JPS6256971A - Electrophotographic sensitive material - Google Patents

Abstract

PURPOSE:To obtain the titled material having a high sensitivity especially at a wavelength range of a semiconductor laser by incorporating at least one kind of the compds. shown by the formula to an organic photoconductive substance. CONSTITUTION:The titled material comprises the compd. shown by the formula to the organic photoconductive substance. In the formula, R1, R2 R4 and R5 are each a hydrogen atom or a substd. or an unsubstd. alkyl group, R3 is a hydrogen atom, a halogen atom or a substd or an unsubstd. alkyl group, R1-R5 are each a hydrogen atom or an alkyl group, and may be same to or different to each other. A and B are each an oxygen atom or a sulfur atom, X is anion. And then, the electrophotographic film used in the titled material is prepared by coating the titled material on the polyethylene terephthalate film provided a deposited film composed of an indium oxide thereon followed by drying it. Thus, the prescribed film gives the max. adsorption at a range of oscillating the laser.

Description

DETAILED DESCRIPTION OF THE INVENTION "Field of Industrial Application" The present invention relates to a highly sensitive electrophotographic material mainly composed of an organic photoconductive substance, and particularly to an electrophotographic material exhibiting high sensitivity in the wavelength region of a semiconductor laser.

"Prior Art" In recent years, electrophotographic systems using semiconductor lasers as light sources have been actively developed. Semiconductor lasers are He-Ne and A
It is smaller and lower cost than gas lasers such as R.
It has great advantages such as direct modulation, but the oscillation wavelength is 2! It was often θnm or more. Therefore, the photoreceptor used in this system must have absorption at 7j 0 nm or more and exhibit high sensitivity, and various sensitizing dyes and the like are being developed. However, organic compounds that absorb in the long wavelength range are generally unstable with respect to heat and humidity, causing problems in manufacturing and handling, and furthermore, photosensitive materials made using them tend to deteriorate over time. is significantly,
Many of them lost their function as photoreceptors when stored for a long period of time. In addition, especially in the case of P-IJIJ-based dyes, when the structure is changed, such as by introducing an aromatic group into the P-IJIJium ring, in order to increase absorption at longer wavelengths, sub-absorption occurs in the short wavelength region, and the translucent electron When used in photographic film, the film sometimes took on a yellowish tinge. Furthermore, such films suffer from significant optical fatigue, and once exposed to light, it takes a considerable amount of time to recover the sensitivity.

"Problems to be Solved by the Invention" The first object of the present invention is to
An object of the present invention is to provide an electrophotographic material containing a Jium compound and having high sensitivity.

A second object of the present invention is to provide an electrophotographic photosensitive material that is durable against heat and humidity.

A third object of the present invention is to provide an electrophotographic material that has main absorption in the oscillation wavelength region of a semiconductor laser and exhibits high sensitivity.

The fourth object of the present invention is a short wavelength region (4toθ~!0θn
The object of the present invention is to provide an electrophotographic light-sensitive material having substantially no sub-absorption in (m).

"Means for Solving the Problems" That is, as a result of intensive research, the present inventors solved the above problems by using an electrophotographic material containing an organic photoconductive substance and at least one compound represented by the following general formula (I). I was able to solve the problem.

General formula (I) In the formula, R1+ Rz + R41Rs represents a hydrogen atom, a substituted or unsubstituted alkyl group, R3 is a hydrogen atom,
Indicates a halogen atom or a substituted or unsubstituted alkyl group. The hydrogen atoms or alkyl groups of R1, R2, and Rs 1R41R5 may be the same or different.

A and B represent an oxygen atom or a sulfur atom, but they cannot be the same at the same time. X represents an anion.

In addition, the alkyl group of R1, R2, Ra lR4, and Rs is preferably an alkyl group having 7 to 72 carbon atoms, and specifically, methyl, ethyl, n-propyl, 1so-propyl, n-butyl, 5ec-butyl. , tert-butyl, n
-amyl, n-hexyl, n-heptyl, n-nonyl,
n-)'y' syl, -1ethylhexyl, fluoromethyl, chloromethyl, bromomethyl, trifluoromethyl, perfluoroalkyl, methoxymethyl, cyanmethyl, methylthiomethyl, and the like.

In addition, as an anion of X, specifically, verchlorate,
Tetrafluoroborate, iodide, chloride,
Bromide, sulfate, iodide, p-
Examples include toluene sulfonate.

In the compound used in the present invention, a tert-butyl group (hereinafter referred to as tert-B
(denoted by the u group) plays a role in improving the stability and solubility of the compound.

Furthermore, A and B are a combination of sulfur atoms and oxygen atoms.

By doing so, the absorption maximum wavelength can be set to around 7 r Onm. R and -R5 have the role of finely adjusting the absorption maximum wavelength as desired.

Examples of PIJ17ium-based compounds having main absorption in the vicinity of 7/Onm include the trimethinethiapyrylium dye disclosed in JP-A No. 7-/41264TJ (corresponding to U.S. Patent No. 327./49); Tokukai Akira! Tar 4t/3
Thiapyrylium dyes disclosed in No. 63 are known, but all of them have a phenyl group on the top of the thiapyrylium, and therefore have sub-absorption in a short wavelength region (4t00-jθQnm). Furthermore, in the former case, when the coated material is exposed to solvent vapor, aggregation easily occurs, causing a change in absorption maximum and a corresponding change in electrophotographic properties. Such undesirable effects do not occur in the compounds used in the present invention due to the effect of the tert-Bu group.

Next, typical examples of the compound represented by the general formula (I) used in the present invention are shown below, but the present invention is not limited thereto.

Compound-(I) Compound-(2) α04e Compound-(3) 1O4e Compound-(4t) α04e Compound=<3) Compound-(6) αo4Fj Compound-(2) Compound-(?) Compound-(wa) Of O4 Compound-(I0) Compound-(//) Compound-(/, 2) αO4 Compound-(/3) Since the amount of the pyridium-based compound used in the present invention is used to sensitize the organic photoconductor, The amount varies depending on the type of organic photoconductor, but in general, it is 0.0/% to 700% by weight of the organic photoconductor, preferably θ,
/H to 30%.

The pyrylium compound used in the present invention is, for example, pyrylium compound.

≦-Di-tert-zoteruder methyltheapyrylium salt is reacted with an equimolar amount of /-anilino-3-phenyliminopropane, followed by a further equimolar amount of 2.6-tert.
Obtained by reaction with t-butyl-gumethylpyrylium salt C2. This reaction is preferably carried out in acetic anhydride in the first step and in acetic anhydride in the second step in the presence of a base such as anhydrous sodium acetate. In the first step reaction, the amount of acetic anhydride was ~20 ml per 2.6-di-tert-butyl-Hiro-methylthiapyrylium salt/g.

Preferably it is 2 to 10 ml. The reaction temperature is lθ0,
to reflux temperature, preferably around 10θ0C. The reaction time is 7 minutes to 7 hours, preferably 70 minutes.
30 minutes. It is also possible to isolate the intermediate prior to carrying out the second step reaction. The intermediate can be isolated by diluting the first-stage reaction mixture with an organic solvent such as ether that is a poor solvent for the intermediate, and crystallizing the intermediate. In the second stage reaction, the amount of anhydrous sodium acetate is .

tert-butyl-g-methylpyrylium salt 1
It is preferable to use an amount equivalent to 2 to 3 moles. The reaction time and reaction temperature are the same as those in the first stage.

Next, a method for synthesizing the pyrylium compound used in the present invention will be explained using a synthesis example.

In addition, 2.6-tert-butyl-gumethyltheapyrylium salt is JP-A-Shojt-/4tjtθ, JP-A-Kokai Shoj≦-
/4tjt/ etc. C2 was synthesized by the method described (2).

Synthesis Example-/ (2, Easy synthesis of tert-butyl-guethylpyrylium perchlorate) In a mixture of tin tetrachloride (I04t, λg, 0, aamole) and piparoyl chloride (rij-jg4 θ, ♂ Omole) While stirring under water cooling, add Komei Coop CX-
! Nia (30,/g, 0,, aamole) was added dropwise and reacted. After the completion of the dropwise addition/hour, stirring was continued, the reaction mixture was poured into an ice-water ROOG containing 6 og of ≦0% perchloric acid with vigorous stirring, and stirring was continued for an additional 7 hours. The precipitated solid was collected and recrystallized with ethyl acetate/2θml to obtain 4-di-tert-butyl-g-ethylpyrylium perchlorate as white needle-like crystals with a melting point of /lO-/J4t'C.

(Yield λ, 52g Yield 3./%) Elemental analysis Molecular formula C15H2505α1CHα Calculated value (%) 7 cores, /bu 7.1! //, 0! Experimental value (chi) jl, ri 0 7. lt //, 0 synthesis example-
2 (Synthesis of compound -(=)) 2.6-sheet tert-
Butyl-goomethyltheapyrylium perchlorate (2
, agsO”θ/mole), /-anilino-3-phenyliminoprohane (2,agsO0θ/mole)
were mixed well, and jmJl of acetic anhydride was added. Mixture/
After heating to θ00C and stirring for 70 minutes, synthesis example-
Pyrylium salt synthesized with / (,?, Jg, 0.0/mo
le), anhydrous sodium acetate (/, 7g, 0.0.2
4 tmmol) was added thereto, and stirring was continued for an additional 30 minutes. 10 ml of ethyl acetate was added to the reaction mixture cooled to room temperature, and stirring was continued under water cooling. The precipitated crystals were collected by filtration, washed with water, dried, and then recrystallized from a mixed solvent of ethyl acetate and ethanol (3:1) to obtain compound (2) with a melting point (decomposition point) of 23! ~23t
Obtained as greenish-gold crystals of 0c. (Yield 2.0
/g yield j4t, 7chi) Elemental analysis Molecular formula C32H47α105S1cHα
S Calculated value (ch) tt, 3t ♂, /ta 6. /Ko! ,j3
Experimental value (%), <4. / Ko♂, 2! ni, // ta, gu♂
Synthesis Example 3 (Synthesis of Compound) -N-butyllithium (/) was added to an anhydrous THF solution of J,4-di-tert-butyl-r-pi 1:17 (<t/1 mg% 2 mmol) cooled to 2Q0C.

/7M hexane solution/ , 29ml, , 2, 4tm
mol) was dropped and reacted. After 7 hours, the reaction mixture was diluted with 6 ml of perchloric acid aqueous solution! The precipitated oily substance was extracted with 4 toml of methylene chloride. Na2SO
After drying in step 4, the solvent is distilled off and the mixture is removed.
t-Butyl-a-n-butylpyrylium verchlorate was obtained as a white solid. (Yield t4t4tmg,
Yield: 7/, /%) Next, using this pyrylium salt, the same procedure as in Synthesis Example 1 was carried out to obtain the compound -(-) as greenish gold crystals (melting point: 2//-). 2
/0C (decomposition)) The improved electrophotographic material of the present invention comprises at least a support and a photosensitive layer.

The support used in the present invention requires conductive treatment. Specific conductive treatments include aluminum, gold,
/9 A method of vapor-depositing a metal such as Radium or Injunim, or a method of vapor-depositing a metal oxide such as In2O3,5noz, or a method of dispersing metal powder or a metal oxide such as 5no2 in a binder polymer and applying it, or Examples include a method of dissolving and applying an organic onium salt compound together with a binder polymer, and a method of applying an acetonitrile solution of iodized steel.

As the organic photoconductive substance used in the electrophotographic photosensitive material of the present invention, many conventionally known organic photoconductive substances can be used.

Examples of polymers include the following:

(I) U.S. Patent No. 3,03? , 161 specification, JP 74t-/θri 44, JP 412-/ri 2t1, 4t-ko 212JO, (2) JP Shoda 3-// Polyvinylpyrene, polyvinylanthracene, polycovinyl<t-(4t'-dimethylaminophenyl) described in Go No. 74 and Japanese Patent Publication No. 4t3-/9/2.
-2-phenyl-oxazole, poly-3-vinyl-N
- Vinyl polymers such as ethylcarbazole, (3) Polymers such as polyacenaphthylene, polyisodene, copolymers of acenaphthylene and styrene, etc. described in Japanese Patent Publication No. 4tJ-'/9/3, (4) % Kimiaki! t-/394t
Pyrene-formaldehyde m fat described in θ issue etc.,
Condensation resins such as brompyrene-formaldehyde resin, ethylcarbazole-formaldehyde resin, etc., (5) JP-A-74-90113 and JP-A-74-90113 and JP-A-Sho jt-/l/! jO
Various triphenylmethane polymers described in the above publication.

In addition, the following can be mentioned as low molecular weight compounds.

(6) Triazole derivatives described in U.S. Patent No. 3/2/7, etc., (7) Oxadiazole derivatives described in U.S. Pat. 8) Special Public Service 1977
-Imidazole derivatives described in Publication No. 16094, etc. (9) US Patent No. 3tl! No. 402, No. 3♂Ko 29, No. Jj4t2j4t4, Special Public Show No.4t! −j
JT issue, Tokko Akira! t/-10973, Japanese Patent Application Publication No. Shoj1-9
No. 32241, Tokukai Shoj! -/71Oj, Tokukai Shojt
-411411, Tokukai Sho! ! -10r≦62, JP-A-1! -/jOtsu9j3, JP-A-Shojd-34474, polyarylalkane derivatives described in publications, α1 U.S. Patent No. 3170729, U.S. Patent No. DAKO 7
/ No. 714, Tokukai Sho 1! -1106g issue, Tokukaisho! −
No. 11041, Tokukai Showa 4t? -10j! No. 32, Tokukai Akira! ! --j10♂4, Tokukai Akira! Go-20061, Tokukai Sho! 6-♂114t/, Tokukai Shoj7-+tjj4t!
No., JP-A-Sho j4t-//, 2,4j-7, JP-A-Sho ni j-
Pyrazoline derivatives and pyrazolone derivatives, αD, described in US Patent No. j6114t04, Japanese Patent Publication No. J-/-10/θ! No., Tokukai Akira! Goo t34tjj issue,
Tokukai Akira! Gu//θr3bu issue, Tokukai Akira! Gu//? ? ,
2j No. 2j, Special Publication Showa 4t-1 No. 3272, Special Publication No. 4t7-.
2r33 is a phenylenediamine derivative described in the specification, gazette, etc., a3 US Patent 3! Otsu 74t!
θ issue, special public Showa 4t? -31702, West German patent (DA
S)///Qj/♂, US Patent No. 31♂0703,
US Pat. No. 3,241,0397, US Pat. No. 3trr, US Pat. j-/4t4t2JO, JP-A-Shoj6-1/ri7
No. 32, Special Publication Sho J9-27!72, Japanese Patent Publication No. Sho J-4-2
Arylamine derivatives that have been described in the specification of No. 2DA No. 37, publications, etc., αKEN US Patent 3! Koro! amine-substituted chalcone derivatives described in the specification of Q/, α4 N,N-bicalpadil derivatives described in the specification of US Patent No. 3!4t2j4tt etc., α9 oxazole derivatives described in the specification of US Patent No. 32!7203 etc.舖 Steryl anthracene derivatives described in JP-A ShojJ-4tj2j4, etc., αD Fluorenone derivatives described in JP-A Shojg-//θ/37, etc., αQ U.S. Patent No. 37/7' lt2 issue, Tokukai Akira! Kuj
ri/4t3 (corresponding to US Patent No. 4t/j09t!r7), JP-A-Sho! No. j-12063, Japanese Patent Application Publication No. Shojj-120
No. 44, Tokukai Shojj-4t6750, Tokukai Sho Jr!
−? '4ttr issue, Tokukai Akira! ? -7/3! No. O, JP-A No. 7-/4t/74-t, JP-A-77-J (t,
Hydrazone derivatives disclosed in 2Q& specification, publications, etc. (I9 Japanese Patent Publication No. 39-111414, Japanese Unexamined Patent Publication No. 39-7 Hari θ (U.S. Pat. No. 41.26!, 990; 2 correspondence),
U.S. Patent No. 04t7, Tag Publication No. 9, −
Examples include benzidine derivatives disclosed in specifications and the like.

These organic photoconductive substances are preferably used in the photosensitive layer in an amount of 20 to 99% by weight.

When the organic photoconductor is a low-molecular compound, a high-molecular compound having suitable film properties can be used as a binder. Specifically, polyamide, polyurethane, polyester, epoxy resin, polyketone, styrenic polymer and copolymer, poly-N-vinylcarbazole, polycarbonate, polyester carbonate, polysulfone, vinyl chloride resin, vinylidene chloride resin, vinyl acetate resin. , various polymeric compounds such as acrylic resin. When the organic photoconductor is a polymer compound,
Although it has film properties by itself, the above-mentioned polymer compound may be added if necessary.

The amount of the binder added varies depending on the type of organic photoconductor, but in the case of a low-molecular organic photoconductor, it is desirable to use the binder in a weight ratio of jO'1s-2θθ to the organic photoconductor. When the organic photoconductor is a polymer, it is desirable to use it in an amount of /% to 0%.

A chemical sensitizer can be used in the recording material ζ2 of the present invention, and examples of the chemical sensitizer include electron-withdrawing compounds such as trinitrofluorenone, chloranil, and tetracyanoethylene; '-6! G3ri, Tokukai Shoj♂-
Examples include the compounds described in 10 and 23.

The electrophotographic material of the present invention may contain known structure agents, plasticizers,
Dyes, pigments, etc. may be contained within the range that does not impair the characteristics of the electrophotographic material of the present invention.

Cyanethyl cellulose, nitrile rubber, as reinforcing agents
Bisphenol A polycarbonate, linear polyester, styrene-butadiene copolymer, vinylidene chloride
Acrylonitrile copolymers and the like can be used.

As a plasticizer, chlorinated biphenyls, epoxy resins, triphenylmethane compounds, coumaron resins, low molecular weight xylene resins, etc. can be used.

In addition, the electrophotographic light-sensitive material of the present invention includes
- Particular plasticizers described in Japanese Patent Publication No. 46263, silane coupling agents, curing catalysts and/or crosslinking agents described in Japanese Patent Publication No. 67-/94t23, C2, Japanese Patent Application Publication No. 1983-1996
-/-t! "The fluorine-containing surfactant described in Japanese Patent Publication No. 7021, the Lewis acid described in Japanese Patent Publication No. Sho 17-/94T24, and the electron-donating substance described in Japanese Patent Publication No. Sho J-7-/97♂C, etc. I can do it.

When producing the electrophotographic light-sensitive material of the present invention, a polymeric organic photoconductor, a solvent selected from benzene, toluene, xylene, chlorobenzene, dichloromethane, dichloroethane, trichloroethane, cyclohexanone, tetrahydrofuran, dioxane, etc., and a mixed solvent thereof,
A solvent that dissolves or disperses both the sensitizing dye and optionally added components can be used.

The photosensitive material according to the present invention can be obtained as follows.

To prepare a photosensitive material, a photoconductive substance, the pyrylium dye of the present invention, and optionally added components are dissolved or dispersed in a solvent in a desired ratio, coated on a conductive support, and dried. Alternatively, a self-supporting film can be obtained by melt-coating the above-mentioned components onto a conductive support, or by preparing a photosensitive thin film from a solution or by a melt-extrusion method. Furthermore, for coating, a known coating surfactant may be included in the coating solution.

The electrophotographic material of the present invention may have a surface protective layer.

An example of the surface protective layer is a layer of a binder resin containing fine particles. Binder resins used include polyester carbonate, polysulfone, polyether, polyester, polycarbonate, polyamide, polyimide, polyurethane, acrylic ester polymers and copolymers,
Methacrylic acid ester polymers and copolymers, styrene resins, polyvinyl acetals, polyvinyl carbazole, vinyl chloride resins, vinylidene chloride resins, chlorinated polyolefins, vinyl acetate resins, alkyd resins, xylene resins, Kent resins, celluloses However, it is not limited to this. These resins may be used alone or in combination.
More than one species can be used in combination.

Various types of fine particles can be used as the fine particles. For example, inorganic insulating fine particles such as silica, calcium carbonate, mica, clay, and boron nitride, metal oxides such as titanium oxide, aluminum oxide, magnesium oxide, zinc oxide, tin dioxide, and bismuth oxide, zinc stearate, and calcium stearate. Examples include, but are not limited to, long-chain organic acid metal salts such as zinc laurate, organic fine particles such as polypropylene, polyethylene, polyamide, polyvinylidene fluoride, and polytetrafluoroethylene. Among these fine particles, silica, aluminum oxide, and titanium oxide, which can be easily dispersed in 10%, can be preferably used.

In the electrophotographic material of the present invention, an intermediate layer may be provided between the support and the photosensitive layer or between the photosensitive layer and the surface protective layer for various purposes (for example, to improve adhesion), if necessary. It's okay.

The electrophotographic material of the present invention may be provided with a layer on its back surface for improving properties such as slip properties, charging properties, anti-blocking properties, and antinolation properties.

"Example" Examples of the present invention are shown below, but the present invention is not limited thereto.

Example/N,N'-diphenyl-N,N'-bis(3-
methylphenyl) -(/, /'-biphenyl] -da,4t'-diamine 0.Jg Compound of the present invention -(=), 2.rtrng(txl
o-amole) Polycarbonate (Product name: "Panlite/? θ0" manufactured by Teijin ■) 0.7g linear polyester resin (Product name: "Byron 200" manufactured by Toyobo ■) θ, θ/gbu 4tm
g dichloromethane 3 ml dichloroethane 1 ml A photosensitive solution having the above composition was prepared, and then coated on a 700 μm thick polyethylene terephthalate film having a vapor-deposited indium oxide film using a wire, F-, and dried. thickness? ,
An electrophotographic film with a 7 μm photoconductive layer was obtained. As shown in Figure 7, this film had an absorption maximum within the C: semiconductor laser oscillation region (2/♂nm), and the absorption in the short wavelength range (4tθθ~jQ0nm) was practically not a problem. .

Next, the obtained electrophotographic film was tested using a copying paper tester sp-
Using gco/(manufactured by Kawaguchi Denki ■), the sample was statically charged with a corona at +7.7 kV and exposed to monochromatic light of 7 r r nm to examine its electrophotographic properties.

The characteristic charge retention ability was determined by measuring the potential 6θ seconds after corona charging in a dark place and determining the residual rate (%) of the initial potential.

In addition, the sensitivity is the exposure amount (Eso) where the potential before exposure becomes //10 (=) due to optical attenuation and the exposure amount (E9G
) was sought.

The charge retention power shows a good value of 90%, and the sensitivity is at electric field strength θ, 71X/θ6■/cm? ! erg/cm2
(E51)) jwo/lHg7cm2 (E90), which was extremely sensitive.

Also, when using tungsten light (4 tlux) as a light source, the charge retention catalyst O%E 5cl 261ux-se
c.

Eg□'/7.2/ux-sec (electric field strength 0.
7! ×106 V/cm), which was a good value.

Next, use the above electrophotographic film! After being left at 0°C and zo4RH for IO weeks, absorption maximum and electrophotographic properties were examined, and almost no change was observed.

Example Using the compounds (I), (j), and (4t) of the present invention, electrophotographic films were obtained by carrying out the same operations as in Example. The results regarding absorption maximum and electrophotographic properties of each film are shown in Table 7C-2.

As is clear from Table 1, all of these films have a small absorption maximum within the oscillation region of the semiconductor laser and have good electrophotographic sensitivity. Next, these films were left for 70 weeks under the conditions of jo'C and tro%RH, and the above-mentioned properties were measured, and there were almost no changes from those shown in Table 1.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 7 shows the absorption spectrum of the electrophotographic film of Example/in the visible to near infrared region.

Claims (1)

[Scope of Claims] An electrophotographic light-sensitive material comprising an organic photoconductive substance and at least one compound represented by the following general formula (I). General formula (I) ▲There are numerical formulas, chemical formulas, tables, etc.▼ In the formula, R_1, R_2, R_4, R_5 represent a hydrogen atom, a substituted or unsubstituted alkyl group, and R_3 represents a hydrogen atom, a halogen atom, a substituted or unsubstituted alkyl group. Indicates a substituted alkyl group. The hydrogen atoms or alkyl groups of R_1, R_2, R_3, R_4, and R_5 may be the same or different. A and B represent an oxygen atom or a sulfur atom, but they cannot be the same at the same time. X represents an anion.