agent, and a pinhole inhibitor can be added as necessary. As the conductive support used in the present invention, a metal plate, a metal drum, or a conductive polymer, a conductive compound such as indium oxide, or a conductive thin layer made of a metal such as aluminum, palladium or gold is applied and vapor deposited. By means such as laminating,
Those provided in a gas such as paper, ceramics, plastics, and films are used. These forms are sheet-like,
It may take any form such as a drum shape, a belt shape, or a seamless belt shape.

The solvent used for the coating liquid is preferably selected from those which dissolve the binder resin and the charge transporting substance and do not grow the phthalocyanine crystals which hinder the performance. , For example, toluene, xylene, hydrocarbons such as mineral spirits, acetone, methyl ethyl ketone, methyl butyl ketone, ketones such as cyclohexanone, dichloromethane, dichloroethane, trichloroethane, halogenated hydrocarbons such as chlorobenzene, tetrahydrofuran, dioxane,
Ethers such as monoglyme, diglyme and anisole, alcohols such as methanol, ethanol, propanol, butanol, methyl cellosolve, ethyl cellosolve, butyl cellosolve, cyclohexanol, ethyl acetate, propyl acetate, esters such as butyl acetate, Examples thereof include amides such as dimethylformamide and N-methylpyrrolidone. For these solvents, 1
The seeds may be used alone or in combination of two or more.

The electrophotographic photosensitive member of the present invention comprises a ball mill, an attritor, an ultrasonic disperser, a homomixer, a paint mixer, a sand mill, a phthalocyanine, a binder resin, a charge-transporting substance, and additives which are optionally added.
Distribute evenly with a kneading disperser such as an attritor, disperser, ultrasonic disperser, etc., and use an air doctor coater,
A single layer is prepared by coating the photoconductor composition on the conductive gas by a coating method such as a plate coater, a rod coater, a reverse roll coater, a spray coater, a hot coater, a dip coater, a ring coater, a squeeze coater, and a gravure coater. To form a photosensitive layer.

After coating, drying is carried out until a sufficient charging potential is imparted as a photoconductive layer. Usually, the drying is performed at a temperature of 30 to 300 ° C. for 1 minute to 24 hours after preliminary drying at room temperature. In the photosensitive layer of the present invention, the compounding ratio of the phthalocyanine and the binder resin is such that when the amount of the former is increased, the threshold value of the photosensitive property is lowered and the sensitivity is improved,
The chargeability decreases. On the contrary, when the amount of the former is decreased, the threshold value of the photosensitivity is increased and the sensitivity is lowered, resulting in poor practicability.
Therefore, the compounding ratio is usually 10 to 120 parts by weight, preferably 20 to 100 parts by weight with respect to 100 parts by weight of the binder resin.

In the photosensitive layer of the present invention, the aromatic amine charge transfer agent is contained in the photosensitive layer in an amount of 0.01 to 10% by weight, preferably 0.01 to 5% by weight, more preferably 0.0.
It is added in a proportion of 1 to 3% by weight. The addition of this agent improves the surface potential stability of repetitive characteristics. If the concentration is too low, the stability will not be sufficiently improved, and if it is too high, the residual potential will increase and the digital property will decrease. The electrophotographic photosensitive member manufactured according to the above means of the present invention usually has a resin / photoconductive material ratio of 1 or more by weight. Therefore, for example, as compared with the case of the conventional photoconductor using zinc oxide in which the weight ratio of resin / photoconductive material is 0.2, the amount of resin is large and therefore the physical strength of the coating film is large.
It is possible to realize a flexible photoconductor.

Further, an undercoat layer and an overcoat layer may be provided for the purpose of improving various characteristics of the photoreceptor. Further, additives such as antioxidants may be added for the purpose of improving stability and the like. The thickness of the obtained photosensitive layer is preferably in the range of 5 to 50 μm, more preferably 10 to 30 μm.

The photoconductor of the present invention manufactured as described above has a threshold value in the light decay curve, has a large adhesiveness with the conductive support, has a good moisture resistance, and has a small change with time. It has practically excellent characteristics such as little toxicity problem, easy production, and low cost. In the present invention, “having a threshold value in the light attenuation curve” means the following. That is, in the light decay curve, the initial potential immediately after charging is V
_o (V), and the difference between the two when the surface potential upon irradiation with light having a residual potential of 50 μJ / cm ² is V _r (V) is ΔV (V _o −V _r ). At this time, the surface potential (V ₉₅ = ΔV × 0.95 + V _r ) obtained by adding 95% of ΔV to the residual potential is taken as “95% surface potential” V ₉₅ , and “5%
As the “surface potential” V ₅ , the surface potential (V ₅ = ΔV × 0.05 + V _r ) obtained by adding 5% of ΔV to the residual potential is taken as V 5.
_The exposure energy giving ₉₅ and V ₅ is “95% exposure energy” E ₉₅ . Determined as "5% exposure energy" E _5, it is intended to mean that the value of E ₅ / E ₉₅ is 5 or less.

The photoreceptor of the present invention obtained as described above is
Compared with the case of the conventional photoconductor, it can be used as a photoconductor for digital light input because of a specific flow of photocurrent. That is, in the conventional photoconductor, as described above, the photocurrent of a quantity linearly corresponding to (the logarithmic value of) the input light quantity flows, whereas in the photoconductor of the present invention, up to a certain input light quantity. The photocurrent does not flow, or is very small, and the photocurrent suddenly starts to flow immediately after the light amount is exceeded.

In digital recording, the image gradation is expressed by the dot area, so that the photosensitivity characteristics of the photoconductor used in this recording method are preferably those described above. This is because, even if the laser spot is accurately modulated by the optical system, the distribution of the light quantity of the spot itself and the halo cannot be avoided in principle. Therefore, in the conventional photoconductor, which changes the light energy (input light amount) stepwise, the dot pattern changes due to the light amount change, which causes fog as noise. Therefore, the photoconductor of the present invention is a photoconductor advantageous for a digital light input photoconductor.

[0023]

EXAMPLES The present invention will be described in more detail below with reference to examples. <Production Example of titanyl phthalocyanine> 58 g of 1,3-diiminoisoindoline and 51 g of tetrabutoxytitanium are reacted in 300 ml of α-chloronaphthalene at 210 ° C. for 5 hours, and then heat filtered at 150 ° C. to obtain α-chloronaphthalene, It was washed with dimethylformamide (DMF) in this order.
Then, it was washed with hot DMF, hot water and methanol and dried to obtain 51 g of titanyl phthalocyanine.

6 g of the above-mentioned titanyl phthalocyanine and 50 g of glass beads were placed in a 100 ml polybin and ground with a paint shaker (Red Devil) for 40 hours.
Then, the titanyl phthalocyanine was separated from the glass beads with methanol, and the obtained titanyl phthalocyanine was washed with 100 ml of water. This titanyl phthalocyanine wet cake was mixed with 100 ml of water and 10 parts of dichlorobenzene.
The mixture was added to the mixed solution of ml, stirred for 1 hour, filtered and washed with methanol to obtain 4.3 g of titanyl phthalocyanine.
The X-ray diagram of this titanyl phthalocyanine is, as shown in FIG. 1, a Bragg angle (2θ ± 0.2 °) of 9.5 °, 24.1.
The peaks are at 2 ° and 27.3 °, and the intensity of the diffraction peak at 27.3 ° is the strongest. Next, examples of the electrophotographic photosensitive member of the present invention using a commercially available phthalocyanine and the titanyl phthalocyanine obtained in Production Example as a photosensitizer will be described.

Example 1 1.0 g of the titanyl phthalocyanine obtained in the production example was used to obtain 8.0 g of a fluororesin (Sephral coat A202B, solid content 50% by weight, Central Glass Co., Ltd.), 2,5-bis (p-diethylamino). Phenyl) -1,3,4-oxadiazole 7.5 mg (0.1% based on the total solid content of the photosensitive layer).
15% by weight), toluene 20 g, glass beads (diameter 2
(35 mm) and sealed in a glass container with a paint shaker (manufactured by Red Devil Co.) for 4 hours. After dispersion, the glass beads were separated to obtain a photoreceptor coating solution.
This photoreceptor coating liquid was applied on a degreased aluminum sheet having a thickness of 90 μm by the wire bar method, preliminarily dried at room temperature, and then dried in an oven at 100 ° C. for 1 hour. As a result, a photoreceptor having a film thickness of 15.2 μm was obtained.

Example 2 The same operation as in Example 1 except that 2,5-bis (p-diethylaminophenyl) -1,3,4-oxadiazole in Example 1 was replaced with p-diethylaminobenzaldehyde diphenylhydrazone. Then, a photoreceptor having a film thickness of 15.9 μm was obtained.

Example 3 The same operation as in Example 1 was carried out except that the titanyl phthalocyanine in Example 1 was changed to X-type metal-free phthalocyanine to obtain a photoreceptor having a film thickness of 15.8 μm.

Example 4 The fluororesin of Example 1 was replaced with a polycarbonate resin (APE
C-HT, manufactured by Bayer Japan) except that Example 1 was used.
The same operation as above was carried out to obtain a photoreceptor having a film thickness of 16.2 μm.

Example 5 A membrane was prepared in the same manner as in Example 4 except that p-diethylaminobenzaldehyde diphenylhydrazone was used in place of 2,5-bis (p-diethylaminophenyl) -1,3,4-oxadiazole. A photoreceptor having a thickness of 16.0 μm was obtained.

Example 6 The fluororesin of Example 1 was changed from 8.0 g to 6.7 g, 0.7 g of isocyanate (Coronate HX, manufactured by Nippon Polyurethane Industry Co., Ltd.) was added, and further dibutyltin dilaurate as a catalyst was added to 0.7 g. The same operation as in Example 1 was carried out except that 1 mg was added to obtain a photoreceptor having a film thickness of 15.8 μm.
Hereinafter, comparative examples used to evaluate each example of the present invention will be described.

Comparative Example 1 The procedure of Example 1 was repeated except that the 2,5-bis (p-diethylaminophenyl) -1,3,4-oxadiazole of Example 1 was omitted, and the film thickness was 15. A 2 μm photosensitive member was obtained.

Comparative Example 2 The procedure of Example 3 was repeated except that the 2,5-bis (p-diethylaminophenyl) -1,3,4-oxadiazole of Example 3 was omitted, and the film thickness was 15. A photoconductor of 5 μm was obtained.

Comparative Example 3 The same operation as in Example 4 was carried out except that 2,5-bis (p-diethylaminophenyl) -1,3,4-oxadiazole in Example 4 was omitted, and a film thickness of 15. A 9 μm photosensitive member was obtained.

Comparative Example 4 The same operation as in Example 6 was carried out except that 2,5-bis (p-diethylaminophenyl) -1,3,4-oxadiazole in Example 6 was omitted, and a film thickness of 15. A 1 μm photosensitive member was obtained.

Comparative Example 5 7.5 mg of 2,5-bis (p-diethylaminophenyl) -1,3,4-oxadiazole of Example 1 (0.15% by weight based on the total solid content of the photosensitive layer) was added to 0. Change to 0.75 g (15% by weight), and perform the same operation as in Example 1,
A photoconductor having a film thickness of 15.6 μm was obtained.

<Evaluation of Electrophotographic Photoreceptor> The photosensitivity and repetitive characteristics of the photoreceptors obtained in the respective examples and comparative examples obtained above were measured by a photoreceptor evaluation device (Cynthia-55, manufactured by Gentec). It evaluated using.

(1) Characteristics of Photoreceptor First, the corona charged at a voltage of +6.0 KV, and monochromatic light of 780 nm having different light intensity is applied to each of the corona-charged photoconductors. (Characteristic curve of surface potential against irradiation time) was measured. Then, the surface potential after irradiation for a certain period of time (here, 0.075 seconds) obtained from the curve was plotted against the light energy. This was made into the light attenuation curve.

As shown in FIG. 2, the optical attenuation curve
The initial potential immediately after charging is V_o(V), as residual potential
50 μJ / cm²The surface potential when irradiated is V_r(V)
The difference between the two is ΔV (= V_o-V_r). This
When, "95% surface potential" V ₉₅As the residual potential ΔV
Surface potential (V₉₅= ΔV × 0.95 +
V_r), "5% surface potential" V_FiveAs the residual potential
Surface potential (V_Five= ΔV × 0.0
5 + V_r), V₉₅, V_FiveExposure energy that gives
"95% exposure energy" E₉₅, "5% exposure
Energy "E _FiveAs E,_Five/ E₉₅The value of
Based on the evaluation criteria, we aimed to enable digital recording.

0 <E ₅ / E ₉₅ ≦ 5: Digitally recordable 5 <E ₅ / E ₉₅ : Analog recording Further, among 0 <E ₅ / E ₉₅ ≦ 5, the smaller E ₉₅ , the light sensitivity becomes. It can be said that it is excellent as an electrophotographic photoreceptor.

(2) The repeating characteristic evaluation process is as follows: each electrophotographic photosensitive member is positively charged (+6.0 KV), exposed (780 nm, 20 μJ /
cm ² ), negative charging (−5.3 KV), and erasing light (200 lux, tungsten lamp) were repeated, and the number N until the surface potential V _o after positive charging changed by 10% or more was recorded. Table 1 shows the evaluation results of the above characteristics.

[0041]

[Table 1]

[0042]

As described above, the photoconductor of the present invention can output a specific optical power to an optical input, that is, a digital signal regardless of whether it is analog light or digital light. Is. Therefore, it can be used for a digital recording type electrophotography, and can realize a high-quality image with a sharp edge even when used for a conventional PPC (analog light input) photoconductor.

[Brief description of drawings]

FIG. 1 is an X-ray diagram of titanyl phthalocyanine obtained in Production Example.

FIG. 2 is a diagram showing an example of an optical attenuation curve.

─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Eisuke Fujiwara 1000 Kamoshida-cho, Aoba-ku, Yokohama-shi, Kanagawa Mitsubishi Chemical Corporation Yokohama Research Institute (56) Reference JP 54-2739 (JP, A) JP JP-A-6-258852 (JP, A) JP-A-6-130704 (JP, A) JP-A-6-118676 (JP, A) JP-A-5-313387 (JP, A) JP-A-5-289379 (JP , A) JP 5-150498 (JP, A) JP 4-296369 (JP, A) JP 4-263265 (JP, A) JP 3-217462 (JP, A) JP 2-170166 (JP, A) JP-A-1-169454 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) G03G 5/00

Claims (3)

(57) [Claims] 1. An electrophotographic photosensitive member comprising a conductive support and a photosensitive layer comprising phthalocyanine dispersed in a binder resin, wherein an aromatic amine-based charge-transporting substance is added in an amount of 0.01 to 0.01 in the photosensitive layer. 5 % by weight, the electrophotographic photoreceptor had an initial potential immediately after charging in the light decay curve of V ₀ (V), and a residual potential.
As 50 μJ / cm ² Surface potential when irradiated with the light of
To V _r The difference between the two is ΔV (V ₀ -V _r )
When a, as "95% surface potential" V _95, the residual potential
Surface potential plus 95% of ΔV (V ₉₅ = ΔV × 0.9
5 + V _r ), "5% surface potential" V ₅ As a residual
Surface potential obtained by adding 5% of ΔV to the potential (V ₅ = ΔV ×
0.05 + V _r ) Is taken to give V ₉₅ and V _5.
Rugey is "95% exposure energy" E ₉₅ , "5%
Exposure energy "E ₅ It found as, E ₅ The value of / E ₉₅ is 5
A single-layer type electrophotographic photoreceptor for digital light input , characterized in that : 2. The electrophotographic photoreceptor according to claim 1, wherein the aromatic amine compound is an oxadiazole charge transport material. 3. The X-ray diffraction spectrum of phthalocyanine has a Bragg angle (2θ ± 0.2 °) of 9.5 ° and 2
3. The electrophotographic photosensitive member according to claim 1, which is a crystalline form of titanyl phthalocyanine showing peaks at 4.1 ° and 27.3 °.