JPH03174542A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain an electrophotographic sensitive body having sufficiently high sensitivity and flatness of spectral sensitivity even in a long wavelength region by forming a specified electric charge generating layer and a specified electric charge transferring layer on an electrically conductive substrate. CONSTITUTION:An electric charge generating layer contg. a phthalocyanine pigment represented by formula I as an electric charge generating material and an electric charge transferring layer contg. a biphenyl compd. represented by formula II as an electric charge transferring material are formed on an electrically conductive substrate. In the formula I, R1 is H, etc., m is an integer of 1-4, M is a metal atom other than alkali metal atoms, when M is trivalent, Y is halogen, etc., and n is 1, and when M is tetravalent, Y is O, etc., and n is 1 in the case where Y is O or n is 2 in the case where Y is not O. In the formula II, each of R2 and R3 is alkyl, etc., and R4 is alkyl, alkoxy, etc. High sensitivity and flat spectral characteristics are obtd. in a long wavelength region.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to an electrophotographic photoreceptor, and more particularly to a plant-type 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 inorganic electrophotographic photoreceptors are not necessarily satisfactory in terms of thermal stability, moisture resistance, and durability, and in particular, 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 attracted attention in recent years.

Such organic photoreceptors include photoconductive polymers typified by poly-N-vinylcarbazole and charge transfer complexes formed from this and Lewis acids such as 2.4.7-1 linitro-9-fluorenone. An electrophotographic photoreceptor having a photosensitive layer containing as a main component has 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, the number of functions has increased in order to set the spectral sensitivity range that matches the emission wavelength of the light source used. # type is suitable.

As charge generating substances, various azo pigments, phthalocyanine pigments, polycyclic quinone pigments, cyanine dyes, squaric acid dyes, biryllium salt dyes, etc. are known.

Among them, many structures have been proposed for azo pigments because of their strong light resistance, large charge generation ability, and ease of material synthesis.

For example, as a disazo pigment similar to the charge generating substance in the present invention, Japanese Patent Application Laid-Open No. 56-116040, Japanese Patent Application Laid-open No. 57
-182747, JP 58-49952, JP 58-115447, JP 59-72
448, JP 59-155848, JP 58-115445, JP 58-11544
6, Japanese Patent Application Laid-Open No. 59-7365, etc., and are well known.

The azo pigment used here as a charge generating substance is required to be (D stable against heat and light, (i)
i) For those that exhibit charge generation ability in a dispersed state, dispersion is easy and the dispersion liquid has little change over time; (
iii) the charge generation ability does not change with temperature; (I
v) No change in characteristics during repeated use, C
V) It has an effective spectral sensitivity range for the light source used, and (vi) The charge transport material is not limited.

In practical terms, it is important to satisfy these requirements at a high level on average.

Although some of the above-mentioned known pigments satisfy some of the above requirements, none satisfy all of them to a high level.

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

These compounds are required to (i) be stable against light and heat; (ii) be stable against ozone, NOx, nitric acid, etc. generated by corona discharge;
(iii) It exhibits high charge transport ability, and (Iv) It has high compatibility with organic solvents and binders.

Examples of combinations of the above-mentioned known azo pigments and charge transport substances include, for example, JP-A-58-18636 and JP-A-Sho 5.
7-204551, JP 59-44050, JP 59-44051, JP 59-15
Examples include descriptions in JP-A No. 7644, JP-A-60-24549, JP-A-60-24550, JP-A-60-24551, and JP-A-60-24552.

Although electrophotographic photoreceptors made with these combinations have little potential fluctuation during repeated use, many of them have serious drawbacks in terms of image characteristics, such as image deterioration due to changes in the usage environment. This has become a problem.

[Problems to be Solved by the Invention] An object of the present invention is to provide an electrophotographic photoreceptor having a charge generation layer and a charge transport layer with sufficient high sensitivity and spectral sensitivity even in a long wavelength range such as the laser diode oscillation wavelength range. To provide an electrophotographic photoreceptor having a flatness of 1,000,000 yen, and an annular electrophotographic body whose potential is maintained stably during repeated use, and which exhibits stable potential characteristics and image characteristics regardless of the usage environment (temperature, humidity). Another object of the present invention is to provide an electrophotographic photoreceptor using an azo pigment in which the azo pigment can be easily dispersed and the dispersion liquid has little change over time.

[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: It consists of a layer containing at least one type of phthalocyanine pigment represented by (1), and the charge transport layer has the following general formula (2) as a charge 1 transport material.
) is comprised of an electrophotographic photoreceptor characterized by comprising a layer containing at least one type of hypohenyl compound.

(In the formula, R1 represents a hydrogen atom or a halogen atom,
m is an integer of 1.2, 3 or 4, M represents a metal atom excluding alkali metals, and for Y and n,
There is no case where M 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 when M is tetravalent, Y represents an oxygen atom, a halogen The atom represents an alkyl group or an alkoxy group, where n is an integer of 1 in the case of an oxygen atom and an integer of 2 in the case of other than an oxygen atom. (In the formula, R2 and R3 represent an alkyl group or an alkoxy group, and R4 represents an alkyl group, an alkoxy group, an aralkyl group, a hydroxyl group, or a halogen atom.) More specifically, as the above group, the alkyl group is a methyl group. , ethyl, propyl, butyl, etc. The alkoxy group is a group such as methoxy, ethoxy, propoxy, etc., the aralkyl group is a group such as benzyl, phenethyl, etc., and the halogen atom is a chlorine atom, dibromine atom, fluorine atom, or iodine atom.

Metal atoms M include Ti, V, Cr, Fe, Cu, and Z.
n, Ga, AM, Pb, Ge, Sn, 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.

Basic type exemplified pigments P-(1) R1; H P-(2) R1: C-view P-(3) R1: Br P-(4) R1: H P-(5) R1: H P-(6) R1:HP-(7) R1:C a1 m:2 m:4 m:1 m:1 m:1 m:4 M:Cu M:Cu M:Cu M:Fe M:Snica M:A Y 2 - Y 2 - Y 2 - Y 2 - Y: C or Y 2 - Y:C1 n:2 n:1 P-(8) R1:H a1 M:A Y:CR n:1 P-(9 ) R1:H P-(10) RL+F P-(11) m:1 m: 4 M: In M:Zn Y 20 Y: - n:1 R1:H a1 M: Zn Y 2-P-( 12) R1:H a1 M:Ti Y:0 n:1 P-(13) R1:)! a1 M: Tt Y: -0CH3 n:2 P-(14) R1:H m:1 M:v Y20n:1 Charge transport substance exemplified compound T-(1) - (2) - (3) - (4) - (5) - (6) - (7) - (8) - (9) - (10) T-(11) T-(12) T-(13) T-(14) In the present invention The combination of the phthalocyanine pigment represented by general formula (1) and the biphenyl compound represented by general formula (2) is
This is probably due to the good compatibility of ionization potentials and the good steric formation of the phthalocyanine pigment and biphenyl compound at the interface between the charge generation layer and the charge transport layer. Because injection into the transport layer is done quickly and smoothly,
It is considered to have extremely high sensitivity and excellent potential stability during durability.

Next, the electrophotographic photoreceptor of the present invention will be explained in more detail.

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

The charge generation layer can be formed by dispersing the phthalocyanine pigment represented by the general formula (1) in a suitable binder and coating it on a conductive support, or a yXM film can be formed using a vacuum evaporation device. can.

As a binder used when forming by coating,
You can also choose from a wide range of insulating resins.

It can be selected from 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 isopropanol, 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, ethyl acetate, aliphatic halogenated hydrocarbons such as chloroform, methylene chloride, dichloroethylene, carbon tetrachloride, trichloroethylene, or benzene,
Aromatic compounds such as toluene, xylene, ligroin, chlorobenzene, and dichlorobenzene can be used.

As a coating method, a dip coating method, a spray coating method, a spinner coating 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 the biphenyl compound represented by the general formula (2) together with a suitable binder and applying 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 to its ability to transport charge carriers, it cannot be made thicker than necessary.
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, metals and alloys such as aluminum, aluminum alloy, etc., which are conductive themselves, can be used, and in addition, aluminum, aluminum alloy, indium oxide, tin oxide, indium oxide-tin oxide, etc. can be used. Plastics having a layer formed by coating an alloy etc. by vacuum evaporation force, JT in which conductive particles (e.g. carbon black, silver particles, etc.) are coated on the metal support with a suitable binder.
Examples include L-type supports, conductive supports obtained by impregnating conductive particles into plastic or paper, and plastics containing conductive polymers.

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

The subbing layer can be formed from casein, polyvinyl alcohol nitrocellulose, ethylene-acrylic acid copolymer, polyamide (nylon 6, nylon 66°, nylon 610, copolymerized nylon, flukoxymethylated nylon, etc.), polyurethane, gelatin, aluminum oxide, etc. .

The film thickness of the underlayer dust is 0.1 to 5 gm, preferably 0.5 to 5 gm.
3 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. can.

[Examples] Example 1 An undercoat layer using a 0.1 pm vinyl chloride-maleic anhydride-vinyl acetate copolymer was formed on an aluminum plate.

Next, 5 g of Exemplified Pigment P-(12) was added to a solution prepared by dissolving 2 g of butyral resin (degree of butyralization: 63 mol %, number average molecular weight: 20,000) in 95 mJL of cyclohexanone, and dispersed in a sand mill for 20 hours.

The film thickness after drying this dispersion liquid on the undercoat layer is 0.4 g.
A charge generating layer was formed by applying Meyer bar and drying.

Next, 5 g of 1 exemplified biphenyl compound T-(1) and bisphenol Z type polycarbonate (viscosity average molecular weight 30,000)
5 g was dissolved in 70 ml of chlorobenzene, and this was coated on the charge generation layer with a Mayer bar so that the film thickness after drying was 17 gm, and dried to form a charge transport layer.

The produced electrophotographic photoreceptor is referred to as photoreceptor 1.

Photoreceptor 1 was tested using an electrostatic copying paper tester Model SP-428.
-5,5K using static method (manufactured by Kawaguchi Denkitai)
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 (VQ) and the exposure i (E 115) required to attenuate the potential (Vo) to 115 when dark decayed for 1 second were measured.

Show the results.

V, knee 715V vo knee 700V E115: 0.36 text uX”sec and photoreceptor l
was attached to the cylinder of an electrophotographic copying machine equipped with a -5.6 KV corona charger exposure optical system, a developer, a transfer charger, a static elimination exposure optical system, and a cleaner, and the characteristics of one image were examined.

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

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

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

770-800n, which is the laser oscillation wavelength range of the photoreceptor l
It was found that the sensitivity change over m was extremely small, ΔE=0.22.

Examples 2 to 12 Electrophotographic photoreceptors corresponding to Examples 2 to 12 were produced in the same manner as in Example 1 by combining exemplified pigments and exemplified biphenyl compounds, and the exposure amount E115 was measured for each of photoreceptors 2 to 12. .

Further, the photoreceptors 2 to 12 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 (VD) were set to -200v and -700v, respectively, and the bright area potential after 10,000 uses was 10,000.
10000 (VL ) and dark potential (Vo
) fluctuation amounts ΔVL and ΔVD were measured.

However, ΔvL and ΔVo are ΔVL = [(VL)] − [(VL 0)], where the initial bright and dark potentials are vL and VD, respectively.
0000 ΔVD= [(Vb 10000)] −[(Vo 0
)] to represent.

Show the results.

Combination composition of exemplary pigment and exemplary fluorene compound
-Fluorene 2 2P-(1)T~(1) 3 3 P-(1)T-(14)4
4 P-(5) T-(3)5 5
F-(7) T-(13)6 6 P-(
8) T-(8)7 7 F-(11)
T~(9)8 8 F-(12) T-(1
3)9 9 F-(12) T-(5)10
to P-(12) T-(7)11
11 F-(13) T-(2) 12 12
F-(14) T-(11)2 1.20
-15 +153 1.32-15
+104 1.50 -20
+55 0.98 -10
06 0.76 -25
+57 1.38-15
+158 0.38 -15
+59 0.43 -10
010 0.51 -20
+511 0.92 -15
+1512 0.87-20
+10 Comparative Examples 1 to 6 In place of the biphenyl compound of Example 1, compounds of the following structural formula H-(1), H-(2), H-(3) H-(4), H
-(5) and H-(6) were each used as a charge transport substance, and an electrophotographic photoreceptor was produced in the same manner as in the Example except that the weight of the comparative photoreceptor was ~6, and the charging characteristics were measured.

Further, the amount of potential fluctuation was measured in exactly the same manner as in Example 2. The results will be described later.

H-(1) H-(2) - (3) - (4) - (5) - (6) 7 1 2 1 8 6 6 3.02
I1. ΔVDV ΔVLV1
1 -70 +4
02 2 -120
+703 3 -150
+1204 4 -
50 +555 5
-75 +606 6
-65 +30 Comparative Example 7
~12 The above charge transport substances H-(1), H-(2), H-(3
), H-(4), H-(5) and H-(6) and the charge generating substances used in Examples 2.3, 5.8.10 and 12 were combined as follows, and others. Comparative photoreceptors 7 to 12 were manufactured in the same manner as in the examples, and their charging characteristics and potential fluctuations were measured. Show the results.

7 F-(1) H-(3) 8 F-(1) H-(6) 9 F-(7) H-(5) 10 10 F-(12) H-(
1) 11 11 F-(12) H
-(2) 12 12 F-(14)
H-(4)7 4.31 -150 +75
8 3.67 -70 +3
09 1.89 -55 +
3510 1.87 -65
+7011 1.55-110 +5512
From the results of 2.71 -90 +30 or more, it can be seen that the electrophotographic photoreceptor of the present invention is excellent in sensitivity and repeatability.

Examples 13 to 17 Photoreceptors 2.3.5.8 and 10, which are electrophotographic photoreceptors of the present invention, were each exposed to 120 ppm ozone for 30 minutes and further exposed to 80 ppm HNO3 gas for 1 hour. 2. The charging characteristics were measured in the same manner as in Example 1. The results are shown below.

13 2 705 690 1.3
014 3 700 670 1.
3515 5 670 665
0.9516 8 690 67
0 0.3817 10 700 6
95 0.57 Comparative Examples 13-17 Example I Using Comparative Photoreceptors 7.8.9, 1O and 11
The charging characteristics were measured in the same manner as in 3.

Show the results.

13 7 670 520 6.40
14 8 700 480 4.21
15 9 650 550 3.
2216 10 570 500 2.
4017 11 675 500 5
．． 03 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] By combining a specific charge-generating substance and a specific charge-transporting substance, the electrophotographic photoreceptor of the present invention has ■high sensitivity and flat spectral characteristics in the oscillation wavelength range of a laser diode; It exhibits stable image characteristics in the electrophotographic process, and has the remarkable effect of (1) 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 (1). An electrophotographic photoreceptor comprising a layer containing at least one phthalocyanine pigment, the charge transport layer comprising a layer containing at least one biphenyl compound represented by the following general formula (2) as a charge transport substance. . General formula▲There are mathematical formulas, chemical formulas, tables, etc.▼(1) (In the formula, R_1 represents a hydrogen atom or a halogen atom, m is an integer of 1, 2, 3, or 4, and M is an integer excluding alkali metals. represents a metal atom, and regarding Y and n, when M is divalent, Y represents a halogen atom, an alkyl group, or an alkoxy group;
is an integer of 1, and when M 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 the case of other than an oxygen atom, n is an integer of 2. ) General formula▲There are mathematical formulas, chemical formulas, tables, etc.▼(2) (In the formula, R_2 and R_3 represent an alkyl group or an alkoxy group, and R_4 represents an alkyl group, an alkoxy group,
Represents an aralkyl group, a hydroxyl group, or a halogen atom. ) 2. The charge transport layer has the following general formula (3) as a charge transport material:
The electrophotographic photoreceptor according to claim 1, comprising a layer containing at least one biphenyl compound represented by: General formula▲There are mathematical formulas, chemical formulas, tables, etc.▼(3) (In the formula, R_5, R_6 and R_7 represent an alkyl group or an alkoxy group.) 3. Claim 1, where the charge generation layer is a charge generation substance In the phthalocyanine pigment represented by the general formula (1),
In the formula, M is a copper atom, or M is a titanium atom, Y
The electrophotographic photoreceptor according to claim 1, wherein is an oxygen atom.