JPS6088949A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain an electrophotographic sensitive body high in sensitivity by forming a photosensitive layer contg. a specified azine compd. on a conductive substrate. CONSTITUTION:A photosensitive layer formed on a conductive substrate contains a compd. represented by formula I in which each of R1-R4 is optionally substd. alkyl, aralkyl, or aryl; R5 is H or optionally substd. alkyl, aralkyl, or aryl; R6 is an N-disubstd. amino group represented by formula II or III, or alkoxy, aralkyloxy, aryl, or halogen; and R7, R8 are each H, alkyl, alkoxy, or halogen, or an atom forming a hetero ring together with R6. The compd. of formula I has a function of both of an org. photoconductive compd. and an electrostatic charge transfer compd., and it can form an electrophotographic sensitive body high in sensitivity.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an electrophotographic photoreceptor, and more particularly to an electrophotographic photoreceptor containing a novel organic photoconductive substance comprising an azine compound.

As already revealed by Carlson in U.S. Pat. A photoconductive material consisting of a support coated with a substance is used. The photoconductive material is generally first provided with a uniform surface charge in the dark after dark adaptation for a suitable period of time. This material is then tinted with a pattern of irradiation that has the effect of reducing the surface charge depending on the relative energy contained in the extreme parts of the irradiation pattern. The surface charge or electrostatic latent image thus left on the surface of the photoconductive material layer (photosensitive layer) then becomes a visible image when that surface is contacted with a suitable electrometric indicator material, ie, toner. Toner, whether contained in an insulating liquid or in a dry carrier, can be deposited on the surface of the photosensitive layer depending on the charge pattern. The deposited display material can be fixed by known means such as heat, pressure, and solvent vapor. The electrostatic latent image can also be transferred to a λth support (eg, paper, film, etc.).

It would likewise be possible to transfer the electrostatic latent image to a λth support and develop it there. Electrophotography is one of the image forming methods in which images are formed in this manner.

The basic characteristics required of a photoreceptor in such an electrophotographic method are (1) ability to be charged to an appropriate potential in a dark place, (2) less dissipation of charge in a dark place,
(3) Examples include scales that quickly dissipate charge when irradiated with light. It is true that conventionally used inorganic photoconductive materials such as selenium, cadmium sulfide, and zinc oxide have many advantages and at the same time various disadvantages. For example, selenium, which is currently widely used, satisfies the conditions (1) to (3) above, but
It also has drawbacks such as difficult manufacturing conditions, high manufacturing costs, lack of flexibility, difficult to process into a belt shape, and sensitivity to heat and mechanical shock, requiring careful handling. It is used as a photoreceptor by dispersing cadmium sulfide, abrasive oxide, and resin as a binder, but it has mechanical drawbacks such as smoothness, hardness, tensile strength, and abrasion resistance, so it cannot be used as is. Cannot be used repeatedly.

In recent years, electrophotographic photoreceptors using various organic photoconductive materials have been proposed in order to eliminate the drawbacks of these inorganic photoconductive materials, and some of them are in practical use. For example, poly-N-vinylcarbasol,! :J, 4t, 7-)IJ
A photoreceptor made of nitrofluorene-terion (U.S. Pat.
-2jrtj No. 1), and a photoreceptor whose main component is a eutectic complex consisting of a dye and a resin (4I Publication No. 7-1073j).

Although electrophotographic photoreceptors using these organic photoconductors have improved mechanical properties and flexibility to a certain extent than those using the inorganic photoconductors, they generally have low photosensitivity and cannot be used repeatedly. It was not suitable for use as an electrophotographic photoreceptor, and did not fully satisfy the requirements for an electrophotographic photoreceptor.

Furthermore, a highly sensitive electrophotographic photoreceptor has been proposed that combines a substance that generates electric charges when exposed to light (called a charge-generating substance) and a substance that can transport the generated charges (called a charge-transporting substance). has been done. For example, U.S. Patent No.
No. 7/12 discloses a photoreceptor in which a charge transport layer is provided on a charge generation layer, whereas U.S. Pat. The photoreceptor is
Additionally, US Pat. Nos. 3.76≠ and 31j each describe a photoreceptor having a photosensitive layer in which a charge generating material is dispersed in a charge transporting material.

As a charge transporting agent used in this charge generation layer, for example, JP-A-Sho! Hiro! Publication No. 3 (US Patent No.!, /10.
No. 917, the hydrazone compounds described in U.S. Patent No. 3. Pyrazoline compounds described in U.S. Patent No. 3. , tt7. ≠! Examples include triarylamine described in No. 0, but it has not been possible to obtain an electrophotographic photoreceptor having sufficient performance in terms of sensitivity.

Regarding azine compounds, Tokko Shogu 2-! 117 as a photoconductive compound and JP-A-5R-i3xa
The ≠θ publication describes it as a charge transporting compound.

Tokukai Akira again! +, l-di (N
It has been shown that symmetrical ketazine compounds synthesized from -disubstituted aminorabenzophenones have photoconductivity and charge transport properties.

However, even if the azine compounds described in these patents were used as a root conductor or as a charge transport material, an electrophotographic photoreceptor with sufficient sensitivity could not be obtained.

Furthermore, among the azine compounds described in these patents, the use of ketazine compounds in particular has the disadvantage that crystals of the getazine compound precipitate on the surface of the photoreceptor produced.

An object of the present invention is to provide a novel electrophotographic photoreceptor that eliminates the above-mentioned problems.

Another object of the present invention is to provide a new heavy equipment photoconductive material.

Another object of the present invention is to provide a compound suitable as a charge transport material for use in a photosensitive layer having a laminated structure of a charge generation layer and a charge transport layer.

As a result of intensive research, the present inventors found that among azine compounds, ≠
, di(N-disubstituted amine, benzophenone and ≠
, Ri'-di(N-disubstituted amitunobenzophenone) Asymmetric azine compounds synthesized from two different compounds, substituted chthons or substituted aldehydes, are particularly useful as photoconductive compounds and charge-transporting compounds. It was discovered that it has superior performance.

This object of the present invention is achieved by an electrophotographic photoreceptor having a layer containing an azine compound represented by the following general formula (11).

In the formula, R1, 几21 R3+ R4 may be the same or different, and each is a linear or branched alkyl group with a carbon number of ~/2, such as methyl, ethyl, propyl, butyl, benzyl, phenethyl aralkyl groups such as phenyl, aryl groups such as naphthyl, or pyrrolidino,
Represents a residue that forms a cyclic amine group with a nitrogen atom, such as piperidino or morpholino. Also, these alkyl groups,
Aralkyl groups and aryl groups may carry a substituent, and examples of the substituent include alkyl groups such as methyl and ethyl, alkoxy groups with a carbon number of up to 1 such as methoxy and ethoxy, and halogen atoms such as chlorine and bromine. It can also be derived from hydroxyl groups, cyano groups, etc.

几5 contains an N-disubstituted amino group in addition to the substituted or unsubstituted alkyl group, aralkyl group, or aryl group shown in 几1-R4.

N-disubstituted amino group, methoxy, ethoxynato carbon number/~g alkoxy, aralkyloxy group such as benzyloxy, aryloxy group such as phenoxy, and halogen atom such as chlorine, bromine, or R6
may be combined with □ or □ 8 and the benzene ring to which they are bonded to form a heterocycle such as a julolidino ring, a carbazole ring, a phenothiazine ring, or a phenoxazine ring.

R7 and R8 may be the same or different; hydrogen, an alkyl group with a carbon number of up to 1 such as methyl and ethyl, an alkoxy group with a carbon number of up to 1r such as methoxy and ethoxy, chlorine, bromine, etc. may represent a halogen atom, or may form a heterocycle together with R6.

Among the azine compounds used in the present invention, particularly preferred are those represented by the following general formula (2).

(2) R1+R2 in the formula, "3 + 1'4, R51R1
゜ is al as explained in the general formula fil, and i is also 2. 3. Shows the same thing as 几4. Specific examples of the compound represented by the general formula (1) used in the present invention are listed below.

These compounds can be synthesized by a known method using compounds represented by the following general formulas (3) and (4) and hydrazino.

几7 Next, the azine compounds used in the present invention will be explained using synthesis examples.

Synthesis of Exemplary Compound (11), v'-bis(dimethylamino)benzophenone hydrazone 7.09 and Hiro-diethylaminobenzaldehyde μ, ♂9 were heated under reflux in ethanol for 2 hours.

After cooling the reaction solution, the resulting solid was filtered and dried.

Next, recrystallize from ethanol and melting point / [7-167,
Crystal f, IP was obtained at 0C in the evening. Yield 7? Cumulative analysis value
Calculated as C28H33N5 j [C near A, /j% H near, PJ'4 N: /
! , 1! tjfi actual value C near 6.0 layer %H: 1.2
0 N: /j, 7A% Synthesis of Exemplary Compound (3), μ'-bis(dimethylamino)benzophenone hydrazone 7.09 and ≠-(N-phenyl-N-methylaminonebenzaldehyde!, 3?) in ethanol The mixture was heated under reflux for 1 hour.

After the reaction was completed, the reaction solution was cooled, and the resulting solid was filtered and dried.

Next, recrystallization was performed using a mixed solvent of benzene and n-hexane, and the melting point was 133. Evening/3ta 0c crystallization and λ2 were obtained. Yield 7r% Elemental analysis value Calculated as C3□H33N5 1 shift C near 1.27 section H: i Tata N: /≠
, 7λ actual loss + 11 shifts 027g, 1%) l near, 2
2% N: l≠j7 Other azine compounds of the present invention can be synthesized in the same manner.

When the azine compound represented by the general formula (1) is used in an electrophotographic photoreceptor, the following A is used because it functions both as a tilt-based lightning conducting compound and as a charge transporting compound.
82 types of electrophotographic photoreceptors can be used.

Type A: An electrophotographic photoreceptor having a substantially uniform and transparent photosensitive layer in combination with a sensitizer.

Type B: Electrophotographic photoreceptor combined with a charge generating compound.

Sensitizers used in the photosensitive layer of A-type electrophotographic photoreceptors include 2, 11. ．． 7-) Linitrofluorene? −
ion, chloranil, tetracyanoethylene, and U.S. Pat. ! 32.7! Electron-attracting combination force of symbol castle,
Bi-IJ IJum dyes described in U.S. Pat. No. 3,2!0°61j, U.S. Pat.

jar, 9g No. 3, US Patent No. ≠, 3μ3.9 Hiroshi,
Azacyanine dyes, triarylmethane dyes, theazino dyes described in thio described in JP-A-Kokai Sho Tough-≠t710,
There are sensitizers such as cyanine dyes.

B type electrophotographic photoreceptor has separate functions! ! JW, which is called a photoreceptor 69, is a single-layer photoreceptor consisting of one photoreceptor layer dispersed in the azine compound of the present invention, in which a charge generation compound is used as a charge transport compound, or a charge generation compound. A product consisting of a photosensitive layer of a charge generating layer containing a charge generating layer and a bottom tube transporting layer containing an azine compound of the present invention used as a charge transporting compound; Type 3 includes a photosensitive layer. Preferably, a photoreceptor of type 11i is useful in terms of electrophotographic Mf, photosensitive sensitivity, and charge retention rate.

Type B charge-generating compounds include inorganic compounds such as valized cadmium, cadmium selenide, zinc oxide, zinc sulfide, titanium dioxide (% of rutile type), and trigonal selenium. For example, Sudan Red, Chlordiano Blue J-A-/19/I-A°-shi≦-r';>'M4-USu'i3tgshi! i-? /-
? ? g+1 publication, Japanese Patent Application Publication Shoj≠-273r, Japanese Patent Application Publication Sho Tough-1320ri No. 1, Japanese Patent Application Publication Sho! Disazo pigment described in ♂-/236g/ publication etc., @Kaisho! 7-Hiroshi/14t
Trisazo pigments, Algol Yellow, Pyrenequinone, Indanthrene Brilliant Violet) LR as described in Publication No. 2, Japanese Patent Application Publication No. 2003-130010, t7-//13≠J, etc.
Quinone pigments such as P, -! : Indigo pigments such as rylene pigments, indigo and thioindigo; Bisbenzimidazole pigments such as India Fast Orange toner; phthalocyanine pigments such as copper phthalocyanine; quinacridone pigments;
A/traginone pigment, naphthoquinone pigment, squalium pigment, U.S. Pat.

Special Public Shota T-77 Publication, Samurai Kaisho Geta-/-23/
There are cyanine pigments and the like described in Japanese Patent Publication No.

The aforementioned A and B types of electrophotographic photoreceptors containing the azine compound according to the present invention are used by a method in which the azine compound itself does not have a film-forming ability, so it is dissolved in a solution together with a binder, coated, and dried.

As the binder, it is preferable to use a film-forming polymer that is hydrophobic, has a high dielectric constant, and is electrically insulating. Examples of such polymer imaginary combinations include first-order ones, but of course they are not limited to these VCs.

Polycarbonate! Reester, methacrylic resin, acrylic resin, polyvinyl chloride, polyvinyl chloride IJf, polystyrene, polyvinyl acetate, styrene.
Butadiene copolymer, vinylidene chloride-acrylonitrile copolymer, vinyl chloride-vinyl acetate copolymer, vinyl chloride-vinyl acetate-maleic anhydride copolymer, silicone resin, Noricon-Alkyd Jugetsu L phenol-formaldehyde resin, Styrene-alkyd resin, poly-N
-Vinylcarbazole These binders can be used alone or as a mixture of λ birch or more.

The amount of binder is from 0.2 parts by weight to 2 parts by weight of the compound of the present invention in both A and B type photoreceptors.
It is used in a range of 0 parts by weight. The amount of binder is 002
If it is less than 20 parts by weight, the properties of the photosensitive layer as a film will be weakened, and if it exceeds 20 parts by weight, the sensitivity of the photosensitive layer will be poor. Preferably, the weight range is from o, r to ioM.

In the A-type photoreceptor, the amount of the sensitizing dye ranges from o,oootMH parts to o,rM parts by weight, preferably from 0.00/part by weight to 0.
The range is 1 part by weight.

Further, the amount of the electron-withdrawing compound is 10 parts by weight, preferably 0.1 parts by weight, based on the compound of the present invention/part by weight.
It is used in a range of 1 part to 1 part by weight.

Of the B type photoconductors, F? The amount of the charge-generating compound used in the composition ranges from 2 parts by weight to 2 parts by weight, based on the compound of the present invention/part by weight. be.

In the B type laminated photoreceptor, the charge generation layer is per part by weight of the charge generation compound! Thickness of the photosensitive layer below the M edge part: 1
-j 7 to 30 for both A and B type photoconductors
The micron range is preferred.

In a type B laminated photoreceptor in which the photosensitive layer is composed of two layers, a charge generation layer and a charge transport layer, the charge generation layer is 0.
The charge transport layer ranges from 7 to 30
Can be used in the micron range.

Coating methods used to form the photosensitive layer of the present invention include a broad coating method, a wire per coating method, a spray coating method, a dip coating method, a bead coating method, an air knife coach-in method, and a curtain coating method. Conventional methods can be used.

The solvent used in forming the photosensitive layer of the present invention includes many useful organic solvents. Typical examples include aromatic hydrocarbons such as benzene, naphthalene, toluene, xylene, mesitylene, and chlorobenzene, ketones such as acetate, 2-butanone, and halogenated compounds such as methylene chloride, chloroform, and ethylene chloride. Cyclic or linear ethers such as aliphatic carbon,
Alternatively, a mixed solvent of these can be used.

In addition, when applying a charge generating compound, use an amine solvent such as ethylenediamine, diethylenetriamine, or tridimethylaminomethylphenol to facilitate dispersion.
An amide solvent such as N,N-dimethylformamide can be added to the coating solvent.

The photosensitive layer of the present invention can contain various additives that increase the plasticity of the photosensitive layer and improve the film strength. Such additives include diphenyl.

Diphenyl chloride, O-terphenyl, P-terphenyl, dibutyl phthalate, dimethyl glycol phthalate, dioctyl phthalate, triphenyl phosphoric acid, methylnaphthalene, benzophenone.

Chlorinated paraffin, lauryl thiopropionate,!
,! - dinitrosalicyl i, various fluorocarbons,
Silicone oil, silicone rubber or dibutylhydroxytoluene, 2,2'-methylene-bis-(6-1
-butyl-Hiro-methylphenol), α-tocopherol, 2-t-octyl-! -chlorohydroquinone,
, 2. Examples include phenolic compounds such as t-di-t-octylhydroquinone.

The conductive support constituting the photoreceptor of the present invention may be a paper or plastic support made conductive by applying a conductive compound such as indium oxide or cuprous iodide or a thin metal layer to the surface, or a plastic support as required. Depending on the requirements, any metal plate plated or vacuum-deposited with palladium, aluminum, or the like, or an aluminum plate may be used.

In addition to the above-mentioned polymer binder, casein and gelatin can be used as materials constituting intermediate layers such as an adhesive layer and a barrier layer, which are provided as needed.

Starch, polyvinyl alcohol, polyvinyl acetate.

In addition to ethyl cellulose, carboxymethyl cellulose, etc., patent application 1974/ri 4t/tata, patent application 1977-22
An organic polymer compound consisting of a ternary system or a metal oxide such as aluminum oxide described in the specification of No. 3302 is used.

The electrophotographic photoreceptor of the present invention is not only used in Vi'Th-child photocopiers, but also widely used in electrophotographic applications such as solar cells, microfilms, laser printers, CRT printers, and electrophotographic plate-making systems. be able to.

This will be explained more specifically based on all the embodiments of the present invention, but 1
The present invention is not limited to the following examples unless it exceeds the gist thereof. In addition, in the following examples, all parts indicate the part where M is placed.

Example 1゜7! Bisazo pigment 5 with the following structure is placed on a conductive support made of μ polyethylene terephthalate film with aluminum vapor-deposited.
A solution of 5 parts of polyester pine resin (trade name: Byron, 200. manufactured by Toyo Rayon ■) dissolved in 72,750 parts of tetrahydro was dispersed for 1 hour in a toshiaker, and then applied with a wire to give a film thickness of 0.7μ. A charge generation layer was formed.

(Next to bisazo pigment, % azine compound (1 to 7 parts, polycarbonate (
Product name Lexan/21. Engineering Plastic ■) 7 parts methylene chloride θ part and ethylene chloride 1 part
A coating solution dissolved in 0 parts of a mixed solvent is applied onto the charge generation layer using a wire bar, and the charge generation layer and the charge transport layer are separated.
A laminated photoreceptor consisting of layers with a film thickness of 3 μm was prepared. No crystal precipitation due to the azine compound was observed on the surface of the photoreceptor.

This photoreceptor was tested using an electrostatic copying paper tester (manufactured by Kawaguchi Denki ■, 5P).
After setting the initial potential (■0) of the photoconductor surface to -trov by corona discharge of -p2 (type) -tkv, irradiation with tungsten light was performed, and the potential of the photoconductor surface was changed! The exposure amount required to attenuate Ochi and the half-reduced amount of light (E5o) were measured. F
'so was ko, j1ux-sec. Also, when measured after performing the charging and miscellaneous light process 1000 times in succession, the result was V.

Ha-&4! jv, E50 is 2, II 1ux-sec
There were no major changes compared to the first time.

Example 2. ~4 A laminated photoconductor was prepared in the same manner as in Example 1 except that azine compounds (3), (6), and (101) were used instead of azine compound (1), respectively, and half-decreased exposure (E5.) The results are shown in Table 1.

River comparison example 1. ~3 Example 1'1: A comparison compound other than the azine compound according to the present invention (A-/
), (A-u), and (A-3) were used, but a photoreceptor was produced in the same manner as in Example 1.

Comparative Compound (A-2) (A-J) As is clear from Example 1 and Comparative Example 1% 2, it is an asymmetric azine compound synthesized from da,v'-di(N-disubstituted amine)benzophenone according to the present invention. Compounds are ≠, ≠“
-(N-Disubstituted amine) Compared to azine compounds synthesized from carbonyl compounds other than benzophenone, it has better sensitivity and excellent charging characteristics after re-recycling.

This indicates that the compound according to the present invention is the comparative compound (A-/), (
This is because it has one more N-disubstituted amino group than A-λ, so the highest occupied level of the compound becomes higher, resulting in improved hole injection efficiency from the charge generation layer to the charge transport layer. it is conceivable that.

Furthermore, as is clear from Example 1 and Comparative Example 3, ≠l≠
The symmetric azine compound synthesized from '-di(N-disubstituted amine) benzophenone has lower sensitivity and poor solubility than the asymmetric azine compound according to the present invention, resulting in the precipitation of rc crystals on the surface of the photoreceptor. It has the disadvantage that it is easy to

Example 5 1 part by weight of azine compound (1) according to the present invention, ≠-(4
4-(N-2-chloroethyl, N-2-cyanoethyl)
A coating solution was prepared by dissolving 0.0/part of steryl chloride 2,6-di-t-butylthiopyrylium fluoroborate and t and z parts of polycarbonate (Lexan 1Ji) in a mixed solvent of methylene chloride≠θ parts and 10 parts of ethylene chloride. did. This coating solution was applied with a wire spar onto a transparent conductive film on which indium oxide doped with soot was deposited on the surface of a polyethylene terephthalate film, and dried to obtain a photoreceptor having a photosensitive layer having a film thickness of jμ.

This photoreceptor was charged to +2 jOv using the same device as in Example 1, and the Eso was measured to be /01 ux-sec.

Example 6. A photoreceptor was prepared in the same manner as in Example 5 except that 81 to 81 azine compound (1) was used, and the sensitivity was measured. The results are shown in Table 3.

Table 3 Comparative example 4. ~6゜Azine compound (A-g) (A-
(y) (A photoreceptor was prepared in the same manner as in Example except that A-1 was used.

Comparative Compound (A-44) (A-Y) (A-1) The band'i and @ properties of this photoreceptor were measured by the methods of Practical Mu Example 7 and Mu Example 1. The results are shown in Table 1. The sensitivity was lower than in Example 7.

Table 1 In addition, crystals were deposited on the photoreceptor surface of the photoreceptor prepared in Comparative Example 6 after being left at room temperature for one week.

Example 9 1 part of bisazo pigment with the following structure, an azine compound (313
m, and 1 part of polycarbonate (Lexan/21) were added to 7725 parts of methychloride.

This was shaken for 1 hour using an intoshaker to prepare a coating solution. This coating solution was coated with a wire paper onto a conductive support made of a polyethylene terephthalate film on which aluminum was vapor-deposited, and dried to obtain a single-layer type photoreceptor having a photosensitive layer having a thickness of ioμ.

(Bisazo Pigment) Using the same apparatus as in Example 1, this electrophotographic photoreceptor was charged to +1ljOv by +jkv corona discharge and exposed to tungsten light. Half-reduced exposure amount (Eso
) was measured and found to be lux·sec.

Furthermore, even if the two steps of charging and exposure are repeated 1000 times, E50 remains.
changed little.

Example 10 1 part of bisazo pigment used in Example 9, 2 azine compounds
1 part and 6 parts of m-cresol formal human resin to 30 parts of ethylene glycol monomethyl ether,
Grind this in a ball mill.

Mix and apply this coating solution to approximately 0. It was applied using a wire round rod onto a Ztmm thick grained, anodized and sealed aluminum plate, and dried for 10 minutes at RO 0C for 1 day.

A sample with a thickness of about 6 μm was prepared.

Next, corona discharge was applied to this sample in a dark place so that the surface potential became 5ooVvc, and the negative image was exposed to tungsten light (/θ0 lux seconds). After reversal development was carried out using the following products:

A very clear positive image could be obtained on the original printing plate.

This printing original plate was immersed for one minute in a 10-fold diluted etching solution DP-/(manufactured by Fuji Photo Film Co., Ltd.: sodium silicate aqueous solution), and the photosensitive layer was removed from the areas to which toner was not attached (non-image areas). was dissolved and removed. As a result, the pigment in the non-image area was easily removed together with the binder, and a printing plate with a clear image could be formed.

Claims (1)

[Claims] (1) An electrophotographic photoreceptor characterized by having a photosensitive layer containing a compound represented by the following general formula (1). However, in the formula, R1, R2, R3, and R4 represent a radical or an unsubstituted alkyl group, an aralkyl group, an aryl group, or a residue that forms a cyclic amine group together with a nitrogen atom; Unsubstituted alkyl groups, excluding a. R6 represents a ralkyloxy group, an aryloxy group, a halogen atom, or R6 represents an atom necessary to form a heterocycle together with R7 or R8 and the benzene ring to which they are bonded.1-0R7 and R8 may be the same or different, hydrogen, alkyl group, alkoxy group,
It represents a halogen atom or represents an electron necessary to form a heterocycle with t'1tR6.