JPS59116754A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To enhance sensitivity and durability by an electrophotographic sensitive body by forming two or three photoconductive layers different in the crystal from of phthalocyanine and/or the metal from each other. CONSTITUTION:Photoconductive layers made by dispersing phthalocyanine as a photoconductor into a binder resin to obtain an electrophotographic sensitive body. Two or three photoconductive layers are formed and each are made different from each other in the crystal form of phthalocyanine and/or the combined metal. The multilayer photosensitive body using such a compd. can be changed optionally in the light decay characteristics as compared with a single layer photosensitive body using phthalocyanine alone as a photoconductor. Such an electrophotographic sensitive body is improved sensitivity and responsiveness to light, and enhanced in stability during repeated uses, as compared with a single layer type using a photoconductor.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides an electrophotographic photoreceptor in which a photoconductor layer containing phthalocyanine as a photoconductor element dispersed in a binder resin is formed on a conductive support. The present invention relates to an electrophotographic photoreceptor having two or more body layers.

General electrophotography (xerography) is one type of xerography. A photoreceptor in which a thin film of a conductor element such as selenium or cadmium sulfide is formed on a metal drum is charged in a dark place, and a light image is irradiated (exposure). After forming an electrostatic latent image, a visible image is created with toner (development), and this is transferred and fixed onto paper, etc. A method in which a photoconductive layer is provided on paper, such as in the Arike Electron or Kuss method. , charging, exposure, and development 2 on this photoreceptor.
There are methods of obtaining a permanent visible image on the photoconductive layer by fixing and fusing.

Photoconductor elements currently widely used as photoconductor elements for electrophotographic photoreceptors include anatomical selenium, cadmium sulfide, zinc oxide, and polyvinylcarbazole. Amorphous selenium has good properties as a photoconductor element, but it is difficult to manufacture because it must be manufactured by vapor deposition, and the vaporized M film is not flexible and is highly toxic, so be careful when handling it. The drawback is that it requires a lot of time and is expensive.

Cadmium sulfide and zinc oxide are used in the form of a photoconductive layer dispersed in binder resin, but practical sensitivity cannot be obtained unless the resin/photoconductor element weight ratio is less than 02 to 03. Therefore, it has disadvantages in mechanical properties such as flexibility, smoothness, hardness, tensile strength, and abrasion resistance. Therefore, the same size cannot withstand repeated use. On the other hand, although polyvinylcarbazole has advantages such as charge retention, transparency, and self-forming polymeric photosensitive phase, its photosensitivity is significantly inferior to that of inorganic photosensitive materials, so it is not suitable for improving sensitivity. C1. Unless a new sensitizer is developed, it will not be put to practical use.

On the other hand, indigo, thioindigo, perylene pigments, etc.
Although photoconductivity has been known for a long time, it lacks sufficient sensitivity and has problems in terms of practicality.

In addition, electrophotographic photoreceptors using phthalocyanine on a photoconductor element are also known, and electrophotographic photoreceptors using an inorganic photoconductor element (e.g., flexibility, workability, etc.) are known. Although it is excellent in terms of non-toxicity, it does not necessarily have sufficient sensitivity, has somewhat poor stability after repeated use, and has problems in terms of practicality.

Conventionally, two methods have been known for sensitizing electrophotographic photoreceptors using phthalocyanine or the like as a photoconductor element: chemical sensitization and optical sensitization. Polycyclic or heterocyclic nitro compounds such as 9-fluorenone, quinones such as anthraquinone, aromatic amino compounds such as tetramethyl-P-phenylene-diamine, and dilyl compounds such as tetracyanoethylene are known. It is being In addition, as an optical sensitizer,
Xanthene dyes and quinoline dyes are known, and each is known to have a sensitizing effect. however,
When put to practical use, the sensitivity was still somewhat insufficient, and further improvements in sensitivity and stability through repeated use were desired.

An object of the present invention is to provide an electrophotographic photoreceptor having excellent sensitivity. Furthermore, the present invention provides an electrophotographic photoreceptor that has excellent electrophotographic properties such as stability of sensitivity after repeated use.

That is, in an electrophotographic photoreceptor in which a conductive support is provided with a photoconductor in which phthalocyanine is used as a photoconductor element and is dispersed in a binder resin, two or three or more photoconductor layers are provided. and an electrophotographic photoreceptor having different crystal forms and/or metals of phthalocyanine between the layers.

Specific materials for the photoconductor element according to the present invention are shown below.

The phthalocyanine may be metal-free, copper, metal phthalonanine such as konokuruto, 2, kel, etc., but
It is sufficient that it has at least photoconductivity. Also,
Various crystal forms of phthalocyanine are known, including α,
Various forms such as β, γ, ε, and δ can be used, but any crystal form of phthalonanine having photoconductivity may be used. Preferably, the diffraction angle 2θ±02 degrees shown in JP-A-51-109841 is 70 degrees, 7.7 degrees, and 9 degrees.
．． Copper phthalonanine having an X-ray diffraction diagram showing three strong lines at 2 degrees or ε-type copper phthalocyanine disclosed in Japanese Patent Application Laid-Open No. 50-38543 is used.

As the photoconductor element according to the present invention, various types of phthalocyanine elements can be used, such as those described in 2.2, which are dispersed in a binder resin and exhibit photoconductivity. The photoconductor element can be used with a low content, has excellent flexibility and processability, and has a sensitivity comparable to that of an inorganic photoconductor element GC, making it a practically useful electrophotographic photoreceptor. is obtained.

Furthermore, according to the present invention, a multilayer photoconductor using phthalocyanines with different crystal forms or phthalocyanines with different metals in the photoconductor element is different from a single-layer photoconductor (in which the photoconductor element is simply a phthalocyanine). The attenuation characteristics can be changed arbitrarily. Figure 1 shows the measured cheater showing the electrophotographic characteristics. This data is the result of measuring the photoreceptor with an electrostatic recording tester (SP-428 manufactured by Kawaguchi Electric). Yes.The measurement method is to set the photoreceptor to corona voltage +
After charging at 5.5 KV, 10 Lux light was irradiated for 5 seconds using a tungsten lamp. The surface potential at that time is shown. The attenuation (light attenuation) characteristics of the surface potential under light irradiation are
It varies depending on the photoconductor element used. For example, Figure 1 shows a sign with significant attenuation, and Figure 2 shows a sign with extremely gradual attenuation.
We have shown the case where this happens. This attenuation characteristic is an important characteristic that influences the gradation characteristics of image quality when used in electrophotographic photoreceptors. In the case of a single-layer phthalonanine photoreceptor, its attenuation characteristics are determined by the photoconductive element used, but it is not possible to obtain sufficiently satisfactory characteristics for practical use. In other words, if attenuation occurs as shown in Figure 1 (), the sensitivity is good, but the attenuation is significant, resulting in insufficient gradation reproducibility of the image quality, or as shown in Figure 2. If the attenuation is slow, the sensitivity may be insufficient.In contrast, in the photoreceptor of the present invention, which has multiple layers of phthalocyanine with different crystal shapes and metals, the light attenuation characteristics are as shown in Figures 3 and 4, for example. The cases shown in FIGS. 3 and 4 have good sensitivity and gradation reproducibility, and are therefore advantageous in practical use as photoreceptors.

In addition, VO in Figs. 1 to 4 is the surface potential at the initial stage,
The arrow indicates that irradiation was performed with a tungsten lamp.

As a photoconductor element in a multilayer photoconductor layer, a phthalonanine photoconductor element having a different crystal form or a phthalocyanine photoconductor element having a different metal is used in each layer. Of course, a multilayer photoconductor layer having different crystal shapes and metal atoms may also be used. Alternatively, the blending ratio or types of phthalocyanines in one layer may be changed.

The method for dispersing -\ in the binder resin of the photoconductor element is as follows:
A photoconductive coating liquid is prepared by uniformly dispersing the binder resin and a solvent using a mixed wire dispersion machine such as a ball mill sand mill, roll mill, attritor, vibration mill, or ultrasonic dispersion machine. Further, additives such as ordinary dye increasing/subtracting agents, chemical increasing/subtracting agents, etc. can also be blended into the photoconductive coating liquid. This photoconductive coating liquid is applied to an aluminum plate commonly used for electrophotographic photoreceptors.
It is applied to a conductive support such as paper, plastic, or film that has been subjected to conductivity treatment by vapor deposition, lamination, etc., to form a photoconductor layer. As for the application method, if necessary, add a solvent to the photoconductive coating liquid to adjust the viscosity, and use an air doctor coater, blade coater, spray coater, I-noper coater, spray coater, hot coater, or spray coater. A film is formed by a coating method such as the above, and after coating, it is dried using a suitable drying device, and this operation is performed sequentially to form a multilayer photoconductor layer. Alternatively, a layer normally formed as an electrophotographic material may be provided on the conductive support or on the outermost photoconductor layer.

The binder resin according to the present invention includes melamine resin,
Volume resistivity of epoxy resin, silicon cumulative 1 fat, polyurethane resin, acrylic resin, vinyl chloride-vinyl acetate copolymer resin, polycarbonate resin, cellulose derivative, etc. is 1
A resin having an insulating property of 07Ω or more is used, but it is preferable that the binder resin in the photoconductor layers other than the photoconductor layer furthest from the conductive support is a curable resin.

The electrophotographic photoreceptor of the present invention has higher sensitivity and improved response to light than the conventional one-layer photoconductor using a photoconductor element, and has excellent stability during repeated use. It has certain characteristics.

Next, the present invention will be explained based on examples. However, the present invention is not limited to these examples.

Example 1 Photoconductive paint (1) ε, L [7 Talo 7 Anine (Onoru ER manufactured by Toyo Ink Manufacturing Co., Ltd.) 8.0% by weight Tesmofen + SOO (Polyester polyol solid content manufactured by Nippon Polyurethane Co., Ltd. 75% by weight) 100
72. Of
f Sumidur N-75 (manufactured by Sumitomo Bayer, hexamethylene diisocyanate solid content 75 weight-1iiz)
xo, 6z amount s or more of the composition in a vibration mill 1
The photoconductive paint (1) obtained by kneading for a time is applied to a hard aluminum plate with a thickness of about 80 μm to a coating thickness of 25 to 30 μm (C) to form a photoconductive layer, and heated uniformly to 150 μm. It was dried in a heated oven for 30 minutes.

Photoconductive paint (■) α-type copper phthalocyanine 97 weight ratio Tesmofen + 800 9.7N Seronlube acetate
7o9 Sumidur N-759.7. .

The above composition is dispersed in the same manner as the photoconductive coating liquid (1), and the obtained photoconductive coating liquid (II) is used as the photoconductive coating liquid (1).
The conductor layer was coated with a coating thickness of 5 to 10 μm and dried in an oven uniformly heated to 150° C. for 30 minutes. This electrophotographic photoreceptor is called Sample A. +5 for the sample AK thus obtained
, 5KV, corona gag 10g1, and a charging speed of 1Qm/min. After stopping the discharge, 5 seconds later, the sample was exposed to 2854°K tungsten light at an illuminance of IQLux. The amount of light irradiation required for the potential immediately before exposure to decrease by 50% at this time was defined as the sensitivity. Sample A measured in this manner had a maximum surface charge potential of 280■ and a sensitivity of 6.5.
The electrophotographic photoreceptor with Lux*Secte had sufficient chargeability and sensitivity, and was highly sensitive, highly practical, and non-polluting. Figure 3 shows the change in surface potential at this time.

Example 2 A photoconductive layer was formed using the photoconductive coating liquid (1) of Example 1 on a 75 μ thick polyester film coated with aluminum to a coating thickness of 25 to 30 μ, and uniformly heated at 150°C. It was dried for 30 minutes in a heated oven.

Photoconductive paint (lII) β-type steel phthanidianine 9.2-tE 3t % Tesmofen ≠ 800 4.0# Selon Lube Acetate 1 = 82.8# Sumigeel N-754, OI The above composition was used as a photoconductive coating liquid Distributed using the same method as (1) [
2. The obtained photoconductive coating liquid aII) was mixed with photoconductive coating liquid (1
) was coated on the photoconductor layer formed in step 1 to give a film thickness of 5 to 10 μm, heated uniformly to 150° C., and heated to +1. Dry in a heated oven for 30 minutes.

Further, the same photoconductive coating liquid (II) as in Example 1 was applied on the photoconductive layer formed from the photoconductive coating liquids (1) and (U).
An electrophotographic photoreceptor was prepared by applying the film to a coating thickness of ~JOμ and drying it for 30 minutes in an oven uniformly heated to 150°C.
It is called. The charge amount and sensitivity were measured in the same manner as in Example 1. The results are shown in Table 1. A product with excellent sensitivity was obtained.

Example 3 Photoconductive coating liquid ■) β-type metal-free phthalocyanine 44.5'f Takera, UA702 (Acrylic polyol solid content 50M mass % manufactured by Narita Pharmaceutical Co., Ltd.) 11.0 Weight ratio Coronate L (Nippon Polyuretano Industries) A photoconductive coating liquid (v) obtained by kneading a composition of tolylene diincyanate (solid content 75ffi:%) 3.2 weight ratio methyl ethyl ketone 41.3 p or more in a ball mill for 488 hours was coated into a layer with a thickness of about 80 μm. 2 on a hard aluminum plate
A photoconductor layer is formed to have a coating thickness of 5 to 30μ,
It was dried for 30 minutes in an oven uniformly heated to 100°C.

ε-type copper phthalocyanine 9.8 Weight section Takera, RiUA7 (J2 32.3 〃Coronate L
9.3.

Methyl ethyl ketone 486 The above composition is dispersed in the same manner as the photoconductive coating liquid (V), and the resulting photoconductive coating liquid (V) is used as a photoconductive layer formed with a photoconductive amount fi, (foundation). It was coated on the body layer to a coating thickness of 5 to 10 μm and dried in four stripes. The electrophotographic photoreceptor thus obtained is called Sample C. The charge amount and sensitivity were measured in the same manner as in Example 1, and the results are shown in Table 1. A product with excellent sensitivity was obtained. Figure 4 shows the change in surface potential at this time.

Example 4 A chemical sensitizer TEL 2.4 was added to the photoconductive coating liquid (1) of Example 1 at a ratio of 500 parts by weight to ε type steel phthalocyanine.
．． 5. Add 7-tetranitro-9-fluorenone,
A photoconductor layer of 5 to 10 μm in thickness (C) was formed on a hard aluminum plate of approximately 80 μm thickness and dried in the same manner as in Example 1. Coating liquid (H
) was applied to a coating thickness of 25 to 30 μm and dried in the same manner as in Example 1 to prepare an electrophotographic photoreceptor. This electrophotographic photoreceptor is called Sample D. The measurement T of the amount of charge and sensitivity was as in Example 1. The results are shown in Table 1. A product with excellent sensitivity was obtained.

Example 5 ε-type copper phthalocyanine and α-type copper 7-talonanine, which are photoconductive elements in the photoconductive coating liquid (1) and (U) composition of Example 1, were replaced with ε-type metal phthalocyanine and α-type metal-free. Photoconductive coating liquids (Vl) and (4) were prepared by changing lt MH composition to phthalocyanine.

A photoconductive coating liquid (Vl) dispersed in the same manner as in Example 1 was used to form a photoconductive layer on a hard aluminum plate with a thickness of about 80 μm to a coating thickness of 25 to 30 μm, and was heated uniformly at 150° C. Dry in a heated oven for 30 minutes. Sara [C
Coat the photoconductive coating liquid on the photoconductor layer prepared at ℃ to a coating thickness of 5 to 10μ,
It was dried under the same conditions. This electrophotographic photoreceptor is called Sample E. The charge amount and sensitivity were measured in the same manner as in Example 1, and the results are shown in Table 1. A product with excellent HLT sensitivity was obtained.

For the t-2ε-type metal-free phthalocyanine, 100 parts by weight of α-type metal-free phthalocyanine and 0.3 parts by weight of a copper phthalocyanine derivative were added to 100 parts by weight of a copper phthalocyanine derivative.
It was obtained by stirring at ℃ for 30 minutes.

Example 6 A photoconductive layer was formed using the photoconductive coating liquid of Example 3 on a hard aluminum plate with a thickness of about 80 μm to a coating thickness of 25 to 30 μm, and the film was heated uniformly to 100° C. It was dried in a heated oven for 30 minutes.

Photoconductive coating liquid ■ ε-type copper phthalocyanine 8.5% by weight Epicor 1
- ≠1007 (epoxy resin solid content 40% by weight H% methyl ethyl ketone solution manufactured by Shell Chemical ■)
53.8 Cellosolve Bucetate by Weight 37.7 〃 Photoconductive coating liquid (IV) obtained by kneading the above f and D acids for 1 hour in a vibrating mill is used as photoconductive coating liquid (IV) The photoconductor layer was coated with a coating thickness of 25 to 30 μm and dried for 30 minutes in an oven uniformly heated to 1.100°C. Sample F of this electrophotographic photoreceptor
It is called. The charge amount and sensitivity were measured in the same manner as in Example 1, and the results are shown in Table 1. A product with excellent sensitivity was obtained.

Example 7 Photoconductive coating liquid (■)
86.9 #Sumijiel N-75
1.5 Disperse the above composition in a ball mill for 24 hours and apply the resulting photoconductive coating liquid ■ onto a hard aluminum plate approximately 80μ thick so that the coating thickness is 25 to 30μ. A layer was formed and dried for 30 minutes in an oven uniformly heated to 150°C.

Photoconductive coating liquid (X) α-type steel phthalocyanine 8.7 Heavy Ja % Dessuphen+800 9.7 s Cellosolve acetate 71.9.

Smithiel N-759,7.

The above composition is dispersed in the same manner as the photoconductive coating liquid (X), and the resulting photoconductive coating liquid (X) is applied to the photoconductive layer formed with the photoconductive coating liquid (5 to IOμ). It was dried under the same conditions as (C coating, photoconductive coating liquid 11X) to obtain a coating thickness.

This electrophotographic photoreceptor total sample G is called. The charge amount and sensitivity were measured in the same manner as in Example 1, and the results are shown in Table 1.

A product with excellent sensitivity was obtained.

Example 8 The photoconductive coating liquids (IX) and (X) of Example 7 were replaced with lead phthalocyanine and β-type copper phthalocyanine for the photoconductive elements to create photoconductive coating liquids (X) and Flashp. . After dispersing in the same manner as in Example 7, a photoconductor layer (C) was formed on a hard aluminum plate having a thickness of about 80 μm to a coating thickness of 25 to 30 μm, and dried in the same manner as in Example 7. Furthermore, the photoconductive coating liquid (6) was applied onto the photoconductor layer formed with the photoconductive coating liquid (Fig. ．． Ta. The electrophotographic photoreceptor thus obtained is called Sample H.

The amount of charge and sensitivity were measured in the same manner as in Example 1, and the results are shown in Table 1. 10 were found to have excellent sensitivity.

Example 9 Photoconductive coating liquid (Xllll) -u Aluminum phthalocyanine 9.5 weight ratio Takera, RiUA702 42.0 〃Coronate L 12.3 〃Methyl ethyl ketone 362 Rose Bengal as a dye sensitizer in a composition of N or more was added and dispersed using an ultrasonic disperser.

The thus obtained photoconductive coating liquid (XI[I) was applied to a 100μ thick polyester film coated with aluminum by vapor deposition.
A photoconductor layer was formed on the film to a coating thickness of 25 to 30μ, and then heated in an oven uniformly heated to 100°C for 3
Let dry for 0 minutes.

Photoconductive coating liquid (XIV) β-type metal-free phthalocyanine 8.1! -ft% Takera, RIUA702 51.9 〃Coronet)L
L4.9 L'methyl ethyl ketone 25. An appropriate amount of Rhodamine B as a dye sensitizer was added to the composition above IN and dispersed using an ultrasonic disperser.

The thus obtained photoconductive coating liquid (XIV) was applied onto the photoconductor layer formed with the photoconductive coating liquid (XIII) for 25 to 30 minutes.
Coating film thickness of μ (/ to form a photoconductor layer,
It was dried for 30 minutes in an oven uniformly heated to 80°C. The thus obtained electrophotographic photoreceptor sample is referred to as ①. The measurement of the amount of MN and the sensitivity was carried out in the same manner as in Example 1, except that the polarity of the corona charge was changed to ←), and the results are shown in Table 1. Also, one with excellent sensitivity can be obtained.

Comparative Example 1.2 A photoconductive layer was formed using photoconductive coating liquids (1) and (n) on a hard aluminum plate having a thickness of approximately 80 μm to a coating thickness of 25 to 30 μm, and the coating was heated at 150°C. It was dried for 30 minutes in an evenly heated oven. This electrophotographic photoreceptor is referred to as Sample J. The amount of charge and sensitivity were measured in the same manner as in Example 1, and the results are shown in Table II.
:P, but compared to the electrophotographic photoreceptors shown in Examples 1 to 8, Sample J and Sample had lower sensitivity and were inferior.

Table 1

[Brief explanation of drawings]

1 to 4 show changes in the surface potential of the photoreceptor during charging and exposure. patent applicant

Claims (1)

[Claims] ■ In an electrophotographic photoreceptor in which a photoconductor layer in which phthalocyanine as a photoconductor element is dispersed in a binder resin is provided on a conductive support, two or more photoconductor layers are provided. 1. An electrophotographic photoreceptor characterized in that the crystal forms and/or metals of phthalocyanine between the layers are different.