DE4028519C2 - Electrophotographic recording material - Google Patents

Description

The present invention relates to a electrophotographic recording material, which has excellent properties in Reuse.

Up to now have been used as electrophotographic recording material known those that have a photosensitive layer, which mainly consist of inorganic photoconductors, such as Selenium, zinc oxide and cadmium sulfide.

But these are in terms of their sensitivity, Heat stability, moisture resistance and Durability is not always satisfactory and especially are selenium and cadmium sulfide because of their toxicity disadvantageous.  

On the other hand, have electrophotographic recording materials a photosensitive layer consisting mainly of organic photoconductive compounds is, many advantages. They’re relatively easy to make, cheap, easy to use and generally the Selenium recording materials in terms of heat resistance consider and therefore enjoy this technical field increasing in popularity these days.

As such, it is an organic photoconductive compound Poly-N-vinylcarbazole known. It will be a electrophotographic recording material with a photosensitive layer consisting mainly of one Complex formed from the aforementioned Poly-N-vinylcarbazole and a Lewis acid, such as 2,4,7-trinitro-9-fluorenone, is composed in the JP-AS 50-10496. But this recording material is in terms of sensitivity, film formability and Persistence is not very satisfactory.

On the other hand, organic photoconductors are low Molecular weight represented by hydrazones and Pyrazoline, known. The film formability can by combining these organic photoconductors with suitable binders are considerably improved, is the improvement in sensitivity and durability but not enough.

That is why they are double-layered Recording materials have been proposed in which the generation of Load carriers and the transport of load carriers in separate layers arise. The application of this  Structure leads to remarkable improvements in the Charging characteristics and sensitivity and has one Sensitivity of the recording materials led to close that of the inorganic recording materials, such as. B. those with Se leads, namely by combining a charge generating Layer comprising an azo pigment with a very good Ability to generate charges with a Charge transporting layer that a Contains charge transport material of the hydrazone type, which has a very good ability to transport Has charges. Such are now the Recording materials consisting mainly of organic photoconductive connections of these types are established, used for copying machines and printers.

Electrophotographic recording materials containing these organic Contain materials, but have the problems that with repetition of electrophotographic Procedure, namely loading, exposing and Unloading the copier reduces the initial potential and the residual potential increases after discharging.

DE-OS 29 05 477 is a double layer known electrophotographic recording material in which a special, charge-transferring material is used, and which also includes an epoxy resin as a binder in the Charge generating layer can be used. From this Documentation does not show that the use of special epoxy compounds an improved sensitivity and in particular improved durability can be achieved can.  

The object of the present invention is a electrophotographic recording material is also available represent the improved properties with repeated Has use, and its properties also in repeated use in electrophotographic processes not subject to change.

This task is done through an electrophotographic Recording material according to claim 1 solved.  

As a conductive layer on which a photosensitive layer is applied, those can be used as them in known electrophotographic recording materials be used.  

Examples of the substrate are rolls and sheets Metal, such as aluminum and copper, laminates made from foils these metals and sheets with vapor deposits these metals.

Other examples are plastic films, plastic rollers and papers that make a conductive treatment by coating with conductive substances, such as Metal powder, carbon black, copper iodide, or polymer electrolytes together with suitable binders.

Also plastic foils and rollers, by getting more senior Substances such as metal powder, carbon black and carbon fiber, become conductive are suitable.

The charge generating layer can pass through Dispersing a pigment or dye as that Charge generating material in a solvent, together with the epoxy compound, and optionally in a mixture with another resin as a binder and by coating the Dispersion can be produced on a conductive substrate.

As a binder for the charge generating layer can, for example, conventional and known polymers and Copolymers of vinyl compounds, such as styrene, vinyl acetate, Acrylic esters and methacrylic esters, phenoxy resin, butyral resin, Formal resin, urethane resin, phenolic resin and polyester resin, be mentioned. However, their selection is subordinate Meaning.  

The pigments used are exemplary Azo pigments represented by monoazo pigments, Polyazolone azo pigments, metal complex azo pigments, Stilbene pigments and thiazole azo pigments, perylene pigments, such as perylene anhydride and perylene imide, Anthraquinone or polycyclic quinone pigments, represented by anthraquinone derivatives, Anthanthrone derivatives, dibenzopyrenquinone derivatives, Pyranthrone derivatives, violanthrone derivatives and Isoviolanthrone derivatives, and phthalocyanine pigments, illustrated by metallophthalocyanine, Metallonaphthalocyanine, metal-free phthalocyanine, with a. The dyes used include examples Triphenylmethane dyes illustrated by Methyl violet, quinone dyes, such as quinizarin, Pyrylium salts, thiapyrylium salts and benzopyrylium salts, with a.

The epoxy group-containing compound is in a Amount of 0.1 to 1000 parts by weight, preferably from 1 to 400 parts by weight per 100 parts by weight of the load generating material used.

In the case of using a resin other than Binder is the binder resin in an amount of 1 to 1000 parts by weight, preferably from 10 to 200 parts by weight per 100 parts by weight of the charge generating Material used. The thickness of the Charge generating layer is preferably 0.1 to 2 µm.

As examples of the solvent, ethers such as 1,2-dimethoxyethane, tetrahydrofuran and 1,4-dioxane;  Ketones such as methyl ethyl ketone and cyclohexanone; aromatic Hydrocarbons such as toluene and xylene; aprotic polar solvents, such as N, N-dimethylformamide, Acetonitrile, N-methylpyrrolidone and dimethyl sulfoxide; Alcohols such as methanol, ethanol and isopropanol; Esters, such as ethyl acetate, methyl acetate and methyl cellosolve acetate; and chlorinated hydrocarbons such as dichloroethane and Chloroform; be mentioned.

The charge transport layer can pass through layered application of a solution of a binder and a cargo transport material in a solvent.

The cargo transporting material is in one Amount of 20 to 500 parts by weight, preferably 50 to 200 parts by weight, based on 100 parts by weight of the binder used.

Examples of the binder include polymers and Copolymers of vinyl compounds, such as styrene, Vinyl chloride, acrylic ester, methacrylic ester and vinyl acetate, Phenoxy resin, polysulfone, polycarbonate, polyarylate, Polyester, cellulose ester, cellulose ether, urethane resin, Epoxy resin and silicone resin, with a.

Close examples of the solvent Tetrahydrofuran, methyl ethyl ketone, benzene, toluene, Monochlorobenzene, 1,2-dichloroethane, methylene chloride and With ethyl acetate.

Examples of the cargo transport material  are shown below.

The thickness of the charge transport layer is preferably 5 to 100 microns.

The photosensitive layer of the invention electrophotographic recording material can be known Contain plasticizers that improve the Film formability, flexibility and mechanical Serve strength. Close these plasticizers exemplary phthalic acid esters, phosphoric acid esters, chlorinated paraffins, chlorinated fatty acid esters and aromatic compounds such as methylnaphthalene.

The photosensitive layer can also contain additives, like antioxidants, to improve the electrophotographic properties of the recording material contain and if necessary with an adhesive Layer, an intermediate layer, a transparent Insulating layer or a surface protective layer be provided.  

Example 1

0.2 g of the above azo compound, 0.2 g of epoxy compound, of the following formula I-6

became 20 ml of tetrahydrofuran added and for 2 hours in a paint shaker dispersed. The resulting dispersion was on a Conductive PET film carrier coated with aluminum vapor layered applied with a dry thickness of 0.2 microns and then forming a charge generating layer dried.  

Furthermore, 2.0 g of the Hydrazone compound (II-2) and 2.0 g of polyarylate resin with the recurring units

in 20 g methylene chloride dissolved, and the solution was applied to the loads generating layer with a dry thickness of 20 microns forming a cargo transporting Layer applied in layers, whereby one electrophotographic recording material. This Recording material became a in the dark at room temperature Stored for one day and then determining the amount of cargo at a charge voltage of -4.8 kV using a electrostatic paper tester  subject. It was then the surface of the photosensitive layer with light through a Fluorescent lamp illuminated with 5000 lux for 5 minutes and then again determining the amount of charge under subject to the same loading conditions, which makes it percentage ratio of the charge quantities before and after Lighting received. This was called Pre-exposure characteristic used.

The changes in the initial potential were separated and the residual potential after 10,000 repetitions of the procedure described above by the Capture the Surface potential through a surface electrometer in a copier, from the the Development part had been removed, determined. This one The initial potential mentioned is a surface potential a recording material having a voltage of 750 to 650 V subject without being illuminated, and that Residual potential is a surface residual potential of a Recording material, after which the surface potential by Exposure to discharge had been eliminated.

The results are shown in Table 1.

Comparative Example 1

0.2 g of the same azo compound as in Example 1 was used, and 0.2 g of phenoxy resin with recurring units

and a molecular weight of 35,000 were added to 20 ml of tetrahydrofuran and dispersed in a paint shaker for 2 hours. In the same manner as in Example 1, a Charge generating layer and a charge transporting layer formed, where one electrophotographic recording material.

Pre-exposure characteristics and potential change during the repetition of the process was measured.

The results are shown in Table 1.  

Comparative Example 2

An electrophotographic recording material was as made in Example 1, except that a polyester resin with repeating units

wherein the ratio of (a): (b) is 1: 1 with one Molecular weight from 15,000 to 20,000, as a binder for the charge generating Layer was used. It became its characteristics certainly.

The results are shown in Table 1.  

Table 1

Example 2

A recording material was prepared in the same manner as in Example 1 manufactured, except that the Hydrazone compound (II-5) instead of compound (II-2) was used and the determination of the Pre-exposure characteristics and a 10,000-fold Repeat to determine the change in Initial potential and the residual potential.

The results are shown in Table 2.  

Comparative Example 3

A recording material was produced in the same manner as in Example 1, except that the same binder was used for the charge generating layer as in Comparative Example 1 and that the same hydrazone compound as in Example 2 (II-5) was used. The characteristics of the recording material were set.

The results are shown in Table 2.

Comparative Example 4

A recording material was prepared in the same manner as in Example 1 produced, except that the same binder was used for the charge generating layer as in Comparative Example 2 and the same Hydrazone compound (II-5) as used in Example 2 has been. The characteristics of the recording material were certainly.

The results are shown in Table 2.  

Table 2

Example 3

0.2 g of the same azo compound as in Example 1, 0.15 g of the epoxy resin as in Example 1 and 0.05 g of phenoxy resin as in Comparative Example 1 became 20 ml 1,2-Dimethoxyethane added and through a paint shaker dispersed for 2 hours. In the same way as in Example 1, the resulting dispersion was applied and a recording material was obtained, the Characteristics were determined.

The results are shown in Table 3.  

Example 4

0.2 g of the same azo compound as in Example 1, 0.1 g of the Epoxy resin from Example 1 and 0.1 g phenoxy resin from Comparative Example 1 was added to 20 ml of 1,2-dimethoxyethane and dispersed in a paint shaker for 2 hours. As in Example 1, the resulting one Dispersion applied and it became a recording material manufactured, the characteristics of which were determined.

The results are shown in Table 3.

Example 5

0.2 g of the same azo compound as in Example 1, 0.05 g the epoxy resin as in Example 1 and 0.15 g of phenoxy resin as in Comparative Example 1 were added to 20 ml of 1,2-dimethoxyethane and in dispersed in a paint shaker for 2 hours. As in Example 1, the resulting one Dispersion applied and it became a recording material manufactured, the characteristics of which were determined.

The results are shown in Table 3.  

Table 3

Example 6

0.2 g of the azo compound with the structural formula above, 0.2 g novolak type epoxy resin of general formula I-18

became 20 ml of 1,2-dimethoxyethane added and for 2 hours in a paint shaker  dispersed. The resulting dispersion was on a PET film carrier coated with aluminum vapor with a dry density of 0.2 microns and then to form a Charge generating layer dried.

Furthermore, 2.0 g of the Hydrazone compound (II-2) and 2.0 g polyarylate resin of Example 1 in 20 g of methylene chloride solved and the solution was on the loads generating layer with a dry density of 20 microns forming a cargo transporting Layer applied, making one electrophotographic recording material.

This recording material was in the dark at room temperature kept for 1 day and then determining the Amount of charge at a charge voltage of -4.8 kV below Use of an electrostatic paper machine subject. The surface of the photosensitive layer was illuminated with light by a fluorescent lamp of 5000 lux illuminated for 5 minutes and then again the Determination of the amount of charges among them Subject to charging conditions. It became the percentage Ratio of the quantities of charge carriers before and after Get lighting. This was called Pre-exposure characteristics used.

The changes in the initial potential were separated from this and the residual potential after 10,000 times use by scanning the surface potential through a  Surface electrometer in a copier, from which the development part has been removed was determined.

The results are shown in Table 4.

Example 7

It became an electrophotographic recording material as prepared in Example 6, with the Exception that the epoxy resin with recurring Units of the formula

as a binder for the Charge generating layer was used. It the characteristics of the same were determined.

The results are shown in Table 4.  

Comparative Examples 5, 6 and 7

Electrophotographic recording materials were as prepared in Example 6, except that as a binder for the charge generating Layer the phenoxy resin from Comparative Example 1 (Comparative Example 5) Polyester resin from comparative example 2 (comparative example 6), and Butyral resin with recurring units of the formula

where component x is 14 to 80% by weight, component y is 80% or more, the component z is 3 mol% or less (Comparative Example 7) was used. The characteristics the same were determined.

The results are shown in Table 4.  

Table 4

Example 8

0.2 g of an azo compound with the following Structural formula and 0.2 g of the epoxy resin used in Example 1 were too 20 cm³ 1,2-dimethoxyethane added and together with Glass beads in a paint shaker for 4 hours dispersed to obtain a pigment dispersion.

The resulting dispersion was placed on an aluminum foil With 0.1 mm thick and applied at 80 ° C for 15 minutes forming a charge generating layer dried. The dry thickness of the layer was 0.2 µm.

Furthermore, 2.0 g of the Hydrazone compound (II-2), 1.0 g polyarylate resin as in example 1 a modified one Polycarbonate resin with repeating units

and a molecular weight of approximately 20,000 and 0.04 g alpha-tocopherol as Addition dissolved in 20 g methylene chloride and the solution was applied to the charge generating layer and at 80 ° C for 1 hour to form one Charge transport layer dried,  making an electrophotographic recording material received. The thickness of the cargo transporting Layer was 20 microns.

This recording material was in the dark at room temperature kept for 1 day and then the changes were made in the initial and residual potential after 10,000 repetitions at room temperature by scanning the Surface potential with the help of a Surface electrometer in a copier, from which the development part has been removed was determined. The results are in Table 5 shown.  

Comparative Example 8

A recording material as in Example 8 manufactured, except that the charges  generating layer using a dispersion was prepared by adding 0.2 g of the in Example 8 used azo compound, and 0.2 g of Phenoxy resin of Comparative Example 1 to 20 cm of 1,2-dimethoxyethane had been. The results of the measurements are in Table 5 shown.

Comparative Example 9

A recording material was as in Comparative Example 8 prepared, except that the in Comparative Example 2 used polyester resin was used in place of the phenoxy resin. The Results of the measurements are shown in Table 5.

Comparative Example 10

A recording material was prepared as in Comparative Example 8, except that the in Comparative Example 7 used butyral resin was used in place of the phenoxy resin. The Results of the measurements are shown in Table 5.

Comparative Example 11

A recording material was as in Comparative Example 8 prepared, with the exception that Dodecyl acetate was used in place of the phenoxy resin. The results of the measurements are shown in Table 5.  

Table 5

Change in initial potential and residual potential after 10,000 repetitions

Claims (4)

1. An electrophotographic recording material comprising a conductive support, a charge generation layer containing a charge generating material, and deposited on the substrate, and a charge transporting layer containing a charge-transporting material and is formed on the charge generating layer, characterized characterized in that the charge generating layer comprises at least one of the following compounds with epoxy groups, wherein R denotes a hydrogen atom or an alkyl group and L and M each denote an integer greater than 0; wherein N + Z denotes an integer greater than 0; wherein k denotes 0 or an integer greater than 0, R₃ and R₄ each denote a hydrogen atom or an alkyl group and R₅ denote a hydrogen atom or a methyl group and where o, p and q denote the constitutional relationship and o + p + q denote an integer greater than 0. 2. Electrophotographic recording material according to Claim 1, characterized in that the charge generating layer connects to Epoxy groups in an amount of 0.1 to 1000 parts by weight per 100 parts by weight of the charge generating material contains. 3. Electrophotographic recording material according to Claim 1, characterized in that the charge generating layer is another binder resin in an amount of 1 to 1000 parts by weight per 100 Parts by weight of the charge generating material with the compound containing epoxy groups. 4. Electrophotographic recording material according to Claim 1, characterized in that the thickness of the charge generating layer 0.1 to 2 microns is.