JPH01142659A - Electrophotographic sensitive body - Google Patents

Abstract

PURPOSE:To obtain an electrophotographic sensitive body having chargeability for both positive and negative charge, and improved chargeability and repeatability by incorporating a specified amt. of alpha-type titanyl phthalocyanine compsn. to a binder resin. CONSTITUTION:60-90wt.% alpha-type titanyl phthalocyanine, and 10-40wt.% metal-free phthalocyanine are contained in an alpha-type titanyl phthalocyanine compsn. to be used as a charge generating material. A photosensitive layer is constituted by dispersing the alpha-type titanyl phthalocyanine compsn. and a charge transfer material in a binder resin. In this photosensitive layer, 0.05-5pts. wt. alpha-type titanyl phthalocyanine compsn. is contained in 100pts.wt. binder resin. Thus, an electrophotographic sensitive body having composite dispersion type chargeability for both positive and negative charge, having also high electrifiability of the photosensitive body and high repeatability is obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to an electrophotographic photoreceptor in which the photoreceptor layer is a composite dispersion type and can be charged both positively and negatively.

(Prior art) Electrophotographic photoreceptors that use inorganic photoconductors such as selenium, cadmium sulfide, and zinc oxide as photosensitive components are well known.However, these have poor sensitivity, thermal stability, moisture resistance, It is not always satisfactory in terms of photoreceptor properties such as durability, manufacturing, or toxicity.For example, selenium, which is most commonly used as an electrophotographic photoreceptor, easily crystallizes at about 40°C; This deteriorates the properties of the photoreceptor, making it difficult to control the temperature during manufacturing, and also causes crystallization due to heat and fingerprints when handling the photoreceptor, deteriorating its performance as a photoreceptor. Cadmium sulfide has excellent moisture resistance and durability, and
Even zinc oxide has problems with durability, etc.

In recent years, organic photoreceptors have been used as photoreceptors for electrophotography because they have good processability and are advantageous in terms of manufacturing cost, and also have a large degree of freedom in terms of functional design.

In addition, in the functional design of electrophotographic photoreceptors using the above-mentioned organic photoreceptors, by separating each function into a charge-generating material that generates charges upon light irradiation and a charge-transporting material that transfers the generated charges, Materials can be selected from a wide range, and attempts have been made to increase the surface potential, increase charge retention, and increase photosensitivity by creating a laminated structure of each functional material. There is.

This functionally separated laminated photoreceptor has a structure in which a charge generation layer is provided on a conductive substrate, and a charge transport layer is further provided on top of the charge generation layer, due to the durability of the surface and the fact that many of the charge transport materials are positive charge transport types. It is common to take a negative charge and remove it.

<Problems to be Solved by the Invention> However, in such a negatively charging window light body, ozone is generated in the atmosphere during charging by a corona discharger, causing deterioration of the photoreceptor and contamination of the copying environment, and also causing problems in the development process. Positively charged organic photoreceptors are attracting attention because of problems such as the need for positive polarity toner, which is sometimes difficult to manufacture. Furthermore, for application to color printers and the like, there is a need for a photoreceptor that has electrophotographic properties equivalent to both negatively charged and positively charged so as to be compatible with reversal development.

<Object of the Invention> The present invention has been made in view of the above-mentioned problems, and provides a composite dispersion type electrophotographic photoreceptor that can be charged both positively and negatively.

<Means for Solving the Problems> The present invention provides a composite dispersion type electrophotographic photoreceptor with positive and negative chargeability, which has a photosensitive layer formed by dispersing an α-type titanyl fucrocyanine composition and a charge transport material in a binder resin. As a result, the above objective was achieved.

The α-type titanyl phthalocyanine composition that is the charge-generating material used in the present invention is α-type titanyl phthalocyanine 6.
0-90% by weight and metal-free phthalocyanine 10-4
Since it contains metal-free phthalocyanine as well as α-type titanyl phthalocyanine, when used as a photoconductive material for electrophotographic photoreceptors, it is not only stable but also has excellent charging properties and The photosensitive characteristics, especially the sensitivity, are significantly improved.

The α-type titanyl phthalocyanine composition content is 1 in the binder resin.
If the amount is less than 0.05 parts by weight, the sensitivity of the photoreceptor will be insufficient, and if it is more than 5 parts by weight, the charging ability, repeatability, and abrasion resistance of the photoreceptor will deteriorate.

The above α-type titanyl phthalocyanine composition is produced by, for example, producing titanyl phthalocyanine, turning it into a pigment by an acid paste method in which a sulfuric acid solution containing titanyl phthalocyanine, to which a desired amount of metal-free phthalocyanine has been added as needed, is injected into water. It is produced by wet milling in the presence of a solvent treatment, preferably a chlorinated solvent. Alternatively, the mixture may be prepared by mixing separately produced α-type titanyl phthalocyanine and metal-free phthalocyanine at a predetermined ratio.

The α-type titanyl phthalocyanine composition has Black angles of 6.9°, 9.6°, and 15° in the X-ray diffraction spectrum.
．． 6°, 17.6°, 21.9°, 23.6°, 24.
It shows strong diffraction peaks at 7° and 28.0°, and among the above blank angles, the largest diffraction peak is shown at 6° and 9°.

The electrophotographic photoreceptor of the present invention includes a conductive base material and a photosensitive layer formed on the conductive base material, and the photosensitive layer includes the α-type titanyl phthalocyanine as a charge generating substance. This is a composite dispersion type electrophotographic photoreceptor comprising a composition, a charge transport substance, a binder resin, and other materials as necessary.

The above-mentioned conductive base material may be in the form of a conductive sheet or drum, and may be made of various conductive materials such as aluminum, aluminum alloy, copper,
tin, platinum, gold, silver, vanadium, molybdenum, chromium,
Examples include simple metals such as cadmium, titanium, nickel, palladium, indium, stainless steel copper, and brass, and plastic materials and glass on which layers of the above metals, indium oxide, tin oxide, etc. are formed by means such as vapor deposition.

In addition, charge transport substances include nitro group, nitroso group,
Electron-accepting substances having electron-accepting properties such as cyano groups, such as tetracyanoethylene, fluorenone compounds such as 2,4゜7-dolinitro-9-fluorenone, dinitroanthracene, 2,4゜8-trinidrothioxanthone, etc. Nitrated compound; electron-donating compound, such as N,
Hydrazone compounds such as N-diethylaminobenzaldehyde N, N-diphenylhydrazone, N-methyl-3-carbazolylaldehyde N, and N-diphenylhydrazone, oxadiazole compounds, styryl compounds, pyrazoline compounds, oxazole compounds , nitrogen-containing cyclic compounds such as isoxazole compounds, thiazole compounds, thiadiazole compounds, imidazole compounds, pyrazole compounds, indole compounds, triazole compounds, fused polycyclic compounds such as anthracene, pyrene, phenanthrene, Examples include poly-N-vinylcarbazole, polyvinylpyrene, polyvinylanthracene, and ethylcarbazole-formaldehyde resin.

One or more kinds of the above charge transport materials may be used.

Various binder resins can be used, such as styrene polymers, styrene-butadiene copolymers, styrene-acrylonitrile copolymers, styrene-maleic acid copolymers, acrylic polymers, and styrene-acrylic copolymers. Copolymer, ethylene-vinyl acetate copolymer, polyvinyl chloride, vinyl chloride-vinyl acetate copolymer, polyester, alkyd resin, polyamide, polyurethane, acrylic modified urethane resin, epoxy resin, polycarbonate, polyarylate, polysulfone, diallyl Various polymers are exemplified, such as phthalate resin, silicone resin, ketone resin, polyvinyl butyral resin, polyether resin, and phenol resin. Furthermore, photocurable resins such as epoxy acrylate can also be used. Furthermore, photoconductive polymers as the charge transport material, such as poly-N-
Vinyl carbazole or the like may also be used as a binder resin.

In addition, other materials include conventionally known aggravating agents such as terphenyl, halonaphthoquinones, acenaphthylene, 9-(
Examples of various additives include fluorene compounds such as N,N-diphenylhydrazino)fluorene, deterioration inhibitors such as plasticizers, antioxidants, and ultraviolet absorbers.

The ratio of the α-type titanyl phthalocyanine composition, the charge transport substance, and the binder resin in the photosensitive layer can be appropriately selected depending on the desired characteristics of the photoreceptor. On the other hand, 0.05 to 5 parts by weight of the α-type titanyl phthalocyanine composition and 25 parts by weight of the charge transport material.
~200 parts by weight are used, preferably 50-150 parts by weight.

If the amounts of the α-type titanyl phthalocyanine composition and the charge transport material are less than the above-mentioned amounts, not only the sensitivity of the photoreceptor will not be sufficient, but also the residual potential will increase.

Moreover, when the above range is exceeded, the surface potential of the photoreceptor decreases.

Further, the photosensitive layer may have an appropriate thickness, but
Preferably, the thickness is between 50 μm and 5 to 20 μm.

The photosensitive layer is formed by preparing a photosensitive layer dispersion containing an α-type titanyl phthalocyanine composition, a charge transport substance, a binder resin, etc., applying the dispersion to the conductive base material, and drying the dispersion. can do.

When preparing the above-mentioned dispersion, etc., an appropriate organic solvent is used depending on the type of binder resin, etc. Examples of the organic solvent include alcohols such as methanol, ethanol, propatool, isopropanol, and butanol. , n-
Aliphatic hydrocarbons such as hexane, octane, and cyclohexane, aromatic hydrocarbons such as benzene, toluene, and xylene, halogenated hydrocarbons such as dichloromethane, dichloroethane, carbon tetrachloride, and chlorobenzene, dimethyl ether, diethyl ether, tetrahydrofuran, and ethylene glycol. Ethers such as dimethyl ether and ethylene glycol diethyl ether, ketones such as acetone, methyl ethyl ketone, and cyclohexanone, ethyl acetate,
Various solvents such as esters such as methyl acetate are exemplified, and one type or a mixture of two or more types can be used. The above-mentioned dispersion liquid may contain a surfactant, a leveling agent such as a silicone solution, etc. in order to improve the dispersibility, coating properties, etc. of the α-type titanyl phthalocyanine composition.

The above-mentioned dispersion liquid can be prepared by conventional mixing and dispersion methods, for example,
It can be prepared using a paint shaker, mixer, ball mill, sand mill, attritor, ultrasonic disperser, etc. When applying the obtained dispersion, conventional coating methods such as dip coating, spraying, etc. can be used. Coating, spin coating, roller coating, blade coating, curtain coating, bar coating, etc. are used.

<Examples> The present invention will be described in more detail below based on Examples.

Synthesis Example 1. Titanyl phthalocyanine was produced by charging 4 moles of 3-diiminoisoindolenine, 1 mole of tetrabutoxytitanium, and a predetermined amount of quinoline into a reaction vessel and reacting at a temperature of 170 to 180°C for 5 hours. Synthesized.

Example 1 To 100 parts by weight of the titanyl phthalocyanine of the above synthesis example, 1500 parts by weight of 4-sulfuric acid with a concentration of 98% was added and dissolved. After standing at a temperature of 25°C for 3 hours, the obtained solution was heated at 0°C. The α-type titanyl phthalocyanine composition is filtered by injecting it into a large amount of water, dispersed in dichloromethane and washed, and the filtration and washing are repeated. The α-type titanyl phthalocyanine composition is dried at a temperature of 80°C. I got it. Further, the obtained α-type titanyl phthalocyanine composition and a predetermined amount of dichloromethane were charged into a ball mill and mixed for 20 hours to produce an α-type titanyl phthalocyanine composition.

The obtained α-type titanyl phthalocyanine composition contained approximately 82.3% by weight of α-type titanyl phthalocyanine.

0.05 parts by weight of the α-type titanyl phthalocyanine composition obtained by the above method, 100 parts by weight of bisphenol 2 type polycarbonate, 100 parts by weight of ethylcarbazolealdehyde diphenylhydrazone, and 1 part by weight of tetrahydrofuran.
A dispersion liquid was adjusted using an ultrasonic disperser using 000 parts by weight and coated on an aluminum sheet to prepare an organic photoreceptor having a photosensitive layer with a thickness of about 20 μm.

Example 2 An organic photoreceptor was prepared in the same manner as in Example 1 using 4 parts by weight of the α-type titanyl phthalocyanine composition of Example 1.

Example 3 Using 5 parts by weight of the α-type titanyl phthalocyanine composition of Example 1, an organic photoreceptor was prepared in the same manner as in Example 1 above.

Comparative Example 1 α-type titanyl phthalocyanine composition of Example 1 0.01
An organic photoreceptor was prepared in the same manner as in Example 1 above using parts by weight.

Comparative Example 2 An organic photoreceptor was prepared in the same manner as in Example 1 using 10 parts by weight of the α-type titanyl phthalocyanine composition of Example 1.

Comparative Example 3 In place of the α-type titanyl phthalocyanine composition of Example 1, 8 parts by weight of N,N-dimethylperylene-3,4°9.10-tetracarboxydiimide was used to prepare the composition of Example 1.
An organic photoreceptor was prepared in the same manner as above.

Then, the charging characteristics and photosensitive characteristics of each of the above photoreceptors were determined using an electrostatic copying tester (manufactured by Shunchik Co., Ltd., Juntefuku Cynthia 30M), and the photoreceptors of each of the above Examples and Comparative Examples were positively and negatively charged. Body surface potential Vsp (
At the same time, the inflow current 1p (μA) was measured. In addition, the photoreceptor is exposed using halogen light,
The time required for the surface potential to decrease to 1/2 is calculated, and the half-reduction exposure amount El/2 (μJ/Cm") is calculated. The surface potential after 0.15 seconds has passed after exposure is determined as the residual potential Vr.
p(V). Further, the electrophotographic process was repeated 300 times for each photoreceptor, and the difference between the initial surface potential and the surface potential after 300 cycles was defined as ΔVsp (V).

Table 1 shows the charging characteristics and photosensitivity characteristics of each photoreceptor obtained in the above Examples and Comparative Examples.

(Hereinafter, blank space) From the electrophotographic photoreceptors of Comparative Examples 1 and 2 in Table 1, it was found that when the content of the α-type ditanyl phthalocyanine composition was 0.05 parts by weight or less based on 100 parts by weight of the binder resin, the photoreceptors If the sensitivity of the photoreceptor is not sufficient, and if the amount exceeds 5 parts by weight, the charging ability of the photoreceptor may deteriorate.
It can be seen that the repeatability is degraded. Further, the electrophotographic photoreceptor of Comparative Example 3 has insufficient sensitivity when negatively charged and has a very large residual potential. In contrast, each photoreceptor according to the present invention has good electrophotographic properties in both positive and negative charging.

<Effects of the Invention> As described above, the electrophotographic photoreceptor according to the present invention has positive and negative effects when it contains an α-type ditanyl phthalocyanine composition of 0.05 to 5 parts by weight based on 100 parts by weight of the binder resin. Both types of chargers not only have excellent chargeability and repeatability, but also have good electrophotographic properties such as high sensitivity and low residual potential.

Patent applicant: Mita Kogyo Co., Ltd.

Claims (1)

[Claims] 1. In a photosensitive layer formed by dispersing an α-type titanyl phthalocyanine composition and a charge transport material in a binder resin,
1. A composite dispersion type electrophotographic photoreceptor having both positive and negative chargeability, characterized in that it contains 0.05 to 5 parts by weight of a titanyl phthalocyanine composition per 100 parts by weight of a binder resin. 2. The electrophotographic photoreceptor according to claim 1, wherein the α-type titanyl phthalocyanine composition contains 60 to 90% by weight of α-type titanyl phthalocyanine and 10 to 40% by weight of metal-free phthalocyanine. 3. The α-type titanyl phthalocyanine composition has black angles of 6.9° and 9.6° in the X-ray diffraction spectrum,
15.6°, 17.6°, 21.9°, 23.6°, 2
The electrophotographic photoreceptor according to claim 1 or 2, which exhibits strong diffraction peaks at 4.7° and 28.0°, and has the largest diffraction peak at 6.9° among the Black angles. .