JPH0361952A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain high sensitivity and flat spectral characteristics in the wavelength region of beams emitted from a laser diode by combining a specified electric charge generating material and a specified charge transfer material. CONSTITUTION:The charge generating layer contains a phthalocyanine pigment represented by formula I as much as possible in order to obtain sufficient light absorbance and the charge transfer layer is formed by dissolving a fluorene compound represented by formula II together with a proper binder and coating with it, and in formulae I and II, R1 is H, alkyl, halogen, or the like; m is an integer of 1 - 4; M is a metal atom except alkali metals; Y is absent when M is divalent, when M is trivalent, Y is halogen, alkyl, or the like, and when M is tetravalent, Y is an O or halogen atom; each of R2 and R3 is alkyl; and each of R4 - R6 is H, alkyl, or the like, thus permitting sufficient high sensitivity and flatness of spectral sensitivity in the wavelength region of the beams emitted from the laser diode to be obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to an electrophotographic photoreceptor, and more particularly to a laminated electrophotographic photoreceptor having a charge generation layer and a charge transport layer.

[Prior Art] Conventionally, inorganic electrophotographic photoreceptors having a photosensitive layer containing selenium, cadmium sulfide, zinc oxide, etc. as main components have been widely used as electrophotographic photoreceptors.

These materials are not necessarily satisfactory in terms of thermal stability, moisture resistance, durability, etc. Particularly, selenium and cadmium sulfide have limitations in production and handling due to their toxicity.

On the other hand, electrophotographic photoreceptors having a photosensitive layer containing an organic photoconductive compound as a main component have many advantages such as overcoming the above-mentioned drawbacks of inorganic electrophotographic photoreceptors, and have been gaining popularity in recent years.

Such photoreceptors include photoconductive polymers typified by poly-N-vinylcarbazole and charge-transfer polymers formed from photoconductive polymers and Lewis acids such as 2.4.7-)linitro-9-fluorenone. Electrophotographic photoreceptors having a photosensitive layer containing a complex as a main component have already been put into practical use.

However, this electrophotographic photoreceptor is not necessarily satisfactory in sensitivity and durability.

On the other hand, functionally separated electrophotographic photoreceptors, in which the charge generation function and charge transport function are divided into separate substances, have brought about significant improvements in sensitivity and durability, which had been considered shortcomings of conventional organic electrophotographic photoreceptors. Ta.

Such a functionally separated electrophotographic photoreceptor has the advantage that there is a wide selection range of materials for each of the charge-generating substance and the charge-transporting substance, and it is relatively easy to manufacture an electrophotographic photoreceptor with arbitrary characteristics. have.

In particular, as electrophotographic photoreceptors have come to be used not only in copiers but also in laser beam printers, LED printers, etc. in recent years, functionally separated type is suitable.

Various azo pigments, phthalocyanine pigments, polycyclic quinone pigments, cyanine dyes, squaric acid dyes, biryllium ring dyes, and the like are known as charge generating substances.

Among them, phthalocyanine pigments are known to be stable against heat and light and exhibit a deep blue color, and have recently attracted attention not only as pigments but also as organic materials that can be put to practical use as electronic materials and catalysts. There is.

In the field of electrophotographic photoreceptors, many proposals have been made, including US Pat. No. 3,816,118, which proposes the use of phthalocyanine pigments.

Documents regarding high-sensitivity phthalocyanine for electrophotographic photoreceptors include Japanese Patent Application Laid-Open No. 57 (1983), which uses vanadium phthalocyanine.
JP-A-146255, JP-A-62-119547 using dihalogenostinphthalocyanine, and JP-A-59-49544 using titanyloxyphthalocyanine.

Now, as charge transport substances, hydrazone compounds, pyrazoline compounds, stilbene compounds, triarylmethane compounds, arylamine compounds, etc. are known.

These compounds are required to be stable against light and heat, and ozone and N produced by corona discharge.
Examples include: being stable against Ox, nitric acid, etc.; 1) exhibiting high charge transport ability; and 2) having high compatibility with organic solvents and binders.

Examples of combinations of the above-mentioned phthalocyanine pigments and charge transport substances include, for example, Japanese Patent Application Laid-open No. 128948/1983;
JP-A-57-146255, JP-A-58-123
542, JP 60-243660, JP 61-27549, JP 61-109056
Examples include descriptions in publications such as No.

Although electrophotographic photoreceptors made with these combinations have little potential fluctuation during repeated use, many of them have major drawbacks in image characteristics, such as image deterioration due to changes in the usage environment, which poses problems in actual use. It becomes.

[Problem R to be Solved by the Invention] An object of the present invention is to provide an electrophotographic photoreceptor in which a charge generation layer and a charge transport layer are separated, and to achieve sufficient high sensitivity and flatness of spectral sensitivity in the laser diode oscillation wavelength range. By providing an electrophotographic photoreceptor that has a stable potential during repeated use, and exhibiting stable potential characteristics and image characteristics regardless of the usage environment (temperature, humidity). be.

[Means for Solving the Problems, Effects] The present invention provides an electrophotographic photoreceptor in which at least two layers, a charge generation layer and a charge transport layer, are provided on a conductive support, in which the charge generation layer has a charge generation substance formed by the following general formula: The layer containing at least one type of phthalocyanine pigment represented by (I) is excluded, and the charge transport layer has the following general formula (■) as a charge transport material.
The electrophotographic photoreceptor is comprised of a layer containing at least one type of fluorene compound shown in the following.

In the general formula, R1 represents a hydrogen atom, an alkyl group, a halogen atom, a cyano group, or a nitro group, m is an integer of 1.2.3 or 4, M represents a metal atom excluding alkali metals, Regarding Y′8 and n, there is no case where 1M is divalent, and when M is trivalent, Y represents a halogen atom, an alkyl group, or an alkoxy group, n is an integer of 1, and M
When is tetravalent, Y represents an oxygen atom, a halogen atom, an alkyl group, or an alkoxy group, and in the case of an oxygen atom, n
is an integer of 1, and in cases other than oxygen atoms, n is an integer of 2.

In the general formula, R2 and R3 represent an alkyl group, R4 represents a hydrogen atom, an alkyl group, an alkoxy group, or a halogen atom, and R5 and R6 represent a hydrogen atom, an alkyl group,
Represents an aralkyl group or an aryl group.

More specifically, among the above groups, the alkyl group is a group such as methyl, ethyl, propyl, butyl.

Alkoxy groups include methoxy, ethoxy, and propoxy; aralkyl groups include benzyl and phenethyl; aryl groups include phenyl and naphthyl; halogen atoms include chlorine, bromine, fluorine, and iodine.

The metal atoms M include Ti, V, Cr, Fe, Cu,
Zn, Ga% Ai, Pb, Ge, S
Selected from n, In, Co, etc.

Typical examples of charge-generating substances and charge-transporting substances used in the present invention are listed below.

Examples of charge generating substances are Rlm, M, which are parts that change in the basic form.
By writing Y and n.

1 - - - 1- - (1) (2) (3) (4) (5) (6) r 7 ) r j C! P-(8) HI Zn --
P-(9) HI In (J
IF-(10) Br 4
In CJ IF-(11)
HI TiOfP-(12)
C look 4 Ti 0
1F-(13)-0CHs I
Ti01F-(14)H
I Ti CJ, 2F-(15
) HI Ti-0CHs 2F
-(16) HI Ti -0M3
1F-(17)-CM I
V 0 1F-(18)-NOYU I V 0 1
F-(19) HIV 0
1F-(20) HI PbP
-(21) HI Fe --F
-(22) HI C.

P-(23) HI Ge Csu 2F-(24) HI Sn
C) Two charge transport substances (general formula (II)
Fluorene compound shown as ) T-(1) - (2) - (3) - (4) 1(5) 1(6) - (7) - (8) - (9) T-(10) - (l 1) 1 (12) T-(13) T-(14) T-(15) T-(16) 1(1 7) T-(18) T-(1 9) T-(20) T-( 21) - (22) - (23) - (24) Next, the present R1 light electrophotographic photoreceptor will be described in more detail.

The charge generation layer contains as much of the phthalocyanine pigment represented by the general formula CI) as possible in order to obtain sufficient absorbance, and is thin (819), for example 5 pm or less, in order to shorten the range of the generated charge carriers. Preferably 0.01-
It is desirable to use a thin M calendar with a film thickness of 1 μm.

The charge generation layer can be formed by dispersing the phthalocyanine pigment represented by the general formula (I) in a suitable binder and coating it on a conductive support, or by forming a vapor deposited layer using a vacuum vapor deposition apparatus. can.

As a binder used when forming by coating,
One can choose from a wide variety of insulating resins and organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinylanthracene and polyvinylpyrene.

Preferably polyvinyl butyral, polyarylate (condensation polymer of bisphenol A and phthalic acid, etc.), polycarbonate, polyester, phenoxy resin, polyvinyl acetate, acrylic resin, polyacrylamide, polyamide, polyvinylpyridine, cellulose resin, polyurethane, epoxy resin , casein, polyvinyl alcohol,
Examples include polyvinylpyrrolidone.

The resin contained in the charge generation layer is suitably 80% by weight or less, preferably 40% by weight or less.

The solvent that dissolves these resins varies depending on the type of resin, and is preferably selected from types that do not dissolve the charge transport layer or the undercoat layer.

Specifically, alcohols such as methanol, ethanol, and impropatol, ketones such as acetone, methyl ethyl ketone, and cyclohexanone, amides such as N,N-dimethylformamide, N,N-dimethylacetamide, and sulfoxides such as dimethyl sulfoxide. kind,
Ethers such as tetrahydrofuran, dioxane, ethylene glycol monomethyl ether, esters such as methyl acetate and ethyl acetate, aliphatic halogenated hydrocarbons such as chloroform, aliylated methylene, dichloroethylene, carbon tetrachloride, trichloroethylene, benzene, toluene, etc. , xylene, ligroin, chlorobenzene,
Aromatic compounds such as dichlorobenzene can be used.

As the coating method, a dip coating method, a spray coach ink method, a spinner coach ink method, a bead coating method, a Meyer bar coating method, a blade coating method, a roller coating method, a curtain coating method, and the like can be adopted.

Drying is preferably done by drying to the touch at room temperature and then heating. Drying by heating is performed at a temperature range of 30 to 200°C for 5 minutes or more.
Testing is carried out for 2 hours in a stationary or ventilated environment.

The charge transport layer is electrically connected to the charge generation layer,
It has the function of receiving and taking charge carriers injected from the charge generation layer in the presence of an electric field and transporting these charge carriers to the surface. At this time, the charge transport layer may be laminated on or under the charge generation layer.

The charge transport layer is formed by dissolving a fluorene compound represented by general formula (II) together with a suitable binder and coating the solution.

Examples of the binder include acrylic resin, polyarylate, polyester, polycarbonate polystyrene,
Acrylonitrile-styrene copolymer, acrylonitrile-butadiene copolymer, polyvinyl butyral,
Examples include insulating resins such as polyvinyl formal, polysulfone, polyacrylamide, polyamide, and chlorinated rubber, and organic photoconductive polymers such as poly-N-vinylcarbazole, polyvinylanthracene, and polyvinylpyrene.

Since the charge transport layer has a limit in its ability to transport charge carriers, it cannot be made thicker than necessary. - The thickness between the shells is 5 to 35 JLm, but the preferred range is 8 to 30 JLm.
It is le m.

When forming the charge transport layer by coating, any suitable coating method as described above can be employed.

An electrophotographic photoreceptor having a laminated structure of a charge generation layer and a charge transport layer is provided on a conductive support.

As the conductive support, the support itself has conductivity, for example, metals and alloys such as aluminum and aluminum alloys can be used, and in addition, aluminum, aluminum alloys, indium oxide, tin oxide, and indium oxide-tin oxide can be used. A conductive support comprising a plastic having a layer formed by coating an alloy or the like by vacuum evaporation, a plastic support having conductive particles (e.g. carbon black, silver particles, etc.) coated on the metal support with a suitable binder; Examples include conductive supports made of plastic or paper impregnated with conductive particles, and plastics coated with conductive polymers.

An undercoat layer having barrier and adhesive functions can also be provided between the conductive support and the photosensitive layer.

The undercoat layer can be formed of casein, polyvinyl alcohol, nitrocellulose, ethylene-acrylic acid copolymer, polyamide (nylon 6, nylon 66, nylon 610, copolymerized nylon, alkoxymethylated nylon, etc.), polyurethane, gelatin aluminum oxide, and the like.

The thickness of the undercoat layer is 0.1 to 5 ILm, preferably 0.5
~3kawa m is appropriate.

The electrophotographic photoreceptor of the present invention can be used not only in copiers but also in laser diode printers to fully utilize its performance, and is also widely used in electrophotographic application fields such as LED printers, liquid crystal printers, and laser engraving. Available.

[Example J Example 1 0.0% on an aluminum plate. An undercoat layer was formed using a vinyl chloride-maleic anhydride-vinyl acetate copolymer of IILm.

Next, 5 g of exemplified pigment P-(11) was added to 95 m of cyclohexanone and a butyral resin (butyralization degree 63 mol%).
, number average molecular weight 20,000) was added to the solution and dispersed for 20 hours using a sand mill.

The film thickness after drying this dispersion liquid on the undercoat layer is 0.41
It was coated with a Mayer bar so as to have Lm, and dried to form a charge generation layer.

Next, 5 g of exemplified fluorene compound T-(1) and 5 g of bisphenol Z type polycarbonate resin (viscosity average molecular weight 30,000) were dissolved in 70 ml of chlorobenzene, and this was placed on the charge generation layer so that the film thickness after drying was 174 m. A charge transport layer was formed by applying Meyer bar and drying.

The manufactured electrophotographic photoreceptor will be referred to as photoreceptor 1.

Photoreceptor 1 was tested using an electrostatic copying paper tester Model SP-428.
(manufactured by Kawaguchi Electric) using static method to -5,5K
After being corona charged with V and held in a dark place for 1 second, it was exposed to light using a halogen lamp with an illuminance of 2 lux, and the charging characteristics were measured.

As for the charging characteristics, the surface potential (Vo), the potential when dark decayed for 1 second (Vo), and the exposure amount (E115) required to decay roughly to vDt-115 were measured. Show the results.

VO Knee 715V Vo Knee 703 V E115: 0.481 uxasec Furthermore, the photoconductor l is attached to a cylinder of an electrophotographic copying machine equipped with a -5.6 KV corona charger, an exposure optical system, a developer, a transfer charger, a static elimination exposure optical system, and a cleaner. Paste it on,
Image characteristics were investigated.

This copying machine is configured to produce an image on transfer paper as a cylinder is driven.

Image evaluation was performed in three environments: 10% humidity, 5°C air temperature, 50% humidity, 18°C air temperature, 80% humidity, and 35°C air temperature.

Good images faithful to the original were obtained in both environments. No blurring or blurring of the image was observed even after the 10,000th copy, indicating that the photoreceptor 1 exhibited good image characteristics.

770 to 800n, which is the laser oscillation wavelength of photoreceptor 1
It was found that the sensitivity change over m was extremely small, ΔE=0.27.

Examples 2 to 20 Electrophotographic photoreceptors corresponding to Examples 2 to 2o were produced in the same manner as in Example 1 by combining exemplified pigments and fluorene compounds, and designated as photoreceptors 2 to 2o, each having E 11
5 was measured.

Further, the photoreceptors 2 to 20 are connected to a -5.6 KV corona charger.
It was attached to the cylinder of an electrophotographic copying machine equipped with an exposure optical system, a developing device, a transfer charger, a static elimination exposure optical system, and a cleaner. This copying machine is configured to produce an image on transfer paper as a cylinder is driven.

Using this copier, the initial bright area potential (VL) and dark area potential (Vo) were set to 200V and -700V, respectively, and the bright area potential (yLloooo) after 10,000 uses was set.
The variation amounts ΔVL and ΔvD of the dark potential (Vo 10000 ) were measured.

However, ΔVL and ΔvD are ΔVL= [VL10'00] − [VLO]ΔVo, where the initial bright and dark potentials are vLO and y, o, respectively.
It is expressed as = [Vo ""'] - [VD'].

Show the results.

Combination of exemplary pigment and exemplary fluorene compound
-Fluorene 2 2 F-(1) T-(1) 3 3
F-(2) T-(3)4 4 P-(
3) T-(9)5 5 F-(4)
T-(5) 6 6 F-(6) T-(1)
7 7 F-(6) T-r19) 0 1 2 3 4 5 6 7 8 9 0 0 1 2 3 4 5 6 7 8 9 0 P-(7) P-(8) P-(10) P- (11) P-(11) P-(11) P-(13) P-(15) p-(is) P-(19) P-(19) P-(23) P-(24) T- (6) T-(4) T-(22) T-(16) T-(5) T-(11) T-(9) T-(8) T-(2) T-(3) T- (1) T-(21) T-(12) 1 , 20 1 , 42 1 , 45 1 , 27 1 17 7 5 12 3 A 3 2 5 5 7 0.72 -11 -78
1.11 -11 -
39 1.20 -8 -1
210 0.98 -5
-711 0.52 -3
-1012 0.55-10 -1
313 0.64-12 -31
4 0.72-15 -515
1.09 -7 -71
6 1.00 -3 -
817 0.91 ± O-318
0,78-9-5 191,27-8-2 201,33-4-2 Comparative Examples 1 to 6 Instead of the fluorene compound of Example 1, compounds H-(1) and H-(2 ), H-(3) H-(4), H
Electrophotographic photoreceptors were produced in the same manner as in Example 1 except that -(5) and H-(6) were used as charge transport materials, and comparative photoreceptors 1 to 6 were used to measure charging characteristics.

Also, The amount of potential fluctuation was measured in exactly the same manner as in Example 2.

The results will be described later.

- (1) 1 (2) - (4) 1 (5) - (6) 1 1 1.8 -4
2 +352 2 4.2
-38 -203 3
3.8 -40 -304 4
1.7 -25 -805
5 2.4-40 +406
6 2.2 -20
+50 Comparative Examples 7 to 16 Charge transport materials H-(1), H-(2), H-(3), H
The compounds of -(4), H-(5) and H-(6) and the charge generating substances used in Examples 1.6.10.11.13 and 18 were combined as shown below, and the others were the same as in Examples. Electrophotographic photoreceptors were produced in the same manner and designated as Comparative Photoreceptors 7 to 16.

The charging characteristics and potential fluctuation amount of this comparative photoreceptor were measured. Show the results.

Wei7 7 F-(11) H-(1)8
8 F-(6) H-(6)9 9
F-(6) H-(3)10 10 F
-(7) H-(5) 11 11 F
-(10) H-(4)12 12 P
-(11) H-(3) 13 13 F
-(11) H-(2) 14 14 F
T-(15) H-(1)15 15
F-(19) H-(6)16 16
F-(23) H-(2)7 3.7
-60 -508 2.4 -40
+209 4.2 -70
-8010 3.2 -50 +1
511 2.8 -37 -8212
3.6 -70 +3013
2.9 -60 -7014
4.9 -51 -4515 3.
1 -82 -9016 4.2
-91 +20 From the above results, it can be seen that the electrophotographic photoreceptor of the present invention is excellent in sensitivity and repeated potential characteristics.

Examples 21 to 25 Regarding the photoreceptors 7, 10, 11, 14 and 17,
After exposing these to 120 ppm ozone for 30 minutes and further exposing them to 80 ppm HNO3 gas for 1 hour,
Charging characteristics were measured in exactly the same manner as in Example 1. Show the results.

21 7 705 22 10 702 23 11 672 24 14 703 25 17 697 697 0.73 B89 0.92 863 0.49 694 1.15 691 1.02 Comparative Examples 17-21 Comparative Photoreceptor 9, 11.12.14 The charging characteristics were measured in exactly the same manner as in Example 21 using Samples and No. 15. Show the results.

17 9 650 610 4.71
8 11 570 510 2.719
12 620 530 4.120
14 630 590 4.621
15 590 540 3.4 From the above results, it can be seen that the electrophotographic photoreceptor of the present invention is extremely stable against oxidizing substances caused by corona charging, such as ozone and nitric acid.

[Effects of the Invention j] By combining a specific charge-generating substance and a specific charge-transporting substance, the electrophotographic photoreceptor of the present invention has (1) high sensitivity and flat spectral characteristics in the oscillation wavelength range of a laser diode; 1) Exhibits stable image characteristics in the electrophotographic process, and 2) Excellent potential stability.

Claims (1)

[Claims] 1. In an electrophotographic photoreceptor comprising at least two layers, a charge generation layer and a charge transport layer, provided on a conductive support, the charge generation layer is a charge generation substance represented by the following general formula (I). consisting of a layer containing at least one phthalocyanine pigment,
An electrophotographic photoreceptor characterized in that the charge transport layer comprises a layer containing at least one fluorene compound represented by the following general formula (II) as a charge transport substance. General formula▲There are mathematical formulas, chemical formulas, tables, etc.▼(I) In the formula, R_1 is a hydrogen atom, an alkyl group, a halogen atom,
represents a cyano group or a nitro group, m is an integer of 1, 2, 3 or 4, M represents a metal atom except for an alkali metal, and for Y and n, M is not divalent; is trivalent, Y represents a halogen atom, an alkyl group or an alkoxy group, n is an integer of 1,
When M is tetravalent, Y represents an oxygen atom, a halogen atom, an alkyl group, or an alkoxy group; in the case of an oxygen atom, n is an integer of 1; in the case of other than an oxygen atom, n is an integer of 2; General formula▲There are mathematical formulas, chemical formulas, tables, etc.▼(II) In the formula, R_2 and R_3 represent an alkyl group, and R_
4 represents a hydrogen atom, an alkyl group, an alkoxy group, or a halogen atom, and R_5 and R_6 represent a hydrogen atom, an alkyl group, an aralkyl group, or an aryl group. 2. The charge transport layer has the following general formula (III
2. The electrophotographic photoreceptor according to claim 1, comprising a layer containing at least one fluorene compound represented by the following formula. General formula ▲ Numerical formula, chemical formula, table, etc. ▼ (III) In the formula, R_7 and R_8 represent a methyl group or an ethyl group.